evolutionary path toward the core collapse supernova explosion
DESCRIPTION
EVOLUTIONARY PATH TOWARD THE CORE COLLAPSE SUPERNOVA EXPLOSION. Marco Limongi INAF – Osservatorio Astronomico di Roma, ITALY Institute for the Physics and Mathematics of the Universe , JAPAN marco.limongi@ oa-roma.inaf.it. and Alessandro Chieffi - PowerPoint PPT PresentationTRANSCRIPT
EVOLUTIONARY PATH TOWARD THE CORE COLLAPSE SUPERNOVA
EXPLOSION
and
Alessandro ChieffiINAF – Istituto di Astrofisica Spaziale e Fisica Cosmica, Italy
Marco LimongiINAF – Osservatorio Astronomico di Roma, ITALY
Institute for the Physics and Mathematics of the Universe, [email protected]
OVERVIEW OF MASSIVE STARS PRESUPERNOVA EVOLUTIONGrid of models: 13, 15, 20, 25, 30, 40, 60, 80 and 120 M
Initial Solar Composition (Asplund et al. 2009)All models computed with the FRANEC (Frascati RAphson Newton
Evolutionary Code) 6.0Major improvements compared to the release 4.0 (Limongi & Chieffi 2003) and 5.0 (Limongi & Chieffi 2006)
- FULL COUPLING of: Physical Structure - Nuclear Burning - Chemical Mixing (convection, semiconvection, rotation)
- INCLUSION OF ROTATION:- Conservative rotation law- Transport of Angular Momentum (Advection/Diffusion)- Coupling of Rotation and Mass Loss
- TWO NUCLEAR NETWORKS:- 163 isotopes (448 reactions) H/He Burning- 282 isotopes (2928 reactions) Advanced Burning
- MASS LOSS:- OB: Vink et al. 2000,2001- RSG: de Jager 1988+Van Loon 2005 (Dust driven
wind)- WR: Nugis & Lamers 2000/Langer 1989
MASSIVE STARS: CORE H BURNING
g
g
g
g
g
g
g
g
CNO Cycle
Convective Core
Core H burning models
WNL
WNL
MASSIVE STARS: CORE He BURNING
gg
g
g
g
g
g
g
He Convective Core
3a+ 12C(a,g)16O
H burning shellH exhausted
core (He Core)
The Mass Loss rate during the RSG phase is crucial in determining if and
when (at which stage of core He burning) such a transition occurs and if and when the star enters the Wolf-
Rayet stage or becomes a YSG
The location of a core He burning star in the HR diagram depends on the mass of its H
envelope.
Core H burning models
Core He burning models
Core He burning models
WR
WNLWNE WNCWC
WNL
WNEWNC
WC
WNLWNE WNCWC
WNL
WNEWNC
WC
EVOLUTION DURING H AND He BURNING: SUMMARY
Initial Mass
Final Mass
MH MHe Progenitor
SN
13 12.0 5.46 4.49 RSG II-P15 13.4 5.75 4.90 RSG II-P20 8.1 0.25 3.81 RSG IIb25 10.4 0.14 4.42 YSG IIb30 12.6 0.03 4.35 YSG IIb/Ib40 16.0 0.00 4.22 WNE Ib/c60 16.8 0.00 0.93 WC Ib/c80 22.6 0.00 1.07 WC Ib/c
120 30.8 0.00 1.02 WC Ib/c
Compatible with recent observational estimates (Smartt et al. 2009):
Compatible with the observed rates (Cappellaro & Turatto 99)
Live a substantial fraction of time as RSG and explode as as IIb/Ib solve the RSG problem (Smartt et al. 2009)
COMPARISON WITH WOLF-RAYET STARS POPULATION
Constant SF + Salpeter IMF
- WNC/WR in good agreement with observations (semiconvection during core He burning) – MM03 claimed that such an agreement could be achieved only with the inclusion of rotation
- Too many WN predicted compared to WCO
- Too few WR-stars predicted compared to O-type stars
- WR predicted masses higher than the observed ones
MASSIVE STARS: NEUTRINO LOSSES
The Nuclear Luminosity (Lnuc) closely follows the energy losses
nuc
nuc
EL Mt
nuc nucMt EL
Evolutionary times of the advanced burning stages
reduce dramatically
Each burning stage gives about the same Enuc
Surface properties (Mass Loss, Teff, L) do not change anymore
till the explosion
Neutrino losses play a dominant role in the evolution of a massive star beyond core He burning
ADVANCED BURNING STAGES: INTERNAL EVOLUTIONFour major burnings, i.e., carbon, neon,
oxygen and silicon.
