The Formation of Massive Stars

Massive stars, those larger than 20 times the mass of the Sun, are
very rare, but their extreme luminosities make them both the only type
of young star we can observe in distant galaxies and the dominant
energy sources in the universe today. How such stars form, however, is
a longstanding mystery. Efficient radiative cooling in the dense
clouds where massive stars form should favor fragmentation into
objects of solar mass or smaller. Even if a collapsing cloud exceeds
this mass, massive stars produce so much light that the radiation
pressure they exert on the gas and dust around them is stronger than
their gravitational attraction, a condition that has long been
expected to prevent them from growing by accretion. I discuss recent
simulations that suggest that we have finally solved these two
problems, work made possible by the development of numerical
algorithms for 3D adaptive mesh radiation-hydrodynamics on parallel
supercomputers. I also propose direct observational tests of these
results.