We present a theoretical light curve model of the recurrent nova M31N 2008-12a , the current record holder for the shortest recurrence period ( 1 yr ) .
We combined interior structures calculated using a Henyey-type evolution code with optically thick wind solutions of hydrogen-rich envelopes , which give the proper mass-loss rates , photospheric temperatures , and luminosities .
The light curve model is calculated for a 1.38 M _ { \sun } white dwarf ( WD ) with an accretion rate of 1.6 \times 10 ^ { -7 } ~ { } M _ { \sun } yr ^ { -1 } .
This model shows a very high effective temperature ( \log T _ { ph } ( K ) \geq 4.97 ) and a very small wind mass-loss rate ( \dot { M } _ { wind } \leq 9.3 \times 10 ^ { -6 } ~ { } M _ { \sun } yr ^ { -1 } ) even at the maximum expansion of the photosphere .
These properties are consistent with the faint optical peak of M31N 2008-12a because the brightness of the free–free emission is proportional to the square of the mass-loss rate .
The model well reproduces the short supersoft X-ray turn-on time of 6 days and turnoff time of 18 days after the outburst .
The ejecta mass of our model is calculated to be 6.3 \times 10 ^ { -8 } ~ { } M _ { \sun } , corresponding to 37 % of the accreted mass .
The growth rate of the WD is 0.63 times the mass accretion rate , making it a progenitor for a Type Ia supernova .
Our light curve model predicts a bright supersoft X-ray phase one or two days before the optical peak .
We encourage detection of this X-ray flash in future outbursts .