Modelling thermonuclear supernovae Stuart Sim Mattia Bulla, Mark - - PowerPoint PPT Presentation

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Modelling thermonuclear supernovae Stuart Sim Mattia Bulla, Mark - - PowerPoint PPT Presentation

Nov 08, 2022 169 likes •508 views

Modelling thermonuclear supernovae Stuart Sim Mattia Bulla, Mark Magee, Markus Kromer, Fritz Rpke, Ashley Ruiter, Ivo Seitenzahl, Wolfgang Hillebrandt Supernovae in astrophysics Explosive death of star dramatic end point of stellar

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Mattia Bulla, Mark Magee, Markus Kromer, Fritz Röpke, Ashley Ruiter, Ivo Seitenzahl, Wolfgang Hillebrandt

Stuart Sim

Modelling thermonuclear supernovae

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  • Explosive death of star – dramatic end point of stellar evolution
  • Nuclear burning in SNe makes the heavy elements
  • Inject energy, momentum and metals; can affect galaxy evolution
  • Type Ia “Standardizable candles”, probes of expansion history of the Universe
  • Challenge our understanding of physics

– Turbulence and hydrodynamics – Combustion and flame physics – Nuclear physics – Radiative transfer

Melbourne 2017

Supernovae in astrophysics

SN1994D in NGC 4526 NASA/HST

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  • Thermonuclear supernovae

– Reminder of basic picture for Type Ia supernovae

  • Explosion models

– Chandrasekhar mass explosions

  • Pure deflagrations and SNe Iax (Magee)

– Sub-Chandrasekhar mass models

Melbourne 2017

Overview

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Melbourne 2017

CO WD

56Ni

IMEs

56Ni 56Ni

  • > 56Co
  • > 56Fe

Ignition, birth of flame Flame propagation Energy release by flame unbinds star ~2 sec. Ejecta expand; homologous by ~100 sec. Radioactive decays reheat ejecta Peak of

  • ptical display

as energy from radioactivity escapes ~20 days

Established picture for a thermonuclear supernova explosion

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Supernovae Ia

~0.7 M¤ of

56Ni is typical

Melbourne 2017

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Made of Si, S and Fe Velocities measured from lines

Supernovae Ia

km/s 000 , 15 ~ v

H and He not detected

Melbourne 2017

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Melbourne 2017

Supernovae Ia: diversity

(rates from Li et al. 2011) Diversity in SNe Ia and related transients (figure from Taubenberger 2017)

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Melbourne 2017

Supernovae Ia

Li et al. 2011 (Lick Obs. SN. Search)

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Melbourne 2017

Thermonuclear Supernovae

Many unanswered questions remain:

  • How did the system evolve to ignition?
  • Progenitor channel debate (“single vs double degenerate”)
  • What are the properties of the exploding

star and how do these affect what we see?

  • Mass of WD, composition, immediate environment?
  • Where does the flame ignite and how does it

propagate (deflagration, detonation)?

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Melbourne 2017

SN Ia Flame Basics

  • Instantaneously narrow region in which

nuclear reactions are taking place

  • Thermonuclear flame propagation modes
  • Deflagration (sub-sonic)
  • Detonation (supersonic)
  • Flame generates energy (nuclear burning)
  • Eventually unbinds star
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Melbourne 2017

Synthetic explosions:

testing models by comparing to data

Theories for progenitor(s) Spectra / photometry for SN Ia Ignition conditions Composition structure Explosion conditions and final state Hydrodynamical simulations Nucleosynthesis calculations Radiative transfer simulations Parameterised

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Melbourne 2017

Testing explosion scenarios

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Melbourne 2017

Explosion scenarios

Best known paradigm:

(Near-)Chandrasekhar-mass single-degenerate scenario

– WD in binary with H-rich star (main-sequence or giant) – Mass-transfer – Mass is retained (avoid net mass- loss in nova explosions) – H burned to He then C/O – WD grows in mass: central density and temperature rise

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Melbourne 2017

Explosion scenarios

Best known paradigm:

(Near-)Chandrasekhar-mass single-degenerate scenario

Explosion mechanism:

– WD heated by C burning during ~1000 yr “simmering” phase (Kuhlen et al. 06, Zingale et al. 06, 11) – Thermonuclear runaway occurs – Deflagration born (prompt detonation is no good for Ch mass) – Proceeds as pure deflagration?

