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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.
| A new list of 617 radial velocities in four galactic fields
Four stellar fields in the -30 deg galactic latitude have been surveyedfor radial velocities, using a 62 cm objective prism. Exact positions,spectral types, and approximate magnitudes are provided for 617 stars infour different 4 x 4 deg fields. B to F4 stars were found which haveGaussian velocity distributions.
| Vitesse radiales dans 4 Selected Areas.
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| Takýmyýldýz: | Kanatli At |
| Sað Açýklýk: | 22h10m54.45s |
| Yükselim: | +16°36'54.8" |
| Görünürdeki Parlaklýk: | 9.635 |
| özdevim Sað Açýklýk: | -10.2 |
| özdevim Yükselim: | -2.8 |
| B-T magnitude: | 10.08 |
| V-T magnitude: | 9.672 |
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