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Xu Xiaojie 2009/05/20 reference : King & Pringle, arXiv: 0905.0637 Dewi & Tauris, 2000, A&A 360, 1043. RS Oph : Unstable Disk Model. ABCs of RS Oph. P=453.5 d, evolved giant companion (CVs have main sequence companion)
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Xu Xiaojie 2009/05/20 reference : King & Pringle, arXiv: 0905.0637 Dewi & Tauris, 2000, A&A 360, 1043 RS Oph :Unstable Disk Model
ABCs of RS Oph P=453.5 d, evolved giant companion (CVs have main sequence companion) Nova, Recurrent cycle ~ 21yrs (1898--2006), relatively short; Bursting model:1. unstable H burning on a massive WD (~1.35M_s) surface, possible SN Ia progenitor 2. unstable accretion disk varying accretion rate, no heavy WD needed
Observational Properties Mixing of accreted matter and those of WD can cause WD matter lost during flashes: C, N, O, Ne, but no significant sign for RS Oph Well-collimated jets produced during the outburst in 2006 Sources harboring jets ( quasars, microquasars, some X-ray binaries) have following in common:disk accretion, high jet velocity, 10% accreted matter expelled,
Theoretical Difficulties For nuclear bursting, to accumulate matter for outburst, accretion rate requires While RS Oph lack of X-ray during quiescence Matter in disk easily blow away no jets Nuclear burning hard to produce jets
Disk Model P=453.5d a ~1.4AU Stable accretion requires M_2< M_1 Stellar wind accretion ruled out RLOF forms an accretion disk, with outer radius ~ 70% WD roche lobe, size ~0.5a ~ 0.7AU ~ 10^12cm T of outer accretion disk less than 6500K Disk unstable
Pros of Unstable Disk Explanation of rising and decaying of outburst Jets Mass transfer rate Large accretion disk Dynamical determination of the WD mass?
Classic Evolution Path II *2 mass less than WD mass ~~*2 accreted little matter~~ CE favored Orbital shrinking during CE, why P~450d
CE? • Less energy dissipation on CE phase • Binding energy of the envelope • Total change in orbital energy • Energy converting efficiency
Ejection & Binding Parameter • Final separation • The actual binding energy