In order to develop a reliable method of distance determination of W UMa-type stars, a catalogue of light curve solutions of 159 systems has been compiled. The rate of transferred luminosity from the primary star to the secondary star was determined based on the catalogue data. This quantity has an important role in the distance determination. The

We present a deep multicolor NIR survey that we are currently undertaking at the Instituto de Astrofísica de Canarias (Spain). The aim of the survey is obtain deep star counts in selected areas distributed along the Galactic plane to analyze the large scale structure of the Milky Way and the galactic components, in particular the Galactic bar. We

Jovian X-rays can be broadly classified into two categories: (1) "auroral" emission, which is confined to high-latitudes ( ˜>60° ) at both polar regions, and (2) "dayglow" emission, which originates from the sunlit low-latitude ( ˜

We present astrometric monitoring data of the binary brown dwarf DENIS-P J1228.2-1547. The data have been obtained with the Hubble Space Telescope over a time span of 5.5 yr, and confirm that DENIS-P J1228.2-1547 is indeed a common proper motion, i.e., physical, binary. The data cover about 1/8th of the binary orbit, indicating an orbital period of

In this paper we present beryllium (Be) abundances in a large sample of 41 extra-solar planet host stars, and for 29 stars without any known planetary-mass companion, spanning a large range of effective temperatures. The Be abundances were derived through spectral synthesis done in standard Local Thermodynamic Equilibrium, using spectra obtained

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