What determines a star's mass when it is born?

On Mon, 17 Apr 2000 you wrote:

> When a star is born, what determines what it's mass will be?

The mass of a star depends on many different factors - how much gas is in
the nebula where the star is born, the temperature of the gas, the density
of the gas, and magnetic fields, and any rotation of the cloud. There is
an equation giving a mass called the "Jeans Mass", which is the amount of
mass needed for a star to start forming. But it is doubtful that all of
this mass ends up on the final star.

The effects of magnetic fields and rotation are the largest uncertainties!

So, the mass of a star depends on how much stuff is around, plus a lot of
complex physics that is still poorly understood.

Thanks for writing!

Sincerely,
Kurtis Williams

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