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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
| On the Variability of G0-G9 Stars
We investigate the Hipparcos Satellite photometry of G0-G9 stars. Mostare not particularly variable over the 3 year observing period, but maybe over a longer time. Stars for which further study is desirable areidentified.
| Quantitative Near-Infrared Spectroscopy of OF and WNL Stars
From new high signal-to-noise ratio (S/N) 1-2.2 μm spectroscopy ofnine extreme early-type stars-including O Iaf, O Iafpe and WN9 types-wedetermine stellar parameters from detailed atmospheric analysis andevaluate results from near-IR analogues of well-known spectraldiagnostics in the optical. We conclude that accurate stellar parameterscan be measured from near-IR spectroscopy alone, an analysis techniqueimportant to studies of luminous stars in the Galactic center and othergalaxies. Derived stellar parameters-mass-loss rates, luminosities,surface abundances, temperatures-show good agreement between optical andnear-IR analyses, provided that IR data are of sufficient spectralresolution (R>2000) and S/N (S/N>30). Wind velocities derived fromHe I 1.0830 μm are consistent with those from ultraviolet P Cygniprofiles. Temperatures 200-1300 K systematically lower are determinedfrom the near-IR diagnostics, a difference not significant indetermining the stellar properties of these objects; which set ofspectral lines provides the more accurate physical parameters-optical orIR-cannot at present be ascertained. The strength of He I 2.0581 μmis very sensitive to the extreme ultraviolet energy distribution whereline blanketing by heavy elements plays an important role; this lineshould not on its own be considered a reliable temperature diagnostic.The three peculiar, extreme emission-line stars-the O Iafpe stars HD152386, HD 152408, and HDE 313846-are more similar in both morphologicaland physical characteristics to WNL-type Wolf-Rayet stars than to normalO Iaf supergiants and should be classified as W-R. Their classificationshould be WN9ha, in which they remain a unique subgroup.
| Lithium in population I subgiants
We present a lithium survey for a sample of 91 Pop. I stars. JHKLphotometry was also obtained for 61 stars in the sample. Besides Liabundances, [Fe/H] values were derived. Thanks to Hipparcos parallaxes,we could infer absolute V magnitudes for our sample stars and were ableto place them on the color-magnitude diagram, which allowed us toconstrain their evolutionary status. Masses and ages were derived formost of the stars by comparison with evolutionary tracks. The sample wasoriginally selected so to include class IV stars later thanspectral-type F0, but, based on the location on the color-magnitudediagram, we found a posteriori that a fraction of the stars (about 20%)are either main sequence stars or evolved giants. As it is the case fordwarfs and giants, a large spread in lithium abundance is present amongthe subgiants in our sample. As expected, the average lithium decreasesas the stars evolve along the subgiant branch; however, there is not aone-to-one relationship between the position on the color-magnitudediagram and lithium abundance, and the observed dispersion is onlypartially explainable as due to a dispersion in mass, metallicity, andage. In particular, a dispersion in lithium is seen among slightlyevolved subgiants with masses close to solar but in the sameevolutionary stage as the G2 IV star beta Hyi. The comparison of thebeta Hyi-like sample with a sample of non evolved solar-like starsindeed suggests that beta Hyi has most likely evolved from a mainsequence Li-rich star, rather than from a Li-poor star (like the Sun)that has dredged-up previously stored lithium. Our sample includesseveral stars that have completed the first-dredge up lithium dilution,but that have not yet evolved to the evolutionary point whereextra-mixing in the giant phase is thought to occur. A large number ofthem have Li abundances considerably below the theoretical predictionsof first dredge-up dilution. We confirm that this is due to the factthat the progenitors of these stars are most likely stars that havedepleted lithium while on the main sequence; the fraction of post-dredgeup Li rich/poor stars, in fact, is consistent with the observeddistribution of Li abundances among stars that have just left the mainsequence. The signature of the second mixing (or RGB extra-mixing)episode is evident in the log n(Li) vs. B-V and log n(Li) vs. M_boldistributions of the stars in the sample; it seems however that theextra-mixing occurs at luminosities lower than predicted by the modelsof Charbonnel (1994). Finally, a few evolved giants are found thatshould have passed the second mixing episode, but that do not show signsof it. At least half of them are spectroscopic binaries. Based onobservations carried out at the European Southern Observatory, La Silla,Chile
| The ROSAT all-sky survey catalogue of optically bright main-sequence stars and subgiant stars
We present X-ray data for all main-sequence and subgiant stars ofspectral types A, F, G, and K and luminosity classes IV and V listed inthe Bright Star Catalogue that have been detected as X-ray sources inthe ROSAT all-sky survey; several stars without luminosity class arealso included. The catalogue contains 980 entries yielding an averagedetection rate of 32 percent. In addition to count rates, sourcedetection parameters, hardness ratios, and X-ray fluxes we also listX-ray luminosities derived from Hipparcos parallaxes. The catalogue isalso available in electronic form via anonymous ftp tocdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/Abstract.html
| F, G and K stars in the ROSAT all-sky survey. I. Photometry
We present accurate BV(RI)_c photometry for a sample of F, G and K starsdetected in selected areas of the ROSAT all-sky survey (RASS). We haveused the photometry, in addition to low-resolution spectroscopy, toestimate spectral classifications, distances and X-ray luminosities. Thelog (L_X / L_V) in the sample lies below -2. Although the samplecontains also nearby, inactive stars, it is dominated by active objects.The median X-ray luminosity in our sample is < L_X > = 29.88 andthe mean value of the hardness ratios = 0.13 +/- 0.35. Wecompare the derived X-ray luminosity function with similar functionsobtained from the serendipitous samples of the Einstein Observatorymedium sensitivity survey (EMSS) and EXOSAT. Our sample is completelyconsistent with the EMSS sample of solar type stars, indicating thatboth our sources and the EMSS sources are representative of the highgalactic latitude X-ray stellar population. We do not find extremelyactive stars (log (L_X) >= 32), as are found in the EMSS sample, andwe argue that these objects are rare. Table 3 is also available inelectronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr(130.79.128.5) or via http://cdsweb.u-strasbg.fr/Abstract.html
| Ca II H and K Filter Photometry on the UVBY System. II. The Catalog of Observations
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1995AJ....109.2828T&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.
