APOD: M27: Not a Comet (2010 Aug 26)

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APOD: M27: Not a Comet (2010 Aug 26)

Post by APOD Robot » Thu Aug 26, 2010 4:03 am

Image M27: Not a Comet

Explanation: While hunting for comets in the skies above 18th century France, astronomer Charles Messier diligently kept a list of the things he encountered that were definitely not comets. This is number 27 on his now famous not-a-comet list. In fact, 21st century astronomers would identify it as a planetary nebula, but it's not a planet either, even though it may appear round and planet-like in a small telescope. Messier 27 (M27) is an excellent example of a gaseous emission nebula created as a sun-like star runs out of nuclear fuel in its core. The nebula forms as the star's outer layers are expelled into space, with a visible glow generated by atoms excited by the dying star's intense but invisible ultraviolet light. Known by the popular name of the Dumbbell Nebula, the beautifully symmetric interstellar gas cloud is over 2.5 light-years across and about 1,200 light-years away in the constellation Vulpecula. This impressive color composite highlights details within the well-studied central region and fainter, seldom imaged features in the nebula's outer halo. It includes narrowband images recorded using filters sensitive to emission from oxygen atoms, shown in blue-green hues, and hydrogen atoms in red.

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Re: APOD: M27: Not a Comet (2010 Aug 26)

Post by owlice » Thu Aug 26, 2010 7:08 am

First seen on the Asterisk here; that thread contains another very nice image of this nebula without the nebulosity, too (in addition to other fine images of other things).

"fainter, seldom imaged features" indeed!! I think this is the first image I've seen that showed the outer halo. Great picture, excellent write-up.
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Re: APOD: M27: Not a Comet (2010 Aug 26)

Post by orin stepanek » Thu Aug 26, 2010 11:49 am

APOD gets some neat photos of planetary nebulae. And they're all different.
http://www.astro.washington.edu/users/balick/WFPC2/ 8-)
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APOD: M27: Not a Bird, Not a Plane

Post by neufer » Thu Aug 26, 2010 12:32 pm

Art Neuendorffer

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Re: APOD: M27: Not a Comet (2010 Aug 26)

Post by emc » Thu Aug 26, 2010 2:04 pm

orin stepanek wrote:APOD gets some neat photos of planetary nebulae. And they're all different.
http://www.astro.washington.edu/users/balick/WFPC2/ 8-)
Hi Orin, Nice to see you’re still on the job!

Today’s APOD brought to mind our Sun’s finite life window, be it well past my time span comprehensibility.

Wonder what shape our Sun will take? Another dumbbell or maybe a majestic dragon…

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Re: APOD: M27: Not a Bird, Not a Plane

Post by emc » Thu Aug 26, 2010 2:05 pm

neufer wrote:ImageImage M27: Not a Comet
Image

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Re: APOD: M27: Not a Comet (2010 Aug 26)

Post by bystander » Thu Aug 26, 2010 2:22 pm

emc wrote:Hi Orin, Nice to see you’re still on the job!
Hi, Ed! Good to know you're still with us!

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Re: APOD: M27: Not a Comet (2010 Aug 26)

Post by emc » Thu Aug 26, 2010 3:03 pm

bystander wrote:
emc wrote:Hi Orin, Nice to see you’re still on the job!
Hi, Ed! Good to know you're still with us!
Right back at ya’ bystander!

I feel like a dot of dust in an extremely eccentric Asterisk orbit exhibiting lots of lollygagging libration.

BTW – Thanks to you for bringing to my attention… I’m still amazed to have learned that our Sun is protecting us from a very hot gaseous interstellar cloud!

I have new appreciation for the Sun.

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Re: APOD: M27: Not a Comet (2010 Aug 26)

Post by orin stepanek » Thu Aug 26, 2010 3:07 pm

emc wrote:
orin stepanek wrote:APOD gets some neat photos of planetary nebulae. And they're all different.
http://www.astro.washington.edu/users/balick/WFPC2/ 8-)
Hi Orin, Nice to see you’re still on the job!

Today’s APOD brought to mind our Sun’s finite life window, be it well past my time span comprehensibility.

Wonder what shape our Sun will take? Another dumbbell or maybe a majestic dragon…
Hi Ed! I'm with bystander; I'm glad to hear from you also. 8-) When the sun goes out; and I hope that's a long ways off (a few billion years); I bet it makes a pretty planetary nebula. :lol:
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Re: APOD: M27: Not a Comet (2010 Aug 26)

Post by owlice » Thu Aug 26, 2010 3:15 pm

I'm not only glad to see you, Ed, but will admit to thinking of the exact same thing you (apparently, from the picture you posted,) did!

I feel so... so... so understood!! :D
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Re: APOD: M27: Not a Comet (2010 Aug 26)

Post by emc » Thu Aug 26, 2010 4:46 pm

orin stepanek wrote:When the sun goes out
Hi Orin, Thanks for the reply! “When the sun goes out” would make a good song title. Do you think they will have changed the name “planetary nebula” to something else by then?

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Re: APOD: M27: Not a Comet (2010 Aug 26)

Post by emc » Thu Aug 26, 2010 4:48 pm

owlice wrote:I'm not only glad to see you, Ed, but will admit to thinking of the exact same thing you (apparently, from the picture you posted,) did!

I feel so... so... so understood!! :D
Hi owlice, Thank you! Glad to have shared a thought with you! One never knows exactly what will be communicated by a picture without words especially when it’s not known whether key background information is shared… but I reckon that’s part of the venture.

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Re: APOD: M27: Not a Comet (2010 Aug 26)

Post by orin stepanek » Thu Aug 26, 2010 10:47 pm

emc wrote:
orin stepanek wrote:When the sun goes out
Hi Orin, Thanks for the reply! “When the sun goes out” would make a good song title. Do you think they will have changed the name “planetary nebula” to something else by then?
No! :? I don't know! :? :mrgreen:
Orin

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Re: APOD: M27: Not a Comet (2010 Aug 26)

Post by Ann » Fri Aug 27, 2010 4:00 am

Planetary nebulae are just not my thing, because they frustrate me so, colorwise. :evil:

But thanks for posting the Superman shield, neufer! That cheered me up. I used to be a real Superman fan, particularly when the S-man went flying with Lois... and I agree that that planetary nebula does seem to have a sort of "S" in it. Maybe Lois is in there too, if you look hard enough. Okay, find Lois in it for me and I promise I'll like this particular planetary!

emc wrote:
Do you think they will have changed the name “planetary nebula” to something else by then?
Hopefully! (Although I'm not altogether sure who "they" will be, the ones who will change the name of the cast-off glowing solar envelope by the time the Sun casts off its envelope and makes it glow.)

But "planetary nebula" is an embarrassing name, a bit like calling the Earth "the sun of the universe". The term is a remnant from a time when people didn't know any better.

Ann
Last edited by Ann on Fri Aug 27, 2010 8:12 pm, edited 2 times in total.
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Re: APOD: M27: Not a Comet (2010 Aug 26)

Post by DavidLeodis » Fri Aug 27, 2010 8:04 pm

I wonder why nearly all of the halo is to one side (at least in this view) :?: