Symmetry Breaking for Black–Scholes Equations

Yang Xuan-Liu, Zhang Shun-Li, Qu Chang-Zheng
2007 Communications in Theoretical Physics  
We explore the possibility that the G2 gas cloud falling in toward SgrA * is the mass-loss envelope of a young T Tauri star. As the star plunges to smaller radius at 1000-6000 km s −1 , a strong bow shock forms where the stellar wind is impacted by the hot X-ray emitting gas in the vicinity of SgrA * . For a stellar mass-loss rate of 4 × 10 −8 M yr −1 and wind velocity 100 km s −1 , the bow shock will have an emission measure (EM = n 2 vol) at a distance ∼10 16 cm, similar to that inferred from
more » ... that inferred from the IR emission lines. The ionization of the dense bow shock gas is potentially provided by collisional ionization at the shock front and cooling radiation (X-ray and UV) from the post shock gas. The former would predict a constant line flux as a function of distance from SgrA * , while the latter will have increasing emission at lesser distances. In this model, the star and its mass-loss wind should survive pericenter passage since the wind is likely launched at 0.2 AU and this is much less than the Roche radius at pericenter (∼3 AU for a stellar mass of 2 M ). In this model, the emission cloud will probably survive pericenter passage, discriminating this scenario from others.
doi:10.1088/0253-6102/47/6/006 fatcat:nh3eauk5gfaefnfo5im3vek3ky