Study of an asynchronously rotating polar CD Ind
Abstract
We present X-ray and ultaviolet (UV) analyses of the magnetic cataclysmic variable CD Ind. The X-ray light curves obtained from different observations show a very chaotic and spectacular pattern. X-ray and UV variations occur at orbital periods of (124.0±0.4) and (112.3±0.4) min and spin periods of (119.4±0.4) and (109.8±0.3) min, respectively. The degree of asynchronism of CD Ind is calculated as ~ 2.2% and ~ 3.7% from the UV and X-ray data, respectively. The variable shape of the X-ray and UV light curves indicate that the geometry of accretion changes in every epoch of observations. A two-pole accretion mode geometry is also visible in the X-ray and UV light curves of CD Ind. This two-pole accretion geometry is supported by the presence of double humps or dips in their X-ray and UV light curves. The rotational modulations of UV data are also found to be anti-correlated with respect to the X-rays, revealing that the UV pulsations are not originating in the region of magnetically confined accretion flow. Unlike other magnetic CVs, a strong fluorescent Ni Kα emission line is detected for the first time in the X-ray spectra of CD Ind. The X-ray and UV variations of CD Ind support the view that this system belongs to the class of asynchronous polars.