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Session 75 - 2MASS.
Display session, Wednesday, January 17
North Banquet Hall, Convention Center

[75.12] Proper Motion Objects in the 1992--1994 2MASS Prototype Camera Survey: Filling Out the 25-pc Census

J. D. Kirkpatrick, C. A. Beichman (JPL/IPAC)

The NLTT (New Luyten Two Tenths) Catalogue gives information on 58,845 proper motion stars having \mu > 0.18^\prime\primeyr^-1 and spanning all RAs and Decs. Because of the large data and sky volumes involved, only a very small percentage of these objects has ever been followed up. The eventual all-sky coverage of the 2MASS survey, however, will be able to provide infrared magnitudes for many of these stars which, when combined with the blue and red magnitudes available from the POSS and SERC/ESO sky surveys, will provide long-baseline colors useful for distance, temperature, and luminosity estimates.

This poster describes a preliminary search for NLTT stars contained within the 160 deg^2 surveyed by the 2MASS Prototype Camera during runs on the KPNO 1.3-m between 1992 and 1994. Despite Luyten's poorly cataloged positions for some of the stars (several have POSS-I positions which are arcminutes away from the reported 1950-epoch positions), we have recovered 315 of the 329 NLTT objects falling within the Protocam survey area. These sources span the length of the main sequence, from the bright B dwarf Regulus (\alpha Leonis) down to M dwarfs at the survey limit. Other objects, such as white dwarfs, subdwarfs, and subgiants, are also found.

Of the 315 recovered NLTT stars, 12 are already included in the Third Preliminary Edition of the Catalogue of Nearby Stars, which lists all stars within 25 pc of the Sun. Of the rest, \sim12 more have photometric parallaxes placing them within 25 pc, though they were not previously recognized as being nearby. These statistics suggest that over 2200 new systems will be added to the 25-pc census --- an increase of \sim60% over the current sample --- once all the stars in the NLTT Catalogue are observed by 2MASS. Still, this number represents only a fraction of nearby systems likely to be missing. A more thorough approach, unhampered by kinematic selection criteria, is outlined in the poster by Liebert et al.

Program listing for Wednesday