A short-period super-Earth orbiting the M2.5 dwarf GJ 3634. Detection with HARPS velocimetry and transit search with Spitzer photometry

X. Bonfils (1) , M. Gillon , T. Forveille (1) , X. Delfosse (1) , D. Deming , B. -O. Demory , C. Lovis , M. Mayor , V. Neves (1) , C. Perrier (1) , N. C. Santos , S. Seager , S. Udry , I. Boisse , M. Bonnefoy (1)

1 IPAG - Institut de Planétologie et d'Astrophysique de Grenoble

We report on the detection of GJ 3634b, a super-Earth of mass m sin i = 7.0_{-0.8^+0.9~M_⊕} 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_⊙, a radius of 0.43 ± 0.03 R_⊙ 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%.

Based on observations made with the Harps instrument on the ESO 3.6-m telescope at La Silla Observatory under program IDs 082.C-0718(B) and183.C-0437(A), and observations made with Warm Spitzer under program 60027.Radial-velocity and photometric tables (Tables 2 and 3) are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/528/A111

Mots clés: techniques: radial velocities; stars: late-type; planetary systems

Domaines: Planète et Univers [physics]; Astrophysique [astro-ph]

X. Bonfils, M. Gillon, T. Forveille, X. Delfosse, D. Deming, et al.. A short-period super-Earth orbiting the M2.5 dwarf GJ 3634. Detection with HARPS velocimetry and transit search with Spitzer photometry. Astronomy and Astrophysics - A&A, 2011, 528, ⟨10.1051/0004-6361/201015981⟩. ⟨insu-03625201⟩