【Astrobites!】 Simulating Star Death!

[00:00:13]Call me somewhere I've never gone. Can't imagine it. But that's what I want. Life's too short to wasted on being withdrawn. Life's too short to wasted at all.

[00:00:32]Oh, here we go.

[00:01:29]I'm bundled up in your clothes again.

[00:01:34]Don't think I've ever felt so warm.

[00:01:38]All my roots sprouted into split ends.

[00:01:43]The smell of linen stains my arms.

[00:01:48]I think I finally understand it now. Oh, life's much too long to not fall in love, but much too short to keep waiting around.

[00:02:03]We run ourselves into the ground. Oh, I'm terrified to tell you. Ooh, but deep down I think you already know if patience is a virtue.

[00:02:21]Ooh.

[00:02:23]Then you're the greatest person I've ever known.

[00:02:28]Ooh.

[00:02:37]Why can't I get it through that head of yours?

[00:02:41]I'm only going to leave you broken.

[00:02:47]You remember me with tears in your eyes.

[00:02:52]A disease that leaves you smoking.

[00:02:56]I think I finally understand now. Oh, I spend my life trying to fit so gave up my comfort for a final chance to grow. And I think I finally found my gold.

[00:03:15]Oh, I think I finally found my home. Oh, I'm terrified to tell you. Ooh.

[00:03:26]But deep down I think you already know.

[00:03:30]And I'm terrified to hurt you. Oh, but I'm different from the girl that I was before.

[00:03:46]Ooh.

[00:04:01]Ooh.

[00:04:06]Ooh.

[00:04:18]things never pan out the way I imagine.

[00:04:23]So I've been imagining for let's wait out my fears connect as it passes.

[00:04:33]Your gentle pull shifted my course.

[00:04:56]Call me somewhere I've never gone. Can't imagine it. But that's what I want. Life's too short to wasted on being withdrawn. Life's too short to wasted at all.

[00:05:16]Oh.

[00:05:26]Hello Orbeez. Okay, I'm going to get on the screen.

[00:05:32]Hello, Spinning C. It's me, Z. Hello, everybody. Um, okay. Sorry, I just need to check that I closed the door. Um, I hope everybody can hear me. All right.

[00:05:43]Um, maybe I've been like playing around with my like microphone settings like moving a little closer or a little further. Does this sound better or does this sound better? Option one. Option two. They might sound the same. I actually It's so hard to like monitor my audio.

[00:06:04]>> Option one.

[00:06:06]Okay. Okay. Maybe maybe option one is the way to go. This is option one, by the way. literally like phone to my face.

[00:06:16]>> You see that hand that's like on the screen? Yeah, that's literally me holding my phone to my face right now.

[00:06:23]>> All right, option one. Okay, maybe option one it is. Maybe I'll just like sit like this the whole time.

[00:06:30]Well, I hope everyone is doing great today. Um, I've been doing attendance these past few days because my last stream was a collab and it's a little bit harder to uh to yap um when I'm on a collab. But maybe I can balance my phone on my water bottle.

[00:06:50]This might be a disaster.

[00:06:53]I just have to find like the center of mass.

[00:06:56]Okay. Okay. Wait, hold up. Wait. I also have a popsocket, so maybe that will help.

[00:07:03]Oh my god. I think I figured it out. How How does this sound? Oh my god. Wait, I actually like balanced my phone on top of my water bottle, which is like it like I propped up the straw part and like put that on the popsocket. This is literally like the greatest engineering feat I've ever done. Wow. Okay, maybe I should take a photo of this later. This is actually I didn't think I'd get that so quickly. Okay. Well, quickly do attendance. Hello, guy from Space, Texas. Hello, give me stuff, please.

[00:07:34]Okay. Hello, P. Hello, Warpy. Oh, whoa, that's a new chat feature. Hello, Data Foxy. Hello, Zilla. Hello, Stella.

[00:07:44]Hello, Astral. Hello, Hug Your Dogs.

[00:07:46]That's a very cute username. Hello, Germanium. Hello, Ary. Hello, Balman.

[00:07:54]I hope everybody is having a spectacular day today. I'm so sorry that this stream got delayed before. Uh hello Jedi. Um so basically yesterday what happened was I was on my way back to go and stream, right? But there was this incredible storm. And I have to I have to preface this by saying that not only is my computer always overheating, but my phone is also it's on its last legs. As in like every time I go on a video call with somebody, I get a notification saying that my phone is overheating.

[00:08:34]And recently, I've been getting notifications that I need to get my battery replaced. And like being abroad and everything, I will probably figure this out once I'm back in the States.

[00:08:43]But just to preface this, my phone is in critical condition, right? And so it's absolutely pouring outside and I'm stuck in a cafe and my phone is saying that it's not raining outside and I'm like, there's no way this is true. And so I refresh my phone and my phone keeps saying there is no rain outside. And I'm like, okay, what is going on? And so I go on my laptop and it's like like critical storm warning like please stay indoors and like it's like some sort of like yellow warning.

[00:09:15]It's like absolutely freaking out and my phone is still saying that it's sunny and not raining outside.

[00:09:24]>> It's not even AI though. It's not even AI. Like it was just straight up the weather app was glitching out and I was just absolutely bamboozled. And so it took me quite a long time to actually make it back. And I actually did have to go outside in the rain. And so by the time I came home, my backpack was completely drenched. My everything I was wearing was like dripping wet. My hair was soaked. Like it was almost as if like I had literally just gone into the shower with everything on. Um it was that bad. So that was the reason why I unfortunately was not able to uh stream yesterday.

[00:10:05]Hello Kami.

[00:10:07]Hello Orbeez.

[00:10:09]Yeah, so that was definitely a a time for sure.

[00:10:15]Oh no, my notebook closed.

[00:10:18]I always have notes open. I always have a notepad open when I'm streaming. But I have started to use my default notebook for multiple purposes now. And now all the pages are everywhere. All right, here we go. Yeah. Yeah. So, that was what happened yesterday. Um, so some quick announcements before we get started with reading about How Stars Die, which I'm super excited to talk about. Um, first off, this stream was made possible because of the charity Dodathon. Um, this was actually a specific topic that was requested by Jedi, who I just saw. Yes. Who's in the chat? So, welcome. Glad to see you're here. Um, and so, >> yeah, it's a super exciting topic and I'm super glad that we're able to talk about it as a result of the Donathon.

[00:11:08]>> So, shout out to Jedi. Other super exciting news is that I am actually meeting another VTuber soon, which I'm so stoked because you guys may remember that it hasn't been that long since I uh since I met up with uh Paris.

[00:11:29]But there is another VTuber union happening soon. And so I'm super excited. Uh more details about this in the future, so stay tuned.

[00:11:44]Oh, I just got a notification on YouTube saying that it's lagging.

[00:11:51]Please let me know if it's broken.

[00:11:56]>> I think it's still working.

[00:12:00]>> Okay, I think it's still working. Uh let me know if it glitches out. Um, but yes, I also realized that there is only six streams remaining until my hiatus or at least six plan streams. It was originally going to be more, but I found out actually the same day as this torrential rain that I am invited to give a talk. And so, as a result of that, I actually had to cancel two collabs that I was like incredibly excited for. Um, one of them was going to be like a large group collab. So, I'm really sad about missing that, but I'm sure you guys will hear more details about that in the future. And please join. And I will also include the details in the Discord as well. Speaking of, um, I should probably It's fine for me. Okay. And it might just be on my end then.

[00:12:49]Um, yes.

[00:12:52]Um, there is a Discord, by the way. I keep forgetting to advertise that. Anyh who, uh, let me get my articles up. So, today might be a bit of a shorter stream, just the length of what it'll take to read these articles and talk about them.

[00:13:10]>> I am actually dealing with a really bad like eczema rash. I don't know if anybody else has dealt with this before and like if so, like what you did to cure it. Um, basically >> I I don't know if there's any like doctors or pe skin experts in the chat, but basically what happened was um as a result of the heat wave, I got a really bad like sweat rash on my arm. Like I think like my pores are getting clogged or something. But anyh who, I went to the pharmacy and they gave me this ointment that would help dry out my skin a little bit. and then my skin got too dry and now that same rash has like become this really dry patch of skin.

[00:13:56]Um, and it's basically the symptoms of eczema. And so I went back to the pharmacy and I was like, "Hey, like you know the sweat the the heat rash is gone now, which is good, but now I have this new rash." And they were like, "Yeah, no, this is definitely eczema." like we've been getting a lot of people with like skin conditions recently because of the heat combined with the fact that like I need to nutrition myself a little bit better and so I have this like horrendous like rash on my arms that I've been trying to combat. So if you have any suggestions on how to treat eczema please do let me know. Um whoa wrist is doing a thing.

