ALMA MEASUREMENTS OF CIRCUMSTELLAR MATERIAL IN THE GQ LUP SYSTEM

ABSTRACT We present Atacama Large Millimeter/submillimeter Array observations of the GQ Lup system, a young Sun-like star with a substellar-mass companion in a wide-separation orbit. These observations of 870 m continuum and CO J = 3-2 line emission with beam size ∼0 3 (∼45 au) resolve the disk of dust and gas surrounding the primary star, GQ Lup A, and provide deep limits on any circumplanetary disk surrounding the companion, GQ Lup b. The circumprimary dust disk is compact with an FWHM of 59 12 au, while the gas has a larger extent with a characteristic radius of 46.5 1.8 au. By forward-modeling the velocity field of the circumprimary disk based on the CO emission, we constrain the mass of GQ Lup A to be M* = (1.03 0.05) ∗ (d/156 pc) M , where d is a known distance, and determine that we view the disk at an inclination angle of 60 5 0 5 and a position angle of 346° 1°. The 3 upper limit on the 870 m flux density of any circumplanetary disk associated with GQ Lup b of