Entre los 400.000 millones de estrellas de La Vía Láctea se encuentra el Sol, cuyas características físicas hacen posible que albergue un sistema planetario, El Sistema Solar. Esta condición parece sufcientemente atractiva para justificar su estudio aunque, sin duda, existen otras razones que lo avalan. Por su proximidad a La Tierra, es la única

We have performed a uniform analysis of the power spectrum densities (PSDs) of 104 nearby (z ~= 2 × 10-4 Hz. Only KUG 1031+398 (RE J1034+396) shows evidence for quasi-periodic oscillations. The `fundamental plane' relating variability timescale, black hole mass, and luminosity is demonstrated using the new X-ray timing results presented here

Active galactic nuclei (AGN) are powered by energetic phenomena which cannot be attributed to stars. LINERs appears to be the low power end of the AGN sequence with the lowest Eddington ratios but hosting the most massive black holes (typically 109 M&sun;). Whereas variability is common for high Eddington ratio emitting sources, in the low

We present a detailed chemical abundance analysis of a sample of F- and G-type stars. We investigate the possibility that the presence of terrestrial planets could affect the volatile-to-refractory abundance ratios. Stars with and without planets exhibit very similar abundance behaviours, either for solar twins or even when considering the whole

We present the first large-scale stellar kinematic and line-strength maps for dwarf elliptical galaxies (nine in the Virgo cluster and three in the field environment) obtained with the SAURON (Spectrographic Areal Unit for Research on Optical Nebulae) integral-field unit. No two galaxies in our sample are alike: we see that the level of rotation is

Aims: Projected rotational velocities (vesini) have been estimated for 334 targets in the VLT-FLAMES Tarantula Survey that do not manifest significant radial velocity variations and are not supergiants. They have spectral types from approximately O9.5 to B3. The estimates have been analysed to infer the underlying rotational velocity distribution