[00:14:31]I'm new. Have you by chance researched this topic before? So no, I have not researched the specifically the death of stars, but I would say that I have done a lot of uh stuff in simulations in astrophysics and so I think some of the articles that we'll talk about today will delve into that. I kind of skimmed over these three astrobes, but I will this is like the first time I'll be reading together in depth. So this will be a great opportunity to learn together as well. So, if you have any questions, I'll do my best to answer and if I don't know, we can Google it together and learn together. So, yippee. Um, >> actually, let me just quickly uh pin the uh super.

[00:15:16]Maybe you can still prevent eczema if it's not yet full-blown by applying skin moisturizer daily. Yeah, I've been using. So, originally I was just using body lotion and then they were like when I went to the pharmacy and I I actually brought the lotion I was using. It was just like the plain old like Neutrogena lotion and they were like, "Oh, like because of how sensitive your skin has become as a result of this heat rash, we actually don't think that this lotion is even good for you. Like you need to do something that's like much softer or like much better for sensitive skin."

[00:15:52]And so they actually like prescribed me something. Yeah. No, I don't know what's going on with my skin. It's a little bit concerning. Um I think like because of the heat too, but yeah. Well, one thing to look forward to and then we're going to actually delve into this article is that tomorrow I'm actually taking my first trip for myself. So I have been in Germany for I think like about a month now. And this whole time I have only been traveling for work, which has been fun. Um, but I haven't had the chance to explore anything in the area around me.

[00:16:25]Actually, the other day I was talking with like some of my like research friends and they were like, "Yeah, like have you visited like this major like landmark in the area that I'm at?"

[00:16:37]And I was like, "No." And they were like, "What are you doing?"

[00:16:41]>> And I was like, "I'm sorry." Cuz like the first week I was really jetlagged.

[00:16:46]The second week I had to travel for um my my talk and then the third week I don't know I think I was traveling again for something else and I think it's like almost the fourth week now. I I don't remember I lost track of time but basically yeah so tomorrow will be my first day actually going out and traveling for fun which I think will be a much needed and very exciting break.

[00:17:09]And one of the things that the pharmacist actually said is that these kinds of rashes, although they are induced by heat, they can be worsened by stress. And so I think maybe a nice fun vacation will be great, too. Maybe it's the German weather. I honestly think it is. But I heard that the heat wave is going to get better. I want a drink of water, but my uh here I'm going to move my phone for a second.

[00:17:35]All right. All right. Now, I got to balance my phone back on my water bottle. Oh my god. Oh, okay. Yes.

[00:17:44]Let's hope you won't have trouble with the Deutsch Pan. Actually, I have to admit that the train system in Germany, although the trains tend to be very late, it is very easy to actually plan trips. Um the app is really helpful. Um, and if you have this thing called the the Deutseland ticket, you can actually um take all the regional trains for free for a month. It's like a monthly monthly subscription. So, I'd highly recommend that. Honestly, maybe I should do a video about like conducting research in Germany and stuff like that. Some or with some tips that I wish I had prior to coming here.

[00:18:19]All right. Well, without much further ado, let's read our first article. Um, so this is titled Remnant Tales: Uncovering the Link Between Type 1A Supernova Ejecta and Planetary Nebula.

[00:18:29]Um, and again, for those of you who are new here, Astrobittes kind of converts these research papers into more accessible summaries. Um, and so if you go to the link in the chat, you can click the original research paper here.

[00:18:44]And yeah, whoa, this article starts out really funkily. Volatile universe.

[00:18:51]Impermanence, the indelible signature of the universe.

[00:18:56]Wow, that's so dramatic. Transient events such as energetic stellar explosions and chaotic mergers expose the variable essence of the cosmos.

[00:19:04]Observe from afar, these stunning events splatter poly chromatic ink haphazardly across the cosmic canvas. Wow, this is like some beautiful artwork here.

[00:19:12]Despite their violent nature, though, these events enrich the voids of space with the precious ingredients necessary to birth new stars.

[00:19:20]Later, we need to figure out who wrote this because this is beautiful. While each newborn stars evolutionary path is unique, the initial condition that triggers their eventual demise is uniform. Hydrogen fusion within their cores becomes exhausted. For stars lighter than eight solar masses, these cores become helium dominated and begin to contract. As temperatures rise and contraction ensues, carbon and oxygen overtake the region. Hydrogen and helium shells then form around the star center and the temperature gradient between the two induces the propagation of thermal pulses. Consequently, the stars outer layers are expelled in the turbulent process. I just love explaining to people that um uh that literally the supernova remnants that you see in the night sky or even the planetary nebulas, they are literally the outer shells of dead stars.

[00:20:16]Hey, Zenai. Hello, Pan. Good seeing you.

[00:20:19]It is always funny that we call the Deutsch Germans and the Netherlanders Dutch. Actually, what's really funny was when I first tried to look for the German flag emoji, I like couldn't find it for a solid like 10 minutes and then I Googled it and it's because it was like listed like the abbreviation was like DL or something for for Deutsland and so I was like looking for the German I was just typing Germany into my keyboard.

[00:20:46]Yeah. Um okay, where were we?

[00:20:50]Yes. In a dazzling turn of events, the the the core continues to contract until electro degen electron degeneracy pressure commences and produces a dense white dwarf which ionizes the expelled stellar matter and the local circumstellar medium. The resulting entity is deemed a planetary nebula. In many cases, this is only an intermediary act within a much grander event. If accompanied by a companion, often a red giant asmtotic giant branch star, a white dwarf can begin to siphon matter from its neighbor. If it accumulates sufficient mass and exceeds the Chandra seeker limit, 1.44 solar masses. I love this limit. Electron degeneracy pressure falters in its nailbiting duel with gravity and the stars belly ruptures in a dramatic type 1A supernova event. So, it's a critical mass once once you hit the critical mass during the stellar fireworks. Brilliant shock waves are ejected into the depths of space and can approach 6% the speed of light. That doesn't sound like a lot, but that's really fast. The ejected material and the interstellar material swept by it form a supernova remnant.

[00:21:52]So while supernova So while type 1a supernova, so this snee here means supernova because the plural of supernovas is supernova, which I think is pretty cool. And the 1A is the specific type of event that we just discussed. The properties of the companion star, the accretion dynamics of the progenitor system, and the features of the ultimate explosion remain inconclusive. To to address this, the authors of today's paper analyze the morphology or the shapes of type 1A supernova remnants and their impact on the circumstellar medium to better understand these events. That is so cool. And the inner layers get crushed into a little ball. Yes. I mean, what's like white dwarfves? What what is left of these stars are literally just the cores of these dead stars. Isn't it DE? Yeah, it might actually be DE. Sorry. Yeah, this author makes the events. I love the way that I I don't know if you're here at the very start, but it was like impermanence. The indelible signature of the universe. I love this author's writing style. It's so beautiful.

[00:22:58]Well, it's uh yes. Okay. They focus their attention on the renowned Kepler supernova remnant and its impact on the circumstellar medium. Existing models of this remnant suggest that an AGB, an asmtoic giant branch, so it's a very specific type of like red star, survived the supernova 1A event and is now casting winds that are strongly interacting with the circumstellar medium in the remnants northern region and is producing sidelopes. However, no observational evidence has confirmed the presence of an asenta giant branch in the center of the Kepler's supernova remnant. I keep seeing SNR and I keep thinking signal to noise ratio, but SNR is supernova remnant.

[00:23:41]Crazy oneliner. Yes. Sounds like something from humorous sci-fi. I love it. I feel like with these Astrobittes, you get so much flexibility and creativity that you can really put on the page. And I love when they when the authors just have fun with it because frankly astrophysics is so much fun. The emotional gravity that they deserve.

[00:23:59]Yes. Also during a supernova, what immediately perceived the explosion is the core of the star imploding at the quarter of speed of light and the outer layers just bounce off the ball of iron.

[00:24:09]Yes. Yes. That is just so cool to me.

[00:24:11]Like these events are incredibly powerful. Immediately precedes Yes.

[00:24:15]Precedes the explosion. Mhm.

[00:24:18]Hydrodnamics to the rescue. So they are simulating these the depth of stars which I think is so cool. Using the hydrodnamic code AMRV VAC the authors explore the idea that a fraction of type 1A supernova occur in and primarily interact with planetary nebula rather than the asintoic giant branch star of the progener system. In their models they consider the time delay between the formation of the planetary nebula the white dwarf ionizing the circumstellar medium and the eventual supernova 1A detonation.

[00:24:50]Okay, so let's take a look at what's going on here because that was a little bit confusing. Um, >> figure one showcases three varying simulations that the team executed. So, the type 1A supernova occurring Oh, I realized that you guys can't see my uh my mouse. Let me fix that.

[00:25:08]Okay, so >> type 1A supernova occurring simultaneously with the formation of a companion white dwarf >> with a time delay of 2 million years and a time delay of 8 million years. Wow, these look really different from each other.

