내용
사진
사진 업로드
DSS Images Other Images
관련 글
Bayesian inference of stellar parameters and interstellar extinction using parallaxes and multiband photometry
Astrometric surveys provide the opportunity to measure the absolutemagnitudes of large numbers of stars, but only if the individualline-of-sight extinctions are known. Unfortunately, extinction is highlydegenerate with stellar effective temperature when estimated frombroad-band optical/infrared photometry. To address this problem, Iintroduce a Bayesian method for estimating the intrinsic parameters of astar and its line-of-sight extinction. It uses both photometry andparallaxes in a self-consistent manner in order to provide anon-parametric posterior probability distribution over the parameters.The method makes explicit use of domain knowledge by employing theHertzsprung-Russell Diagram (HRD) to constrain solutions and to ensurethat they respect stellar physics. I first demonstrate this method byusing it to estimate effective temperature and extinction from BVJHKdata for a set of artificially reddened Hipparcos stars, for whichaccurate effective temperatures have been estimated from high-resolutionspectroscopy. Using just the four colours, we see the expected strongdegeneracy (positive correlation) between the temperature andextinction. Introducing the parallax, apparent magnitude and the HRDreduces this degeneracy and improves both the precision (reduces theerror bars) and the accuracy of the parameter estimates, the latter byabout 35 per cent. The resulting accuracy is about 200 K in temperatureand 0.2 mag in extinction. I then apply the method to estimate theseparameters and absolute magnitudes for some 47 000 F, G, K Hipparcosstars which have been cross-matched with Two-Micron All-Sky Survey(2MASS). The method can easily be extended to incorporate the estimationof other parameters, in particular metallicity and surface gravity,making it particularly suitable for the analysis of the 109stars from Gaia.
| Pulkovo compilation of radial velocities for 35495 stars in a common system.
Not Available
| Faint Blue Objects at High Galactic Latitude. VIII. Performance Characteristics of the US Survey
The US survey has cataloged 3987 objects in seven high Galactic latitudefields according to their optical colors, magnitudes, and morphologiesusing photographic techniques. This paper analyzes the effectiveness ofthe survey at producing finding lists for complete samples of hot starsand quasars that exhibit blue and/or ultraviolet excess (B-UVX) relativeto the colors of halo F and G subdwarf stars. A table of 599spectroscopic identifications summarizes the spectroscopic coverage ofthe US objects that has been accomplished to date. In addition, some ofthe survey plates have been reexamined for objects missed during theoriginal selection, and the literature has been searched for all otherspectroscopically identified blue stars and quasars with z<2.2 thathave been selected by other surveys within the US survey areas. Theseresults are used to estimate empirically both the accuracy of the USsurvey selection boundaries (in color, morphology, and brightness) andthe completeness of the resulting samples of B-UVX US objects withinthose boundaries. In particular, it is shown that the reliability of theUS color classifications is high and that the previously derived USmorphological boundary for the complete selection of unresolved quasarsis accurate. The contribution of color and morphological classificationerrors to B-UVX sample incompleteness is therefore correspondinglysmall. The empirical tests indicate high levels of completeness(95+1-2%) for the samples of US quasars and hotstars isolated within the stated survey selection limits. Errata andimprovements to some of the published catalog data are presented inAppendices.
| 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.
| Catalog of Indidual Radial Velocities, 0h-12h, Measured by Astronomers of the Mount Wilson Observatory
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1970ApJS...19..387A&db_key=AST
| Les vitesses radiales obtenues à l'aide d'un grand prisme objectif de 40 cm de diamètre
Not Available
| La mesure des vitesses radiales au prisme objectif - X - 4e liste de vitesses radiales déterminées au prisme objectif à vision directe
Not Available
| Bergedorfer Spektral-Durchmusterung der 115 noerdlichen Kapteynschen Eichfelder+Bd.3: Eichfeld 44 bis 67, Deklination +30 deg.
Not Available
|
새 글 등록
관련 링크
새 링크 등록
다음 그룹에 속해있음:
|
관측 및 측정 데이터
천체목록:
|
