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Supernovae of Type Ia. Supernovae of Type Ia. Ronald F. Webbink Department of Astronomy University of Illinois. SN 1994D in NGC 4526 (HST). Supernova taxonomy. www.astronomy.com. Hachinger et al. 2006. Cosmological significance. SNe Ia as standard candles - PowerPoint PPT Presentation
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LSU - 25 Oct 07 1
Supernovae of Type Ia
Supernovae of Type Ia
Ronald F. Webbink
Department of Astronomy
University of Illinois
SN 1994D in NGC 4526 (HST)
LSU - 25 Oct 07 2Hachinger et al. 2006
Supernova taxonomy
www.astronomy.com
LSU - 25 Oct 07 3
Cosmological significance
• SNe Ia as standard candles
• Magnitude => Expansion of light sphere with respect to comoving coordinates
• Redshift => Expansion of comoving coordinates
Wood-Vasey, et al. 2007
LSU - 25 Oct 07 4
All SNe Ia are
not the same
www.nd.edu/~kkrisciu
LSU - 25 Oct 07 5
• What is the physical cause of this dispersion?
• Is it truly independent of redshift?
• What secondary factors should affect SN Ia properties?
=> Physics of supernova explosions
• What are their progenitors?
www.nd.edu/~kkrisciu
LSU - 25 Oct 07 6
What do we know?
• Occur in both spiral and elliptical galaxies
Li 2007
LSU - 25 Oct 07 7
What do we know?
• Occur in both spiral and elliptical galaxies
• Rate in spirals correlates with star formation rate (prompt component)
McMillan & Ciardullo 1996
LSU - 25 Oct 07 8
What do we know?
• Occur in both spiral and elliptical galaxies
• Rate in spirals correlates with star formation rate (prompt component)
• Persistent rate among passive (elliptical) galaxies (delayed component)
Sullivan et al. 2006
LSU - 25 Oct 07 9
What do we know?
• Speed correlates with galaxy type
Gallagher et al. 2005
LSU - 25 Oct 07 10
What do we know?
• Speed correlates with galaxy type
• No H, He => MCSM < ~0.03 Msun
Lundqvist 2007
LSU - 25 Oct 07 11
What do we know?
• Speed correlates with galaxy type
• No H, He => MCSM < ~0.03 Msun
• Radio- and X-ray non-detections => dM/dt < ~10-7 Msun yr-1
Panagia, et al. 2006
Hughes et al. 2007
LSU - 25 Oct 07 12
What do we know about the progenitors?• White dwarf progenitors
No H, He
Some SNe Ia from old stellar populations
LSU - 25 Oct 07 13
What do we know about the progenitors?• White dwarf progenitors
No H, He
Some SNe Ia from old stellar
populations
• Thermonuclear runawaySpectra
No compact remnants found
Stehle, et al. 2005
LSU - 25 Oct 07 14
What do we know about the progenitors?• White dwarf progenitors
No H, He
Some SNe Ia from old stellar
populations
• Thermonuclear runawaySpectra
No compact remnants found
• Powered by 56Ni to 56Co
to 56Fe decaySpectra
Light curves Röpke et al. 2007
LSU - 25 Oct 07 15
What do we know about the progenitors?• White dwarf progenitors
No H, He
Some SNe Ia from old stellar populations
• Thermonuclear runawaySpectra
No compact remnants found
• Powered by 56Ni to 56Co to 56Fe decaySpectra
Light curves
• Binary systemsNo other plausible way to trigger instability
LSU - 25 Oct 07 16
Common envelope evolution
Yungelson 2007
LSU - 25 Oct 07 17
Stable mass transfer
Yungelson 2007
LSU - 25 Oct 07 18
SN Ia Progenitors
Yungelson 2007
LSU - 25 Oct 07 19
Candidate Progenitors• Single Degenerates
Cataclysmic VariablesRecurrent NovaeSymbiotic StarsSupersoft X-ray Sources
• Edge-Lit DetonationssdHe/HeWD + CO WD
• Double DegeneratesCO + CO White Dwarfs
LSU - 25 Oct 07 20
Cataclysmic Variables
• Outbursting binaries: Classical Novae (CN)
Dwarf novae (DN)
Novalike variables (NL)
Magnetic CVs (MCV)
• Mwd ~ 0.6-1.0 Msun
• Mdonor < ~2/3 – 1 Msun
• Accretion events (DN,
NL, MCV)
• dM/dt ~ 10-11 – 10-8 Msun yr-1
• Pcrit ~ 1019 dyne cm-2
=> Thermonuclear runaway
LSU - 25 Oct 07 21
Nova ignition masses
Townsley & Bildsten 2005
LSU - 25 Oct 07 22
Gehrz et al. 1998
LSU - 25 Oct 07 23
Classical nova outbursts
• Runaways erode Mwd!