[00:25:24]>> So they modeled a circumstellar medium, so the surrounding medium based off of how much delay there is between the supernova and the formation of the white dwarf. So, the longer the delay is, it looks like the more spread out. And there's some interesting structure that's going on here. But let let's keep on reading. Model A showcases a supernova event that features a bipolar planetary nebula S1 2 in the progenitor system. There is no time delay between the supernova and the formation of the companion white dwarf. The results reveal that an inner cavity forms, okay, here. And is encompassed by a dense halo of the nebula. Model B presents results after a two million-year time delay.

[00:26:06]Here the high radial momentum of the model's fast winds causes the circumstellar medium to expand. Okay.

[00:26:12]And form a low density cavity of 7 kilopar 6 around the progenitor system.

[00:26:19]Low density cavity. Okay. So now it's a little bit bigger. Okay. So now the cavity is this big. Finally, model C displays the circumstellar meter transitioning from a pressurdriven to momentum driven mode that forces the circumstellar meter to collapse under the pressure leading to a more homogeneous system. Yeah, cuz I was going to say, so there is a little bit of a hole here. There's a bigger hole here, but there's no hole here. And that's a result of this delay.

[00:26:47]A solid fraction of the elements are produced in a short span of time during supernovas. I mean all of the elements other than hydrogen and helium were formed in the core of stars. Like we would not exist without the death of stars which is really cool.

[00:27:03]>> Yeah. No, this is super cool. I love these visualizations.

[00:27:08]Okay. The results from the simulations are effective at producing some of the morphological features observed with Kepler's supernova remnants. So now they're comparing it to this observation. However, to optimize their results, the researchers subsequently input the observed system systemic motion as well as the estimated injected energy, mass, and velocity of the remnant into the model. The revised model show that shocks are able to penetrate the lower density ambient regions in the simulations and reproduce the ears.

[00:27:38]Oh, I did not know. So, I Kepler supernova here. I did not know that they had these ears on the sides. Wait, that's kind of cute. That's kind of cute. It's like a face with ears.

[00:27:50]I also just love how fluffy this nebula is. It's l this supernova remnant is. It literally just looks like a cotton ball.

[00:27:57]A cotton ball with ears.

[00:28:00]Hello, Erica. Lightly. A lot of heavy elements are formicas too. Yes. Yes. And also uh yes, neutron stars also form many elements as well. New mascot.

[00:28:14]Maybe, >> maybe this could be the new Orbeez. A fluffy Orbee. A fluffy Orbee.

[00:28:22]>> I don't know. It looks super cute. I love it.

[00:28:28]>> Wait, this is so cute.

[00:28:31]>> A new ma mascot indeed.

[00:28:37]Uh, let's see.

[00:28:39]Okay. So, a model of the density of the circumstellar medium that surrounds Kepler supernova remnant at the time of the explosion. A model of the density contours of the remnant after 420 years of evolution. Oh, so they took this model basically after formation and then they evolved it after 420 million years.

[00:28:57]Oh no, 420 years. Kepler supernova remnant is that young.

[00:29:04]Wait, that's crazy. Wait, what?

[00:29:13]Oh my god, it is 420 years. I thought it was like at least a thousand years.

[00:29:20]>> I wonder if they have like a a gif of it.

[00:29:25]>> What's really cool about uh supernova remnants is that sometimes you can see them expand in space.

[00:29:41]Yeah. Yeah. Yeah. So, here's a really good example of that.

[00:29:48]I love this object.

[00:29:52]This is a s a supernova remnant and we've been able to track it throughout time and build this gorgeous animation. It's so fluffy.

[00:30:04]>> But it's crazy that you can't like obviously because the the animation starts after the explosion, >> but the stars themselves remain to look mostly the same. It's just this gas that emerges, it really demonstrates how powerful these events truly are.

[00:30:25]>> Hello, Cool Johnny.

[00:30:27]>> Would be cute. The Orbeez do need their fluff. That is true.

[00:30:31]There are supernova that have been recorded in ancient history. Yes, the Crab Nebula was first observed in 1054 famously.

[00:30:39]Um actually uh Kim and I talked about that during our last stream where we ranked uh space objects and we talked about the Crab Nebula.

[00:30:47]Oh, that is true. Kepler supernova since you described and Kepler did live 400 years ago. I don't know. For some reason, I thought it was longer. Well, I I know that Kepler did live around 400 years ago. I just thought the supernova was around for longer.

[00:31:02]its growth is actually due to a light echo. Well, I guess it's able to So, these uh these researchers were able to model that using another example here.

[00:31:12]And by evolving it, they were able to recreate these ears that were formed in Kepler supernova.

[00:31:20]That's super cool that they were able to capture that kind of gas detail.

[00:31:26]The results from today's paper are intriguing. The authors have provided strong preliminary evidence that a planetary nebula occupies Kepler supernova progenitor system rather than an asotopic giant branch star. Their ability to reproduce the morphology of the remnant and its surrounding circumstellar medium suggest that an alternative mechanism may be necessary to explain the dynamics of type 1A supernova.

[00:31:49]Ultimately, the authors offer valuable insight into the role of planetary nebula in the evolution of type 1A supernova.

[00:31:57]Yeah, because they were able to model it. Um, the formation of both at the same time. As we inch closer towards unraveling the properties of stellar evolution today, the universe tirelessly churns. We fervently seek to elucidate its dynamical spirit. All the while in the midst of our pursuit to comprehend its mysteries, cataclysmic an inhilation annihilation.

[00:32:24]And okay, wait. I just like totally forgot how to say that word for a second. A majestic creation remain its signature. As we peer deeper, the hues, Eggy, the hues will continue to grow more radiant as they sprawl further along the cosmic canvas. Wow, this is beautiful. Who wrote this?

[00:32:43]No wonder he already has published two books.

[00:32:48]James Negus is currently pursuing his PhD in astrophysics at UC Boulder. Cool.

[00:32:55]Oh, not UC B.

[00:32:58]See you Boulder. I just read the letters one by one. Yes, at CU Boulder, he analyzes active galactic nuclear. Okay, so he studies super massive black holes.

[00:33:08]He doesn't even study these supernova.

[00:33:11]It's really incredible like how much research and detail is put into these articles. He enjoys stargazing with his 8 in uh Dubsonian telescope and hosting outreach events. He has authored two books. Black holes explained, Mysteries of Space and Supernovas Explained, Mysteries of Space. I was going to say I was like the the amount of like uh like uh pro like the amount of pros in this astrobite is more than what is typical.

[00:33:39]It made me contemplate that this person has either written books before or has written space related pros. And I guess that is the case.

[00:33:56]Are you going to super simulate supernovas or look at simulations of supernovas? Well, it on today's stream, are you asking that? Uh because uh on today's stream, we'll just be reading about simulations of supernovas.

[00:34:08]Hello, upside down engineer. Watching this as I'm falling asleep. Oh my god, 3:00 a.m. Oh yes, the VOD will be up with timestamps. Definitely please get some good sleep, get some good rest.

[00:34:16]Very important. Kepler lived in Germany.

[00:34:19]If you have time and money, you could visit some places related to him. Yes, I did see that. I did see that. I did see that. I'll see since I'm only here for not that much time left. So, I'll try to see if I can visit some places. I actually haven't even searched. There might be some place nearby.

[00:34:36]>> I have a bigger telescope than him. Oh no. I love this writing though. This one was great.

[00:34:43]>> Yeah. Shout out to Shout out to James.

[00:34:46]This is great.

[00:34:52]All right, I'm going to get a sip of water while balancing my phone again.

[00:35:03]Oh, >> I don't know if uh some of you guys were at the start stream, but basically my current mic setup is balancing my phone on my water bottle using a popsocket.

[00:35:24]Balancing it on the straw part of my water bottle. Have a great rest of stream. Thank you so much, Astral, for joining. I will see you later.

[00:35:33]All right, next article. Another simulation of star death. I love this. This is such a cool topic. Um, an elegy to supernova remnant 3C397 simulating stellar death.

[00:35:50]Okay. Uh, before I forget, let me pin this.

[00:35:55]You're also an engineer with that mic setup. No, for real. It is uh >> it is definitely my greatest engineering feat right now.

[00:36:09]>> I'm like so scared that it's going to fall off. Like every time I take a sip of water, it's a little bit precarious.

[00:36:26]All right, I just pinned it.

[00:36:32]>> Okay.

[00:36:38]All right. What is your favorite exoplanet system that Hello, Shadow Worm. Um, that's a great question. I don't know if I have a favorite exoplanet system. I think the Trappist system was really cool, but I think the one downside of it was that it got really blown out of proportion. Um, and unfortunately now they found that a lot of those planets are inhospitable to life. But I think Trappist was one of my favorite systems because it demonstrated that a many exosolar systems like exoplanet system could be possible. Um and that the solar system was not unique.

[00:37:19]>> Did the storm clear?

