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.