A0V Star HR3549A has a Brown Dwarf Companion

Discovery of a low-mass companion around HR3549

Authors:

Mawet et al

Abstract:

We report the discovery of a low-mass companion to HR3549, an A0V star surrounded by a debris disk with a warm excess detected by WISE at 22 μm (10σ significance). We imaged HR3549 B in the L-band with NAOS-CONICA, the adaptive optics infrared camera of the Very Large Telescope, in January 2013 and confirmed its common proper motion in January 2015. The companion is at a projected separation of ≃80 AU and position angle of ≃157∘, so it is orbiting well beyond the warm disk inner edge of r>10 AU. Our age estimate for this system corresponds to a companion mass in the range 15-80 MJ, spanning the brown dwarf regime, and so HR3549 B is another recent addition to the growing list of brown dwarf desert objects with extreme mass ratios. The simultaneous presence of a warm disk and a brown dwarf around HR3549 provides interesting empirical constraints on models of the formation of substellar companions.