II/40 Hydrogen-Line Absorption in Early-Type Stars (Bappu+ 1962) ================================================================================ Photoelectric Measures of Hydrogen-Line Absorption in Early-Type Stars Bappu M.K.V., Chandra S., Sanwal N.B., Sinvhal S.D. =1962MNRAS.123..521B ================================================================================ 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{AA} were used to isolate spectral regions centered on 4280{AA}, H-{gamma} and 4410{AA}. 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: -------------------------------------------------------------------------------- FileName Lrecl Records Explanations -------------------------------------------------------------------------------- ReadMe 80 . This file data.dat 79 177 {Gamma} values (from table II of paper) -------------------------------------------------------------------------------- Byte-by-byte Description of file (#): data.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 12 A12 --- Star Star identification (HD or cluster star number) 23- 25 I3 cmag V0 ? Dereddened V_0_ magnitude 32- 35 I4 cmag (U-B)0 ? Dereddened (U-B)_0_ color index 43- 45 I3 --- Gamma {Gamma} index (1) 77- 79 I3 --- ID [0/177] Running number -------------------------------------------------------------------------------- Note (1): {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. -------------------------------------------------------------------------------- History: * October 1972: keypunched at Institut d'Astronomie de Lausanne (Switzerland) * 19-Dec-1996: standarized by Julie Anne Watko [SSDOO/ADC] * 11-Jan-2017: star name completed for missing HD designations ================================================================================ (End) Julie Anne Watko [SSDOO/ADC] 19-Dec-1996