The Flaming Skull Nebula SH2-68. Cool name, Hotter Science!

[00:00:00]The Flaming Skull Nebula, SH2-268, and a ton of science.

[00:00:06]Welcome to Sedi Astro.

[00:00:11]>> [music] >> So, I did just get at 50 hours of integrations, 200 15-minute exposures split fairly evenly across hydrogen, oxygen, and sulfur. It was 18 and 1/2 hours of integration for hydrogen, 18 hours of oxygen, a little over 13 hours for sulfur. I just want to show you it is it is a fairly dim object. Here's just the Here's just a single frame for hydrogen, single frame for oxygen here, and a single frame for sulfur. So, let's go ahead and look at the stacked masters.

[00:00:49]Now, these have already had a little bit of work done to them so I could stretch them a little bit harder, but they're still still linear.

[00:00:58]And for a hydrogen, you absolutely see this really cool C-shape here or extra lobe, and then this commentary-like structure streaming off of it.

[00:01:10]For oxygen, on the other hand, it really is just the central ball, and then a much much fainter kind of outer lobe here. And then sulfur, there's some nice distinct structure in here, kind of on this one limb, and then maybe a little bit more down here, but other than that, it's kind of just diffused through there. And overall, pretty pretty dim. So, I did use Perfect Pallet Picker, and I did come up with both the Forax and the Realistic 2 views, and I really like the Forax. There's more like structure of color that you could see through here versus the Realistic 2.

[00:01:45]Uh so, that's the that's the one I really went with. I did do pre-stretching of the hydrogen, oxygen, and sulfur instead of letting Perfect Pallet Picker do it so I could make it a like a brighter image. Uh so, this was the the brighter Forax palette. But then, you know, just kind of hitting it with curves, hitting it with a little selective color correction in here to make some of the blues and yellows pop a little bit more, blending in a little bit of hydrogen as luminance.

[00:02:10]And then, uh, again, just more curves and stretching.

[00:02:14]Trying to get it to something that I really liked here.

[00:02:18]And then, finally, putting the stars back in. So, this is kind of where I ended up with, uh, SH2-68, the Flaming Skull Nebula. There's still this, uh, nebulosity that goes off, you know, off into the right here. We're going to talk a lot more about that here in a second.

[00:02:33]So, I did go hunting through the literature for this particular object to see what was out there. And, short answer, not a whole lot of nothing.

[00:02:40]Which is kind of amazing because this is one of the confirmed planetary nebula that have interstellar media interaction. That's what's forming that comet-like tail. So, I really only found like four sources, and really it's only two. So, I just listed them out here in my project, but I want to grab some excerpts out of them. So, the first one has to do with the the proper motion of the progenitor star. And the progenitor star is actually this really, really blue one right here in the middle.

[00:03:10]And you can see I rotated the paper's findings to be in the same orientation as my image here. And if I zoom way in, now you can really see how it lines up.

[00:03:20]We have these bright stars around it here, are these same ones over here.

[00:03:25]And the progenitor star is actually moving, uh, to the left in my image. And over 50 years, so this is looking at 50-year time span here, you can see that that progenitor star moved from this location slightly left.

[00:03:40]And, uh, when this paper was written back in 2002, they had a a decent pin on how fast that motion was.

[00:03:47]Uh, and then there was a paper by Fast that really pinned down the the motion a lot better to get some really accurate tangential velocities. And it's going 125 km per second to the left in my image, which I think is really cool. You know, you could actually pin down and see the star moving over the years and derive an exact speed it's actually moving in there, which actually is in the opposite direction of where all this comet-like structure is.

[00:04:14]So, as this whole thing is plowing to the left, it's interacting with a bunch of interstellar media that's, you know, neutral hydrogen where you can't see it on the on the left here, and it's streaming out this this broad comet-like structure.

[00:04:30]And again, if we look at the stretch of the hydrogen solely, you could see this structure up in here. Or if we just auto stretch the compiled image here, too, you could you could really see this red structure where that's the that's commentary stream. And that's actually been noted as well, again back in 2002.

