# How massive can a star be at birth? [duplicate]

We have discovered some incredibly massive stars. R136a1, the most massive known star is estimated to have 265 times mass as our Sun. Yet it has been burning for at least a million years, and must have shed a considerable mass as stellar wind. In its infancy, R136a1 must have been much more massive.

Which got me thinking about the question: What is the theoretical limit of mass that a newborn star can have?

• @Aaron: The question you linked seems to be rather vague. What do you mean by "size" when it comes to a star? Mass? Radius? :) – sampathsris Sep 15 '14 at 22:46
• @Krumia The accepted answer for that question interprets the question as mass. – HDE 226868 Sep 15 '14 at 23:52
• @HDE226868: And according to that answer, maximum limit is 2 $M_{Sun}$? :D (Not saying this is not a dupe, but that question should have another answer). – sampathsris Sep 16 '14 at 2:43
• "The article Stars Have a Size Limit by Michael Schirber, it's about 150 Solar Masses. However, there's the Pistol Star, which is speculated to be 200 SM." – Aaron Sep 16 '14 at 6:11

I found a text that suggests a Population III star can have a mass between 200 and 10^5$M_{Sun}$. There you can read:
"...This would apply for VMOs larger than $M_c$ $\approx$ 200 $M_{Sun}$. Stars larger than 150$M_{Sun}$ are termed supermassive objects (SMOs)...".
It seems supermassive stars like R136a1 (with masses in excess 150$M_{Sun}$, the accepted upper limit for a non-pop III star) can be formed by the collision of massive stars.
So, It is not difficult to imagine, say, two 150$M_{Sun}$ monsters colliding and forming a 300$M_{Sun}$ object.
• So "Stars larger than $10^5M_{Sun}$ are termed supermassive objects (SMOs), and would collapse directly to black holes due to relativistic instabilities even before nuclear burning, at least if they were metal-free.". You should add that to the answer, I suppose :) – sampathsris Sep 15 '14 at 23:03
• One more thing to add from the text It must be stressed that the existence of VMOs and SMOs is entirely speculative and they are invoked primarily for the purpose of making dark matter. So it seems that 300 times the mass of the sun is the present limit. – LDC3 Sep 16 '14 at 2:04