2002NewA....7..435Q

The century-long times of light minimum of the Algol-type eclipsing binary star, TW Dra (BD+64°1077, SpA5V+K2III), are investigated by considering a new pattern of period change. Two sudden period increases and two successive period decreases are discovered to superimpose on a rapid secular increase (dP/dt=+4.43x106days/year). The secular increase may be caused by a dynamical mass transfer from the secondary to the primary component (dm/dt=6.81x107M☉/year) that is in agreement with the semi-detached configuration of the system and with the existence of a hot spot and a gaseous stream in the binary system. The irregular period jumps superimposed on the secular increase can be explained by the structure variation of the K2-type giant via instabilities of the outer convective layer or via magnetic activity cycles.