Post on 28-Nov-2021
Abigail Polin NSF Fellow, UC Berkeley
12 March 2019
Cooks Branch Workshop 12 March 2019abigail@bekeley.edu
Modeling Sub-Chandrasekhar Mass White Dwarf Explosionsas Type Ia Supernovae
The Sub-Chandrasekhar Model
C/O WD
M < 1.4 M⦿ surface Helium shell
Double Detonation Scenario: detonation of the surface helium leads to a detonation of the carbon-oxygen core
accreted from
from a collision with
non-degenerate
degenerate
He WD
(Thick Helium Shells)
(Thin Helium Shells)
Primary Progenitor
Possible Companion
Cooks Branch Workshop 12 March 2019
Numerical Methods — CastroCastro: an adaptive mesh, astrophysical radiation hydrodynamics code
example adaptive grid designed to tag areas of nuclear burning for refinement
Radius (km)
Tem
pera
ture
(K)
Den
sity
(g/c
m3 )
Cooks Branch Workshop 12 March 2019
Double Detonation - 0.76 M⦿ WD w/ 0.15 M⦿ HeDensityTemperature
Cooks Branch Workshop 12 March 2019
Potential for heavy elenents in the outer ejecta
Density radioactive elements IMEs (10<Z<40)
Cooks Branch Workshop 12 March 2019
Example Ejecta Composition
0.01
0.1
1
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1
5 x 103 km/s 10 15 2025M
ass
Frac
tion
Interior Mass [MO• ]
4He16O10 < Z ≤ 2044Ti+48Cr+52Fe56Ni
1.0 M⦿ WD w/ 0.08 M⦿ He
Cooks Branch Workshop 12 March 2019
Light Curves - (g-band)
0 5 10 15 20 25 30 35 40 45
0.08 MO• He Shells
Days Since Explosion
1.1 MO• WD1.0 MO• WD0.9 MO• WD0.8 MO• WD
-20
-19
-18
-17
-16
-15
-14
-13
-12 0 5 10 15 20 25 30 35 40 45
0.01 MO• He Shells
Abso
lute
Mag
nitu
de
Days Since Explosion
1.1 MO• WD1.0 MO• WD0.9 MO• WD0.8 MO• WD
Thin Helium Shells Thick Helium Shells
Cooks Branch Workshop 12 March 2019
Spectra - (at peak g-band)Thin Helium Shells Thick Helium Shells
3000 4000 5000 6000 7000 8000 9000 10000
1.1
1.0
0.9
0.8
0.85
0.7
CaII
SiII CaII
TiII
1.2
log
F ν in
arb
itrar
y un
its
Wavelength (Angstroms)
1.1 MO•
1.0 MO•
0.9 MO•0.8 MO•0.7 MO•
CaII SiII CaIITiII
Spectra at Peak
F λ in
arb
itrar
y un
its3000 4000 5000 6000 7000 8000 9000
0.8 MO• WD2.6 days after explosion
Spectra at Early Excess
Wavelength (Angstroms)
Cooks Branch Workshop 12 March 2019
Thin Helium Shells Thick Helium Shells
3000 4000 5000 6000 7000 8000 9000 10000
1.1
1.0
0.9
0.8
0.85
0.7
CaII
SiII CaII
TiII
1.2
log
F ν in
arb
itrar
y un
its
Wavelength (Angstroms)
1.1 MO•
1.0 MO•
0.9 MO•0.8 MO•0.7 MO•
CaII SiII CaIITiII
Spectra at Peak
F λ in
arb
itrar
y un
its3000 4000 5000 6000 7000 8000 9000
0.8 MO• WD2.6 days after explosion
Spectra at Early Excess
Wavelength (Angstroms)
Spectra - (at peak g-band)
Cooks Branch Workshop 12 March 2019
Thin Shells - Peak Spectra - 0.01 M⦿ He
