SWEET-Cat: A catalogue of parameters for Stars With ExoplanETs - I. New atmospheric parameters and masses for 48 stars with planets
TL;DR: In this article, the authors presented a catalogue of stellar parameters for FGK and M stars with planets detected by radial velocity, transit, and astrometry programs, which can be used for statistical studies of the star-planet correlation.
Abstract: Context. Thanks to the importance that the star-planet relation has to our understanding of the planet formation process, the precise determination of stellar parameters for the ever increasing number of discovered extra-solar planets is of great relevance. Furthermore, precise stellar parameters are needed to fully characterize the planet properties. It is thus important to continue the efforts to determine, in the most uniform way possible, the parameters for stars with planets as new discoveries are announced. Aims. In this paper we present new precise atmospheric parameters for a sample of 48 stars with planets. We then take the opportunity to present a new catalogue of stellar parameters for FGK and M stars with planets detected by radial velocity, transit, and astrometry programs. Methods. Stellar atmospheric parameters and masses for the 48 stars were derived assuming local thermodynamic equilibrium (LTE) and using high-resolution and high signal-to-noise spectra. The methodology used is based on the measurement of equivalent widths for a list of iron lines and making use of iron ionization and excitation equilibrium principles. For the catalogue, and whenever possible, we used parameters derived in previous works published by our team, using well-defined methodologies for the derivation of stellar atmospheric parameters. This set of parameters amounts to over 65% of all planet host stars known, including more than 90% of all stars with planets discovered through radial velocity surveys. For the remaining targets, stellar parameters were collected from the literature. Results. The stellar parameters for the 48 stars are presented and compared with previously determined literature values. For the catalogue, we compile values for the effective temperature, surface gravity, metallicity, and stellar mass for almost all the planet host stars listed in the Extrasolar Planets Encyclopaedia. This data will be updated on a continuous basis. The compiled catalogue is available online. The data can be used for statistical studies of the star-planet correlation, as well as for the derivation of consistent properties for known planets.
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TL;DR: In this paper, the authors present empirical measurements of the radii of 116 stars that host transiting planets using only direct observables-the bolometric flux at Earth, the effective temperature, and the parallax provided by the Gaia first data release-and thus are virtually model independent, extinction being the only free parameter.
Abstract: We present empirical measurements of the radii of 116 stars that host transiting planets. These radii are determined using only direct observables-the bolometric flux at Earth, the effective temperature, and the parallax provided by the Gaia first data release-and thus are virtually model independent, extinction being the only free parameter. We also determine each star's mass using our newly determined radius and the stellar density, itself a virtually model independent quantity from previously published transit analyses. These stellar radii and masses are in turn used to redetermine the transiting planet radii and masses, again using only direct observables. The median uncertainties on the stellar radii and masses are ~8% and ~30%, respectively, and the resulting uncertainties on the planet radii and masses are ~9% and ~22%, respectively. These accuracies are generally larger than previously published model-dependent precisions of ~5% and ~6% on the planet radii and masses, respectively, but the newly determined values are purely empirical. We additionally report radii for 242 stars hosting radial-velocity (non-transiting) planets, with median achieved accuracy of ~2%. Using our empirical stellar masses we verify that the majority of putative "retired A stars" in the sample are indeed more massive than ~1.2 Msun. Most importantly, the bolometric fluxes and angular radii reported here for a total of 498 planet host stars-with median accuracies of 1.7% and 1.8%, respectively-serve as a fundamental dataset to permit the re-determination of transiting planet radii and masses with the Gaia second data release to ~3% and ~5% accuracy, better than currently published precisions, and determined in an entirely empirical fashion.
353 citations
TL;DR: In this article, a sample of giant transiting exoplanets detected by the Kepler telescope with orbital periods up to 400 days was used to reveal the nature of these candidates and measure a false positive rate of 54.6 +/- 6.5% for giant-planet candidates orbiting within 400 days of period.
