APOD: Antares and Clouds (2012 Apr 17)

[APOD Robot]

Antares and Clouds

Explanation: Antares is a huge star. In a class called red supergiant, Antares is about 850 times the diameter of our own Sun, 15 times more massive, and 10,000 times brighter. Antares is the brightest star in the constellation of Scorpius and one of the brighter stars in all the night sky. Located about 550 light years away, Antares is seen on the left surrounded by a yellowish nebula of gas which it has itself expelled. Radiation from Antares' blue stellar companion helps cause the nebular gas to glow. Far behind Antares, to the lower right in the above image is the globular star cloud M4, while the bright star on the right is Al Niyat.

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[Quantic]

And what is the name of the other globular cluster in the picture?

[Case]

And what is the name of the other globular cluster in the picture?

NGC 6144.

[zingsy]

There is a mistake in the APOD description. The cluster described as being 'far behind Antares'
is actually NGC 6144 while the bright cluster to the lower right of the pic is the cluster M4.

[Ann]

I'm going to paste my comment from a Recent Submissions thread here:

Ivan Eder, you've done full justice to this colorful region of the sky. You really bring out how the emission and reflection nebulosity is unevenly distributed around Sigma Orionis. (It's a double star, and I think that only one of the components is hot enough to produce a lot of Ha emission.) But please not how the nebulosity around both Sigma Orionis and Antares seems "thicker" on the right side of the star, as if some strong "wind" had blown the gas and dust to one side of the stars.

Let me add that this is a glorious image of a fantastically colorful region of the sky. We see the trademark blue reflection nebulosity here, but the Antares region is also one of the few regions of the sky where we can see yellow reflection nebulosity, as the light from the red supergiant Antares is reflected in dust clouds. What a coincidence that photogenic globular cluster M4, a background object, is seen among the sparkling colors of the Antares region.

Ann

[Boomer12k]

Must be some hellacious Solar Winds....

:---[===] *

[Beyond]

NGC 6144

Is there an astronomical designation NCC 1701 ? I Googled, but didn't find anything except StarTrek. But then, i don't really know what to Google for.

[RJN]

There is a mistake in the APOD description. The cluster described as being 'far behind Antares'
is actually NGC 6144 while the bright cluster to the lower right of the pic is the cluster M4.

The description was indeed unclear. Which globular cluster is M4 is now better described. I apologize for the oversight.

- RJN

[Keina]

"Antares is about 850 times the diameter of our own Sun"
Suns diameter is approx.1 392 000 km. Is Antareses diameter then 850x1 392 000km= 1 183 200 000 km? Or is Antareses volume 850xSuns volume? Sounds more plausible to me.

[Chris Peterson]

"Antares is about 850 times the diameter of our own Sun"
Suns diameter is approx.1 392 000 km. Is Antareses diameter then 850x1 392 000km= 1 183 200 000 km? Or is Antareses volume 850xSuns volume? Sounds more plausible to me.

Antares's diameter is more than 850 times that of the Sun. It isn't called a supergiant for nothing!

[idahogie]

If the diameter of Antares is 850 times that of the sun, then its volume would be a factor of 850^3 greater, right? Yet it is only 15 times more massive than the sun?

That would make its average density something like 15/850^3 that of our sun.

[Chris Peterson]

If the diameter of Antares is 850 times that of the sun, then its volume would be a factor of 850^3 greater, right? Yet it is only 15 times more massive than the sun?

That would make its average density something like 15/850^3 that of our sun.

Supergiant stars are very tenuous. Planets could be orbiting inside of them. (They are still very dense at their cores, but have huge, tenuous outer layers.)

[idahogie]

Supergiant stars are very tenuous. Planets could be orbiting inside of them. (They are still very dense at their cores, but have huge, tenuous outer layers.)

Thanks, Chris. That's amazing.

It makes me think that a supergiant must not really have a surface -- at least not the way that we think of our sun's surface because of all the cool pictures -- where it looks like a lake of plasma swirling with magnetic currents, and periodically shooting streamers that splash back down. The surface of a supergiant must just fade out like a planetary atmosphere. Is that the case?

[Pastorian]

Supergiant stars are very tenuous. Planets could be orbiting inside of them. (They are still very dense at their cores, but have huge, tenuous outer layers.)

I expect that this would explain the nebula around the star as described by today's image caption:

Antares is seen on the left surrounded by a yellowish nebula of gas which it has itself expelled.

