Type Ia Supernovae Progenitors Luciano Piersanti INAF Osservatorio

Type Ia Supernovae Progenitors Luciano Piersanti INAF – Osservatorio Astronomico di Teramo INFN – Sezione di Perugia Portopalo (Si), 11 -16 June 2017 THE FOURTH AZARQUIEL SCHOOL OF ASTRONOMY

SUPERNOVAE: AN INTRODUCTION During SNe explosion very complex physical processes are at work from the explosion mechanism to nucleosynthesis, radiation transport and shock physics. (Leibundgut 2000) Supernovae (SNe) represents the final explosive outcomes of stars which succeed in synthesizing heavy elements (Z>12) A large part of the progenitor (for SNe Ia the whole star) is ejected, thus polluting the interstellar medium. Supernovae allow to explain the observed metallicity gradient. During the explosion a large amount of energy is delivered (for SNe Ia ~1051 erg). Supernovae are very luminous objects Portopalo (SI), 11 -16 June 2017 THE FOURTH AZARQUIEL SCHOOL OF ASTRONOMY

SUPERNOVAE: AN INTRODUCTION SNe Ia represent a very homogeneous class of events. They can be used as standardized candles on cosmological distance CURRENTLY THE UNIVERSE IS EXPANDING AT AN ACCELERATED RATE, WHILE IT WAS NOT IN THE PAST NOBEL PRIZE FOR PHYSICS 2011 A. Riess Portopalo (Si), 11 -16 June 2017 B. Schmidt S. Perlmutter THE FOURTH AZARQUIEL SCHOOL OF ASTRONOMY

SUPERNOVAE: AN INTRODUCTION CLASSIFICATION (Minkowsky, 1940 & 1941) SUPERNOVAE: PHENOMENA MORE LUMINOUS THAN THEIR OWN PARENT GALAXY (Lundmark 1920) PROPERTIES Type I Supernovae Type II Supernovae Presence of Balmer lines in the optical spectrum NO YES Related to H II region NO YES SNe Ia SNe Ib SNe Ic SNe II L SNe II P Absortion line at l=6150Å No lines at l=6150Å Strong line at l=5876Å No lines at l=6150Å and l=5876Å Large plateau after maximum Linear decline after maximum Portopalo (Si), 11 -16 June 2017 THE FOURTH AZARQUIEL SCHOOL OF ASTRONOMY

SUPERNOVAE: AN INTRODUCTION Frequency of Explosion 1 SNu (Supernova Unit): One SN per 100 yr in a galaxy with LB=1010 Lʘ Supernova Type Frequency (SNu) % SNe Ia 0. 28 h 2 18% SNe Ib/c 0. 27 h 2 17% SNe II 1. 04 h 2 65% Galaxy Type Branch & Tamman, 1992 Frequency (SNu) SNe Ia SNe Ib/c SNe II Sbc-Sd 0. 24± 0. 09 0. 16± 0. 08 0. 88± 0. 37 S 0 a-Sb 0. 20± 0. 07 0. 11± 0. 06 0. 40± 0. 19 E 0. 15± 0. 07 - - Portopalo (Si), 11 -16 June 2017 THE FOURTH AZARQUIEL SCHOOL OF ASTRONOMY Cappellaro+, 1997

SUPERNOVAE: AN INTRODUCTION For the Galaxy: Intermediate galaxy type (Sb-Sc) LB =2× 1010 Lʘ H 0~68 km s-1 Mpc-1 Galactic SN rate: ~1. 3 SNu (one SN per 80 yr) Hystorical galactic SNe: ~0. 17 SNu (one SN per 300 yr) 60 ° Portopalo (Si), 11 -16 June 2017 THE FOURTH AZARQUIEL SCHOOL OF ASTRONOMY

