Delay time distribution of type Ia supernovae Nicki Mennekens, Dany Vanbeveren, Jean-Pierre De Greve & Erwin De Donder

Type Ia supernovae Only in multiple star systems Critical for understanding of galactic chemical evolution Standard candle: validation of LCDM cosmological model Thermonuclear deflagration of white dwarf exceeding Chandrasekhar limit Delay time distribution of type Ia supernovae Nicki Mennekens 29/09/2009

Progenitors Single degenerate: white dwarf pushed over Chandrasekhar limit by accretion from main sequence (MS) or red giant (RG) companion Double degenerate: merger of two white dwarfs (WD) after spiral-in due to gravitational wave radiation Which is the most dominant (or both)? Delay time distribution of type Ia supernovae Nicki Mennekens 29/09/2009

Delay Time Distribution DTD = number of supernova Ia (SN Ia) events per unit time, as function of time elapsed since starburst Measured by observations of elliptical (~starburst) galaxies at same metallicity and different redshift, e.g. Totani et al. (2008) Open question: What is the contribution of SD and DD in starburst galaxies? T. Totani, T. Morokuma, T. Oda, M. Doi & Y. Yasuda, PASJ 60, 1327, 2008 Delay time distribution of type Ia supernovae Nicki Mennekens 29/09/2009

Typical DD SN Ia evolutions RLOF with b = 1 (SN Ia at 5.9 Gyr) RLOF with b = 0 (no SN Ia) CE (SN Ia at 0.12 Gyr) 5.6+5.4 Msun P = 5.0 d 6.0+5.4 Msun P = 350 d 1.0+10 Msun P = 130 d 1.0+5.4 Msun P = 74 s 0.91+5.4 Msun P = 2.0 d (Webbink 1984) 0.90+10 Msun P = 190 d 0.80+5.4 Msun P = 2.0 d 0.90+1.3 Msun P = 0.28 d 0.80+0.76 Msun P = 250 s Delay time distribution of type Ia supernovae Nicki Mennekens 29/09/2009

Our work Previous studies by Ruiter et al. (2009), Han & Podsiadlowski (2004) and Yungelson & Livio (2000) We investigate influence of b during RLOF in close binaries Delay time distribution of type Ia supernovae Nicki Mennekens 29/09/2009

Assumptions Updated evolutionary code of De Donder & Vanbeveren (2004) SD progenitors: as given by Hachisu et al. (2008), including mass stripping effect DD progenitors: every evolution resulting in WD-merger exceeding 1.4 Msun I. Hachisu, M. Kato & K. Nomoto, ApJ 679, 1390, 2008 Delay time distribution of type Ia supernovae Nicki Mennekens 29/09/2009

Parameter study Fraction b of RLOF-material accepted by accretor Lost matter leaves system with specific angular momentum of accretor Energy conversion during common envelope phase: Webbink (1984) Delay time distribution of type Ia supernovae Nicki Mennekens 29/09/2009

b = 1 Delay time distribution of type Ia supernovae Nicki Mennekens 29/09/2009

Most important Most SD events are created through WD+MS channel, not WD+RG Most DD events are created through RLOF channel, not common envelope (CE), as shown by DTDs for different b Delay time distribution of type Ia supernovae Nicki Mennekens 29/09/2009

Double degenerate Delay time distribution of type Ia supernovae Nicki Mennekens 29/09/2009

Single degenerate Delay time distribution of type Ia supernovae Nicki Mennekens 29/09/2009

Influence of the CE-scenario DTD is critically affected by description of CE-evolution Alpha-scenario of Webbink (1984): balance of energy vs. gamma-scenario of Nelemans & Tout (2005): balance of angular momentum (for WD-binary evolution) Delay time distribution of type Ia supernovae Nicki Mennekens 29/09/2009

b = 1, gamma-scenario Delay time distribution of type Ia supernovae Nicki Mennekens 29/09/2009

Conclusions Most DD SN Ia are created through RLOF channel Resulting critical dependency of DTD on mass transfer efficiency during RLOF and physics of CE  a way to find out more about these processes? Delay time distribution of type Ia supernovae Nicki Mennekens 29/09/2009

Delay time distribution of type Ia supernovae Nicki Mennekens 29/09/2009

Results Delay time distribution of type Ia supernovae Nicki Mennekens 29/09/2009