Studying the hot subdwarf population with Gaia

Being the stripped cores of red giants, hot subdwarf stars turned out to be important markers of peculiar events in stellar evolution ranging all the way from star-planet interactions to the progenitors of stellar explosions used to measure the expansion of our Universe. With the successful operation of the Gaia mission, the field of stellar astrophysics will soon enter into a new era. The field of hot, evolved stars, which are quite rare, will benefit most significantly because the number of known objects will soon rise by one or two orders of magnitude. Therefore we have to master the transition from analysing single objects to characterising whole populations of objects. In this joint proposal between Tübingen and Bamberg we propose one PostDoc and two PhD positions to compile the first all-sky catalogue of those objects, determine their fundamental parameters and formation channels, study the hot subdwarfs at extreme velocities, and find a new class of progenitors and ejected hypervelocity companions of type Ia supernovae.