PROGENITORS AND EXPLOSION MECHANISM OBSERVATIONAL EVIDENCE • No H in the spectra at maximum • Only SNe in Ellypticals • SNe Ia explode also in Spyrals • Short duration of the peak phase THEORETICAL DEDUCTION • Progenitors are evolved object • CO WDs as final fate of IM stars • Compact progenitor If a CO WD increases its mass up to the Chandrasekhar mass limit, it heats up and ignites C-burning Portopalo (Si), 11 -16 June 2017 THE FOURTH AZARQUIEL SCHOOL OF ASTRONOMY

PROGENITORS AND EXPLOSION MECHANISM OBSERVATIONAL EVIDENCE • No H in the spectra at maximum • Only SNe in Ellypticals • SNe Ia explode also in Spyrals THEORETICAL DEDUCTION • Progenitors are evolved object • CO WDs as final fate of IM stars • Short duration of the peak phase • Compact progenitor • Longevity of SNe Ia progenitors • CO WDs should be in binary systems • The progenitor is destroyed • The energy delivered in the explosion is employed to eject matter • Fotons carry away only ˜ 1049 erg The explosion produces Fe-peak and intermediate-mass elements Portopalo (Si), 11 -16 June 2017 THE FOURTH AZARQUIEL SCHOOL OF ASTRONOMY

PROGENITORS AND EXPLOSION MECHANISM TOY MODEL Assumptions: Consequences: MWD~MCh~1. 4 Mʘ Delivered nuclear energy: 2× 1051 erg X(12 C)=X(16 O)=0. 5 C-burning produces mainly 56 Ni Gravit. binding energy: 5. 1× 1050 erg The structure becomes unbound Ekinetic Portopalo (Si), 11 -16 June 2017 ~1051 erg THE FOURTH AZARQUIEL SCHOOL OF ASTRONOMY

PROGENITORS AND EXPLOSION MECHANISM Type Ia Supernovae are produced by thermonuclear disruption of Carbon-Oxygen White Dwarfs accreting mass from their companions in binary systems. When MWD approaches MCh a strong compression occurs and Cburning is ignited in the center in highly degenerate (Hoyle & Fowler 1960) physical conditions. REMARK The rareness of SNe Ia and their homogeneity requires a very severe selection criterion for the progenitor Portopalo (Si), 11 -16 June 2017 THE FOURTH AZARQUIEL SCHOOL OF ASTRONOMY

BINARY SYSTEMS: AN INTRODUCTION Primary Secondary Separation Portopalo (Si), 11 -16 June 2017 THE FOURTH AZARQUIEL SCHOOL OF ASTRONOMY

BINARY SYSTEMS: AN INTRODUCTION L 1, L 2, L 3: collinear Lagrangian Points L 1: Inner Lagrangian Point Roche Lobes Roche Radius RR (Paczynski 1971) Portopalo (Si), 11 -16 June 2017 THE FOURTH AZARQUIEL SCHOOL OF ASTRONOMY

BINARY SYSTEMS: AN INTRODUCTION Fully conservative case Non-conservative case Portopalo (Si), 11 -16 June 2017 THE FOURTH AZARQUIEL SCHOOL OF ASTRONOMY

BINARY SYSTEMS: AN INTRODUCTION Detached Semi-detached At contact Portopalo (Si), 11 -16 June 2017 THE FOURTH AZARQUIEL SCHOOL OF ASTRONOMY

EVOLUTION OF THE MASS-LOSING STAR Time scale on which the star loses mass Thermal time scale Portopalo (Si), 11 -16 June 2017 THE FOURTH AZARQUIEL SCHOOL OF ASTRONOMY

EVOLUTION OF THE MASS-LOSING STAR Kippenhahn & Sweigert 1967 Case C Case B Case A Portopalo (Si), 11 -16 June 2017 THE FOURTH AZARQUIEL SCHOOL OF ASTRONOMY

EVOLUTION OF THE MASS-ACCRETING STAR Portopalo (Si), 11 -16 June 2017 THE FOURTH AZARQUIEL SCHOOL OF ASTRONOMY

EVOLUTION OF BINARY SYSTEMS PRIMARY MS Conservative mass transfer RGB/AGB COMMON ENVELOPE Portopalo (Si), 11 -16 June 2017 THE FOURTH AZARQUIEL SCHOOL OF ASTRONOMY

