A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun
Traditionally, runaway stars are O- and B-type stars with large peculiarvelocities. We would like to extend this definition to young stars (upto ?50 Myr) of any spectral type and to identify those present in theHipparcos catalogue by applying different selection criteria, such aspeculiar space velocities or peculiar one-dimensional velocities.Runaway stars are important for studying the evolution of multiple starsystems or star clusters, as well as for identifying the origins ofneutron stars. We compile the distances, proper motions, spectral types,luminosity classes, V magnitudes and B-V colours, and we utilizeevolutionary models from different authors to obtain star ages. We studya sample of 7663 young Hipparcos stars within 3 kpc from the Sun. Theradial velocities are obtained from the literature. We investigate thedistributions of the peculiar spatial velocity and the peculiar radialvelocity as well as the peculiar tangential velocity and itsone-dimensional components and we obtain runaway star probabilities foreach star in the sample. In addition, we look for stars that aresituated outside any OB association or OB cluster and the Galactic planeas well as stars for which the velocity vector points away from themedian velocity vector of neighbouring stars or the surrounding local OBassociation/cluster (although the absolute velocity might be small). Wefind a total of 2547 runaway star candidates (with a contamination ofnormal Population I stars of 20 per cent at most). Thus, aftersubtracting these 20 per cent, the runaway frequency among young starsis about 27 per cent. We compile a catalogue of runaway stars, which isavailable via VizieR.
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Young Stars in the Camelopardalis Dust and Molecular Clouds. I. The Cam OB1 Association
The distribution of dust and molecular clouds in the direction ofGalactic longitudes 132--158° and latitudes ± 12\degr\ isinvestigated. The maps of dust distribution in the area were plottedfrom the following surveys: the star counts in the DSS I database byDobashi et al. (2005), the survey of the average infrared color excessesby Froebrich et al. (2007) and the thermal dust emission survey at 100μ m by Schlegel et al. (1998). The distribution of molecular cloudswas taken from the whole sky CO survey by Dame et al. (2001). All thesesurveys show very similar cloud patterns in the area. Using the radialvelocities of CO, the distances to separate clouds are estimated. Arevised list of the Cam OB1 association members contains 43 stars andthe open cluster NGC 1502. 18 young irregular variable and Hαemission stars are identified in the area. All this proves that the starforming process in the Camelopardalis clouds is still in progress.
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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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Photometry and Classification of Stars Along the Camelopardalis and Perseus Border
Seven-color photometry in the Vilnius system for 309 stars down to 12.5mag in the area along the galactic equator near the Camelopardalis andPerseus border is presented. Photometric spectral and luminosity classesof the stars are determined.
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The Stars in Camelopardalis OB1: Their Distance and Evolutionary History
An investigation is undertaken of the optically identified Population Iobjects in the Cam OB1 region. From the analysis of these objects it isdetermined that the distance to the Cam OB1 stars is 975+/-90 pc. Atheoretical H-R diagram for the Cam OB1 stars reveals that starformation has been going on in the region for1×106-1×108 yr. At present, the mostactive site of star formation is Cam R1, which shows an asymmetry in thedistribution of optically identified Population I objects. The majorityof the pre-main-sequence stars lie in the northern half of theassociation, while the main-sequence stars and evolved stars lie in thesouthern half.
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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 interstellar 217 NM band - A third catalogue of equivalent widths
A catalog of equivalent widths of the 217 nm interstellar absorptionband as well as other parameters characterizing the extinction curve inthe ultraviolet has been compiled for 790 O and B stars. A relativelytight correlation between the equivalent width of the 217 nm band andE(B-V) indicates that the absorber of this band is connected with thepopulation of larger interstellar grains responsible for the visualextinction. The parameter characterizing the amount of extinction in thefar UV is only weakly correlated with E(B-V), a result in accord withthe assumption that a second population of very small grains causes therapid increase of the far-UV extinction.
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Catalog of BV magnitudes and spectral classes of 6000 stars
The present catalog, compiled at the Abastumani Observatory, contains BVmagnitudes and spectral classes of about 6000 stars up to V(lim) = 13.0min five circular areas of 18 sq deg located near the salactic-equatorplane. The catalog is intended for star-statistics studies ofstar-formation regions.
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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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The influence of interstellar absorption on measured strengths of the Balmer discontinuity
The definition of the Balmer-discontinuity strength from observationalspectrophotometric data is discussed in relation to detailed results onthe wavenumber dependence of the interstellar absorption. The break inthe interstellar absorption curve at a wavenumber of about 2.33permicrons is found to introduce systematic errors in many currentlydefined strengths of the Balmer discontinuity. The errors should beproportional to the amount of the color excess caused by interstellarabsorption. Using the interstellar absorption curves established byDivan (1954) and by Nandy (1964) theoretical relations are derivedbetween the amount of interstellar absorption and the correspondinginfluence on the Balmer-discontinuity strength. These linear relationsare confirmed through tests on larger sets of observational data. At thesame time the derived relations are useful as correction formulas.
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A spectrophotometric survey of stars along the Milky Way. IV
In the present paper a catalogue of spectrophotometric quantities,spectral types, monochromatic magnitudes and colour equivalents is givenfor all stars brighter than the magnitude m4400 = 10.5 in aregion of the Milky Way in Perseus. No absorption is found for starscloser than about r = 100 pc. The absorbing clouds are situated atdistances closer than 1 kpc and at about 2.5 kpc in the local arm andthe Perseus arm, respectively. The space between the two arms is freefrom absorption. It is also concluded that the Perseus arm continuesbeyond l = 140 deg, containing not only hydrogen gas but also dust to atleast l = 150 deg), while the content of OB stars decreases abruptly atl = 140 deg.
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Observational Confirmation of a Theory of Stellar Evolution.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1956ApJ...123..267J&db_key=AST
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Interstellar Polarization of 405 Stars.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1954ApJ...120..454H&db_key=AST
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INHABITED SKY
