Thursday May 3, 2012, 3pm
Innovation 223
Kevin Luhman
Department of Astronomy and Astrophysics
Penn State University
The Formation of Brown Dwarfs and Wide Planetary Companions
Brown
dwarfs have been discovered at progressively lower masses in recent
years, reaching well into the mass regime of giant planets. Meanwhile,
high-contrast imaging is beginning to uncover planetary-mass companions
in very large orbits around stars and brown dwarfs. It is difficult for
theories of star and planet formation to explain the existence of both
free-floating brown dwarfs and wide planetary companions. I will review
recent observational and theoretical progress in understanding the
origin of these objects. I will begin by describing the latest
measurements of various properties of brown dwarfs, including their
initial mass function, binarity, circumstellar environment (disks,
accretion, envelopes), and spatial and velocity distributions at birth,
and I will compare these data to the predictions of theories for the
formation of brown dwarfs. I will then describe the observed properties
of wide planetary-mass companions and the resulting constraints on
their formation.