Supernovae Oscar Straniero INAF Oss Astr di Collurania

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

SNe Classification II p H Type II II L SNe I b (strong He) Core collapse of massive stars I c (weak He) o N H Type I I a (strong Si) based on spectra and light curve morphology Thermonuclear explosion

Standard Candles Ø Bright Supernovae Ia Ø Homogeneous Ø No evolutionary effects Thermonuclear Explosion of a CO WD M~MChandrasekhar L ~ 1. 4 M Light Curve 56 Ni time 56 Co 56 Fe L MNi

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

Maximum Brightness - Decline Relation Phillips et al. 1996, 1999 Calibrated locally < > = 0. 17 mag

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

The virial theorem log P Non-degenerate pse a l l co r 4/3 relativistic M 2 M 1 r 5/3 Non-relativistic log r

Massive stars and core collapse Limongi, Straniero & Chieffi, 2001 • e-+p àn+ne (10 Me. V) • 56 Fe+g à 13 a+4 n (124 Me. V)

Evolutionary track of low mass stars PN 0. 6 CO M=1 Mu AGB t=10 Gyr Remnant: CO WD 0. 6 Mu 0. 55 He 0. 2 CO 0. 6 CO HB RGB 0. 1 He WD MS Prada Moroni & Straniero 2002 0. 5 He

Stellar evolution M<0. 8 M¤ t>1/HO 0. 8<M/M¤<8 15 Gyr<t<30 Myr 0. 5<Mf /M¤<1. 1 WD 8<M/M¤<11 t. 10 -30 Myr Mf =1. 2 -1. 3 M¤ WD 11<M/M¤<100 M>100 M¤ t. 1 -10 Myr Mf =1. 2 -2. 5 M¤ (Ye. 0. 45) NS or BH CO ONe. Mg Fe collapse t#1 Myr O (pair jnstability) (Ye=0. 5) may or may not explode

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

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

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

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

Merging scenario: Double degenerate systems: CO+CO a) GWR loss b) secondary tidal disruption c) accretion 10 -5 M yr-1 Too fast accretion

Double Degenerate CO WDs (M=8 H 10 -6 M yr-1) (M=10 -8 M yr-1)

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

Double Degenerate Angular momentum deposition & GWR c) accretion 10 -5 M yr-1 (expansion) d c e f g d) “critical” accretion (contraction) ---- disk ---- WD 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 Piersanti, Gagliardi, Iben & Tornambe’ 2003

Massive stars g e, e+ n, n

Convective regions

At the onset of the core collapse • e-+p àn+ne (10 Me. V) • 56 Fe+g à 13 a+4 n (124 Me. V)

Pressure contributions

COLLAPSE, BOUNCE & STALL Photo-dissociation & neutronization e-+p àn+ne +0. 2 ms -0. 5 ms +2. 0 ms 1012 g/cm 3 3 x 1014 g/cm 3

Neutrino Energy Deposition & Convection: the way trough a successful explosion neutrino energy =1053 erg kinetic + g energy =1051 erg

SN IIp: Light Curves