2MASS J0516288+260738: Discovery of the first eclipsing late K+ Brown dwarf binary system?

We report the discovery of a new eclipsing system less than one arcminute south of the pulsating DB white dwarf KUV 05134+2605. The object could be identified with the point source 2MASS J0516288+260738 published by the Two Micron All Sky Survey. We present and discuss the first light curves as well as some additional colour and spectral information. The eclipse period of the system is 1.29 d, and, assuming this to be identical to the orbital period, the best light curve solution yields a mass ratio of m(2)/m(1) = 0.11, a radius ratio of r(2)/r(1) approximate to 1 and an inclination of 74degrees. The spectral anaylsis results in a T-eff = 4200 K for the primary. On this basis, we suggest that the new system probably consists of a late K + Brown dwarf (which would imply a system considerably younger than approximate to 0.01 Gyr to have r(2)/r(1) approximate to 1), and outline possible future observations.