Recent discovery of several overluminous type Ia supernovae ( SNe Ia ) indicates that the explosive masses of white dwarfs may significantly exceed the canonical Chandrasekhar mass limit .
Rapid differential rotation may support these massive white dwarfs .
Based on the single-degenerate scenario , and assuming that the white dwarfs would differentially rotate when the accretion rate \dot { M } > 3 \times 10 ^ { -7 } M _ { \odot } yr ^ { -1 } , employing Eggleton ’ s stellar evolution code we have performed the numerical calculations for \sim 1000 binary systems consisting of a He star and a CO white dwarf ( WD ) .
We present the initial parameters in the orbital period - helium star mass plane ( for WD masses of 1.0 ~ { } M _ { \odot } and 1.2 ~ { } M _ { \odot } , respectively ) , which lead to super-Chandrasekhar mass SNe Ia .
Our results indicate that , for an initial massive WD of 1.2 ~ { } M _ { \odot } , a large number of SNe Ia may result from super-Chandrasekhar mass WDs , and the highest mass of the WD at the moment of SNe Ia explosion is 1.81 M _ { \odot } , but very massive ( > 1.85 M _ { \odot } ) WDs can not be formed .
However , when the initial mass of WDs is 1.0 ~ { } M _ { \odot } , the explosive masses of SNe Ia are nearly uniform , which is consistent with the rareness of super-Chandrasekhar mass SNe Ia in observations .