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Extrasolar planets and brown dwarfs around A-F type stars. VI. High precision RV survey of early type dwarfs with HARPS
Aims: Systematic surveys to search for exoplanets have been mostlydedicated to solar-type stars sofar. We developed in 2004 a method toextend such searches to earlier A-F type dwarfs and startedspectroscopic surveys to search for planets and quantify the detectionlimit achievable when taking the stars properties (Spectral Type, v sini) and their actual levels of intrinsic variations into account. We givehere the first results of our southern survey with HARPS. Methods: We observed 185 A-F (B-V in the range [-0.1; 0.6]) stars withHARPS and analysed them with our dedicated software. We used severalcriteria to probe different origins for the radial-velocity variations -stellar activity (spots, pulsations) or companions: bisector shape,radial-velocity variations amplitudes, and timescales. Results:1) Sixty-four percent of the 170 stars with enough data points are foundto be variable. Twenty are found to be binaries or candidate binaries(with stars or brown dwarfs). More than 80% of the latest type stars(once binaries are removed), are intrinsically variable at a 2 ms-1 precision level. Stars with earlier spectral type (B-V≤ 0.2) are either variable or associated to levels of uncertaintiescomparable to the RV rms observed on variable stars of the same B-V. 2)We detected one long-period planetary system (presented in anotherpaper) around an F6IV-V star. 3) We quantified the jitter due to stellaractivity and we show that when taking this jitter into account inaddition to the stellar parameters (spectral type, v sin i), it is stillpossible to detect planets with HARPS with periods of 3 days (resp. 10days and 100 days) on 91% (resp. 83%, 61%) of them. We show that eventhe earliest spectral type stars are accessible to this type of search,provided they have a low projected rotational velocity and low levels ofactivity. 4) Taking the present data into account, we computed theactually achieved detection limits for 107 targets and discuss thelimits as a function of B-V. Given the data at hand, our survey issensitive to short-period (few days) planets and to longer ones (100days) to a lower extent (latest type stars). We derive first constrainson the presence of planets around A-F stars for these ranges of periods.Based on observations collected at the European Southern Observatory,Chile, ESO 075.C-0689, 076.C-0279, 077.C-0295, 078.C-0209, 080.C-0664,080.C-0712.
| Pulkovo compilation of radial velocities for 35495 stars in a common system.
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| Vitesses radiales. Catalogue WEB: Wilson Evans Batten. Subtittle: Radial velocities: The Wilson-Evans-Batten catalogue.
We give a common version of the two catalogues of Mean Radial Velocitiesby Wilson (1963) and Evans (1978) to which we have added the catalogueof spectroscopic binary systems (Batten et al. 1989). For each star,when possible, we give: 1) an acronym to enter SIMBAD (Set ofIdentifications Measurements and Bibliography for Astronomical Data) ofthe CDS (Centre de Donnees Astronomiques de Strasbourg). 2) the numberHIC of the HIPPARCOS catalogue (Turon 1992). 3) the CCDM number(Catalogue des Composantes des etoiles Doubles et Multiples) byDommanget & Nys (1994). For the cluster stars, a precise study hasbeen done, on the identificator numbers. Numerous remarks point out theproblems we have had to deal with.
| The calibration of the Stromgren photometric system for A, F and early G supergiants. I - The observational data
An empirical calibration of the Stromgren uvby-beta photometric systemfor the A, F, and early G supergiants is being derived. This paperexplains the observational program and the photometric reductiontechniques used and presents a catalog of new Stromgren photometry forover 600 A, F, and G supergiants.
| Estimation of spectral classifications for bright southern stars with interesting Stromgren indices
This paper investigates the degree of success with which uvby photometrycan be applied to predict spectral classifications for 947 A, F, and Gstars brighter than an apparent magnitude of 8.3 and with four-colorindices indicating some kind of interesting, unusual, or peculiarspectrum. One or several possible spectral classifications are estimatedfor each star from photometry alone, double stars are distinguished, andthe estimates are compared with published classifications. The resultsshow that the framework provided by uvby photometry can be extended toinclude most G and K stars, reddened stars, peculiar stars, and certaintypes of double star.
| Fundamental data for southern stars (First list)
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1957MNRAS.117..534E&db_key=AST
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