K2-287 b: An Eccentric Warm Saturn Transiting a G-dwarf

We report the discovery of K2-287b, a Saturn mass planet orbiting a G-dwarf with a period of P ≈ 15 days. First uncovered as a candidate using K2 campaign 15 data, follow-up photometry and spectroscopy were used to determine a mass {M}_{{P}}=0.317+/- 0.026 {M}_{{J}}, radius {R}_{{P}}=0.833+/- 0.013 {R}_{{J}}, period P=14.893291+/- 0.000025 days, and eccentricity e=0.476+/- 0.026. The host star is a metal-rich V = 11.410 ± 0.129 mag G-dwarf for which we estimate a mass {M}_\star ={1.056}_-0.021^+0.022 {M}_⊙ , radius {R}_\star =1.070+/- 0.010 {R}_⊙ , metallicity [Fe/H] = 0.20 ±0.05, and {T}_eff}=5673+/- 75 K. This warm eccentric planet with a time-averaged equilibrium temperature of {T}_eq}≈ 800 K adds to the small sample of giant planets orbiting nearby stars whose structure is not expected to be affected by stellar irradiation. Follow-up studies on the K2-287 system could help constrain theories of planet migration in close-in orbits.