Question about the formation of a massive star

ldc3

I have no problem with description of a small star's formation by gas and dust accretion.
The problem I have is with a massive star. When enough material has accumulated to start the fusion of the star, a stellar wind will start and will clear away the gas and dust nearby. A heavier star would produce a stronger stellar wind. Even with a high density nebula, I would think that there wouldn't be enough material accumulated before the fusion started pushing away the gas and dust.
So, how does a star of 1,000,000 solar masses form?

Steely Dan

There are no stars of [itex]10^6[/itex] solar masses, and there probably never were. The maximum size star that's possible is probably in the several hundred solar mass range.

Chronos

Something around 200 solar masses is believed to be about as big as any star can get and is affected by metallicity of its progenitor material, meaning stars in the very early universe tended to be more massive because the progenitor material was metal poor.

zhermes

That's basically the limiting factor to the maximum mass of stars. Its called the Eddington Limit.

Also see http://en.wikipedia.org/wiki/Eddington_luminosity

ldc3

OK so I overestimated the size of a massive star. It's just that when you see Betelgeuse pictured beside our sun (and it looks about 1000000 times larger, one assumes it has 1000000 times the mass as well.

"A radius of 5.5 AU is roughly 1,180 times the radius of the Sun—a sphere so huge that it could contain over 2 quadrillion Earths (2.15 × 10^15) or more than 1.6 billion (1.65 × 10^9) suns."
http://en.wikipedia.org/wiki/Betelgeuse

phyzguy

Note that the same article says that Betegeuse has about 20x the mass of the sun.

manojr

Idc3, now you got it right. The same Wikipedia article says "In volume, Betelgeuse exceeds the Sun by a factor of about 1.6 billion. Yet the actual mass of the star is believed to be no more than 18 to 19 Suns".