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