We present new UBVI CCD observations of the old LMC globular cluster RETICULUM. These data allowed us to re-determine periods and light curves and to identify 4 double mode RR Lyrae stars. A comparison with the theoretical instability strip in the M_V-log P plane shows good agreement between theory and observations when an apparent distance modulus

We investigate the improved detection of extrasolar planets around eclipsing binaries using eclipse minima timing and extrasolar moons around transiting planets using transit timing offered by the upcoming COROT (ESA, 2005), Kepler (NASA, 2007), and Eddington (ESA 2008) spacecraft missions. Hundreds of circum-binary planets should be discovered and

Using the Very Large Array (VLA) and the Very Long Baseline Array (VLBA), we have observed water maser emission in the proto-planetary nebula candidate IRAS 19134+2131, in which the water maser spectrum has two groups of emission features separated in radial velocity by ˜100 km s-1. The blue-shifted and red-shifted clusters of maser features are

We determine the Fe abundances for several blue compact and emission-line galaxies. The O/Fe abundance ratios are found to increase with the metallicity of the galaxy, and to decrease with its degree of ionization. These correlations are interpreted as reflecting a decrease for lower metallicities of the depletion of Fe atoms on to dust grains

RX J1211+2242 is an optically faint (B~=19.2mag) but X-ray bright (f2-10keV=5×10-12ergscm-2s-1) active galactic nucleus (AGN) that has been shown to be a BL Lac object at redshift z=0.455. The ROSAT X-ray, Calar Alto optical, and NRAO VLA Sky Survey (NVSS) radio data suggest that the peak of the synchrotron emission of this object is at energies as

We present the results of an analysis of our infrared light curves of the Algol-type binary AI Draconis in the J, H and K bands, and of published light curves in the B, V and Strömgren uvby bands, together with spectra obtained by us. The analysis of the light curves was carried out using a code based on ATLAS model atmospheres and Roche geometry