EVOLUTION OF BINARY SYSTEMS SECONDARY Conservative mass transfer MS RGB/AGB Second Common Envelope Episode REMARK Portopalo (Si), 11 -16 June 2017 THE FOURTH AZARQUIEL SCHOOL OF ASTRONOMY

POSSIBLE FINAL SYSTEMS Only one Common Envelope episode CE M 1 remn. 0. 7 -2. 3 RGB He WD 2. 3 -8. 0 RGB He Star 0. 7 -8. 0 AGB CO WD I CE Two Common Envelope episodes Portopalo (Si), 11 -16 June 2017 + H-rich star II CE M 1 remn. M 2 remn. 0. 7 -2. 3 RGB He WD 2. 3 -8. 0 RGB He Star 0. 7 -8. 0 AGB 0. 7 -2. 3 RGB CO WD He WD 0. 7 -8. 0 AGB 2. 3 -8. 0 RGB CO WD He Star 0. 7 -8. 0 AGB CO WD THE FOURTH AZARQUIEL SCHOOL OF ASTRONOMY

HOW CAN THEY EXPLODE? Chandrasekhar 1939 Homologous compression Central Ignition Local Heating Off-center ignition Portopalo (Si), 11 -16 June 2017 THE FOURTH AZARQUIEL SCHOOL OF ASTRONOMY

EVOLUTION TO THE EXPLOSION Explosion Simmering C-Ignition Portopalo (Si), 11 -16 June 2017 THE FOURTH AZARQUIEL SCHOOL OF ASTRONOMY

EXPLOSION MECHANISM: CENTRAL C-IGNITION Flame Propagation Conductively Shock compression Subsonic Supersonic Deflagration Detonation The exploding WD is in sonic ``contact’’ Portopalo (Si), 11 -16 June 2017 THE FOURTH AZARQUIEL SCHOOL OF ASTRONOMY

EXPLOSION MECHANISM: CENTRAL C-IGNITION Low The WD expands The WD can not expand The Flame quenches All the WD in NSE 56 Ni Unburnt 12 C– 16 O Large 56 Ni No IMS Spectra and Light Curve not reproduced ! Delayed Detonation Model Portopalo (Si), 11 -16 June 2017 THE FOURTH AZARQUIEL SCHOOL OF ASTRONOMY Khokhlov 1991

EXPLOSION MECHANISM: DELAYED-DETONATION Portopalo (Si), 11 -16 June 2017 THE FOURTH AZARQUIEL SCHOOL OF ASTRONOMY

EXPLOSION MECHANISM: HE-DETONATION He CO WD The base of the He-buffer attains highly degenerate physical conditions He-flash turns into a detonation Portopalo (Si), 11 -16 June 2017 THE FOURTH AZARQUIEL SCHOOL OF ASTRONOMY

EXPLOSION MECHANISM: HE-DETONATION Portopalo (Si), 11 -16 June 2017 THE FOURTH AZARQUIEL SCHOOL OF ASTRONOMY

EXPLOSION MECHANISM: HE-DETONATION Unburnt He 56 Ni on the surface Portopalo (Si), 11 -16 June 2017 THE FOURTH AZARQUIEL SCHOOL OF ASTRONOMY

SINGLE DEGENERATE SYSTEMS (SDSs) DONOR SYSTEMS MS Star Cataclysmic Variables Novae RG Star Symbiotic Systems Nova-like RG Star Symbiotic Systems PROs CONs They can explode both for central C-Ignition and Hedetonation Portopalo (Si), 11 -16 June 2017 OUTCOME No H-line in the observed spectra No observed radio emission in SNe Ia Frequency of good Sy. Ss THE FOURTH AZARQUIEL SCHOOL OF ASTRONOMY

SDSs: ACCRETION REGIMES Massive He-buffer Mass ejection Cassisi, Iben, Tornambé 1998 Portopalo (Si), 11 -16 June 2017 THE FOURTH AZARQUIEL SCHOOL OF ASTRONOMY

