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REVISEDLHS - Revised Luyten Half-Second (LHS) Catalog

HEASARC
Archive

Overview

The Revised Luyten Half-Second (LHS) Catalog contains refined coordinates and proper motion data for the high proper motion (HPM) stars listed in the Original Luyten Half-Second (LHS) catalog. The positional uncertainty in the Original LHS catalog is typically >10" and is often >30". The authors of the Revised LHS Catalog used the digital scans of the Palomar Observatory Sky Survey (POSS) I and POSS II plates to derive more accurate positions and proper motions for these objects. Out of the 4470 candidates in the LHS catalog, 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, which is a large improvement over the original data. Cross-correlation with the Tycho-2 and Hipparcos catalogs yielded 819 candidates (with red magnitude m_R <~12. For these brighter sources, the position and proper motion data were replaced with the more accurate Tycho/Hipparcos data. In total, there are revised proper motion measurements and coordinates for 4040 stars and revised coordinates for 4330 stars.

Catalog Bibcode

2002ApJS..141..187B

References

A Catalogue of Stars with Proper Motions Exceeding 0.5" Annually, also known
as the Luyten Half-Second (LHS) Catalog, 2nd Edition
     Luyten, W.J. 1979
     CDS Catalog I/87
     =1979lccs.book.....L

Revised Coordinates and Proper Motions of the Stars in the
Luyten Half-Second Catalogue
     Bakos G.A., Sahu K.C., Nemeth P.
    <Astrophys. J. Suppl. Ser. 141, 187 (2002)>
    =2002ApJS..141..187B

Provenance

This table was created by the HEASARC in October 2002 based on CDS Catalog I/279 (the 24-May-2002 version of the file catalog.dat).

Parameters

Name
The LHS Catalog designation for the star, i.e., the prefix LHS and the LHS Number.

LHS_Number
The LHS Catalog Number.

RA
The Right Ascension of the star for epoch 2000.0 and in the selected equinox. This parameter was given in epoch and equinox J2000 and with a precision of 0.01 seconds of time in the originating table. Bakos et al. calculated the equatorial coordinates for epoch and equinox 2000.0 using their astrometry and proper motion measurements. If none of the digital scans of POSS plates were available, or the difference between the epochs was not sufficient, proper motions from Luyten were accepted. If the star was not found, both coordinates and proper motions were taken from Luyten.

Dec
The Declination of the star for epoch 2000.0 and in the selected equinox. This parameter was given in epoch and equinox J2000 and with a precision of 0.1 arcseconds in the originating table. Bakos et al. calculated the equatorial coordinates for epoch and equinox 2000.0 using their astrometry and proper motion measurements. If none of the digital scans of POSS plates were available, or the difference between the epochs was not sufficient, proper motions from Luyten were accepted. If the star was not found, both coordinates and proper motions were taken from Luyten.

LII
The Galactic Longitude of the star.

BII
The Galactic Latitude of the star.

PM_Tot
The total proper motion of the star, in arcseconds per year. Bakos et al. calculated the equatorial coordinates for epoch and equinox 2000.0 using their astrometry and proper motion measurements. If none of the digital scans of POSS plates were available, or the difference between the epochs was not sufficient, proper motions from Luyten were accepted. If the star was not found, both coordinates and proper motions were taken from Luyten.

PM_Dir
The position angle of the proper motion vector,in degrees.

Position_Offset
The offset in arcseconds between the predicted J2000.0 positions of the star in the Original and Revised LHS Catalogs. A blank entry indicates that no new position is available and that the listed coordinates are taken from the Original LHS Catalog.

Comment_Flags
Flags indicating the following comments:

      1 = DSS I image has poor quality.
      2 = DSS II image has poor quality.
      B = position shift between the two frames is less than 5", proper motion
          data from LHS Catalogue is taken.
      C = refitting of position was done (due to saturation or merging).
      D = double star, or companion of a binary.
      H = coordinates, proper motion and magnitudes are from the Tycho-2
          Supplement-1 catalogue, i.e. from the Hipparcos catalogue (<I/239>).
      I = identification dubious.
      L = for some reason the new proper motion measurement is not accurate,
          Luyten's data are used. (The HEASARC changed the value of this flag
          from 'b' to 'L' to avoid confusion).
      M = merging.
      N = star was not found in manual search.
      P = POSS II DSS frame was not available.
      S = saturated on at least one of the frames.
      T = coordinates, proper motion and magnitudes are from the
          Tycho-2 catalogue (<I/259>).
      W = finder chart would have been needed for manual identification, but it
          was not available.
  

Luyten_RA_J2000
The Right Ascension (J2000 equator and epoch) of the star as listed in the Original (1979 version) LHS Catalog.

Luyten_Dec_J2000
The Declination (J2000 equator and epoch) of the star as listed in the Original (1979 version) LHS Catalog.

Luyten_PM_Tot
The total proper motion of the star, in arcseconds per year, as listed in the Original (1979 version) LHS Catalog.

Luyten_PM_Dir
The position angle of the proper motion of the star, in degrees, as listed in the Original (1979 version) LHS Catalog.

POSS_I_Epoch
The epoch of the POSS I plate in which the position of the measured.

POSS_II_Epoch
The epoch of the POSS II plate in which the position of the measured.

Red_Mag
The "Red" magnitude of the star. The red magnitude is taken from the Tycho Catalog V magnitude if the star was found in the Tycho-2 (Supplement-1) Catalog (CDS Cat. <I/259>, otherwise it is the Original LHS (CDS Cat. <I/87>) red magnitude.

Blue_Mag
The "Blue" Magnitude of the star. The blue magnitude is taken from the Tycho Catalog B magnitude if the star was found in the Tycho-2 (Supplement-1) Catalog (CDS Cat. <I/259>, otherwise it is the Original LHS (CDS Cat. <I/87>) photographic magnitude.

Alt_Name
The Tycho-2 or Hipparcos Catalog name of the star.

Class
The HEASARC Browse object classification: all objects in this table have been given the generic class of star.


Contact Person

Questions regarding the REVISEDLHS database table can be addressed to the HEASARC User Hotline.

Page Author: Browse Software Development Team
Last Modified: 8-Nov-2004