|The Stellar Content of Obscured Galactic Giant H II Regions. III. W31|
We present near-infrared (J, H, and K) photometry andmoderate-resolution (λ/Δλ=3000) K-band spectroscopyof the embedded stellar cluster in the giant H II region W31. Four ofthe brightest five cluster members are early O-type stars based on theirspectra. We derive a spectrophotometric distance for W31 of 3.4+/-0.3kpc using these new spectral types and infrared photometry. Thebrightest cluster source at K is a red object that lies in the region ofthe J-H versus H-K color-color plot inhabited by stars with excessemission in the K band. This point source has an H- plus K-band spectrumthat shows no photospheric features, which we interpret as being theresult of veiling by local dust emission. Strong Brackett seriesemission and permitted Fe II emission are detected in this source; thelatter feature is suggestive of a dense inflow or outflow. Thenear-infrared position of this red source is consistent with theposition of a 5 GHz thermal radio source seen in previous high angularresolution VLA images. We also identify several other K-band sourcescontaining excess emission with compact radio sources. These objects mayrepresent stars in the W31 cluster still embedded in their birthcocoons.
|The ROSAT all-sky survey catalogue of optically bright OB-type stars.|
For the detailed statistical analysis of the X-ray emission of hot starswe selected all stars of spectral type O and B listed in the Yale BrightStar Catalogue and searched for them in the ROSAT All-Sky Survey. Inthis paper we describe the selection and preparation of the data andpresent a compilation of the derived X-ray data for a complete sample ofbright OB stars.
|The Relation between Rotational Velocities and Spectral Peculiarities among A-Type Stars|
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1995ApJS...99..135A&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.
|Small-scale structure in the diffuse interstellar medium|
The initial results of a study to probe the small-scale structure in thediffuse interstellar medium (ISM) through IUE and optical observationsof interstellar absorption lines toward both components of resolvablebinary stars is reported. The binaries (Kappa CrA, 57 Aql, 59 And, HR1609/10, 19 Lyn, and Theta Ser) observed with IUE have projected linearseparations ranging from 5700 to 700 Au. Except for Kappa CrA, thestrengths of the interstellar absorption lines toward both components ofthese binaries agree to within 10 percent. In the case of Kappa CrA, theoptically thin interstellar Mg I and Mn II lines are about 50 percentstronger toward Kappa-2 CrA than Kappa-1 CrA. Higher resolutionobservations of interstellar Ca II show that this difference isconcentrated in the main interstellar component at V(LSR) = 9 + or - 2km/s. Interestingly, this velocity corresponds to an intervening cloudthat may be associated with the prominent Loop I shell in the local ISM.Given the separation (23 arcsec) and distance (120 pc) of Kappa CrA, theline strength variations indicate that this cloud has structure onscales of 2800 AU or less.
|Walraven photometry of nearby southern OB associations|
Homogeneous Walraven (VBLUW) photometry is presented for 5260 stars inthe regions of five nearby southern OB associations: Scorpio Centaurus(Sco OB2), Orion OB1, Canis Major OB1, Monoceros OB1, and Scutum OB2.Derived V and (B - V) in the Johnson system are included.
|The local system of early type stars - Spatial extent and kinematics|
Published uvby and H-beta photometric data and proper motions arecompiled and analyzed to characterize the structure and kinematics ofthe bright early-type O-A0 stars in the solar vicinity, with a focus onthe Gould belt. The selection and calibration techniques are explained,and the data are presented in extensive tables and graphs and discussedin detail. The Gould belt stars of age less than 20 Myr are shown togive belt inclination 19 deg to the Galactic plane and node-lineorientation in the direction of Galactic rotation, while the symmetricaldistribution about the Galactic plane and kinematic properties (purecircular differential rotation) of the belt stars over 60 Myr oldresemble those of fainter nonbelt stars of all ages. The unresolveddiscrepancy between the expansion observed in the youngest nearby starsand the predictions of simple models of expansion from a point isattributed to the inhomogeneous distribution of interstellar matter.
|Visual measurements of southern double stars|
A double-star observing program is described which has been started atCordoba with a 30 cm refractor. Usually neglected Index Catalog ofVisual Double Stars (IDS) pairs south of -60 deg are selected forobservation, most of them having been measured only one or two timespreviously. A total of 174 micrometric observations of 78 wide pairs arepresented together with a few measurements of 9 double stars not foundin the IDS. Also reported is a list of 135 additional measurements of 26test stars. By comparison with all earlier observations, an estimate forthe personal equation has been made, which is applied in combinationwith catalogue proper motions to investigate the nature of many of thesepairs.
|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.
|Erratum - Discordances Between SAO and HD Numbers for Bright Stars|
|Spectral classification from the ultraviolet line features of S2/68 spectra. V - Supplement series|
The paper presents the ultraviolet classification of more than 450 B-Aand F spectra obtained with the sky survey telescope mounted on the TD1satellite. Concerning abnormal objects, attention is given to the Bestars, the binary stars, the helium weak stars, and the lambda Booobjects. With regard to Be stars, it is concluded that the 1930 Awavelength feature is linked to the existence of either shell structuresor Fe II emission lines in the visual spectral range. In addition, it issuggested that stellar spectra at wavelengths of 1410, 1610-20 and 2400A are equivalent to the He-weak group in the classical range.
|UVBY photometry of wide visual double stars with B, A and F spectral type- I.|
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1978A&AS...34..453O&db_key=AST
|Is star formation bimodal ? II. The nearest early-type stars.|
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1977PASP...89..187E&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
|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
|Radial velocities of 200 southern B stars|
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1965MNRAS.130..281B&db_key=AST
|On the cause underlying the spectral differences of the stars.|
|On the individual parallaxes of the brighter galactic helium stars in the southern hemisphere, together with considerations on the parallax of stars in general.|