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Improved Astrometry and Photometry for the Luyten Catalog. II. Faint Stars and the Revised Catalog
We complete construction of a catalog containing improved astrometry andnew optical/infrared photometry for the vast majority of NLTT starslying in the overlap of regions covered by POSS I and by the secondincremental Two Micron All Sky Survey (2MASS) release, approximately 44%of the sky. The epoch 2000 positions are typically accurate to 130 mas,the proper motions to 5.5 mas yr-1, and the V-J colors to0.25 mag. Relative proper motions of binary components are measured to 3mas yr-1. The false-identification rate is ~1% for11<~V<~18 and substantially less at brighter magnitudes. Theseimprovements permit the construction of a reduced proper-motion diagramthat, for the first time, allows one to classify NLTT stars intomain-sequence (MS) stars, subdwarfs (SDs), and white dwarfs (WDs). We inturn use this diagram to analyze the properties of both our catalog andthe NLTT catalog on which it is based. In sharp contrast to popularbelief, we find that NLTT incompleteness in the plane is almostcompletely concentrated in MS stars, and that SDs and WDs are detectedalmost uniformly over the sky δ>-33deg. Our catalogwill therefore provide a powerful tool to probe these populationsstatistically, as well as to reliably identify individual SDs and WDs.
| The general catalogue of trigonometric [stellar] paralaxes
Not Available
| Parallaxes and proper motions. XVIII
Parallaxes and proper motions are presented for 32 stars in 26starfields. At least 13 of the stars have been designated as subdwarfson the basis of spectral classification. The list consists entirely ofobservations measured on the PDS machine at Yale Observatory. Theexternal standard errors in parallax are about half of those found inprevious lists in this series.
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Osservazione e dati astrometrici
| Costellazione: | Cratere |
| Ascensione retta: | 11h11m47.90s |
| Declinazione: | -15°07'41.5" |
| Magnitudine apparente: | 11.195 |
| Moto proprio RA: | 108.9 |
| Moto proprio Dec: | -293.5 |
| B-T magnitude: | 12.935 |
| V-T magnitude: | 11.339 |
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