SOPHIE velocimetry of Kepler transit candidates. VIII. KOI-205 b: a brown-dwarf companion to a K-type dwarf
Rodrigo F. Díaz, Cilia Damiani, Magali Deleuil, José Manuel Almenara, Claire Moutou, Susana C. C. Barros, Aldo S. Bonomo, François Bouchy, Giovanni Bruno, Guill… 展开作者
Rodrigo F. Díaz, Cilia Damiani, Magali Deleuil, José Manuel Almenara, Claire Moutou, Susana C. C. Barros, Aldo S. Bonomo, François Bouchy, Giovanni Bruno, Guillaume Hébrard, Guillaume Montagnier, Alexandre Santerne
We report the discovery of a transiting brown dwarf companion to KOI-205, a K0 main-sequence star, in a 11.720125-day period orbit. The transits were detected by the Kepler space telescope, and the reflex motion of the star was measured using radial velocity observations obtained with the SOPHIE spectrograph. The atmospheric parameters of the host stars were determined from the analysis of high-resolution, high signal-to-noise ratio ESPaDOns spectra obtained for this purpose. Together with spectrophotometric measurements recovered from the literature, these spectra indicate that the star is a mildly metallic K0 dwarf with Teff 5237 $\pm$ 60 K. The mass of the companion is 39.9 $\pm$ 1.0 MJup and its radius is 0.81 $\pm$ 0.02 RJup, in agreement with current theoretical predictions. This is the first time a bona fide brown dwarf companion is detected in orbit around a star of this type. The formation and orbital evolution of brown dwarf companions is briefly discussed in the light of this new discovery.
We present the radial-velocity follow-up of two Kepler planetary transiting candidates (KOI-189 and KOI-686) carried out with the SOPHIE spectrograph at the Observatoire de Haute Provence. These data promptly discard these objects as viable planet candidates and show that the transiting objects are in the regime of very low-mass stars, where a strong discrepancy between observations and models persists for the mass and radius parameters. By combining the SOPHIE spectra with the Kepler light curve and photometric measurements found in the literature, we obtain a full characterization of the tra…
The Kepler mission has detected transits and occultations of a hot compact object around an early-type star, the Kepler Object of Interest KOI 74. The mass of this transiting object was photometrically assessed in a previous study using the presence of the relativistic beaming effect (so-called `Doppler boosting') in the light curve. Our aim was to provide a spectroscopic validation of this pioneering approach. We measured the radial velocity variations of the A1V star KOI 74 with the SOPHIE spectrograph at the 1.93-m telescope of the Observatoire de Haute-Provence (France). Radial velocity me…
The exoplanet KOI-142b (Kepler-88b) shows transit timing variations (TTVs) with a semi-amplitude of $\sim 12\,$ hours, earning the nickname of "king of transit variations". Only the transit of the planet b was detected in the Kepler data with an orbital period of $\sim 10.92\,$ days and a radius of $\sim 0.36$ R$_{\mathrm{Jup}}$. The TTVs together with the transit duration variations (TDVs) of KOI-142b were analysed by Nesvorny et al. (2013) who found a unique solution for a companion perturbing planet. The authors predicted an outer non-transiting companion, KOI-142c, with a mass of $0.626\pm…
We report the discovery of a new stellar companion in the KOI-13 system. KOI-13 is composed by two fast-rotating A-type stars of similar magnitude. One of these two stars hosts a transiting planet discovered by Kepler. We obtained new radial velocity measurements using the SOPHIE spectrograph at the Observatoire de Haute-Provence that revealed an additional companion in this system. This companion has a mass between 0.4 and 1 Msun and orbits one of the two main stars with a period of 65.831 \pm 0.029 days and an eccentricity of 0.52 \pm 0.02. The radial velocities of the two stars were derived…
We report the discovery of a hot Jupiter transiting a subgiant star with an orbital period of 6.87 days thanks to public photometric data from the Kepler space mission and new radial velocity observations obtained by the SOPHIE spectrograph. The planet KOI-428b with a radius of 1.17 +/- 0.04 RJup and a mass of 2.2 +/- 0.4MJup, orbits around a F5IV star with R* = 2.13 +/- 0.06Rsun, M* = 1.48 +/- 0.06 Msun and Teff = 6510 +/- 100 K. The star KOI-428 is the largest and the most evolved star discovered so far with a transiting planet.
