NUCLEOSYNTHESIS IN STELLAR EVOLUTION AND EXPLOSIONS: ABUNDANCE YIELDS FOR

CHEMICAL EVOLUTION. MASSIVE STARS

Marco LimongiINAF – Osservatorio Astronomico di Roma, ITALY

andCentre for Stellar and Planetary Astrophysics

Monash University – AUSTRALIAEmail: marco@oa-roma.inaf.it

Alessandro Chieffi

Work with:

Massive Stars, those massive enough to explode as supernovae, play a key role in many fields of astrophysics:

Evolution of Galaxies:

Light up regions of stellar birth induce star formation

Production of most of the elements (those necessary to life)

Mixing (winds and radiation) of the ISM

Production of neutron stars and black holes

Cosmology (PopIII):

Reionization of the Universe at z>5

Massive Remnants (Black Holes) AGN progenitors

Pregalactic Chemical Enrichment

High Energy Astrophysics:

Production of long-lived radioactive isotopes: (26Al, 56Co, 57Co, 44Ti, 60Fe)

GRB progenitors

The understanding of these stars, is crucial for the interpretation of many astrophysical objects

Outline

Basic PreSN Evolutionary Properties of Massive Stars and Their Uncertainties

Explosive Nucleosynthesis and its uncertainties

Present Status of the presupernova and explosion modelling of Massive Stars

Comparison among available yields

Strategies for improvements

H Conv. core

CNO Cycle

H burning

Mmin(O) = 14 M

t(O)/t(H burning): 0.15 (14 M ) – 0.79 (120 M)

MASS LOSS

t=2 107 yr

1H 4He

CNO 13C,14N, 17O

NeNa,MgAl 23Na, 26Al

Hs=0.695Hes=0.285

Cs=3.18 10-3

Ns=1.16 10-3

Os=1.00 10-2

1H 4He

CNO 13C,14N, 17O

NeNa,MgAl 23Na, 26Al

t=3.6 106 yr

1H 4He

CNO 13C,14N, 17O

NeNa,MgAl 23Na, 26Al

t=2.7 106 yr

WIND

WIND

Hs=0.566Hes=0.414

Cs=8.42 10-5

Ns=1.30 10-2

Os=7.18 10-4

26Als=2 10-6

t=6.8 106 yr

1H 4He

CNO 13C,14N, 17O

NeNa,MgAl 23Na, 26Al

Hs=0.194Hes=0.786

Cs=1.18 10-4

Ns=1.34 10-2

Os=1.59 10-4

26Als=7 10-6

WNL/yrM 1010 O46 M

/yrM 1010 O46 M

Major Uncertainties in the computation of core H burning models:

Extension of the Convective Core (Overshooting, Semiconvection)

Mass Loss

Both influence the size of the He core that drives the following evolution

3+

12C(,)16O

He burning

The properties of core He burning mainly depend on the size of the He core

M ≤ 35 M RSG

M > 35 M BSG

t=2.0 107 yr t=1.5 106 yr

11

4He 12C, 16O22Ne, s-proc

4He, 14N

t=6.8 106 yr t=5.3 105 yr

4He, 14N

4He 12C, 16O22Ne, s-proc

25 Hs=0.649Hes=0.331

Cs=2.00 10-3

Ns=4.37 10-3

Os=7.86 10-3

Hs=0.000Hes=0.516

Cs=0.397Ns=0.000Os=0.06

4He, 12C

4He 12C, 16O22Ne, s-proc

t=3.6 106 yr t=3.6 105 yr

WNLWNE

WC

60120

t=2.7 106 yr t=3.0 105 yr

4He, 12C4He 12C, 16O

22Ne, s-proc

Hs=0.000Hes=0.422

Cs=0.432Ns=0.000Os=0.119WNL

WNEWC

4,610 M

310M

5.410M510M

4,610 M

410M

5.410M

7.4,510 M

Major Uncertainties in the computation of core He burning models:

Extension of the Convective Core (Overshooting, Semiconvection)

Central 12C mass fraction (Treatment of Convection + 12C(,)16O cross section)

Mass Loss (determine which stars explode as RSG and which as BSG)

All these uncertainties affect the size of the CO core that drives the following

evolution

22Ne(,n)25Mg (main neutron source for s-process nucleosynthesis)

Advanced burning stages

Neutrino losses play a dominant role in the evolution of a massive star beyond core He burning

