Revised Coordinates and Proper Motions of the Stars in the Luyten Half-Second Catalogue

Abstract

We present refined coordinates and proper motion data for the high proper motion (HPM) stars in the Luyten Half-Second (LHS) catalogue. The positional uncertainty in the original Luyten catalogue is typically >10" and is often >30". We have used the digital scans of the Palomar Observatory Sky Survey (POSS) I and POSS II plates to derive more accurate positions and proper motions of the objects. Out of the 4470 candidates in the LHS catalogue, 4323 objects were manually re-identified in the POSS I and POSS II scans. A small fraction of the stars were not found due to the lack of finder charts and digitized POSS II scans. The uncertainties in the revised positions are typically ~2", but can be as high as ~8" in a few cases; this is a large improvement over the original data. Cross-correlation with the Tycho-2 and Hipparcos catalogues yielded 819 candidates (with m_R < 12). For these brighter sources, the position and proper motion data have been replaced with the more accurate Tycho/Hipparcos data. In total, we have revised proper motion measurements and coordinates for 4040 stars and revised coordinates for 4330 stars, which are presented here.Comment: 108 pages. Accepted for Publication in ApJ Suppl. Some errors caused by the transcription errors in the original LHS catalogue have been corrected in this resubmission. The most current version of the catalogue is also available online at http://www.stsci.edu/~ksahu/lh