A survey of 380 sq. deg. of the sky with the 1m Schmidt telescope at the Observatorio Nacional de Llano del Halo and the QUEST camera has found 498 RR Lyrae variables lying from 4 to 60 kpc from the Sun. We describe the halo substructure revealed by these data and the results of measuring some of the stars' radial velocities and metal abundances.

The second Hispano-Argentinian Meridian Catalogue (HAMC2) contains more than 12.500.000 positions and magnitudes of stars brighter than V=16.5 and with declinations between -30° and 0°. It has been computed from the CCD observations of the San Fernando Automatic Meridian Circle (CMASF) installed at present at the Carlos U. Cesco Observatory (CUC)

We have run high resolution N-body models simulating the encounter of a dwarf galaxy with a bright elliptical galaxy. The dwarf absorbs orbital angular momentum and shows counter-rotating features in the external regions of the galaxy. To explain the core-envelope kinematic decoupling observed in some dwarf galaxies in high-density environments

The star HD 144548 (=HIP 78977; TYP 6212-1273-1) has been known as a detached eclipsing binary and a bona-fide member of the Upper Scorpius OB association. Continuous photometry from the K2 mission on Campaign Two has revealed the presence of additional eclipses due to the presence of a third star in the system. These are explained by a system

We report the detection of transits by the 3.1 M_Jup companion to the V=8.17 G0V star HD 17156. The transit was observed by three independant observers on Sep. 9/10, 2007 (two in central Italy and one in the Canary Islands), who obtained detections at confidence levels of 3.0σ, 5.3σ, and 7.9σ, respectively. The observations were carried out under

We present high-resolution spectroscopy of HD 306414, optical counterpart to the hard X-ray transient IGR J11215-5952, an object belonging to the class of Supergiant Fast X-ray Transients. We derive a spectral type B0.5 Ia for HD 306414 and determine its stellar parameters from an atmosphere model fit to the spectrum. Our data, taken around the