We present the discovery of NGTS-19b, a high mass transiting brown dwarf discovered by the Next Generation Transit Survey (NGTS). We investigate the system using follow up photometry from the South African Astronomical Observatory, as well as sector 11 TESS data, in combination with radial velocity measurements from the CORALIE spectrograph to precisely characterise the system. We find that NGTS-19b is a brown dwarf companion to a K-star, with a mass of 69.5−5.4+5.7 MJup and radius of 1.034−0.053+0.055 RJup. The system has a reasonably long period of 17.84 days, and a high degree of eccentricity of 0.3767−0.0061+0.0061. The mass and radius of the brown dwarf imply an age of 0.46−0.15+0.26 Gyr, however this is inconsistent with the age determined from the host star SED, suggesting that the brown dwarf may be inflated. This is unusual given that its large mass and relatively low levels of irradiation would make it much harder to inflate. NGTS-19b adds to the small, but growing number of brown dwarfs transiting main sequence stars, and is a valuable addition as we begin to populate the so called brown dwarf desert.
@article{arxiv.2105.08574,
title = {NGTS-19b : A high mass transiting brown dwarf in a 17-day eccentric orbit},
author = {Jack S. Acton and Michael R. Goad and Matthew R. Burleigh and Sarah L. Casewell and Hannes Breytenbach and Louise D. Nielsen and Gareth Smith and David R. Anderson and Matthew P. Battley and Daniel Bayliss and François Bouchy and Edward M. Bryant and Szilárd Csizmadia and Phillip Eigmüller and Samuel Gill and Edward Gillen and Nolan Grieves and Maximilian N. Günther and Beth A. Henderson and Simon T. Hodgkin and James A. G. Jackman and James S. Jenkins and Monika Lendl and James McCormac and Maximiliano Moyano and Richard P. Nelson and Ramotholo R. Sefako and Alexis M. S. Smith and Manu Stalport and Jessymol K. Thomas and Rosanna H. Tilbrook and Stéphane Udry and Richard G. West and Peter J. Wheatley and Hannah L. Worters and Jose I. Vines and Douglas R. Alves},
journal= {arXiv preprint arXiv:2105.08574},
year = {2021}
}