(Proposal ID) S16A-156

(PI) Uyama, Taichi

(Proposal Title)
Search for Exoplanet Accretion Signatures in TW Hya Transitional Disk

(Abstract)
We propose integral field spectroscopy of TW Hya with Keck/OSIRIS combined with
 Adaptive Optics to search for any actively mass-accreting planets. The Pabeta 
line emission in the Jn2 band (1.228-1.289 mum) is used for the accretion 
signature. The SEEDS project reported a dozen of protoplanetary disks having 
small inner gap (transitional disks) around Young Stellar Objects (YSOs). 
This structure is thought to be a signature of exoplanet but detection reports 
of planets within the gaps are still controversial. This is because most of 
the YSOs are too far (typically 140pc from the Sun) to detect any possible 
exoplanets in the gaps. TW Hya is the only YSO in the vicinity (54pc) and the 
multiple gaps in its disk have been recently reported at 20 and 80 AU. This 
object is the most suitable target for exoplanet search in the disk gaps. By 
measuring the mass accretion onto a companion, we can detect very small 
exoplanets as 0.2 MJ. If we successfully detect any exoplanets with active 
mass accretion, we can demonstrate the relationship between the planet 
formation and the transitional disk. Even if null-detection, we can set 
a better constraint of the mass of potential planet(s).