Massive Unseen Companions to Hot Faint Underluminous Stars from SDSS (MUCHFUSS)—Status report Available to Purchase

The project Massive Unseen Companions to Hot Faint Underluminous Stars from SDSS (MUCHFUSS) aims at finding hot subdwarf stars with massive compact companions like massive white dwarfs $(M>1.0 M⊙),$ neutron stars or stellar mass black holes. The existence of such systems is predicted by binary evolution theory and recent discoveries indicate that they exist in our Galaxy. We classified about 1500 hot subdwarf stars from the Sloan Digital Sky Survey (SDSS) by colour selection and visual inspection of their spectra. Stars with high velocities have been reobserved and individual SDSS spectra have been analysed. In total ≃170 radial velocity variable subdwarfs have been discovered and ≃80 of them have been selected as good candidates for follow‐up time resolved spectroscopy to derive their orbital parameters. Up to now we found seven close binary sdBs with short orbital periods ranging from ≃0.21 d to 1.5 d. In our photometric follow‐up campaign we discovered two eclipsing binaries with companions, that are more most likely substellar.