We present four new light curves of transiting exoplanets WASP-1b and HAT-P-20b, observed within the TASTE (The Asiago Search for Transit timing variations of Exoplanets) project. We re-analyzed light curves from the literature in a homogeneous way, calculating a refined ephemeris and orbital-physical parameters for both objects. WASP-1b does not show any significant Transit Timing Variation signal at the 120 s-level. As for HAT-P-20b, we detected a deviation from our re-estimated linear ephemeris that could be ascribed to the presence of a perturber or, more probably, to a previously unnoticed high level of stellar activity. The rotational period of HAT-P-20 A we obtained from archival data (P_rot ~ 14.5 days), combined with its optical variability and strong emission of CaII H&K lines, is consistent with a young stellar age (< 1 Gyr) and support the hypothesis that stellar activity may be responsible of the measured deviations of the transit times.
@article{arxiv.1405.3288,
title = {TASTE IV. Refining ephemeris and orbital parameters for HAT-P-20b and WASP-1b},
author = {V. Granata and V. Nascimbeni and G. Piotto and L. R. Bedin and L. Borsato and A. Cunial and M. Damasso and L. Malavolta},
journal= {arXiv preprint arXiv:1405.3288},
year = {2015}
}
Comments
7 pages, 4 figures, 3 tables, accepted to Astronomische Nachrichten