0 1 2
3 45 6
7 8
9 10
11 12 13
14
15 16
17 18 19 20
21 22
23 24
25 26 27 28
29 30
31 32
33 34 35 36
37 38 39 4041
42 43 44
45 46 47 48
49 5051 52
5354 55
56
57 58
59
H (1)H e (2)L i (3 )
Be (4) B (5) C (6) N (7)
O (8) F (9)
N e (10)N a (11)
M g (12)A l (13)S i (14) P (15)
S (16)C l (17)
A r (18) K (19)
C a (20)Sc (21)
Ti (22) V (23)
C r (24)M n (25)
Fe (26)C o (27)
N i (28)C u (29)
Zn (30)G a (31)
G e (32)As (33)
Se (34)B r (35)K r (36)R b (37)
S r (38) Y (39)
Zr (40)N b (41)
M o (42)Tc (43)
R u (44)R h (45)Pd (46)Ag (47)
C d (48)In (49)
Sn (50)Sb (51)
Te (52) I (53)
Xe (54)
3 reaction++ 12C p process:
14O+ 17F+p17F+p 18Ne18Ne+ …
In detail:p process
Alternating (,p) and (p,) reactions:For each proton capture there is an (,p) reaction releasing a proton
Net effect: pure He burning
Mass known < 10 keV
Mass known > 10 keV
Only half-life known
seen
Measure: decay properties gs masses level properties rates/cross sections
Figure: Schatz&Rehm, Nucl. Phys. A,
Reaction rates:• direct measurements difficult• “indirect” methods:
• Coulomb breakup• (p,p)• transfer reactions stable beams and RIBS
Guide direct measurements Huge reduction in uncertainties If capture on excited states matters only choice
NSCL Set of experimentsuse (p,d) to determinelevel structure
ISOLTRAPRodriguez et al.NSCL Lebit
Bollen et al.
ANL CPTSavard et al.
Recent progress in mass measurements
JYFL Trap
Nuclear physics needed for rp-process:
0 12
3 45 6
7 8
9 10
11 12 13
14
15 16
17 18 19 20
21 22
23 24
25 26 27 28
29 30
31 32
33 34 35 36
37 38 39 4041
42 43 44
45 46 47 48
49 5051 52
5354 55
56
57 58
n (0) H (1)
H e (2)L i (3)
Be (4) B (5) C (6) N (7)
O (8) F (9)
N e (10)N a (11)
M g (12)A l (13)S i (14) P (15)
S (16)C l (17)
A r (18) K (19)
C a (20)Sc (21)
Ti (22) V (23)
C r (24)M n (25)
Fe (26)C o (27)
N i (28)C u (29)
Zn (30)G a (31)
G e (32)As (33)
Se (34)B r (35)K r (36)R b (37)
S r (38) Y (39)
Zr (40)N b (41)
M o (42)Tc (43)
R u (44)R h (45)Pd (46)Ag (47)
C d (48)In (49)
Sn (50)Sb (51)
Te (52) I (53)
Xe (54)
some experimental information available(most rates are still uncertain)
Theoretical reaction rate predictions difficult neardrip line as single resonances dominate rate:
Hauser-Feshbach: not applicable
Shell model: available up to A~63 but large uncertainties (often x1000 - x10000)
(Herndl et al. 1995, Fisker et al. 2001)
Need rare isotope beam experiments
• -decay half-lives• masses• reaction rates mainly (p,), (,p)
(ok)
(in progress)
(just begun)
Bishop et al. 2003 (TRIUMF)
H. Schatz
1) Direct Measurements
For p-captureonly 2 cases so far !
21Na + p 22Mg
2) First step: indirect techniques with low intensity rare isotope beams
Need RIA
Many developed at a number of facilities: (ANL, GSI, MSU, ORNL, RIKEN, Texas A&M, …)
Example: 32Cl + p 33Ar* 33Ar +
Resonant enhancement through states in 33Ar ?
