Triggered Star Formation by Massive Stars
We present our diagnosis of the role that massive stars play in theformation of low- and intermediate-mass stars in OB associations (theλ Ori region, Ori OB1, and Lac OB1 associations). We find thatthe classical T Tauri stars and Herbig Ae/Be stars tend to line upbetween luminous O stars and bright-rimmed or comet-shaped clouds; thecloser to a cloud the progressively younger they are. Our positional andchronological study lends support to the validity of theradiation-driven implosion mechanism, where the Lyman continuum photonsfrom a luminous O star create expanding ionization fronts to evaporateand compress nearby clouds into bright-rimmed or comet-shaped clouds.Implosive pressure then causes dense clumps to collapse, prompting theformation of low-mass stars on the cloud surface (i.e., the bright rim)and intermediate-mass stars somewhat deeper in the cloud. These starsare a signpost of current star formation; no young stars are seenleading the ionization fronts further into the cloud. Young stars inbright-rimmed or comet-shaped clouds are likely to have been formed bytriggering, which would result in an age spread of several megayearsbetween the member stars or star groups formed in the sequence.
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Pulkovo compilation of radial velocities for 35495 stars in a common system.
Not Available
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UBV beta Database for Case-Hamburg Northern and Southern Luminous Stars
A database of photoelectric UBV beta photometry for stars listed in theCase-Hamburg northern and southern Milky Way luminous stars surveys hasbeen compiled from the original research literature. Consisting of over16,000 observations of some 7300 stars from over 500 sources, thisdatabase constitutes the most complete compilation of such photometryavailable for intrinsically luminous stars around the Galactic plane.Over 5000 stars listed in the Case-Hamburg surveys still lackfundamental photometric data.
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On Space Velocities of Binary Stars in Which One Component Has Experienced a Supernova Explosion
When one component of an evolved binary loses a significant fraction ofits initial mass in a symmetric supernova explosion but remains bound toits companion, the remnant binary recoils with a velocity that can becomparable to the orbital velocity of the supernova precursor. Thisvelocity is enough to explain the observed peculiar space velocitiesand/or distances from the Galactic plane of most X-ray binaries andbinary OB runaway stars. Some exceptions certainly occur, butuncertainties in estimates of velocities and distances, as well asmechanisms other than a popular asymmetric kick, may be responsible formost of the exceptions.
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A Search for Pulsar Companions to OB Runaway Stars
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1996ApJ...461..357S&db_key=AST
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DO OB Runaway Stars Have Pulsar Companions?
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1996AJ....111.1220P&db_key=AST
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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.
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Runaway stars from young star clusters containing initial binaries. II - A mass spectrum and a binary energy spectrum
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1990AJ.....99..608L&db_key=AST
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Empirical temperature calibrations for early-type stars
Three temperature calibrations of suitable photometric quantities havebeen derived for O and B stars. A sample of 120 stars with reliableT(eff.) determinations has been used for establishing each calibration.The different calibrations have been critically discussed and compared.Temperature determinations for 1009 program stars have been obtainedwith an accuracy of the order of 10 percent.
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The binary frequency and origin of the OB runaway stars
A radial velocity survey of the bright northern OB runaway stars hasbeen undertaken to determine the frequency of binary stars in thishigh-velocity group. A total of 634 high-dispersion spectrograms of 36proposed runaway stars were obtained over a two year period.Approximately half of the stars are velocity-variable; these includeseven spectroscopic binaries, one possible beta-Cephei variable, and 10stars with emission lines in their spectra. The latter group containsseven of the eight Be stars observed and three luminous O stars, and itis argued that their variability is caused by nonradial pulsation.Fifteen of the program stars have a peculiar radial velocity greaterthan 30 km/s; five others are probable runaways on the basis of distancefrom the galactic plane and proper motion. Only two of the confirmed andprobable runaways, HD 3950 and HD 198846 (Y Cyg), are binaries, and bothare double-lines systems. New orbital elements are presented for HD 3950and the five new binary systems found among the low-velocity stars. Thestatisical methods used to assess velocity variability and periodicsignals are described in detail. The higher fractional abundance ofrunaways among more massive stars, their binary frequency, and theproperties of the runaway binaries suggest that they obtained their highvelocities through single-binary, binary-binary, or n-body closeencounters during the early dynamical evolution of associations.
