Young and directly-imaged exoplanets offer critical tests of planet-formation models that can’t be matched by RV and transit surveys of mature stars. However, these targets have been extremely elusive to date, with no exoplanets younger than ~10-20 Myr and only a handful of directly-imaged planets at all ages.
I am leading a team that exploits a new observing technique (nonredundant aperture mask interferometry) to achieve high-contrast observations at the diffraction limit of large telescopes, extending direct-imaging planet searches outward to the nearest star-forming regions. We recently reported the discovery of LkCa15 b, which is located inside of the known gap in LkCa15’s protoplanetary disk and is surrounded by spatially resolved clouds of gas and dust; these features imply that LkCa15 b has been caught at formation. I will describe our newest observations of the LkCa15 system, the status of our survey program, and the prospects for future searches.
I also have been studying the growing population of planetary-mass companions (M=5-20 MJup) in very wide orbits (a=100-1000 AU) around young stars, which pose a significant challenge to models of both binary and planet formation. I have calculated the first measurements of their frequency and mass function, and I am pursuing several followup programs to ascertain their detailed properties and search for circum(planetary?) disks. In light of these new results, I will discuss our ability to explain these systems as either “planets” or “binaries”.
Adam Kraus (U. Hawaii)
February 09, 2012
14:00 - 15:00