V344 Lyr: an unusual large-amplitude SU UMa-type dwarf nova with a short supercycle

We studied the large-amplitude SU UMa-type dwarf nova V344 Lyr. A combination of our observations and reports from the Variable Star Network (VSNET) yields an extensive coverage of outbursts between 1994 July and 2001 June. The analysis of these data showed a mean supercycle length of 109.6 d. This value is one of the smallest among known SU UMa-type dwarf novae (except unusual ER UMa-type dwarf novae). The outburst amplitude of V344 Lyr (similar to5.5 mag) is found to be much larger than those (3.5+/-0.3 mag) of SU UMa-type dwarf novae with similar supercycle lengths. Such a deviation of the amplitude of V344 Lyr is difficult to explain using the inclination effect. The extreme outburst parameters of V344 Lyr would require an additional mechanism to effectively reduce the quiescent luminosity or to increase the outburst frequency.