Multiplicity in Stellar and Planetary Astrophysics
Kaitlin Kratter
Harvard-Smithsonian Center for Astrophysics

Binary and multiple stellar systems are common outcomes of the star formation process. More importantly, multiple systems contribute disproportionately to our understanding of topics ranging from stellar structure to cosmology. In this talk I will describe several theories for binary and multiple star formation, focusing on the role of protostellar accretion disks. I show that two modes of binary formation can account for the dependence of the observed binary fraction on stellar mass. Next, I will examine the long term stability of hierarchical stellar and planetary systems. I describe how mass loss due to stellar evolution can trigger orbital instabilities in such systems. These instabilities can produce odd-ball evolved binaries, frequent stellar collisions, and planets on eccentric orbits around evolved stars.

Date:	Jeudi, 8 décembre 2011
Time:	11:30
Where:	Université de Montréal
	Pavillon Roger-Gaudry, local D-460
Contact:	René Doyon