“radionuclides and gamma-ray line astronomy”
TRANSCRIPT
INTEGRAL School, Les Diablerets (CH) April 2000 Roland Diehl
INTEGRAL School, Les Diablerets (CH), March/April 2000
“Radionuclides and Gamma-Ray Line Astronomy”“Radionuclides and Gamma-Ray Line Astronomy”
Invited LecturesInvited Lecturesby
Roland DiehlMPE Garching
•• Part I:Part I: Gamma-Rays and NucleosynthesisGamma-Rays and Nucleosynthesis–– Nucleosynthesis ProcessesNucleosynthesis Processes
–– Radioactive DecayRadioactive Decay
–– Cosmic Nucleosynthesis SitesCosmic Nucleosynthesis Sites
•• Part II:Part II: Observed Cosmic RadioactivitiesObserved Cosmic Radioactivities–– SupernovaeSupernovae
–– Diffuse Radioactivities & Various ConnectionsDiffuse Radioactivities & Various Connections
INTEGRAL School, Les Diablerets (CH) April 2000 Roland Diehl
Nucleosynthesis Processes: Reading the AbundancesNucleosynthesis Processes: Reading the Abundances
� Observed Abundances Show Striking Patterns:�Abundances Vary Much for Light Elements uf to ~ Fe-Group,
are ~Similar Order of Magnitude for Elements >65�H and He are by far the Most Abundant Elements�Li, Be, B Fall in a Deep Minimum (9 Orders of Magnitude)�Elements C....Ca Show Exponentially-Declining Abundances�There is a Abundance Clear Peak Around Fe�Upon Close Look, There are Two Local Peaks Around Ba and Pb
� Nuclear Processes / Reactions “Connect” NeighbouringIsotopes (Reactions −−−−>>>> n, p, or αααα capture or stripping)
=>�Big-Bang Nucleosynthesis
Formed H and He�Nuclear Equilibrium Burning
Formed Fe Elements�An “αααα-Process” Plays a Leading
Role for Elements C...Ca�Elements Heavier Than Fe
Formed from Fe Elements
Standard Abundances
Bi
Th
PbPt
KrGe
Zn
Ni
Fe
CaAr
SSi
NeC
O
N
Ti
V
Sc
F
Be
LiB
H
Dy
Eu
Ba
Sr
He
0
2
4
6
8
10
12
0 20 40 60 80 100
Element (Z)
Abundance
(lo
g N
, H
=12)
R.Diehl_696_abundnc
fragile elements
αααα elements
...Fe group elements
(most tightly bound)
tighter-bound elements(closed shells)
INTEGRAL School, Les Diablerets (CH) April 2000 Roland Diehl
Cosmic Matter CompositionCosmic Matter Composition
Matter Composition
76
24
8.00E-08
70.683
27.431
1.886
0
20
40
60
80
H He Metals
Mas
s F
ract
ion
(%
)
after Big Bang Nucleosynthesis
in Solar System
R.Diehl / '96 abundnc
INTEGRAL School, Les Diablerets (CH) April 2000 Roland Diehl
Abundances in Different Parts of the UniverseAbundances in Different Parts of the Universe
Abundances: Solar vs. Supernova Ejecta
H
CN
O
F
Ne
Na
Mg
Al
Si
P
S
Ar Ca
Sc
Ti
Fe
Ni
-3
-1
1
3
5
7
9
11
5 10 15 20 25 30 35
Element (atomic number)
Abundan
ce (lo
g N
; Si=
6)
solar
SN87A
rod696abundnc
INTEGRAL School, Les Diablerets (CH) April 2000 Roland Diehl
Circulation of Matter Circulation of Matter
interstellarmedium
densemolecular
cloudscondensation
star formation (~3%)
mixing
SN explosion
106-1010 y
102-106y
108 y
rod0795 matter
compactremnant
(WD,NS,BH)
M~104...6 Mo
SNIa
~90%
infalldustdust
SNR's &hot
bubbles
winds
starsM > 0.08 Mo
stars
Galactic
halo
INTEGRAL School, Les Diablerets (CH) April 2000 Roland Diehl
Radioactivity Traces from NucleosynthesisRadioactivity Traces from Nucleosynthesis
• Long-Lived Isotopes DecayOutside Nucleosynthesis Site
• Radioactive-Decay Gamma-Rays Can Be ObservedThrough Gamma-RayTelescopes
• Isotopic Ratios Can BeObservedin Cosmic Rays, MolecularLines, Stellar Surfaces, ...
