Interacting Supernovae

Betelgeuse

Luc Dessart
Institut d’Astrophysique de Paris, CNRS, France

Kervella+09

Why is interaction an efficient engine to boost Lbol?
Ekin (~1051erg) >> time-integrated Lbol (~1049erg) => Tapping 1% of Ekin doubles Erad
Interaction taps regions with largest V, lowest r
Extraction of Ekin depends on M(CSM)/Mej
If M(CSM) >> Mej => Ekin may be totally transformed into Erad

Influence of CSM on shock emergencet106

Envelope

101

Atmosphere/CSM

Eddington factor: fEdd=1/3

fEdd~1

Mean free path: lp << Rtdiff >> tshock

lp ~ R
tdiff ~ tshock

tdiff << tshockRphot

Progenitor t ~ k M/R2 ~ 106-11 -> Big tdiff ~ t DR / c ~ 105-6yr.
Photons trapped until tshock ~ tdiff or t ~ c /vshock ~ few 10
Radiative precursor fainter, broader, redder with CSM
Photon reprocessing in CSM: Narrow line profiles (electron-scattering broadened)
Extra Shock power from interaction with CSM

Lbol boost if CSM not too dense
Need radiative losses to sap EkinMajor difference between CSM at progenitor surface (Ekin ~ Erad) and detached CSM (Ekin >> Erad)Effects associated with Electron-scattering:Frequency redistribution•

photon scattering with free electrons causes frequency redistribution•Non-coherent scattering in CMF caused by the thermal motion of scatterers: Vthermal (~550km/s at 10kK)•Coherent scattering in CMF due to expansion, Redshift in Observer’s frame: Vexpansion•Vexpansion > Vthermal Þ the redshift dominates: P-Cygni profile with enhanced red-wing flux

•Vexpansion < Vthermal Þ non-coherent redshift/blueshift dominates: Symmetric profile (SNe IIn)

Ha

Effect of varying Vphot
on Ha morphology

Interacting Supernovae: Photometry
Huge diversity in both light curves and spectra
Erratic behavior prior to `explosion’
Luminosity boost up to >1010L☉°20

SNe II-Plateau/II-Linear
SN 2005cs
SN 2006qr
SN 2003cn
SN 2007oc
SN 1999em
SN 2012aw°19
MV [mag]

SN 2009ip°18°17

SN 2004et
SN 2013ej
SN 2014G
SN 1979C
SN 1998S°16°15°14 Sample taken from variety ofsources (e.g., Anderson+14)050

100Days since explosion

150

Interacting Supernovae: Photometry

Super-luminous events
Smith+07Light curve diversity
Margutti+14

Late-time flattening

Weil+20

Interacting Supernovae: Spectroscopy
Distinct spectral evolution:
Narrow line profiles early on
broad line profiles later on
And sometimes broad-boxy profiles at very late times

SN1998S

Leonard+00

SN2013fs
Yaron+17

Numerical Simulations of Interacting Supernovae with HERACLES
Application to SN2010jl•

Configuration: Faster inner shell (Ekin) and slower massive outer shell (Mass)•

Multi-group Radiation hydrodynamics with HERACLES (Audit/Gonzalez)•

Application to SLSN IIn 2010jl (Dessart, Audit, Hillier 2015)Super-luminous Type IIn SNe

3Inner shell: SN ejecta
10M¤, 1051erg

Temperature [K]Velocity [km s−1 ]10410310210−1103

10110−1

Radius [1015 cm]

100101Radius [1015 cm]
1210−111010−12Mass [M" ]Density [g cm−1 ]Outer Shell: strong wind
0.1M¤/yr, 3M¤, vel=100km/s
Uniform H-rich composition

100

104

10−1310−1410−1510−168642

10−1710−1

100

10115

Radius [10 cm]

010−1

100

10115

Radius [10 cm]

Figure 2. Initial configuration for the reference interaction model X simulated with HERACLES . We show radial profiles of the velocity, the temperature, themass density, and the Lagrangian mass. Global quantities and additional details for this model are given in Table 1 and Section 2.1.

range), two groups for the Balmer continuum, two for the Paschen
continuum, and three groups for the Brackett continuum and beyond. Our opacity code first computes the LTE level populations

the inner shell (tagged as the SN ejecta, but the results apply to any
ejected shell with similar properties) and the outer shell (we assume
the CSM arises from pre-SN mass loss in the form of a wind). We

Evolution of interaction: Day 4.1

Evolution of interaction: Day 29.9

Evolution of interaction: Day 179.9

Evolution of interaction: Day 389.9

Numerical Simulations of Interacting Supernovae•

Shock powered luminosity:•

Optical depth effects : Lbol<Lshock for t<tdiff•

LC break when shock leaves dense CSM

Lrad @ shocktRCSM/C

SN2010jl model(Fransson et al. 2014)

