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The HARPS search for southern extra-solar planets. XXVII. Seven new planetary systems
We are conducting a planet search survey with HARPS since seven years.The volume-limited stellar sample includes all F2 to M0 main-sequencestars within 57.5 pc, where extrasolar planetary signatures aresystematically searched for with the radial-velocity technics. In thispaper, we report the discovery of new substellar companions of sevenmain-sequence stars and one giant star, detected through multipleDoppler measurements with the instrument HARPS installed on the ESO 3.6m telescope, La Silla, Chile. These extrasolar planets orbit the starsHD 1690, HD 25171, HD 33473A, HD 89839, HD 113538, HD 167677, and HD217786. The already-published giant planet around HD 72659 is alsoanalysed here, and its elements are better determined by the addition ofHARPS and Keck data. The other discoveries are giant planets in distantorbits, ranging from 0.3 to 29 MJup in mass and between 0.7and 10 years in orbital period. The low metallicity of most of these newplanet-hosting stars reinforces the current trend for long-distanceplanets around metal-poor stars. Long-term radial-velocity surveys allowprobing the outskirts of extrasolar planetary systems, althoughconfidence in the solution may be low until more than one orbital periodis fully covered by the observations. For many systems discussed in thispaper, longer baselines are necessary to refine the radial-velocity fitand derive planetary parameters. The radial-velocity time series ofstars BD -114672 and HIP 21934 are also analysed and their behaviourinterpreted in terms of the activity cycle of the star, rather thanlong-period planetary companions.Based on observations made with the HARPS instrument on the ESO 3.6 mtelescope at La Silla Observatory under programme IDs 072.C-0488(E) and085.C-0019.RV data are only available in electronic form at the CDS viaanonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/527/A63
| The effect of activity on stellar temperatures and radii
Context: Recent analyses of low-mass eclipsing binary stars haveunveiled a significant disagreement between the observations andpredictions of stellar structure models. Results show that theoreticalmodels underestimate the radii and overestimate the effectivetemperatures of low-mass stars but yield luminosities that accord withobservations. A hypothesis based upon the effects of stellar activitywas put forward to explain the discrepancies. Aims: In this paper westudy the existence of the same trend in single active stars and providea consistent scenario to explain systematic differences between activeand inactive stars in the H-R diagram reported earlier. Methods: Theanalysis is done using single field stars of spectral types late-K and Mand computing their bolometric magnitudes and temperatures throughinfrared colours and spectral indices. The properties of the stars insamples of active and inactive stars are compared statistically toreveal systematic differences. Results: After accounting for a numberof possible bias effects, active stars are shown to be cooler thaninactive stars of similar luminosity therefore implying a larger radiusas well, in proportions that are in excellent agreement with those foundfrom eclipsing binaries. Conclusions: The present results generalisethe existence of strong radius and temperature dependences on stellaractivity to the entire population of low-mass stars, regardless of theirmembership in close binary systems.Tables 1 and 2 are only available in electronic form at the CDS viaanonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/478/507
| Pulkovo compilation of radial velocities for 35495 stars in a common system.
Not Available
| The component star masses in RW Tri
We use time-resolved spectra of the cataclysmic variable RW Tri in the Iand K bands to determine the orbital velocity of the secondary starusing skew-mapping and cross-correlation techniques respectively. Wefind radial velocity amplitudes of 250 +/- 47 km s-1 in the Iband, and 221 +/- 29 km s-1 in the K band. We also determinethe rotational velocity of the secondary star using the K-band data andfind a Vrot sin i of 120 +/- 20 km s-1. Acombination of these results coupled with an estimate of the effect ofheating on the secondary star suggests a mass ratioM2/M1 in the range 0.6-1.1 the mass ratio rangewith no correction for heating is 0.5-0.8. These lead to most likelyestimates of the primary and secondary star masses in the range 0.4-0.7and 0.3-0.4 Msolar respectively. Further refinement of thestellar masses is hampered by uncertain knowledge of the white dwarforbital velocity, and we discuss evidence that at least some estimatesof the white dwarf velocity are contaminated by non-orbital components.
