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Classical Novae at the Crossroads of Astrophysics, Nuclear Physics and Cosmochemistry
Jordi José Dept. Física i Enginyeria Nuclear, Univ. Politècnica de Catalunya (UPC)
& Institut d’Estudis Espacials de Catalunya (IEEC), Barcelona
Moderate rise times (<1 – 2 days): 8 – 18 magnitude increase in brigthness LPeak ~ 104 – 105 L Stellar binary systems: WD + MS (often, K-M dwarfs) Recurrence time: ~ 10 yr (RNe) – 105 yr (CNe) Frequency: 30 ± 10 yr-1
[Obs.; ~ 5 yr-1]
E ∼ 1045 ergs
Mass ejected: 10-4 – 10-5 M
(~103 km s-1)
Novae have been observed in all λ (detected in γ-rays for E>100 MeV)
J. José Classical Novae
Theoretical Astrophysics
Observational Astronomy
Nuclear & Atomic Theory
Nuclear Experiments
Conservation eqs. Hydrodynamics Energy transport
Shell model Optical potentials Plasma properties
Reaction rates, EOS, opacities...
Astrophysical Models
Cosmochemistry
Spectroscopy, photometry
Observables: light curves, spectra, abundances...
~1 – 10 μm
~10 m
J. José Classical Novae
J. José
Current Challenges for Classical Novae
Classical Novae
• The amount of mass ejected predicted by 1-D models is somewhat smaller than that *inferred* observationally
• The mixing mechanism at work at the core-envelope interface during nova outbursts is not fully understood
H He
Li Be B C
0 1 2
3 4 5
6 7
8 9 10
11
N O
F Ne
Na Mg Al
Si P
S Cl Ar
K Ca
N
Z 12
13 14
15 16
17 18 20 19
T = 1 x 107 K
Model 1.35 M (50% ONe enrichment)
(p,γ)
(p,α) (β+)
Log (Reaction Fluxes) : -2 : -3 : -4
: -6 : -5
: -7
T = 3.2×108 K ρ = 5.1×102 g cm-3
εnuc = 4.3×1016 erg g-1 s-1
ΔMenv = 5.4×10-6 M
Endpoint ~ Ca No heavy metals produced!
Negligible contribution from any (n,γ) or (α,γ) reaction (that also applies to 15O(α,γ)!)
Main nuclear path close to the valley of stability, and driven by (p,γ), (p,α) and β+ interactions
Tpeak
Fuel (H) is not fully consumed in the explosion
T
T
T
T
T
T
ρ
ρ
ρ
ρ
ρ
ρ ψ
ψ
ψ
ψ
Tbase = 3×107 K
JJ (2014), in preparation
Degeneracy Lifting
Nuclear Uncertainties
Main nuclear uncertainties: [18F(p,α)15O, 25Al(p,γ)26Si, 30P(p,γ)31S]
J. José Classical Novae Nuclear Symphony || Observational Constraints || Multidimensional Models
See talks, this afternoon by: L. Sergi [17O(p, α)] M. Gulino [18F(p, α)] W. Richter [25Al(p, γ)]
J. José
V838 Her
Classical Novae Nuclear Symphony || Observational Constraints || Multidimensional Models
Andrëa et al. (1994)
PW Vul 1984 H He C N O Ne Na-Fe Z Observation 0.47 0.23 0.073 0.14 0.083 0.0040 0.0048 0.30 Theory 0.47 0.25 0.073 0.094 0.10 0.0036 0.0037 0.28 (JJ & Hernanz 1998)
J. José Classical Novae Nuclear Symphony || Observational Constraints || Multidimensional Models
Observational Constraints
-400
-200
0
200
-200 0 200 400 600 800 1000 1200δ30Si/28Si (‰)
Mainstream
Y grainsX grainsA+B grains
Nova grains (Graphite)Nova grains (SiC)Z grains
Solar
AF15bC-126-3
AF15bB-429-3
KFC1a-551
KJGM4C-311-6
KJGM4C-100-3
1E+0
1E+1
1E+2
1E+3
1E+4
1E+0 1E+1 1E+2 1E+3 1E+412C/13C
Mainstream ~93%A+B grains 4-5%
Nova grains (graphite)Nova grains (SiC)Z grains ~1%Y grains ~1%X grains ~1%
Solar
KJGM4C-311-6
KJGM4C-100-3
KJC112 AF15bC-126-3
KFC1a-551
KFB1a-161
J. José
Presolar Grains
Classical Novae Nuclear Symphony || Observational Constraints || Multidimensional Models
* 14,15O, 17F (13N): Expansion and ejection stages * 13N, 18F: Early gamma-ray emission (511 keV plus continuum) * 7Be, 22Na, 26Al: Gamma-ray lines
Isotope Lifetime Disintegration Nova type 17F 93 sec β+-decay CO & ONe 14O 102 sec β+-decay CO & ONe 15O 176 sec β+-decay CO & ONe 13N 862 sec β+-decay CO & ONe 18F 158 min β+-decay CO & ONe 7Be 77 day e—capture CO
22Na 3.75 yr β+-decay ONe 26Al 1.0 Myr β+-decay ONe
γ-Ray Emission from Classical Novae
J. José Classical Novae Nuclear Symphony || Observational Constraints || Multidimensional Models
* γ-ray signature: 18F decay (T1/2 ~ 110 min) provides a source of gamma-ray emission at 511 keV and below (related to electron-positron annihilation). But! Uncertainties in the rates translate into a factor ∼ 5 - 10 uncertainty in the expected fluxes! 1.15 Mo CO
D= 1 kpc Gómez-Gomar, Hernanz, JJ, & Isern (1998), MNRAS
J. José Classical Novae Nuclear Symphony || Observational Constraints || Multidimensional Models
18F
MareNostrum II (BSC, 2006), 94.21 Tflops/s, 10,240 processors MareNostrum III (BSC, Jan. 2013), >1 Petaflop/s, 48,000 processors [6,000 Intel SandyBridge chips (2,6 GHz), each with 8 cores]
J. José
Zmean ~ 0.2 – 0.3
3D Models of Mixing
Classical Novae Nuclear Symphony || Observational Constraints || Multidimensional Models
Classical Novae at the Crossroads of Astrophysics, Nuclear Physics and Cosmochemistry XXVII Texas Symp. on Relativistic Astrophysics
Dallas (Texas), Dec. 8 – 13, 2013
Thank you for your attention!