RCSM/Vshock

Rmax/C
Lrad @ Rmax

Super-luminous Type IIn SNe

13

Spectral evolution: post-processing with CMFGEN
Post-processing with CMFGEN non-monotonic solver
Reproduction of narrow symmetric profiles18 –Very slow spectral– evolution
Evolution to lower T/color (fixed Rphot)
Fransson et al (2014)

SN2010jl
12He IFlux (10−14 erg cm−2 s−1 Å−1)1029d58d

885dd

6119d

176
4448dd531

2614d
847d

0
3500

4000

4500

5000 5500 6000
Rest wavelength (Å)

6500

7000

Fig. 6.— Spectral sequence in the optical from observations with FAST and MMT. Each−1
spectrum has been shifted upwards by 10−14 erg s−1 cm−2 Å relative to the one below.
Figure 11. Montage of spectra at selected epochs (see right label) for our reference model X. The high-frequency patterns in the UV are caused by line
Thewavelengths
oftheBalmerlines
areshown,
aswellasthebroad He I λ5876 line.
blanketing from Fe II and Fe III in this model, while the optical is composed of H I , He I , and Fe II lines. At early times, lines typically show a hybridmorphology with a narrow core and extended wings, up to about 2000 km s−1 from line centre. As time progresses, a blue shifted component, associated withemission from the CDS, grows in strength. Line broadening is then caused by electron scattering and expansion.

14Luc Dessart, Edouard Audit, and D.J. Hillier

Table 2. Summary of properties for the CMFGEN simulations based on the reference interaction model X. We include the properties at the photosphere, at thelocation of maximum density in the interaction region (the CDS), and the properties of the fitted blackbody (see Fig. 13 for an example). We select epochs
when the CDS is well below the photosphere, so that the interaction region is optically thick.

Comparison to SN 2010jlage

Lbol

[d]

[erg s−1 ]MBMV[mag] [mag] [mag] [mag]

20.8
41.7
62.5
83.3
104.2
125.0
145.8

2.15(43)
2.23(43)
1.21(43)
9.88(42)8.65(42)7.99(42)
7.26(42)-18.61-18.84-18.40-18.16-17.95-17.74-17.56-18.68-18.98-18.68-18.55-18.43-18.27-18.12

MR-18.85-19.14-18.90-18.82-18.74-18.62-18.49MI-18.86-19.21-19.03-19.01-18.99-18.89-18.77

Rphot

Tphot

Ne,phot

Rcds

Tcds

Ne,cds

Rbb

Tbb

Lbb

[1015 cm]

[104 K][cm−3 ]

[1015 cm]

[104 K][cm−3 ]

[1015 cm]

[104 K][erg s−1 ]

7.17
7.10
7.02
7.04
7.11
7.08
7.15

1.33
1.27
1.09
1.00
0.97
0.98
1.00

4.36(8)4.42(8)4.05(8)4.00(8)3.94(8)3.96(8)3.90(8)

1.25
1.78
2.86
3.37
3.91
3.64
4.94

1.66
1.18
1.01
0.79
0.76
0.61
0.69

1.76(11)
1.33(11)1.05(11)
3.93(10)2.25(10)9.24(9)9.51(9)

1.172
1.448
1.616
1.848
2.083
2.199
2.199

1.084
1.033
0.879
0.788
0.715
0.673
0.646

2.259(43)2.371(43)1.289(43)1.050(43)9.068(42)8.496(42)7.503(42)

Reproduces narrow line core & broad wings: electron scattering + emission in CSM.
Reproduces (qualitatively) the emission blueshift: Contribution from dense shell!

Figure 12. Montage of multi-epoch spectra for Model X (left) and SN 2010jl (right; Zhang et al. 2012) shown in velocity space with respect to the rest
wavelength of Hα. Qualitatively, the model reproduces well the strengthening of the blue-shifted emission component and the increasing width of the observed
Hα line profile. Quantitatively, the magnitude of the blueshift is somewhat too high while the width of the emission feature is underestimated.

Explosion in confined CSM and SN2013fs
SN2013fs: R(CSM) ~ few R✭, M(CSM) ≪ M(ejecta)
Narrow-core symmetric line profiles for < 1d
High ionization!
Broadening caused by (multiple) scattering with (thermal) free electrons
Broad standard line profiles later on
Simulation from Dessart+17

Ṁ~10-2M¤/yr within 5x1014cm

SN2013fs
Yaron+17

Explosion in extended CSM and SN1998S°20°18°17°150

Simulation from Dessart+16
Ṁ~10-1M¤/yr within 1015cm

SN1998S

SN 2004et
SN 2013ej
SN 2014G
SN 1979C
SN 1998S°16°14

Leonard+00

SN 2005cs
SN 2006qr
SN 2003cn
SN 2007oc
SN 1999em
SN 2012aw°19
MV [mag]

