III/166  A New Library of Optical Spectra (Silva + 1992)
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A New Library of Stellar Optical Spectra
  Silva D.R., Cornell M.E.
  <Astrophys. J. Suppl. 81, 865 (1992)>
  =1992ApJS...81..865S
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ADC_Keywords: Spectrophotometry ; Spectral types

Abstract:
    Silva and Cornell have compiled a new digital optical stellar spectra
    library, consisting of intensities at 5A intervals between 3510A and
    8930A for 72 different spectral types. These types range from O to M
    and luminosities range from I to V. Some weak-line and strong-line
    spectra are also included. The intensities are in ergs/A, normalized
    to 100 at 5450A.

Description:
    Newly acquired and previously published data have been combined to
    form a new digital optical library intended primarily for use in
    empirical population synthesis. Stellar data for a large number of
    individual stars were acquired during seven observing runs between
    December 1988 and May 1989. An effort was made to observe, primarily,
    stars with TZG parameters derived from stellar atmosphere models of
    high dispersion data. Observations of photometric calibration stars
    were made during each run, but absolute calibrations were not
    attempted.

    Composite spectra from different observations of each star were formed
    by multiplicatively scaling the individual sub-spectra and averaging.
    The resultant composite spectra were normalized to 100 at 5450A. Next,
    the effects of interstellar reddening were removed. Intensities in the
    spectral regions most affected by telluric absorption were set to
    zero. Finally, stars with similar TZG parameters and similar overall
    spectral characteristics were averaged to form the individual spectra
    in the library, also normalized to 100 at 5450A. Table 1 lists the
    individual types averaged to form each of the 72 entries in the
    catalog. The prefixes R and W refer to strong- and weak-line stars,
    respectively.

    The list of the observed stars (Table 2 of the paper), and the
    synthesized UBV colors (Tables 3 and 4 of the paper) were added to the
    electronic catalog in 1999.

