I/279               Revised Luyten Half-Second Catalogue     (Bakos+ 2002)
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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
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ADC_Keywords: Positional data ; Proper motions ; Colors

Keywords: astronomical data bases: high proper motion - catalogues


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,
    which is a large improvement over the original data. Cross-correlation
    with the Tycho-2 and Hipparcos catalogues yielded 819 candidates (with
    mR<~12). For these brighter sources, the position and proper motion
    data were 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. In the printed
    version of the paper, we present the updated coordinates and proper
    motion information on 528 sources which represent the high proper
    motion subset (µ>1"/yr) of the LHS catalogue. The electronic
    version contains the updated information on all the 4470 stars in the
    LHS catalogue.

File Summary:

       FileName      Lrecl  Records   Explanations

ReadMe            80        .   This file
catalog.dat      133     4470   Revised Positions and Proper Motions for LHS stars


See also:
         I/87  : LHS Catalogue, 2nd Edition (Luyten 1979)
         I/239 : The Hipparcos and Tycho Catalogues (ESA 1997)
         I/259 : The Tycho-2 Catalogue (Hog+ 2000)
         I/269 : CCDM, Components of Double and Multiple stars (Dommanget+ 2002)
 J/AJ/124/1190 : Northern high proper motion stars in DSS (Lepine+, 2002)


Byte-by-byte Description of file:  catalog.dat

   Bytes Format Units     Label   Explanations

   1-  5  A5    ---       LHS     The Luyten Half-Second (LHS, Cat. I/87) number
   7-  8  I2    h         RAh     Hour of Right Ascension (J2000) (1)
  10- 11  I2    min       RAm     Minute of Right Ascension (J2000) (1)
  13- 17  F5.2  s         RAs     Second of Right Ascension (J2000) (1)
      19  A1    ---       DE-     Sign of the Declination (J2000) (1)
  20- 21  I2    deg       DEd     Degree of Declination (J2000) (1)
  23- 24  I2    arcmin    DEm     Arcminute of Declination (J2000) (1)
  26- 29  F4.1  arcsec    DEs     Arcsecond of Declination (J2000) (1)
  31- 36  F6.2  arcsec/yr pm      Proper motion
  38- 43  F6.2  deg       pmPA    Position angle of proper motion
  45- 49  F5.1  arcsec    Dist    ? Distance between predicted J2000.0 position
                                    of LHS and our measurements (2)
  51- 56  A6    ---       Com     Comments (3)
  58- 59  I2    h         RALh    Luyten's Hour of Right Ascension (J2000)
  61- 62  I2    min       RALm    Luyten's Minute of Right Ascension (J2000)
  64- 65  I2    s         RALs    Luyten's Second of Right Ascension (J2000)
      67  A1    ---       DEL-    Luyten's Sign of the Declination (J2000)
  68- 69  I2    deg       DELd    Luyten's Degree of Declination (J2000)
  71- 72  I2    arcmin    DELm    Luyten's Arcminute of Declination (J2000)
  74- 75  I2    arcsec    DELs    Luyten's Arcsecond of Declination (J2000)
  77- 82  F6.3  arcsec/yr muL     Luyten's original proper motion
  84- 88  F5.1  deg       PAL     ? Luyten's original position angle
  90- 99  F10.5 yr        POSSI   ? The POSS I epoch
 101-110  F10.5 yr        POSSII  ? The POSS II epoch
 112-115  F4.1  mag       Rmag    ? The "red" magnitude (4)
 117-120  F4.1  mag       Bmag    ? The "blue" magnitude (4)
 122-133  A12   ---       ID      The Tycho-2 (<I/259>) or Hipparcos (<I/239>)
                                  identification (5)

Note (1): Equatorial coordinates for epoch and equinox 2000.0 using our
    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 star was not found, both coordinates and proper motions were taken
    from Luyten.
Note (2): blank entries indicate coordinates of the LHS Catalogue
    were accepted.
Note (3): 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.
    H = coordinates, proper motion and magnitudes are from the Tycho-2
        Supplement-1 catalogue, i.e. from the Hipparcos catalogue (I/239).
    N = star was not found in manual search.
    P = POSS II DSS frame was not available.
    W = finder chart would have been needed for manual identification, but was
        not available.
    T = coordinates, proper motion and magnitudes are from the
        Tycho-2 catalogue (I/259).
    b = for some reason our proper motion measurement is not accurate,
        Luyten's data are used.
    c = refitting of position was done (due to saturation or merging).
    d = double star, or companion of a binary.
    m = merging.
    i = identification dubious.
    s = saturated on at least one of the frames.
Note (4): The red and blue magnitudes are Tycho, Cat. I/239 (Hipparcos),
    V and B if star was found in the Tycho-2, Cat. I/259, (Supplement-1)
    catalogue, otherwise LHS (I/87) red and photographic magnitudes.
Note (5): Identification of Tycho-2 (I/259) catalogue is of the format
    TYC1-TYC2-TYC3, while Hipparcos (I/239) is the single Hipparcos
    number followed by the CCDM component identifier (Dommanget & Nys,
    1994, See Cat. I/269).


Acknowledgements:
   Kailash C. SAHU, Space Telescope Science Institute, Baltimore, MD
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(End)                                   Francois Ochsenbein [CDS]    24-May-2002