Speaker
Description
Perhaps the greatest mysteries of gas giant and brown dwarf formation reside at the youngest (few Myr) ages, when such objects are being born in their natal circumstellar disks and the corresponding theoretical models predict an enormous range of luminosities. In practice, this means that any observations of such objects help open a window into the earliest stages, and increasing the current census of the youngest imaged exoplanets would be a significant step forward. We report on a two-phase program aimed at such new discovery space in the nearby Taurus and Ophiuchus star-forming regions. Phase 1 used Keck’s infrared pyramid wavefront sensor (PyWFS) to obtained diffraction-limited imaging of ~200 young stars that had previously never been imaged at high angular resolution, in part due to their optical faintness making them unsuitable for typical AO systems using optical wavefront sensing. Follow-up work has already confirmed 4 new planetary-mass companions, including the lowest-mass planets imaged to date in these 2 regions, with more candidates currently being vetted. Phase 2 is beginning in 2026 as the Keck All-Sky Precision AO (KAPA) system completes its commissioning and begins science operations. KAPA’s multiple laser guide stars (LGS) and near-IR tip-tilt sensing will substantially improve upon the AO-delivered images of current single-LGS systems, and open the door to studying the youngest (most dust-enshrouded) and lowest-mass members of these regions. Together, this 2-stage program will work to confirm and characterize very young companions, build an empirical color–magnitude sequence at Myr ages to confront hot/warm/cold-start predictions, and measure the demographics of the youngest giant planets and substellar companions.