• Isotopic-Ratio ModificationsCan Be Measuredin Meteorites (Solar Material,but also Interstellar Grains)
p n
γ
26Al, 44Ti, 56Co, 57Co
INTEGRAL School, Les Diablerets (CH) April 2000 Roland Diehl
Stellar Classification and Radiation OriginStellar Classification and Radiation Origin
• Spectral Classification Encodes Temperature• Plasma Radiation Mechanism Depends on Temperature
�Molecules and Dust�Neutral Atoms� Ionized Atoms
O B A F G K M R N SO B A F G K M R N S Spectral ClassSpectral Class
spectrallineintensity
spectrallineintensity
molecules (T,O,..)
ionized .... neutral metals
hydrogenionized .... neutral helium
after Abell ‘64
INTEGRAL School, Les Diablerets (CH) April 2000 Roland Diehl
Radioactive DecayRadioactive Decay
26Al26Al 26Mg26Mgm 0.228 MeV (T ~ 4 108K)
γγγγ2.938 MeV( 0.3 % )*
e- - captureββββ+ - decay ( 97.3 % )
e- - capture ( 2.7 % )
ββββ+ - decay ( 100 % )
γγγγ1.130 MeV ( 2.4 % )*
γγγγ1.809 MeV ( 99.7 % )* γγγγ1.809 MeV ( 99.7 % )*
ττττ = 9.15 sττττ = 1.04 106 y
2+
2+
0+
0+5+
p n
γ
Al
Mg
Mg
INTEGRAL School, Les Diablerets (CH) April 2000 Roland Diehl
Studies of NucleosynthesisStudies of Nucleosynthesis
• Gamma-Rays from Radioactive Decays Relate Directly to Isotopic Abundance• Different Isotopes Probe Different Parameters of Nucleosynthesis Sites
. .
NucleosynthethisEvent
• MeteoriticStudies
• Atomic Lines inPhotosphere &Corona (opt,UV, X)
• Bolometric Lightin DifferentFrequency Ranges(Comptonized,Thermalized, Dust)
• Gamma-Ray Linesfrom RadioactiveIsotopes
INTEGRAL School, Les Diablerets (CH) April 2000 Roland Diehl
Objectives of Radioactivity Gamma-Ray Astronomy:Objectives of Radioactivity Gamma-Ray Astronomy:Relevant IsotopesRelevant Isotopes
Isotope Decaytime Decay Chain γγγγ -Ray Energy (keV)
7Be 77 d 7Be →→→→ 7Li* 478
56Ni 111 d 56Ni →→→→ 56Co* →→→→56Fe*+e+ 847, 1238
57Ni 390 d 57Co→→→→ 57Fe* 122
22Na 3.8 y 22Na →→→→ 22Ne* + e+ 1275
44Ti 89 y 44Ti→→→→44Sc*→→→→44Ca*+e+ 1157, 78, 68
26Al 1.04 106y 26Al →→→→ 26Mg* + e+ 1809
60Fe 2.0 106y 60Fe →→→→ 60Co* 1173, 1332
e+ …. 105y e++e- →→→→ Ps →→→→ γγγγγγγγ.. 511, <511
INTEGRAL School, Les Diablerets (CH) April 2000 Roland Diehl
COMPTEL Detections of RadioactivityCOMPTEL Detections of Radioactivity
Gamma-Ray Line at 1.809MeV
Attributed to 26Al Decay(Decay Time ττττ ~ 1 MioYears)
Detected and Mapped in the Full Sky
Gamma-Ray Line at 1.157MeV
Attributed to 44Ti Decay(Decay Time ττττ ~ 89 Years)
Detected from317-y-old SN Cas A at 3.4 kpc
SRC Dataset ID: MPE-RFR-20663
Sky circle 1 centered at
Longitude .....: 111.70 deg
Latitude ......: -2.10 deg
with radius 2.00 deg
EHA=0-180 deg;
Number of selected events: 21253
Sky circle 2 centered at
Longitude .....: ???.70 deg
Latitude ......: >40.10 deg
with radius 5.00 deg
chi sq.=36.33, 43 d.o.f.