[00:37:21]>> Yeah, I mean a little, but uh I have been indoors and I'm safe now, which I think is all that matters.

[00:37:30]Oh my god, yesterday was such an ordeal for real.

[00:37:34]um yeah, I talked about it a bit at the start of the stream, but basically my phone, which has been um very laggy, uh was saying that it was actively not raining when it was pouring and I actually had to end up running/walking in the rain and came home like basically completely drenched. Um so I had to have some warm tea to like prevent myself from getting a cold. Do you find any interesting foods and drinks in Germany?

[00:38:04]Actually, uh, just the other week I did go out to dinner with some of my research friends. Um, and I got a knuckle of pork.

[00:38:15]It was really good. Like the skin was just like it was peak. Um, and then I got like a beer sampler and I tried all four of the beers that they gave and there was one beer in particular that I like the most. And so I was telling my friends, I was like, "Yeah, like people were asking like, oh, like cuz we were passing the sampler around. People were like, "Oh, which one do you like the most?" I was like basically sipping out of only one. And I was like, "Gosh, like this one is great. I love the flavor.

[00:38:42]It's so sweet." And then the and then the waitress comes around and she's like, "Yeah, no, the one that you have is really popular." And she she was like, "Actually, it is especially popular because of its high alcohol level." And I was like, "What?" because like it tasted so sweet to me that I thought it would be one of the ones with less alcohol. And she was like, yeah, it's like 20%. And I was like, what?

[00:39:06]I was like, there's no way. And she was like, yeah, no, like it's pretty surprising to people when they visit, but it's like because of the like the fermentation process. And like I was like, there like this this is literally an impostor because it's so sweet. Like I could have never have guessed.

[00:39:24]And what's crazy to me is that like you know you can get the beer as like a pint, right? And so like you know I I didn't have the pint, but I had a pretty solid portion thinking that it was you know roughly the alcohol level of beer.

[00:39:40]And like I was like basically like halfway through when she informed me of this and I was like, "Oh shoot, I'm so cooked."

[00:39:50]It was such a time.

[00:39:53]What surprises me about explosives so far is that there aren't many like hours. Yeah, but I think a part of it might just be like detection detectability as well.

[00:40:04]I think um it would be really cool to find an exoplanet that can possibly host life. And I think nowadays that's become easier to find and there have been some pretty solid candidates with the rise of telescopes that can actually peer into the atmospheres and extract their spectral information.

[00:40:21]I love rain and storms so much and my mom is not happy about these. Yeah, I mean I do love rain. I just don't like rain when I have no umbrella and my phone is dying and I am drenched. Other than that, I do love rain and I love reading in the rain. I love drinking coffee on a nice day of rain. Um but yeah. Wow. 20%. Yeah. No, I was so shocked. I was so shocked. By the way, when is the Q&A? Okay. Yes. Um, lots of questions. Um, all right. I'll take a brief intermission to kind of explain my planned schedule right now.

[00:40:59]So, it is likely that the Q&A will be my last stream before my hiatus because there has been a lot of things to celebrate and I wanted to sort of group all the celebrations together all at once. Um, so for that I will be celebrating both the 10,000 subscriber milestone and I'll probably do a bigger celebration for that when I'm back sometime. Um, and uh and and my technically my second birthday and my second anniversary both occurred this month and I have not done any celebrations for them. So, just as an FYI, the Ask See Anything stream might be my last stream before my hiatus. So, sometime on August 12th. The week before that, I'm actually planning a stream with viewers. Um, this has been requested before and I think I can get something together. Um, maybe playing Gartic Phone. That might be a bit fun.

[00:41:56]Um, I also thought about Among Us, but I don't know like what the limit of players are for that. So, yeah. Um, yeah. And then I do have one more milestone from the Donathon that I will complete, which is playing Cell to Singularity. And then I have two collabs coming up, which I'm so excited about.

[00:42:17]Um, but yes, that's basically the schedule coming up.

[00:42:21]So, a few collabs. I I felt so bad. Uh, I know Pan is in the chat as well. So Pan and I were actually planning a collab, but that weekend I actually have to miss out on two collabs that I was planning for because I'm traveling again to give a talk.

[00:42:40]>> So yes, so the Q&A will some be sometime mid August.

[00:42:45]>> I was brought up to the rain cuz the photography opportunities are insane. I also think dancing in the rain is also a little bit fun sometimes. Um well, not dancing or at least just vibing to music. The issue is that I don't want to damage my headphones. So, sometimes I just like, you know, enjoy the rain on my face when it's light, you know, not when it's like a downpour. How long are you going to be gone for? Um, unfortunately, I cannot say. Um, if you go to my announcement video, I said sometime something between several months to a year. Um, I think it really depends on a personal project that I have been working on that I'm super excited to be working on. And so, um, it really depends. It really depends. Sell the Singularity. I'm actually so excited to play it and I think it's the kind of game that I might play even after I finish uh streaming. The limit is 15.

[00:43:35]Really? Among Us is 100. Wait, I'm getting some conflicting information here.

[00:43:42]>> I might need to search this up later.

[00:43:43]The maximum players of Among Us.

[00:43:49]>> I bought waterproof earbuds only for the rain cause the monsoon here goes crazy.

[00:43:53]Oh, really? Well, I hope you also stay relatively undrenched as well.

[00:44:02]>> All right, I think it's time for us to go to our next article. I'm so excited to read this. Hydrodnamical simulations favor a pure deflration origin of the near chandraar mass supernova remnant 3C397. Actually, a I want to look up how to say defl deflagration. What does that even mean?

[00:44:23]Deflagration >> is a subsonic combustion in which a premixed flame propagates through an explosive or a mixture of fuel and oxidizer.

[00:44:36]Interesting.

[00:44:39]De deflration.

[00:44:42]No, deflegration.

[00:44:46]Wait, I'm going to wait.

[00:44:49]Deflegration in Okay, that's really weird. In the UK it's deflration and in the US it's deflration deflration deflration tomato tomato.

[00:45:03]All right, let's read. Just like humans, there are many different ways in which a star can die. In broad terms, astronomers talk about supernova, which are the luminous and cataclysmic deaths of stars. However, things aren't so straightforward. Stellar deaths can be classified based on a variety of factors, including the properties of the star before it died, the explosion itself, and even the environment in which the supernova occurred. Oh, oops.

[00:45:27]But for today's bite, we're particularly interested in type 1A supernova. These highly luminous stellar dust occur when compact stars known as white dwars accrete matter from a companion star until their mass equals the Chandraseker mass, the theorized maximum mass of a white dwarf. In today's bite, we're looking at 3C397. Oh, this. Oh, it's so beautiful. A galactic type 1A supernova remnant that was analyzed by a group of eager researchers hoping to better understand the ins and outs of stellar death. So cool.

[00:45:57]3C397 is located in the Milky Way galaxy and has been observed at a variety of wavelengths, but most importantly in X-rays. X-rays are a great way to understand supernova remnants because they can reveal which elements are present in the ejecta, the stellar material that is expelled by the star as it dies. This in turn hints at the composition and explosion type of the star before it died. Importantly, 3C397 was observed with the X-ray space telescope Suzaku which showed the high mass ratios of manganesees is MN manganese iron, nickel iron, and chromium iron elements that are expected to be present in large amounts in type 1A supernova remnants. By comparing these results to models, researchers realized the progenitor of 3C397 must have been a near Chinderseker mass white dwarf. Wow, a lot of abbreviations here. So, basically they're showing they traced the elements in this remnant and saw that it was actually a white dwarf that caused it. So, it was caused by type 1A supernova. In addition, XMM Newton observations revealed that the distribution of iron group elements in the ejecta was unevenly distributed and clumpy. While 3C397 is classified as the remnant of a type 1A supernova, the authors of today's paper wanted to understand even more about its tragic demise. Namely, the precise explosion mechanism that take place, >> deflrations, detonations and everything in between or defrations I guess. For near Chanderseker mass type 1A supernova, there are two main explosion mechanisms known as deflegation to detonation transitions or pure deflogrations. I did not know that actually. I'm I'm learning right now.

[00:47:45]DDT type 1A supernova occur when a slow burning bubble rises buoyantly through the convective region of a near change of secret mass white dwarf triggering a nuclear detonation which completely destroys the star in the process.

[00:48:01]Pure deflogrations also consist of a bubble that combusts and travels to the body of the white dwarf. However, these events never trigger a detonation permitting the bubble to reach the surface.

[00:48:14]Okay, so in the case of a deflogation to detonation transition, there is a bubble that rises.

[00:48:22]But for a pure deflogration, wait, they both cause bubbles. But oh, but the bubble this time does not trigger a detonation. So, the bubble actually just like reaches the surface.

[00:48:35]Okay, interesting.

[00:48:37]Since only a small part of the white dwarf is burned, the resulting supernova is dimmer and occurs over a shorter time still scale compared to a DDT event.

