Optical CCD photometry and Rosat X-ray spectral analysis of the shortest period CV EI Psc (1RXS J232953.9 + 062814)

Abstract

We present here the optical observations of EI Psc (1RXS J232953.9 + 062814) through Turkish National Observatory (TUG) with RTT150 cm Russian–Turkish joint telescope and its X-ray observation using the ROSAT archival data. Our optical observations reveal a period of 0.0408 days (58.75 min) which is rather different from its early value of 0.046 days (66.24 min) as reported by [Schmeer, P., 2001. vsnet-alert6830, < http://www.kusastro.kyoto-u.ac.jp/vsnet/Mail/vsnet-alert/mgs06830.html>]. Also possible periodicities as well as any QPOs are studied without having any clear indication of it. Archival ROSAT RASS data are also analyzed for its X-ray spectra. The raw data were fitted with various spectral models and the best fit models are found to be that of Blackbody and Raymond–Smith with best fit temperatures of kT = ( 0.07 ± 0.02 ) keV for blackbody model and kT = ( 0.13 ± 0.04 ) keV for Raymond–Smith model while the column density fixed at 0.54 × 10 - 21 cm - 2 . The estimated 0.1–2.4 keV flux is found to be in the range of between log F = - 13 and log F = - 14 erg cm - 2 s - 1 . The model dependent luminosity values were in the range of log L = 29 erg s - 1 for Raymond–Smith model and log L = 31 erg s - 1 for blackbody model. Using the well fitted temperature values, the mass of the primary value that is obtained by [Uemura, M., Kato, T., Ishioka, R., Yamaoka, H., Scgmeer, P., Starkey, D.R., Torii, K., Kawai, N., Urata, Y., Kohama, M., Yoshida, A., Ayani, K., Kawabata, T., Tanabe, K., Matsumoto, K., Kiyota, S., Pietz, J., Vanmunster, T., Krajci, T., Oksanen, A., Giambersio, A., 2002b. Superhump Evolution in the Ultrashort Period Dwarf Nova 1RXS J232953.9 + 062814. PASJ 54, 599–607] and the equations taken from literature, the mass accretion rate in the boundary layer is obtained to be ( 1.58 ± 0.14 ) × 10 21 gs - 1 for the blackbody model and ( 2.2 ± 0.052 ) × 10 19 gs - 1 for Raymond–Smith model. As a result of our study it seems that the system EI Psc has a very high mass accretion rate; and because of the observed soft X-ray photons and high mass accretion rates it has an optically thick boundary layer and M-type secondary star which can be a Brown Dwarf.