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We test the effect of proton-capture reaction rate uncertainties on the abundances of the Ne, Na, Mg and Al isotopes processed by the NeNa and MgAl chains during hot bottom burning (HBB) in asymptotic giant branch (AGB) stars of…

Astrophysics · Physics 2009-11-13 R. G. Izzard , M. Lugaro , A. I. Karakas , C. Iliadis , M. van Raai

We study the effect of uncertainties in the proton-capture reaction rates of the NeNa and MgAl chains on nucleosynthesis due to the operation of hot bottom burning (HBB) in intermediate-mass asymptotic giant branch (AGB) stars. HBB…

Astrophysics · Physics 2008-11-26 Robert Izzard , Maria Lugaro , Christian Iliadis , Amanda Karakas

We investigate the effects of thermonuclear reaction rate variations on 26Al production in massive stars. The dominant production sites in such events were recently investigated by using stellar model calculations: explosive neon-carbon…

Solar and Stellar Astrophysics · Physics 2015-05-27 Christian Iliadis , Art Champagne , Alessandro Chieffi , Marco Limongi

The cosmic production of the short-lived radioactive nuclide 26Al is crucial for our understanding of the evolution of stars and galaxies. However, simulations of the stellar sites producing 26Al are still weakened by significant nuclear…

Calculations that demonstrate the influence of three key nuclear reaction rates on the evolution of Asymptotic Giant Branch stars have been carried out. We study the case of a star with an initial mass of 2Msun and a metallicity of Z=0.01,…

Astrophysics · Physics 2009-11-13 F. Herwig , Sam M. Austin , John C. Lattanzio

The 16O(p,gamma)17F reaction rate is revisited with special emphasis on the stellar temperature range of T=60-100 MK important for hot bottom burning in asymptotic giant branch (AGB) stars. We evaluate existing cross section data that were…

Astrophysics · Physics 2009-06-23 C. Iliadis , C. Angulo , P. Descouvemont , M. Lugaro , P. Mohr

Among presolar materials recovered in meteorites, abundant SiC and Al$_{2}$O$_{3}$ grains of AGB origins were found. They showed records of C, N, O, $^{26}$Al and s-element isotopic ratios that proved invaluable in constraining the…

Solar and Stellar Astrophysics · Physics 2015-06-18 M. Busso , O. Trippella , E. Maiorca , S. Palmerini

We report the first tungsten isotopic measurements in stardust silicon carbide (SiC) grains recovered from the Murchison carbonaceous chondrite. The isotopes 182W, 183W, 184W, 186W and 179Hf, 180Hf were measured on both an aggregate (KJB…

Solar and Stellar Astrophysics · Physics 2015-05-30 J. N. Ávila , M. Lugaro , T. R. Ireland , F. Gyngard , E. Zinner , S. Cristallo , P. Holden , J. Buntain , S. Amari , A. Karakas

Presolar grains are stardust particles that condensed in the ejecta or in the outflows of dying stars and can today be extracted from meteorites. They recorded the nucleosynthetic fingerprint of their parent stars and thus serve as valuable…

Solar and Stellar Astrophysics · Physics 2024-12-02 Hung Kwan Fok , Marco Pignatari , Benoît Côté , Reto Trappitsch

Stardust grains that originated in ancient stars and supernovae are recovered from meteorites and carry the detailed composition of their astronomical sites of origin. We present evidence that the majority of large ($\mu$m-sized) meteoritic…

Over the last three years, the rates of all the main nuclear reactions involving the destruction and production of $^{26}$Al in stars ($^{26}$Al(n, p)$^{26}$Mg, $^{26}$Al(n, $\alpha$)$^{23}$Na, $^{26}$Al(p, $\gamma$)$^{27}$Si and…

Solar and Stellar Astrophysics · Physics 2026-01-12 Umberto Battino , Lorenzo Roberti , Thomas V. Lawson , Alison M. Laird , Lewis Todd

We present detailed models of low and intermediate-mass asymptotic giant branch (AGB) stars with and without the 18F(a,p)21Ne reaction included in the nuclear network, where the rate for this reaction has been recently experimentally…

Astrophysics · Physics 2009-11-13 Amanda Karakas , Hye Young Lee , Maria Lugaro , Joachim Goerres , Michael Wiescher

We present nucleosynthesis calculations and the resulting 19F stellar yields for a large set of models with different masses and metallicity. We find that the production of fluorine depends on the temperature of the convective pulses, the…

We present new rates for the 22Ne(alpha, n)25Mg and 22Ne(alpha,gamma)26Mg reactions, with uncertainties that have been considerably reduced compared to previous estimates, and we study how these new rates affect the production of the heavy…

Astrophysics · Physics 2011-07-19 A. Karakas , M. Lugaro , M. Wiescher , J. Goerres , C. Ugalde

Stars on the asymptotic giant branch (AGB) produce dust in their circumstellar shells. The nature of the dust-forming environment is influenced by the evolution of the stars, in terms of both chemistry and density, leading to an evolution…

Astrophysics · Physics 2009-11-13 Angela Speck , Grant Thompson , Anne Hofmeister

Aluminium-26 is a radioactive isotope which can be synthesized within asymptotic giant branch (AGB) stars, primarily through hot bottom burning. Studies exploring $^{26}$Al production within AGB stars typically focus on single-stars;…

Solar and Stellar Astrophysics · Physics 2023-10-26 Zara Osborn , Amanda I. Karakas , Alex J. Kemp , Robert G. Izzard

Asymptotic giant branch (AGB) stars with low initial mass (1 - 3 Msun) are responsible for the production of neutron-capture elements through the main s-process (main slow neutron capture process). The major neutron source is 13C(alpha,…

Solar and Stellar Astrophysics · Physics 2022-10-26 S. Bisterzo , R. Gallino , F. Kaeppeler , M. Wiescher , C. Travaglio

We present dust yields for asymptotic giant branch (AGB) and super--asymptotic giant branch (SAGB) stars of solar metallicity. Stars with initial mass $1.5~M_{\odot} \leq M_{\rm ini} \leq 3~M_{\odot}$ reach the carbon star stage during the…

Solar and Stellar Astrophysics · Physics 2017-07-26 F. Dell'Agli , D. A. García-Hernádez , R. Schneider , P. Ventura , F. La Franca , R. Valiante , E. Marini , M. Di Criscienzo

We investigate both the systematic and statistical uncertainties associated with theoretical nuclear reaction rates of relevance during the i-process and explore their impact on the i-process elemental production, and subsequently on the…

Solar and Stellar Astrophysics · Physics 2023-10-16 S. Martinet , A. Choplin , S. Goriely , L. Siess

Low-resolution infrared spectroscopy from JWST confirms the presence of SiC and likely metallic iron dust around asymptotic giant branch (AGB) stars in the Sextans A dwarf galaxy, which has a metallicity ~1%-7% Z_sun. While metal-poor…

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