SIMBAD references

We present spectroscopic and photometric observations of the cataclysmic variable HS 1804+6753, a new eclipsing dwarf nova of the U Gem class. Its apparent visual brightness in quiescence is M_v≃14mag. During its frequent outbursts the brightness increases by 1mag-2.3mag. From our photometric data, we determined the orbital period to be P=0.2099370^d±0.0000001^d. The spectroscopic observations show the spectral lines of both stellar components. In quiescence, emission lines of HI, HeI, HeII, CII, and CIII, as well as absorption lines of FeI, FeII, TiII, and OI moving in phase with the primary are visible. During an outburst, additional emission lines of NII, NIII, HeII, and CIII appear. The motion of the secondary can only be derived from a few CaI absorption lines. The orbital inclination of the system is determined to be i=(84.2±0.6)°. From radial velocities of both components, the respective masses are calculated, yielding M₁=(0.75±0.02)M_☉ and M₂=(0.56±0.02)M_☉. The mass ratio derived from photometric data confirms the spectroscopic results. The radii of the two components are calculated to be R₁=(1.3±0.1)x10^–2R_☉ and R₂=(0.57±0.01)R_☉. Several outbursts have been observed so far indicating a relatively high repetition rate.