Central burning formation of a convective coreCentral exhaustion shell burning convective shell
Local exhaustion shell burning shifts outward in mass convective shell
C
C
CC
He
Ne O
OO
Si
Si
HeH
ADVANCED BURNING STAGES: INTERNAL EVOLUTIONThe details of this behavior (number, timing, mass extension and overlap of convective shells) is mainly driven by the CO
core mass and by its chemical composition (12C, 16O)CO core mass Thermodynamic history
12C, 16O Basic fuel for all the nuclear burning stages after core He burning
At core He exhaustion both the mass and the composition of the CO core scale with the initial mass…
ADVANCED BURNING STAGES: INTERNAL EVOLUTION
C
C
CC
He
NeO
OO
Si
Si
HeH H He
C
He
Ne OO
Si
...hence, the evolutionary behavior scales as well
In general, one to four carbon convective shells and one to three convective shell episodes for each of the neon, oxygen and silicon
burnings occur.
The number of C convective shells decreases as the mass of the CO core increases (not the total mass!) or asthe 12C left over by
core He burning decreases.
Si
PRESUPERNOVA STAR…and also the density structure of the star at the presupernova stage
The final Fe core Masses range between:
In general the higher is the mass of the CO core (the lower is the 12C left over by the core He burning), the more compact is the
structure at the presupernova stage
MFe=1.14-1.80 M
PRESUPERNOVA STARThe complex interplay among the shell nuclear burnings and the timing of the convective zones determines in a direct way the final distribution
of the chemical composition. The mass loss history (RSG/WR) determines in a direct way the kind of CCSN
INDUCED EXPLOSION AND FALLBACK
Fe core
Shock WaveCompression and Heating
Induced Expansion
and Explosion
Initial Remnan
t
Matter Falling Back
Mass Cut
Initial Remnan
t
Final Remnant
Matter Ejected into the ISMEkin1051 erg
Different ways of inducing the explosion
FB depends on the binding energy: the higher is the initial mass the higher is the binding energy
• Piston (Woosley & Weaver)• Thermal Bomb (Nomoto & Umeda)• Kinetic Bomb (Chieffi & Limongi)
THE FINAL FATE OF A MASSIVE STAR
Thorsett & Chakrabarty (1999)
No neutron stars formed by massive progenitors (contrary to recent observational evidences, see Smartt et al. 2009)
Hydrodynamic models based on induced explosions
No (or very few) bright SNIb/c predicted
SUMMARY Maximum mass evolving as a RSG on a substantial fraction of core He burning
Mmax,RSG ~ 35 M
RSG/YSG/BSG SNe as a function of the initial mass
M ≤ 22 M RSG-SN22 M < M ≤ 35 M YSG-SN35 M < M BSG-SN
The minimum masses for the formation of the various kind of Wolf-Rayet stars are:
MWNL ~ 23 M
MWNE ~ 35 M
MWC ~ 45 M
- WNC/WR in good agreement with observations- Too many WN predicted compared to WCO
- WR/O significanlty underestimated compared to observations
- WR predicted masses higher than the observed ones
- Consistent with the maximum luminosity of galactic RSG stars
SUMMARYMaximum mass for SNII-P Mmax,IIP ~ 17 M
- Consistent with the recent observational estimates (Smartt et al. 2009)
Minimum mass for SNIb/c: MSNII/SNIbc ~ 35 M
In principle compatible with the observed rates
The final Fe core Masses range between:
MFe=1.14-1.80 M
The limiting mass between NS and BH froming SNe :
MNS/BH ~ 22 M
in agreement with
Because of the large fallback No (or very few) bright SNIb/c predicted
- Large uncertainties in treatment of the fallback- Mixing and Fallback (Umeda & Nomoto)- Larger energies / Binary channel
PHYSICS OF ROTATIONSTRUCTURE• Oblateness (interior, surface)• New structure equations
Von Zeipel Theorem
Meridional Circulation
Local conservation Meridional circulation
Advection of angular
momentum
Increase the gradient of
angular velocity
Shear Instabiliti
esTransport of Angular Momentum
Transport of Chemical Species
G. Meynet G. Meynet
ROTATING MODELS
THE EFFECT OF ROTATION
- Progressive reduction of the effective gravity from the pole to the equator- Mixing of core nuclear burning products outward and fresh material inward
- Different path in the HRD diagram- Increase of the nuclear burning lifetimes- Increase of the mean molecular weight of the envelope- Different mass loss history- Early entrance in the WR phase Different mass limits and
lifetimes for the various WR stages
THE EFFECT OF ROTATION
- Progressive reduction of the effective gravity from the pole to the equator- Mixing of core nuclear burning products outward and pristine material inward