| Improved Astrometry and Photometry for the Luyten Catalog. II. Faint Stars and the Revised Catalog
We complete construction of a catalog containing improved astrometry andnew optical/infrared photometry for the vast majority of NLTT starslying in the overlap of regions covered by POSS I and by the secondincremental Two Micron All Sky Survey (2MASS) release, approximately 44%of the sky. The epoch 2000 positions are typically accurate to 130 mas,the proper motions to 5.5 mas yr-1, and the V-J colors to0.25 mag. Relative proper motions of binary components are measured to 3mas yr-1. The false-identification rate is ~1% for11<~V<~18 and substantially less at brighter magnitudes. Theseimprovements permit the construction of a reduced proper-motion diagramthat, for the first time, allows one to classify NLTT stars intomain-sequence (MS) stars, subdwarfs (SDs), and white dwarfs (WDs). We inturn use this diagram to analyze the properties of both our catalog andthe NLTT catalog on which it is based. In sharp contrast to popularbelief, we find that NLTT incompleteness in the plane is almostcompletely concentrated in MS stars, and that SDs and WDs are detectedalmost uniformly over the sky δ>-33deg. Our catalogwill therefore provide a powerful tool to probe these populationsstatistically, as well as to reliably identify individual SDs and WDs.
| The Palomar/MSU Nearby Star Spectroscopic Survey. III. Chromospheric Activity, M Dwarf Ages, and the Local Star Formation History
We present high-resolution echelle spectroscopy of 676 nearby M dwarfs.Our measurements include radial velocities, equivalent widths ofimportant chromospheric emission lines, and rotational velocities forrapidly rotating stars. We identify several distinct groups by theirHα properties and investigate variations in chromospheric activityamong early (M0-M2.5) and mid (M3-M6) dwarfs. Using a volume-limitedsample together with a relationship between age and chromosphericactivity, we show that the rate of star formation in the immediate solarneighborhood has been relatively constant over the last 4 Gyr. Inparticular, our results are inconsistent with recent large bursts ofstar formation. We use the correlation between Hα activity and ageas a function of color to set constraints on the properties of L and Tdwarf secondary components in binary systems. We also identify a numberof interesting stars, including rapid rotators, radial velocityvariables, and spectroscopic binaries. Observations were made at the 60inch telescope at Palomar Mountain, which is jointly owned by theCalifornia Institute of Technology and the Carnegie Institution ofWashington.
| Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS) - Third edition - Comments and statistics
The Catalogue, available at the Centre de Données Stellaires deStrasbourg, consists of 13 573 records concerning the results obtainedfrom different methods for 7778 stars, reported in the literature. Thefollowing data are listed for each star: identifications, apparentmagnitude, spectral type, apparent diameter in arcsec, absolute radiusin solar units, method of determination, reference, remarks. Commentsand statistics obtained from CADARS are given. The Catalogue isavailable in electronic form at the CDS via anonymous ftp tocdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcar?J/A+A/367/521
| Photometric Measurements of the Fields of More than 700 Nearby Stars
In preparation for optical/IR interferometric searches for substellarcompanions of nearby stars, we undertook to characterize the fields ofall nearby stars visible from the Northern Hemisphere to determinesuitable companions for interferometric phase referencing. Because theKeck Interferometer in particular will be able to phase-reference oncompanions within the isoplanatic patch (30") to about 17th magnitude atK, we took images at V, r, and i that were deep enough to determine iffield stars were present to this magnitude around nearby stars using aspot-coated CCD. We report on 733 fields containing 10,629 measurementsin up to three filters (Gunn i, r and Johnson V) of nearby stars down toabout 13th magnitude at V.
| The Palomar/MSU Nearby Star Spectroscopic Survey.II.The Southern M Dwarfs and Investigation of Magnetic Activity
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1996AJ....112.2799H&db_key=AST
| 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 Palomar/MSU Nearby-Star Spectroscopic Survey. I. The Northern M Dwarfs -Bandstrengths and Kinematics
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1995AJ....110.1838R&db_key=AST
| The mass ratio of the cataclysmic variable AM Herculis.