Abstract: While giant extrasolar planets have been studied for more than two decades now, there are still some open questions as to their dominant formation and migration processes, as well as to their atmospheric evolution in different stellar environments. In this paper, we study a sample of giant transiting exoplanets detected by the Kepler telescope with orbital periods up to 400 days. We first defined a sample of 129 giant-planet candidates that we followed up with the SOPHIE spectrograph (OHP, France) in a 6-year radial velocity campaign. This allowed us to unveil the nature of these candidates and to measure a false-positive rate of 54.6 +/- 6.5% for giant-planet candidates orbiting within 400 days of period. Based on a sample of confirmed or likely planets, we then derived the occurrence rates of giant planets in different ranges of orbital periods. The overall occurrence rate of giant planets within 400 days is 4.6 +/- 0.6%. We recovered, for the first time in the Kepler data, the different populations of giant planets reported by radial velocity surveys. Comparing these rates with other yields, we find that the occurrence rate of giant planets is lower only for hot Jupiters but not for the longer-period planets. We also derive a first measurement of the occurrence rate of brown dwarfs in the brown-dwarf desert with a value of 0.29 +/- 0.17%. Finally, we discuss the physical properties of the giant planets in our sample. We confirm that giant planets receiving moderate irradiation are not inflated, but we find that they are on average smaller than predicted by formation and evolution models. In this regime of low-irradiated giant planets, we find a possible correlation between their bulk density and the iron abundance of the host star, which needs more detections to be confirmed.
264 citations
TL;DR: A new upgraded version of ARES is presented, which includes a series of interesting new features such as automatic radial velocity correction, a fully automatic continuum determination, and an estimation of the errors for the equivalent widths.
Abstract: Aims. We present a new upgraded version of ARES. The new version includes a series of interesting new features such as automatic radial velocity correction, a fully automatic continuum determination, and an estimation of the errors for the equivalent widths.Methods. The automatic correction of the radial velocity is achieved with a simple cross-correlation function, and the automatic continuum determination, as well as the estimation of the errors, relies on a new approach to evaluating the spectral noise at the continuum level.Results. ARES v2 is totally compatible with its predecessor. We show that the fully automatic continuum determination is consistent with the previous methods applied for this task. It also presents a significant improvement on its performance thanks to the implementation of a parallel computation using the OpenMP library.
199 citations
TL;DR: In this article, a catalog of panchromatic spectral energy distributions (SEDs) for 7 M and 4 K dwarf stars that span X-ray to infrared wavelengths (5 A −5.5 μm) is presented.
Abstract: We present a catalog of panchromatic spectral energy distributions (SEDs) for 7 M and 4 K dwarf stars that span X-ray to infrared wavelengths (5 A –5.5 μm). These SEDs are composites of Chandra or XMM-Newton data from 5–~50 A, a plasma emission model from ~50–100 A, broadband empirical estimates from 100–1170 A, Hubble Space Telescope data from 1170–5700 A, including a reconstruction of stellar Lyα emission at 1215.67 A, and a PHOENIX model spectrum from 5700–55000 A. Using these SEDs, we computed the photodissociation rates of several molecules prevalent in planetary atmospheres when exposed to each star's unattenuated flux ("unshielded" photodissociation rates) and found that rates differ among stars by over an order of magnitude for most molecules. In general, the same spectral regions drive unshielded photodissociations both for the minimally and maximally FUV active stars. However, for O3 visible flux drives dissociation for the M stars whereas near-UV flux drives dissociation for the K stars. We also searched for an far-UV continuum in the assembled SEDs and detected it in 5/11 stars, where it contributes around 10% of the flux in the range spanned by the continuum bands. An ultraviolet continuum shape is resolved for the star Є Eri that shows an edge likely attributable to Si ii recombination. The 11 SEDs presented in this paper, available online through the Mikulski Archive for Space Telescopes, will be valuable for vetting stellar upper-atmosphere emission models and simulating photochemistry in exoplanet atmospheres.
173 citations
TL;DR: In this paper, the rotation periods of a sample of 48 late F-type to mid-M dwarf stars were determined using time-series high-resolution spectroscopy of the Ca II H&K and H-alpha chromospheric activity indicators.
