Supernovae Oscar Straniero INAF – Oss. Astr. di Collurania (TE)

SNe Classification Core collapse of massive stars Thermonuclear explosion I b (strong He) I c (weak He) SNe II p Type II II L No H H Type I I a (strong Si) based on spectra and light curve morphology

Standard Candles  Bright  Homogeneous  No evolutionary effects Supernovae Ia Light Curve L time 56 Ni  56 Co  56 Fe Thermonuclear Explosion of a CO WD M~M Chandrasekhar  L  M Ni ~ 1.4 M 

Observed Relations Riess et al., 1997 Brighter Slower Decline Dimmer Faster Decline

Calibrated locally Phillips et al. 1996, 1999 = 0.17 mag Maximum Brightness - Decline Relation

…… bombs often fail. Similarly, most models for astrophysical bombs (Sne Ia) often fail. The conceptually simplest model for a thermonuclear supernova is just an analog of a runaway chemical reaction that become explosive : a conventional bomb. …… Further, astrophysical bombs must occur naturally and at the correct rate: there must be a convincing astronomical context.

log  log P  5/3  4/3 M1M1 M2M2 Non-degenerate Non-relativistic relativistic collapse The virial theorem

Massive stars and core collapse e - +p  n+ e (10 MeV) 56 Fe+   13  +4n (124 MeV) Limongi, Straniero & Chieffi, 2001

Evolutionary track of low mass stars 0.6 CO 0.55 He 0.2 CO 0.1 He 0.5 He 0.6 CO WD MS RGBHB AGB PN M=1 M u  =10 Gyr Remnant: CO WD 0.6 M u Prada Moroni & Straniero 2002

Stellar evolution M<0.8 M  0.8<M/M  <8 8<M/M  <11 11<M/M  <100 M>100 M   Gyr  Myr 0.5<M f /M  <1.1 CO WD   .  Myr M f = M  ONeMg WD .  1-10 Myr M f = M  Fe (Y e. 0.45) collapse NS or BH  #1  Myr O (pair jnstability) (Y e =0.5) may or may not explode

Astrophysical Explosive Devices Gravitational collapse Induced Core collapse (nuclear runaway fails) Pair instability, core collapse & O explosion (core collapse fails) C-deflagration C or He detonation C-delayed detonation Thermonuclear SNe RG WD

Nucleosynthesis in Thermonuclear SNe He-detonation C-delayed detonation C-deflagration

SNe Ia Light Curves: mass and metallicity effects Domínguez, Hoflich, Straniero 2001

Most of the accreted material is lost during the H-pulse: too long time H accreting WDs RG MS

Merging scenario: Double degenerate systems: CO+CO a) GWR loss b) secondary tidal disruption c) accretion M  yr -1 Too fast accretion

(M=8 H M  yr -1 ) Double Degenerate CO WDs (M=10 -8 M  yr -1 )

Single Degenerate. Massive WDs: the lifting effect of rotation H He CO Dominguez, Straniero, Isern & Tornambe’ 1996

Double Degenerate Angular momentum deposition & GWR c) accretion M  yr -1 (expansion) d) “critical” accretion (contraction) e) tri-axial configuration and energy loss via GWR f) balance between ang. mom. deposition and energy loss (steady accretion) g) Viscous dissipation and explosion d c e f g ---- disk ---- WD Piersanti, Gagliardi, Iben & Tornambe’ 2003

Massive stars  e,e + 

Convective regions

At the onset of the core collapse e - +p  n+ e (10 MeV) 56 Fe+   13  +4n (124 MeV)

Pressure contributions

COLLAPSE, BOUNCE & STALL +0.2 ms -0.5 ms +2.0 ms g/cm 3 3x10 14 g/cm 3 Photo-dissociation & neutronization e - +p  n+ e

Neutrino Energy Deposition & Convection: the way trough a successful explosion neutrino energy =10 53 erg kinetic +  energy =10 51 erg

SN IIp: Light Curves