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Moazen, B. H.; Bardayan, D. W.; Blackmon, J. C.; Chae, K. Y.; Chipps, K. A.; Domizioli, C. P.; Fitzgerald, R.; Greife, U.; Hix, W. R.; Jones, K. L.; Kozub, R. L.; Lingerfelt, Eric J.; Livesay, R. J.; Nesaraja, C. D.; Pain, S. D.; Roberts, Luke F.; Shriner, J. F.; Smith, M. S.; Thomas, J. S.

doi:10.1103/physrevc.75.065801

Cited by 29 publications

(17 citation statements)

References 21 publications

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“…They found that with their new 17 O+p rates, the final abundances of 17 O and 18 F were reduced by factors of 2-3 relative to those from Fox et al, and by factors of 1.4 and 8, respectively, relative to those using the NACRE rates. Moazen et al172 tested the impact of similar rates to those of Chafa et al (in agreement to better that 5% over nova temperatures) using a multi-zone post-processing approach160 (where final abundances are determined by neglecting any mixing and simply summing the contributions of each zone weighted by the total mass of the zone). For a similar mass white dwarf(1.15 M ) to that used in the hydrodynamic tests mentioned above, they find reductions by a factor of 10 in the abundance of 18 F relative to the abundance of 18 F determined using the NACRE17 O+p rates.…”

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confidence: 88%

Classical novae and type I X-ray bursts: Challenges for the 21st century

2014

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Classical nova explosions and type I X-ray bursts are the most frequent types of thermonuclear stellar explosions in the Galaxy. Both phenomena arise from thermonuclear ignition in the envelopes of accreting compact objects in close binary star systems. Detailed observations of these events have stimulated numerous studies in theoretical astrophysics and experimental nuclear physics. We discuss observational features of these phenomena and theoretical efforts to better understand the energy production and nucleosynthesis in these explosions. We also examine and summarize studies directed at identifying nuclear physics quantities with uncertainties that significantly affect model predictions.

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confidence: 88%

Classical novae and type I X-ray bursts: Challenges for the 21st century

2014

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“…Another reaction that turned out to be of surprisingly strong influence is the 17 O(p, α) 14 N reaction. We tested this by employing either the recent measurements by Moazen et al (2007), which for T > 4×10 8 K is very similar to the NACRE recommendation, or the one given by Caughlan & Fowler (1988). A detailed discussion on the reaction rates can be found in § 4.2.…”

Section: Garstecmentioning

confidence: 99%

On Using the Color-Magnitude Diagram Morphology of M67 to Test Solar Abundances

Magic

Serenelli

Weiß

et al. 2010

ApJ

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The open cluster M67 has solar metallicity and an age of about 4 Gyr. The turn-off mass is close to the minimum mass for which solar metallicity stars develop a convective core during main sequence evolution as a result of the development of hydrogen burning through the CNO-cycle. The morphology of the color-magnitude-diagram (CMD) of M67 around the turn-off shows a clear hook-like feature, direct sign that stars close to the turn-off have convective cores. VandenBerg et al. investigated the possibility of using the morphology of the M67 turn-off to put constraints on the solar metallicity, particularly CNO elements, for which solar abundances have been revised downwards by more than 30% over the last few years. Here, we extend their work filling in the gaps in their analysis. To this aim, we compute isochrones appropriate for M67 using new (low metallicity) and old (high metallicity) solar abundances and study whether the characteristic turn-off in the CMD of M67 can be reproduced or not. We also study the importance of other constitutive physics on determining the presence of such a hook, particularly element diffusion, overshooting and nuclear reaction rates. We find that using the new solar abundance determinations, with low CNO abundances, makes it more difficult to reproduce the characteristic CMD of M67. This result is in agreement with results by VandenBerg et al. However, changes in the constitutive physics of the models, particularly overshooting, can influence and alter this result to the extent that isochrones constructed with models using low CNO solar abundances can also reproduce the turn-off morphology in M67. We conclude that only if all factors affecting the turn-off morphology are completely under control (and this is not the case), M67 could be used to put constraints on solar abundances.

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“…17 O(p,α) 14 N. Several experiments (Chafa et al 2007;Newton et al 2010;Moazen et al 2007) have determined the magnitude of most of the several resonances that influence the rate of this reaction. As for the 17 O(p,γ) 18 F, the E cm = 65 keV resonance, directly at the astrophysically relevant energy, makes the reaction rate determination difficult, and the uncertainty is correspondingly large.…”

Section: Reaction Rate Uncertaintiesmentioning

confidence: 99%

Effects of nuclear cross sections on¹⁹F nucleosynthesis at low metallicities

Cristallo

Leva

Imbriani

et al. 2014

A&A

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Context. The origin of fluorine is a longstanding problem in nuclear astrophysics. It is widely recognized that asymptotic giant branch (AGB) stars are among the most important contributors to the Galactic fluorine production. Aims. In general, extant nucleosynthesis models overestimate the fluorine production by AGB stars with respect to observations. Although those differences are rather small at solar metallicity, low metallicity AGB stellar models predict fluorine surface abundances up to one order of magnitude larger than the observed ones. Methods. As part of a project devoted to reducing the uncertainties in the nuclear physics that affect the nucleosynthesis in AGB stellar models, we review the relevant nuclear reaction rates involved in the fluorine production or destruction. We perform this analysis on a model with initial mass M = 2 M and Z = 0.001. Results. We found that the major uncertainties are due to the 13 C(α,n) 16 O, the 19 F(α,p) 22 Ne, and the 14 N(p,γ) 15 O reactions. A change in the corresponding reaction rates within the present experimental uncertainties implies surface 19 F variations at the AGB tip lower than 10%, thus much smaller than observational uncertainties. For some α capture reactions, however, cross sections at astrophysically relevant energies are determined on the basis of nuclear models, in which some low-energy resonance parameters are very poorly known. Thus, larger variations in the rates of those processes cannot be excluded. That being so, we explore the effects of the variation in some α capture rates well beyond the current published uncertainties. The largest 19 F variations are obtained by varying the 15 N(α,γ) 19 F and the 19 F(α,p) 22 Ne reactions. Conclusions. The currently estimated uncertainties of the nuclear reaction rates involved in the production and destruction of fluorine produce minor 19 F variations in the ejecta of AGB stars. Analysis of some α capture processes that assume a wider uncertainty range determines 19 F abundances in better agreement with recent spectroscopic fluorine measurements at low metallicity. In the framework of this scenario, the 15 N(α,γ) 19 F and the 19 F(α,p) 22 Ne reactions show the strongest effects on fluorine nucleosynthesis. The presence of poorly known low-energy resonances make such a scenario possible, even if it is unlikely. We plan to measure these resonances directly.

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Measurement of the 183 keV resonance inO17(p,α)

Cited by 29 publications

References 21 publications

Classical novae and type I X-ray bursts: Challenges for the 21st century

Classical novae and type I X-ray bursts: Challenges for the 21st century

On Using the Color-Magnitude Diagram Morphology of M67 to Test Solar Abundances

Effects of nuclear cross sections on¹⁹F nucleosynthesis at low metallicities

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Measurement of the 183 keV resonance inO17(p,α)

Cited by 29 publications

References 21 publications

Classical novae and type I X-ray bursts: Challenges for the 21st century

Classical novae and type I X-ray bursts: Challenges for the 21st century

On Using the Color-Magnitude Diagram Morphology of M67 to Test Solar Abundances

Effects of nuclear cross sections on19F nucleosynthesis at low metallicities

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Effects of nuclear cross sections on¹⁹F nucleosynthesis at low metallicities