[00:04:50]Um this was the image of it then, where they discovered this commentary-like tail.

[00:04:56]Again, rotated the paper so it aligns with with my image here, and you could see the the comet structure is almost identical to what I'm showing here. And then the more modern fast radio search of this particular area, really what you're looking for what they were looking for was bubbles, and that's the central bubble here. But over in the upper right here, this lobe that's going out, that's actually this tail here in radio.

[00:05:25]And you could see it's like that same exact shape and direction here for this upper lobe. And again, that's just getting pinched by this interstellar media which is neutral hydrogen, kind of pinching out the structure as, you know, the progenitor star in the nebula is kind of plowing to the lower left.

[00:05:44]Now, the other thing SAS Pro allows you to do is actually get um photometric surface brightnesses of your objects. Um so I've already plate solved this and fetched the stars and computed the zero points. And for hydrogen, uh you can see how well the uh fit line is for our zero point uh calibration across many orders of magnitude here. So we could actually go in and pick an area to measure. And this is uh what I ended up doing. So let's go ahead and look at some of the dimmer coma structure that's out here.

[00:06:16]Uh we want to make sure we don't get in any stars because that'll actually make it appear brighter. And then we can go ahead and measure that that object. And that that surface area is a magnitude 22.2 uh per arc second squared.

[00:06:29]So very dim even in this common structure. And since there really wasn't a whole lot in the literature about actual brightness, in fact nothing about brightness in any of the literature I saw, um since I did have 50 hours of integration, I figured it'd be great if I actually uh took a whole bunch of surface brightness measurements and uh write a technical paper. So that's absolutely what I did. I'll have a link to this paper in the video description as well. It's, you know, the the surface photometry of SH2-68.

[00:07:02]I have a little abstract in there, uh introduction as to what the planetary nebula is.

[00:07:09]My actual end result image of the the deep narrow band composite of it.

[00:07:14]All my acquisition details here.

[00:07:17]The photometric calibration approach that SASPro uses.

[00:07:22]And then and then my results. So I have uh four different measurements for hydrogen alpha, two for oxygen, two for sulfur, and then the surface brightnesses and magnitudes per square arc arc seconds.

[00:07:36]And the tail and the fainter outer halo of oxygen are very very faint. 23.7, 23.3 extremely faint areas.

[00:07:48]And then a little description of that in there.

[00:07:51]And then I also have a discussion of the tail direction and optical signature of that interstellar medium interaction.

[00:07:58]A little conclusion area and then some references for some of the other data in here.

[00:08:03]Like the distances and proper motion speeds. Then I have all my zero point calibration curves.

[00:08:10]The locations of all the samples measurement.

[00:08:18]And then a final bit on the tail direction for both what I showed earlier against the the fast radio telescope and then Kerber's optical image of it back in in 2002.

[00:08:29]I've also updated AstroBin with my Flaming Skull Nebula with a commentary-like tail. It does have a mouse-over zoomed in portion of it so you could see the central core there really nice.

[00:08:40]I have all my acquisition details here again and then some of these discussions that I was talking about in the video about the proper motion, where the progenitor star is, and a link to the technical paper and some of the results and summaries of that.

[00:08:56]I've also submitted that technical paper to planetary nebulae and hash databases for inclusion in their databases for surface brightness.

[00:09:06]I've also updated my website steadyas.com under nebula.

[00:09:11]You're going to go ahead and find the Flaming Skull Nebula with a mouse-over zoomable. You can also click this and download the the main full image if you just want it. A little bit of a write-up here, link back to AstroBin and my technical paper, and again some of the results of that technical paper and the the commentary-like tail direction.

[00:09:31]Well, I hope this encourages somebody out there to go ahead and try their hand at a a dim object SH2-68. It is uh fairly southern uh for most of the northern latitude imagers out there, but if you're in the southern hemisphere, maybe a really good uh target or if you're equatorial, an excellent target for you. It'll be pretty much directly overhead this summer. And if anything, encourage you to go try to shoot something that's rarely imaged out during the summer months here because everybody's going to be imaging all those other very popular nebula. So, give it a go and um try something new this summer.

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