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

2. 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

3. 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

4. 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

5. 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)
Msun
P = 5.0 d
Msun
P = 350 d
Msun
P = 130 d
Msun
P = 74 s
Msun
P = 2.0 d
(Webbink 1984)
Msun
P = 190 d
Msun
P = 2.0 d
Msun
P = 0.28 d
Msun
P = 250 s
Delay time distribution of type Ia supernovae Nicki Mennekens
29/09/2009

6. 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

7. 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

8. 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

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

10. 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

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

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

13. 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

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

15. 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

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

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