Tuesday 21 Jul 2015: Seminar: (TUE) The Outer Architecture of Planetary Systems
Dr Brendan Bowler - California Institute of Technology
Physics, 4th floor 14:00-15:00
High-contrast adaptive optics imaging and spectroscopy are powerful tools to probe the outer architecture of planetary systems and directly study the atmospheres of extrasolar planets. Over the past few years, direct imaging has uncovered a growing number of planetary-mass companions spanning over two orders of magnitude in separation (10–1000 AU). The origin of these companions is unclear; they might represent the tail end of binary star formation, planets formed in situ, and/or the dynamical ejection of close-in planets as a result of planet-planet scattering events. I will discuss our recent efforts to spectroscopically characterize several new planetary-mass companions and what we have learned from them at the individual and population levels. I will also describe discoveries and new statistical results from the Planets Around Low-Mass Stars (PALMS) high-contrast AO imaging survey carried out primarily at Keck Observatory. With a sample size of over 350 young M dwarfs already observed in our ongoing extended survey, PALMS is the largest direct imaging planet search in this stellar mass regime. Altogether, complementary planet-finding techniques sensitive to a broad range of separations are beginning to map the complete architecture of giant planets around the most common stars in our galaxy.