Techniques with rare isotope beams
-rays from predicted 3.97 MeV state
Doppler corrected -rays in coincidence with 33Ar in S800 focal plane:
33Ar level energies measured:
3819(4) keV (150 keV below SM)3456(6) keV (104 keV below SM)
33Ar level energies measured:
3819(4) keV (150 keV below SM)3456(6) keV (104 keV below SM)
H. Schatz
NSCL Experiment: Clement et al. PRL 92 (2004) 2502
x10000 uncertainty
shell model only
reac
tion
rate
(cm
3/s
/mol
e)
temperature (GK)
x 3 uncertaintywith experimental data
stellar reaction rate
dPlastic
34Ar
33Arexcited
H. Schatz
Stellar Enhancement Factor
SEF = stellar capture rate
ground state capture rate
this work
NON Smoker
direct measurement of this rate is not possible – need indirect methods SEF’s should be calculated with shell model if possible
1+
2+90 keV
3.364
3.456
3.819
4.190
33Ar
32Cl
5/2+
7/2+
5/2+
1/2+MeV
3.343
Dominantresonance
H. Schatz
Mass ejection in X-ray bursts ? Weinberg, Bildsten, Schatz 2005T
empe
ratu
re (
K)
Column density (g/cm2)
Initial ra
diative profile
wind
?
Winds can eject <1% of accreted massDoes convection zone reach into theouter layers that get blown off ???
Wind ejects ashes in radius expansion bursts for wide range of parameters
surface
Neutron star interior
wind
dept
h
H. Schatz
Reaction flow during burst rise in pure He flash
12C
13N
16O
slow
(p,)
(,p)
12C() bypass
Need protons as catalysts(~109 are enough !)
Source: (,p) reactionsand feedback through bypass
Increases risetime Triggers late reexpansion of convection zone enhances production of heavy elements vs. carbon
H. Schatz
Composition of ejected material
32S28Si
Weak p-captureon initial Fe seed
Observable with current X-ray telescopes
in wind on NS surface
as spectral edges Explanation for enhanced Ne/O ratio in 4U1543-624, 4U1850-087, … ??? (ratios ~1 – ISM 0.18)
Observable with current X-ray telescopes
in wind on NS surface
as spectral edges Explanation for enhanced Ne/O ratio in 4U1543-624, 4U1850-087, … ??? (ratios ~1 – ISM 0.18)
Neutron star surface
ocean
Innercrust
outercrust
H,He
gasashes
~ 20m, =109 g/cm3
superburst
H. Schatz
Step 2: Deep ocean burning: Superbursts
long duration through longer radiation transport long time to accumulate means long recurrence time more material means more total energy by same factor for same MeV/u)
Accreting Neutron Star Surface
fuel
ashesocean
Innercrust
outercrust
H,He
gas
core
Radiation transport
~1 m
~10 m
~100 m
~1 km
10 km
Thermonuclear H+He burning(rp process)
~10s
Deep burning ?
~hours
~ x1000 longer burst duration~ x1000 longer recurrence time~ x1000 more energy
H. Schatz
The origin of superbursts – Ashes to Ashes
0 24
68
10 12
14
16 18
20 2224
26 2830
32
3436
3840
42
4446
48
50 52
5456
5860
6264 66
68
70
0
2
4
6
8
10
12
14
16
18
20
22
24
26
28
30
32
34
36
38
40
42
44
46
48
50
52
54
Tim e:Tem perature:
1.041e-04 s0.850 G K
0 24
68
10 12
14
16 18
20 2224
26 2830
32
3436
3840
42
4446
48
50 52
5456
5860
6264 66
68
70
0
2
4
6
8
10
12
14
16
18
20
22
24
26
28
30
32
34
36
38
40
42
44
46
48
50
52
54
Tim e:Tem perature:
1.076e+03 s6.607 G K
Burst peak (~7 GK)
~ 45% Energy
~ 55% Energy
Carbon can explodedeep in ocean (Cumming & Bildsten 2001)
(Schatz, Bildsten, Cumming, ApJ Lett. 583(2003)L87
Ashes to ashes – the origin of superbursts ?
Puzzle:The ocean is too cold ignition about every 10 years instead of every year as observed
Energy generation everywhere else in comos:• Stars• X-ray bursts, Novae
Energy generation in Superbursts(plus C->Ni fusion)only place in cosmos ? And nuclear power plants
on earth
Neutron star surface
ocean
Innercrust
outercrust
H,He
gasashes
ashes
~ 25 – 70 m =109-13 g/cm3
H. Schatz
Step 3: Crust burning
Surface of accreting neutron stars
Neutron star surface
Ocean (palladium? Zinc?)
