# Scientists find the most massive star ever!

BGH
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Scientists find the most massive star ever!

## More goodies from the Bad Astromomy blog. Thank you Phil Plait.

This is really cool — astronomers using the Very Large Telescope (yes, I know the name sucks) in Chile and Hubble have discovered the most massive star ever found… and it’s a bruiser, weighing in at 114 times the mass of the Sun. This blows away the previously most massive known star, which had a […]

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This is really cool — astronomers using the Very Large Telescope (yes, I know the name sucks) in Chile and Hubble have discovered the most massive star ever found… and it’s a bruiser, weighing in at 114 times the mass of the Sun. This blows away the previously most massive known star, which had a mere 83 solar masses.

Cripes. That’s a whopping huge star. It’s labeled "A1" in the image above.

They were able to reliably determine its mass because it’s in a binary system, orbiting another star (actually, they orbit each other). The orbital period is — get this — 3.77 days! By carefully observing the Doppler shift of the stars’ spectra, they were able to find out not only the velocities of the stars’ motions in their mutual orbit, but also other orbital parameters (the ellipticity of the orbit, its period, and so on). These in turn can give you the mass.

Usually, the tilt of the orbit messes things up. If you observe it face-on, then you get different numbers than you do if it’s edge on. In other words, without knowing the tilt you can’t really know the mass. However, it was found that this system is an eclipsing binary: every orbit, the stars pass directly in front or behind each other from our view. That’s prefect! You can only get such a system if it is edge-on or nearly so. That constrains the tilt severely, and makes the masses easier to determine.

So in this case, we can be pretty confident of the mass of 114 times the Sun’s. I’ll add that the companion star is no slouch, either: it has 84 solar masses! I don’t know the error bars on these masses, so I can’t say for sure that even the companion star would have broken the old record. It very well might have.

114 solar masses is getting close to the limit on how massive a star can get. More massive stars fuse elements in their core far, far more quickly than lower mass stars. That generates mind-numbing amounts of energy, making the star incredibly luminous. At some point, the star gets so massive and so bright that to a particle sitting on the surface, the force of gravity down toward the star is offset by the force of radiation pressure (literally a pressure exerted by light itself) up, away from the star. The star literally is too bright, and launches its outer surface into space. This is called the Eddington limit, after the astronomer who first figured it out. The actual upper limit is hard to determine, even theoretically. It can depend on many things, such as how fast the star spins, and what elements are in it — oddly enough, the presence of the element manganese lowers the mass limit because it is very effective at absorbing visible light, which tends to make it more susceptible to radiation pressure. That’s the kind of incredibly detailed stuff that makes these calculations very tricky indeed.

In the image above, by the way, the star marked "C" is also a binary and thought to be another biggun, but the masses have not been reliably determined yet.

I keep thinking about this system: a pair of 114 and 84 solar mass stars, so close together they orbit one another in less than 4 days. They must be elongated stars; the centrifugal force would be ferocious, I’d wager, and the upper layers of those stars are barely holding on due to the Eddington limit. Unfortunately, no paper was linked in the press release I received, so I can’t go into too much detail without it being pure speculation. Are the stars blowing off a vast wind of material? Are they emitting gamma rays, like the scary massive binary in the cluster Westerlund 2? How long before these stars explode (and man, when they eventually explode, they’ll explode)? I wish I knew! I’ll have to keep my eyes open for the paper. Stuff like this is thrilling, just to know such an exotic and terrifying beast can exist.

I have to add this… the binary star is at the center of NGC 3603, one of my all time favorite nebulae. Check the banner at the top of this page to confirm this. " /> In fact, I have a whole page about the logo and the nebula. See those weird bluish rings around the bright star above the center of the press release image? The star is Sher 25, another crazy giant in that nebula that’ll blow up one day, and the rings look suspiciously like the rings I studied around a different star for my PhD. I considered observing Sher 25 with Hubble a few years back, until I realized it would take about 20 orbits of data — that’s a lot — and probably a year out of my life to reduce the observations and convert them into usable data. I decided not to go for it. Even now, I wonder if I should’ve tried. It would have been very cool.