3000 4000 5000 6000 7000 8000 9000 10000
1.1
1.0
0.9
0.8
0.85
0.7
CaII
SiII CaII
TiII
1.2
log
F ν in
arb
itrar
y un
its
Wavelength (Angstroms)
Cooks Branch Workshop 12 March 2019
Thin Shells — 0.01 M⦿ He
3000 4000 5000 6000 7000 8000 9000 10000
log
F ν in
arb
itrar
y un
its
Wavelength (Angstroms)
0.8 MO• WD0.85 MO• WD
0.9 MO• WD1991bg
Cooks Branch Workshop 12 March 2019
Thin Shells — 0.01 M⦿ He
3000 4000 5000 6000 7000 8000 9000 10000
1.1
1.0
0.9
0.8
0.85
0.7
CaII
SiII CaII
TiII
1.2
log
F ν in
arb
itrar
y un
its
Wavelength (Angstroms)
Cooks Branch Workshop 12 March 2019
Thin Shells — 0.01 M⦿ HeLu
min
osity
(WD
Mas
s)
3000 4000 5000 6000 7000 8000 9000 10000
1.1
1.0
0.9
0.8
0.85
0.7
CaII
SiII CaII
TiII
1.2
log
F ν in
arb
itrar
y un
its
Wavelength (Angstroms)
Cooks Branch Workshop 12 March 2019
Thin Shells — 0.01 M⦿ HeLu
min
osity
(WD
Mas
s)
3000 4000 5000 6000 7000 8000 9000 10000
1.1
1.0
0.9
0.8
0.85
0.7
CaII
SiII CaII
TiII
1.2
log
F ν in
arb
itrar
y un
its
Wavelength (Angstroms)
Si II Velocity
Cooks Branch Workshop 12 March 2019
Thin Shells — 0.01 M⦿ He
-20.5
-20.0
-19.5
-19.0
-18.5
-18.0
-17.5
-17.09.0 10.0 11.0 12.0 13.0 14.0 15.0 16.0
MB
SiII Velocity [1000 km/s]
Zheng et al. 2018
Polin et al. 2018
Cooks Branch Workshop 12 March 2019
Thin Shells — 0.01 M⦿ He
-20.5
-20.0
-19.5
-19.0
-18.5
-18.0
-17.5
-17.09.0 10.0 11.0 12.0 13.0 14.0 15.0 16.0
MB
SiII Velocity [1000 km/s]
Zheng et al. 2018
-20.5
-20.0
-19.5
-19.0
-18.5
-18.0
-17.5
-17.09.0 10.0 11.0 12.0 13.0 14.0 15.0 16.0
1.10 MO• WD1.00 MO• WD0.90 MO• WD
1.20 MO• WD
MB
SiII Velocity [1000 km/s]
0.01 MO• He ShellsZheng et al. 2018
-20.5
-20.0
-19.5
-19.0
-18.5
-18.0
-17.5
-17.09.0 10.0 11.0 12.0 13.0 14.0 15.0 16.0
1.10 MO• WD1.00 MO• WD0.90 MO• WD
1.20 MO• WD
MB
SiII Velocity [1000 km/s]
-20.5
-20.0
-19.5
-19.0
-18.5
-18.0
-17.5
-17.09.0 10.0 11.0 12.0 13.0 14.0 15.0 16.0
1.10 MO• WD1.00 MO• WD0.90 MO• WD
1.20 MO• WD
MB
SiII Velocity [1000 km/s]
-20.5
-20.0
-19.5
-19.0
-18.5
-18.0
-17.5
-17.09.0 10.0 11.0 12.0 13.0 14.0 15.0 16.0
1.10 MO• WD1.00 MO• WD0.90 MO• WD
1.20 MO• WD
MB
SiII Velocity [1000 km/s]
-20.5
-20.0
-19.5
-19.0
-18.5
-18.0
-17.5
-17.09.0 10.0 11.0 12.0 13.0 14.0 15.0 16.0
1.10 MO• WD1.00 MO• WD0.90 MO• WD
1.20 MO• WD
MB
SiII Velocity [1000 km/s]
-20.5
-20.0
-19.5
-19.0
-18.5
-18.0
-17.5
-17.09.0 10.0 11.0 12.0 13.0 14.0 15.0 16.0
1.10 MO• WD1.00 MO• WD0.90 MO• WD
1.20 MO• WD
MB
SiII Velocity [1000 km/s]Polin et al. 2018
Cooks Branch Workshop 12 March 2019
Thin Shells — 0.01 M⦿ He
-20.5
-20.0
-19.5
-19.0
-18.5
-18.0
-17.5
-17.09.0 10.0 11.0 12.0 13.0 14.0 15.0 16.0
MB
SiII Velocity [1000 km/s]
Zheng et al. 2018
-20.5
-20.0
-19.5
