Contents
Images
Upload your image
DSS Images Other Images
Related articles
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
| 3 Micron Ice-Band Absorption in Young Stellar Objects
Profiles of the 3 mu m ice band with moderate spectral resolution (lambda / Delta lambda = 1300) are presented for four young stellarobjects (YSOs). Of special interest is a comparison between those forthe embedded HH 100 IR source and the FU Orionis star V346 Normae (V346Nor) near HH 57, whose most recent outburst was in 1983. In the newspectra, there is no sign of the absorption feature at 2.97 mu mattributed by Graham & Chen in 1991 to ammonia ice. We now believethat this identification was spurious. The ice band in V346 Nor has aweaker long wavelength wing than that in HH 100 IR. It matches well aprofile observed in the star Elias 13 that lies behind the Taurus darkcloud, and leads to the conclusion that the line of sight to V346 Norpasses through quiescent intracloud material rather than through thedense dust observed in emission at longer wavelengths. Fine structure inthe ice-band wing, probably due to C-H stretch absorption, is detectedat 3.47 mu m in the embedded objects HH 100 IR and [TS84] 13.1 in theCorona Australis cloud but not in V346 Nor. A second dip at 3.55 mu m,which is plausibly linked to CH3OH, is observed in HH 100 IR.
| 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.
| SANTIAGO 91, a right ascension catalogue of 3387 stars (equinox J2000).
The positions in right ascension of 3387 stars belonging to the Santiago67 Catalogue, observed with the Repsold Meridian Circle at Cerro Calan,National Astronomical Observatory, during the period 1989 to 1994, aregiven. The average mean square error of a position, for the wholeCatalogue, is +/-0.009 s. The mean epoch of the catalogue is 1991.84.
| Changing environments of pre-main-sequence stars and their effect on the 3 microns ice feature
Three micron spectra of three premain-sequence stellar objects arepresented. The heavily embedded infrared source HH100-IR, and twooptically visible stars that apparently power the Herbig-Haro objectsHH52, 53, 54, and HH57, are likely to represent different stages duringearly stellar evolution. The medium-resolution spectra of HH100-IRconfirm the existence of a very strong ice band absorption (opticaldepth 0.8-1.2 at 3.07 microns) discovered by Whittet & Blades MNRAS,191, 309 (1980) with lower resolution. Each of the visible stars shows aweaker (optical depth 0.2-0.4) water-ice feature but with a relativelyprominent absorption dip at 2.97 microns which it is believed is due toammonia ice. A detailed inspection of the line profiles suggests thatthe environment around the optically visible stars is significantlywarmer (about 100 K) than that around HH100-IR (about 10-20 K) and thatprocessing of remnant circumstellar dust is already underway.
| 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.
| The S201 far-ultraviolet imaging survey. III - A field in Sagittarius
Far-ultraviolet imagery of a 20 deg diameter field in Sagittarius,centered near (1950) R.A. 18 h 34 m, decl. -30 deg 25 arcmin, wasobtained by the S201 far-ultraviolet camera during the Apollo 16mission. In a 10-minute exposure covering the 1250-1600 A wavelengthrange, 1034 star images are detectable, with a limiting ultravioletmagnitude of about 10. Most of these objects are identified withearly-type stars listed in the Smithsonian Astrophysical ObservatoryStar Catalog, the Catalog of Stellar Identifications, or both, but 203objects remain unidentified or are identified with late-type stars. Thephotometric measurements appear to be in reasonable agreement with thoseof the International Ultraviolet Explorer for stars in common, and withexpectations for A0 stars. A detailed photometric study was made of theMessier 8 region, and it is concluded that dust-scattered starlightcontributes about half of the total radiation observed from the centralregion of M8.
| 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
| 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
| Spectral types and luminosities of B, A and F southern stars
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1957MNRAS.117..449D&db_key=AST
|
Submit a new article
Related links
Submit a new link
Member of following groups:
|
Observation and Astrometry data
| Constellation: | Sagittarius |
| Right ascension: | 19h04m25.10s |
| Declination: | -31°02'49.0" |
| Apparent magnitude: | 5.5 |
| Distance: | 167.504 parsecs |
| Proper motion RA: | 2.8 |
| Proper motion Dec: | -19 |
| B-T magnitude: | 5.525 |
| V-T magnitude: | 5.486 |
Catalogs and designations:
|
INHABITED SKY