We present far red time-resolved spectroscopy of the cataclysmicvariable AM Herculis. We measure the radial velocity semi-amplitude ofthe secondary component to be 198+/-3km/s and the projected rotationalvelocity of this star to be 92+/-9km/s. Thus we are able to estimate theratio of component masses to be 0.47+/-0.08. We show, however, thatthese measurements are likely to be biased by ionization of the innersecondary surface by radiation originating close to the shock regionabove the surface of the primary. Using models of the Na surfacedistribution on the secondary star, we attempt to produce a less biasedorbital parameter solution. These results indicate that theuncertainties in the measured, irradiation-affected parameters are toolarge to produce a well-constrained, corrected orbital solution with ourlimited spectral information. However, the method employed to make theirradiation correction has potential to produce accurate binaryparameters given improved data.
| The very low-mass main sequence in the Galactic cluster Praesepe
We present a detailed analysis of the very low-mass main-sequencemembership of the Galactic cluster Praesepe. Spectra of a small sampleof the membership list show them to be M dwarfs, as inferred from thephotometry and proper motions. When combined with data from higher massstars, mass segregation is clearly indicated. Luminosity and massfunctions, corrected for incomplete spatial sampling, are generated andshown to be similar to those of the Pleiades and field. The massfunction is rising at the lowest masses - extrapolation of this risingmass function implies a large population of brown dwarfs.
| The general catalogue of trigonometric [stellar] paralaxes
Not Available
| M dwarf spectra from 0.6 to 1.5 micron - A spectral sequence, model atmosphere fitting, and the temperature scale
Red/infrared (0.6-1.5 micron) spectra are presented for a sequence ofwell-studied M dwarfs ranging from M2 through M9. A variety oftemperature-sensitive features useful for spectral classification areidentified. Using these features, the spectral data are compared torecent theoretical models, from which a temperature scale is assigned.The red portion of the model spectra provide reasonably good fits fordwarfs earlier than M6. For layer types, the infrared region provides amore reliable fit to the observations. In each case, the wavelengthregion used includes the broad peak of the energy distribution. For agiven spectral type, the derived temperature sequence assigns highertemperatures than have earlier studies - the difference becoming morepronounced at lower luminosities. The positions of M dwarfs on the H-Rdiagram are, as a result, in closer agreement with theoretical tracks ofthe lower main sequence.
| Infrared colors of low-mass stars
A total of 322 red dwarf stars are studied in a review of IR IJHKphotometry to discern chromospheric activity and kinematic dataregarding metallicity effects in the IR color:color diagrams. Themetallicity variations are employed to assess changes in the H(-)continuum opacity and water-vapor characterizations. The stars areclassified in terms of metal-richness with five categories includingyoung disk, old disk, and halo types with attention given to the inverserelationship between metallicity and water-band absorption strength. Theresults include IR photometric parallax relations for each metallicitygroup and absolute magnitudes for single stars as well as temperatures,intrinsic colors, and spectral types. The body of data is useful forconstraining models of the interiors and atmospheres of this class ofstars.
| The 8190-A Sodium Doublet in Cataclysmic Variables - Part Two - too Cool for Comfort
In this paper we present the results of time-resolved spectroscopy inthe near-infrared of five cataclysmic variables: U Gem, SS Aur, BDPav, DO Dra and CN Ori. The spectral region observed was chosen tocover the Na 1 doublet at ?8190 Å which is strong inlate-type dwarfs. Radial-velocity curves were measured for thesecondary stars and values for Kabs determined for eachobject. For DO Dra an improved orbital period of 3.969±0.003 hrwas derived.U Gem and SS Aur showed significant apparent eccentricities of0.027±0.012 and 0.17±0.07, respectively. This distortionof the radial-velocity curve is probably caused by line quenching dueto irradiation of the secondary, or contamination of the spectrum byemission from the disc, or a combination of the two. For U Gem theapparent eccentricity was used to correct the observed Kabsfor these effects. Mass ranges were derived for all the objects. For U Gem, which has themost closely constrained result, the secondary mass is larger thanpredicted using main-sequence mass-period relations. Spectral-typeestimates for U Gem and DO Dra are also later than expected if thesecondary obeys an empirical main-sequence mass-radius relation. It isconcluded that the assumption of main-sequence status for thesecondary star should be used with caution.
| BVRI photometry of the Gliese Catalogue stars
Photoelectri BVRI photometry on the Cousins (Kron-Cape) system has beenobtained for many of the southern faint stars in the Gliese Catalog(1969). This extends the work of Cousins (1980) and provides a uniformset of data for the nearby stars. Several red dwarfs are noted, whichwere used to define the red end of the Cousins system.
| UBV (RI)c photometry of faint nearby stars.
