Abstract

The direct-imaging detections of accreting young planets open up a new era of planet formation studies. These observations allow us to witness how planets assemble, constrain planets' mass accretion processes, and understand the interactions between planets and their natal environment. Hubble Space Telescope (HST) naturally obtains high-Strehl-ratio images over a broad wavelength range, particularly the optical and ultra-violet (UV) bands where planetary spectra show accretion signatures. This capability offers exciting opportunities to discover and characterize accreting planets. Recently, we embarked on the Hubble Accreting Luminous Protoplanets in H-Alpha (HALPHA) Survey to search for accreting planets in gaps of transition disks. I will present the survey's motivation, design, and early results. I will also describe the follow-up effort in validating the nature of the program's first discovery, the protoplanet candidate AB Aur b. The exquisite high-contrast images collected by our survey create numerous collaboration opportunities for investigating the formation and evolution of giant planets together.