[00:48:46]Okay. Therefore, given that 3C 397 is the remnant of a near Changerseker mass type 1 supernova, it was most likely formed either via a DDT or a pure deflogation. To understand which mechanism occurred, the authors of today's paper conducted a suite of two-dimensional hydrodnamic simulations, raring a range of properties, including the density and metalicity of the white dwarf in the explosion type. I would like to preface this by saying that in many cases when you're trying to test with observations, you test a range of different properties and see which one is able to reproduce observations. So I guess uh these two models are comparing the top row shows the DDT model. So in this case, the bubble rises and it triggers a detonation event. So I guess that's what's going on here.

[00:49:36]So this is iron chromium and chromium to iron ratio.

[00:49:39]And in this case, we have a pure deflegation model. In this case, the bubble actually reaches a surface. I guess it does kind of look like that.

[00:49:49]This is so cool. By the way, this is all simulated inside of a computer.

[00:49:56]Oh, I've been totally missing out on chat. Let's see. The gentler version of detonation.

[00:50:01]>> Yeah, like rocket engines and firearms.

[00:50:03]>> Thank you, Stella, for stopping by. Have a good rest of stream. Thank you, manganese. Yes.

[00:50:11]>> How do do all supernova result in nebulize? Yes. So, the official term for the the the remnant that a supernova leaves behind is a supernova remnant.

[00:50:20]That's typically in the case of a more massive star um such as like the Crab Nebula um and that is a nebula. There are also planetary nebulas which are formed when a sunlike star dies and the these have different shapes. So one example is the is the ring nebula, the Helix Nebula.

[00:50:39]Those are planetary nebulas formed from the deaths of sunlike stars. The word nebula just kind of just means like a collection of like colorful gas or just a collection of gas in general. And because the death of a star means that all the material is being blown out into space, um it does mean that all supernova do result in nebula just because they eject their outer layers into space and that is what forms the nebula itself.

[00:51:03]Hope that answers your question.

[00:51:06]All right, so let's see how they use the simulations. Okay, so the results of the simulations are shown here which gives the final supernova ejection distributions for the DDT model with the high density and large bubble offset from the center of the white dwarf and for the pure deflogation model with a high density and a small bubble offset below. From left to right, the three columns show the distributions of iron, chromium, and the ratio of chromium to iron, two important elements for near Chanderseker mass explosions. What the authors immediately noticed was the difference between how structured the ejecta is in each case. More specifically, the DDT model is highly stratified and ordered.

[00:51:40]Yeah, I mean it looks like everything is pretty evenly distributed.

[00:51:45]Um, while the pure deflegation model is highly asymmetric and clumpy. Yeah, I mean you're seeing these like little clumps in here.

[00:51:53]It's kind of giving brain.

[00:51:55]The authors argue that the disorder seen in their pure deflogation simulations is an imprint of the fuel the fluid instabilities that were present in the star prior to explosion which were maintained due to the lack of detonation. Wait, that's crazy. So the fluid instabilities that existed in the star are then reflected in the supernova remnant. On the other hand, the structure of the DT model is ordered since the detonation wiped away any trace of these hydrodnamical instabilities. To end, the authors compared their simulation output to the real life observations of 3C397 from Suzaku and XMM Newton. What they found was that the ejected clumpiness as well as the chromium iron ratios were well reproduced by the pure deflegration model. So basically this one was correctly clumpy one with a high central density. So while the star that created 3C397 might be lost, it is not forgotten. At least while there are keen astronomers simulating its death and trying to understand its tragic demise.

[00:52:52]That is I love that ending. Yeah.

[00:52:56]Thank you, Sonja Panchchov, secondy year PhD student at the University of Melbourne who actually studies supernova remnants in the Magelanic clouds.

[00:53:05]>> This is so cool.

[00:53:12]>> What's a neutron star? How is it different from a black hole? That's a great question. So, based off of the mass of the original star, different types of remnants can be formed. Um so if a star is between I think it's like three and eight solar masses it creates a neutron star and if a star is more than eight solar masses creates a black hole. So what so what I mean by that is that at some point a star dies and it's caused by that because it sort of runs out of fuel and is unable to sort of collapse accrete fusion to prevent itself from collapsing on itself. In the process it leaves behind a remnant at its center which is the neutron star um or a black hole. A neutron star is different from a black hole in that I think a black hole is just kind of a more extreme version of a neutron star. There might be some people who hate me for that, but um the way that it works is that the black holes as you guys may know um all of the even light cannot escape because there is a singularity at the center. That singularity is a black hole. Um, a neutron star is sort of a less massive version of that in which it is an incredibly dense high-gravity object, but not to the point that it has collapsed upon itself even further to form a singularity with the black hole.

[00:54:38]>> So, yeah, I hope that answers your question. So, it really depends on the mass of the progenitor star. Um, if it's in between something that's more like a sunlike star and a much larger star, then it forms a black uh then it forms a neutron star.

[00:54:56]Did it hurt when Yum exploded because you're super No.

[00:55:00]>> How much PC power would these simulations need? I don't know if I could speak about these simulations, but I mean, >> I'm not sure if PC power is the right term here. Typically, what goes on in simulations is that you can actually use um CPU hours. And sometimes these simulations can go on for me for for a very long time. Some of our most largest cosmological simulations, so simulated the entire universe in a box basically can be run for years at a time.

[00:55:33]>> That would require millions of CPU hours.

[00:55:37]>> I'm not sure about these simulations in particular. Actually, maybe I can pull up the If you go to the Astrobite, you can actually pull up the original article. Um, I tend to not be able to show I'm not usually showing these because they have a lot of copyright restrictions, but I will go and quickly check and see if they have some details.

[00:55:54]So, they are using the flashboard hydrodnamical code.

[00:56:03]>> Um, >> yeah, I don't think it says anything about the config. They show the configurations of the different models, >> but >> they don't actually say the the time.

[00:56:29]>> Let me go to the acknowledgements real quick. Or it's down here.

[00:56:36]>> I'm just scrolling through the acknowledgements real quick.

[00:56:41]I mean, yeah, they definitely did use a supercomput um flash.

[00:56:50]>> Yeah, it doesn't say like how much CPU power or how much uh compute they used, >> but the specific package that they used was this flash package.

[00:57:04]This flash code. Yeah, I I'm unfortunately not able to find any additional details, but that's a great question. But I would have to say that for some very intense cosmological simulations, it could literally take millions of CPU hours.

[00:57:20]>> I love computer simulations. Yeah, I think they're so cool. I think computer simulations are one of the coolest ways to think about space nowadays. It's just so insane to me that you can like literally build a universe in a computer.

[00:57:41]Neutron stars are at the verge of getting it nuts density to increase its escape velocity to C. Yes, that is correct. Yeah, that I guess that's a better way of phrasing what I just said.

[00:57:49]Hello. Hello. A aa1a hello a neuters are pretty much as close as something can get to a black hole without becoming one. Yes.

[00:58:00]Do neutron and black holes both implode?

[00:58:03]I'm not really sure what exactly you mean by that. They are both formed from the collapse of a incredibly massive star.

[00:58:13]They are formed after the result of type two supernova, which is from the death of stars.

[00:58:19]>> We'll miss you when she leaves. Well, I'll miss you all, too.

[00:58:24]>> Our physics text said, "A star three times larger than the mass of the sun will become a black hole."

[00:58:28]Um I know that if it's greater than >> wait I'm blanking on the stars threshold for neutron star black hole >> is it 1.443 and yeah the toolman Oenheimer voloff limit okay no it's 1.4 yes you're right so 1.4 4 to 2.3.

[00:58:59]Yeah. Why did I think eight? So 1.4. So okay, if a star is greater than 1.4 solar masses, it becomes a neutron star. If a star is greater than 2.3 solar masses, it becomes a black hole.

[00:59:29]Why just 1.4 and 2.3? That feels imprecise. Well, I know there's exact specific numbers. Um, that's just a rough estimate. If you want to learn more, the 1.4 limit is called the the Chandra Secar limit. And the 2.3 limit is called the Tolkov Oenheim.

[00:59:45]It's the TOV limit. Tolman Oppenheimer Vulov limit.

[00:59:51]I wish Oenheimer was more famous for that stuff. Yeah, I mean it's cool that he also worked on like star stuff.

[01:00:01]>> Why give measurements in CPU hours?

[01:00:03]Wouldn't a faster CPU do it in less hours? Well, typically this can be machine dependent. Um, and so when you request for specific time, you request on a specific machine limit, right? Yes.

[01:00:27]>> Uh, >> let me try to get my next article out.

[01:00:35]So, the next article we're going to read is actually a little bit a little bit older.

[01:00:50]Sorry, I'm trying to load this up and it's not loading for some reason.

[01:01:00]>> Okay, I just got it to load.

