The 2006 November outburst of EG Aquarii: the SU UMa nature revealed

• Published in: arXiv.org 2008-05
• Main Authors: Imada, Akira, Stubbings, Rod, Kato, Taichi, Uemura, Makoto, Krajci, Thomas, Torii, Ken'ichi, Sugiyasu, Kei, Kubota, Kaori, Moritani, Yuuki, Ishioka, Ryoko, Masi, Gianluca, Kiyota, Seiichiro, Monard, L A G, Maehara, Hiroyuki, Nakajima, Kazuhiro, Arai, Akira, Ohsugi, Takashi, Yamashita, Takuya, Kawabata, Koji S, Nagae, Osamu, Chiyonobu, Shingo, Fukazawa, Yasushi, Mizuno, Tsunefumi, Katagiri, Hideaki, Takahashi, Hiromitsu, Ueda, Atsushi, Hayashi, Takehiro, Okita, Kiichi, Yoshida, Michitoshi, Yanagisawa, Kenshi, Sato, Shuji, Kino, Masaru, Kitagawa, Masahiro, Sadakane, Kozo, Nogami, Daisaku
• Format: Article
• Language: English
• Subjects: Cataclysmic variables; Dwarf novae; Light curve; Novae; Outbursts; Photometry; Precursors; Superhumps (astronomy)
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.0805.4111

We report time-resolved CCD photometry of the cataclysmic variable EG Aquarii during the 2006 November outburst During the outburst, superhumps were unambiguously detected with a mean period of 0.078828(6) days, firstly classifying the object as an SU UMa-type dwarf nova. It also turned out that the outburst contained a precursor. At the end of the precursor, immature profiles of humps were observed. By a phase analysis of these humps, we interpreted the features as superhumps. This is the second example that the superhumps were shown during a precursor. Near the maximum stage of the outburst, we discovered an abrupt shift of the superhump period by \({\sim}\) 0.002 days. After the supermaximum, the superhump period decreased at the rate of \(\dot{P}/P\)=\(-8.2{\times}10^{-5}\), which is typical for SU UMa-type dwarf novae. Although the outburst light curve was characteristic of SU UMa-type dwarf novae, long-term monitoring of the variable shows no outbursts over the past decade. We note on the basic properties of long period and inactive SU UMa-type dwarf novae.