Empirical Constraints on Planet Formation Theories, M. Meyer
Thursday, February 16, 2017
Physics & Astronomy Building (PAB)
Department of Physics and Astronomy
PHYSICS & ASTRONOMY COLLOQUIUM
Dr. Michael R. Meyer
Department of Astronomy
University of Michigan
“Empirical Constraints on Theories of Planet Formation: Capitalizing on Diversity”
Planetary bodies provide suitable environments for the emergence of life. Thus knowing their distribution as a function of mass, orbital radius, and bulk composition can help constrain the possible number of habitable worlds. Observations in the accessible regions of our Galaxy provide empirical constraints on planet populations. Yet extrapolation of these results to the rest of the observable Universe requires understanding the dependence of formation and evolution on a wide range of initial conditions. On the one hand, this process is simple: small bodies grow into larger ones through collisions (and sticking) of solid particles, or through local gravitational instabilities. On the other hand, the specific outcomes depend on a large number of complex properties requiring coupled understanding of dynamics, chemistry, and radiative transfer over several orders of magnitude in solid particle size, gas density and orbital radius. I will first introduce some basic concepts of planet formation, with a focus on how they might depend on stellar mass. Then I will review current observational results (RV, micro-lensing, and direct imaging) that constrain these theories and outline a framework to quantify our ignorance. Finally, I will propose experiments (some underway with new IR instrumentation on 8-meter class telescopes, and others planned for future facilities) that aim to efficiently improve our understanding. One exciting prospect is to determine peak in the surface density distribution of gas giants (and the minimum of the companion mass ratio distribution) as a function of stellar mass suggesting current theories to a very stringent test.
STUDENTS – after the talk, you’re encouraged to return to the 2nd floor Atrium lounge to meet with the speaker.
COFFEE – coffee and cookies will be available in the 2nd floor Atrium lounge at 1:15 p.m.
CELL PHONES – as a courtesy to the speaker and audience, please set your cellphones to “silent” mode. Thanks!
Jodi Guthrie - Assistant to the Chairjodi@uwo.ca
519-661-2111 ext. 86438