Recently, Narayan, Garcia and McClintock showed that there is a difference in the quiescent luminosities of black hole and neutron star x-ray nova: when the quiescent, Eddington scaled luminosities are compared, every black hole x-ray nova (BHXN) is fainter than every the neutron star x-ray nova (NSXN). To this earlier work we add three more BHXN

Beryllium and oxygen abundances have been derived in a sample of F-type field stars for which lithium abundances had been measured previously, with the aim of obtaining observational constraints to discriminate between the different mixing mechanisms proposed. Mixing associated with the transport of angular momentum in the stellar interior and

The aim of the present work is the detection of solar g-modes, making use of their spatial and temporal properties, by means of a new observational strategy. The basic data, gathered at the Observatorio del Teide in 1993, consists on daily solar velocity measurements taken continuous and sequentially at six different and symmetric positions on the

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An inversion technique has been developed to recover LTE one-dimensional model photospheres for late-type stars from very high-resolution high signal-to-noise stellar line profiles. It is successfully applied to the Sun using a set of unblended Ti 1, Ca 1, Cr 1 and Fe 1 lines with accurate transition probabilities. Temperature stratification