supported by the National Basic Research Program of China (973 program, 2014CB845700);the National Natural Science Foundation of China (Grant Nos. 11322327, 11390374 and 61561053);the Natural Science Foundation of Yunnan Province (Grant Nos. 2013FB083 and 2013HB097)
HD 49798(a hydrogen depleted subdwarf O6 star) with its massive white dwarf(WD) companion has been suggested to be a progenitor candidate of a type Ia supernova(SN Ia). However, it is still uncertain whether the...