We have been proposing two evolutionary paths to Type Ia supernovae ( SNe Ia ) , which are called the supersoft X-ray source ( SSS ) channel and the symbiotic channel , depending on the orbital separation just prior to an SN Ia explosion .
The essential difference of our treatment is inclusion of strong , optically thick winds on mass-accreting white dwarfs ( WDs ) in the elementary processes of binary evolution when the mass accretion rate on to WDs exceeds a critical rate of \dot { M } _ { cr } \sim 1 \times 10 ^ { -6 } M _ { \odot } yr ^ { -1 } .
Once optically thick winds begin to blow from the WD , the binary can avoid forming a common envelope in some cases .
We call this accretion wind .
So that the WDs are able to grow up to the Chandrasekhar mass and explode as an SN Ia , showing SSS or recurrent nova phenomena in the way to SNe Ia .
Thus , the accretion wind process of WDs can open new channels to SNe Ia .
We have modeled the LMC supersoft source RX J0513.9-6951 as an example of the systems in the accretion wind phase .
Further inclusions of two other elementary processes make the channels much wider ; these are the case BB mass transfer in the SSS channel and the strong orbital shrinkage during the superwind phase of the primary star in the symbiotic channel .
As a result , the estimated birth rate of SNe Ia via these two channels becomes compatible with the observation in our Galaxy .
Interestingly , the U Sco and T CrB subclasses of recurrent novae can be naturally understood as a part of evolutionary stages in these two SSS and symbiotic channels to SNe Ia , respectively .
Thus we have a unified picture of binary evolutions to SNe Ia , luminous SSS , and recurrent novae .