Space Forum / Astronomy / September 2006

The first gaseous clouds, which congealed from the primordial soup of
sub-atomic pieces parts, consisted of the three lightest elements of the
periodic table: Hydrogen (±75%) Helium (±24%) and Lithium (a smattering).
Because there were no "heavy elements" (a moniker assigned to all other
elements), the initial star forming gas cloud had to accumulate appr. 15
times the mass of our sun in order to exert enough internal pressure to
start nuclear fusion. Because there were no "impurities" the early
supergiant stars burned bright, fast and furious, some of them for only 250
million years (a mere blink of the eye, in cosmological terms) at which time
they all went supernova to seed the cosmos with the first generation of all
the elements we've come to know and love. Because of their initially huge
mass, their cinders collapsed right past the White Dwarf and the Neutron
Star stage to their final destination, namely a Black Hole. The black holes,
because of their immense gravitational influence and spinning at high speed,
began dragging the neighborhood stars along in this spiral dance, gobbling
up some that ventured too close, speeding up others to the point where their
escape velocity kept them at a safe distance.  The first galaxies were born.

The formation of Supergiant stars has ceased, since almost all intergalactic
gas now contains heavier metals, compliments of the initial cornucopia of
supernovae, and therefore new stars only requires an accumulation of .8 to
2.0 solar masses for fusion to be initiated. Because the new stars are
smaller and contain appr 4% impurities, their lifespan is greatly extended
from the original stellar lifespan, measured in millions of years,  to 10 -
15 billion years.

"How the Really Big Stars Form
September 27th, 2006

Astronomers think they've got a handle on how Sun-sized stars come
together. But the formation of the largest stars - more than 10 times
the mass of the Sun - still puzzle astronomers. New observations on a
20 solar mass star have revealed that these giant stars maintain a
torus of material around themselves. They can continuously feed from
this "doughnut" of material, while powerful jets of radiation pour
from their poles. The material can continue gathering onto the star
while avoiding this radiation, which would normally blast it back into
space."

http://www.universetoday.com/2006/09/27/how-the-really-big-stars-form/

Double-A