Masses and luminosities of O- and B-type stars and red supergiants
Massive stars are of interest as progenitors of supernovae, i.e.neutron stars and black holes, which can be sources of gravitationalwaves. Recent population synthesis models can predict neutron star andgravitational wave observations but deal with a fixed supernova rate oran assumed initial mass function for the population of massive stars. Here we investigate those massive stars, which are supernovaprogenitors, i.e. with O- and early B-type stars, and also allsupergiants within 3 kpc. We restrict our sample to those massive starsdetected both in 2MASS and observed by Hipparcos, i.e. only those starswith parallax and precise photometry. To determine the luminositieswe calculated the extinctions from published multi-colour photometry,spectral types, luminosity class, all corrected for multiplicity andrecently revised Hipparcos distances. We use luminosities andtemperatures to estimate the masses and ages of these stars usingdifferent models from different authors. Having estimated theluminosities of all our stars within 3 kpc, in particular for all O- andearly B-type stars, we have determined the median and mean luminositiesfor all spectral types for luminosity classes I, III, and V. Ourluminosity values for supergiants deviate from earlier results: Previouswork generally overestimates distances and luminosities compared to ourdata, this is likely due to Hipparcos parallaxes (generally moreaccurate and larger than previous ground-based data) and the fact thatmany massive stars have recently been resolved into multiples of lowermasses and luminosities. From luminosities and effective temperatureswe derived masses and ages using mass tracks and isochrones fromdifferent authors. From masses and ages we estimated lifetimes andderived a lower limit for the supernova rate of ?20 events/Myraveraged over the next 10 Myr within 600 pc from the sun. These data arethen used to search for areas in the sky with higher likelihood for asupernova or gravitational wave event (like OB associations).
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Pulkovo compilation of radial velocities for 35495 stars in a common system.
Not Available
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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.
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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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Absolute proper motions of open clusters. I. Observational data
Mean proper motions and parallaxes of 205 open clusters were determinedfrom their member stars found in the Hipparcos Catalogue. 360 clusterswere searched for possible members, excluding nearby clusters withdistances D < 200 pc. Members were selected using ground basedinformation (photometry, radial velocity, proper motion, distance fromthe cluster centre) and information provided by Hipparcos (propermotion, parallax). Altogether 630 certain and 100 possible members werefound. A comparison of the Hipparcos parallaxes with photometricdistances of open clusters shows good agreement. The Hipparcos dataconfirm or reject the membership of several Cepheids in the studiedclusters. Tables 1 and 2 are only available in electronic form at theCDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/Abstract.html
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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 warped distribution of young stars in the southern Milky Way
From a sample presented by Reed containing OB stars with a heliocentricdistance greater than 5kpc, we have selected those stars with agalactocentric azimuth between 240 deg and 275 deg, i.e. in the regionof the maximum warp in the southern hemisphere. Only nine stars havethese characteristics, but they permit a first, unambiguous detection ofthe southern stellar warp in the Milky Way. This seems to be as large asthe gaseous warp, and does not present evidence of twisting of the lineof nodes. Flaring of the stellar distribution with respect to thecentroid of the HI warp is also noticeable.
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A spectroscopic database for Stephenson-Sanduleak Southern Luminous Stars
A database of published spectral classifications for objects in theStepenson-Sanduleak Luminous Stars in the Southern Milky Way catalog hasbeen compiled from the literature. A total of 6182 classifications for2562 stars from 139 sources are incorporated.
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Distant (r greater than 5 kpc) OB stars in the galaxy
Distances and reddenings have been computed from UBV Beta photometry for1042 stars in the Stephenson and Sanduleak (1971) Catalog of LuminousStars in the Southern Milky Way ('LS' Catalog). The local spiral featureis likely a continuous feature toward Puppis at l approximately equals240 deg, and the Carina feature apparently extends to a distance of some10 kpc from the Sun. Detailed information is presented for 73 LS starsthat appear to be at least 5 kpc from the Sun. Of these, three (LS 1329,2419, and 2598) are close to 1.5 kpc below the galactic plane, and one,LS 607, may be ideally suited as a distant rotation-curve point.Radial-velocity and spectroscopic data would be valuable for theseobjects.
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Photometric analysis of the young open cluster HOGG 16
With UBVRI photoelectric photometry, the open cluster Hogg 16 wasinvestigated. The data analysis shows that the cluster is composed by apoor concentrated central star group of 4 arcmin radius around theCPD-60 deg 4703 star, even though some members may be still found at adistance of 10 arcmin from it. A mean color excess, E(B - V) = 0.44, anda true distance modulus V(O) - M(V) = 11.65, equivalent to a distance ofd = 2130 pc, were derived. So the cluster is placed within theSagittarius arm. Its 'turn-off' point agrees with an age of (25.8 +/-1.5) x 10 exp 6 yr while from core overshooting models it results to be23 x 10 exp 6 yr old. A possible relation with the open cluster Cr 272is briefly discussed.
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Radial velocities for 28 southern young open clusters
Radial velocities for 83 OB-stars in 28 southern young open clusters arepresented. The internal and external accuracy of the data is in goodagreement with results obtained by Ardeberg and Maurice (1977) with thesame equipment. From a comparison with radial velocities existing in theliterature no systematic radial-velocity differences for stars in commonare found.
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Catalog of Luminous Stars in the Southern Coalsack Zone
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1982RMxAA...5..183M&db_key=AST
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Analysis of the results of MK classification of 176 stars in 37 southern open clusters
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1979A&AS...37..345F&db_key=AST
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Southern open stars clusters. III. UBV-Hbeta photometry of 28 clusters between galactic longitudes 297d and 353d
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1973A&AS...10..135M&db_key=AST
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INHABITED SKY
