We have developed TGMETalpha in order to determine T[eff], logg, [Fe/H] and [alpha/Fe] for large samples of FGK stars observed at various spectral resolutions. Tests on several hundred echelle spectra of reference stars degraded at low resolution (R=1.000) have provided typical rms precisions of sigma_ T [eff]~150 K, sigma_logg~0.44, sigma_[Fe/H]~0

Table 23 (tables 2 & 3 of the paper) contains the derived stellar parameters, metallicities, and masses, for stars not known to harbor any planetary-mass companion. Table 4 contains the derived stellar parameters, metallicities, and masses, for extra-solar planet-host stars. (2 data files).

We present narrowband observations of the Hα emission in a sample of 31 satellites orbiting isolated giant spiral galaxies. The sample studied spans the range -19 mag

We have obtained projected rotation velocities (vrotsini) of a sample of 19 ultracool dwarfs with spectral types in the interval M6.5-T8 using high-resolution, near-infrared spectra obtained with NIRSPEC and the Keck II telescope. Among our targets there are two young brown dwarfs, two likely field stars, and 15 likely brown dwarfs (30-72 MJup) in

We present seeing measurements from Mt. Holomon (Chalkidiki, Greece), a possible site for the establishment of a new University of Thessaloniki Observatory, using the Hartman - DIMM method. After two years of systematic observations we present the first robust results and give a first evaluation of the astronomical seeing characteristics, which are

We study the broadband polarization of hydrogen lines produced by scattering of radiation, in the presence of isotropic electric fields. In this paper, we focus on two distinct problems: (a) the possibility of detecting the presence of turbulent electric fields by polarimetric methods and (b) the influence of such fields on the polarization due to