The Close Binary System TX Cancri
Atsuma Yamasaki, M. Kitamura · Publications of the Astronomical Society of Japan · 1972
Abstract TX Cnc is studied from the UB V and narrow-band photoelectric light curves, Hβ photometry, and Cassegrain spectrograms. The combined spectral type of the system at light maximum is estimated to be G1V. The light curves, obtained over nine years, reveal that there are conspicuous asymmetries and variations among them. These may be attributed to the possible existence of some unstable gaseous envelope. It is found that the system increased its orbital period abruptly around 1959. The period change had occurred probably due to a mass-transfer of the order of 10−6M◉, from the secondary component to the primary, or due to a mass-loss of the same order from the system, with little change of the orbital angular momentum. New light elements are determined from all the data after the period change. The mean B- and V-light curves are analyzed and the most plausible photometric elements are obtained to be i=58°, ra=0.30, rb=0.46, La=0.35, and Lb=0.65. Combining these results with Popper’s (1948) spectroscopic data, the masses and the radii of the components are deduced to be 3M1=1.53M◉, R1=0.793M◉, R1=1.36R◉, and R2=0.88R◉, and the luminosities are deduced for the distance modulus of the Praesepe cluster m—M=6m.1 to be L1=1.4L◉ and L2=0.75L◉. It is highly difficult to explain the relation among the masses, radii, and luminosities of the components by any theoretical model currently proposed.