Almenara, J. M.; Bouchy, F.; Gaulme, P.; Deleuil, M.; Havel, M.; Gandolfi, D.; Deeg, H. J.; Wuchterl, G.; Guillot, T.; Gardes, B.; Pasternacki, T.; Aigrain, S.; Alonso, R.; Auvergne, M.; Baglin, A.; Bonomo, A. S.; Bordé, P.; Cabrera, J.; Carpano, S.; Cochran, W. D.; Csizmadia, Sz.; Damiani, C.; Diaz, R. F.; Dvorak, R.; Endl, M.; Erikson, A.; Ferraz-Mello, S.; Fridlund, M.; Hébrard, G.; Gillon, M.; Guenther, E.; Hatzes, A.; Léger, A.; Lammer, H.; MacQueen, P. J.; Mazeh, T.; Moutou, C.; Ollivier, M.; Ofir, A.; Pätzold, M.; Parviainen, H.; Queloz, D.; Rauer, H.; Rouan, D.; Santerne, A.; Samuel, B.; Schneider, J.; Tal-Or, L.; Tingley, B.; Weingrill, J.
Bibliographical reference
Astronomy and Astrophysics, Volume 555, id.A118, 11 pp.
Description
We report the discovery of two transiting exoplanets, CoRoT-25b and
CoRoT-26b, both of low density, one of which is in the Saturn
mass-regime. For each star, ground-based complementary observations
through optical photometry and radial velocity measurements secured the
planetary nature of the transiting body and allowed us to fully
characterize them. For CoRoT-25b we found a planetary mass of 0.27
± 0.04 MJup, a radius of
1.08-0.10+0.3 RJup and hence a mean
density of 0.15-0.06+0.15 g cm-3. The
planet orbits an F9 main-sequence star in a 4.86-day period, that has a
V magnitude of 15.0, solar metallicity, and an age of
4.5-2.0+1.8-Gyr. CoRoT-26b orbits a slightly
evolved G5 star of 9.06 ± 1.5-Gyr age in a 4.20-day period that
hassolar metallicity and a V magnitude of 15.8. With a mass of 0.52
± 0.05 MJup, a radius of
1.26-0.07+0.13 RJup, and a mean density
of 0.28-0.07+0.09 g cm-3, it belongs to
the low-mass hot-Jupiter population. Planetary evolution models allowed
us to estimate a core mass of a few tens of Earth mass for the two
planets with heavy-element mass fractions of
0.52-0.15+0.08 and
0.26-0.08+0.05, respectively, assuming that a
small fraction of the incoming flux is dissipated at the center of the
planet. In addition, these models indicate that CoRoT-26b is anomalously
large compared with what standard models could account for, indicating
that dissipation from stellar heating could cause this size.
The CoRoT space mission, launched on December 27th 2006, has been
developed and is operated by CNES, with the contribution of Austria,
Belgium, Brazil, ESA (RSSD and Science Programme), Germany and Spain.
Partly based on observations obtained at the European Southern
Observatory at Paranal and La Silla, Chile in programs 083.C-0690(A),
184.C-0639.
Related projects
Helio and Astero-Seismology and Exoplanets Search
The principal objectives of this project are: 1) to study the structure and dynamics of the solar interior, 2) to extend this study to other stars, 3) to search for extrasolar planets using photometric methods (primarily by transits of their host stars) and their characterization (using radial velocity information) and 4) the study of the planetary
Exoplanets and Astrobiology
The search for life in the universe has been driven by recent discoveries of planets around other stars (known as exoplanets), becoming one of the most active fields in modern astrophysics. The growing number of new exoplanets discovered in recent years and the recent advance on the study of their atmospheres are not only providing new valuable
