APOD: The Great Nebula in Carina (2017 Jun 13)

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APOD: The Great Nebula in Carina (2017 Jun 13)

Post by APOD Robot » Tue Jun 13, 2017 4:08 am

Image The Great Nebula in Carina

Explanation: In one of the brightest parts of Milky Way lies a nebula where some of the oddest things occur. NGC 3372, known as the Great Nebula in Carina, is home to massive stars and changing nebulas. The Keyhole Nebula (NGC 3324), the bright structure just to the right of the image center, houses several of these massive stars and has itself changed its appearance. The entire Carina Nebula, captured here, spans over 300 light years and lies about 7,500 light-years away in the constellation of Carina. Eta Carinae, the most energetic star in the nebula, was one of the brightest stars in the sky in the 1830s, but then faded dramatically. While Eta Carinae itself maybe on the verge of a supernova explosion, X-ray images indicate that much of the Great Nebula in Carina has been a veritable supernova factory.

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Re: APOD: The Great Nebula in Carina (2017 Jun 13)

Post by snuggs28 » Tue Jun 13, 2017 1:30 pm

Could it be possible we are watching a Globular Cluster being formed? 14,000 stars in the region.

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Re: APOD: The Great Nebula in Carina (2017 Jun 13)

Post by Chris Peterson » Tue Jun 13, 2017 1:47 pm

snuggs28 wrote:Could it be possible we are watching a Globular Cluster being formed? 14,000 stars in the region.
No, just the opposite- young star forming regions like this are short-lived, with the stars quickly dissipating because they're so weakly bound by gravity.

There is no evidence that globular clusters can still form. The formation of both globulars and galaxies are somehow related, and both apparently required conditions found in the early Universe which no longer exist.
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Re: APOD: The Great Nebula in Carina (2017 Jun 13)

Post by neufer » Tue Jun 13, 2017 3:07 pm


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Re: APOD: The Great Nebula in Carina (2017 Jun 13)

Post by MarkBour » Tue Jun 13, 2017 3:24 pm

A nice, dark image of the region. It makes the nebula look a lot like a few glowing embers of coal.

Too bad I can't easily travel to Prague to hear RJN's talk on June 30. I'm sure it will be inspiring!
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Re: APOD: The Great Nebula in Carina (2017 Jun 13)

Post by Ann » Tue Jun 13, 2017 3:25 pm

Chris Peterson wrote: There is no evidence that globular clusters can still form. The formation of both globulars and galaxies are somehow related, and both apparently required conditions found in the early Universe which no longer exist.
Globular clusters NGC 5053 (left) and M53 (right).
Source: http://www.skyhound.com/Fraternal%20Twins.html
Whether or not globular clusters can still form partly depends on how we define "globular clusters" in the first place. Very many of the old, classic globular clusters must have been extremely large and massive when they formed, but it is quite possible that some of them were not so massive.

At left you can see two globular clusters that are located close together in the sky, but it is only too obvious that one of them (M53) is much more massive than the other one (NGC 5053). It seems likely to me that these globulars were born unequal, and that NGC 5053 may never have been extremely massive.
Hodge's Cluster in NGC 6946. Source: Hubble/Keck/ S.Larsen?







Yes, but now check out young massive Hodge's Cluster in NGC 6946.
Yu.N.Efremov, V.L.Afanasiev, E.J.Alfaro, R.Boomsma, N.Bastian,
S. Larsen, M.C.Sánchez-Gil, O.K.Silchenko, B.García-Lorenzo, C.Muñoz-Tuñon, and P.W.Hodge
wrote about Hodge' Cluster:

Its photometric and dynamical masses were also estimated from these observations; both estimations provide similar values close to 106 solar masses. It was possible therefore to suggest that the cluster is gravitationally bound and that it resembles a young globular cluster, eventually to evolve into an old classical globular cluster. Its parameters fit those for giant young compact clusters, often
called super star clusters (SSC).
NGC 3293, a massive young cluster.
Photo: ESO/G. Beccari
I agree that young super star clusters (SSCs) are not identical to "classic" globular clusters, partly because extremely few SSCs were born as massive as the classic 10-12 billion-year-old globular clusters, and also because the young SSCs are not as metal-poor as classic globulars. But Chris points out an interesting possibility - perhaps the "true" globular clusters are the by-products of an early evolutionary phase of galaxy formation in the young universe. If so, no more globulars can ever form again, by definition. However, massive young clusters can still form.