-19.0
-18.5
-18.0
-17.5
-17.09.0 10.0 11.0 12.0 13.0 14.0 15.0 16.0
MB
SiII Velocity [1000 km/s]
0.01 MO• He ShellsZheng et al. 2018
-20.5
-20.0
-19.5
-19.0
-18.5
-18.0
-17.5
-17.09.0 10.0 11.0 12.0 13.0 14.0 15.0 16.0
MB
SiII Velocity [1000 km/s]
-21.0
-20.5
-20.0
-19.5
-19.0
-18.5
-18.0
-17.5
-17.09.0 10.0 11.0 12.0 13.0 14.0 15.0 16.0
MB
SiII Velocity [1000 km/s]
0.01 MO• He ShellsZheng et al. 2018
-0.4 -0.3 -0.2 -0.1 0.0 0.1 0.2 0.3 0.4B-V
-21.0
-20.5
-20.0
-19.5
-19.0
-18.5
-18.0
-17.5
-17.09.0 10.0 11.0 12.0 13.0 14.0 15.0 16.0
MB
SiII Velocity [1000 km/s]
-0.4 -0.3 -0.2 -0.1 0.0 0.1 0.2 0.3 0.4B-V
Polin et al. 2018
Cooks Branch Workshop 12 March 2019
Thin Helium Shells Thick Helium Shells
3000 4000 5000 6000 7000 8000 9000 10000
1.1
1.0
0.9
0.8
0.85
0.7
CaII
SiII CaII
TiII
1.2
log
F ν in
arb
itrar
y un
its
Wavelength (Angstroms)
1.1 MO•
1.0 MO•
0.9 MO•0.8 MO•0.7 MO•
CaII SiII CaIITiII
Spectra at Peak
F λ in
arb
itrar
y un
its3000 4000 5000 6000 7000 8000 9000
0.8 MO• WD2.6 days after explosion
Spectra at Early Excess
Wavelength (Angstroms)
Spectra - (at peak g-band)
Cooks Branch Workshop 12 March 2019
Thick Shells — 0.08 M⦿ He
1.1 MO•
1.0 MO•
0.9 MO•0.8 MO•0.7 MO•
CaII SiII CaIITiII
Spectra at PeakF λ
in a
rbitr
ary
units
3000 4000 5000 6000 7000 8000 9000
0.8 MO• WD2.6 days after explosion
Spectra at Early Excess
Wavelength (Angstroms)
Cooks Branch Workshop 12 March 2019
SN2018byg (ZTF18aaqeasu)A Massive Helium-shell Double Detonation on a Sub-Chandrasekhar Mass White Dwarf De et al. 2019
�20 �10 0 10 20 30 40Rest frame phase from r band peak (days)
18
19
20
21
22
App
aren
tm
agni
tude
�19
�18
�17
�16
�15
Abs
olut
em
agni
tude
S S S S S S S S
P48 r
P60 r
P60 g � 3
P200 g � 3
P60 i + 1.5
Cooks Branch Workshop 12 March 2019
SN2018byg (ZTF18aaqeasu)
De et al. 2019
0 10 20 30 40Rest frame time from explosion (days)
�19.5
�19.0
�18.5
�18.0
�17.5
�17.0
�16.5
Abs
olut
em
agni
tude
K10 0.81 M�, 0.13 M�
K10 0.92 M�, 0.08 M�
P18 0.80 M�, 0.15 M� NM
P18 0.76 M�, 0.15 M� NM
P18 0.76 M�, 0.15 M�, 0.2 M�
P18 0.7 M�, 0.15 M�, NM
P18 0.8 M�, 0.08 M�, NM
ZTF 18aaqeasu
Cooks Branch Workshop 12 March 2019
SN2018byg (ZTF18aaqeasu)0.76 M⦿ WD w/ 0.15 M⦿ Shell
De et al. 2019
no mixing0.18 M⦿ mixing
Cooks Branch Workshop 12 March 2019
SN2018byg (ZTF18aaqeasu)0.76 M⦿ WD w/ 0.15 M⦿ Shell
De et al. 2019
no mixing0.18 M⦿ mixing
Σ (Xradioactive)
Cooks Branch Workshop 12 March 2019
Future/Preliminary WorkNebular Modeling
2000 4000 6000 8000 10000 12000
Day 150
1.2 MO• WD 1.1 MO• WD1.0 MO• WD 0.9 MO• WD
0.85 MO• WD 0.8 MO• WD
F λ in
arb
itrar
y un
its
Wavelength [°A]
0.01 M⦿ He Shells
Cooks Branch Workshop 12 March 2019