A total of over 210 hr of previously unpublished differential photoelectric photometry of 21 Com (HD 108945, HR4766), obtained in five years, were analysed to search for periodicities. Of these, the 88 hr obtained in 1983, 1985, 1986 and 1989 were searched for, and show no indications of short-period variability. In 1988, over 116 hr of

The new observational O/Fe vs Fe/H relationship in halo dwarfs is analyzed in terms of a model of chemical evolution for the solar neighborhood. The role of nucleosynthesis prescriptions for SN II and SN I (both Ia and Ib) is analyzed. It is shown that, by adopting iron yields for SN II according to the observations of SN 1987A and by assuming

Deep spectra of the planetary nebula IC 418 were obtained in the wavelength range 4190-5850 A. The data made it possible to map an extended halo about the source, evaluate the variation in halo intensity with radius, and model the results in terms of a radially symmetric dust scatter envelope. It is suggested that the nebula is in a relatively

IAUC 5077 available at Central Bureau for Astronomical Telegrams. IAUC 5077 available at Central Bureau for Astronomical Telegrams.

IAUC 5079 available at Central Bureau for Astronomical Telegrams.

IAUC 5078 available at Central Bureau for Astronomical Telegrams.