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HD 18747


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관련 글

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.

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관측 및 측정 데이터

별자리:고래자리
적경:03h00m57.79s
적위:+05°17'16.6"
가시등급:8.138
거리:85.543 파섹
적경상의 고유운동:190.1
적위상의 고유운동:-94.2
B-T magnitude:9.312
V-T magnitude:8.235

천체목록:
일반명   (Edit)
HD 1989HD 18747
TYCHO-2 2000TYC 61-1209-1
USNO-A2.0USNO-A2 0900-00700817
HIPHIP 14054

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