Jordi José Dept. Física i Enginyeria Nuclear, Universitat Politècnica de Catalunya & Institut d Estudis Espacials de Catalunya, Barcelona

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1 Nucleosynthesis in Classical Novae Jordi José Dept. Física i Enginyeria Nuclear, Universitat Politècnica de Catalunya & Institut d Estudis Espacials de Catalunya, Barcelona Stellar Explosions: Classical Novae, SNIa,, & XRBs Close Binary System WD/NS Star MS Companion Mass transfer: Roche lobe overflow (L 1 ) Type Ia Ia (or (or thermonuclear) Supernovae [SN Ia] Ia] Classical Nova Outbursts [CN] WD X-Ray Bursts [XRBs]: NS 1

2 Classical Nova Outbursts Discovered more than years ago... Observed in in all allwavelengths (but never detected so so far farin in γ-rays) Pioneering TNR models: Starrfield et et al. al. 1972; Prialnik, Shara, & Shaviv 1978 CNe: Moderate rise times (<1 2 days): magnitude increase in in brigthness L o o L Peak Peak ~ Recurrence time: ~ yr yr Frequency: ± yr yr -1-1 E erg Mass ejected: M o o ( km s -1-1 )) Nova Cygni 1992 Nova Nucleosynthesis * Classical Novae: ~ 100 relevant isotopes (A<40) & a (few) hundred nuclear reactions (T (T peak ~ peak MK) Novae as as unique stellar explosions for for which the thenuclear physics input is/will be be soon primarily based on on experimental information (José, Hernanz & Iliadis 2006) 2

3 The TheNuclear NuclearPhysics Physicsof ofclassical ClassicalNovae Novae 1.35 Mo ONe Tpeak Main Mainnuclear nuclearpath pathclose closetotothe thevalley valleyof ofstability, stability,and anddriven drivenby by(p,γ), (p,γ), ++reactions (p,α) and β (p,α) and β reactions Negligible Negligiblecontribution contributionfrom fromany any(n,γ) (n,γ)or or(α,γ) (α,γ)reaction: reaction:no No O(α,γ), O(α,γ),please! please! Relevant Relevant nucleosynthesis nucleosynthesis involves involves ~~ isotopes isotopes (Z (Z ~~ 20) 20) && aa (few) (few) hundred nuclear reactions (based primarily on experimental hundred nuclear reactions (based primarily on experimentalinformation) information) Endpoint Endpointof of(classical) (classical)nova novanucleosynthesis nucleosynthesis~~ca Ca Main Mainnuclear nuclearuncertainties: uncertainties:[[18f(p,α) F(p,α)O, O, 25Al(p,γ) Al(p,γ)Si, Si, 30P(p,γ) P(p,γ)31S] S] 3

4 Triggering reaction: C(p,γ) N As As T increases: τ (p,γ) (p,γ) [[ N] N] < τ (β+) (β+) [[ N] N] 13 N(β + ) 13 C(p,γ) 14 N (cold CNO) N(p,γ) O (hot CNO) N(p,γ) O O(p,γ) F Critical role of of convection: carrying the the short-lived, β + -unstable nuclei 14, 14, O, O, F (( N) N) to to the the outer, cooler layers of of the the envelope (escaping deadly p-capture reactions) Sudden release of of energy from these short-lived species powers the the expansion and ejection stages [Starrfield et et al.1972]: N, N, O (( C) C) Without convection, there s no nova outburst! Hydrodynamic nova models Mass ejection (~ 2 x 10-5 M o ) Since T peak ~ (2-3) x 10 8 K Nuclear processed material Which is the role of nova outbursts in the Galactic chemical puzzle? Galactic nova rate: ~ 30 events.yr -1 Galaxy s lifetime: ~ yr Mean ejected mass per outburst: ~ 2 x 10-5 M o ~ 6 x 10 6 M o (~ 1/3000 of the Galactic disk s gas & dust component) Novae scarcely contribute to tothe thegalactic abundances, but they can be be likely sites for forthe thesynthesis of ofindividual nuclei with overproduction factors, f f = X i i // X i, i, solar solar >

5 José & Hernanz (1998), ApJ 1. Mo CO 1. Mo ONe Classical Classical novae novae are are likely likely sites sites for for the the synthesis of a significant fraction synthesis of a significant fraction of of the Galactic C, N & O, and the Galactic C, N & O, and contribute contribute to to the the Galactic Galactic content content of of 7 7 Li, or Al other species like other species like Li, or Al 1.35 Mo ONe Nova Nova Radioactivities: Radioactivities: 18F, F, 22Na, Na, Al Al Isotope Lifetime Disintegration Nova type 17F 93 sec CO & ONe 14O 102 sec CO & ONe CO & ONe O 176 sec 13N 862 sec CO & ONe 18F 8 min CO & ONe 7Be 77 day e--capture CO 22Na 3.75 yr ONe Al 1.0 Myr ONe Main radioactive species synthesized during nova outbursts * 14, O, 17F (13N): Expansion and ejection stages * 13N, 18F: Early gamma-ray emission (511 kev plus continuum) * 7Be, 22Na, Al: Gamma-ray lines 5

