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II/40       Hydrogen-Line Absorption in Early-Type Stars (Bappu+ 1962)
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Photoelectric Measures of Hydrogen-Line Absorption in Early-Type Stars
    Bappu M.K.V., Chandra S., Sanwal N.B., Sinvhal S.D.
    <Mon. Not. R. Astron. Soc., 123, 521 (1962)>
    =1962MNRAS.123..521B
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ADC_Keywords: Photometry, hydrogen-line; Stars, early-type

Abstract:
   Photoelectric determinations of H-{gamma} absorption line intensity have 
   been made of stars in selected clusters and associations as well as in the 
   general galactic field. Interference filters having a width at half
   intensity of 45 A were used to isolate spectral regions centered on 4280 A,
   H-{gamma} and 4410 A. The {Gamma} indices derived, which represent a measure
   of H-{gamma} absorption, can be used in conjunction with unreddened values
   of either (U-B) or (B-V) for spectral and luminosity class determinations
   of stars in the spectral range O6 to A0.

File Summary:
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 FileName     Lrecl  Records   Explanations
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ReadMe           80        .   This file
data.dat         25      177   Data
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Byte-by-byte Description of file: data.dat
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   Bytes Format  Units   Label    Explanations
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   1-  6  I6     ---     HD       ? Henry Draper number
   8- 11  F4.2   mag     V0       ? V0 magnitude
  13- 17  F5.2   mag     (U-B)0   ? (U_B)0 color index
  19- 21  I3     ---     Gamma   *Gamma index
  23- 25  I3     ---     ID       Running number 
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Note on Gamma:
   {Gamma} * 10^-3 = -2.5 * log[(L*S)^(1/2)/{gamma}]
     where L, S and {gamma} indicate the respective deflections through the 
     filters that isolate respectively the continuum on the long and short 
     sides and the radiation at the position of the H{gamma} line.

References:
   Bappu M.K.V., Chandra S., Sanwal N.B., and Sinvhal S.D. 1962, Mon. Not. R. 
     Astron. Soc., 123, 521
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(End)                                  Julie Anne Watko [SSDOO/ADC]  19-DEC-1996