THE EFFECT OF ROTATION ON THE HYDROSTATIC AND EXPLOSIVE YIELDS OF MASSIVE STARS
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Transcript of THE EFFECT OF ROTATION ON THE HYDROSTATIC AND EXPLOSIVE YIELDS OF MASSIVE STARS
THE EFFECT OF ROTATION ON THE HYDROSTATIC AND
EXPLOSIVE YIELDS OF MASSIVE STARS
and
Alessandro ChieffiINAF – Istituto di Astrofisica e Planetologia Spaziali, Italy
Centre for Stellar and Planetary Astrophysics, Monash Univesity, [email protected]
Marco LimongiINAF – Osservatorio Astronomico di Roma, ITALY
Institute for the Physics and Mathematics of the Universe, [email protected]
HYDROSTATIC AND EXPLOSIVE YIELDS OF MASSIVE STARS
mass cut
Remnant Ejecta
HYDROSTATIC AND EXPLOSIVE YIELDS OF MASSIVE STARS
Element Production Site
N (14N) Hydrostatic H burningF (19F) Hydrostatic He convective shell
C (12C)O (16O)
Hydrostatic core He burning(16O partially modified by Cshell and Nex)
Ne (20Ne) Na (23Na)Mg (24Mg) Al (27Al)
Hydrostatic C convective shellPartially destroyed by Cx (23Na) and Nex (20Ne)Partially produced by Nex (24Mg,27Al)
P (31P) Nex
Cl (35Cl, 37Cl) Nex+Ox
K (39K) Ox
Sc (45Sc) Hydrostatic C convective shellNex+Ox
Si (28Si) S (32S)Ar (36Ar) Ca (40Ca)
Ox+Sii
V (51Cr)Cr (52Cr,52Fe)Mn (55Mn,55Co)
Sii
Ti (48Cr) Ox+Sii+SicFe (56Ni)Co (59Co,59Ni)Ni (58Ni,60Ni)
Sic
mass cut
Remnant Ejecta
HYDROSTATIC AND EXPLOSIVE YIELDS OF MASSIVE STARSHydrostatic Yields mainly depend on the presupernova evolution
(convective history, diffusive mixing, core masses, mass loss)
Each zone keeps track of the various central or shell, convective and/or ratidative, burning
C
C
CC
He
NeO
OO
Si
Si
HeH
Explosive Yields mainly depend on the presupernova chemical and density structure
Complete Si burning
Incomplete Si burning
Explosive O burning
Explosive Ne burning
Explosive C burning
No M
odifi
catio
n
NSE
Sc Ti FeCo Ni
QSE 1 Clusters
Cr V Mn
QSE 2 Cluster
Si S ArK Ca
Mg Al
P Cl
Ne Na
3700 5000 6400 11750 13400RADIUS (Km)
Mass-Radius relation, Ye profile, Chemical Stratification @ Presupernova Stage
Complete Si burning
Incomplete Si burning
Explosive O burning
Explosive Ne burning
Explosive C burning
No M
odifi
catio
n
NSE
Sc Ti FeCo Ni
QSE 1 Clusters
Cr V Mn
QSE 2 Cluster
Si S ArK Ca
Mg Al
P Cl
Ne Na
INTERIOR MASS
HYDROSTATIC AND EXPLOSIVE YIELDS 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 (ML & Chieffi 2003) and 5.0 (ML &
Chieffi 2006)- FULL COUPLING of: Physical Structure - Nuclear Burning -
Chemical Mixing (convection, semiconvection, rotation)- INCLUSION OF ROTATION:
- Conservative rotation law/Shellular Rotation (Meynet & Maeder 1997)
- Transport of Angular Momentum (Advection/Diffusion, Maynet & Maeder 2000)
- 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
FRANEC 6.0
(Chieffi & ML in prep.)