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Deflagration models

3D simulation: Kromer+ 13

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Deflagration models

Sequence of models: Fink+14. – roughly 1 order of magnitude in 56Ni mass. Bound remnant found in some cases, in agreement with Jordan+12. 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 Enuc (1051 erg) 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 ejected mass (M) Mtot MIGE M56Ni MIME 1 3 5 10 20 40

100L 100 100H 1600C 300C 1600 200 150

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Melbourne 2017

Supernovae Ia: diversity

Multiple sub-classes of SNe Ia / related transients (figure from Taubenberger 2017)

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There are now multiple sub-classes of SNe Ia (from Li et al. 2011)

Melbourne 2017

Supernovae Ia: diversity

Faint and fast Bright with early IGE lines Faint with weak IMEs Also a sample of very bright cases e.g.

2003fg (Howell+); 2007if (Scalzo+, Yuan+); 2009dc (Yamanaka+)... And a handful of faint, slowly evolving cases PTF10ops (Maguire+); 2010lp (Pignata+)

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Pure deflagration: 02cx-like SNe?

Pure deflagration models: Suggested connection to peculiar (faint) Ia’s: Branch+04, Jha+06, Phillips+07 Now evidence that 02cx-like class (“SNe Iax”; Foley+09,13)

  • is large and diverse
  • range of ejecta mass

(“failed” deflagrations) Foley+ 13

20 40 60 Rest−Frame Days Relative to V Maximum −12 −13 −14 −15 −16 −17 −18 Absolute V Magnitude

08ha 09J 05cc 03gq 02cx 08ae 08ge 05hk 08A 12Z 11ay

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First plausible detection of a Ia progenitor: (from McCully et al. 2014)

Melbourne 2017

Supernovae Ia: a progenitor?

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Deflagration models

Spectra of 05hk from Phillips+07

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Deflagration models

Spectra of 05hk from Phillips+07 - pretty good match to model (Kromer+ 13)

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Deflagration models

N5 compared to 05hk – late times?

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Deflagration models

Comparison extended to fainter example: SN2015H Magee+2016

15 16 17 18 19 20 57040 57060 57080 57100 57120 57140 57160 57180 57200 57220

  • 20

20 40 60 80 100 120 140 Apparent Magnitude MJD Days since maximum g + 1 V + 0.5 r i - 0.5 J - 1 H - 1.5 K - 2

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Deflagration models

Comparison extended to fainter example: SN2015H Magee+2016

  • 20
  • 19
  • 18
  • 17
  • 16
  • 15
  • 14

0.2 0.4 0.6 0.8 1 1.2 1.4

15H 05hk 08A 08ae 09ku 11ay 12Z 10ae 08ha 09J 05cc 03gq 02cx 09ego 09eoi 11hyh 04cs PS15csd 07qd Normal Ia N5def N3def N1def SNe Iax r R Normal SNe Ia Model

Peak Absolute Magnitude Decline Rate

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Deflagration models

SN2015H Magee+2016

  • 19
  • 18
  • 17
  • 16
  • 15
  • 14

g Absolute Magnitude V N5def N3def N1def

  • 18
  • 17
  • 16
  • 15
  • 14

5 15 25 35 45 r Days since explosion 5 15 25 35 45 i

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Deflagration models

SN2015H

Magee+2016 (22 days)

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Deflagration models: summary

Strengths:

  • Full star, multi-D deflagration simulations – explosions occur
  • Star not (always) full disrupted
  • Synthetic spectra are fair matches to observed SN Iax class
  • Peak luminosities (and colours) match fairly well
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Deflagration models: summary

Strengths:

  • Full star, multi-D deflagration simulations – explosions occur
  • Star not (always) full disrupted
  • Synthetic spectra are fair matches to observed SN Iax class
  • Peak luminosities (and colours) match fairly well

Open issues:

  • Light curve timescales too fast in models: need more ejecta mass?
  • Support for alternative models (e.g. PDD models; Stritzinger et al. 2015)
  • Major challenge: late times
  • Major challenge: very faint objects (08ha needs only ~3x10-3 Msunof 56Ni)
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Deflagration model: late evolution

Comparison of bolometric light curve

  • ut to late times

(Kromer+13) Energy deposited in the “bound” remnant? Jha+06, Sahu+08, Foley+16, Shen+17

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Deflagration models

Comparison extended to fainter example:

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  • 19
  • 18
  • 17
  • 16
  • 15
  • 14

0.2 0.4 0.6 0.8 1 1.2 1.4

15H 05hk 08A 08ae 09ku 11ay 12Z 10ae 08ha 09J 05cc 03gq 02cx 09ego 09eoi 11hyh 04cs PS15csd 07qd Normal Ia N5def N3def N1def SNe Iax r R Normal SNe Ia Model

Peak Absolute Magnitude Decline Rate

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Deflagration models

Conclusion:

(Jordan et al. 2012; Kromer et al. 2013, Fink et al. 2014, Kromer et al. 2015, Magee et al. 2016)

Near-Chandrasekhar mass WD deflagrations may work well for the 2002cx-like SNe Ia

…still multiple loose ends …what are the “normal” ones?!