Oh well. I love what I’m doing now. I get to write about stuff like this, and that sure is fun too!

JCE
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Wait until Cpt_Pineapple

Wait until Cpt_Pineapple sees this!

Ok:

1. This is outstanding!  That star is HUGE!!!!  I will be very interested to find out when/if that thing explodes.

2. They couldn't come up with a better name than Very Large Telescope?  Whatever, that telescope is my new hero.

3. I wish my thighs and butt had the Eddington limit.

Cpt_pineapple
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I'm going to try to find the

I'm going to try to find the radius of this beast. Just a sec when I get my analytical mechanics text.

BGH
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Cpt_pineapple wrote:

Cpt_pineapple wrote:
I'm going to try to find the radius of this beast. Just a sec when I get my analytical mechanics text.

Let me know when you figure it out.

114 solar masses, that bugger is HUGE!! I love this part of the article:

"I keep thinking about this system: a pair of 114 and 84 solar mass stars, so close together they orbit one another in less than 4 days. They must be elongated stars; the centrifugal force would be ferocious, I’d wager, and the upper layers of those stars are barely holding on due to the Eddington limit."

The tidal forces must be freakin' insane.

Cpt_pineapple
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According to my

According to my calculations, the distance between two stars (semi-major asxis) is 0.28 A.U

Iruka Naminori
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Cpt_pineapple wrote: I'm

Cpt_pineapple wrote:
I'm going to try to find the radius of this beast. Just a sec when I get my analytical mechanics text.

VERY cool.

BGH is making me more interested in astronomy / cosmology.  I really don't know much.  My science education sucked and because I like animals, I've focused on life sciences.

(On a related note, I like learning, period. I'm supposed to take Rook's class tonight, but I think I'm going to have to bail.   I'm too tired from troll-hunting all day.)

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Cpt_pineapple
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Cpt_pineapple

Cpt_pineapple wrote:
According to my calculations, the distance between two stars (semi-major asxis) is 0.28 A.U

I forgot to mention this assumes a circular orbit, and the less circular it is the less accurate it is.

BGH
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Iruka Naminori wrote: BGH

Iruka Naminori wrote:

BGH is making me more interested in astronomy / cosmology.

This makes me very happy, space is sooooo cool. I think more people would like it if they would give it chance.

BGH
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Cpt_pineapple

Cpt_pineapple wrote:

Cpt_pineapple wrote:
According to my calculations, the distance between two stars (semi-major asxis) is 0.28 A.U

I forgot to mention this assumes a circular orbit, and the less circular it is the less accurate it is.

I would think the orbits would be elliptical given the masses of the two objects and the short rotational period. Like I said before, the tidal forces would be insane.

Iruka Naminori
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BGH wrote: Iruka Naminori

BGH wrote:
Iruka Naminori wrote:

BGH is making me more interested in astronomy / cosmology.

This makes me very happy, space is sooooo cool. I think more people would like it if they would give it chance.

I wonder...could we have a cosmology class?  (This after I wimp out on Rook.)

Yes, I am copying you (see avatar).

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Cpt_pineapple
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BGH wrote: I would think

BGH wrote:

I would think the orbits would be elliptical given the masses of the two objects and the short rotational period. Like I said before, the tidal forces would be insane.

Yeah, but I don't know the eccentricity. Still, it is a good estimate.

BGH
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Cpt_pineapple wrote: Yeah,

Cpt_pineapple wrote:

Yeah, but I don't know the eccentricity. Still, it is a good estimate.

Oh, I completely appreciate the calculation too, thanks for doing that. I keep trying to visualize the size of this beast. It is difficult to get a good mental image in my head that makes sense.

BGH
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Iruka Naminori wrote: Yes,

Iruka Naminori wrote:

Yes, I am copying you (see avatar).

