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KJPN8 Polypolar Planetary Nebula

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#1 schmeah

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Posted 01 July 2020 - 10:42 PM

KJPN8 is a bizarre polypolar planetary nebula in Cassiopeia. It is rarely imaged which is surprising given its close proximity to the Bubble Nebula. In fact, many have it in their field when the capture the Bubble Nebula but don't recognize it because it is so faint. The strange structure is thought to be the result of multiple periods of ejectate by a rotating binary core over time.

 

This is its location in a widefield shot of the Bubble Nebula:

https://pbase.com/ds...image/166005925

 

Thanks for looking. Comments and critique are always appreciated.

Derek

 

https://pbase.com/image/170841084

 

KJPN8 HaLLRGB small.jpg


Edited by schmeah, 01 July 2020 - 11:04 PM.

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#2 schmeah

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Posted 02 July 2020 - 06:25 AM

D37100F6-F2F6-44F4-BF5E-13942C4E6F94.png


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#3 Epox75

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Posted 02 July 2020 - 07:19 AM

I noticed its structure while processing a wide field of the Bubble area I recently took. I thought "I have to plate solve this" but then I forgot to do it... So thanks for the information and for reminding me how forgetful I am lol.gif 

Nice picture by the way, I like the purple tone of the PN. 



#4 Ron (Lubbock)

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Posted 02 July 2020 - 07:29 AM

Thanks for sharing this image and information.  My field of view is not large enough to find this one, and I did not know it existed.  I have to wonder how people confirmed it was a  PN - from emission wavelengths, I guess?  Is that bright star actually the central star that produced the PN?   It really does look like yet another patch of H-alpha.



#5 schmeah

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Posted 02 July 2020 - 12:03 PM

I noticed its structure while processing a wide field of the Bubble area I recently took. I thought "I have to plate solve this" but then I forgot to do it... So thanks for the information and for reminding me how forgetful I am lol.gif 

Nice picture by the way, I like the purple tone of the PN. 

Thanks! The color is an artistic rendering, having added various degrees of Ha to the Red and Blue channels. On the few images I have seen, it appears redder, and the OIII component is quite weak.

 

Thanks for sharing this image and information.  My field of view is not large enough to find this one, and I did not know it existed.  I have to wonder how people confirmed it was a  PN - from emission wavelengths, I guess?  Is that bright star actually the central star that produced the PN?   It really does look like yet another patch of H-alpha.

Thanks Ron. And thanks for asking the question about the central "star". In the few images I have seen, it appears to be more star-like, but I wonder if this has to do with post processing on the assumption that it was a star. I suspect that even if there is a star underlying, that the slightly oval patch is indeed more nebula. I say this because it does not appear on the luminance stack (or is punctate if present) but is obvious on the Ha stack. And the color clearly matches that of the nebula itself rather than any of the RGB stars.

 

Derek



#6 astroian

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Posted 03 July 2020 - 08:06 AM

That’s a really nice capture. I like the colour combination as well.

If you look up the object on SIMBAD you will find a list of all the papers that reference this object. Some will just have included it as part of a survey, some may have actually studied it. You might find more info on the central star.

It’s nice to see others taking images of obscure PNe 😀

Cheers, Ian

#7 schmeah

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Posted 03 July 2020 - 10:43 AM

Thanks for sharing this image and information.  My field of view is not large enough to find this one, and I did not know it existed.  I have to wonder how people confirmed it was a  PN - from emission wavelengths, I guess?  Is that bright star actually the central star that produced the PN?   It really does look like yet another patch of H-alpha.

 

 

That’s a really nice capture. I like the colour combination as well.

If you look up the object on SIMBAD you will find a list of all the papers that reference this object. Some will just have included it as part of a survey, some may have actually studied it. You might find more info on the central star.

It’s nice to see others taking images of obscure PNe 😀

Cheers, Ian

Thanks Ian! So your and Ron's comment regarding the central "star" got me thinking more about this. When I saw the few other images of this, also captured in combined narrowband and broadband,  it certainly had a star like appearance in terms of brightness / sharpness and color, which was distinct from the nebula and more like other typical stars in the field:

 

https://3.bp.blogspo...cB/s0/KjPn8.jpg

https://www.astrobin.../full/378134/0/

https://astrodonimag...anetary-nebula/

https://www.cloudyni...extended-lobes/

 

So I began to wonder why the central star in my image had a muted appearance (though Josh Smith's example above was a bit similar) with the same color as the nebular structure. When I look back at this, on my linearly scaled but otherwise unprocessed luminance and Ha stacks, the star is very prominent in Ha and barely present in luminance as, and opposite in every other star in the field where as expected the luminance stars are more prominent. A crop of these stacks are attached below.

