INVESTIGADORES
DIAZ Rodrigo Fernando
artículos
Título:
SOPHIE velocimetry of Kepler transit candidates. V. The three hot Jupiters KOI-135b, KOI-204b, and KOI-203b (alias Kepler-17b)
Autor/es:
A. S. BONOMO; G. HÉBRARD; A. SANTERNE; N. C. SANTOS; M. DELEUIL; J. M. ALMENARA; F. BOUCHY; R. F. DÍAZ; C. MOUTOU; M. VANHUYSSE
Revista:
ASTRONOMY AND ASTROPHYSICS
Editorial:
EDP SCIENCES S A
Referencias:
Lugar: Paris; Año: 2012 vol. 538 p. 1 - 11
ISSN:
0004-6361
Resumen:
We report the discovery of two new transiting hot Jupiters, KOI-135b and
KOI-204b, which were previously identified as planetary candidates by
the Kepler team, and independently confirm the planetary nature of
Kepler-17b, recently announced by Désert et al. (2011, ApJS, 197,
14). Radial-velocity measurements, taken with the SOPHIE spectrograph at
the Observatoire de Haute-Provence (France), and Kepler photometry (Q1
and Q2 data) were used to derive the orbital, stellar, and planetary
parameters. KOI-135b and KOI-204b orbit their parent stars in ~3.02 and
3.25 days, respectively. They have approximately the same radius,
Rp = 1.20 ± 0.06 RJup and 1.24 ±
0.07 RJup, but different masses Mp = 3.23 ±
0.19 MJup and 1.02 ± 0.07 MJup. As a
consequence, their bulk densities differ by a factor of four,
ρp = 2.33 ± 0.36 g cm-3 (KOI-135b) and
0.65 ± 0.12 g cm-3 (KOI-204b), meaning that their
interior structures are different. All three planets orbit metal-rich
stars with [Fe/H] ~ 0.3 dex. Our SOPHIE spectra of Kepler-17 were used
both to measure the radial-velocity variations and to determine the
stellar atmospheric parameters, allowing us to refine the
characterisation of the planetary system. In particular we found the
radial-velocity semi-amplitude and the stellar mass to be respectively
slightly smaller and larger than in Désert et al. These two
quantities, however, compensate and lead to a fully consistent planetary
mass. Our analysis gives Mp = 2.47 ± 0.10
MJup and Rp = 1.33 ± 0.04 RJup.
We found evidence of a younger age for this planetary system, t < 1.8
Gyr, which is supported by both evolutionary tracks and gyrochronology.
Finally, we confirm the detection of the optical secondary eclipse by
Désert et al. and also find the brightness phase variation with
the Q1 and Q2 Kepler data. The latter indicates a low redistribution of
stellar heat to the night side (<16% at 1-σ), if the optical
planetary occultation comes entirely from thermal flux. The geometric
albedo is Ag < 0.12 (1-σ).