Stars Have a Weight Limit

Mike writes "Using NASA's Hubble Space Telescope, astronomers made the first direct measurement within our Milky Way Galaxy, and concluded stars cannot get any larger than about 150 times the mass of our sun. The astronomers used the Hubble to probe the Arches cluster, the densest in our galaxy. This finding takes astronomers closer to understanding the complex star formation process. It also gives the strongest backing yet to the notion stars have a weight limit."

Comments

Disagree

[Ghetto_D]

I disagree, Stars have no weight limit

http://www.starjones.com/

//I'm awful, I know

Proven false

[Dram]

Clearly Kirstie Alley is proving this false.

Else

[Dolly_Llama]

concluded stars cannot get any larger than about 150 times the mass of our sun.

Else they have to pay for two seats.

Re:Else

[ekuns]

Hmm, last I checked, gravity discriminates against fat people.

Gravity doesn't discriminate against fat people. It pulls on them too. Just imagine if all you had to do to avoid gravity was gain weight. (Wait a minute...)

Just think, won't be able to say this much longer:

[sgant]

"Using NASA's Hubble Space Telescope...

Yeah, in the very near future, they'll say "wow, if only we had an orbiting telescope..."

Back to the stone-ages for us!

hmmm

[crimson_1190]

I think Anna Nichole smith has proved that one wrong. she hasn't lost weight, mearly collapsed in on herself

150 solar mass -- not a hard limit

[helioquake]

I've said this on other forums but...

That 150 solar mass limit is not a hard limit. There will be some statistical probability to find a star greater than 150 solar mass. Figer's finding indicates that he could not find a star any more massive than 130 solar mass (in the Archer cluster? is that the pistol star again?).

This will be an observational constraint for stellar model parameter. Any future stellar evolution theory has to take into account that there are very few number of stars that have a mass greater than 130 solar mass, and none above 150 solar.

[Hey, some stellar evolution scientists would tell you today that there can't be a star any more massive than 80 solar mass! This topic is still debated for its accuracy. So take it with a grain of salt.]

Re:150 solar mass -- not a hard limit

[4of12]

That 150 solar mass limit is not a hard limit.

Bottom of TFA also cautions that.

So, all this prompts me to come up more stupid questions of

• what the lower mass limits are, or, more generally,
• what does the star mass distribution function look like?
• How does that star mass distribution function vary or correlate with star age?
• Has anyone come up with theoretical models for energy production in stars that explains the distribution of observed star masses and observed star energy output?

OK, I'll stop asking questions now.

Re:150 solar mass -- not a hard limit

[helioquake]

You should look up the Nature article. The author himself is more cautious in the main text (c.f., his abstract says a bit firmly). And you will understand why the number 150 solar mass came about.

Re:150 solar mass -- not a hard limit

[wanerious]

Those are excellent questions:

a) Lower limits are roughly 1/20 solar mass. Less mass than this can't product the temperatures and densities needed for hydrogen fusion.

b) roughly the population dies off as M^{-2.5}, with some hard cut-off at high and low mass. There are many more low- than high-mass stars.

c) Age goes roughly as M^{-3.5} or so. High mass stars don't live very long at all.

d) Yes! Not only energy output, but elemental abundance evolution. That was my thesis.

Reading the article...

[jd]

It does NOT say that stars over 150 solar masses can't exist, only that the cluster is missing them. So, if the Anonymous Coward who walked off with them would own up, everything would be ok.

Re:Just think, won't be able to say this much long

[brilinux]

Unfortunately, this is not a troll; this is true. It is a shame that we are going to lose something that has been so valuable to us when NASA decomissions it soon, despite that some say that ground based telescopes are good enough now. Good bye, Hubble.

Article says

[Profane MuthaFucka]

Regarding the cluster that was studied:

"It resides 25,000 light-years away from Earth in our galaxy's hub"

Ahhh, it's an unswitched star topology network.

well

[Joe the Lesser]

Wouldn't any accumulation of mass about that size that's not a star be a black hole?

And the larger the star the shorter it's life span, so if a star gathers too much mass in it's forming stages will it just become a black hole beforehand or lose weight and then begins it's short life span normally?

