The abundance ratio of D:H in the interstellar medium can be derived either more directly from the UV absorption measurements of HD and H2 in the spectra of early-type stars, or less directly from millimeter-wave emission in the rotational lines of a variety of molecules. The latter method is applicable over a much larger portion of the galaxy, but

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An identification list is presented for the visible spectra of Pi Cet (B7 V), 36 Lyn (B8 IIIp), and 134 Tau (B9 IV). Equivalent widths are measured on medium dispersion plates of 7.0 and 12.4 A/mm, and the photographic plates are digitized using a PDS 1010A microdensiometer. The effective temperature and gravity of the three stars are estimated

The joint consideration of theoretical and observational arguments is used to conclude that two different spot populations co-exist in the Sun.

The discrete structure in the 5 min velocity oscillations of the solar surface has been confirmed by a re-analysis of data obtained between 1976 and 1979, and in addition a preliminary analysis of 1980 data show excellent consistency of the determined frequencies over the five year period. It is further shown that atmospheric transparency, as