High proper motion stars in Kapteyn Selected Area 94 |
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| Authors: | J A Cooke I Neill Reid |
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| Institution: | Institute for Astronomy, University of Edinburgh, Blackford Hill, Edinburgh EH9 3HJ;Department of Physics &Astronomy, University of Pennsylvania, 209 S. 33rd Street, Philadelphia, PA 19104-6396, USA |
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| Abstract: | We have applied the astrometric techniques devised by Murray for analysis of 48-inch Schmidt photographic data to SuperCOSMOS scans of UK Schmidt plates centred on Kapteyn's Selected Area 94 ( α =2h 53m, δ =0°). In this preliminary study, we combine astrometric data from four short-exposure V -band plates, taken in 1987 August (2 plates) and 1993 August (2 plates), with BVRI photometry from sky-limited plate material, to identify stars with proper motions exceeding 0.1 arcsec yr?1. This paper discusses the completeness of the resulting sample and presents spectroscopy of 30 stars with μ >0.2 arcsec yr?1. Based on the latter observations and the distribution in the H V , ( V ? I )] reduced proper-motion diagram, we have classified stars in the complete sample as candidate white dwarfs, main-sequence dwarfs and halo subdwarfs, and derived estimates of the disc and halo luminosity functions. |
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| Keywords: | stars: low‐mass brown dwarfs stars: luminosity function mass function astrometry/subdwarfs Galaxy: structure |
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