Supernovae from 8-12M stars: new stellar models€¦ · URCA pairs: 27Al $27Mg; 25Mg $25Na; 23Na...

Supernovae from 8− 12 M� stars: new stellarmodels

Samuel Jones

Keele University, UK

Oct. 2013

In collaboration with: R. Hirschi (Keele, UK), K. Nomoto (IMPU, Japan), T. Fischer (TU Darmstadt, Germany), F. X. Timmes (ASU, USA), F. Herwig (UVic,

Canada), B. Paxton (KITP, UCSB, USA), H. Toki (Osaka University, Japan), T. Suzuki (Nihon University, Japan), G. Martinez-Pinedo (TU Darmstadt,

Germany), Y. H. Lam (TU Darmstadt, Germany), M. Bertolli (Los Alamos, USA)

Jones, S. (Keele University) 8–12 M�stars Oct. 2013 1 / 17

Outline

SN-II progenitor evolution overview

Motivation for studying 8− 12 M� stars

new ECSN progenitor models

Importance of weak reaction rates

Jones, S. (Keele University) 8–12 M�stars Oct. 2013 2 / 17

Massive stars - CCSN progenitorsM & 10M�:

Central H, He, C, Ne, O, Si burning→ Fe core→ e−-captures→ collapse→explosion

see e.g. Heger et al. 2003

Jones, S. (Keele University) 8–12 M�stars Oct. 2013 3 / 17

Super-AGB stars - EC-SN progenitors?

H, He, C burning→ ONe core growth→ e−-captures→ O delfagration→ Fecore→ e−-captures→ collapse→ explosion

Miyaji et al. (1980), Nomoto (1984, 1987), Miyaji & Nomoto (1987), Ritossa et al. (1999),Poelarends et al. (2008), Takahashi et al. (2013)

Jones, S. (Keele University) 8–12 M�stars Oct. 2013 4 / 17

Motivation

N(8− 12 M�)/N(M > 8 M�) = 0.42see also Jennings et al. (2012)

Distinct lack of low mass SNIIprogenitor models(Nomoto ’84, ’87; Takahashi et al.2013 & Poster 10)

HMXB spin period/orbital eccentricitybimodality(Knigge et al. 2011)

Abundance anti-/correlations (Hansenet al. 2012) - second (weak)r-process?

Electron capture supernovanucleosynthesis. weak r-process?

2-D simulations produce n-richpockets with Ye,min = 0.4

Wanajo et al. (2011)

- no r-process (not even Pd or Ag)

Other contributions - gap in GCEmodels; 48Ca, 60Fe (Wanajo et al.,2013).

Jones, S. (Keele University) 8–12 M�stars Oct. 2013 5 / 17

Transition evolution: super-AGB→ massive star

(c) 8.75

H He C

(d) 8.8

H He C

He

Ne+O

(e) 9.5

H He C Ne+OSi

He

H He C Ne O Si

He

(f) 12.0

Convection is a 3D phenomenon!

Jones, S. (Keele University) 8–12 M�stars Oct. 2013 6 / 17

C

Ne

O

Si

Ne-flash

Si-flame

Ne-flame

URCA

Jones, S. (Keele University) 8–12 M�stars Oct. 2013 7 / 17

8.75 and 8.8 M� models - weak interactions

Both SAGB (8.75 Mo) and failed massive stars (8.8 Mo) may produce anECSN

URCA pairs: 27Al↔ 27Mg; 25Mg↔ 25Na; 23Na↔ 23Ne

URCA cooling

Ne+O shell flashes

Ne-burning

O-deflagration

A=25

A=23A=27

(Not modelled in this work)

Ne + e20 -

Jones, S. (Keele University) 8–12 M�stars Oct. 2013 8 / 17

C

Ne

O

Si

Ne-flash

Si-flame

Ne-flame

URCA

CCSN

CCSN?ECSN

ECSN

ONe WD ONe WD

Jones, S. (Keele University) 8–12 M�stars Oct. 2013 9 / 17

Weak rates - problems and solutions

log〈ft〉Sufficient resolution to determinethreshold densities.

