A Photometry Campaign for IR Geminorum in Quiescence
We report a V band photometry of the SU UMa star IR Gem at quiescence in January 2002. The observations were made with two telescopes spaced ～ 160° apart in longitude. Several photometric modulations have been found. One gives a period of 98.50(13) min, exactly equal to the orbital period determined spectroscopically. Two others occasionally strengthen and seem to be positive and negative superhumps with periods of 103.6(4) and 95.4(4) min, 5.2% longer and 3.1% shorter than the orbital period, respectively. A signal at ～ 0.6 c/d in the power spectrum is roughly consistent with the expected period of nodal precession of the disk. There is a puzzling peak at 0.21(3) c/d corresponding to the ～ 4.3 d sine wave seen in the raw light curve. We suspect it to be a beat frequency between the frequencies of apsidal and nodal precessions of the disk. Quasi-periodic cycles with amplitudes 0.15-0.6 mag can be seen in the light curve. The mechanism underlying this modulation is not clear.
作 者： Hai Fu Zong-Yun Li Kam-Ching Leung Zhou-Sheng Zhang Zi-Li Li C.Martin Gaskell 作者单位： Hai Fu,Zong-Yun Li(Department of Astronomy, Nanjing University, Nanjing 210093)Kam-Ching Leung,C.Martin Gaskell(Department of Physics and Astronomy, University of Nebraska, Lincoln NE 68588-0111, USA)
Zhou-Sheng Zhang,Zi-Li Li(Yunnan Observatory, Kunming 650011)
刊 名： 天体物理学报(英文版) ISTIC SCI 英文刊名： CHINESE JOURNAL OF ASTRONOMY AND ASTROPHYSICS 年，卷(期)： 2004 4(1) 分类号： P1 关键词： accretion accretion disks - binaries: close - novae cataclysmic variables - stars: dwarf nova - stars: individual (IR Geminorum)