At high temperature (T>109 K) neutrino emission from pair production start to

become very efficienteeee

L

MEt nucnuc Evolutionary times

reduce dramatically

costL

LL 108 1010

After core He burning

At Pre-SN stage

M < 30 M Explode as RSG

M ≥ 30 M Explode as BSG

Synthesis of Heavy Elements

At high tempreatures a larger number of nuclear reactions are activated

Heavy nuclei start to be produced

C-burning K 10~ 9T Ne-burning K 103.1~ 9T

Synthesis of Heavy Elements

O-burning K 102~ 9TWeak Interactions become efficient

Efficiency scales inversely with the mass

Synthesis of Heavy Elements

At Oxygen exhaustion K 105.2~ 9T Balance between forward and reverse reactions for

increasing number of processes a + b c + d

At Oxygen exhaustion

K 105.2~ 9T

Si

Sc

Equilibrium

At Si ignition

K 105.3~ 9T

Out of Equilibrium

Equilibrium

Partial Eq.

Out of Eq.

At Si ignition(panel a + panel b)

K 105.3~ 9T

A=44A=45

Eq. Clusters

28Si

56Fe

56,57,58Fe, 52,53,54Cr, 55Mn, 59Co, 62Ni

NSE

Ca),(K

Sc),(Sc Ti),(Ca

Ti),(Ca Ti),(Sc

Ti),(Ti Ti),(Ca

Ti),(Ca Ca),(Sc

Sc),(Ca Ca),(Ca

4441

45444643

45414544

45444542

46424444

45424443

p

nn

p

nn

pn

pn

He

CO

Ne/OO

Si

“Fe”

H

He

CO

Ne/O OSi

“Fe”

H

He

CO

Ne/O O Si“Fe”

H

He

CO

Ne/O OSi “Fe”

H

11 M 25 M

60 M 120 M

103 yr 3yr0.3yr 5 days

Burning Site Main Products

Si Burning 56,57,58Fe, 52,53,54Cr,

55Mn, 59Co, 62Ni

O Conv. Shell 28Si, 32S, 36Ar, 40Ca, 34S, 38Ar

C Conv. Shell 20Ne, 23Na, 24Mg,25Mg, 27Al + s-process

He Central 16O, 12C + s-process

He Shell 16O, 12C

H Central+Shell

14N, 13C, 17O

Si

bu

rnin

g(C

en

t.+

Se

hll

)

O c

on

v.

Sh

ell

C c

on

v.

Sh

ell

He

Ce

ntr

al

He

Sh

ell

H S

he

ll

H C

en

tra

l

16O28Si

20Ne

12C

4He1H

“Fe”

Chemical Composition at the PreSN stage

Final Masses at the PreSN stage

No Mas

s Loss

Final Ma

ss

He-Cor

e Mass

He-CC Mass

CO-Core

Mass

Fe-Core Mass

WNLWNE

WC/WO

RSG

Radius

WIND

HEAVY ELEMENTS

Major Uncertainties in the computation of the advanced burning stages:

Treatment of Convection (interaction between mixing and local burning, stability criterion behavior of convective shells final M-R relation explosive nucleosynthesis)

Computation of Nuclear Energy Generation (minimum size of nuclear network and coupling to physical equations, NSE/QSE approximations)

Weak Interactions (determine Ye hydrostatic and explosive nucleosynthesis behavior of core collapse)

Nuclear Cross Sections (nucleosynthesis of all the heavy elements)

Neutrino Losses

Partition Functions (NSE distribution)

Explosive Nucleosynthesis and Chemical Yields

Explosion Mechanism Still Uncertain

Piston

The explosion can be simulated by means of a piston of initial velocity v0, located near the edge of the iron core

v0 is tuned in order to have a given amount of 56Ni ejected and/or a corresponding final kinetic energy Ekin

•Explosion: 1D PPM Lagrangian Hydrocode (Collella & Woodward 1984)

•Explosive Nucleosynthesis: same nuclear network adopted in the hydrostatic evolutions

16O28Si

20Ne

12C

4He1H

“Fe”

Pis

ton S

i bu

rnin

g

O c

on

v. S

hel

l

C c

on

v. S

hel

l

He

Cen

tral

He

Sh

ell

H S

hel

l

H C

entr

al

The Final Fate of a Massive Star

No Mas

s Loss

Final Ma

ss

He-Cor

e Mass

He-CC Mass

CO-Core Mass

Fe-Core Mass

WNLWNE

WC/WO

Remnant Mass

Neutron Star

Black Hole

SNII SNIb/c

Fallback

RSG

Z=Z

E=1051 erg

Initial Mass (M)