Innercrust
Crust of rare isotopes
gas
D. Page
X-ray bursts
1m
10m
Hydrogen, Helium
ashes
superbursts
34Ne
1.5 x 1012 g/cm3
68Ca
1.8 x 1012 g/cm3
106Ge
56Ar2.5 x 1011 g/cm3
4.8 x 1011 g/cm3
72Ca 4.4 x 1012 g/cm3
rp-ashes
106Pd
56Fe
Haensel & Zdunik 1990, 2003Gupta et al. 2006
Known mass
Crust processes
Known mass
Crust processes
Reach of next generation Rare Isotope Facility FRIB
(here MSU’s ISF concept)(mass measurements)
Reach of next generation Rare Isotope Facility FRIB
(here MSU’s ISF concept)(mass measurements)
Recent massmeasurements
at GSI(Scheidenberger et al.,
Matos et al.)
Recent massmeasurements
at GSI(Scheidenberger et al.,
Matos et al.)
Recent TOF massmeasurements
at MSU(Matos et al.)
Recent TOF massmeasurements
at MSU(Matos et al.)
Recent massmeasurementsat ISOLTRAP(Blaum et. al.)
Recent massmeasurementsat ISOLTRAP(Blaum et. al.)
Q-valuemeasurement
at ORNL(Thomas et al. 2005)
Q-valuemeasurement
at ORNL(Thomas et al. 2005)
Recent massmeasurements
at Jyvaskyla(Hager et. al. 2006)
Recent massmeasurements
at Jyvaskyla(Hager et. al. 2006)
Excitation energyof main transition
NEW JINA Result: S. Gupta, E. Brown, H. Schatz,K.-L. Kratz, P. Moeller 2007
Electron capture into excitedstates increases heatingby up to a factor of ~10
NEW JINA Result: S. Gupta, E. Brown, H. Schatz,K.-L. Kratz, P. Moeller 2007
Electron capture into excitedstates increases heatingby up to a factor of ~10
Increasedheating
superbursts
rp-ashes
Former estimate
New heatingenhanced by x 5-6
Heats entire crust and increases ocean temperature from 480 Mio K to 500 Mio K
Enhanced crust heating
Impact of new crust modeling on superbursts
Can the additional heating from EC into excited states make the crust hot enough to get the superburst ignition depth in line with observations ?
Almost:
Without excited states
Igni
tion
dept
h
Mass number of crust composition (pure single species crust)
Inferred fromobservations
KS 1731-260 (Wijands 2001)
Bright X-ray burster for ~12 yrAccretion shut off early 2001
Is residual luminosity coolingneutron star crust ? If yes: probe neutron star !
H. Schatz
Observables: transients in quiescence
Low crust conductivity, normal core cooling
High crust conductivity, enhanced core cooling
(Ouellette & Brown 2005)(Rutledge 2002)
H. Schatz
Comparison with observations during quiescence
High crust conductivityEnhanced core cooling
Low crust conductivityNormal core cooling
Low crust conductivityEnhanced core cooling
High crust conductivityNormal core cooling
(data from Wijnands 2004)
but: a superburst has been observed from KS 1731-260 this indicates a hotter crust and low crust conductivity
(Brown 2004)
but: a superburst has been observed from KS 1731-260 this indicates a hotter crust and low crust conductivity
(Brown 2004)
M. Ouellette
H. Schatz
Superbursts as probes for NS cooling
Superburst ignition depth (Ed Brown, to be published)(for accretion rate of 3e17 g/s and X(12C)=0.1)
Recurrence time depends on crust conductivity and core cooling Observations require LOW conductivity and no enhanced cooling (incl. KS1731-260)
Recurrence time depends on crust conductivity and core cooling Observations require LOW conductivity and no enhanced cooling (incl. KS1731-260)
“regular” core cooling
“enhanced” core cooling
Low crust conductivity
High crust conductivity
27 yr
5.2 yr
1.4 yr3.1 yr
Recurrence times(observed ~ 1yr)