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SNe Ia Rates & Delay Times

SNe Ia Rates & Delay Times. Xu Xiaojie. Outline. SNIa rates and delay times Several Considerations Calculating First results. SNIa Rates & Delay times. SNIa rates: ~3*10^-3/year for milky way like galaxy Delay time: time from the birth of the progenitor system to the explosion of the SN

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SNe Ia Rates & Delay Times

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  1. SNe Ia Rates & Delay Times Xu Xiaojie

  2. Outline • SNIa rates and delay times • Several Considerations • Calculating • First results

  3. SNIa Rates & Delay times • SNIa rates: ~3*10^-3/year for milky way like galaxy • Delay time: time from the birth of the progenitor system to the explosion of the SN • Rates and Delay times could be used to constrain the progenitor model

  4. SNIa Progenitor Model • SD model: CO WD accreting from companion • DD model: 2 CO WDs merge • SD use to be the favored one, yet the progenitor is concerned as super soft sources---there are just not enough SSSs • DD model facing similar problems

  5. Some Considerations • ‘Prompt’ SNIa is still hard to explain • Other works limitations: liability of H burning efficiency assumption, and the He burning ‘optical thick wind’ model • Liability of 100% binaries • Irradiation to the companion from the WD • Possible answer for lack of SSS: wind from the companion?

  6. Basic Ideas • Mass flow from companion  check thermal instability of accretion disk H burning & accumulation ratio He burning & accumulation ratiocheck L from burning and accretion Eddington limit of accretion total accumulation ratio etareal L from burning and accretion companion irradiation windnext timestep

  7. Mass & Angular Momentum Loss • Roche lobe overflow • Stellar wind (Hurley’s consideration, 4 different kinds of stellar wind) • Matter ejected from the companion and the WD carrying away A.M. • Updated Magnetic Braking from companion with convective zones • Gravitational waves

  8. Disk Thermal Instability & Duty Cycles

  9. H Acculumation

  10. Luminosity of WD • Considering the total accumulation of matter after accretion and H burning • L=L_accretion + L_nuclearburning =eta_acc*M_rlof + eta_nuc*M_rlof*(eta_H*eta_He) • If eta_H<0, then only L_acc included • If L>L_edd, then etatotal = eta_H*eta_He*eta_edd

  11. Companion’s Irradiation Wind

  12. Calculating • M_wd: 0.8, 0.9, 1.0, 1.1, 1.2 M_s • M_companion: 1.0 to 8.0 M_s • Initial P: logP from -0.3 to 1.0d (0.5—10 days) • Totally 3500 systems

  13. Wangbo’s Results

  14. Our First Result

  15. Delay Time after Birth of WD

  16. Delay Time 3D

  17. Still Working… • Other M_wd range • Binary Population synthesis code • Interpolation method

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