Colloquium on Jul. 16th, 2019

Circumbinary Accretion: From Supermassive Binary Black Holes to Circumbinary Planets

Speaker: Dong Lai (Cornell University)

Venue: Room 2317, SWIFAR Building

Time: 3:00 PM, Tuesday, 16th July, 2019

Abstract: 

Circumbinary disks have been observed in a number of young stellar systems, and are the birth place for circumbinary planets found by the Kepler misssion. They are also expected to exist around supermassive black hole binaries as a consequence of accretion from the interstellar medium following galaxy mergers. I will discuss recent works on numerical modeling of circumbinary accretion, focusing short-term and long-term variabilities, and angular momentum transfer between the disk and the binary -- the result suggests that the long-standing notion of binary orbital decay driven by circumbinary disk may be problematic. Implications for planet formation/migration around stellar binaries will be noted. I will also discuss the dynamics and evolution of inclined/warped disks in binaries and connect with recent observations of protoplanetary disks and circumbinary planets.