Number of selected events: 2650
Cas A COMPTEL Phase 1-5
Energy (keV)
Cou
nts
/ bi
n
800 1000 1200 1400 1600 1800
-100
0
100
200
Gamma-Ray Lines at 0.847 and 1.238 MeVAttributed to 56Co Decay(Decay Time ττττ ~ 111 Days)
Detected (marginally) from SN 1991T at ~17MpcDistance
INTEGRAL School, Les Diablerets (CH) April 2000 Roland Diehl
Gamma-Ray Line Astrophysics - The GoalsGamma-Ray Line Astrophysics - The Goals
• Utilize / Open a New Astronomical Window– Penetration of Gamma-Rays– Unique/Direct Inference of Isotope Abundances
• Calibrate Engines of Stars / Novae / Supernovae– Nuclear Reactions as Root Energy Source– Radio-Isotopes Emit Gamma-Ray Lines
• Study Parameters of Nucleosynthesis Sites– Identify Operating Nuclear Reaction Chains per Site
– Constrain Environmental Par’s (T,ρ,τconv)
• Study Energetic-Particle Processes– Acceleration Mechanisms (Solar Flares)– Cosmic Ray Source Regions (Nuclear-Excitation
Lines)
INTEGRAL School, Les Diablerets (CH) April 2000 Roland Diehl
Cosmic RadioactivitiesCosmic Radioactivities
Goals:� Understand the Physical Processes which Shaped the
Pattern of Abundances in (different parts of) the Universe� Provide Complementary Measurements on Cosmic Sites of
Nucleosynthesis
Standard Abundances
Bi
Th
PbPt
KrGe
Zn
Ni
Fe
CaAr
SSi
NeC
O
N
Ti
V
Sc
F
Be
LiB
H
Dy
Eu
Ba
Sr
He
0
2
4
6
8
10
12
0 20 40 60 80 100
Element (Z)
Abu
ndan
ce (
log
N,
H=1
2)
R.Diehl_696_abundnc
fragile elements
αααα elements
...Fe group elements
(most tightly bound)
tighter-bound elements(closed shells)
INTEGRAL School, Les Diablerets (CH) April 2000 Roland Diehl
The Stable Isotopes of MatterThe Stable Isotopes of Matter
Isotope Chart
0
20
40
60
80
100
120
140
0 20 40 60 80 100 120 140 160 180
No. of Neutrons
No. of
Pro
ton
s
rod696abundnc
INTEGRAL School, Les Diablerets (CH) April 2000 Roland Diehl
Nuclear Reactions in Cosmic NucleosynthesisNuclear Reactions in Cosmic Nucleosynthesis
• Strong Interactions�p Capture�n Capture�Heavy-Ion Reactions�Resonances
� Nuclear Force Range: ~10-15 m = fm� Reaction Times 10-16...10-22 s� Coulomb Repulsion -> Tunneling (‘Gamov Peak’)� Stellar Reaction Cross Sections Interpolated from
Measurements at Lab. Energies (‘astrophysical S-Factor’)
• Weak Interactions�n + ννννe �������� p + e- ‘ββββ Decays’
� ‘Slow’ Compared to Strong Reactions� log (ft) values with (t >> 10-16s)
INTEGRAL School, Les Diablerets (CH) April 2000 Roland Diehl
The Nuclear Binding Force in Different NucleiThe Nuclear Binding Force in Different Nuclei
Nuclear Binding Energy
-100.00
-80.00
-60.00
-40.00
-20.00
0.00
20.00
40.00
0 50 100 150 200 250
No of Nucleons
Bin
din
g E
ner
gy (M
-A;
12C
.=0
.0)
INTEGRAL School, Les Diablerets (CH) April 2000 Roland Diehl