I see that, you figured out my secret. LOL

Ophios
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BGH wrote: Iruka Naminori

BGH wrote:
Iruka Naminori wrote:

Yes, I am copying you (see avatar).

I see that, you figured out my secret. LOL

That reminds me, what is up with your avatars?

AImboden wrote:
I'm not going to PM my agreement just because one tucan has pms.

BGH
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Ophios wrote: That reminds

Ophios wrote:

That reminds me, what is up with your avatars?

What do you mean?

Teresa Nichols
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From badastronomy.com because . . .

. . . it's a hoax or what, BGH?

Okay, I see it's not a hoax:

this is truly mind-boggling!

Iruka Naminori
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Ophios wrote:

Ophios wrote:
BGH wrote:
Iruka Naminori wrote:

Yes, I am copying you (see avatar).

I see that, you figured out my secret. LOL

That reminds me, what is up with your avatars?

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darth_josh
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Can we tell if they are

Can we tell if they are transferring matter between them in their orbit to combine into a mega-mass? Is this part of a 'birth' of a black hole sometime down the road?

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Ophios
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Iruka Naminori

Iruka Naminori wrote:
Ophios wrote:

That reminds me, what is up with your avatars?

Thanks

Oh, and darth_josh your avatar is hilarious.

AImboden wrote:
I'm not going to PM my agreement just because one tucan has pms.

darth_josh
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Thanks. I LOVE Prince. The

Thanks. I LOVE Prince. The pic is from 'Black Sweat' right after he says, "You'll be screaming like a white lady when I count to three."

Here's the URL:

I ALSO found this

Formation of a black hole 1 minute:

This one is about the XMM - Newton Space Telescope

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BGH
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darth_josh wrote:

darth_josh wrote:

Can we tell if they are transferring matter between them in their orbit to combine into a mega-mass? Is this part of a 'birth' of a black hole sometime down the road?

I am by no means a astronomers, but from the little knowledge I have gained over the years, I beleive that close orbit and the rather large mass of both of these objects it would indicate that the stars are probably sharing some material. The amount they share is for astronomers to predict but I would imagine it would be a fair amount.

In my fairly uneducated guess I would think a star or a binary system like is almost certain to become a black hole at their death, just due to the masses of these two objects.

Vastet
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That's crazy. There's enough

That's crazy. There's enough matter there to recreate our entire solar system 200 times over. :|

Proud Canadian, Enlightened Atheist, Gaming God.

Yellow_Number_Five
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What's even more impressive

What's even more impressive is that this is just God's left nut. Somewhere, dangling a bit lower, on the other side of the universe is his even more ginormous right nut.

Serious question though, how does the mass of this star compare to the proposed masses of supermassive blackholes at the centers of galaxies? As big as this thing is, this would really put it into perspective for me.

I am against religion because it teaches us to be satisfied with not understanding the world. - Richard Dawkins

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deludedgod
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Yellow_Number_Five

Yellow_Number_Five wrote:

Serious question though, how does the mass of this star compare to the proposed masses of supermassive blackholes at the centers of galaxies? As big as this thing is, this would really put it into perspective for me.

In terms of size, this star is probably much bigger than any black hole, since the Schwartzchild radius for any object is exponentially more dense than the density of an ordinary star. However, in terms of mass....Goddamn, that is a different matter. Black holes can be millions of solar masses. The ones which have a Schwarzchild radius of a nuetron star would dwarf this guy (for instance, in perspective, the Schwarztchild radius of the sun is 2 miles, and the Earth is about one centimeter), and most black holes are bigger (size, not mass) than a neutron star.

"Physical reality” isn’t some arbitrary demarcation. It is defined in terms of what we can systematically investigate, directly or not, by means of our senses. It is preposterous to assert that the process of systematic scientific reasoning arbitrarily excludes “non-physical explanations” because the very notion of “non-physical explanation” is contradictory.

-Me