SDSs: FINAL OUTCOMES Cassisi, Iben, Tornambé 1998 Portopalo (Si), 11 -16 June 2017 THE FOURTH AZARQUIEL SCHOOL OF ASTRONOMY

SDSs: FINAL OUTCOMES Piersanti +, 1999 Cassisi, Iben, Tornambé 1998 Portopalo (Si), 11 -16 June 2017 THE FOURTH AZARQUIEL SCHOOL OF ASTRONOMY

SDSs: THE HIGH MASS RANGE Hillman+, 2016 Portopalo (Si), 11 -16 June 2017 THE FOURTH AZARQUIEL SCHOOL OF ASTRONOMY

THE HE-DONOR CHANNEL AM Canum Venaticorum (CVn) Systems He-WD Family He-star Family Case B Mass Transfer Portopalo (Si), 11 -16 June 2017 THE FOURTH AZARQUIEL SCHOOL OF ASTRONOMY

THE HE-DONOR CHANNEL Portopalo (Si), 11 -16 June 2017 THE FOURTH AZARQUIEL SCHOOL OF ASTRONOMY

The RG Configuration Regime Portopalo (Si), 11 -16 June 2017 THE HE-DONOR CHANNEL THE FOURTH AZARQUIEL SCHOOL OF ASTRONOMY

THE HE-DONOR CHANNEL: FINAL OUTCOMES AIC SNe Ia Massive CO WD He-detonation Portopalo (Si), 11 -16 June 2017 THE FOURTH AZARQUIEL SCHOOL OF ASTRONOMY

THE HE-DONOR CHANNEL: HE-DETONATION Portopalo (Si), 11 -16 June 2017 THE FOURTH AZARQUIEL SCHOOL OF ASTRONOMY

DOUBLE DEGENERATE SYSTEMS (DDS) PROs No H and He in DD systems Observed spectra CO rich matter is accreted directly No burning shells and retention efficiency Local Heating Off-center ignition AIC? Homologous compression Central Ignition SN Ia Portopalo (Si), 11 -16 June 2017 THE FOURTH AZARQUIEL SCHOOL OF ASTRONOMY

DOUBLE DEGENERATE SYSTEMS (DDS) Portopalo (Si), 11 -16 June 2017 THE FOURTH AZARQUIEL SCHOOL OF ASTRONOMY

DOUBLE DEGENERATE SYSTEMS (DDS) CONs No observation of ``good’’ DDs KPD 0422+5421 in SPY (Koen+, 1998) Mass transfer rate too high Portopalo (Si), 11 -16 June 2017 THE FOURTH AZARQUIEL SCHOOL OF ASTRONOMY

ROTATING DDS Single CO WDs are slow rotator DDS are sincronized Accreted matter deposits also angular momentum ROTATION CAN NOT BE NEGLECTED IN MODELING MERGING WDs Portopalo (Si), 11 -16 June 2017 THE FOURTH AZARQUIEL SCHOOL OF ASTRONOMY

ROTATING DDS Gravitationally unbound ROCHE INSTABILITY Portopalo (Si), 11 -16 June 2017 THE FOURTH AZARQUIEL SCHOOL OF ASTRONOMY

ROTATING WDs Rotating WDs have lower local effective gravity Rotating WDs attain larger radii! f Portopalo (Si), 11 -16 June 2017 THE FOURTH AZARQUIEL SCHOOL OF ASTRONOMY

ROTATING DDS ROCHE INSTABILITY Self-regulating accretion phase Portopalo (Si), 11 -16 June 2017 THE FOURTH AZARQUIEL SCHOOL OF ASTRONOMY

ROTATING DDS GWR Emission Portopalo (Si), 11 -16 June 2017 THE FOURTH AZARQUIEL SCHOOL OF ASTRONOMY

ROTATING DDS When mass accretion ends the accreted WD is stable. Angular momentum losses The explosion is delayed!!! No evidence for the progenitors in frames from archives! Portopalo (Si), 11 -16 June 2017 THE FOURTH AZARQUIEL SCHOOL OF ASTRONOMY