The distribution of stars in the Hertzsprung-Russell diagram narrates their evolutionary history and directly assesses their properties. Placing stars in this diagram however requires the knowledge of their distances and interstellar extinctions, which are often poorly known for Galactic stars. The spectroscopic Hertzsprung-Russell diagram (sHRD) tells similar evolutionary tales, but is independent of distance and extinction measurements. Based on spectroscopically derived effective temperatures and gravities of almost 600 stars, we derive for the first time the observational distribution of

Stellar-mass black holes have all been discovered through X-ray emission, which arises from the accretion of gas from their binary companions (this gas is either stripped from low-mass stars or supplied as winds from massive ones). Binary evolution models also predict the existence of black holes accreting from the equatorial envelope of rapidly spinning Be-type stars (stars of the Be type are hot blue irregular variables showing characteristic spectral emission lines of hydrogen).  Of the ~80 Be X-ray binaries known in the Galaxy, however, only pulsating neutron stars have been found as

Happy New Year 2014 from the Instituto de Astrofísica de Canarias (IAC)

With the Canaricam instrument on the Gran Telescopio CANARIAS (GTC), a team of researchers known as ‘Los Piratas’ have caught a system of two galaxies fused together in collision, feeding two black holes at their centres

Astronomers at the IAC have discovered complex patterns of resonances in the discs of spiral galaxies not previously described by theories. Using the GHaFaS 2dimensional spectrometer they have measured the velocities of the density waves in the discs of over a hundred galaxies Within the discs of spiral galaxies there are waves which propagate concentrically in the form of spirals. This is somewhat similar to the waves on the surface of a lake, or the standing waves on the strings of a violin, or on the surface of a drum, to use a musical metaphor. These are the so-called “density waves”

NASA: The Geminids from the Canaries, astronomical image of the day We receive a message from an asteroid in the guise of a meteor shower