2007A&A...474..205T

System parameters of the object LTT560 are determined in order to clarify its nature and evolutionary status. We apply time-series photometry to reveal orbital modulations of the light curve, time-series spectroscopy to measure radial velocities of features from both the primary and the secondary star, and flux-calibrated spectroscopy to derive temperatures of both components. We find that LTT560 is composed of a low temperature (T∼7500K) DA white dwarf as the primary and an M5.5±1 main-sequence star as the secondary component. The current orbital period is P_orb=3.54(07)h. We derive a mass ratio M_sec/M_wd=0.36(03) and estimate the distance to d=25-40pc. Long-term variation of the orbital light curve and an additional Hα emission component on the white dwarf indicate activity in the system, probably in the form of flaring and/or accretion events.