(Coupled and solved simultaneously)
(4th order 4 ODE soved by means of a relaxation method)or
INFLUENCE OF ROTATION ON CORE H BURNING
INFLUENCE OF ROTATION ON CORE H BURNING
Almost same H exhausted core @ core H depletion (exception for M=120 M)Shallower chemical profiles in rotating models due to rotationally induced mixing
Different path in the HR diagram different mass loss history Mass Loss does not scale monotonically with rotation
INFLUENCE OF ROTATION ON CORE H BURNING
H-rich envelope enriched by core H burning products
M≤60 M : Rotational mixing dominates
Rotational induced mixing beyond the He convective core
Reduced m-gradient barrier larger convective cores
INFLUENCE OF ROTATION ON CORE AND SHELL He BURNING
v=0 km/s
v=300 km/s
M≤60 M : Rotational mixing dominates
Rotational induced mixing beyond the He convective core
Reduced m-gradient barrier larger convective coresLarger CO coresContinuous inward mixing of fresh 4He fuel Lower 12C left over at core He depletion
INFLUENCE OF ROTATION ON CORE AND SHELL He BURNING
v=0 km/s
v=300 km/s
M≤60 M : Rotational mixing dominates
Rotational induced mixing beyond the He convective core
Reduced m-gradient barrier larger convective coresLarger CO coresContinuous inward mixing of fresh 4He fuel Lower 12C left over at core He depletionFormation of He convective shell in the region of variable He He convective shell hotter more 12C and 16O produced locally
Rotating and Non Rotating models show completely different structures
INFLUENCE OF ROTATION ON CORE AND SHELL He BURNING
v=0 km/s
v=300 km/s
M>60 M : Mass Loss dominates
Mass Loss uncovers the He core at the beginning of Core He burning
INFLUENCE OF ROTATION ON CORE AND SHELL He BURNING
v=0 km/s
v=300 km/s
M>60 M : Mass Loss dominates
Mass Loss uncovers the He core at the beginning of Core He burning
He convective core progressively recedes in mass and leaves a region of variable He
INFLUENCE OF ROTATION ON CORE AND SHELL He BURNING
v=0 km/s
v=300 km/s
M>60 M : Mass Loss dominates
Mass Loss uncovers the He core at the beginning of Core He burning
He convective core progressively recedes in mass and leaves a region of variable HeIn these stars this region is not due to the rotationally induced mixing but to the efficient mass loss that progressively erodes the He core
INFLUENCE OF ROTATION ON CORE AND SHELL He BURNING
v=0 km/s
v=300 km/s
M>60 M : Mass Loss dominates
Mass Loss uncovers the He core at the beginning of Core He burning
He convective core progressively recedes in mass and leaves a region of variable HeIn these stars this region is not due to the rotationally induced mixing but to the efficient mass loss that progressively erodes the He coreFormation of He convective shell in the region of variable He in both rotating and non rotating models
Rotating and Non Rotating models show similar structures
INFLUENCE OF ROTATION ON CORE AND SHELL He BURNING
v=0 km/s
v=300 km/s
ADVANCED BURNING STAGES: INTERNAL EVOLUTION OF ROTATING AND NON ROTATING STARS
Properties of the CO core at Core C-ignition
Differences progressively reduce with the initial mass
Rotating models show larger CO cores and smaller 12C mass fractions at core He depletion compared to the non
rotating ones
ADVANCED BURNING STAGES: INTERNAL EVOLUTIONFour major burning, 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…
v=0 km/s
v=0 km/s
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
burning occur.