| Evolved GK stars near the Sun. 2: The young disk population
From a sample of nearly 2000 GK giants a group of young disk stars withwell determined space motions has been selected. The zero point of theluminosity calibrations, both from the ultraviolet flux (modifiedStroemgren system) and that in the region of 4200 to 4900 A (DDOsystem), show a discontinuity of about a half magnitude at the border ofthe young disk and old disk domains. The population separation is basedon the space velocity components, which are also an age discriminant,with the population interface near 2 x 109 yr, based onmodels with convective overshoot at the core. This age corresponds togiant masses near 1.7 solar mass, near the critical mass separating theyoung stars that do not burn helium in degenerate cores from older starsthat do. Ten percent of both populations show CN anomalies in that thederived value of P(Fe/H) from CN (Cm) and fromFe(M1) differ by more than 0.1 dex and the weak and strong CNstars occur equally in the old disk but the weak CN stars predominate inthe young disk. Peculiar stars, where flux distortions affect theluminosity calibrations, are of the CH+(Ba II) and CH-(weak G band)variety and represent less than 1% of the stars in both populations. Theyoung disk giants are restricted to ages greater than about109 yr, because younger stars are bright giants orsupergiants (luminosity class 2 or 1), and younger than about 2 x109 yr, because the old disk-young disk boundary occurs near1.7 solar mass. The distribution of heavy element abundances, P(Fe/H),for young disk giants is both more limited in range (+/- 0.4 dex) and isskewed toward higher abundances, compared with the nearly normaldistribution for old disk giants. The distribution of (U,V) velocityvectors gives (U,V,W) and their dispersions = (+17.6 +/- 18.4, -14.8 +/-8.4, -6.9 +/- 13.0) and (+3.6 +/- 38.4, -20.7 +/- 27.5, -6.7 +/-17.3)km/s for young and old disk giants, respectively.
| UBV(RI)c observations for 13 bright Cepheids
Photometry in the UBV(RI)c system has been obtained for 13 of thebrightest Cepheids in the southern sky available to the new SydneyUniversity Stellar Interferometer. The stars observed were Eta Aq1, 1Car, U Car, AX Cir, Beta Dor, Zeta Gem, T Mon, Kappa Pav, U Sgr, W Sgr,X Sgr, Y Sgr, and AH Vel. The main purpose of the photometry is toprovide current epoch data for the phases of the variables, although forseveral of the stars these data are also the first in the (RI)c system.
| Large and kinematically unbiased samples of G- and K-type stars. II - Observations of evolved stars in the Bright Star sample. III - Evolved young disk stars in the Bright Star sample
Four color and RI observations were obtained for a large sample ofG-type and K-type stars in the Bright Star Catalogue. Data are firstpresented for 110 evolved stars. Photometry of evolved young diskpopulation stars have then been calibrated for luminosity, reddening,and metallicity on the basis of results for members of the Hyades andSirius superclusters. New DDO results are given for 120 stars.
| Magnitudes and colors for 833 Northern and Southern stars.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1955AJ.....60...65E&db_key=AST
| Photoelectric determination of the colors of 286 stars south of declination -15 degrees.
Not Available
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| קבוצת-כוכבים: | דג זהב |
| התרוממות ימנית: | 05h34m57.60s |
| סירוב: | -61°10'33.0" |
| גודל גלוי: | 6.32 |
| מרחק: | 106.724 פארסק |
| תנועה נכונה: | -6.4 |
| תנועה נכונה: | -26.6 |
| B-T magnitude: | 7.367 |
| V-T magnitude: | 6.405 |
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