Largest Yellow Star Ever Spotted, One Million Times Brighter than Sun

Largest Yellow Star Ever Spotted, One Million Times Brighter than Sun

An international team of astronomers has spotted the largest yellow star ever discovered, ranking among the ten largest stars found so far.

"Surprisingly large" was the term Olivier Chesneau and his international team used to describe HR 5171 A, a hypergiant star more than 1300 times the diameter of the Sun. Using the European Southern Observatory's Very Large Telescope Interferometer, the astronomers determined that the yellow star is about a million times brighter than the Sun and 50% larger than the famous red supergiant, Betelguese.

This makes HR 5171 A the largest yellow star ever found, and one of the ten largest stars. But that's not all the team discovered -- they also found that HR 5171 A is not alone in the universe. Forming a binary system, it has a low-mass companion star in such close proximity that it is embedded within its dense wind.

"The new observations also showed that this star has a very close binary partner, which was a real surprise," says Chesneau. "The two stars are so close that they touch and the whole system resembles a gigantic peanut."

Only a dozen or so yellow hypergiants have been observed within our galaxy, making them a rarity. On the stellar evolution path to becoming red giants, yellow hypergiants are among the biggest and brightest stars known, and are at a stage in their lives when they are unstable and changing rapidly.

HR 5171 A can be seen by the naked eye, if your eyesight is good enough.

Source: ESO

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Does it have any planets?

They should call it the Peanut System.

Rex Dark:
Does it have any planets?

They should call it the Peanut System.

Elephanthulu ate all of the peanut planets already, the naming of the system is already too late.
The star goes dark next
Oh the unspeakable horror of the old god with a thousand trunks.

IT'S LIKE AN INTERGALACTIC DUMBO.

... That only explains why the hallucinogenic sequence was in that movie.

Oh god the SIGNS WERE THERE THE WHOLE TIME.

OT:
That's super neat! I didn't know stars could co-exist in such proximity. You'd think they would need their space.
I kind of wish that you could observe changes occur in this binary system, but knowing even a bit of astronomy probably points to it never happening in my lifetime.

Captcha: well done

WELL MET

Sounds extremely unstable. The companion will probably fall in.

I don't know how reliable the information is but, has anybody ever seen vsauce? I think it's really interesting, one of the episodes is about the brightest thing.

It explains how brightness is measured and will probably put this one into perspective.

Pyrian:
Sounds extremely unstable. The companion will probably fall in.

The bigger star is losing mass, if was going to fall in it would done it by now.

Ferisar:

Elephanthulu

Anyway, I'm actually on the lookout for a trinary star system with one planet stuck in the middle that rotates in place because the equal pulls of the three suns actually prevent it from orbiting any one of them. You spot one of those anywhere, you lemme know. (And very important: Tell me if the suns are red or yellow.)

FalloutJack:
Anyway, I'm actually on the lookout for a trinary star system with one planet stuck in the middle that rotates in place because the equal pulls of the three suns actually prevent it from orbiting any one of them. You spot one of those anywhere, you lemme know. (And very important: Tell me if the suns are red or yellow.)

I will look every night (because that's when suns are darkest), but reason tells me the planet would have to be super dense to avoid being shredded by the gravitational forces exerted upon it by three suns.

"The two stars are so close that they touch and the whole system resembles a gigantic peanut."

Gigantic, eh? That's a teensy weensy bit of an understatement :D

"HR 5171 A can be seen by the naked eye, if your eyesight is good enough."

Yes, and you guys in the US can hear me farting from across the Atlantic Ocean too, if your hearing is good enough.
Great line though, made me LOL so thanks! ;)

008Zulu:

FalloutJack:
Anyway, I'm actually on the lookout for a trinary star system with one planet stuck in the middle that rotates in place because the equal pulls of the three suns actually prevent it from orbiting any one of them. You spot one of those anywhere, you lemme know. (And very important: Tell me if the suns are red or yellow.)

I will look every night (because that's when suns are darkest), but reason tells me the planet would have to be super dense to avoid being shredded by the gravitational forces exerted upon it by three suns.

Or perhaps too distant to exude that amount of force, the idea being that the combined heat and force would be so equally distributed that the planet would exist in a permanent daylight that would be fierce, but not overpowering.

Still, the red one would be super-dense, for us to beware of.

I don't know if you meant to imply that our sun is yellow, but contrary to popular belief it is in fact white. The earth's atmosphere makes it appear yellow. Evidence for this is seen any time there is a rainbow since it is a prismatic effect causing the white light given off by the sun to be split into the component colors, yellow being one of them.

FalloutJack:

Ferisar:

Elephanthulu

pls no

I don't want to die to to a cosmological terror whose only fear is extraterrestrial mice (on bikes from mars).

albino boo:

Pyrian:
Sounds extremely unstable. The companion will probably fall in.

The bigger star is losing mass...

Stars are constantly shedding mass, especially the big ones. The smaller star picking up that mass will slow its orbit, dragging it in.

albino boo:
...if was going to fall in it would done it by now.

This makes absolutely zero sense. You simply can't say "by now" regarding a recently discovered object. It's probably been spiraling down for a very long time.

Pyrian:

albino boo:

Pyrian:
Sounds extremely unstable. The companion will probably fall in.

The bigger star is losing mass...

Stars are constantly shedding mass, especially the big ones. The smaller star picking up that mass will slow its orbit, dragging it in.

albino boo:
...if was going to fall in it would done it by now.

This makes absolutely zero sense. You simply can't say "by now" regarding a recently discovered object. It's probably been spiraling down for a very long time.

The yellow hypergiant is losing mass in all directions not just towards the smaller star. The age of stars in unaffected by when it was discovered. The mass the yellow hypergiant was higher in the past than it is today as the time goes on the chances of the small star falling grows less. Yellow hypergiants are formed by stars of 20-50 solar masses expanding and losing up to half their mass. During the 1000 or so years that the star will stay as a yellow hypergiant its will lose about 1% of the mass of the sun per year.

 

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