We report the discovery, by the Next Generation Transit Survey (NGTS), of two hot-Jupiters NGTS-8b and NGTS-9b. These orbit a V = 13.68 K0V star (Teff = 5241 +/- 50 K) with a period of 2.49970 days, and a V = 12.80 F8V star (Teff = 6330 +/- 130 K) in 4.43527 days, respectively. The transits were independently verified by follow-up photometric observations with the SAAO 1.0-m and Euler telescopes, and we report on the planetary parameters using HARPS, FEROS and CORALIE radial velocities. NGTS-8b has a mass, 0.93 +0.04 -0.03 MJ and a radius, 1.09 +/- 0.03 RJ similar to Jupiter, resulting in a density of 0.89 +0.08 -0.07 g cm-3. This is in contrast to NGTS-9b, which has a mass of 2.90 +/- 0.17 MJ and a radius of 1.07 +/- 0.06 RJ , resulting in a much greater density of 2.93 +0.53 -0.49 g cm-3. Statistically, the planetary parameters put both objects in the regime where they would be expected to exhibit larger than predicted radii. However, we find that their radii are in agreement with predictions by theoretical non-inflated models.
@article{arxiv.1911.02814,
title = {NGTS-8b and NGTS-9b: two non-inflated hot-Jupiters},
author = {Jean C. Costes and Christopher A. Watson and Claudia Belardi and Ian P. Braker and Matthew R. Burleigh and Sarah L. Casewell and Philipp Eigmüller and Maximilian N. Günther and James A. G. Jackman and Louise D. Nielsen and Maritza G. Soto and Oliver Turner and David R. Anderson and Daniel Bayliss and François Bouchy and Joshua T. Briegal and Edward M. Bryant and Juan Cabrera and Alexander Chaushev and Szilard Csizmadia and Anders Erikson and Samuel Gill and Edward Gillen and Michael R. Goad and Matthew J. Hooton and James S. Jenkins and James McCormac and Maximiliano Moyano and Didier Queloz and Heike Rauer and Liam Raynard and Alexis M. S. Smith and Andrew P. G. Thompson and Rosanna H. Tilbrook and Stephane Udry and Jose I. Vines and Richard G. West and Peter J. Wheatley},
journal= {arXiv preprint arXiv:1911.02814},
year = {2019}
}
Comments
12 pages, 7 figures, accepted for publication in the Monthly Notices of the Royal Astronomical Society