We report the discovery of a long-period brown-dwarf transiting companion of the solar-type star KOI-415. The transits were detected by the Kepler space telescope. We conducted Doppler measurements using the SOPHIE spectrograph at the Observatoire de Haute-Provence. The photometric and spectroscopic signals allow us to characterize a 62.14+-2.69 Mjup, brown-dwarf companion of an evolved 0.94+-0.06 Msun star in a highly eccentric orbit of P = 166.78805+-0.00022 days and e = 0.698+-0.002. The radius of KOI-415 b is 0.79 (-0.07,+0.12) Rjup, a value that is compatible with theoretical predictions …
We present the detection and characterization of the two new transiting, close-in, giant extrasolar planets KOI-200b and KOI-889b. They were first identified by the Kepler team as promising candidates from photometry of the Kepler satellite, then we established their planetary nature thanks to the radial velocity follow-up jointly secured with the spectrographs SOPHIE and HARPS-N. Combined analyses of the whole datasets allow the two planetary systems to be characterized. The planet KOI-200b has mass and radius of 0.68 +/- 0.09 M_Jup and 1.32 +/- 0.14 R_Jup; it orbits in 7.34 days a F8V host s…
We report the discovery of two new transiting hot Jupiters, KOI-135b and KOI-204b, that were previously identified as planetary candidates by Borucki et al. 2011, and, independently of the Kepler team, confirm the planetary nature of Kepler-17b, recently announced by Desert et al. 2011. Radial-velocity measurements, taken with the SOPHIE spectrograph at the OHP, 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…
We report the strategy and results of our radial velocity follow-up campaign with the SOPHIE spectrograph (1.93-m OHP) of four transiting planetary candidates discovered by the Kepler space mission. We discuss the selection of the candidates KOI-428, KOI-410, KOI-552, and KOI-423. KOI-428 was established as a hot Jupiter transiting the largest and the most evolved star discovered so far and is described by Santerne et al. (2011a). KOI-410 does not present radial velocity change greater than 120 m/s, which allows us to exclude at 3 sigma a transiting companion heavier than 3.4 Mjup. KOI-552b ap…
Whereas thousands of transiting giant exoplanets are known today, only a few are well characterized with long orbital periods. Here we present KOI-3680b, a new planet in this category. First identified by the Kepler team as a promising candidate from the photometry of the Kepler spacecraft, we establish here its planetary nature from the radial velocity follow-up secured over two years with the SOPHIE spectrograph at Observatoire de Haute-Provence, France. The combined analysis of the whole dataset allows us to fully characterize this new planetary system. KOI-3680b has an orbital period of 14…
We report the discovery of a new hot-Jupiter, KOI-196b, transiting a solar-type star with an orbital period of 1.855558 days\pm0.6s thanks to public photometric data from the Kepler space mission and new radial velocity observations obtained by the SOPHIE spectrograph mounted on the 1.93-m telescope at the Observatoire de Haute-Provence, France. The planet KOI-196b, with a radius of 0.841\pm0.032 Rjup and a mass of 0.49\pm0.09 Mjup, orbits a G2V star with R* = 0.996\pm0.032 Rsun, M*= 0.94\pm0.09 Msun, [Fe/H] = -0.10\pm0.16 dex, Teff= 5660\pm100 K and an age of 7.7\pm3.4 Gy. KOI-196b is one the…
We report the validation and characterization of three new transiting exoplanets using SOPHIE radial velocities: KOI-614b, KOI-206b, and KOI-680b. KOI-614b has a mass of $2.86\pm0.35~{\rm M_{Jup}}$ and a radius of $1.13^{+0.26}_{-0.18}~{\rm R_{Jup}}$, and it orbits a G0, metallic ([Fe/H]=$0.35\pm0.15$) dwarf in 12.9 days. Its mass and radius are familiar and compatible with standard planetary evolution models, so it is one of the few known transiting planets in this mass range to have an orbital period over ten days. With an equilibrium temperature of $T_{eq}=1000 \pm 45$ K, this places KOI-61…
We present the detection and characterization of the transiting warm Jupiter KOI-12b, first identified with Kepler with an orbital period of 17.86 days. We combine the analysis of Kepler photometry with Doppler spectroscopy and line-profile tomography of time-series spectra obtained with the SOPHIE spectrograph to establish its planetary nature and derive its properties. To derive reliable estimates for the uncertainties on the tomographic model parameters, we devised an empirical method to calculate statistically independent error bars on the time-series spectra. KOI-12b has a radius of 1.43$…
In this paper we report a new transiting warm giant planet: KOI-1257 b. It was first detected in photometry as a planet-candidate by the ${\it Kepler}$ space telescope and then validated thanks to a radial velocity follow-up with the SOPHIE spectrograph. It orbits its host star with a period of 86.647661 d $\pm$ 3 s and a high eccentricity of 0.772 $\pm$ 0.045. The planet transits the main star of a metal-rich, relatively old binary system with stars of mass of 0.99 $\pm$ 0.05 Msun and 0.70 $ \pm $ 0.07 Msun for the primary and secondary, respectively. This binary system is constrained thanks …
