The Eclipsing Cataclysmic Variable Lanning 386: Dwarf Nova, SW Sextantis Star, or Both?

摘要

We present photometry and spectroscopy of the suspected cataclysmic variable(CV) Lanning 386. We confirm that it is a CV, and observe deep eclipses, fromwhich we determine the orbital period Porb to be 0.1640517 +- 0.0000001 d (=3.94 h). Photometric monitoring over two observing seasons shows a very activesystem with frequent outbursts of variable amplitude, up to approx. 2 mag. Thespectrum in quiescence is typical of dwarf novae, but in its high state thesystem shows strong HeII emission and a broad CIV Wolf-Rayet feature. This isunusual for dwarf novae in outburst and indicates a high excitation. In itshigh state the system shows some features reminiscent of an SW Sextantis-typeCV, but lacks others. We discuss the classification of this puzzling object.