Same as for SN2013fs but R(CSM) ~ many R✭, M(CSM) ≪ M(ejecta)
Narrow-core symmetric line profiles for ~ 10 days
Modest ionization
Strong broad Ha emission at later times
Significant deceleration of outer ejecta (Vmax reduced to ~5000km/s)

50

100Days since explosion

150

Explosion in massive CSM and SN1994W
Different configuration with M(CSM) ≫ M(ejecta)
Narrow line profiles at all times => very different from SN1998S
Fast inner ejecta completely decelerated
Scenario: O/Ne/Si flash ejects envelope followed by core collapse a few years later
Simulation from Dessart+16& core-collapse 2 years later

1049erg pulse

Sollerman+94
Dessart+16

Degeneracy of light curves• Same LC for different CSM (0.05 vs 0.5M☉)
Þ Lower r : Radiative losses & IIn signatures
Þ Higher r: Adiabatic shock & no IIn signatures

PhotosphereComparison of dynamical evolution
Radiative precursor

Dense shell ofswept-up CSM

Lower VmaxNo Radiative precursor

Small/No dense shellHigh Vmax

Results
Interesting variations that indicate:• Survival time of IIn signatures :-> when t_CSM ~ 1• Lbol boost :-> follow Ekin(t), M_cds(t), Vmax(t)• Color of transient :-> Rphot

Peak blueshifts of SN line profiles
Optical depth effect versus dust formation / asymmetry
14

Luc Dessart, Edouard Audit, and D.J. Hillier

Table 2. Summary of properties for the CMFGEN simulations based on the reference interaction model X. We include the properties at the photosphere, at thelocation of maximum density in the interaction region (the CDS), and the properties of the fitted blackbody (see Fig. 13 for an example). We select epochs
when the CDS is well below the photosphere, so that the interaction region is optically thick.
age

Peak blueshift in SNe II
Anderson+14; Dessart & Hillier 2005

LbolMBMV

MRMI

Rphot

Tphot

Ne,phot

Rcds

Tcds

Ne,cds

Rbb

Tbb

Lbb

[d][erg s−1 ] [mag] [mag] [mag] [mag] [1015 cm] [104 K] [cm−3 ] [1015 cm] [104 K] [cm−3 ] [1015 cm] [104 K] [erg s−1 ]

20.8
41.7
62.5
83.3
104.2
125.0
145.8

2.15(43)
2.23(43)
1.21(43)
9.88(42)8.65(42)7.99(42)
7.26(42)-18.61-18.84-18.40-18.16-17.95-17.74-17.56-18.68-18.98-18.68-18.55-18.43-18.27-18.12-18.85-19.14-18.90-18.82-18.74-18.62-18.49-18.86-19.21-19.03-19.01-18.99-18.89-18.77

7.17
7.10
7.02
7.04
7.11
7.08
7.15

1.33
1.27
1.09
1.00
0.97
0.98
1.00

4.36(8)4.42(8)4.05(8)4.00(8)3.94(8)3.96(8)3.90(8)

1.25
1.78
2.86
3.37
3.91
3.64
4.94

1.66
1.18
1.01
0.79
0.76
0.61
0.69

1.76(11)
1.33(11)1.05(11)
3.93(10)2.25(10)9.24(9)9.51(9)

1.172
1.448
1.616
1.848
2.083
2.199
2.199

Peak blueshift in Type IIn SN 2010jl
Dessart+15, Fransson+14, Zhang+12

1.084
1.033
0.879
0.788
0.715
0.673
0.646

2.259(43)2.371(43)1.289(43)1.050(43)9.068(42)8.496(42)7.503(42)Ha
Peak blueshifts in SNe Ia
Blondin+06

Figure 12. Montage of multi-epoch spectra for Model X (left) and SN 2010jl (right; Zhang et al. 2012) shown in velocity space with respect to the rest
wavelength of Hα. Qualitatively, the model reproduces well the strengthening of the blue-shifted emission component and the increasing width of the observed
Hα line profile. Quantitatively, the magnitude of the blueshift is somewhat too high while the width of the emission feature is underestimated.

Type II SNe as metallicity probes
RSG explosion models at different metallicities (Dessart+13)

SLSNe IIn as metallicity probes
More complicated configuration relative to SNe II-P but blanketing effect applies

Conclusions• Physical processes: radiative precursor, mean free path, diffusion time, electronscattering,• Think of origin of line broadening. Where are the photons coming from?
• What mass and energy for inner/outer shells => impacts `vphot(t)’, Lbol(t) etc• Complex line formation: blueshifts can occur in 1D, no dust
• Degeneracy of light curves. Use the information in spectra!