• N. B. Sanwal

      Articles written in Journal of Astrophysics and Astronomy

    • Orbital elements of the RS CVn eclipsing binary, SV Camelopardalis

      C. V. S. R. Sarma M. B. K. Sarma N. B. Sanwal

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      The extensiveUBV observations of SV Camelopardalis by Patkos (1982) have been analysed to derive the orbital elements of the system. The data were corrected for the effect of third body (Sarma, Sarma & Abhyankar 1985) and for the ‘RS CVn’ distortion wave (Sarma, Vivekanandarao & Sarma 1988). The cleaned data were used to obtain a preliminary solution by a modified version of Wellmann method (Sarma & Abhyankar 1979) from which we concluded that the primary eclipse is a transit. The final orbital elements of SV Cam were obtained by the modified version (Sarma 1988; Sarmaet al. 1987) of WINK program by Wood (1972). The colour and median brightness variation are discussed. From the spectroscopic mass functionf(m) = 0.118 M (Hiltner 1953), the absolute dimensions of the components are found to be 0.826 Mbd & 0.592 M and 1.236 R & 0.778 R for the primary and secondary components, respectively. The age of the binary system is estimated to be 6.0 ± 1.0 × 108 years

    • BV 690, a new bright Type II Cepheid

      N. B. Sanwal M. B. K. Sarma

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      B andV observations of the suspected variable BV 690 = NSV 04298 are reported. The star shows light variations with a period of ld.2400 and with amplitudes of 0m.27, 0m.36 and 0m.11 inV, B, andB-V respectively. The light curves show steeper rise than decline, and there is evidence for the presence of a bump in the descending branch around the phase of 0.35. From considerations of the period, spectral type, presence of the bump and high tangential velocity we conclude that BV 690 belongs to the BL Herculis class of Typen Cepheids

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