J/AJ/113/806            M-Subdwarfs             (Gizis 1997)
================================================================================
M-Subdwarfs: Spectroscopic Classification and the Metallicity Scale
     Gizis J.E.
    <Astron. J., 113, 806 (1997)>
    =1997AJ....113..806G
================================================================================
ADC_Keywords: Stars, M-type; Spectroscopy; Radial velocities;
              Stars, population II; Stars, subdwarf; Photometry

Description:
   We present a spectroscopic classification system for M-dwarfs and
   M-subdwarfs based on quantitative measures of TiO and CaH features
   in the region 6200 - 7400 Angstroms.  Our sample of cool stars covers
   the range from solar metallicity stars to the most extreme subdwarfs
   known. Using synthetic spectra computed by Allard and Hauschildt (1995),
   we derive metallicities for the stars.  Stars are classified
   as dwarfs (M V), subdwarfs (sdM), or extreme subdwarfs (esdM).
   These classifications correspond to [m/H] = 0.0, -1.2, and
   -2.0 respectively. Our metallicity scale agrees with theoretical HR
   diagrams and HST globular cluster measurements.  We discuss some nearby
   subdwarfs of particular interest in light of our metallicity scale.
   We include photometry compiled from the literature.

File Summary:

       FileName      Lrecl  Records   Explanations

ReadMe            80        .   This file
table2.dat        65       79   Spectroscopic observations (table 2)
table4.dat        70       91   Photometry                 (table 4)


See also:
    III/198 : PMSU (Palomar/MSU nearby star spectroscopic survey; Hawley+ 1997)


Byte-by-byte Description of file: table2.dat

   Bytes Format  Units   Label     Explanations

   2-  6  A5     ---     LHS      *Number in LHS catalog
   8- 21  A14    ---     Name     *Other name
  23- 27  F5.3   ---     TiO5      TiO5 index: F(7126-7135)/F(7042-7046)
  29- 33  F5.3   ---     CaH1      CaH1 index: F(6380-6390)/F
                                     (6345-6355,6410-6420))
  35- 39  F5.3   ---     CaH2      CaH2 index: F(6814-6846)/F(7042-7046)
  41- 45  F5.3   ---     CaH3      CaH3 index: F(6960-6990)/F(7042-7046)
  47- 52  F6.1   km/s    RV       *Radial Velocity
  54- 60  A7     ---     Sp        Spectral type
  62- 65  A4     ---     code     *Telescope code

Note on LHS, Name:
   Gl   - Gliese (1969, Veroff. Astr. Rechen-Instituts, Heidelberg, Nr. 22)
   GJ   - Gliese & Jahreiss                                =1979A&AS...38..423G
   Wo   - Woolley et al (1970, R. Obs. Ann., No. 5)        =Cat. V/32
   LHS  - Luyten Half-Second Catalogue                     =Cat. I/87
   LP   - Luyten Palomar proper-motion catalogue
   G    - Giclas et al (1971, Lowell Proper Motion Survey) =Cat. I/79
   Sm   - Smethers, see Reid (1982, MNRAS, 201, 51)
   TVLM - Tinney Very Low Mass, see Tinney et al. (1995AJ....110.3014T)
Note on RV:
   Radial velocity for LHS 2715 has been deleted; it was incorrect.
Note on code:
   Source of spectroscopic data:
      60  - Palomar 60-in. telescope
     100  - Las Campanas 100-in. telescope
     200  - Hale 200-in. (Palomar) telescope
     200a - Hale 200-in. (Palomar) telescope, August 1995 setup
     RHG  - Taken from Reid et al. (1995AJ....110.1838R)


Byte-by-byte Description of file: table4.dat

   Bytes Format  Units  Label    Explanations

   2-  6  A5     ---    LHS      Number in LHS catalog
   8- 12  F5.2   mag    V        Apparent V magnitude
  14- 17  F4.2   mag    B-V      ? B-V color
  19- 22  F4.2   mag    V-R      ? V-R (Cousins) color
  24- 27  F4.2   mag    R-I      ? R-I (Cousins) color
  29- 32  F4.2   mag    V-I      ? V-I (Cousins) color
  34- 39  F6.4   arcsec Plx      ? Trigonometric parallax
  41- 46  F6.4   arcsec e_Plx    ? Uncertainty {sigma} of parallax
  49- 53  F5.2   mag    DeltaLK *? Lutz-Kelker correction
  55- 59  F5.2   mag    MV      *? Absolute V magnitude
  61- 70  A10    ---    ref     *Source of parallax and photometry

Note on DeltaLK:
   Blank in Lutz-Keller correction indicates a null.
   -9.99 indicates that the Lutz-Kelker correction is undefined but < -0.80,
     as symbolized by "L" in the original paper.
Note on MV:
   Absolute magnitude of LHS 2497 includes 0.75 magnitude correction
     for unresolved companion
Note on ref:
   Dr. Jahreiss has brought to our attention the fact that DF89's photometry
     of LHS 272 is inconsistent with the results of Doyle and Butler
     (1990A&A...235..335D), Eggen, and Weis.  Our comparison of the spectrum
     to other subdwarfs suggests that DF89's photometry is too red; thus,
     we adopt the other photometry for this electronic version.

