Aims: With available Virtual Observatory tools, we looked for new M dwarfs in the solar neighbourhood and M giants with high tangential velocities. Methods: From an all-sky cross-match between the optical Tycho-2 and the near-infrared 2MASS catalogues, we selected objects with proper motions μ > 50 mas yr-1 and very red VT - Ks colours. For the

We identify HS 2325+8205 as an eclipsing, frequently outbursting, dwarf nova with an orbital period of Porb = 279.841731(5) minutes. Spectroscopic observations are used to derive the radial velocity curve of the secondary star from absorption features and also from the Hα emission lines, originating from the accretion disk, yielding Ksec = Kabs =

The first high-resolution (R˜ 50 000) optical spectrum of the B-type star, LS III +52°24, identified as the optical counterpart of the hot post-asymptotic giant branch (post-AGB) candidate IRAS 22023+5249 (I22023) is presented. We report the detailed identifications of the observed absorption and emission features in the full wavelength range (4290

In this paper, we study the heating of the magnetized solar chromosphere induced by the large fraction of neutral atoms present in this layer. The presence of neutrals, together with the decrease with height of the collisional coupling, leads to deviations from the classical magnetohydrodynamic behavior of the chromospheric plasma. A relative net

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We present the study of a large sample of early-type dwarf galaxies in the Coma cluster observed with DEIMOS on the Keck II to determine their internal velocity dispersion. We focus on a subsample of 41 member dwarf elliptical galaxies for which the velocity dispersion can be reliably measured, 26 of which were studied for the first time. The