[01:01:15]In the meantime, I might show you guys this animation again.

[01:01:25]>> You guys can admire this as I uh >> get the next article out. What is this called? How to trigger star formation.

[01:01:35]Supernova blast waves.

[01:01:39]Star Formation >> with Super Do Blast Waves. That's such a cool title.

[01:01:48]>> All right, let me pin this. Oop, replace P. Oh, okay. I think that worked.

[01:01:55]Um, >> all right.

[01:02:12]Are you a scientist? Yes, I am an IRA astrophysicist.

[01:02:22]Yeah. So I guess uh I don't typically study um supernova but in astrophysics you know there's a lot of overlap and I think this next article I think has probably the most overlap with the questions that I'm curious about. Um so yeah I'm super excited to read this. In the meantime this this animation is gorgeous. I I love this.

[01:02:46]This is probably my most favorite animation of all time. if uh Kim and I ever collab. So Kim and I collabed on Monday where we talked about our favorite space objects um or space images and we built a tier list and we were thinking about doing one with space animations and I think this one is honestly one of my favorites.

[01:03:09]Is it just me or the red dwarf and stars get brighter? I think it does because I think the image later is with a different telescope.

[01:03:19]I think it changes to a different telescope.

[01:03:25]>> Yeah. So, it it it appears to get brighter. That is >> all right.

[01:03:33]>> Oh, let me move chat back into the its correct corner.

[01:03:39]All right. Hot Shots. How to trigger star formation in the early universe by supernova blast waves. That's such a cool title, by the way.

[01:03:49]All right, let's read the initial mass function of stars. From a weirdo to perfect order, stars are formed via the collapse of interstellar gas into dense cores. The initial mass function of stars, which means the mass distribution of stars that form in a cluster environment like this. Wait, let's let's pull that up actually. Oh, oops, wrong one.

[01:04:12]>> Yeah, we can talk a little bit of Oh, whoa.

[01:04:17]the mass distribution of stars that this was the image that they pulled up by the way. That's such a cool image. It says the that is a really dense core of stars. Wow.

[01:04:31]>> It really makes you think like the sun is not special at all.

[01:04:36]>> That's so cool.

[01:04:40]>> All right, let's keep reading. Seems to be pretty universal. However, if we go back in time or red shift in a cosmological way of thinking, things aren't that clear anymore. Populations of stars which were formed very early after the Big Bang contain far less metals than in our direct neighborhood.

[01:04:55]This is because metals are formed in stars themselves and therefore the earliest ones had to get on without them. Yes, as I mentioned before, all the elements that aren't hydrogen and helium were literally formed in the center of the stars. So, if you think about the earliest stars, they had none of those heavy elements at all that could have been fused.

[01:05:14]Unfortunately, as often in astrophysics, the stellar population naming system is a bit confusing. The earliest stars and therefore the ones with the least metal content are called population 3 stars.

[01:05:24]So, these are actually theoretical stars. Uh we we still don't know if they exist. These stars would basically have only hydrogen helium. They would have no metals in the astrophysical sense.

[01:05:35]I guess another thing to add to the confusion is that in astrophysics, metals are literally just everything that is not hydrogen and helium. very different from the metals that you may be used to in your day-to-day life. The idea behind this generation scheme is that firstly huge population three stars are formed out of the big bang, explode a supernova and provide the grounds for the formation of the first population two stars. So population three stars are the origin of population 2 stars which have more metals and then population one stars which are like the sun that have plenty of metals inside them. These are then the second generation already containing a bit of metals but very few in comparison with nowadays population one stars like the sun. However, the details of the transformation from population 3 to population 2 are undergoing a lot of a debate challenged by observations of extremely metal poor population 2 stars.

[01:06:24]Interesting. Okay.

[01:06:28]Life into early gas clouds. To get an idea of how this could work out, the authors of today's paper run cosmological simulations with the Enzo code, trying to understand the transition from population 3 to population 2 star formation. To do so, they insert population 3 star particles in a complete metal-free gas environment like the conditions in the early universe. As shown in figure 1, these stars live and radiate away their photons, then explode in huge supernova and finally enrich their surroundings and metals. The blast wave of the supernova triggers turbulence in the neighboring gas structures and induces collapse. As the gas collapses towards the center of the gravitational structure, it fragments into several pieces of low mass in accordance with the observation of the oldest known stars to date. Okay, so let's take a look at this figure.

[01:07:13]Logarithmic density slices aparts of the evolution. The letters indicate important stages. So A is the halo in which the population three stars are placed.

[01:07:22]A >> oh here so they're here >> B is the dark matter halo which will be enriched and later on start to form population two stars. So there >> the see the population three star begins to shine. Okay so >> whoa yeah this thing is really freaking bright.

[01:07:44]>> Yeah. So red shift 20 is roughly when the first star is formed and then it goes to this and then D it explodes as a supernova.

[01:07:54]Wow, that's a very circular supernova. I guess the blast Oh, I guess it's very zoomed out. This is 50 par six. Okay, interesting. Um the blast wave collides with the neighboring halo.

[01:08:08]Oh, so this expands and it collapses with this part to form E.

[01:08:14]The right panel shows the temperatures.

[01:08:16]The image on the bottom right gives the logarithmic metalicity for time E. That is so cool.

[01:08:23]>> Yeah, it's very high temperature system for sure.

[01:08:32]>> So much light. Yes, globular clusters are too cool. I mean, oh, oops.

[01:08:38]This is so cool. The sun is special because I like it. Is very dear to me. I wonder if there's a star exactly like ours. Yes, there are. I mean, or stars that are the exact same spectral classification.

[01:08:51]>> I love looking at globular clusters with my telescope.

[01:08:55]I though I'm not a graduate in those fields, I love the cosmos. Thank you.

[01:08:59]Well, thank you so much for joining.

[01:09:00]That's exactly why I like doing these streams. Honestly, recently I've been getting a few emails and also a few comments from people saying that they decided to start an astrophysics course because of my channel or they became so interested in astrophysics that they decided to like volunteer at a local planetarium or actually some people who decided to start creating content as well. And every time I receive an email or a message or a comment like that, I just feel like I don't know. It I don't know.

[01:09:32]It just makes me feel so heartwarmed that something like space can really bring people together.

[01:09:39]Honestly, like space is the gateway science. It brings people into science.

[01:09:44]And whether or not you get interested into astrophysics and decide to stay in astrophysics or pursue another type of science, I think a lot of people have a very deep personal connection with space.

[01:09:55]I mean after all it is really the biggest thing you can study right.

[01:10:00]Hello millennium good seeing you. Hello Nebulas. Ah yes oxygen me breathing a metal. In fact we are breathing we are technically made of metals and we are always breathing metals. Actually there's a really funny XK CD comic about metals.

[01:10:20]>> Let me see if I can try to find it.

[01:10:29]Yeah, there we go.

[01:10:31]>> Music genres according to I guess this should be more like astrophysics.

[01:10:36]Astrophysics and nonastropist, pop, light, rock, metal, hip-hop metal, metal, metal, country metal, tatonic metal.

[01:10:51]Literally everything is in space. I mean that is true. We are in space.

[01:10:56]Call me a clanker. Lau.

[01:11:00]Call me a clanker. The way that I'm made of metals.

[01:11:05]We need to start naming more astrophysics exoplanets and stars. There are so many. Well, I heard that there's like a way to like purchase a star or like have it unofficially be named. Um, it's just easier to have it be based off of IDs and there are just so many stars.

[01:11:21]You could technically unofficially name a star.

[01:11:25]>> I think there it's a whole process if you want to actually have a a star name.

[01:11:30]We all metal heads.

[01:11:33]>> Actually, what's really funny, I don't think this group is metal, but ever since our collab, uh, well, Kim and I, we exchanged our like IRL social medias and stuff like that, and she was like sending me like music recommendations for this group called Star Set, right?

[01:11:48]And for me, if it's space themed, I automatically like it like 10 times more. I don't think it's metal, per se.

[01:11:55]I don't think it's metal because I think metal is very like like I'm just thinking like hard rocky, you know. Um, but but yeah, no, no, I've been listening to this group a lot recently because it's been it's been great. And they're space themed. They have like a song called Telescope, which I really like. All thanks to Kim's amazing music recommendations.

[01:12:16]If you know someone who discovered an asteroid, then you can officially name it. Oh, maybe maybe we should try to name an asteroid after after Z.

[01:12:25]>> The the the Orbeez asteroid.

[01:12:30]>> We're all metal heads. Technically, we are. Yeah. Is my typical romance metal?

[01:12:35]Wait, what exactly is the metal genre?

[01:12:39]Metal music genre.

[01:12:43]>> Oh, no. Loud distorted guitars.

[01:12:47]Okay. Yeah, I know. Rock.

[01:12:50]>> No, metal is a genre of rock, >> but it's heavier.

