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Resolving OB Systems in the Carina Nebula with the Hubble Space Telescope Fine Guidance Sensor
We observed 23 OB stars in the Carina Nebula (NGC 3372) with the HubbleSpace Telescope's Fine Guidance Sensor 1r (FGS1r) in its high angularresolution mode. Five of these OB stars are newly resolved binaries withprojected separations ranging from 0.015" to 0.352" (37 to 880 AU at adistance of 2.5 kpc), and V-band magnitude differences ranging from 0.9to 2.8. The most important astrophysical result is the unexpectedresolution of the prototype O2 If* star HD 93129A as a 55 milliarcsecond(mas) double with a ΔmV of 0.9. This object has servedas a spectroscopic benchmark for the analysis of the most massive hotstars and their winds on the prior assumption that it is a single star.This discovery supports the interpretation of recent radio and X-rayobservations as evidence of colliding-wind phenomena in HD 93129A.Another interesting result is the determination of an upper limit ofabout 35 AU for the projected separation of the binary pairs in thehierarchical double spectroscopic binary HD 93206. The high incidence ofresolved binaries provides motivation for a more thorough, statisticallymeaningful study of multiplicity among the most massive stars in theyoung ionizing clusters of the nebula to obtain a complete sample of thelong-period systems that have evaded spectroscopic detection. However,considering that the nine spectroscopic binaries with accurate orbits inthe Carina Nebula have orbital dimensions <~1 AU, which at a distanceof 2.5 kpc subtends an angle of only 0.4 mas, well below the ~=10 masangular resolution of FGS1r, there remains a significant range oforbital periods and separations over which it is very difficult todetect multiplicity in the nebula with currently available instruments.Based on observations with the NASA/ESA Hubble Space Telescope, obtainedat the Space Telescope Science Institute, which is operated by theAssociation of Universities for Research in Astronomy (AURA), Inc.,under NASA contract NAS 5-26555.
| 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
| 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.
| Catalogue of the energy distribution data in spectra of stars in the uniform spectrophotometric system.
Not Available
| The chemical evolution of the solar neighborhood. I - A bias-free reduction technique and data sample
The possible ways of measuring the age-metallicity relation for thegalactic disk in the neighborhood of the sun are discussed. It is shownthat the use of a field star sample chosen on the basis of effectivetemperature introduces a bias which results in a monotonic increase inthe metal abundance of the disk with time. However, if theage-metallicity relation for the disk can be shown to satisfy certaincriteria, the bias introduced in such a sample can be neglected: thegalactic disk apparently satisfies the criteria. It is concluded that asample analyzed through the use of uvby and H(beta) photometry inconjunction with a self-consistent set of theoretical isochronesprovides the least biased, most accurate estimate of the age-metallicityrelation for the disk.
| Prediction of spectral classification from photometric observations - Application of the UVBY beta photometry and the MK spectra classification. II - General case
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1980A&A....85...93M&db_key=AST
| Absolute luminosity calibration of Stroemgren's 'late group'
A statistical parallax method based on the principle of maximumlikelihood is used to calibrate absolute luminosities for samples ofcooler stars constituting the 'late group' defined by Stromgren (1966).The samples examined include 415 stars of all luminosity classes and asubset comprising 86 main-sequence stars. Linear calibration relationsinvolving the Stromgren beta, (b-y), and bracketted c1 indices arederived which yield mean absolute magnitudes with an accuracy of 0.09magnitude for the overall sample and 0.13 magnitude for themain-sequence subsample. Several second-order relations are considered,and the results are compared with Crawford's (1975) calibrations as wellas with mean absolute magnitudes obtained from trigonometric parallaxes.The possible effect of interstellar absorption on the calibrationrelations is also investigated.
| Four-colour and H BET photometry of some bright southern stars.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1972MNRAS.159..165S&db_key=AST
| Space distribution of stars in the southern Milky Way. I. A region in Nor.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1968AJ.....73..590D&db_key=AST
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תצפית ומידע אסטרומטרי
| קבוצת-כוכבים: | סרגל |
| התרוממות ימנית: | 16h01m06.40s |
| סירוב: | -54°34'40.0" |
| גודל גלוי: | 6.13 |
| מרחק: | 137.363 פארסק |
| תנועה נכונה: | -39.6 |
| תנועה נכונה: | -40.7 |
| B-T magnitude: | 6.424 |
| V-T magnitude: | 6.155 |
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