Stable Isotopes and Nova Explosions Jordi Jos Dept

Stable Isotopes and Nova Explosions Jordi José Dept. Física i Enginyeria Nuclear, Universitat Politècnica de Catalunya & Institut d’Estudis Espacials de Catalunya, Barcelona

Classical Nova Outbursts Discovered more than 2. 000 years ago. . . Observed in all wavelengths (but never detected so far in γ-rays) Pioneering TNR models: Starrfield et al. 1972; Prialnik, Shara, & Shaviv 1978 CNe: Moderate rise times (<1 – 2 days): 8 – 18 magnitude increase in brigthness LPeak ~ 104 Lo Recurrence time: ~ 104 – 105 yr Frequency: 30 ± 10 yr-1 E 1045 erg Mass ejected: 10 -4 – 10 -5 Mo (102 – 103 km s-1)

Nova Nucleosynthesis ~ 100 relevant isotopes (A<40) & a (few) hundred nuclear reactions (Tpeak ~ 100 – 400 MK) “Novae as unique stellar explosions for which the nuclear physics input is/will be soon primarily based on experimental information” (José, Hernanz & Iliadis 2006) In few years, uncertainties in nova nucleosynthesis will be exclusively associated to modeling!

Endpoint of nova nucleosynthesis? 1. 35 Mo ONe Tpeak 30 P(p, )31 S José, Coc & Hernanz (2001) Main nuclear path close to the valley of stability, and driven by (p, γ), (p, α) and β+ reactions Negligible contribution from any (n, γ) or (α, γ) reaction: No 15 O(α, γ), please! Endpoint of (classical) nova nucleosynthesis ~ Ca

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. 0017 0. 28 (JH 98)

Too early to enjoy Coffee grains, so let’s talk about Si. C grains. . . Si. C grains are the most extensively studied ones AGBs C stars? AGBs Supernovae ~93% of all Si. C grains (mainstream Population) formed in the winds of Z☼ AGB stars (Gallino et al. 1993; Lugaro et al. 2003; Ott & Begemann 1990).

~7 350 post-processing simulations to identify the most influencial nuclear uncertainties (rates) >44 000 post-processing simulations for XRB nucleosynthesis (14 CPU months) [Parikh, José, Moreno, & Iliadis 2008]

Angulo et al. (1999), NPA

* Nuclear uncertainties affecting 30 P(p, )31 S influence Si yields (relevant for the identification of presolar nova candidate grains) and the nuclear activity beyond S: - for high 30 P(p, g) rates (100 x nominal rate): 30 Si is reduced by a factor of 30 - for low 30 P(p, g) rates (0. 01 x nominal rate): 30 Si is increased by a factor of 5, whereas elements above Si decrease by a factor of 10. Need for new nuclear physics experiments 30 P(p, )31 S: D. G. Jenkins, A. Meadowcroft, C. J. Lister, M. P. Carpenter, P. Chowdhury, N. J. Hammond, R. V. F. Janssens, T. L. Khoo, T. Lauritsen, D. Seweryniak, T. Davinson, P. J. Woods, A. Jokinen, H. Penttila, G. Martínez-Pinedo, J. José, (PRC, 2006): 12 C(20 Ne, n)31 S , Gammasphere

Reduction of the few nuclear uncertainties that remain in the “post-NACRE Era”: 18 F(p, )15 O, 25 Al(p, )26 Si, & 30 P(p, )31 S But room for some reactions involving stable isotopes such as: 29 Si(p, )30 P, for instance