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 +/- 10.04)keV for Raymond-Smith model while the column density fixed at 0.54 x 10(-21) cm(-2). The estimated 0.1-2.4 keV flux is found to be in the range of between logF = -13 and logF = -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 logL = 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) x 10(21) gs(-1) for the blackbody model and (2.2 +/- 0.052) x 10(19) gs(-1) for Raymond-Smith model. As a result of our study it seems that the system El 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