This is a photometric study of the dwarf nova MN Dra made during 2012-2017 on nine telescopes over 152 nights. Overall, the observations covered 4 superoutbursts, 7 normal outbursts and the quiescent state. The interval between neighboring superoutbursts in 2017 was 65 days, and between neighboring normal bursts, 15 days. During the superoutbursts of 2012 and 2017, positive superhumps with a period of 0.10558( 6 ) and 0.10500( 2 ) days, respectively, were observed and in the quiescent state, negative superhumps with an average period of 0.095921( 3 ) days, It is shown that the period of the negative superhumps varied cyclically between normal outbursts: sharply decreasing during an outburst and gradually increasing toward the onset of the next outburst. This feature of the variation in the period of the negative superhumps may correspond to a rapid increase in the radius of the accretion disk during the time of an outburst followed by a slow decrease, in agreement with the theory of thermal-tidal instability.

中文翻译：

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SU UMa型矮新星负超驼峰时期的变化。I. Mn Dra (2012-2017)

这是对 2012 年至 2017 年期间在 9 个望远镜上进行的 152 个夜晚矮新星 MN Dra 的光度学研究。总体而言，观测涵盖了 4 次超级爆发、7 次正常爆发和静止状态。2017年相邻的超级爆发间隔为65天，相邻的正常爆发间隔为15天。在 2012 年和 2017 年的超爆发期间，分别观测到周期为 0.10558( 6 ) 和 0.10500( 2 ) 天的正超峰，在静止状态下，平均周期为 0.095921( 3 ) 天的负超峰是表明负超级驼峰的周期在正常爆发之间周期性变化：在一次爆发期间急剧减少，并在下一次爆发开始时逐渐增加。