Basic rule: the larger is the CO core, the lower is the 12C at core He exhaustion. the less efficient is the C burning shell, the lower is the
number of convective episodes
Si
PRESUPERNOVA STAR
The higher is the mass of the CO core (the lower is the 12C at the core He exhaustion ), the more compact is the structure at the presupernova
stage
v=0 km/sv=0 km/s
Less efficient C shell burning means stronger contraction of the CO core
ADVANCED BURNING STAGES: INTERNAL EVOLUTION OF ROTATING AND NON ROTATING STARS
Properties of the CO core at Core C-ignition
Differences progressively reduce with the initial mass
Rotating models show larger CO cores and smaller 12C mass fraction at core He depletion compared to the non
rotating ones
PRESUPERNOVA MODELS: ROTATING vs NON ROTATING STARS
....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)Presupernova rotating models appear much more compact compared to the non rotating ones and with larger Fe cores
Rotating models have a larger binding energy compared to the non rotating ones
PRESUPERNOVA MODELS: ROTATING vs NON ROTATING STARS
THE FINAL FATEHydrodynamical simulations based on induced explosions for Eexpl=1051 erg
(ML & Chieffi 2003, Chieffi & ML 2012 in prep)
Larger binding energies Larger fallback masses after the explosion Rotating models less efficient in polluting the ISM with heavy
elements
Difficult to compare the ejected masses in this case
In both cases no, or very few, heavy elements ejected for models with M>20 M
EJECTED MASSES: COMPARISONCo
mpa
rison
mad
e fo
r a fi
xed
amou
nt o
f 56 N
i eje
cted
• Differences confined with a factor of 2 for the majority of the elements
EJECTED MASSES: COMPARISONCo
mpa
rison
mad
e fo
r a fi
xed
amou
nt o
f 56 N
i eje
cted
• Differences confined with a factor of 2 for the majority of the elements• Overproduction of C and O in low-mass rotating models
EJECTED MASSES: COMPARISONCo
mpa
rison
mad
e fo
r a fi
xed
amou
nt o
f 56 N
i eje
cted
• Differences confined with a factor of 2 for the majority of the elements• Overproduction of C and O in low-mass rotating models• Overproduction of F in rotating models with mass 20-40 M
EJECTED MASSES: COMPARISONCo
mpa
rison
mad
e fo
r a fi
xed
amou
nt o
f 56 N
i eje
cted
• Differences confined with a factor of 2 for the majority of the elements• Overproduction of C and O in low-mass rotating models• Overproduction of F in rotating models with mass 20-40 M• Overproduction of Si-Sc elements in rotating models with mass ~ 20-25
M
EJECTED MASSES: COMPARISONCo
mpa
rison
mad
e fo
r a fi
xed
amou
nt o
f 56 N
i eje
cted
• Differences confined with a factor of 2 for the majority of the elements• Overproduction of C and O in low-mass rotating models• Overproduction of F in rotating models with mass 20-40 M• Overproduction of Si-Sc elements in rotating models with mass ~ 13-25
M• Overproduction of s-process elements in rotating models with mass 20-
40 M
Element
Production Site Ejected Mass Ratio
(Rot/No Rot)
Reason
C Hydrostatic Core and Shell He burning
~3-2 for M<30 M Larger CO cores/Hotter He convective shells(In spite of the lower 12C left by core He burning)
O Hydrostatic Core He burning
~5-2 for M<25 M Larger CO cores/Larger 16O left by Core He burning
F Hydrostatic He convective shell
~20 around M=30 M
Hotter He convective shell
Si-Sc Explosive burning ~2 for M<30 M More compact PreSN structure more mass synthesized by all the explosive burning
s-process
Hydrostatic Core He burning and Hydrostatic Convective C burning
~7 around M=30 M
Longer He burning lifetimesLarger He convective coresHotter C convective shell
EJECTED MASSES: COMPARISON
Rotating models produce more metals compared to the non rotating ones because of the larger CO cores and more
compact structures
ENRICHMENT OF THE INTERSTELLAR MEDIUM
Differences reduce with the mass
56Ni=0.1 M
PRODUCTION FACTORS
SUMMARY AND CONCLUSIONS
Influence of rotation on the presupernova evolution (from the point of view of the hydrostatic and explosive yields)
Negligible effect on the H exhausted core @ core H depletionLarger CO cores and smaller 12C mass fractions @ core He depletion Differences progressively reduced with the initial massPresupernova models more compact and with larger Fe cores Larger binding energiesLarger fallback masses less efficient enrichment of heavy elements for low explosion energiesDifferences in the final yields confined within a factor of ~2 for the majority of the elementsOverproduction of C and O more pronounced in the low-mass modelsOverproduction of Si-Sc elements in models with mass ~ 20-25 MOverproduction of F and s-process elements in models with mass ~ 20-40 MF and s-process elments distribution closer to the solar one in stars with mass ~ 25-40 M