A short-period super-Earth orbiting the M2.5 dwarf GJ 3634

Abstract

We report on the detection of GJ 3634b, a super-Earth of mass m sin i = 7.0[+0.9 over -0.8] M[subscript ⊙] and period P = 2.64561 ± 0.00066 day. Its host star is a M2.5 dwarf, has a mass of 0.45 ± 0.05 M[subscript ⊙], a radius of 0.43 ± 0.03 R[subscript ⊙] and lies 19.8 ± 0.6 pc away from our Sun. The planet is detected after a radial-velocity campaign using the ESO/Harps spectrograph. GJ 3634b had an a priori geometric probability to undergo transit of ~7% and, if telluric in composition, a non-grazing transit would produce a photometric dip of ≲0.1%. We therefore followed-up upon the RV detection with photometric observations using the 4.5-μm band of the IRAC imager onboard Spitzer. Our six-hour long light curve excludes that a transit occurs for 2σ of the probable transit window, decreasing the probability that GJ 3634b undergoes transit to ~0.5%.