We recently discovered an apparently new class of pulsating Extreme Horizontal Branch (EHB) star in ω Cen. Tightly clustered around ˜50,000 K, these H-rich sdO stars exhibit rapid, multi-periodic oscillations on a timescale of 100 s. While four such objects have been detected in ω Cen, no counterparts have yet been found among the field population

Stellar-mass black holes (BHs) are mostly found in X-ray transients, a subclass of X-ray binaries that exhibit violent outbursts. None of the 50 Galactic BHs known show eclipses, which is surprising for a random distribution of inclinations. Swift J1357.2-0933 is a very faint X-ray transient detected in 2011. On the basis of spectroscopic evidence

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