THE PHYSICS OF COSMOLOGICALLY RELEVANT TYPE IA SUPERNOVAE WHAT IS OLD AND WHAT IS NEW (among news: natura facit saltus) (among news: natura facit saltus) Amedeo Tornambé Amedeo Tornambé OA ROMA‐INAF SIF – BOLOGNA – SETTEMBRE 2010
THE PHYSICS OF COSMOLOGICALLY RELEVANT TYPE IA SUPERNOVAE
WHAT IS OLD AND WHAT IS NEW (among news: natura facit saltus)(among news: natura facit saltus)
Amedeo TornambéAmedeo Tornambé
OA ROMA‐INAF
SIF – BOLOGNA – SETTEMBRE 2010
TYPE IA SUPERNOVAE ARE:TYPE IA SUPERNOVAE ARE:
PARAMOUNT COSMOLOGICAL TOOLS
IN FACT: They are powerfull distance indicators
IRON PRODUCERS
INTRIGUING (ASTRO)PHYS LABSINTRIGUING (ASTRO)PHYS. LABS
(GWR, URCA neutrinos, energy transport ….
OBSERVATIONAL PROPERTIES OF TYPE IA SUPERNOVAE
OBSERVATIONAL PROPERTIES OF TYPE IA SUPERNOVAETYPE IA SUPERNOVAETYPE IA SUPERNOVAE
EXPLOSION ENERGY: ergs (no neutrinos no 5110EXPLOSION ENERGY: ergs (no neutrinos,no compact remnants)
10
BOTH IN YOUNG AND IN OLD STELLAR POLPULATIONS (but the only ones in OLD)POLPULATIONS (but the only ones in OLD)
LIGHT CURVE REACHING MAXIMUM IN ABOUT 15 LIGHT CURVE REACHING MAXIMUM IN ABOUT 15 DAYS THEN DECLINING WITH TWO STEEPNES.
SIMILAR BUT NOT EQUAL LIGHT CURVES (BELIEVED ABSOLUTELY EQUAL UP TO SOME YEARS AGO)
SN 2000Ein NGC 6951in NGC 6951NIR(AZT-24)
SN 2001Vin NGC 3987NIR(AZT-24)
SN 2002boin NGC 3190NIR(AZT-24)
Barbon, Ciatti and Rosino 1973
THEY WERE THOUGHT TO BETHEY WERE THOUGHT TO BE
STANDARD CANDELS
THIS IS NO MORE TRUETHIS IS NO MORE TRUE
BUT
THEY CAN BE STANDARDISED
ADDITIONAL OBSERVATIONAL ISSUES ARE:ADDITIONAL OBSERVATIONAL ISSUES ARE:
SNIA in ellipticals less luminous than those in spyrals (as a mean)
SNIA rates linked both with SFR and with the whole mass of the parent systeme o e ass o e pa e sys e
Half production occurring in a short time after theHalf production occurring in a short time after the birth of the parent population (hundreds mill. Yrs)
PER POTERLE UTILIZZARE CON TRANQUILLITA’ OCCORRE SAPERNE DI PIU’OCCORRE SAPERNE DI PIU
cosa sono esattamente e quale è stata q
l’evoluzione dei progenitori stellari?
Ci sono più famiglie??p g
Da dove proviene l’energia che alimenta
l’esplosione?l esplosione?
Perché sono ‘auto‐simili’?
STATO Dell’ ARTESTATO Dell ARTE
(i1 SOLAR MASS OF INCINERATED C+O (i.e.:FULLY & SUDDENLY BURNED TO IRON GROUP ELEMENTS) PROVIDES ERGS
5110
(RECOGNISED SOME 50 YRS AGO)
NECESSARIO UN AMBIENTE AD ALTANECESSARIO UN AMBIENTE AD ALTA DEGENERAZIONE ELETTRONICA
( THE CHANDRASEKHAR MASS)( THE CHANDRASEKHAR MASS)
St i t th k t th di tStars exist thanks to the pressure gradient
I “ l” t th f ti l d i tIn “normal” stars the free particles pressure dominates and the standard EOS is at work
In Dwarf Stars it is the pressure of the degenerate electrons to dominateelectrons to dominate
The mass of Degenerate Stars cannot exceed theThe mass of Degenerate Stars cannot exceed the Chandrasekhar limiting mass. If they exceed they will collapse or explode.