6 22 22 Na * Clayton & Hoyle (1974): potential role of 22 Na for diagnosis of nova outbursts τ ~ 3.75 yr 22 Na 22 Ne MeV * Iyudin et al. (1995): upper limit of 3.7 x 10-8 M o of 22 Na ejected by any novae in the Galactic disk Constraints on pre-existing theoretical models! Peak fluxes for forthe the1275 kev γ-ray line (( Na Nadecay) might be be detectable by by near future gamma-ray satellites (i.e. INTEGRAL: d<0.5 kpc) 1. M o ONe 22 Na cumulative emission D= 1 kpc Gómez-Gomar, Hernanz, José, & Isern (1998), MNRAS Jean, Hernanz, Gómez-Gomar, & José (2000), MNRAS 6

7 18 18 F Main contributor to the prompt gamma-ray emission Nuclear uncertainties: 18 F(p,γ) 19 Ne, 18 F(p,α) O, 17 O(p,γ) 18 F, 17 O(p,α) 14 N (Hernanz, José, Coc, Gómez-Gomar, Isern 1999; Coc, Hernanz, José, Thibaud 2000) Recent improvements: de Séréville et al. (2003), Bardayan et al. (2003), Kozub et al. (2004), Chae et al. (2006): 18 F(p,α) O Fox et al. (2004, 2005), Chafa et al. (2005, 2007): 17 O(p,α), 17 O(p,γ) 18 F decay (τ ~ 8 min) provides a source of gamma-ray emission at 511 kev and below (related to electron-positron annihilation). But! Uncertainty in the predicted fluxes (nuclear physics origin) Constraining theoretical predictions of of Classical Nova Models In In situ observations (highly risky...) 7

8 Models vs. vs. Observations for forsome Classical Nova Systems H He C N O Ne Na-Fe Z V693 CrA 1981 Vanlandingham et al. (1997) ONe3 (JH98) Andreä et al. (1994) ONe4 (JH98) Williams et al. (1985) ONe5 (JH98) V1370 Aql 1982 Andreä et al. (1994) ONe7 (JH98) Snijders et al. (1987) ONe7 (JH98) PW Vul 1984 Andreä et al. (1994) CO4 (JH98) QU Vul 1984 Austin et al. (1996) ONe1 (JH98) C stars? AGBs AGBs Supernovae Presolar Grains: Gifts from Heaven A rare variety of ofsic grains (<1%), together with a couple of of graphite grains, have been atributed to to classical nova outbursts (Amari et et al. al. 2001, Amari 2002). 8

9 Five Five SiC SiC and and two two graphite graphite grains, grains, whose whose isotopic isotopic ratios ratios point point toward toward aa nova origin: low C/ C and N/ N ratios, high Si/ Si, nova origin: low C/ C and N/ N ratios, high Si/ Si, and and close-to-solar Si/ Si. Al/ Al and Ne/ Ne ratios have been close-to-solar Si/ Si. Al/ Al and Ne/ Ne ratios have been determined determined for for some some of of these these grains, grains, with with values values compatible compatible with with nova model predictions. ( nova model predictions. ( But... But... Can Cannova novaexplosions explosionslead leadto toti Tisynthesis? synthesis? Yes, Yes,ififwe wemanage manageto toproduce produceslightly slightlymore moreviolent violentoutbursts: outbursts: **Explosions Explosionsin inlower lowerll(colder) (colder)wds WDsor orin inlow-accretion low-accretionrate rate episodes: José & Hernanz 2007, Meteor. & Planet. Sci., in episodes: José & Hernanz 2007, Meteor. & Planet. Sci., inpress press **Primordial novae: José, García-Berro, Hernanz, & Gil-Pons Primordial novae: José, García-Berro, Hernanz, & Gil-Pons 2007, 2007,ApJL, ApJL,in inpress press A new type of explosion, halfway between a Nova and a Supernova! primordial 9

10 Primordial PrimordialNovae: Novae:the thefirst FirstNova NovaExplosions Explosions Primordial PrimordialNovae Novae==Nova-like, Nova-like,stellar stellarexplosions explosionson onwhite whitedwarfs dwarfs evolved in a cataclysmic primordial binary (Z 0). evolved in a cataclysmic primordial binary (Zzams zams~~ 0). Solar [Fe/H] = -5.3 José, José,García-Berro, García-Berro,Hernanz, Hernanz,&&Gil-Pons Gil-Pons(2007) (2007) 10

11 MargaritaHernanz, Hernanz,Jordi JordiGómez-Gomar Gómez-Gomar Margarita (IEEC, Barcelona) (IEEC, Barcelona) EnriqueGarcía-Berro, García-Berro,Pilar PilarGil-Pons Gil-Pons Enrique (UPC, Barcelona) (UPC, Barcelona) AlainCoc Coc(CSNSM, (CSNSM,Orsay) Orsay) Alain ChristianIliadis Iliadis(UNC, (UNC,Chapel ChapelHill) Hill) Christian SachikoAmari, Amari,Ernst ErnstZinner, Zinner,Katharina Katharina Sachiko Lodders (WUSL, St. Louis) Lodders (WUSL, St. Louis) SteveShore Shore(Univ. (Univ.Pisa) Pisa) Steve Jordi José Nucleosynthesis in Classical Novae XIX Rencontres de Blois Matter and Energy in the Universe: from Nucleosynthesis to Cosmology, Château Royal de Blois, France, May 20-25,