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Catalog of O-B stars observed with Tokyo Meridian Circle
A catalog of the O-B stars, selected from 'Blaauw-Parenago' list andRubin's catalog, has been compiled on the FK4 system by the observationsmade with Gautier 8-inch Meridian Circle at the Tokyo AstronomicalObservatory during the period, 1971 to 1979. It contains 1059 stars andwas compiled for the future establishment of high precision propermotions of O-B stars.
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A catalog of ultraviolet interstellar extinction excesses for 1415 stars
Ultraviolet interstellar extinction excesses are presented for 1415stars with spectral types B7 and earlier. The excesses with respect to Vare derived from Astronomical Netherlands Satellite (ANS) 5-channel UVphotometry at central wavelengths of approximately 1550, 1800, 2500, and3300 A. A measure of the excess extinction in the 2200-A extinction bumpis also given. The data are valuable for investigating the systematicsof peculiar interstellar extinction and for studying the character of UVinterstellar extinction in the general direction of stars for which theextinction-curve shape is unknown.
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The S201 far-ultraviolet imaging survey. II - A field in Cygnus
Far-ultraviolet imagery of a region in Cygnus, a 20 deg diameter fieldcentered near (1950) R. A. 21 h 31.2 m decl. +37 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 (effective wavelength 1400 A), 730 star images can be detected,corresponding to a limiting ultraviolet magnitude of about m (1400) =10. Assuming nominal interstellar extinction values in this region nearthe galactic plane, this result corresponds to the detection of A0 Vstars to a distance of 300 pc and of B0 V stars to 1500 pc.Uncertainties in spectral classification and interstellar extinction forindividual objects are probably more significant than calibration ormeasurement errors. Most of the objects detected are identified withstars in the Smithsonian Astrophysical Observatory Star Catalog (1966),or the Catalog of Stellar Identifications (1979) or both, but 87 objectsremain unidentified (or are identified with late-type stars).
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An investigation of the statistical properties and nature of runaway stars
The distribution function of the radial components of the peculiarvelocities of O-stars is derived in order to investigate the kinematicalproperties of runaway stars. Three figures are included which show thenumber of stars taken from a catalog of galactic O-stars, subdividedinto four quality groups as a function of the peculiar radial velocitiesfor all available O-stars, for double stars, and for possible singlestars, respectively. The results are found to be in excellent agreementwith the two most plausible theories for the origin of runaway stars,that is, supernovae in close binary systems or gravitational interactionbetween protostars in collapsing protoclusters. A comparison is madebetween the ages of OB associations and the ages of associated runawaystars.
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The Possibility of the Search for Relativistic Objects Using the Ellipsoidal Variability of the Run-Away Stars
Not Available
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Do OB runaways have collapsed companions ?
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1974ApJ...190..653B&db_key=AST
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Catalogue d'etoiles O et B.
Not Available
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KURZE MITTEILUNG. Zur Expansion der Assoziation Cep III
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Spectroscopic Observations of Runaway Stars
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Photoelectric distances of 461 Northern OB-stars and galactic structure from Hγ- luminosities Author: Beer, A.
Abstract image available at:http://adsabs.harvard.edu/abs/1964MNRAS.128..261B
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On the origin of the O- and B-type stars with high velocities (the "run-away" stars), and some related problems
Not Available
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Coordonnées moyennes de 86 étoiles 0 et B déterminées à l'Observatoire de Paris et réduites sans mouvements proper à l'équinoxe 1950,0
Not Available
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Altersbestimmung offener Sternhaufen
Not Available
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On the Luminosities, Motions, and Space Distribution of the Nearer Northern O-B5 Stars.
Abstract image available at:http://adsabs.harvard.edu/abs/1956ApJ...123..408B
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Expanding Motions in the Lacerta Aggregate.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1953ApJ...117..256B&db_key=AST
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INHABITED SKY
