HAT-P-42b and HAT-P-43b Two inflated transiting hot Jupiters from the HATNet Survey

Aims. We announce the discovery of two new transiting planets, and provide their accurate initial characterization. Methods. First identified from the HATNet wide-field photometric survey, these candidate transiting planets were then followed-up with a variety of photometric observations. Determining the planetary nature of the objects and characterizing the parameters of the systems were mainly done with the SOPHIE spectrograph at the 1.93m telescope at OHP and the TRES spectrograph at the 1.5m telescope at FLWO. Results. HAT-P-42b and HAT-P-43b are typical hot Jupiters on circular orbits around early-G/late-F main sequence host stars, with periods of 4.641878 +/- 0.000032 and 3.332687 +/- 0.000015 days, masses of 1.044 +/- 0.083 and 0.662 +/- 0.060 M-J, and radii of 1.280 +/- 0.153 and 1.281(0.033)(0.062) R-J, respectively. These discoveries increase the sample of planets with measured mean densities, which are needed to constrain theories of planetary interiors and atmospheres. Moreover, their hosts are relatively bright (V < 13.5), which facilitates further follow-up studies.