MN Dra - In-the-Gap Dwarf Nova With Negative Superhumps

TL;DR

This study presents extensive photometric observations of MN Dra, a dwarf nova exhibiting both positive and negative superhumps, revealing cyclic period changes and confirming its unique in-the-gap classification.

Contribution

First detailed multi-site photometric analysis of MN Dra capturing its superoutbursts and superhump behavior, highlighting its in-the-gap dwarf nova nature with negative superhumps.

Findings

Detected negative superhumps with cyclic period variations

Confirmed large period decrease during superoutburst

Observed multiple normal and superoutbursts

Abstract

The multi-site photometric observations of MN Dra were made over 77 nights in August-November, 2009. The total exposure was 433 hours. During this time the binary underwent two superoutbursts and five normal outbursts. During the course of first superoutburst period of positive superhumps decreased with extremely large $\dot P = -1.5 \times 1.0^{-4}$ for SU UMa-like dwarf novae, confirming known behavior of MN Dra [1]. Between the superoutbursts MN Dra displayed negative superhumps. Their period changed cyclically around 0.096-day value.