Oral Presentation

Imaging the Youngest Exoplanets

Author(s): Michael Ireland (ANU) et al.

Presenter: Michael Ireland (Australian National University)

Direct images of the youngest giant exoplanets offers a window into the most complex and elusive processes of planet formation. Empirical evidence is mounting that giant planets with separations from their host star wider than that of Jupiter, and detectable by techniques such as angular differential imaging are relatively rare. At a 5 AU separation (0.035 arcsec), a young Jupiter is barely resolved from its host star on 8-10m class telescopes, and is amenable to aperture mask interferometry and kernel phase techniques. I will describe observations from Keck, VLT and Subaru of a number of young stars observed in our exoplanet search in the Taurus and Ophiucus star forming regions. This will include the enigmatic LkCa 15 system, where reported evidence for a planet is becoming more difficult to interpret, as most of the emission is morphologically consistent with a combination of separation of dust grain species by radiation pressure, forward scattering and possibly quantum heating. I will also describe our recently submitted work on Oph IRS 48 and HD 169142, where we again find show evidence of significant evolution in grain size distribution by radiation pressure, and where gas densities must be significantly higher than inferred from CO observations. Finally, I will describe how future observations from Subaru and collaborations between observatories can solve many of the remaining mysteries in distinguishing planet signatures from disk signatures.