EFFECTS OF THE MASS TRANSFER AND PRESENCE OF THE THIRD COMPONENTS IN CLOSE BINARY STELLAR SYSTEMS

In our research, we have studied 6 close binary  stellar  systems  which  are  eclipsing  variables  of  β Lyrae and W Ursae Majoris types of variability. We have studied  their  O-C  curves.  To  build  them,  we  used moments of minima, listed in the BRNO database. Also, we  used  ones,  which  we  obtained  as  the  result  of processing  of  observational  data  taken  from  AAVSO database.  As  the  result  of  the  O-C  analysis,  we  detected that  all  of  these  stars  have  parabolic  O-C  curves,  which might be caused by mass transfer from one component to another.  In  an  addition,  3  from  researched  stars  (U  Peg,V0523  Cas  and  WZ  Cyg)  have  superimposed  parabolic and cyclic O-C changes that could be caused by presence of  the  third  components  in  the  systems.  Also,  we calculated minimal possible masses of third components, rates of the mass transfer for these systems and corrected the ephemerides.