Contents
Images
Upload your image
DSS Images Other Images
Related articles
Galactic Cepheids. Catalogue of light-curve parameters and distances
We report a new version of the catalogue of distances and light-curveparameters for Galactic classical Cepheids. The catalogue listsamplitudes, magnitudes at maximum light, and intensity means for 455stars in BVRI filters of the Johnson system and (RI)_C filters of theCron-Cousins system. The distances are based on our new multicolour setof PL relations and on our Cepheid-based solution for interstellarextinction law parameters and are referred to an LMC distance modulus of18.25. The catalogue is only available in electronic form at the CDS viaanonymous ftp (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/Abstract.html
| Near infrared light variations of CP stars. The SiSrCrEu stars
Twelve magnetic Chemically Peculiar (CP2) stars of the SiSrCrEu subgroupmostly brighter than the 7.5 visual magnitude have been investigated inthe infrared at 1.25, 1.6 and 2.2 mu . The stars HD 74521, HD 90044, HD119419, HD 125630, and HD 187473 are clearly variable in the nearinfrared with the same period as the visible light, spectrum, andmagnetic field variations. The stars HD 10783, HD 12447, HD 116458, HD147010, HD 166469, HD 170397, and HD 223640 do show a smaller amount ofvariability, although with quite large a dispersion of the data. Aremarkable result of the present investigation is that, at least for thestars for which contemporaneous observations are available, the observedinfrared variations appear to be in phase with the variations in thelong wavelength part of the visible. This may be an indication that themechanism of the infrared variations should be the same as for thevisible. Based on observations collected at the European SouthernObservatory, La Silla, Chile.
| 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 light variations of some southern CP2 stars
Nine southern chemically peculiar stars brighter than the seventh visualmagnitude have been observed in the uvby system. All the stars but HD148199 are previously known light variables, although their periods werenot accurate enough to phase together different kinds of observationscarried out several years apart. Here we present more refined values ofthe period for the stars: HD 74521, HD 90044, HD 119419, HD 125630, HD137509, HD 147010, HD 166469, and HD 170397. The star HD 148199,formerly considered constant in light, has been found to be variable inlight, too, with the same period as the magnetic field.
| The early A type stars - Refined MK classification, confrontation with Stroemgren photometry, and the effects of rotation
The MK classification system for the early A-type stars is refined, anda parallel system of standards for the broad-lined stars is introduced.With this improved system, stars may be classified with significantlygreater precision than before. It is shown that spectral types in thissystem are not systematically affected by rotational line broadening. Atotal of 372 early A-type stars are classified, and a confrontation ofthese spectral types with Stroemgren photometry reveals a number ofsystematic photometric effects of rotation. In particular, high v sin istars are systematically redder than low v sin i stars of the samespectral type, and the beta index is weakened by rotation. It isconcluded that precise spectral classification in conjunction withStroemgren and H-beta photometry can potentially provide a valuablecheck and input to the theory of the atmospheres of rotating stars.
| The A0 stars
A photometric grid, standardized on MK spectral standards, has been usedto compare spectral types and luminosity classes obtainedphotometrically with those in two extensive spectral surveys coveringthe entire sky. Major discrepancies include the spectroscopicclassification of B9.5, which may indicate an otherwise unrecognizedspectral peculiarity, a different A0/A1 spectral type boundary in thetwo samples involved, the well-known misclassification of weak heliumstars, and an appreciable percentage of stars which are called dwarfsspectroscopically but are of higher photometric luminosity. The spacemotion vectors of these stars for which radial velocities are available,and excluding the minimum of 25 percent that are spectroscopic binarieswithout orbital elements, show structure in their distribution in the(U, V)-plane, with members of the Local Association and the Hyades andSirius superclusters forming obvious concentrations. The members of theLocal Association in the samples are mainly old (more than 200 millionyears) mode A stars, although a few much younger stars are included. Themembers of the Hyades and Sirius superclusters contain many bluestragglers, including several peculiar stars of the Hg, Mn, and Sivarieties.
| A photometric study of southern AP stars having right ascensions on the order of 12 HR
The color variability periods of some southern Ap stars were determinedfrom uvby measurements. Observations were made of 25 Sex, HR 4327, betaHya, HD 112381, HR 4965, HR 5158, HR 5269, and HD 125630. Data wereinsufficient for determinations of the periods of the stars HR 4109(which may not vary), l Cen, and the v and y variations of HD 125630.The occurrences of short duration dips in the color variation curves ofseveral of the objects are discussed.
| 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
| UVBY photometry of HD 116994.
Not Available
| Absolute luminosity calibration of Stroemgren's 'intermediate group'
A relation defining the luminosity index for Stroemgren's (1966)intermediate group (A0 to A3 stars) in terms of absolute magnitude iscalibrated using a method based on the principle of maximum likelihood.This relation is also calibrated for the case when the 'a' index iscorrected for reddening. For both relations, calculations are made ofthe magnitude dispersion, the mean velocity components and correspondingdispersion, and the precision of each parameter. The results are shownto be in fairly good agreement with Stroemgren's (1966) values, and arelation incorporating the corrected 'a' index is proposed formain-sequence stars. The absolute magnitudes obtained with a relation ofthe present type are compared with those derived from trigonometricparallaxes and with those obtained by Eggen (1972).
| Four-colour and H BET photometry of some bright southern stars- II.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1972MNRAS.160..155S&db_key=AST
| Line strengths for southern OB stars-II. Observations with moderate dispersion
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1969MNRAS.144...31B&db_key=AST
|
Submit a new article
Related links
Submit a new link
Member of following groups:
|
Observation and Astrometry data
| Constellation: | Centaurus |
| Right ascension: | 13h29m25.20s |
| Declination: | -51°09'55.0" |
| Apparent magnitude: | 5.06 |
| Distance: | 154.56 parsecs |
| Proper motion RA: | -1.8 |
| Proper motion Dec: | -9.2 |
| B-T magnitude: | 5.1 |
| V-T magnitude: | 5.037 |
Catalogs and designations:
|
