The GAPS Programme with HARPS-N at TNG. XIII. The orbital obliquity of three close-in massive planets hosted by dwarf K-type stars: WASP-43, HAT-P-20 and Qatar-2

摘要: In the framework of GAPS project, we are conducting an observational programme aimed at determination orbital obliquity known transiting exoplanets. The targets selected to probe against a wide range stellar and planetary physical parameters. We exploit high-precision radial velocity (RV) measurements, delivered by HARPS-N spectrograph 3.6m Telescopio Nazionale Galileo, measure Rossiter-McLaughlin (RM) effect in RV time-series bracketing planet transits, refine parameters determinations with out-of-transit data. also analyse new transit light curves obtained several 1-2m class telescopes better constrain fundamental planets parent stars. report here on spectroscopic observations for three very massive close-in giant planets: WASP43b, HATP20b Qatar2b orbiting dwarf K-type stars effective temperature well below 5000K. find lambda = 3.5pm6.8 deg WASP43b -8.0pm6.9 HATP20b, while Qatar2, our faintest target, RM is only marginally detected, though best-fit value 15pm20 agreement previous determination. combination rotational periods derived photometrically, estimate true spin-orbit angle, finding that aligned orbit presents small but significant (Psi=36 _{-12}^{+10} deg). By analyzing CaII H&K chromospheric emission lines HATP20 WASP43, evidence enhanced level activity which possibly induced star-planet interactions.