* Astronomy

Title: Discovery of a low-mass companion around HR3549
Author: Dimitri Mawet, Trevor David, Michael Bottom, Sasha Hinkley, Karl Stapelfeldt, Deborah Padgett, Bertrand Mennesson, Eugene Serabyn, Farisa Morales, Jonas Kuhn

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 (10 sigma 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 \simeq 80 AU and position angle of \simeq 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 M_J, 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.

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