A CE-wind model for SNe Ia

Xiangcun MengYunnan Observatories

Philipp PodsiadlowskiOxford University

Supernova

• Extremely bright stellar explosion

• Important for the production of the heavy elements

• Best distance indicators in the universe

The only reliable way of determining extragalactic distances is through supernova investigations. F. Zwicky

redshift

distance

Distance indicator:

An accelerating -expansion universe !

• Riess A. et al., 1998, 2004• Perlmutter S. et al., 1999

• Tonry et al., 2003

Lum

inos

ity

time

Phillips relation

Understanding of type Ia Supernovae

What we know about SNe Ia:• Light Curves (temporal evolution of photometry)• Spectra (UV, optical, NIR)• Some relationships about SNe Ia

Complex and simple theoretical models and simulations which reproduce observations very well

Branch+, 1985

Open questions

• Progenitor model.

• Explosion model.

• Burning flame.

• Evolution with redshift.

• Origin of luminosity scatter.

CO WD + star2 SN Ia

Single Degenerate Model

CO WD + MS, RG, Helium

Double Degenerate modelCO WD + CO WD

• Hydrogen shell burningNomoto, 1982

• In 1996 Hachisu Kato & Nomoto proposed an optically thick wind (OTW) model.

• Unprocessed matter is lost from the

system as the OTW.

Hachisu et al.1996,1999

Question!

• Metallicity dependent

• OTW velocity

• How to adjust the helium flash and hydrogen burning.

CEW model

• Do not depend on metallicity.

• Low wind velocity.

• No fine-tuning

• Explain the number of SSSs.

• Explain the properties of RNe.

The birth rate of SNe Ia from our CEW model is higher than that from OTW model by about 30%！

Produce 2002ic-like supernova！Explain high-velocity feature！

Our model is quite robust!

Summary• Do not depend on metallicity• Wind velocity could be lower than 50~ 200 km/s.• Adjust helium flash itself.• May explain the number of SSSs.• May explain the properties of RNs.• The birth rate from the CE-Wind model is higher

than that from the OTW model by about 30%.• May produce 2002ic-like SN.

• May naturally explain the HVF of SNe Ia.• The CEW model is quite robust.

Share the merits of the OTW model, but conquer its shortcomings!

Thank you!

Outline

Supernova types

Introduction

CE-wind model