XXVI. CoRoT-24: a transiting multiplanet system
R. Alonso, C. Moutou, M. Endl, J. -M. Almenara, E. W. Guenther, M. Deleuil, A. Hatzes, S. Aigrain, M. Auvergne, A. Baglin, P. Barge, A. S. Bonomo, P. Bordé, F. Bouchy, C. Cavarroc, J. Cabrera, S. Carpano, Sz. Csizmadia, W. D. Cochran, H. J. Deeg, R. F. Díaz, R. Dvorak, A. Erikson, S. Ferraz-Mello, M. Fridlund, T. Fruth, D. Gandolfi, M. Gillon, S. Grziwa, T. Guillot, G. Hébrard, L. Jorda, A. Léger, H. Lammer, C. Lovis, P. J. MacQueen, T. Mazeh, A. Ofir, M. Ollivier, T. Pasternacki, M. Pätzold, D. Queloz, H. Rauer, D. Rouan, A. Santerne, J. Schneider, M. Tadeu dos Santos, B. Tingley, R. Titz-Weider, J. Weingrill, G. Wuchterl
Abstract
We present the discovery of a candidate multiply transiting system, the first one found in the CoRoT mission. Two transit-like features with periods of 5.11 and 11.76 d are detected in the CoRoT light curve around a main sequence K1V star of r = 15.1. If the features are due to transiting planets around the same star, these would correspond to objects of 3.7 ± 0.4 and 5.0 ± 0.5 R⊕ , respectively. Several radial velocities serve to provide an upper limit of 5.7 M⊕ for the 5.11 d signal and to tentatively measure a mass of 28+11-11 M⊕ for the object transiting with a 11.76 d period. These measurements imply low density objects, with a significant gaseous envelope. The detailed analysis of the photometric and spectroscopic data serves to estimate the probability that the observations are caused by transiting Neptune-sized planets as much as over 26 times higher than a blend scenario involving only one transiting planet and as much as over 900 times higher than a scenario involving two blends and no planets. The radial velocities show a long-term modulation that might be attributed to a 1.5 MJup planet orbiting at 1.8 AU from the host, but more data are required to determine the precise orbital parameters of this companion.
Keywords
planetary systems – techniques: photometric – techniques: radial velocities – techniques: spectroscopic
Astronomy & Astrophysics
Volume 567, Number of pages A112_1
2014 July