No globular cluster-like clusters - and no clusters similar to Hodge's Cluster - can be found in the Carina Nebula, and there are no signs of anything nearly so massive forming there. The most massive-looking cluster in the area is NGC 3293, which is the extended blue object near the bottom of today's APOD. But NGC 3293 is a far cry from being a globular cluster.

EDIT: NGC 3293 is apparently "top-heavy", and therefore even less massive than it appears to be. See here and here.

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Last edited by Ann on Wed Jun 14, 2017 1:14 am, edited 2 times in total.
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Re: APOD: The Great Nebula in Carina (2017 Jun 13)

Post by DrC » Tue Jun 13, 2017 3:49 pm

The Keyhole Nebula is not NGC 3324

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Re: APOD: The Great Nebula in Carina (2017 Jun 13)

Post by Chris Peterson » Tue Jun 13, 2017 3:58 pm

DrC wrote:The Keyhole Nebula is not NGC 3324
I don't think the Keyhole Nebula has any catalog designation at all. It's simply an obscured section of NGC 3372.
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Re: APOD: The Great Nebula in Carina (2017 Jun 13)

Post by neufer » Tue Jun 13, 2017 4:06 pm

DrC wrote:
The Keyhole Nebula is not NGC 3324
https://en.wikipedia.org/wiki/NGC_3324 wrote: <<NGC 3324 is an open cluster in the southern constellation Carina, located northwest of the Carina Nebula (NGC 3372) at a distance of 7,560 ly from Earth. It is closely associated with the emission nebula IC 2599, also known as Gum 31. The two are often confused as a single object, and together have been nicknamed the "Gabriela Mistral Nebula" due to its resemblance to the Chilean poet. NGC 3324 was first catalogued by James Dunlop in 1826.>>
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Re: APOD: The Great Nebula in Carina (2017 Jun 13)

Post by Ann » Tue Jun 13, 2017 4:23 pm

Gabriela Mistral, Nobel Prize-winning poet.
Photo: Anna Riwkin-Brick.


The Gabriela Mistral Nebula is a spitting image of the real deal, isn't it?














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Re: APOD: The Great Nebula in Carina (2017 Jun 13)

Post by Chris Peterson » Tue Jun 13, 2017 5:14 pm

Ann wrote:The Gabriela Mistral Nebula is a spitting image of the real deal, isn't it?
Pretty good. But I'd have gone with the Alfred Hitchcock Nebula.
ah.jpg
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Re: APOD: The Great Nebula in Carina (2017 Jun 13)

Post by tEH sNORK » Tue Jun 13, 2017 5:28 pm

What's with the weird link to the taco dog?

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Re: APOD: The Great Nebula in Carina (2017 Jun 13)

Post by illexsquid » Tue Jun 13, 2017 9:20 pm

tEH sNORK wrote:What's with the weird link to the taco dog?
I wondered if maybe the Imgur image had been changed after it was posted, but this makes a kind of odd sense. The dog is in disguise and has thus "changed his appearance", which is the hyperlinked text.

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Re: APOD: The Great Nebula in Carina (2017 Jun 13)

Post by neufer » Wed Jun 14, 2017 1:49 am

illexsquid wrote:
tEH sNORK wrote:
What's with the weird link to the taco dog?
I wondered if maybe the Imgur image had been changed after it was posted, but this makes a kind of odd sense. The dog is in disguise and has thus "changed his appearance", which is the hyperlinked text.
https://en.wikipedia.org/wiki/Kenneth_Cockrell wrote:
<<Asteroid 14917, Taco, was discovered on January 8, 1994 by the Spacewatch project at Kitt Peak Observatory. Taco has a period of 4 years, 289 days. It was named for Kenneth Dale "Taco" Cockrell (born in 1950), an American astronaut and a veteran of five space shuttle missions.
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