New observations and transit solutions of the inflated exoplanets HATP40b and HATP51b
Abstract
We present highprecision photometric observations of the transiting exoplanets HATP40b and HATP51b by the Rozhen 2m telescope. The newlyobserved transit of HATP40b is the first one with a complete curve. The orbital periods of the two targets were improved. We modeled the observed transits and found bigger stellar radii than those derived from the stellar models. The planet radii of HATP40b and HATP51b obtained from our transit solutions are bigger than the values calculated by the empirical relations for Jupitermass and Saturnmass planets respectively. Their values reveal the highlyinflated nature of the two targets, especially that of HATP51b. We established that the best transit solutions correspond to a quadratic limbdarkening law. The fitted limbdarkening coefficients of HATP40 are close to the theoretical ones while those of HATP51 are a little different. The precise astrometric Gaia distances of the two targets are smaller by 6%7% than the calculated values from the stellar models. We propose the Gaia distances to be used for improvement of the stellar models as well as for more reliable calculation of the parameters of the known exoplanets.
 Publication:

Research in Astronomy and Astrophysics
 Pub Date:
 March 2021
 DOI:
 10.1088/16744527/21/2/44
 Bibcode:
 2021RAA....21...44K
 Keywords:

 (Stars:) planetary systems;
 techniques: photometric;
 Stars: individual (HATP40 and HATP51)