CHANDRASEKHAR MASSCHANDRASEKHAR MASS
222/35.02 )/()32/9( ench YmGcM −= hπ265 YM ≅ 6.5 ech YM ≅
limiting masses in standard conditionslimiting masses in standard conditions
H dominated matter Sh MM 65≈ Sunch MM 6.5≈
Helium, Carbon, Oxygen Sunch MM 4.1≈
Iron Sunch MM 1.1≈
Single stars cannot attain the Ch d M !!!!Chandra Mass !!!!
Lets inquire on the evolution of qbinary systems
ORIGINAL SYSTEM
MM 7=
ORIGINAL SYSTEM
sunMM 7 1 =
sunMM 52 =
A binary system with two intermediate mass stars.
Say: 7 and 5 solar masses and original separation ASay: 7 and 5 solar masses and original separation A
DEGENERATEDEGENERATE CO CORE
CONVECTIVE EXPANDED ENVELOPE
After the end of central He burning the primary develops a degenerate CO core and the envelope expands to red giant conditions
FIRST COMMON ENVELOPE EPISODE
A Common Envelope phase ensues The convectiveA Common Envelope phase ensues. The convective envelope of the primary expands and engulfs the secondary. While the envelope matter becomes lost y pfrom the external lagrangian points the separation is reduced.
FIRST INTERMEDIATE PHASE
2' /MMAMA = 121R /MM AMA =
The outcome of the first CE episode is a bare COThe outcome of the first CE episode is a bare CO white dwarf and a normal star almost unaffected by the CE stage.g
ONE POSSIBLE EVOLUTIONARY CHANNEL(depending on mass and separation)
C OC+O dwarf H rich star
Low H transferM&
STEADY H MASS TRANSFER AT LOW RATE,
NOVA LIKE PHENOMENA.
H burning into He and He burnong into C+O requiredrequired
A DIFFERENT EVOLUTIONARY CHANNEL
(depending on mass and separation)
DEGENERATE CORE
CONVECTIVE EXPANDED ENVELOPE
IF SEPARATION IS RATHER LARGE THE SECONDARY EVOLVES UP
TO RED GIANT DIMENSION BEFORE STARTING INTERACION
EVOLUTION ALONG THE SECOND CHANNEL
SECOND COMMON ENVELOPE PHASE
THE INTERACTION OF THE EXPANDEDTHE INTERACTION OF THE EXPANDED CONVECTIVE ENVELOPE WITH THE REMNANT OF THE PRIMARY GIVES RISE TO A SECOND CE EPISODE. ONCE AGAIN THE ENVELOPE BECOMES LOST.
A SECOND POSSIBLE EVOLUTIONARY CHANNEL
Ω21R1R2R
' M/ M MAA =f
GWRGWR
Ω 1R1R2Rf
GWR
A SYSTEM OF TWO VERY CLOSE WDsA SYSTEM OF TWO VERY CLOSE WDs
SEPARATION SHRINKS BECAUSE OFSEPARATION SHRINKS BECAUSE OF
GRAVITATIONAL WAVE EMISSION
MERGING TIMEMERGING TIME
yrsMMMMA RRRRfmerg ))(/(10 5.1 212148 +=τ
FOR OF THE ORDER OF THE SOLAR RADIUS fA
AND M OF THE ORDER OF
f
THE SOLAR MASS THE MERGING TIME IS ONLY
yrs 108 (BUT IT CAN BE ALSO SEVERAL BILLION
YEARS)
AMBEDUE IAMBEDUE I CANALICANALI PRESENTANOPRESENTANO DIFFICOLTA’DIFFICOLTA’
SUMMARISING:SUMMARISING:WHAT SEEMS TO BE KNOWN:HOW THEY EXPLODE (THE ENGINE)
WHAT IS UNKNOWN:HOW THEY MANAGE TO SWITCH ON THE ENGINEHOW THEY MANAGE TO SWITCH ON THE ENGINE (i.e. HOW THEY TUNE THE MASS ACCRETION)
REQUIREMENTS TO BE FULFILLED ARE: &IT HAS TO BE A BINARY SYSTEM & TIME SCALES MUST
RANGE FROM FEW 10^8 yrs TO THE PROTON DECAY TIME
A RECENT APPROACH TO THE WD MERGING ISSUE
INTRODUCE ROTATION IN MODEL
A RECENT APPROACH TO THE WDs MERGING ISSUE
INTRODUCE ROTATION IN MODEL COMPUTATION
ΩTWO WDs IN A TIGHT BINARY
ΩSYSTEM MERGE BECAUSE OF GWR EMISSION
M1 M2
THEY BECOME SYNCHRONISED WELL BEFORE MERGING.