- Different path in the HRD diagram- Increase of the nuclear burning lifetimes- Different mass loss history- Early entrance in the WR phase Different mass limits and
lifetimes for the various WR stagesNo Rotation
Rotation
Mmin(WNL) 23 17Mmin(WNE) 35 100Mmin(WNC) 50 17Mmin(WCO)
45 35
THE EFFECT OF ROTATION
- Good fit to WR/O- Discrepancies between predicted and observed
WR ratios- Good fit to the WR luminosities
THE EFFECT OF ROTATION
Initial Mass
Final Mass
MH MHe Progenitor
SN
13 12.0 5.46 4.49 RSG II-P15 13.4 5.75 4.90 RSG II-P20 8.1 0.25 3.81 RSG IIb25 10.4 0.14 4.42 YSG IIb30 12.6 0.03 4.35 YSG IIb/Ib40 16.0 0.00 4.22 WNE Ib/c60 16.8 0.00 0.93 WC Ib/c80 22.6 0.00 1.07 WC Ib/c
120 30.8 0.00 1.02 WC Ib/c
NO ROTATIONInitial Mass
Final Mass
MH MHe Progenitor
SN
13 9.54 3.16 2.75 RSG II-P15 8.44 1.76 2.15 RSG II-P20 7.39 0.00 0.74 WNC Ib25 9.25 0.00 0.75 WNC Ib30 11.8 0.00 0.78 WNC Ib40 14.2 0.00 0.57 WC Ib/c60 18.6 0.00 0.45 WC Ib/c80 22.5 0.00 0.45 WC Ib/c
120 22.5 0.00 0.63 WC Ib/c
WITH ROTATION
OK OK
OK Too many SNIb/c
predicted
ROTATING MODELS
Rotational mixing during core He burning brings continuously fresh He from the outer zones into the convective core
substantial reduction of the 12C mass fraction left over by core He burning especially in the less massive stars where this mechanism is more efficient due to their higher He burning lifetimes (80-120
are exceptions)
ROTATING MODELS....hence the behavior of any given rotating star during the more advanced burning stages will resemble that of a non rotating star
having a higher mass (80-120 exceptions)rotating models appear much more compact compared to the non
rotating ones
the iron cores are larger as well and range between
MFe=1.7-2.3 M
THE FINAL FATE OF ROTATING MODELS
Substantially larger than the observed value
No neutron stars formed by massive progenitors (contrary to recent observational evidences, see Smartt et al. 2009)
Hydrodynamic models based on induced explosions
Bright SNIb/c produced by rapid rotation?
EVOLUTION OF THE ANGULAR MOMENTUM
From Core He exhaustion onward the evolution of the angular momentum is dominated by the local conservation and by the
convective mixing
During core H burning the angular momentum transport is dominated by the meridional circulation and by mass loss – the relative efficiency
depending on the initial mass
IMPLICATIONS FOR YOUNG PULSARS AND GRBsIf the hydrodynamical simulations are wrong and we assume that all the
stars would collapse to a NS with a mass corresponding roughly to the Iron Core Mass and a Radius of 12 Km
These models have even much more angular momentum in the collapsing iron core than a neutron star can possibly carry
Treatment of angular momentum transport still highly uncertain (advection/diffusion, transport mechanisms and
their efficiency) should be revisedImportant the role of magnetic field (see Heger et al. 2005)
If the large angular momenta obtained for the iron cores in this work may pose a problem for pulsars, they are very favorable
for the GRBs
IMPLICATIONS FOR YOUNG PULSARS AND GRBs
minimum value needed to make a long GRB by magnetar or collapsar formation (Burrows
et al. 2007)
These models imply that all WR stars can retain enough angular momentum to produce GRBs, either by magnetar or collapsar formation
depending on the final mass. This gives a nearly 1000 times higher ratio of GRBs to SNe than the observationally implied value.
The inclusion of a more efficient mass loss during the RSG phase (dust driven wind) lowers the maximum mass for SN-IIP from ~ 30 M (old models) to ~ 17 M without changing the maximum mass
evolving as RSG, independent of rotationThe inclusion of rotation reduces the minimum mass that become a WR star from ~ 22 M (non rotating models) to ~ 17 M and the
minimum masses for all the various WR stages and also the minimum mass for SNIb/c from ~ 30 M (non rotating models) to
~ 17 M - Improve the fit to WR/O and to WR luminosities- Discrepancies between predicted and observed WR
ratios still remain - Sharp transition from SNIIP to SNIb - too many
SNIb/c predictedRotating models are much more compact and with larger iron cores
than the non rotating ones- Implications for CCSN explosion simulations- Average mass of NS remnant larger than observed- Lowering of the MNS/BH from 22 to 14 (simulated
explosion uncertain)The angular momentum of the core of rotating models is too large:
- NS remnants rotating too fast
- GRB/SN ratio severely overestimated
SUMMARY