Hot subdwarfs in close binaries observed from space. II. Analyses of the light variations

Hot subdwarfs in close binaries with either M dwarf, brown dwarf or white companions show unique light variations. In hot subdwarf we can observe the so-called reflection effect and ellipsoidal modulation and/or Doppler beaming. Aims. The analysis of these variations be used to derive mass radius companion hence determine its nature. Thereby assume most probable sdB derived by fit spectral energy distribution Gaia parallax. high signal-to-noise space-based curves from Transiting Exoplanet Survey Satellite K2 space mission, several have been observed much better quality than possible for ground-based observations. allowed us analyse a large sample using lcurve. For first time constrain absolute parameters 19 systems covering periods 2.5 hours masses hydrogen burning limit early dwarfs. Moreover, could eight showing modulations, so far unexplored period range 7 hours. that all but two are likely helium-core Combining our results previously measured rotation velocities seven sdBs short-period binaries. four those agrees tidally locked orbit, other three rotates significantly slower.