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

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

[Scrameustache]

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.

I, for one, am eagerly awaiting the slashdot headline that will read "Distant galaxy made up of stars 200 times the size of our sun discovered".

Never trust a scientist that tells you something is impossible, there's another out there waiting for him to die so he can publish the proof to the contrary. Meteors used to be physically impossible, with the math to prove it. The human body used to be said to be unable to survive a speed (yes, speed) of more than 30 kph, etc.

I like my scientists to say "under the current model it would seem unlikely that...", rather than "it is impossible that...". Those are the good scientists (we should make of list of those, cheking it twice, find out who's naughty or nice).

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.

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.

Uh, what???

[Caspian]

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

Re:Uh, what???

[Anonymous Coward]

"These stars are not the most massive known," noted Levesque. "They are only 25 times the mass of the sun, while the most massive stars may have as much material as 150 suns. Nor are they the most luminous, as they are only about 300,000 times the luminosity of the sun, not the factor of 5 million or so attributed to the most luminous stars. They aren't even the coldest stars known - brown dwarfs have such low temperatures that they can't even fuse hydrogen. But the combination of modestly high luminosities and relatively low temperatures DOES mean that they are the biggest stars known, in terms of their stellar diameters."

Link

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.