A search for stellar variability based on time resolved CCD observations for the open cluster NGC 6802, was conducted in June 1990 at the 2.5 Isaac Newton Telescope (INT), at the Observatorio del Roque de los Muchachos (ORM), La Palma, Canary Islands, Spain. The main goal of this kind of observations was the detection of p-modes in solar-like stars

We have derived the oxygen abundances of 50 F-type main-sequence stars, belonging to the Hyades open cluster, the Ursa Major group, and the field, using an NLTE analysis of the infrared triplet lines of O I at 7771-7775 AA. The stars of the middle F-range have previously been shown to exhibit a marked reduction in lithium abundance compared with

From high-resolution spectroscopy in the Li I λ67O.8 nm region of the double-lined detached eclipsing binary system EK Cepheid, we find a surface lithium abundance in the low-mass (1.12 M0) secondary of log N(Li)NLTE = 3.l±0.3, i.e., close to the present "cosmic" Li abundance. The abundances of Ca, Si and Fe, inferred from metallic lines in the

We present a procedure for associating statistical significances with the results of the likelihood analysis of the experiment of Davies et al. (1987) for the detection cosmic background radiation temperature fluctuations. This procedure allows us to say that a Chi-squared test which accounts for the correlation of the measurements is to be

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This paper reports the discovery of a second type Ia supernova (SN 1992ac) in MCG 10-24-007 (IRAS 16362 + 5815), the parent galaxy of another type Ia supernova (SN 1992R). As seen from here, these two events must have occurred nearly simultaneously (separated by less than two months) as indicated by the appearance of their spectra. To our knowledge