Cosmic Nucleosynthesis EnvironmentsCosmic Nucleosynthesis Environments
Nuclear Burning Requirements:• <σσσσv> * Q ≥≥≥≥ Local Cooling Rate=>• Dense & Hot Environments
for a Stellar Mass Range of 1-30 Mo:
• Nuclear Burning in Stellar Cores andShells (top)
• Nuclear Burning in Explosive Sites(bottom)
• Gamov Windows (righthand side)
INTEGRAL School, Les Diablerets (CH) April 2000 Roland Diehl
Elementary Nuclear-Reaction CyclesElementary Nuclear-Reaction Cycles
• H Burning: p-p Chains
1H
p2D
p
3He
3He
γ
4He
1H
1H
++++ ++
4He
++
7Be
γ
e- 7Lie+
ν ++ν
++
++p
4He
4He
1H8B
γ
8Be
e+
ν
4He
4He
PP I
PP II
PP III
INTEGRAL School, Les Diablerets (CH) April 2000 Roland Diehl
Elementary Nuclear Burning CyclesElementary Nuclear Burning Cycles
• H Burning: CNO Cycle
12C
13N
13C 14N 17O 18F
19F 20Ne
15O 17F
15N 16O 18O
p,γγγγ p,αααα p,γγγγ
p,γ γγγ
p,γ γγγ
e+ν ννν
e+ν ννν
p,γ γγγ
e+ν ννν
p,αααα
p,αααα
p,αααα
e+ν ννν
p,γγγγp,γγγγ
I II IIIIV
p,γγγγ
slow!
slow!
slow!!!
�Net Burning towards 14N�
12C/13C ~4 (SAD:89)
INTEGRAL School, Les Diablerets (CH) April 2000 Roland Diehl
Elementary Nuclear-Burning CyclesElementary Nuclear-Burning Cycles
• He Burning: 3αααα Cycle
4He + 4He 8Be
8Be + 4He 12C* 12C* 12C
�Lifetime 8Be ~ 7 10-16 s�
8Be(αααα,,,,γγγγγγγγ)12C through Excited Level at 278 keV+ (Salpeter, Hoyle)
� ε ε ε ε ~ T840 −−−−>>>> He Flash
8Be + 4He7.366
12C 0+0.0
12C 2+4.43
12C 0+7.64
12C 3-9.64
INTEGRAL School, Les Diablerets (CH) April 2000 Roland Diehl
Elementary Nuclear-Burning CyclesElementary Nuclear-Burning Cycles
• He Burning: 3αααα Cycle
4He + 4He 8Be
8Be + 4He 12C* 12C* 12C
�Lifetime 8Be ~ 7 10-16 s�
8Be(αααα,,,,γγγγγγγγ)12C through Excited Level at 278 keV+ (Salpeter, Hoyle)
� ε ε ε ε ~ T840 −−−−>>>> He Flash
8Be + 4He7.366
12C 0+0.0
12C 2+4.43
12C 0+7.64
12C 3-9.64
INTEGRAL School, Les Diablerets (CH) April 2000 Roland Diehl
26Alm
28Si26Si
(p,γγγγ)
(p,γγγγ)(p,γγγγ)
(p,γγγγ)(p,γγγγ)
(p,γγγγ)
ββββ+
ββββ+(7.2s)
9.2 s ββββ+
1.07 106 y
ββββ+
(p,αααα)
(p,αααα)
(n,p)
23Na
26Al
27Si
27Al
26Mg25Mg24Mg
25Al
2626Al Nucleosynthesis: Example of a Cosmic Reaction Network,Al Nucleosynthesis: Example of a Cosmic Reaction Network,Common for Intermediate-Mass IsotopesCommon for Intermediate-Mass Isotopes
INTEGRAL School, Les Diablerets (CH) April 2000 Roland Diehl
Production of Elements Beyond the Fe Peak:Production of Elements Beyond the Fe Peak:r-Process and s-Processr-Process and s-Process
• Seed Nuclei (~ Fe-Group Elements) Capture Neutrons
• ββββ Decays Establish Final Abundances� n capture faster than ββββ-decay −−−−>>>> r-process� n capture slower than ββββ-decay −−−−>>>> s-process
30
40
50
60
70
60 70 80 90 100
No. of Neutrons
No.
