New Estimates of the Solar-Neighborhood Massive Star Birthrate and the Galactic Supernova Rate
The birthrate of stars of masses >=10 Msolar is estimatedfrom a sample of just over 400 O3-B2 dwarfs within 1.5 kpc of the Sunand the result extrapolated to estimate the Galactic supernova ratecontributed by such stars. The solar-neighborhood Galactic-plane massivestar birthrate is estimated at ~176 stars kpc-3Myr-1. On the basis of a model in which the Galactic stellardensity distribution comprises a ``disk+central hole'' like that of thedust infrared emission (as proposed by Drimmel and Spergel), theGalactic supernova rate is estimated at probably not less than ~1 normore than ~2 per century and the number of O3-B2 dwarfs within the solarcircle at ~200,000.
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Catalog of Galactic OB Stars
An all-sky catalog of Galactic OB stars has been created by extendingthe Case-Hamburg Galactic plane luminous-stars surveys to include 5500additional objects drawn from the literature. This work brings the totalnumber of known or reasonably suspected OB stars to over 16,000.Companion databases of UBVβ photometry and MK classifications forthese objects include nearly 30,000 and 20,000 entries, respectively.
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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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The Tokyo PMC catalog 90-93: Catalog of positions of 6649 stars observed in 1990 through 1993 with Tokyo photoelectric meridian circle
The sixth annual catalog of the Tokyo Photoelectric Meridian Circle(PMC) is presented for 6649 stars which were observed at least two timesin January 1990 through March 1993. The mean positions of the starsobserved are given in the catalog at the corresponding mean epochs ofobservations of individual stars. The coordinates of the catalog arebased on the FK5 system, and referred to the equinox and equator ofJ2000.0. The mean local deviations of the observed positions from theFK5 catalog positions are constructed for the basic FK5 stars to comparewith those of the Tokyo PMC Catalog 89 and preliminary Hipparcos resultsof H30.
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The distribution of OB stars in the directions of the stellar associations AUR OB 1 and 2
Forty two OB stars have been observed with the space telescope Glazar at1640 A in an area of about 17 sq deg in the direction of the stellarassociations Aur OB 1 and 2. Twenty five of the observed stars of knownspectral type and with colorimetric data are assigned to four stargroups: a B association at a distance of 600 pc and three O associationsat distances of 1100, 2000 and 3000 pc respectively, designated Aur B0.6, Aur OB 1.1, Aur OB 2.0, and Aur OB 3.0. Fourteen stars of unknownspectral type should be OB or at least early-A-type stars, since theirimages were obtained on photographs taken with Glazar. The latestpossible spectral types of these stars and also of stars for which thespectral types are known only roughly are determined. There is a more orless uniform dust cloud in front of the dense parts of the three distantassociations, which introduces an extinction of about 3.5 mag at 1640 A.
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Ultraviolet extinction towards far OB associations
Stars in the Aur OB-2 and Sco OB-1 associations, located in thedirection of the galactic anticenter and center, respectively, have beenobserved for interstellar extinction. No effects due to changes of graincomposition across such large distances are seen. A star exhibiting apeculiar extinction is found in each association. The properties of theresponsible dust grains are discussed in terms of a two-component dustmixture: graphite and uncoated silicates. The column density both ofgraphite and silicate atoms are found to be higher than in stars of thesame associations exhibiting a regular UV extinction.
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Studies of luminous stars in nearby galaxies. I. Supergiants and O stars in the Milky Way.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1978ApJS...38..309H&db_key=AST
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Studies in Galactic STRUCTURE.II.LUMINOSITY Classification for 1270 Blue Giant Stars.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1955ApJS....2...41M&db_key=AST
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Polarization of Stellar Radiation. III. The Polarization of 841 Stars.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1951ApJ...114..241H&db_key=AST
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A Finding List of O and B Stars of High Luminosity.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1951ApJ...113..141N&db_key=AST
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INHABITED SKY
