A new interpretation for the second peak of T Coronae Borealis outbursts: A tilting disk around a very massive white dwarf

A new interpretation for the second peak of T Coronae Borealis outbursts is proposed based on a thermonuclear runaway (TNR) model. The system consists of a very massive white dwarf (WD) with a tilting accretion disk and a lob e-filling red giant. The first peak of the visual light curve of T CrB outb ursts is well reproduced by the TNR model on a WD close to the Chandrasekha r mass (M-WD greater than or similar to 1.35 M-.), while the second peak is reproduced by the combination of the irradiated M giant and the irradiated tilting disk. The derived fitting parameters are the WD mass M-WD similar to 1.35 M-., the M giant companion mass M-RG similar to 0.7 M-. (0.6-1.0 M- . is acceptable), the inclination angle of the orbit i similar to 70 degree s, and the tilting angle of the disk i(prec) similar to 35 degrees. These p arameters are consistent with the recently derived binary parameters of T C rB.