1 / 22

Improving Predictions of Nova Models through Nuclear Physics Measurements

This article discusses the improvement of predictions in nova models through nuclear physics measurements. It explores the use of reaction networks and experiments with magnetic spectrographs to provide useful information for indirect calculations of thermonuclear reaction rates. The article also discusses the impact of these measurements on estimating rates for model calculations.

jimmyh
Download Presentation

Improving Predictions of Nova Models through Nuclear Physics Measurements

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Improvingpredictionsfrom nova modelsthrough nuclear physicsmeasurements Anuj Parikh Universitat Politècnica de Catalunya Institut d'Estudis Espacials de Catalunya Barcelona, Spain

  2. Improvingpredictionsfrom nova modelsthrough nuclear physicsmeasurements Anuj Parikh Universitat Politècnica de Catalunya Institut d'Estudis Espacials de Catalunya Barcelona, Spain Nova modeling: see plenary talk by J. José 9:30-10, Wednesday!

  3. OBSERVATIONS NOVA CYGNI 1992 history IUE (1978 - 1996) ≈ 30 000 AU ≈ 0.002" Nova Cygni 1992 (d ~ 10 000 ly) ESA / IUE HST (1994)

  4. MODELS → for nucleosynthesis − 1D hydrodynamic → reaction networks: ≈ 100 species, H − Ca 13C, 15N, 17O 7Li, 26Al (??) solar José and Hernanz (2007) José, Casanova, Moreno, García-Berro, AP, and Iliadis (2010) Most of the thermonuclear reaction rates involved are constrained by experiments NACRE 1999, Iliadis+ 2001, Iliadis+ 2010

  5. NUCLEAR PHYSICS José and Hernanz (2007) José et al. (2010) José and Iliadis (2011) Most of the thermonuclear reaction rates involved are constrained by experiments

  6. NUCLEAR PHYSICS: recent studies with the Munich Q3D magnetic spectrograph 30P(p,γ)31S →31P(3He,t)31S →32S(d,t)31S 33S(p,γ)34Cl →34S(3He,t)34Cl →33S(3He,d)34Cl 26Al(p,γ)27Si →28Si(3He,α)27Si 18F(p,α)15O →19F(3He,t)19Ne → 20Ne(d,t)19Ne José, Casanova, Moreno, García-Berro, AP, and Iliadis (2010)

  7. Experiments with magnetic spectrographs can provide nuclear physics information useful for INDIRECT calculations of thermonuclear reaction rates • → Ex, Jπ, C2S, Γx/Γtot... • Such experiments are useful • when σ are too low for direct studies • when suitable beams/targets are not available for direct studies • when level densities are not "too high" • to identify key resonances and guide future direct studies • to help estimate rates "in the meantime" for model calculations • to keep nuclear physicists occupied MLL Q3D IPNO Split-Pole (Yale Split-Pole)

  8. Experiments with magnetic spectrographs can provide nuclear physics information useful for INDIRECT calculations of thermonuclear reaction rates → Ex, Jπ, C2S, Γx/Γtot... IPNO Enge Split-Pole dΩnom ~ 1.7 msr ΔE/E ~ 5 x 10-4 Δρ ~ 21 cm I3He ~ 50 nA VTmax ~ 14 MV MLL Q3D dΩnom ~ 14 msr ΔE/E ~ 2 x 10-4 Δρ ~ 6 cm I3He ~ 500 nA VTmax ~ 14 MV +MAGNEX (INFN/LNS-Catania), Q3D (CIAE-Beijing), Grand Raiden (RCNP-Osaka)...

  9. Q3D MAGNETIC SPECTROGRAPH Maier-Leibnitz-Laboratorium (Garching, Germany)

  10. Q3D MAGNETIC SPECTROGRAPH Maier-Leibnitz-Laboratorium (Garching, Germany)

  11. Q3D MAGNETIC SPECTROGRAPH Maier-Leibnitz-Laboratorium (Garching, Germany) 31P(3He,t)31S 3H 3H 3H 3H 31P, 31S 3He

  12. 30P(p,γ)31S : STATUS DIRECT :No high quality, high I beams of 30P available (>106 pps of 30P) INDIRECT: some Ex, Jπ ; no Γx(for Tnova) IMPACT: varying a theoretical rate by a factor of 10 1D hydro nova model José et al. 2001 30P+p Q = 6133 keV 31S 30P (1+, t1/2 = 2.5 min)

  13. 30P(p,γ)31S via 31P(3He,t)31S E3He = 20 MeV, 1.5° Yale Split-Pole ΔE = 25 keV 5 d @ 50 nA Wrede + (2007, 2009) E3He = 25 MeV, 10° MLL Q3D 12 h @ 650 nA ΔE = 10 keV AP+ (2011) counts 30P+p Q = 6133 keV 31S 30P (1+, t1/2 = 2.5 min)