Re:well

[ekuns]

Wouldn't any accumulation of mass about that size that's not a star be a black hole?

I think the issue is that if you start with a diffuse cloud whose mass is too great, as the inner part of the cloud collapses and starts to heat up and eventually grow, its radiation pressure on the cloud's dust particles will be greater than the force of gravity on those particles. The outer layers of the cloud will be blown into interstellar space. This causes a limit to the maximum mass of a star.

You could probably create a larger star then the limit spoken of in the article by merging two smaller ones. Thus, if the above process limits the maximum star mass to (say) 140 stellar masses, then once you have formed two stars of that mass, just merge them into one star of much larger mass. However, getting two stars to collide in such a way that they merge takes some doing.

By the way, it is believed that there is an upper mass limit for a newly formed black hole, which is obviously smaller than the maximum mass for a star. With stars larger than a certain size, the stellar core collapses more rapidly than the outer layers and the "explosion" from the stellar core's collapse blows the star's outer layers into space instead of allowing them to collapse as well.

Of course, two black holes can merge, assuming the accretion disks and polar jets don't provide enough pressure to prevent the black holes from approaching closely. The frame dragging that takes place around a black hole may (speculation on my part) make it easier for black holes to merge than for stars of the same size to merge.

Re:Just think, won't be able to say this much long

[sgant]

Wow, how did this get modded as a troll? Are there mods out there that wish for the demise of Hubble or something? This is a very real thing that's happening and it's going to be a tragic loss.

I rank the success of Hubble right up there with Apollo in terms of NASA's crowning moments.

Never trust a scientist that tells you something..

[exp(pi*sqrt(163))]

...is impossible.

Never trust a reader to correctly interpret a story posted on /. that is a misunderstood link to a pop science report about a paper published by a scientist. I think the scientists themselves are doing fine without the /. commentary on how they could do their job better.

Hey, there is a primary article at Hubble Site

[ekuns]

A better read than the ./ article reference is an article at hubble site.

Re:Direct measurement?

[ekuns]

What exactly do they consider direct versus indirect?

The article at hubblesite answers your question:

Figer estimated the stars' masses by measuring the ages of the cluster and the brightness of the individual stars. He also collaborated with Francisco Najarro of the Instituto de Estructura de la Materia in Madrid, who produced detailed models to confirm the masses, chemical abundances, and ages of the cluster's stars. [ ... ] Astronomers must know the cluster's distance to reliably estimate the brightness of its stars, a key ingredient used to estimate a star's mass. The cluster also must be close enough to see individual stars.

Re:Just think, won't be able to say this much long

[Zaak]

It will cost just as much to repair the Hubble as it would to put something else more compact and powerful out there, so troll or not, Hubble needs to make way for leaner and more powerful machinery.

I wouldn't mind Hubble dying if there were a replacement for it, but there isn't one. JWST isn't going to be active until 2011, and it is infrared-only.

TTFN

Uh, what???

[Caspian]

You mean to tell me that these monstrosities weigh under 150 Sol masses???

Small correction...

[MattHaffner]

A white dwarf is the remnant from a low to mid-mass star (less than about 10 solar masses). White dwarves do not go supernova unless they have a very close binary companion that begins to dump mass onto its surface.

As a side note, white dwarf+companion supernova have characterstics in their spectra that are different from those of a single massive star collapse. As a result, they are distinguished by the labels Type Ia (for the WD binary SN) and Type II (for most single massive star SN), Ib, and Ic (for oddball stars that have been modified before the SN occurs). The labels are a bit strange because SN were classified by spectra before the explanation for the difference in their spectra existed.

Finally, although I'm not an expert in massive star formation, I think the 120-150 solar mass limit is not from a fast-burning argument, but from an argument that arises from looking at how such a massive system evolves dynamically in the early part of its life. Most massive stars have significant "winds" that slowly shed material from their envelops right from the start. It may be that such a process in stars with a chance to get larger end up disrupting the accretion process too fast.

Re:Just think, won't be able to say this much long

[FleaPlus]

So show your support for the Hubble Origins Probe, which would cost less than a repair and image 20 times as fast.

Re:Just think, won't be able to say this much long

[jnicholson]

It's a cross between Incoherent and Rant. That's my story, and I'm sticking to it.