WD1032+011, an inflated brown dwarf in an old eclipsing binary with a white dwarf
journal contributionposted on 23.06.2020, 16:11 by SL Casewell, C Belardi, SG Parsons, SP Littlefair, IP Braker, JJ Hermes, J Debes, Z Vanderbosch, MR Burleigh, BT Gaensicke, VS Dhillon, TR Marsh, DE Winget, KI Winget
We present the discovery of only the third brown dwarf known to eclipse a non-accreting white dwarf. Gaia parallax information and multi-colour photometry confirm that the white dwarf is cool (9950$\pm$150K) and has a low mass (0.45$\pm$0.05~MSun), and spectra and lightcurves suggest the brown dwarf has a mass of 0.067 $\pm$0.006 MSun (70 MJup) and a spectral type of L5 $\pm$1. The kinematics of the system show that the binary is likely to be a member of the thick disk and therefore at least 5 Gyr old. The high cadence lightcurves show that the brown dwarf is inflated, making it the first brown dwarf in an eclipsing white dwarf-brown dwarf binary to be so.