[01:12:58]No. So, okay. I I have not listened to or at least >> I I looked up metal genres and there's like a collage with here. Let me just show this. all these metal groups and I have not listened to any of these.

[01:13:16]>> I was wondering if like a system of a down would also be considered metal. I don't think so.

[01:13:25]>> Well, as an astrophysicist, everything is metal anyways. Well, no, no, no, no, no. System of a down is considered heavy metal. Okay. Okay.

[01:13:38]No, my chemical romance is rock.

[01:13:43]>> Okay, this is informative to me.

[01:13:48]>> Okay, great.

[01:13:50]>> Wow, I learned something new today.

[01:13:53]>> Sorry, that was such a tangent.

[01:13:56]System is metal. Yes. Okay. Okay, so I do listen to that group as metal.

[01:14:02]If I recommend Insomnium. Okay, wait.

[01:14:04]Hold up. It may be heavy for you, but it talks about how your sun's the sky.

[01:14:12]Okay, I will add that to my I added that as a tab, which means I will go through it later. Thank you for the recommendation. Yeah, I think um I'm kind of in my My Chemical Romance phase right now. Um I had a system of a down phase a while back.

[01:14:28]I think like these are this is the type of music that I listen to when I like really need to lock in.

[01:14:34]Yeah. So like when I'm really locking in like I listen to the black parade um by my chemical romance and recently I started listening to like three cheers for sweet revenge. It's like the album with like the two people kissing on the front and then um system of a down um that whole album with uh toxicity aerial pogo the pogo stick one it it's all great. It's all great. Sorry for those of you who aren't uh fans of System Down, but anywh who it is really good locking in music because it is so intense. Um it like gets your heart rate up. That and um the umamus sound.

[01:15:19]There are two wolves inside of me.

[01:15:21]System of a down/chemical romance music. Uma music.

[01:15:29]>> Oh, let's see.

[01:15:33]Kellian, they have a song with this Kepler space telescope. Okay, I'm gonna save that, too.

[01:15:39]>> This is all great. Thank you so much.

[01:15:40]I'm gonna have to make a new playlist.

[01:15:44]>> One of the Twilight soundtrack stars has Neutron Star. Okay, Twilight's neutron star collision.

[01:15:51]Wait, in the meantime, let me also look up System of a Down album.

[01:15:56]Uh, what's the one with them?

[01:16:01]Toxicity is the name of the album. I was like, it looks like the Hollywood sign.

[01:16:05]Yeah, that album is really good.

[01:16:08]What do you think of the Grand Tac base taste? Okay, bass taste. Okay. Okay. Okay. I was going to say like I I feel like, you know, sometimes I feel like cutesy anime music to get my spirits up and sometimes I feel like raw anger, rage, you know.

[01:16:32]There are two wolves inside of me.

[01:16:34]Please, I need I need a meme version of that. Maybe I'll make something like that. Hello, Tylerol. Sorry, we're going off on a bit of a tangent to talk about our music taste.

[01:16:45]The Grand Tac, you mean the Grand Tac hypothesis. So, for those of you who don't know, and I had to Google this real quick just to get this completely correct, proposes that Jupiter formed at a formed at a distance of 3.5 AU from the sun, then migrated inward to 1.5 AU before reversing course due to capturing Saturn in an orbital resonance, eventually halting the Earth's current orbit. Um, I unfortunately don't know that much about this theory, unfortunately. Um though I would love to read more.

[01:17:23]Would you be a fan of bands that combine them? Hannabe and Baby Metal. I love Baby Metal. I can't believe I literally just forgot that they existed. Yeah. No, I like their uh Give Me Chocolate song.

[01:17:34]I mean, I that's probably their most famous one, but that's such a good song.

[01:17:37]Okay, actually chat, if you have recommendations for um for songs, please let me know.

[01:17:45]Jupiter formed it. Okay, let's see this.

[01:17:50]>> So, it went in towards 1.5 AU and then reversed course and went outwards.

[01:17:55]That's so cool.

[01:18:02]>> Oh, there's like a lot of different reasons why this could have occurred.

[01:18:06]Alternatives jumping. Okay, I need to know what the jumping Jupiter scenario is. Z versus unskippable Wikipedia title impossible challenge evolution of a giant planet migration described by the nice model in which an ice giant is scattered inward by Saturn then ejected by Jupiter causing their semi-maajor axes to jump and thereby separating their orbits.

[01:18:35]That is so cool. I actually don't know anything about this. Thank you so much for bringing this to my attention. I unfortunately don't think um I I don't know too much about this hypothesis to make a judgment, but I think it's pretty cool.

[01:18:52]Yunha has a Oh, K-pop singer. Oh, I do like K-pop. Oh, yeah. I I listen to all the time. I also have a CD from Swiss as well. Stellar stellar. And well, I also did the violin cover, so you guys know I'm already fan. Yha.

[01:19:11]She was nicknamed the Oriccon Comet for her success on the Japanese music chart.

[01:19:16]>> Oh my gosh, she literally has a song called Comet. I will have to check that out. Thank you for the great song, Rex, guys. actually um you know what my favorite song was for a while when I was um when I was actually this was not when I was first getting into YouTubers but I remember I was watching more YouTubers during this period of time because of co and there's this song called Astrogirl by which was by Sana who like graduated but I listened to this song so much it became like my most played song of the year like within the span of like a week like I literally just had it on loop. It is such a good song.

[01:19:57]Red shift says the best. Yes, I agree with that sentiment. Snail's House is also a very goated uh producer.

[01:20:06]Sorry, that was such a tangent from the article, >> but thank you for bringing all of this music recommendation to my suggestion.

[01:20:17]>> Yippee.

[01:20:19]>> Fauna. Yeah. No. No. I I I loved I loved her content and I loved how she was so space themed and everything >> just before she announced graduation.

[01:20:30]Yeah, girl was also such a good song too.

[01:20:35]Yeah, but the all the songs that snails house makes are also really great. 07.

[01:20:41]Yeah.

[01:20:42]Sorry, this was such a tangent from us look oh whoa from us literally looking at super cool simulations of stars dying and we literally went into the discussion of how everything is metal including Z's music taste. Um so yes all right so let's keep on reading surprising diversity among the early birds. So where we left off was that we just saw how a population 3 star which is one of the earliest stars with very few metals which is not hydrogen or helium formed started lighting up which is shown here died and created a supernova and that supernova bubble expanded to then interact with the second uh halo region here um to form a second generation of stars. Okay, so let's take a look at this. Surprising diversity amongst the early birds as known from cosmology. The buildup of the cosmic web is dominated by dark matter and dark energy. Therefore, the behavior of the berionic matter, which is the essence of all visible objects in the universe, follows the clumping and motion of the dark matter around it. The gas falls in so-called dark matter halos, which gravitationally dominate all gas, stars, planets, and so on in their direct surrounding.

[01:21:52]The enormous blast waves ejected by pop three supernova hit these halos and influence the gas inside them. Thus, to get an idea of much matter is how much matter is influenced in their simulations, the authors check what which halos are in the contaminated area around the exploding stars. The two supernova and the affected dark matter halos are shown in figure 2. So, let's take a look here. The top panels show the cumulative density and the metalicity in the line of sight for two population three stars which exploded in the simulation >> for two. Okay, so the two stars I think are these two.

[01:22:28]The color circles correspond to the places of enriched halos. So it the the the depth of those stars reached those places. The bottom panel shows the logarithmic density. Oh, so they zoomed into the yellow and purple circles here and they showed what happened to the surrounding region after the deaths of these very early stars. The right supernova has a lot more neighboring dark matter halos and thus enriches more material. Yeah, there's a lot more stuff going on here.

[01:22:56]Okay, let's see what they found. Oh, there's a video. Okay, that's so cool.

[01:23:01]Most interestingly, these affected halos end up with extremely different metalicities.

[01:23:06]The 0.001 to 0.01 the solar metalicity.

[01:23:12]So that's almost a factor of three factor of two.

[01:23:16]Well, 10^ the two that is. Even if this channel, the enrichment of gas via only a single supernova is probably not the dominant process by which population 2 stars are formed, it is very interesting to see a huge diversity in the outcome and might give rise to a transition of the early IMF to the very uniform IMF we see today. So the start of this article is talking about the initial mass function which is describes the mass distribution of stars in the universe or within a system like a star cluster like the one shown here.

[01:23:49]And so we have to understand how these very early stars formed because the material from the deaths of those stars is then recycled back into this next generation of stars. So let's take a look at this animation because Oh, that's so cool.

[01:24:10]>> Nice. Nice.

[01:24:12]Okay. Wait, do they have time?

[01:24:16]Okay, they have red shift on the top and the cosmic age on the bottom. Okay, so everything's coalesing together. So the first for stars tend to form around red shift 20. So here, okay, so structures are beginning to form.

[01:24:34]Oh, so that's the first star being formed. Okay, I guess it formed around here.

