We report the discovery of HATS-15 b and HATS-16 b, two massive transiting extrasolar planets orbiting evolved (∼10 Gyr) main-sequence stars. The planet HATS-15 b, which is hosted by a G9V star (V=14.8 mag), is a hot Jupiter with mass of 2.17±0.15MJ and radius of 1.105±0.0.040RJ, and completes its orbit in nearly 1.7 days. HATS-16 b is a very massive hot Jupiter with mass of 3.27±0.19MJ and radius of 1.30±0.15RJ; it orbits around its G3 V parent star (V=13.8 mag) in ∼2.7 days. HATS-16 is slightly active and shows a periodic photometric modulation, implying a rotational period of 12 days which is unexpectedly short given its isochronal age. This fast rotation might be the result of the tidal interaction between the star and its planet.
@article{arxiv.1511.06305,
title = {HATS-15 b and HATS-16 b: Two massive planets transiting old G dwarf stars},
author = {S. Ciceri and L. Mancini and T. Henning and G. Á. Bakos and K. Penev and R. Brahm and G. Zhou and J. D. Hartman and D. Bayliss and A. Jordán and Z. Csubry and M. de Val-Borro and W. Bhatti and M. Rabus and N. Espinoza and V. Suc and B. Schmidt and R. Noyes and A. W. Howard and B. J. Fulton and H. Isaacson and G. W. Marcy and R. P. Butler and P. Arriagada and J. Crane and S. Shectman and I. Thompson and T. G. Tan and J. Lázár and I. Papp and P. Sari},
journal= {arXiv preprint arXiv:1511.06305},
year = {2016}
}