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We started a new project which aims to find compact hot subdwarf binaries at low Galactic latitudes. Targets are selected from several photometric surveys and a spectroscopic follow-up campaign to find radial velocity variations on timescales as short as tens of minutes has been started. Once radial variations are detected phase-resolved spectroscopy is obtained to measure the radial velocity curve and the mass function of the system. The observing strategy is described and the discovery of two short period hot subdwarf binaries is presented. UVEXJ032855.25+503529.8 contains a hot subdwarf B star (sdB) orbited by a cool M-dwarf in a P=0.11017 days orbit. The lightcurve shows a strong reflection effect but no eclipses are visible. HS 1741+2133 is a short period (P=0.20 days) sdB most likely with a white dwarf (WD) companion.
Neutron stars and stellar-mass black holes are the remnants of massive stars, which ended their lives in supernova explosions. These exotic objects can only be studied in relatively rare cases. If they are interacting with close companions they becom
Hot subdwarfs (sdBs) are core helium-burning stars, which lost almost their entire hydrogen envelope in the red-giant phase. Since a high fraction of those stars are in close binary systems, common envelope ejection is an important formation channel.
Hot subdwarf-B (sdB) stars in long-period binaries are found to be on eccentric orbits, even though current binary-evolution theory predicts these objects to be circularised before the onset of Roche-lobe overflow (RLOF). To increase our understandin
The project Massive Unseen Companions to Hot Faint Underluminous Stars from SDSS (MUCHFUSS) aims at finding hot subdwarf stars with massive compact companions (massive white dwarfs M>1.0 Msun, neutron stars or stellar mass black holes). The existence
Wide hot subdwarf B (sdB) binaries with main-sequence companions are outcomes of stable mass transfer from evolved red giants. The orbits of these binaries show a strong correlation between their orbital periods and mass ratios. The origins of this c