M1 M2
M1>M2 M1 M2>1 4 M
ONCE SYNCHRONISATION IS ATTAINED IT WILL BE NEVER LOST.M1>M2 M1+M2>1.4 Msun LOST.
Ω THE LESS MASSIVE WD IS DISSOLVEDTHE LESS MASSIVE WD IS DISSOLVED IN A DISK
ACCRETION DISK PRODUCED BY THE LESS MASSIVE WD
THE MORE MASSIVE WD ACCRETESMASS AND MOMENTUM
NUMERICAL RESULTSNUMERICAL RESULTS:ACCRETION IS SELF-TUNED ON A-PARAMETRIC PHYSICAL PARAMETERS OF THE SYSTEM
IN FACT:Phase 1
IN FACT:Ω=Ωcrit
EVOLUTIONARY STEPS:EVOLUTIONARY STEPS:
VERY SOON CRITICAL ROTATIONAL VELOCITY IS ATTAINED.
ACCRETION COMES TO A HALT
IN ADDITION THERE IS AN ENERGYEXCESS STORED IN THE EXTERNALLAYERS.
AS SOON AS THE ENERGY EXCESS IS
ACCRETING MASS ANDANGULAR MOMENTUM
REMOUVED (TRANSFERRED TO THE CENTRAL LAYERS) THE DWARF BECOMES SUBCRITICAL.
ACCRETION RESTARTS.
Phase 2Phase 2
At the end of phase 1 the accreting WD has
Become so fast spinning and so compressed
To become secularly unstable to a deformation
Into a triaxial Jacobi ellipsoidInto a triaxial Jacobi ellipsoid
EE / approaches grot EE / =γ 14.0 ≈crγ
EMISSION OF GWR BEGINS AND LASTS FOR
A LONG TIMEA LONG TIME
Phase 2GWR REMOVES ANGULAR MOMENTUM
According to Chandrasekar 1970 and Friedman & Schutz 1975
GWRtJdtdJ τ/1/ −− GWRtGWR eJdtdJ ττ /1
0 / −=
Where [ ] 65)
8 (/ 10 −− −≈ ωγγτ CRGWR Rc
And grot EE / =γ
Phase 3Phase 3Accretion rate drops as the accreting WDAccretion rate drops as the accreting WD
turns back into a stable MacLaurin speroid
But the mass has already been incresed
much over the ‘non‐rotating’ Chanrasekhar
mass.
Viscous interaction with the remnant of theViscous interaction with the remnant of the
disk brakes down the WD and leads it to
explode
SO FAR FOR RIGID ROTATIONSO FAR FOR RIGID ROTATION
(MASS SPREADS BETWEEN 1.4 AND 1.5(
SOLAR MASSES)
INTRODUCE A VERY NEW (PROVOCATIVE) ROAD ( )
WHAT IS REALLY NEW:WHAT IS REALLY NEW:
THE EVOLUTIONARY SCENARIO IN
CASE OF DIFFERENTIAL ROTATION:
(NATURA ABHORRET CHANDRA)
IN CASO DI ROTAZIONE DIFFERENZIALE….