• Many classical novae contain ONeMg white dwarfs
LSU - 25 Oct 07 24
Recurrent Novae
• Mwd close to MCh
• Ejecta lack the heavy-element enhancements characteristic of classical novae => dMwd/dt > 0 ?
• Core composition unknown, but likely to be ONeMg white dwarfs (cf. CN)
• Rare: Death rate ~ 10-2 SN Ia rate
LSU - 25 Oct 07 25
Symbiotic Stars
• Heterogenous class of objects, mostly wind-accreting WD companions to luminous M giants or AGB stars
• Hot components mostly powered by H burning on white dwarf
• Mwd mostly unknown, but those in T CrB, RS Oph (erstwhile RNe) must be near MCh
• Extremely H-rich environment
LSU - 25 Oct 07 26Munari & Zwitter 2002
LSU - 25 Oct 07 27
Supersoft X-ray Sources
• Heterogeneous class of objects (incl. PNNe, SNR, Symbiotic Stars), but many are stable H-burning white dwarfs
Nomoto et al. 2007
LSU - 25 Oct 07 28
Supersoft X-ray Sources
• Heterogeneous class of objects (incl. PNNe, SNR, Symbiotic Stars), but many are stable H-burning white dwarfs
• Population synthesis predicts ~103 SSS in M31 if SN Ia progenitors
LSU - 25 Oct 07 29
SSS in M31
center disk
Di Stefano 2007
LSU - 25 Oct 07 30
Supersoft X-ray Sources
• Heterogeneous class of objects (incl. PNNe, SNR, Symbiotic Stars), but many are stable H-burning white dwarfs
• Population synthesis predicts ~103 SSS in M31 if SN Ia progenitors => 102 times number seen in X-rays
• Can they be hidden?
LSU - 25 Oct 07 31
Evolution of SSS
Di Stefano & Nelson 1996
LSU - 25 Oct 07 32
Supersoft X-ray Sources• Can they be hidden?
• Perhaps super-Eddington luminosity (accretion + burning) drives a massive stellar wind
Hachisu & Kato 2003
LSU - 25 Oct 07 33
Supersoft X-ray Sources• Can they be hidden?
• Perhaps super-Eddington luminosity (accretion + burning) drives a massive stellar wind
• BUT such a model predicts– H, He-rich ejecta
– Relatively dense stellar wind
both in violation of observational limits
LSU - 25 Oct 07 34
Supersoft X-ray Sources• Can they be hidden?
• Perhaps super-Eddington luminosity (accretion + burning) drives a massive stellar wind
• BUT such a model predicts– H, He-rich ejecta
– Relatively dense stellar wind
both in violation of observational limits
• Alternative: Super-Eddington accretion regenerates AGB giant
LSU - 25 Oct 07 35
Supersoft X-ray Sources• Can they be hidden?
• Perhaps super-Eddington luminosity (accretion + burning) drives a massive stellar wind
• BUT such a model predicts– H, He-rich ejecta
– Relatively dense stellar wind
both in violation of observational limits
• Alternative: Super-Eddington accretion regenerates AGB giant
• Maximum lifetime to carbon ignition (delay to SN Ia) ~ 1.6 X 109 yr
LSU - 25 Oct 07 36
Problems withSingle-Degenerate Progenitors
• Instability of He-burning shell
LSU - 25 Oct 07 37
Thermal pulses in AGB stars
Iben & Renzini 1983
LSU - 25 Oct 07 38
Thermal pulses in accreting white dwarfs
Cassisi, Iben & Tornambè 1998
LSU - 25 Oct 07 39
Problems withSingle-Degenerate Progenitors
• Instability of He-burning shell– What of Surface Hydrogen Burning?