   References for the trigonometric parallaxes and photometry are:
   B    - Bessell             (1990A&AS...83..357B)
   CNS3 - Gliese and Jahreiss (1991, ADC Cat. 5070)
   DF89 - Dawson and Forbes   (1989PASP..101..614D)
   DF92 - Dawson and Forbes   (1992AJ....103.2063D)
   E79  - Eggen               (1979ApJS...39...89E)
   E87  - Eggen               (1987AJ.....93..379E)
   HD   - Harrington and Dahn (1980AJ.....85..454H)
   L    - Leggett             (1992ApJS...82..351L)
   M92  - Monet et al.        (1992AJ....103..638M)
   R    - Ryan                (1992AJ....104.1144R)
   RA   - Ruiz and Anguita    (1993AJ....105..614R)
   S    - SIMBAD
   T    - Tinney et al.       (1995AJ....110.3014T)
   W84  - Weis                (1984ApJS...55..289W)
   W88  - Weis                (1988AJ.....96.1710W)
   W91  - Weis                (1991AJ....101.1882W)
   WU   - Weis and Upgren     (1982PASP...94..821W)
   Y    - Van Altena et al.   (1991)


References:
   Bessell, 1990, Astron. Astrophys. Suppl. 83, 357. (1990A&AS...83..357B)
   Dawson & Forbes, 1992, Astron. J. 103, 2063. (1992AJ....103.2063D)
   Dawson & Forbes, 1989, Pub. Astron. Soc. Pac. 101, 614. (1989PASP..101..614D)
   Doyle and Butler, 1990, Astron. Astrophys. 235, 335. (1990A&A...235..335D)
   Eggen, 1979, Astrophys. J. Suppl. 39, 89. (1979ApJS...39...89E)
   Eggen, 1987, Astron. J. 92, 379. (1987AJ.....93..379E)
   Giclas et al., 1971, Lowell Proper Motion Survey (Flagstaff, AZ:
     Lowell Obs.). ADC Cat. 1079.
   Gliese & Jahreiss, 1991, Preliminary Version of the Third Catalog of
     Nearby Stars (CNS3), ADC Cat. 5070
   Gliese, 1969, Veroff. Astr. Rechen-Instituts, Heidelberg, Nr. 22.
   Gliese & Jahreiss, 1979, Astron. Astrophys. Suppl., 38, 423.
     (1979A&AS...38..423G)
   Gizis, 1997, Astron. J., 113, 806 (1997AJ....113..806G)
   Harrington & Dahn, 1980, Astron. J. 85, 454. (1980AJ.....85..454H)
   Leggett, 1992, Astrophys. J. Suppl. 82, 351. (1992ApJS...82..351L)
   Luyten, 1979, Catalogue of stars with proper motions exceeding 0.5
     arcsec annually (Minneapolis: U Minnesota). ADC Cat. 1098
   Monet et al., 1992, Astron. J. 103, 638. (1992AJ....103..638M)
   Reid, 1982, Mon. Not. R. Astron. Soc. 201, 51. (1982MNRAS.201...51R)
   Reid et al., 1995, Astron. J. 110, 1838. (1995AJ....110.1838R)
   Ruiz & Anguita, 1993, Astron. J. 105, 614. (1993AJ....105..614R)
   Ryan, 1992, Astron. J. 104, 1144. (1992AJ....104.1144R)
   Tinney et al., 1995, Astron. J. 110, 3014. (1995AJ....110.3014T)
   Van Altena et al., 1991, General Catalog of Trigonometric Stellar
     Parallaxes: Preliminary Version. (See ADC Cat. 1238)
   Weiss, 1984, Astrophys. J. Suppl. 55, 289. (1984ApJS...55..289W)
   Weiss, 1988, Astron. J. 96, 171. (1988AJ.....96.1710W)
   Weiss, 1991, Astron. J. 101, 1882. (1991AJ....101.1882W)
   Weis & Upgren, 1982, Pub. Astron. Soc. Pac. 94, 821. (1982PASP...94..821W)
   Woolley et al., 1970, R. Obs. Ann., No. 5. ADC Cat. 5032.
================================================================================
(End)                                     John Gizis [U.Mass]        15-Dec-1997