(Proposal ID) S15B-003

(PI) Hashimoto, Jun

(Proposal Title)
Direct Imaging of Young Planets in Transitional Disk Systems II

(Abstract)
We propose angular differential imaging (ADI) of 7 transitional disks with 
IRCS/AO188 in the L' band to search for young planets in the inside/outside 
cavity of the disks. Carefully selected 7 targets show a large cavity, an 
asymmetric structure, and dust filtration that are potentially created by 
planetary-mass companion(s) due to disk-planet interaction. Furthermore, 
if planetary mass objects exist around our targets, they would be relatively 
bright due to their young ages of less than 10~Myr; hence, proposed 
observations would detect planets with a few to 20~M_Jup in the inside/outside 
cavity. Thus, these young targets would be ideal test-beds to explore the 
planets in the systems. Our main scientific goals are to discover any 
planetary mass companions and their circumplanetary materials in the cavity. 
Because (a) the contrast ratio between the central star and planet tends to be 
smaller in the L' band and (b) an accreting young planet is brighter than 
non-accreting planet, L' direct imaging would be a suitable method to catch 
young planets. By comparing a planetary mass and orbital radius of our 
detected planets with those of previously detected planets, we discuss whether 
they formed through a similar mechanism.