  14. 30P(p,γ)31S via 31P(3He,t)31S E3He = 20 MeV 1.5° Yale Split-Pole ΔE = 25 keV 5 d @ 50 nA Wrede et al. 2007 dσ/dΩ (μb/sr) dσ/dΩ (μb/sr) 1/2+ ϴCM (deg) ϴCM (deg) E3He = 25 MeV, 10° MLL Q3D 12 h @ 650 nA ΔE = 10 keV AP+ (2011) counts 30P+p Q = 6133 keV 31S 30P (1+, t1/2 = 2.5 min)

  15. 30P(p,γ)31S via 31P(3He,t)31S Contributors to remaining uncertainty: unknown Γp existence of doublet at 6.40 MeV not seen in recent γ-ray study (Doherty+ 2012, fusion-evaporation) AP++ (2011) experimental rate varied within uncertainties 1D hydro nova model

  16. 30P(p,γ)31S via 32S(d,t)31S 30P(p,γ)31S via 31P(3He,t)31S Ed= 24 MeV MLL Q3D ΔE = 8 keV Irvine, Chen, AP++ (submitted) E3He = 25 MeV, 10° MLL Q3D ΔE = 10 keV AP++ (2011) 25° 54°

  17. 18F(p,α)15O: STATUS T of interest for novae DIRECT: Beer+ (2011) TRIUMF 5x106 pps 2 counts in 5 days • Interference between broad 3/2+ at 665 keV with "3/2+(?)" states at "8" and "38" keV • factor of ≈5 variation in the rate at 0.2 GK affects 18F production in novae by a factor of ≈2 PROHIBITIVE. look for help from indirect methods... → only tentative Jπ for ER < 665 keV

  18. 18F(p,α)15O via 19F(3He,t)19Ne Laird, AP++ PRL (2013) 19F(3He,t)19Ne, 25 MeV MLL Q3D, ΔE = 15 keV Three states observed around 6.4 MeV all with different experimental angular distributions Previously, two states (3/2+) states had been assumed R-matrix fit → nova model:

  19. 26Al(p,γ)27Si: STATUS ≈100 keV lower measured DIRECT: E of interest for novae Ruiz, AP++ (2006) TRIUMF 3x109 pps 150 cts in 10 days (lowest E measured) • 2 lower energy resonances, ≈ weeks to months needed with a (non-existent) 26Al target of 1017 /cm2 + 100 μA proton beam • rate uncertainty at relevant T > factor of 10...can affect 26Al produced in novae and Wolf-Rayet stars by a factor of ≈2 (Iliadis++ 2002, 2010, 2011) PROHIBITIVE. look for help from indirect methods...

  20. 26Al(p,γ)27Si via 28Si(3He,α)27Si studied previously (Schmalbrock+ 1986, Wang+ 1989) , no Jπ assigned E = 25 MeV 15° MLL Q3D AP++ (2011) ΔE ~ 12 keV Jπ determined still need Γp

  21. 26Al(p,γ)27Si via 26Al(3He,d)27Si to obtain proton-transfer C2S → Γp PREVIOUS ATTEMPT Create a 26Al target using implantation. Approved (high priority) at TRIUMF-ISAC I26Al ≈ 3 x 1010 pps → 26Al(3He,d)27Si AND → 26Al(3He,t)26Si*(p)25Al for Γp / Γfor 25Al(p,γ)26Si Vogelaar+ (1996) Princeton Q3D 20 MeV, 5° ΔE = 12 keV 26Al TARGET: 1016 atoms/cm2 (evaporation) 6% 26Al comparable to all previous 26Al targets (Buc84, Koe97, Ing02 ... )

  22. d = 8.6 ly DA-B = 8 − 30 AU Classical nova explosions Compact object: white dwarf (CO / ONe) Lmax: ~ 104 – 105 Lsol tlightcurve: ~ days – months Torbital: ~ 1 – 16 h trec: ~ 104 – 105 yr Tpeak: ~ 0.1 – 0.4 GK ρpeak: ~ 103– 104 g / cm3 envelope: ~ 100 km #Galaxy: ~ 30 / yr Ejecta: ~ 10-4 – 10-5 Msol / nova Sirius A MS star Sirius B white dwarf HST ≈ 30 000 AU ≈ 0.002" nucleosynthesis: H – Ca Most of the thermonuclear reaction rates involved are constrained by experiments Nova Cygni 1992 (d ~ 10 000 ly) HST (1994)

More Related