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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.
| Spectral Classification of Stars in A Supplement to the Bright Star Catalogue MK spectral types are given for about 584 stars in A Supplement to theBright Star Catalogue. These are compared with Hipparcos parallaxes tocheck the reliability of those classifications. The estimated errors are+/-1.2 subtypes, and 10% of the luminosity classes may be wrong.
| 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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Gözlemler ve gökölçümü verileri
Takýmyýldýz: | Pupa |
Sað Açýklýk: | 07h27m34.48s |
Yükselim: | -18°29'30.8" |
Görünürdeki Parlaklýk: | 6.901 |
Uzaklýk: | 196.464 parsek |
özdevim Sað Açýklýk: | -5.4 |
özdevim Yükselim: | -4.1 |
B-T magnitude: | 6.791 |
V-T magnitude: | 6.892 |
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