Long-period brown dwarf companions detected in radial velocity surveys are important targets for direct imaging and astrometry to calibrate the mass-luminosity relation of substellar objects. Through a 20-year radial velocity monitoring of solar-type stars that began with ELODIE and was extended with SOPHIE spectrographs, giant exoplanets and brown dwarfs with orbital periods longer than ten years are discovered. We report the detection of five new potential brown dwarfs with minimum masses between 32 and 83 Jupiter mass orbiting solar-type stars with periods longer than ten years. An upper ma…
High-precision radial velocity surveys explore the population of low-mass exoplanets orbiting bright stars. This allows accurately deriving their orbital parameters such as their occurrence rate and the statistical distribution of their properties. Based on this, models of planetary formation and evolution can be constrained. The SOPHIE spectrograph has been continuously improved in past years, and thanks to an appropriate correction of systematic instrumental drift, it is now reaching 2 m/s precision in radial velocity measurements on all timescales. As part of a dedicated radial velocity sur…
The coolest dwarf stars targeted by the Kepler Mission constitute a relatively small but scientifically valuable subset of the Kepler target stars, and provide a high-fidelity and nearby sample of transiting planetary systems. Using archival Kepler data spanning the entire primary mission we perform a uniform analysis to extract, confirm and characterize the transit signals discovered by the Kepler pipeline toward M-type dwarf stars. We recover all but two of the signals reported in a recent listing from the Exoplanet Archive resulting in 165 planet candidates associated with a sample of 106 l…
Radial-velocity observations of Kepler candidates obtained with the SOPHIE and HARPS-N spectrographs have permitted unveiling the nature of the five giant planets Kepler-41b, Kepler-43b, Kepler-44b, Kepler-74b, and Kepler-75b, the massive companion Kepler-39b, and the brown dwarf KOI-205b. These companions were previously characterized with long-cadence (LC) Kepler data. Here we aim at refining the parameters of these transiting systems by i) modelling the published radial velocities (RV) and Kepler short-cadence (SC) data that provide a much better sampling of the transits, ii) performing new…
Following Ford et al. (2011, 2012) and Steffen et al. (2012) we derived the transit timing of 1960 Kepler KOIs using the pre-search data conditioning (PDC) light curves of the first twelve quarters of the Kepler data. For 721 KOIs with large enough SNRs, we obtained also the duration and depth of each transit. The results are presented as a catalog for the community to use. We derived a few statistics of our results that could be used to indicate significant variations. Including systems found by previous works, we have found 130 KOIs that showed highly significant TTVs, and 13 that had short-…
We present the Kepler Object of Interest (KOI) catalog of transiting exoplanets based on searching four years of Kepler time series photometry (Data Release 25, Q1-Q17). The catalog contains 8054 KOIs of which 4034 are planet candidates with periods between 0.25 and 632 days. Of these candidates, 219 are new and include two in multi-planet systems (KOI-82.06 and KOI-2926.05), and ten high-reliability, terrestrial-size, habitable zone candidates. This catalog was created using a tool called the Robovetter which automatically vets the DR25 Threshold Crossing Events (TCEs, Twicken et al. 2016). T…
In the frame of the search for extrasolar planets and brown dwarfs around early-type main-sequence stars, we present the detection of a giant planet around the young F-type star HD113337. We estimated the age of the system to be 150 +100/-50 Myr. Interestingly, an IR excess attributed to a cold debris disk was previously detected on this star. The SOPHIE spectrograph on the 1.93m telescope at Observatoire de Haute-Provence was used to obtain ~300 spectra over 6 years. We used our SAFIR tool, dedicated to the spectra analysis of A and F stars, to derive the radial velocity variations. The data …
We confirm the planetary nature of Kepler-412b, listed as planet candidate KOI-202 in the Kepler catalog, thanks to our radial velocity follow-up program of Kepler-released planet candidates, which is on going with the SOPHIE spectrograph. We performed a complete analysis of the system by combining the Kepler observations from Q1 to Q15, to ground-based spectroscopic observations that allowed us to derive radial velocity measurements, together with the host star parameters and properties. We also analyzed the light curve to derive the star's rotation period and the phase function of the planet…