of
Pro
ton
s
s-only
r-only
N=Z
r-process path
βββ β-d
ecays
s-process path
INTEGRAL School, Les Diablerets (CH) April 2000 Roland Diehl
Process Site Key Isotopes
� H burning pp chains, CNO cycle all stars 4He;13C 14N
� He burning 3-αααα process most stars 12C 16O 20Ne 24Mg
� αααα-process hot burning with excess αααα’s mass. stars, SNae 20Ne 24Mg 28Si 32S 36Ar 40Ca
� Fe-group elements:e-process thermal equilibrium (NSE) SNae (thermonucl) Fe-group elements (~56)
� n-rich heavy elements:s-process n capt. slower than ββββ-decay He-burning stars elements >62 close to
valley of stabilityr-process n capt. faster than ββββ-decay SNae (CC) elements >62, also further
from valley of stability� spallation energetic heavy-ion collision ISM / cosmic rays 6Li 8,9Be 10,11B
� p-rich isotopes:rp-process hot H burning novae p-rich elements <Fe groupp-process n depletion ((((‘γγγγ-process’) ?? p-rich elements >62
� ‘normal’ nuclear reactions [(n,γγγγ), (p,γγγγ), (αααα,,,,γγγγ)...] stars, SNae in-between elements� νννν-process νννν excitation of nuclei SNae (CC) various contributions� x-process unknown; make up for ?? (2H Li Be B)
BBN+Spallation definiency
Nucleosynthesis: “Processes”,“Categories”Nucleosynthesis: “Processes”,“Categories”
INTEGRAL School, Les Diablerets (CH) April 2000 Roland Diehl
Objectives of Radioactivity Gamma-Ray Astronomy:Objectives of Radioactivity Gamma-Ray Astronomy:Nucleosynthesis EnvironmentsNucleosynthesis Environments
Stellar Cores & Shells Nuclear Reaction Networks (T),
Hydrostatic Burning & Convection
Products only from SN & Wind
WR and AGB Stars Convection Enhanced, Wind Feeds
ISM with Products; HBB
Novae Hot Hydrogen Burning
Core Collapse Supernovae Shockfront Burning in Shell-Like Star
Supernovae Type Ia NSE Processing of Stellar Remnant
Interstellar Medium ~Laboratory-like Nuclear Reactions
⇒ Variety of Nucleosynthesis Conditions(Temp., Dens.) and Timescales
INTEGRAL School, Les Diablerets (CH) April 2000 Roland Diehl
Objectives of Radioactivity Gamma-Ray Astronomy:Objectives of Radioactivity Gamma-Ray Astronomy:Different Objectives per Isotope:Different Objectives per Isotope:
7Be: Novae Nova Convection & Nucleosynthesis
56Ni & 57Ni: SN SN Nucleosynthesis & Envelope
Structure
22Na: Novae Binary Evolution, Nucleosynthesis
44Ti: SN SN Mass Cut, SN Rate
26Al, 60Fe, (e+) Galaxy Nucleosynthesis (Location, Rate)
INTEGRAL School, Les Diablerets (CH) April 2000 Roland Diehl
Massive Star Core StructureMassive Star Core Structure
(25 Mo)
1H, 4
He
12C, 16
O
4He
16O, 20Ne, 24
Mg
28Si, 32
