On the helium abundance in globular cluster stars.

The spectra of six globular cluster stars have been obtained using a 500-channel photon counter on a 6-m telescope. The 4026- and 4471-A He I lines are found to occur in the spectra of the program stars that are located above the horizontal branch in the color-magnitude diagram (M3 II-57 and M13 B29), as well as in the horizontal branch star M13 II-25. In M13 AJ-110, only the intensity at 4026 A is estimated since the spectrum is limited to 3900-4400 A. The equivalent width of the 4026-A line is 1.8 and 1.3 A in AJ-110 and II-25, respectively. The absence of the He lines from the spectra of two stars in M92 (III-27 and II-40) does not necessarily mean that their atmospheres are helium-poor, since in this case the log g values of the 4026-A He I equivalent widths, even for a normal He abundance, should be no more than 0.5 A, the line detection limit of the spectrograms obtained in this study.