Abstract: We determine rotation periods of a sample of 48 late F-type to mid-M dwarf stars using time-series high-resolution spectroscopy of the Ca II H&K and H-alpha chromospheric activity indicators. We find good agreement between the rotation periods obtained from each of these two indicators. An empirical relationship between the level of chromospheric emission measured by log (R'HK) and the spectroscopic rotation periods is reported. This relation is largely independent of the spectral type and the metallicity of the stars and can be used to make a reliable prediction of rotation periods for late K to mid-M dwarfs with low levels of activity. For some stars in the sample, the measured spectroscopic rotation periods coincide, or are very close, to the orbital periods of postulated planets. In such cases, further studies are needed to clarify whether the associated periodic radial velocity signals reveal the existence of planets or are due to magnetic activity.
162 citations
References
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TL;DR: The Two Micron All Sky Survey (2MASS) as mentioned in this paper collected 25.4 Tbytes of raw imaging data from two dedicated 1.3 m diameter telescopes located at Mount Hopkins, Arizona and CerroTololo, Chile.
Abstract: Between 1997 June and 2001 February the Two Micron All Sky Survey (2MASS) collected 25.4 Tbytes of raw imagingdatacovering99.998%ofthecelestialsphereinthenear-infraredJ(1.25 � m),H(1.65 � m),andKs(2.16 � m) bandpasses. Observations were conducted from two dedicated 1.3 m diameter telescopes located at Mount Hopkins, Arizona,andCerroTololo,Chile.The7.8sofintegrationtimeaccumulatedforeachpointontheskyandstrictquality control yielded a 10 � point-source detection level of better than 15.8, 15.1, and 14.3 mag at the J, H, and Ks bands, respectively, for virtually the entire sky. Bright source extractions have 1 � photometric uncertainty of <0.03 mag and astrometric accuracy of order 100 mas. Calibration offsets between any two points in the sky are <0.02 mag. The 2MASS All-Sky Data Release includes 4.1 million compressed FITS images covering the entire sky, 471 million source extractions in a Point Source Catalog, and 1.6 million objects identified as extended in an Extended Source Catalog.
12,126 citations
TL;DR: In this article, the authors present an updated version of the AESOPUS code used to compute stellar evolutionary tracks in Padova, which is the result of a thorough revision of put physics, together with the inclusion of the pre-main sequence phase.
Abstract: We present the updated version of the code used to compute stellar evolutionary tracks in Padova. It is the result of a thorough revision of the major in put physics, together with the inclusion of the pre‐main sequence phase, not present in our previous releases of stellar models. Another innovative aspect is the possibility of prompt ly generating accurate opacity tables fully consistent with any selected initial chemical composition, by coupling the OPAL opacity data at high temperatures to the molecular opacities computed with our AESOPUS code (Marigo & Aringer 2009). In this work we present extended sets of stellar evolutionary models for various initial chemical compositions, while other set s with different metallicities and/or different distributions of heavy elements are being computed. For the present release of models we adopt the solar distribution of heavy elements from the recent revision by Caffau et al. (2011), corresponding to a Sun’s metallicity Z≃ 0.0152. From all computed sets of stellar tracks, we also derive isochrones in several photometric systems. The aim is to provide the community with the basic tools to model star clusters and galaxies by means of population synthesis techniques.
3,392 citations
TL;DR: In this work, extended sets of stellar evolutionary models for various initial chemical compositions are presented, while other set s with different metallicities and/or different distributions of heavy elements are being computed.
Abstract: We present the updated version of the code used to compute stellar evolutionary tracks in Padova. It is the result of a thorough revision of the major input physics, together with the inclusion of the pre-main sequence phase, not present in our previous releases of stellar models. Another innovative aspect is the possibility of promptly generating accurate opacity tables fully consistent with any selected initial chemical composition, by coupling the OPAL opacity data at high temperatures to the molecular opacities computed with our AESOPUS code (Marigo & Aringer 2009). In this work we present extended sets of stellar evolutionary models for various initial chemical compositions, while other sets with different metallicities and/or different distributions of heavy elements are being computed. For the present release of models we adopt the solar distribution of heavy elements from the recent revision by Caffau et al. (2011), corresponding to a Sun's metallicity Z=0.0152. From all computed sets of stellar tracks, we also derive isochrones in several photometric systems. The aim is to provide the community with the basic tools to model star clusters and galaxies by means of population synthesis techniques.
