Possible pulsations of the M giant in MWC560

Abstract

MWC 560 and other peculiar symbiotic binary, CH Cyg, have been classified as the prototypes of the new subclass of symbiotic systems - propellers, with accretion onto a magnetic white dwarf being the source of activity. The companion of the hot component in this model should demonstrate stellar wind with relatively high mass-loss. It can be expected rather a late AGB, Mira or semiregular variable (SR) than any normal red giant.Our analysis performed for the I band shows that the M giant probably belongs to such kind of stars and pulsates with a period of about 5 months.