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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 (126.96.36.199) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcar?J/A+A/367/521
|Convection, Thermal Bifurcation, and the Colors of A Stars|
Broadband ultraviolet photometry from the TD-1 satellite andlow-dispersion spectra from the short wavelength camera of IUE have beenused to investigate a long-standing proposal of Bohm-Vitense that thenormal main-sequence A and early-F stars may divide into two differenttemperature sequences: (1) a high-temperature branch (and plateau)comprised of slowly rotating convective stars, and (2) a low-temperaturebranch populated by rapidly rotating radiative stars. We find noevidence from either data set to support such a claim, or to confirm theexistence of an "A-star gap" in the B-V color range 0.22 <= B-V <=0.28 due to the sudden onset of convection. We do observe, nonetheless,a large scatter in the 1800--2000 A colors of the A--F stars, whichamounts to ~0.65 mag at a given B-V color index. The scatter is notcaused by interstellar or circumstellar reddening. A convincing case canalso be made against binarity and intrinsic variability due topulsations of delta Sct origin. We find no correlation with establishedchromospheric and coronal proxies of convection, and thus nodemonstrable link to the possible onset of convection among the A--Fstars. The scatter is not instrumental. Approximately 0.4 mag of thescatter is shown to arise from individual differences in surface gravityas well as a moderate spread (factor of ~3) in heavy metal abundance andUV line blanketing. A dispersion of ~0.25 mag remains, which has noclear and obvious explanation. The most likely cause, we believe, is aresidual imprecision in our correction for the spread in metalabundances. However, the existing data do not rule out possiblecontributions from intrinsic stellar variability or from differential UVline blanketing effects owing to a dispersion in microturbulentvelocity.
|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.
|The late A-type stars - Refined MK classification, confrontation with Stromgren photometry, and the effects of rotation|
The MK spectral classification for late A-type stars is refined and theeffects of rotation of spectral classification and uvby(beta) photometryfor these stars are examined. It is found that, for A3 stars, the4417/4481 A wavelength ratio produces results that are inconsistent withthe Stark broadening of the H lines. It is suggested that this ratio isnot useful as a luminosity criterion at any spectral type.Self-consistent sequences of narrow- and broadline standards areestablished. The results of the refined classification system arecompared with Stromgren photometry, showing a set of low-v sin i A-typestars with anomalously large delta(c1) indices for theirluminosity types. It is proposed that these stars are rapid rotatorsseen at fairly low inclination angles.
|Two-colour diagrams for differentially rotating stars|
|Lists of photometric AM candidates|
The Geneva photometric m parameter (Nicolet and Cramer, 1982) is used inorder to select Am photometric candidates from the Rufener (1981)catalogue. Two lists are given, the first containing field stars and thesecond cluster stars. According to the photometric criteria thediffusion process probably responsible for the Am phenomenon takes placerather quickly as Am candidates are present in young clusters. It isconfirmed that the phenomenon is enhanced by low rotational velocity andhigh metallicity. The age seems to slightly affect the Am phenomenon.
|Spectral classification from the ultraviolet line features of S2/68 spectra. III - Early A-type stars|
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1978A&AS...33...15C&db_key=AST
|Rotational Velocities and Spectral Types of Some A-Type Stars|
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1972PASP...84..584L&db_key=AST