The 2012 John Bahcall Lecture in Astrophysics
"The Formation of Massive Stars"
Prof. Christopher F. McKee
Departments of Astronomy and of Physics, University of
California, Berkeley
John Bahcall was one of the greatest astrophysicists of the last 50
years. His impact extended well beyond his research, through his
mentoring of generations of astrophysicists and his influence on
science policy. His work touched many fields, including the study of
supernovae, most of which result from the explosion of stars with a
mass more than about 10 times the mass of the Sun. Such stars are
responsible for creating most of the heavy elements in the universe,
for governing the evolution of galaxies, and quite possibly for
re-ionizing the universe a few hundred million years after the Big
Bang. The formation of these stars can be understood as an extension
of the theory of low-mass star formation, generalized to include the
effects of interstellar turbulence. However, a major problem must be
overcome: For massive stars, the outward force due to radiation
pressure exceeds the inward force due to gravity; how can gas accrete
onto the protostar in that case? Circumstellar disks, outflow
cavities, and radiative Rayleigh-Taylor instabilities all contribute
to the solution of this problem. These conclusions are validated by
means of 3D radiation-hydrodynamic simulations of high-mass star
formation. Massive stars are powerful sources of ionizing radiation,
which has a significant impact on star formation.
Host:
Prof. Amiel Sternberg, x7590
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