[01:24:39]And because of the death, there was a supernova bubble and the metallicity.

[01:24:43]So, those metals are expanding out and enriching the surrounding region.

[01:24:51]>> This is so cool, guys.

[01:24:53]>> Oh my god.

[01:24:55]>> What's going on? Oh, it's zooming in.

[01:24:57]It's zooming in. It's zooming in.

[01:25:00]Okay. And then another star dies. And that material is getting ejected out.

[01:25:03]And so the metals are going out again.

[01:25:06]We're zooming in again.

[01:25:11]That material is sapping into this.

[01:25:19]>> Okay.

[01:25:20]>> Okay. Okay. So, it formed another star.

[01:25:25]>> Oh.

[01:25:29]>> Okay. So, we're slowing down substantially again.

[01:25:36]And then we're really zooming into this one, I think.

[01:25:41]>> Or or no, it's radiating outwards. It's radiating outwards, I think.

[01:25:45]>> Oh, no. No, we're also zooming in. We're also zooming in.

[01:25:50]>> Wow. This This really spans a lot of scales.

[01:25:59]>> Until collapses zero years.

[01:26:04]>> Wow, that is super cool.

[01:26:06]Wow. Very metal indeed.

[01:26:10]>> Wow. She did a watch along of Interstellar with Crony and you could tell she knew she had a real interest.

[01:26:16]That is so cool. No, Interstellar is a great movie. I have to watch the Odyssey. I don't know if anyone in chat has seen it. I have to read the Odyssey, too. Um, wow. We're going to watch this again because I now that I kind of know what's going to happen, I I want to watch this again. I love when with simulations like you can really just like play around with videos. I mean a part of the analysis is really playing around with videos too. You can see how galaxies merge and come together. In this case you can see the formation and deaths of stars.

[01:26:49]I just love how the temperature goes up when the star is like formed. It just like shines so brightly. Yeah. Like that. And it just heats up the surrounding region and when it dies it just leaves this bubble in its wake.

[01:27:04]Wow.

[01:27:11]>> This is incredible.

[01:27:16]>> It just really comes to show how dynamic the universe is. Yeah. And there's another star death there.

[01:27:25]>> Wow. I think out of the three that we read today, I don't mean to be biased, but I think this is definitely the coolest one.

[01:27:32]This article is also a little bit older.

[01:27:34]It's from 2015.

[01:27:40]>> And I mean, in the past 10 years, cosmological simulations have improved so much. Just imagine how much more detailed resolution that we can get on simulations like these today.

[01:27:50]Well, we don't even need to imagine it.

[01:27:51]That's literally what's happening. We're able to zoom in to really tiny levels even 10 years ago. And today we can go even further.

[01:28:06]Wow.

[01:28:09]Pretty cool animation. Yeah. No, this is great. I I'm glad that they included a video in this Astrobite. I think this is actually the first Astrobite I've seen that has had an embedded video.

[01:28:23]>> Wow. Thank you, Britain Smith.

[01:28:26]Well, the author of this is Tim Leenberg, PhD student in the department of earth and planetary sciences at ETH Zerk. Cool.

[01:28:37]Wow, this is super cool. What is used to make these simulations? Well, this was used make uh this was with the YT package which is commonly used to analyze simulations. It's a Python package. It allows you to open the different output files and create maps and projections.

[01:28:55]Someone asked, "What is your shadow arm?

[01:28:58]What is your favorite song of all time?"

[01:28:59]Actually, I'm curious if chat if you guys have recommendations because I've been getting a lot of good recommendations today.

[01:29:06]This is very embarrassing, but I think my favorite song of all time may have maybe this one. It's called Wonder Pop.

[01:29:13]Um, I don't know why, but this song just gives me so much energy. Um, I have it downloaded on my iPod. I have it download on my phone. I have it downloaded on literally every single music playing device I can. It's like literally my version of like Hello World. Like if I get something new to listen to music on, like that is the first song I save. Um it is in almost all of my Spotify playlist. It's such a good song. Um it is very high energy. It's a great song to walk to, to run to, to do work to. It's just truly the most multiaceted song you can think of. Here, I'll I'll move chat a little bit closer.

[01:30:05]>> IRL is way slower. I mean, yes. I mean literally the x- axis of this this was showing the the time on the x- axis >> like this is spanning >> 250 million years so much slower in real life.

[01:30:29]>> What is used to make these simulations?

[01:30:31]Oh, not the uh projections. Um here they're using the Enzo code which is a hydrodnamical code. In most of the cases they're kind of like a giant PTE solvers. Um they basically evolve physics equations of hydrodnamics and physics.

[01:30:51]Um so this is the website.

[01:30:58]So oh I realized chat's in the way.

[01:31:03]Yeah, it's great.

[01:31:09]Super cool. Well, that was our last and third article of the day. I think this one has to be my favorite. Let me know what you think your favorite was, but I think this one was probably my favorite.

[01:31:20]And yeah, I think it's about time to wrap it up. Let me see when my next oop when my next stream will be.

[01:31:29]Um, I think it'll be next week.

[01:31:32]So, yes. So, my next stream will be next Thursday.

[01:31:38]So, I will be averaging one stream a week for the next two weeks. So, there will be one stream next Thursday and then the other stream will be next Wednesday. Um, and then the one next week is actually a collab with, drum roll, please. Oh. Oh my god.

[01:31:59]Not drum roll please. Oh my god. My phone fell off the water bottle. I Oh my god. That was actually kind of scary.

[01:32:05]I've been dropping my phone everywhere that like the upper right corner has like cracks all over it.

[01:32:13]Um it is with drum roll please. Silent drum roll. It's with Fi. Oh my god. I haven't collabed with Fi in so long. Um, oh actually I realized that uh maybe I should do aum.

[01:32:30]Oh, I have to update this to include the new purpose. Keep forgetting to do that.

[01:32:35]Um, but yeah, I'm part of a group and Fi does cell biology and immune system stuff. Um, but what we're actually going to talk about is about our favorite science communicators. So, we're going to be talking about Neil Degrass Tyson and other people that you may enjoy.

[01:32:50]Phone and water bottle. My water bottle also has a crack in it, guys.

[01:32:55]I No, literally, I need to get like a new water bottle, a new phone case, a new phone.

[01:33:01]I just need to get a new charger because the other day like the wires started showing out like the the the metal part of the wire started showing out of it.

[01:33:08]So, I had to get electrical tape.

[01:33:13]Oh, best of luck to Shadow Arm Fi Collab. I hope you get a tough case for your phone. Yeah. No, I typically get these like Caseify cases. They're actually really nice and super cute. I got a new case, but it arrived literally right after I left for Europe.

[01:33:30]So, I had it mailed like to the States and then literally the day after I left, it arrived and I was like, "Bro."

[01:33:38]So, I will be replacing my phone case with that as soon as I'm back in the States.

[01:33:46]Yippee. Yeah. I know. I'm so excited for the for the collab with Fi. It's going to be great.

[01:33:54]>> Oh, I just realized that I have 10 free gift memberships to give out this month.

[01:34:01]>> Um, well, I think we should do five today and maybe five next time. Does that sound like a plan? And then I'll wrap things up. All right, drum roll, please.

[01:34:15]A bit of a silent drum roll because I don't want my phone to be knocked over.

[01:34:19]>> All right, let's see.

[01:34:27]>> Yay! Congratulations, Nebless, Lollisters, Pedang Sakti, and Kuso Banoada and Pacne for receiving gift memberships. So, if you aren't already, go ahead and join the Discord. Um, and we have a special membersonly chat and channel, and I also send like a weekly subscription thing to showcase some IRL updates.

[01:34:56]>> Yippee.

[01:35:00]All right, I think that is a great way to end the stream. Um, I will keep you guys updated on how things go. Thank you all for the music recommendations.

[01:35:09]I love doing Astrobite streams and I hope you guys enjoy them, too. I honestly learned a lot. That was actually so cool.

[01:35:17]>> Oh, all right. I will see you guys and then Oh, okay. Let's Let's figure out who to raid. Let's see who's streaming.

[01:35:24]Um, >> wait, someone's Rockettology is playing Kerbal Space Program. Should we Should we raid that?

[01:35:35]>> I think that I think that's the move.

[01:35:39]So, if you're on the YouTube, go on, head over to the Twitch. Oh, >> did that not work?

[01:35:47]>> Yes.

[01:35:48]>> And then we're going to set up the raid.

[01:35:51]>> And then just copy and paste that message and we will be on our way. All right, I will see you guys in the next one. Till then, stay safe, stay healthy, stay happy, and stay excited about star death. All right, I'll see you guys later. Bye-bye.

[01:36:12]Bye-bye. Bye-bye. Bye-bye. Bye.

[01:36:40]Though I'm trying not to wonder, gazing up into the sky, though my heart has not recovered. Take it one step at a time.