3,175 citations
TL;DR: In this paper, the authors identify a subset of 850 stars that have Doppler observations sufficient to detect uniformly all planets with radial velocity semiamplitudes K > 30 m s-1 and orbital periods shorter than 4 yr, and determine that fewer than 3% of stars with -0.5 + 0.3 dex, 25% of observed stars have detected gas giant planets.
Abstract: We have recently carried out spectral synthesis modeling to determine Teff, log g, v sin i, and [Fe/H] for 1040 FGK-type stars on the Keck, Lick, and Anglo-Australian Telescope planet search programs. This is the first time that a single, uniform spectroscopic analysis has been made for every star on a large Doppler planet search survey. We identify a subset of 850 stars that have Doppler observations sufficient to detect uniformly all planets with radial velocity semiamplitudes K > 30 m s-1 and orbital periods shorter than 4 yr. From this subset of stars, we determine that fewer than 3% of stars with -0.5 +0.3 dex, 25% of observed stars have detected gas giant planets. A power-law fit to these data relates the formation probability for gas giant planets to the square of the number of metal atoms. High stellar metallicity also appears to be correlated with the presence of multiple-planet systems and with the total detected planet mass. This data set was examined to better understand the origin of high metallicity in stars with planets. None of the expected fossil signatures of accretion are observed in stars with planets relative to the general sample: (1) metallicity does not appear to increase as the mass of the convective envelopes decreases, (2) subgiants with planets do not show dilution of metallicity, (3) no abundance variations for Na, Si, Ti, or Ni are found as a function of condensation temperature, and (4) no correlations between metallicity and orbital period or eccentricity could be identified. We conclude that stars with extrasolar planets do not have an accretion signature that distinguishes them from other stars; more likely, they are simply born in higher metallicity molecular clouds.
1,624 citations
TL;DR: In this article, the authors presented a catalog of stellar properties for 1040 nearby F, G, and K stars that have been observed by the Keck, Lick, and AAT planet search programs.
Abstract: We present a uniform catalog of stellar properties for 1040 nearby F, G, and K stars that have been observed by the Keck, Lick, and AAT planet search programs. Fitting observed echelle spectra with synthetic spectra yielded effective temperature, surface gravity, metallicity, projected rotational velocity, and abundances of the elements Na, Si, Ti, Fe, and Ni, for every star in the catalog. Combining V-band photometry and Hipparcos parallaxes with a bolometric correction based on the spectroscopic results yielded stellar luminosity, radius, and mass. Interpolating Yonsei-Yale isochrones to the luminosity, effective temperature, metallicity, and α-element enhancement of each star yielded a theoretical mass, radius, gravity, and age range for most stars in the catalog. Automated tools provide uniform results and make analysis of such a large sample practical. Our analysis method differs from traditional abundance analyses in that we fit the observed spectrum directly, rather than trying to match equivalent widths, and we determine effective temperature and surface gravity from the spectrum itself, rather than adopting values based on measured photometry or parallax. As part of our analysis, we determined a new relationship between macroturbulence and effective temperature on the main sequence. Detailed error analysis revealed small systematic offsets with respect to the Sun and spurious abundance trends as a function of effective temperature that would be inobvious in smaller samples. We attempted to remove these errors by applying empirical corrections, achieving a precision per spectrum of 44 K in effective temperature, 0.03 dex in metallicity, 0.06 dex in the logarithm of gravity, and 0.5 km s-1 in projected rotational velocity. Comparisons with previous studies show only small discrepancies. Our spectroscopically determined masses have a median fractional precision of 15%, but they are systematically 10% higher than masses obtained by interpolating isochrones. Our spectroscopic radii have a median fractional precision of 3%. Our ages from isochrones have a precision that varies dramatically with location in the Hertzsprung-Russell diagram. We plan to extend the catalog by applying our automated analysis technique to other large stellar samples.
1,571 citations