 

And an excellent discovery paper describes a small Ha core of 3.6":

https://iopscience.i...09801/fulltext/

 

So I believe that in fact we are not looking at a central star, or at least it is hidden beneath the Ha core. I can't explain why other's images suggest otherwise.

 

Luminance

KJPN8core (2).png

 

Ha

KJPNcoreHa (2).png



#8 dan_hm

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Posted 03 July 2020 - 11:55 AM

Really cool picture, Derek. I don't think I've ever seen it imaged on its own before. Glad you were able to get a full image out of this very brief period of clear weather we had. I hope I'm proven wrong but it looks like we are in for a really crappy season here. 



#9 astroian

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Posted 04 July 2020 - 05:25 AM

Derek,

The small size of 3.6” is going to look pretty much stellar for most imagers. Combine that with the expectation that a PNe has a central star and you can see why folks would process it as such.

Having read the paper you reference I would agree that what we’re seeing here is nebulosity at the core rather than the central star. It’s interesting that they don’t talk about the central star but the core. Most studies of PNe will say something about the CS if it’s visible.

The authors suggest it is a young PNe so perhaps the central star is still surrounded by expanding layers of what was the stars inner layers that were outside of the stars core (idle speculation on my part, so take that with a large amount of salt!).

Cheers, Ian

#10 schmeah

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Posted 04 July 2020 - 08:36 AM

Really cool picture, Derek. I don't think I've ever seen it imaged on its own before. Glad you were able to get a full image out of this very brief period of clear weather we had. I hope I'm proven wrong but it looks like we are in for a really crappy season here. 

Crappy season? In NJ? The mecca of astroimaging?

 

 

Derek,

The small size of 3.6” is going to look pretty much stellar for most imagers. Combine that with the expectation that a PNe has a central star and you can see why folks would process it as such.

Having read the paper you reference I would agree that what we’re seeing here is nebulosity at the core rather than the central star. It’s interesting that they don’t talk about the central star but the core. Most studies of PNe will say something about the CS if it’s visible.

The authors suggest it is a young PNe so perhaps the central star is still surrounded by expanding layers of what was the stars inner layers that were outside of the stars core (idle speculation on my part, so take that with a large amount of salt!).

Cheers, Ian

Thanks Ian. Sakib Rasool pointed me to this article. In it they report that the central star was “finally revealed” by the Hubble Wide Field Camera 2 beneath the compact nebula core which was itself resolved into an elliptical ring. So yes, it would appear that it is the nebular core, not the central star that we are seeing. I think I’ll need to be very careful before I sharpen those central PNe  “stars” In the future :)

 

https://iopscience.i...09122/fulltext/



#11 astroian

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Posted 05 July 2020 - 10:27 AM

Just goes to show we all have to be careful about what we think we’re seeing. Just consider the name “Planetary nebula” and what we now know them to be 😀

Cheers, Ian

#12 Ptarmigan

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Posted 05 July 2020 - 11:25 AM

Nice image! cool.gif waytogo.gif

 

I like seeing obscure objects imaged. cool.gif waytogo.gif


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#13 Jim Thommes

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Posted 05 July 2020 - 09:09 PM

Excellent image Derek and excellent discussion on the "central star".

 

I had imaged the bubble in Ha, OIII and LRGB last year (2019) and actually annotated KJPN8 in my annotated image. It came out well in the Ha data; very weak (if anything) in OIII. Interestingly, I did a starless combine of Ha and OIII and then added LRGB stars. Thus the Ha "core" of the KJPN8 central star was removed in the starless process and the LRGB star was inserted. The central star in my process turned out to be dim as you noted in your luminance crop.

 

I got a very similar outer structure to KJPN8 as you did, but a small and dim central star (as well as a few more distracting stars in a richer luminance star field like in your luminance crop).

 

Great work, well done.


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#14 Bloated Star

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Posted 05 July 2020 - 11:02 PM

You should be proud of this one. Truly an outstanding image.
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#15 schmeah

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Posted 07 July 2020 - 05:15 AM

Excellent image Derek and excellent discussion on the "central star".

 

I had imaged the bubble in Ha, OIII and LRGB last year (2019) and actually annotated KJPN8 in my annotated image. It came out well in the Ha data; very weak (if anything) in OIII. Interestingly, I did a starless combine of Ha and OIII and then added LRGB stars. Thus the Ha "core" of the KJPN8 central star was removed in the starless process and the LRGB star was inserted. The central star in my process turned out to be dim as you noted in your luminance crop.

 

I got a very similar outer structure to KJPN8 as you did, but a small and dim central star (as well as a few more distracting stars in a richer luminance star field like in your luminance crop).

 

Great work, well done.

Thanks Jim. That’s interesting. What was the color of your central star? 
 

Derek




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