Photometric effects of gas streams in Algol systems and their influence on the light curves outside of and within eclipses

New Photometric Study of the Interacting Binary Star System Y Piscium

“…The observed B-, V-, and I-band light curves are shown in Figure 1. There are clear variations following secondary eclipse, similar to those observed by Walter (1973a). In fact, the B light curve shows a post-secondary dip that appears to be deeper than the secondary eclipse itself.…”

“…If we apply the Mezzetti et al (1980) reformulated mass function of f (m) = 0.028, the masses of Y Psc's components would be M primary = 2.44 M and M secondary = 0.64 M , and the primary's mass would seem to be more like that of a much earlier, hotter mainsequence star and is not consistent with our photometric model. The dips in the light curve just past secondary eclipse are interesting and probably real, especially since the dip is deeper in B than in V and I, similar to the variations noted by Walter (1973a) in his early light curves. Since Algol-type binaries are interacting binaries, then this unusual dip may be caused by the gas stream itself or a cooler accretion structure passing in front of the primary star.…”

Mass Transfer Between Stars: Photometric Studies

“…Two examples are Y Piscium (orbital period = 3.7 days) and RV Ophiuchus (orbital period = 3.9 days), both of which show outside-of-eclipse variations in their latest light curves, which are more than 25 years old (Walter, 1973). Can the light curves of these star systems be modelled with eccentric accretion structures and orbital inclinations that lead to apparent eclipses of the primary star by the accretion cloud?…”