S
16O, 24
Mg, 28Si
Si−−−−>>>>Fe,Ni
O−−− −>>> >Si
Ne−−− −>>> >O,Mg
C−>
−>−>
−>Ne,Mg
He−−− −>>> >C,O
H−−− −>>> >He
9.9 9.5 8.9 8.7 8.3 7.0 log T
0.08
0.02
0.15
0.05
0.1
0.6
∆ ∆∆∆m/M
��������
��������
����
����
INTEGRAL School, Les Diablerets (CH) April 2000 Roland Diehl
ννν
νν
ννν
ννννν
νν
ν
ν
ν
ν
ν
ν
νν
ν
GravitationalCore Collapse
SupernovaShock Wave
Shock RegionExplosive Nucleosynthesis
Proto-Neutron StarNeutrino Heating
of Shock Region from Inside
Shell-StructuredEvolved Massive Star
Core CollapseCore CollapseSupernova ModelSupernova Model
INTEGRAL School, Les Diablerets (CH) April 2000 Roland Diehl
Core Collapse Supernova EvolutionCore Collapse Supernova Evolution
• Phases and Time Scales– Core Collapse– Convection in Inner Zones 50 ms .....– Shock at Fe/Si Interface 100 ms– End of NSE burning 250 ms– End of Convection 400 ms– End of Nuclear Burning 500...700 ms– Explosive-Product Shell/Shock Detachment– Shock at C-O/He Interface 1..5 s– Rayleigh-Taylor Instability Development 1...50 s– Reverse-Shock Deceleration of Ejecta 50..100 s– Beginning of Ballistic Clump Motions 100 s
INTEGRAL School, Les Diablerets (CH) April 2000 Roland Diehl
Gamma-Rays from Supernovae and Their RemnantsGamma-Rays from Supernovae and Their Remnants
• SN Nucleosynthesis −>−>−>−> Radioactivity LineEmission
• SNR Particle Acceleration −>−>−>−> Continuum Emission• SN Blast Wave / ISM Impact −>−>−>−> other Characteristic
Emission• Luminosity Evolution (sketch) in Different Radiation Types:
10 100 1000 10000 105
SN:Optical,~X,~γγγγ(57Co)
γγγγ-Rays 44Ti (ττττ~90y)
γγγγ-Rays 26Al (ττττ~106y)optical
X-ray
Radio,~nonthermal X, γγγγ-rays
SNR Age (years)
Log L
INTEGRAL School, Les Diablerets (CH) April 2000 Roland Diehl
Gamma-Ray Lines from NovaeGamma-Ray Lines from Novae• Nova = Thermonuclear Runaway in
White-Dwarf Shell Accumulated fromLow-Level Accretion in Binary System
• dM/dt~10-9 Mo/y ; Maccr~5 10-5 Mo ; Mejected ~2 10-4 Mo
• ~30% Ne-rich Novae, others CO Novae
• Hot H Burning at T>108K−>−>−>−> p-Capture on CNOSeeds
• Gamma-Ray Sources:� ββββ+ Radioactivity Iγγγγ~1 10-2 ph cm-2 s-1 @1kpc�
7Be (from 3He(αααα,,,,γγγγ))Iγγγγ~2 10-6 ph cm-2 s-1 @1kpc�
22Na (from 20Ne(p,γγγγ)) Iγγγγ~4 10-6 ph cm-2 s-1 @1kpc�
26Al (from 25Mg(p,γγγγ)) Iγγγγ~1 10-10 ph cm-2 s-1 @1kpc
2
1
3
Issues:� Dredge-Up from WD� TNR Rise Time� MWD, Maccr
� Mej
� ....� Need CLOSE Nova� Need Early Exposure
0.1 1 10
Optical (arb.norm.)
1.3 MeV γγγγ-Rays 22Na (ττττ~3.75y)
Nova Age (months)
Log L
0.01
478 keV γγγγ-Rays 7Be (ττττ~77d)
511 keV γγγγ-Rays (b+decay)