K2-287b: an Eccentric Warm Saturn transiting a G-dwarf

摘要: We report the discovery of K2-287b, a Saturn mass planet orbiting G-dwarf with period $P \approx 15$ days. First uncovered as candidate using K2 campaign 15 data, follow-up photometry and spectroscopy were used to determine $M_P = 0.317 \pm 0.026$ $M_J$, radius $R_P 0.833 0.013$ $R_J$, 14.893291 0.000025$ days eccentricity $e 0.476 0.026$. The host star is metal-rich $V=11.410 0.129$ mag G dwarf for which we estimate $M_* 1.056$ $M_\odot$, $R_* 1.07 0.01$ $R_\odot$, metallicity [Fe/H] $0.20 0.05$ $T_{eff} 5673 75$ K. This warm eccentric time-averaged equilibrium temperature $T_{eq} 800$ K adds small sample giant planets nearby stars whose structure not expected be affected by stellar irradiation. Follow-up studies on K2-287 system could help in constraining theories migration close-in orbits.