UNA STRUTTURA PUO’ ESSERE STABILE FINO A
4 MASSE SOLARI (!)4 MASSE SOLARI (!)
DURANTE TUTTA LA FASE DI ACCRESCIMENTO
RIMANE ATTIVA LA ROTAZIONE DIFFERENZIALERIMANE ATTIVA LA ROTAZIONE DIFFERENZIALE
ED E’ POSSIBILE TRASFERIRE TUTTA LA MASSA
DISPONIBILE ANCHE OLTRE LA Mch CLASSICA (in
pratica nel mondo reale fino a 2 2 masse solari)pratica, nel mondo reale, fino a 2.2 masse solari)
FINITO L’ACCRESCIMENTO, LA ROTAZIONE
DIFFERENZIALE TENDE AD ESTINGUERSI.
A QUESTO PUNTO QUESTE STRUTTURE SI
DESTABILIZZANO IN MODO NATURALE E
NON POSSONO FARE ALTRO CHE CONTRARRENON POSSONO FARE ALTRO CHE CONTRARRE
VIOLENTEMENTE, INNESCARE IL BRUCIAMENTO ,
CENTRALE DEGENERE DEL CARBONIO ED
ESPLODERE
LA PRIMA CONSEGUENZA E’ UNLA PRIMA CONSEGUENZA E’ UN REALE CAMBIO DI PROSPETTIVAREALE CAMBIO DI PROSPETTIVA
IN NATURA IL PROCESSO NON E’ PIU’ QUELLO DI
RAGGIUNGERE UNA MASSA CRITICA MA
QUELLO DI RECEDERE DA UNA CONDIZIONE DIQUELLO DI RECEDERE DA UNA CONDIZIONE DI
sovra‐STABILITA’ (di nuovo come nelle cc SNe)
Sub chandra SI – Chandra NO (!)Sub‐chandra SI – Chandra NO (!)
IL BILANCIO ENERGETICO:IL BILANCIO ENERGETICO:
STORED ROTATIONAL ENERGY MAY AMOUNT
UP TO MORE THAN 5x10^50 ergs (i.e. 0.5 solarUP TO MORE THAN 5x10 50 ergs (i.e. 0.5 solar
masses of eq. Ni) DEPENDING ON THE MASS
AS A MEAN AN INCREASE OF 0 1 Msun IN THEAS A MEAN AN INCREASE OF 0.1 Msun IN THE
TOTAL MASS AT EXPLOSION CORRESPONDS TO
AN INCREASE OF LUMINOSITY OF MORE THAN
ONE TENTH OF magnitudeONE TENTH OF magnitude
ADDITIONAL CONSEQUENCES of the new scenario are:
• Mass spectrum of SNe no more peaked at around 1.4 solar masses
• Masses will range from 1.38 up to 2.2 Msun
more massive more brightmore massive more bright
• There is a difference between short and long living systems: brighter sooner
• A second stage of GWR is identified after theA second stage of GWR is identified after the starting of the merging process
Observational Evidence:Sooner ‐ Brighter
(Gallagher et al. 2005)
Theoretical Prediction:Sooner ‐ Brighter
CONCLUSIONSSelected systems of intermediate mass stars may finish their lives with fireworks
Differential rotation plays a pivotal role in p y pproducing fireworks AND A NEW PERSPECTIVEon how these occur has to be assumed
The DD scenario including diff. rotation is able to gaccount for a variety of observational issues: brighter sooner, rates, fast/slow evolving systemsg , , / g y
Predictions can be done: GWR
conseguenze cosmologiche:conseguenze cosmologiche:
NON EMERGE NESSUN INDIZIO CHE POSSA FARNON EMERGE NESSUN INDIZIO CHE POSSA FAR
CONSIDERARE LE SUPERNOVAE PRIMORDIALI
INTRINSECAMENTE DIVERSE RISPETTO A QUELLE
ATTUALIATTUALI
THE END