Context :

Aims : System parameters of the object LTT 560 are determined in order to clarify its nature and evolutionary status .

Methods : 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 .

Results : We find that LTT 560 is composed of a low temperature ( T \sim 7500 K ) DA white dwarf as the primary and an M 5.5 \pm 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 - 40 pc .
Long-term variation of the orbital light curve and an additional H \alpha emission component on the white dwarf indicate activity in the system , probably in the form of flaring and/or accretion events .

Conclusions :