Not Available
| U.S. Naval Observatory parallaxes of faint stars - List VIII
The paper presents trigonometric parallaxes, relative proper motions,and photoelectric photometry for 98 stars in 95 astrometric plateseries. These values were determined using plate material obtained withthe 1.55-m astrometric reflector. The results of perturbation analysesfor W922 are presented.
| G. P. Kuiper's spectral classifications of proper-motion stars
Spectral classifications are listed for over 3200 stars, mainly of largeproper motion, observed and classified by Kuiper during the years1937-1944 at the Yerkes and McDonald Observatories. While Kuiper himselfpublished many of his types, and while improved classifications are nowavailable for many of these stars, much of value remains. For many ofthe objects, no other spectral data exist.
| Predicted infrared brightness of stars within 25 parsecs of the sun
Procedures are given for transforming selected optical data intoinfrared flux densities or irradiances. The results provide R, T(eff)blackbody approximations for about 2000 of the stars in Woolley et al.'sCatalog of Stars (1970) within 25 pc of the sun, and additional whitedwarfs, with infrared flux densities predicted for them at ninewavelengths from 2.2 to 101 microns including the Infrared AstronomySatellite bands.
| Studies of late-type dwarfs. V - Theoretical models for lower main-sequence stars
New theoretical stellar models for the lower end of the main sequencehave been computed for a wide range in metallicity. These models arebased on new low-temperature opacities, which include the contributionsfrom the most important molecules, as well as published modelatmospheres, which guided the choice of surface boundary conditions.While the present treatment of the nonideal gas effects is onlyapproximate, reasonable agreement is found with those models comuputedwith a more sophisticated equation of state for solar-like composition.The results are compared with the available observations of late-typedwarfs on both the (M(bol), log T(eff)- and (M(bol), mass)-planes, andsatisfactory agreement is found. In particular, some preliminaryobservational data appear to be consistent with the model predictionthat the most metal-poor subdwarfs should be up to 3 mag subluminous onthe theoretical H-R diagram.
| Kinematical and orbital properties for selected southern high-velocity stars
Using the model of the Galaxy presented by Eggen, Lynden-Bell, andSandage (1962), plane galactic orbits have been calculated for severalsouthern high-velocity stars which possess parallax, proper motion, andradial velocity data. Extensive lists of both raw and computed data forthese stars are included. Published values of U-B and B-V for some ofthese stars were used in plots of each of the orbital parameters versusU-B, B-V, or the ultraviolet excess. Also, a comparison is made betweenthe H-R diagrams for the southern high-velocity star group and that ofM3, a globular cluster, and again for M67, an old open cluster. Thehigh-velocity star group is found to resemble an old open cluster morethan a globular cluster.
| Infrared observations and the structure of the lower main sequence.
Abstract image available at:http://adsabs.harvard.edu/abs/1976ApJ...208..399M
| M dwarfs: band strengths in halo and disk populations.
Abstract image available at:http://adsabs.harvard.edu/abs/1976ApJ...207..535M
| Spectral Types of M Dwarf Stars
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1974ApJS...28....1J&db_key=AST
| Luminosities and temperatures of M dwarf stars from infrared photometry
Bolometric magnitudes for a large number of M type dwarf stars, obtainedby broadband infrared photometry at 1.65, 2.2, and 3.5 microns, arereviewed. The data obtained indicate that one parameter is sufficient todescribe the blanketing in all of the UBVRI bands for all types of Mdwarfs. In general, late M dwarfs seem to have lower effectivetemperatures than are predicted by theoretical models.
| Dwarf K and M stars in the southern hemisphere.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1972AJ.....77..486U&db_key=AST
| Luminosities, Temperatures, and Kinematics of K-Type Dwarfs
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1971ApJS...22..389E&db_key=AST
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Pozíciós és asztrometriai adatok
| Csillagkép: | Pajzs |
| Rektaszcenzió: | 18h33m28.83s |
| Deklináció: | -11°38'09.7" |
| Vizuális fényesség: | 10.001 |
| Távolság: | 25.419 parszek |
| RA sajátmozgás: | -288.5 |
| Dec sajátmozgás: | -234.3 |
| B-T magnitude: | 11.561 |
| V-T magnitude: | 10.13 |
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