Oxford Astrophyiscs

Oxford, United Kingdom

Oxford Astrophyiscs

Oxford, United Kingdom
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Alonso R.,Observatoire de Geneva | Alonso R.,Institute of Astrophysics of Canarias | Alonso R.,University of La Laguna | Moutou C.,Aix - Marseille University | And 59 more authors.
Astronomy and Astrophysics | Year: 2014

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 M Jup planet orbiting at 1.8 AU from the host, but more data are required to determine the precise orbital parameters of this companion. © ESO, 2014.

Cavarroc C.,CNRS Paris Institute of Astrophysics | Moutou C.,French National Center for Scientific Research | Gandolfi D.,European Space Agency | Tingley B.,Institute of Astrophysics of Canarias | And 50 more authors.
Astrophysics and Space Science | Year: 2012

CoRoT is a space telescope which aims at studying internal structure of stars and detecting extrasolar planets. We present here a list of transits detected in the light curves of stars observed by CoRoT in two fields in the anti-center direction: the LRa03 one observed during 148 days from 3 October 2009 to 1 March 2010 followed by the SRa03 one from the 5 March 2010 to the 29 March 2010 during 25 days. 5329 light curves for the LRa03 field and 4169 for the SRa03 field were analyzed by the detection team of CoRoT. Then some of the selected exoplanetary candidates have been followed up from the ground. In the LRa03 field, 19 exoplanet candidates have been found, 8 remain unsolved. No secured planet has been found yet. In the SRa03 field, there were 11 exoplanetary candidates among which 6 cases remain unsolved and 3 planets have been found: CoRoT-18b, CoRoT-19b, CoRoT-20b. © 2011 Springer Science+Business Media B.V.

Tal-Or L.,Tel Aviv University | Santerne A.,French National Center for Scientific Research | Mazeh T.,Tel Aviv University | Bouchy F.,French National Center for Scientific Research | And 33 more authors.
Astronomy and Astrophysics | Year: 2011

This paper presents the case of CoRoT LRa02-E2-0121, which was initially classified as a Neptune-size transiting-planet candidate on a relatively wide orbit of 36.3 days. Follow-up observations were performed with UVES, Sandiford, SOPHIE, and HARPS. These observations revealed a faint companion in the spectra. To find the true nature of the system we derived the radial velocities of the faint companion using TODMOR-a two-dimensional correlation technique, applied to the SOPHIE spectra. Modeling the lightcurve with EBAS we discovered a secondary eclipse with a depth of∼0.07%, indicating a diluted eclipsing binary. Combined MCMC modeling of the lightcurve and the radial velocities suggested that CoRoT LRa02-E2-0121 is a hierarchical triple system with an evolved G-type primary and an A-type:F-type grazing eclipsing binary. Such triple systems are difficult to discover. © 2011 ESO.

Gandolfi D.,Thuringer Landessternwarte | Gandolfi D.,European Space Agency | Hebrard G.,University Pierre and Marie Curie | Alonso R.,Observatoire de Geneva | And 57 more authors.
Astronomy and Astrophysics | Year: 2010

The CoRoT exoplanet science team announces the discovery of CoRoT-11b, a fairly massive hot-Jupiter transiting a V = 12.9 mag F6 dwarf star (M* = 1.27±0.05 M⊙, R* = 1.37±0.03 R⊙, Teff = 6440±120 K), with an orbital period of P = 2.994329±0.000011 days and semi-major axis a = 0.0436±0.005 AU. The detection of part of the radial velocity anomaly caused by the Rossiter-McLaughlin effect shows that the transit-like events detected by CoRoT are caused by a planet-sized transiting object in a prograde orbit. The relatively high projected rotational velocity of the star (v sin i = 40±5 km s-1) places CoRoT-11 among the most rapidly rotating planet host stars discovered so far. With a planetary mass of Mp = 2.33±0.34 MJup and radius Rp =1.43±0.03 RJup, the resulting mean density of CoRoT-11b (ρp = 0.99±0.15 g/cm3) can be explained with a model for an inflated hydrogen-planet with a solar composition and a high level of energy dissipation in its interior. © 2010 ESO.

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