λ(24Mg(e−, ν)24Na) at T9 = 0.4

9.0 9.5 10.0 10.5 11.0

log10(�Ye/g cm�3 )

�25

�20

�15

�10

�5

0

5

log10(�

/s�

1)

Oda et al. (1994)

Takahara et al. (1989)

Consistent e±-capture, β±-decay,ν-loss rates.

Coulomb corrections.

Gutierrez et al. (1996) - only ratecorrections.

Jones, S. (Keele University) 8–12 M�stars Oct. 2013 10 / 17

New SD-shell rates (URCA pairs)Results using A=23, 25, 27 pairs (Toki et al. 2013) in MESAZ = 0.014, 10−3, 10−5; M = 8.8, 7.7, 7.76 M�.

A=27

A=25

A=23

Jones, S. (Keele University) 8–12 M�stars Oct. 2013 11 / 17

Progenitor structures at Z = 0.014

0 1 2 3 4 5 6 7 8 9log10(radius/km)

�10

�5

0

5

10

log10(�

/gcm

�

3)

8.75 M�

8.8 M�

9.5 M�

12 M�

8.8 N87

12.0 WHW

Jones, S. (Keele University) 8–12 M�stars Oct. 2013 12 / 17

Summary

ECSN progenitors from 2 evolutionary paths: well known SAGB and new’failed massive star’.Mass loss still very uncertain for super-AGB phase.3D simulations of stellar regimes are cruicial to constrain boundarybehaviour (e.g. Meakin & Arnett, 2007; Herwig et al., 2011; Mocak et al.,2011).Well resolved grids of weak rates, especially sd-shell nuclei. Coulombcorrections to both the rate and the energy production/loss should beincluded.

I URCA processF 23,25Na, 25,27Mg, 27AlF many other sd-shell nuclei

shell Ye reduction→ contractionF Si-group nuclei

I O-deflagration ignition densityF 24Mg, 24Na, 20Ne, 20F

Jones et al. (2013), ApJ 772, 150

Jones, S. (Keele University) 8–12 M�stars Oct. 2013 13 / 17

Jones et al. (2013), ApJ 772, 150

C

Ne

O

Si

Ne-flash

Si-flame

Ne-flame

URCA

CCSN

CCSN?ECSN

ECSN

ONe WD ONe WDJones, S. (Keele University) 8–12 M�stars Oct. 2013 14 / 17

8.75 and 8.8 M� models - weak interactions8.8 M�: Ye-driven contraction (Ye,min < 0.48)

8.75 M�: Mcore-driven contraction (time for ν-losses)

Jones, S. (Keele University) 8–12 M�stars Oct. 2013 15 / 17

New 20Ne(e−, ν)20F rate

-18

-16

-14

-12

-10

-8

-6

-4

-2

0

9 9.2 9.4 9.6 9.8 10

log 1

0(�

EC[s

-1])

log10 (�Ye [g cm-3])

from Yi Hua LAMT=0.63 GK T=1.00 GK

20Ne (0+) to 20F (2+)(first forbidden)

G. Martinez-Pinedo, Y. H. Lam et al. (in prep.)

Jones, S. (Keele University) 8–12 M�stars Oct. 2013 16 / 17

New SD-shell rates (URCA pairs)

Results for A=25 URCA pair (Toki et al, 2013), USDB

8.0 8.2 8.4 8.6 8.8 9.0

log10(�Ye/g cm�3 )

�30

�25

�20

�15

�10

�5

0

log10(�

/s�

1)

Oda et al. (1994)

Toki and Suzuki (in prep)

25Mg + e− →25Na + νe

8.0 8.2 8.4 8.6 8.8 9.0

log10(�Ye/g cm�3 )

�25

�20

�15

�10

�5

0

log10(�

/s�

1)

Oda et al. (1994)

Toki and Suzuki (in prep)

25Na→25Mg + e− + νe

Jones, S. (Keele University) 8–12 M�stars Oct. 2013 17 / 17