  Hot subdwarf stars (sdO/Bs) are evolved core helium-burning stars with very
thin hydrogen envelopes, which can be formed by common envelope ejection. Close
sdB binaries with massive white dwarf (WD) companions are potential progenitors
of thermonuclear supernovae type Ia (SN~Ia). We discovered such a progenitor
candidate as well as a candidate for a surviving companion star, which escapes
from the Galaxy. More candidates for both types of objects have been found by
crossmatching known sdB stars with proper motion and light curve catalogues. We
found 72 sdO/B candidates with high Galactic restframe velocities, 12 of them
might be unbound to our Galaxy. Furthermore, we discovered the second-most
compact sdB+WD binary known. However, due to the low mass of the WD companion,
it is unlikely to be a SN\,Ia progenitor.