File Summary:
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 FileName     Lrecl   Records    Explanations
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ReadMe           80         .    This file
stars.dat        91       151   *List of stars observed (Table 2)
spectra.dat      54        72   *Composite library spectra: Synthesized versus
                                    Catalog UBV colours (Tables 3 and 4)
sp/*             .         72    The synthetic spectra (1 file per spectrum)
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Note on stars.dat, spectra.dat:
  Two stars quoted in Table 3 of the paper are not in file stars.dat:
     242935  (in spectral class O7B0V)
     g137-69 (in wG8-K0)
  Three stars in file stars.dat are not used in spectra.dat:
     236894  (O8V)
     115043  (G1Va)
     s84091  (K0V)
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Byte-by-byte Description of file: stars.dat
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   Bytes Format Units   Label     Explanations
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   1-  2  I2    ---     SpNo      [1,72]? Spectrum number
   4-  5  I2    h       RAh      *Right Ascension J2000 (hours)
   7-  8  I2    min     RAm      *Right Ascension J2000 (minutes)
  10- 13  F4.1  s       RAs      *Right Ascension J2000 (seconds)
      15  A1    ---     DE-      *Declination J2000 (sign)
  16- 17  I2    deg     DEd      *Declination J2000 (degrees)
  19- 20  I2    arcmin  DEm      *Declination J2000 (minutes)
  22- 23  I2    arcsec  DEs      *Declination J2000 (seconds)
  25- 30  I6    ---     HD        ? HD designation of the star
  33- 39  A7    ---     Other    *Other designation
  42- 50  A9    ---     Sp       *MK Spectral class
  52- 61  A10   ---     Obs      *[AC-K.] Observations flags
  64- 68  I5    K       Teff      Effective temperature
      71  I1    ---     L         Assigned luminosity class
  73- 74  I2    ---     M        *[-1,1] Assigned metallicity class
  76- 80  F5.2  [Sun]   [Fe/H]    Metallicity index
  83- 86  F4.2  mag     E(B-V)    Colour excess
  88- 91  A4    ---     Ref      *Reference
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Note on RAh, RAm, RAs, DE-, DEd, DEm, DEs:
     position from SIMBAD data-base
Note on Other: the designation starts by "s" for SAO (Cat. <I/131>)
     designations, or by "g" for Giclas et al. Lowell Proper Motion stars.
Note on Sp: Spectral class from original reference. Stars from reference
     L (1988AJ.....95.1843L) and marked V* are most likely dwarfs, but could
     be some other luminosity class.
Note on Obs: Observation codes are:
     A = MDM  2.4m 1988Jan, MkIII spectrograph, G4 grism
     C = MDM  2.4m 1988Feb, MkIII spectrograph, G4 grism
     D = SOKP 2.3m 1988Mar, B&C   spectrograph
     E = SOKP 2.3m 1988May, B&C   spectrograph
     F = MDM  2.4m 1988Nov, MkIII spectrograph, G2 grism
     G = MDM  2.4m 1988Nov, MkIII spectrograph, G4 grism
     H = MDM  2.4m 1989Feb, MkIII spectrograph, G4 grism
     I = MDM  2.4m 1989Feb, MkIII spectrograph, G2 grism
     J = MDM  2.4m 1989May, MkIII spectrograph, G4 grism
     K = MDM  2.4m 1989May, MkIII spectrograph, G2 grism
     where MDM  designates Michigan-Dartmouth-MIT, spectral regime:
                G2 = 675-925nm, G4 = 436-710nm
       and SOKP designates Stewart Obs. Kitt Peak, spectral regime 337-470nm
Note on M: classes are:
     1 = metal-rich,    0.15 <  [Fe/H]
     0 = metal normal, -0.20 <= [Fe/H] <= 0.15
    -1 = metal poor,            [Fe/H] < -0.20
Note on Ref: codes are:
    FEH  = Cayrel de Strobel, 1985A&AS...59..145C
    FFBG = Faber et al., 1985ApJS...57..711F
    JHC  = Jacoby et al., 1984ApJS...56..257J
    L    = Laird et al., 1988AJ.....95.1843L
    LB   = Luck & Bond, 1985ApJ...292..559L
    M83  = Keenan, 1983BICDS..24...19K
    TTCB = Turnshek et al., 1985,
           "An atlas of Digital Spectra of Cool stars",
           Tucson: Western Research Company
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Byte-by-byte Description of file: spectra.dat
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   Bytes Format Units   Label     Explanations
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   1-  2  I2    ---     SpNo      [1,72] Spectrum number
   5- 13  A9    ---     Sp       *Spectral class designation
  14- 18  F5.2  mag     (U-V)s    ? Synthesized U-V colour
  20- 24  F5.2  mag     (B-V)s    ? Synthesized B-V colour
  26- 30  F5.2  mag     (U-V)c    ? Catalog U-V colour
  32- 36  F5.2  mag     (B-V)c    ? Catalog B-V colour
  38- 42  F5.2  mag     (U-V)r    ? Residuals U-V colour
  44- 48  F5.2  mag     (B-V)r    ? Residuals B-V colour
  50- 54  A5    ---     Ref       Reference
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Note on Sp:
  this composite spectral class is used to designate the file
  with spectrophotometric data (in "sp" subdirectory)
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Structure of files: sp/*.dat
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   Bytes    Format  Units   Label   Explanations
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   1-  5     F5.1   nm      wavel   central wavelength for each pixel
   6- 13     F8.3   ---     I       normalized intensity to 100 at 545.0 nm
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Verification and Modifications:
  * May 1992: files received and documented by Nancy G. Roman at
    NASA/SSDOO/ADC.
  * 25-Apr-1995, N.P.M. Kuin (NASA/SSDOO/ADC):
    The data were received by the ADC as one large file. The individual
    spectra were extracted and put in individual files. A wavelength scale
    was appended explicitly to each file.
  * 15-Sep-1999, Francois Ochsenbein, James Marcout (CDS):
    files spectra.dat and stars.dat were added from tables of paper.
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(End)               Francois Ochsenbein, James Marcout [CDS]         15-Sep-1999