LSU - 25 Oct 07 40
Surface Hydrogen Burning
Starrfield 2007
LSU - 25 Oct 07 41
Surface Hydrogen Burning
LSU - 25 Oct 07 42
Problems withSingle-Degenerate Progenitors
• Instability of He-burning shell• Ablation of H-rich donor in supernova event
LSU - 25 Oct 07 43
Marietta, Burrows & Fryxell 2000
LSU - 25 Oct 07 44
LSU - 25 Oct 07 45
Problems withSingle-Degenerate Progenitors
• Instability of He-burning shell• Ablation of H-rich donor in supernova event• Surviving companion?
LSU - 25 Oct 07 46
Companion peculiar velocities
Canal, Méndez & Ruiz-Lapuente 2001
LSU - 25 Oct 07 47
Tycho (SN1572) Companion?
Ruiz-Lapuente, et al. 2004
LSU - 25 Oct 07 48
Companion Rotation Velocities
Schmidt 2007
LSU - 25 Oct 07 49
Tycho G revisited
Schmidt 2007
LSU - 25 Oct 07 50
Edge-Lit Detonations• Degenerate ignition of ~0.1 Msun of He on ~1 Msun
CO white dwarf can trigger double detonation• Mass transfer too rapid from non-degenerate He
star donor to permit accreted envelope to cool to degeneracy and develop strong flashes
• Degenerate donors have even higher mass transfer rates until Mdonor < ~0.05 Msun
• Degenerate He ignition produces outward-propagating detonation, but fails to detonate CO core, or to produce intermediate-mass elements (e.g., Si) seen at maximum light
LSU - 25 Oct 07 51
Failed Double Detonation
Bildsten 2007
LSU - 25 Oct 07 52
CO +CO White Dwarf Mergers
• Wide range of delay times from GR inspiral
Yungelson 2007
LSU - 25 Oct 07 53
CO +CO White Dwarf Mergers
• Wide range of delay times from GR inspiral
• Eddington-limited accretion ignites carbon at the base of the accreted envelope (1D)
Nomoto & Iben 1985
LSU - 25 Oct 07 54
CO +CO White Dwarf Mergers
• Wide range of delay times from GR inspiral
• Eddington-limited accretion ignites carbon at the base of the accreted envelope (1D)
• But mass transfer occurs on a dynamical time scale
LSU - 25 Oct 07 55
White dwarf coalescence
Yoon, Podsiadlowski & Rosswog 2007
LSU - 25 Oct 07 56
Merged Double White Dwarf
Yoon, Podsiadlowski & Rosswog 2007
LSU - 25 Oct 07 57
CO +CO White Dwarf Mergers
• Wide range of delay times from GR inspiral
• Eddington-limited accretion ignites carbon at the base of the accreted envelope (1D)
• But mass transfer occurs on a dynamical time scale
• Carbon ignition quenched in 2D or 3D by meridional expansion
LSU - 25 Oct 07 58
Problems withDouble-Degenerate Progenitors
• Tidal synchronization and preheating during approach to merger
Iben, Tutukov & Fedorova 1998
LSU - 25 Oct 07 59
Problems withDouble-Degenerate Progenitors
• Tidal synchronization and preheating during approach to merger
• Angular momentum transport
LSU - 25 Oct 07 60
Synchronization at low accretion rates
• KH – Kelvin-Helmholtz instability
• BC – Baroclinic instability
• TS – Tayler-Spruit dynamo
Piro 2007
LSU - 25 Oct 07 61
Problems withDouble-Degenerate Progenitors
• Tidal synchronization and preheating during approach to merger
• Angular momentum transport
• Shock heating of accreted matter and the site of carbon ignition
=> Neutrino cooling of accreted envelope?
LSU - 25 Oct 07 62
Are there enough double-degenerates?
Napiwotzki 2007
LSU - 25 Oct 07 63
Theoretical DD Search Yields
LSU - 25 Oct 07 64
SN Ia ProgenitorComparative Yields
Yungelson 2007
LSU - 25 Oct 07 65
The Parting Shot:We’re looking for haystacks, not needles!
Maoz 2007