Upper limit on star mass

[luc]

http://www.universetoday.com/am/publish/upper_limit_star_size.html?422005

 

The maximum mass that a star can possess is around 120-200 solar masses

[Martin]

http://www.universetoday.com/am/publish/upper_limit_star_size.html?422005

 

The maximum mass that a star can possess is around 120-200 solar masses

 

I was taught some years ago a theoretical prediction that around 100 would be a limit because the star's own light would drive away surrounding gas and dust.

 

when she gets too big she burns so hot that her own energy drives away material and so she cannot grow any more

 

this was a CALCULATED not an observed upper limit.

 

Now I see they have made statistical observations and established the real upper limit.

 

this is very nice. I am glad to see this notice. thanks

[Martin]

luc, in case you are interested I have found the journal article about this, by these two people Oey and Clarke that your news item mentioned.

 

http://arxiv.org/abs/astro-ph/0501135

Statistical Confirmation of a Stellar Upper Mass Limit

Authors: M. S. Oey (U. Michigan), C. J. Clarke (IoA, Cambridge)

Comments: PDF, 5 pages, 4 figures. Accepted to the Astrophysical Journal Letters

 

"We derive the expectation value for the maximum stellar mass (m_max) in an ensemble of N stars, as a function of the IMF upper-mass cutoff (m_up) and N. We statistically demonstrate that the upper IMF of the local massive star census observed thus far in the Milky Way and Magellanic Clouds clearly exhibits a universal upper mass cutoff around 120 - 200 M_sun for a Salpeter IMF, although the result is more ambiguous for a steeper IMF."

 

now you can compare, if you want, and see if the Journalist who wrote the news item has accurately reported what Oey and Clarke say. But the technical language will make it a little harder to read

[Martin]

I have been told some more about this. their figure of 200 solar may not be the true upper bound for very young stars

 

when a star is just forming and hasnt begun to burn brightly yet it might sometimes collect even more mass, like 250 solar

 

after it begins regular burning and has a "solar wind" streaming out and lots of light, then it will shove the cloud away and it will also lose a lot of material it started with, by blowing it off