[Ann]

NGC 6144

Is there an astronomical designation NCC 1701 ? I Googled, but didn't find anything except StarTrek. But then, i don't really know what to Google for.

Source: http://aladin.u-strasbg.fr/simbad-
thumbnails/thumbnails724.html

Here it is. It's a spiral galaxy. My software, which isn't very reliable in these matters, says that it is a spiral galaxy of type Sb (similar to the Andromeda Galaxy), 240 million light-years away, and that it is quite large and luminous, twice as bright as the Milky Way.




Ann

[Beyond]

uh, wait a minute Ann, it says NGC, not NCC. Nice bright galaxy, but one letter off.

[Psnarf]

I duckduckwent [my new favorite search engine: https://duckduckgo.com] and found this at the top of the list.

The skies are green and glowing
Where my heart is
Where my heart is
Where... the scented lunar flower is blooming
Somewhere, beyond the stars
Beyond Antares

I'll be back though it takes forever
Forever is just a day.
Forever is just another journey
Tomorrow a stop along the way

And let the years go fading
Where my heart is
Where my heart is
Where my love eternally is waiting
Somewhere, beyond the stars
Beyond Antares
http://images.wikia.com/memoryalpha/en/ ... ntares.ogg

-http://en.memory-alpha.org/wiki/Beyond_Antares

[Ann]

uh, wait a minute Ann, it says NGC, not NCC. Nice bright galaxy, but one letter off.

Ooops, you're right, Beyond!

NCC, eh? It doesn't sound too astronomical to me. NGC means New General Catalogue, and while it isn't very new these days, it was new by the time it arrived in the late 19th or the early 20th century. But NCC? New Cosmic Catalogue?

There is a Swedish building and construction company called NCC, and they built Malmö's famous skyscraper, Turning Torso.

But what about NCC 1701? Would it be the 1701th building constructed by NCC? I doubt it.

Ann

[Beyond]

Ok, thanks Ann. I didn't realize that -NGC- was a catalog designation. My ignorance of cosmological things is just about limitless. But hey, you found a Nice blue galaxy to look at, right

[Keina]

"Antares is about 850 times the diameter of our own Sun"
Suns diameter is approx.1 392 000 km. Is Antareses diameter then 850x1 392 000km= 1 183 200 000 km? Or is Antareses volume 850xSuns volume? Sounds more plausible to me.

Antares's diameter is more than 850 times that of the Sun. It isn't called a supergiant for nothing!

Thanks for the info Chris. I read more info from wiki and was astonished that the thing is bigger than orbit of Mars.

[Anthony Barreiro]

This is a beautiful picture full of astronomical wonders -- a yellow supergiant star, a hot blue star, yellow and blue reflection nebulae, red emission nebula, a couple of globular clusters. Wow.

And, I hate to admit that I know this, NCC 1701 is the Starfleet number for the starship Enterprise. You know, with Kirk, Spock, etc. My childhood enthusiasm for Star Trek has had a lasting effect on my mind. I can't remember Kepler's laws of planetary motion, but I could still run the transporter controls in an emergency.

[pleas]

Could Antares convert to a supernova and destroy the Earth?

Phil

[Chris Peterson]

Could Antares convert to a supernova and destroy the Earth?

Antares will certainly end in a supernova, sometime in the next million years or so (and possibly in a few minutes). But it's much too far away to pose any danger to Earth (by at least a factor of 20). It will, however, be spectacular, lighting up the night sky and even being visible in the daytime.

[Case]

uh, wait a minute Ann, it says NGC, not NCC. Nice bright galaxy, but one letter off.

NCC, eh? It doesn't sound too astronomical to me.

Ok, thanks Ann. I didn't realize that -NGC- was a catalog designation.

The letters ‘NCC’ in the designation ‘NCC 1701’ were never explained in the canon Star Trek universe, but the novel ‘Star Trek: Best Destiny’ mentions that it stands for “Naval Construction Contract”.

[Chris Peterson]

The letters ‘NCC’ in the designation ‘NCC 1701’ were never explained in the canon Star Trek universe, but the novel ‘Star Trek: Best Destiny’ mentions that it stands for “Naval Construction Contract”.

Perhaps, but the actual reason for using NCC is well known: it is a combination of the NC prefix used for U.S. aircraft registrations (the "C" is no longer used), and a Soviet-era CC prefix. By combining the two into NCC, the Star Trek creators were emphasizing a future of peace and cooperation.