SNe Ia Rates SNe Ia Rates & Delay Times & Delay Times

Xu XiaojieXu Xiaojie

OutlineOutline

SNIa rates and delay timesSNIa rates and delay times Several ConsiderationsSeveral Considerations CalculatingCalculating First resultsFirst results

SNIa Rates & Delay timesSNIa Rates & Delay times SNIa rates: ~3*10^-3/year for milky waSNIa rates: ~3*10^-3/year for milky wa

y like galaxyy like galaxy Delay time: time from the birth of the Delay time: time from the birth of the

progenitor system to the explosion of tprogenitor system to the explosion of the SNhe SN

Rates and Delay times could be used to Rates and Delay times could be used to constrain the progenitor model constrain the progenitor model

SNIa Progenitor ModelSNIa Progenitor Model SD model: CO WD accreting from comSD model: CO WD accreting from com

panionpanion DD model: 2 CO WDs mergeDD model: 2 CO WDs merge SD use to be the favored one, yet the prSD use to be the favored one, yet the pr

ogenitor is concerned as super soft souogenitor is concerned as super soft sources---there are just not enough SSSs rces---there are just not enough SSSs

DD model facing similar problemsDD model facing similar problems

Some ConsiderationsSome Considerations

‘‘Prompt’ SNIa is still hard to explain Prompt’ SNIa is still hard to explain Other works limitations: liability of H burOther works limitations: liability of H bur

ning efficiency assumption, and the He bning efficiency assumption, and the He burning ‘optical thick wind’ modelurning ‘optical thick wind’ model

Liability of 100% binariesLiability of 100% binaries Irradiation to the companion from the WIrradiation to the companion from the W

DD Possible answer for lack of SSS: wind froPossible answer for lack of SSS: wind fro

m the companion?m the companion?

Basic IdeasBasic Ideas

Mass flow from companion Mass flow from companion check thermal instability of accretion discheck thermal instability of accretion disk k H burning & accumulation ratio H burning & accumulation ratio He burning & accumulation ratioHe burning & accumulation ratiocheck L from burning and accretion check L from burning and accretion Eddington limit of accretion Eddington limit of accretion total accumulation ratio etatotal accumulation ratio etareal L from burning and accretionreal L from burning and accretion companion irradiation windcompanion irradiation windnext timestepnext timestep

Mass & Angular Momentum Mass & Angular Momentum LossLoss

Roche lobe overflowRoche lobe overflow Stellar wind (Hurley’s consideration, Stellar wind (Hurley’s consideration,

4 different kinds of stellar wind)4 different kinds of stellar wind) Matter ejected from the companion Matter ejected from the companion

and the WD carrying away A.M.and the WD carrying away A.M. Updated Magnetic Braking from Updated Magnetic Braking from

companion with convective zonescompanion with convective zones Gravitational wavesGravitational waves

Disk Thermal Instability & Disk Thermal Instability & Duty CyclesDuty Cycles

H AcculumationH Acculumation

Luminosity of WD Luminosity of WD

Considering the total accumulation of Considering the total accumulation of matter after accretion and H burningmatter after accretion and H burning

L=L_accretion + L_nuclearburningL=L_accretion + L_nuclearburning =eta_acc*M_rlof =eta_acc*M_rlof + eta_nuc*M_rlof*(eta_H*eta_He) + eta_nuc*M_rlof*(eta_H*eta_He)

If eta_H<0, then only L_acc includedIf eta_H<0, then only L_acc included If L>L_edd, then If L>L_edd, then

etatotal = eta_H*eta_He*eta_eddetatotal = eta_H*eta_He*eta_edd

Companion’s Irradiation Companion’s Irradiation WindWind

CalculatingCalculating

M_wd: 0.8, 0.9, 1.0, 1.1, 1.2 M_sM_wd: 0.8, 0.9, 1.0, 1.1, 1.2 M_s M_companion: 1.0 to 8.0 M_sM_companion: 1.0 to 8.0 M_s Initial P: logP from -0.3 to 1.0d (0.5—10 Initial P: logP from -0.3 to 1.0d (0.5—10

days)days) Totally 3500 systemsTotally 3500 systems

Wangbo’s ResultsWangbo’s Results

Our First ResultOur First Result

Delay Time after Birth of Delay Time after Birth of WDWD

Delay Time 3DDelay Time 3D

Still Working…Still Working…

Other M_wd rangeOther M_wd range Binary Population synthesis codeBinary Population synthesis code Interpolation methodInterpolation method