Mass (M

)

ScTiFeCoNi

VCrMnTiFeSiSArCa

SiSArCaK

NeNaMgAlPCl

f(,T,Ye) f(,T,Xi)

43

3

4TarE RADIATION DOMINATED:

Si-c Si-i Ox Ne/Cx

NSE/QSE

Individual Yields

Different chemical composition of the ejecta for different masses

Averaged Yields

Yields averaged over a Salpeter IMF 2.35 kmm )(

Global Properties:

Initial Composition (Mass Fraction)

X=0.695Y=0.285Z=0.020

Final Composition (Mass Fraction)

X=0.444 (f=0.64)Y=0.420 (f=1.47)Z=0.136 (f=6.84)

NO Dilution

Mrem=0.186

Major Uncertainties in the simulation of the explosion (remnant mass – nucleosynyhesis):

Prompt vs Delayed Explosion (this may alter both the M-R relation and Ye of the presupernova model)

How to kick the blast wave:

Thermal Bomb – Kinetic Bomb – Piston

Mass Location where the energy is injected

How much energy to inject:

Thermal Bomb (Internal Energy)

Kinetic Bomb (Initial Velocity)

Piston (Initial velocity and trajectory)

How much kinetic energy at infinity (typically ~1051 erg)

Nuclear Cross Sections and Partition Functions

Authors Mass Range

Z Network Mass Loss

Rot. 12C()16O Convection Explosion

CL (2004) 13-35 0.00-0.02

300 itosopes

Fully Coup. (H-Mo)

NO NO Kunz 2001 Schwarz.Semi NONot Coupled

Hydro/PistonPrompt

LC (2006) 11-120 0.02 " YES NO " Schwarz.Semi NOFully Coupled

Hydro(PPM) Kinetic BombPrompt

WW (1995) 11-40 0.00-0.02

19 (enuc) +

240 post(H-Ge)

NO NO CF88x1.7 LedouxSemiconv.Not Coupled

Hydro/PistonDelayed

RHHW(2002)

15-25 0.02 19 (enuc) +

700-2000 (adaptive)

(H-Pb)

YES NO Buchmann x 1.2

" "

UN (2002) 13-30150-270

0 240 coupled ?

NO NO CF85 Schwarz.Semi NONot Coupled

Hydro/Thermal BombDelayed

NH (1988)+TNH(1996)

13-25 0.02 ? NO NO CF85 " "

HMM (2004-2006)

9-120 0.00-0.04

network for advanced phases

YES YES NACRE Schwarz.OvershootingNot Coupled

NO

Present Status of the presupernova and explosion modelling of Massive Stars

Databases of Cross Sections

Experimental:

Caughlan et al. (1985)Caughlan & Fowler (1988)Angulo et al. (1999) NACREBao et al. (2000): (n,) reactions Iliadis et al. (2001): (p,) reactionsJaeger et al. (2001): 22Ne(,n)25MgKunz et al. (2001): 12C(,)16OFormicola et al. (2004) LUNA collaboration: 14N(p,)15O LENA collaboration: 14N(p,)15O

Theoretical:

Woosley et al. 1978Rauscher & Thielemann (2000) REACLIBFuller, Fowler & Newmann (1982,1985) (Weak)Oda et al. (1984) (Weak)Takahshi & Yokoi (1987) (Weak)Langanke & Martinez Pinedo (2000) (Weak)

O),(C 1612

Z=Z

Z=Z

Global Properties

Final Composition (for each solar mass returned to the ISM)

X=0.444 (f=0.64)Y=0.420 (f=1.47)Z=0.136 (f=6.84)

LC06

X=0.463 (f=0.65)Y=0.391 (f=1.42)Z=0.146 (f=7.30)

WW95

X=0.482 (f=0.65)Y=0.340 (f=1.42)Z=0.178 (f=8.90)

RHHW02

Z=Z

Strategies for improvements

Round Table and Comparison Among:

Evolutionary Codes (Assumptions, Numerical Algorithms, etc.)

Input Physics (EOS, Opacities, Cross Sections, Neutrino Losses, Electron Screenings, etc.)

Nuclear Network (extension, how it is included into the code)

Input Physics Repository

EOS, Opacities, Cross Sections, etc. (Tables and Codes)

Computation of Models under the same code setup

Additional comments welcome......

Pre/Post SN models and explosive yields available at http://www.mporzio.astro.it/~limongi