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Chromium Nucleosynthesis and Silicon-Carbon Shell Mergers in Massive Stars (2020)
Journal Article
Côté, B., Jones, S., Herwig, F., & Pignatari, M. (2020). Chromium Nucleosynthesis and Silicon-Carbon Shell Mergers in Massive Stars. The Astrophysical journal, 892(1), https://doi.org/10.3847/1538-4357/ab77ac

We analyze the production of the element Cr in galactic chemical evolution (GCE) models using the NuGrid nucleosynthesis yields set. We show that the unusually large [Cr/Fe] abundance at [Fe/H] ≈ 0 reported by previous studies using those yields and...

The Nucleosynthetic Yields of Core-collapse Supernovae: Prospects for the Next Generation of Gamma-Ray Astronomy (2020)
Journal Article
Andrews, S., Fryer, C., Even, W., Jones, S., & Pignatari, M. (2020). The Nucleosynthetic Yields of Core-collapse Supernovae: Prospects for the Next Generation of Gamma-Ray Astronomy. The Astrophysical journal, 890(1), https://doi.org/10.3847/1538-4357/ab64f8

Though the neutrino-driven convection model for the core-collapse explosion mechanism has received strong support in recent years, there are still many uncertainties in the explosion parameters—such as explosion energy, remnant mass, and end-of-life...

Evaluation of the $^{13}$N($\alpha$,p)$^{16}$O thermonuclear reaction rate and its impact on the isotopic composition of supernova grains (2020)
Journal Article
Meyer, A., de Séréville, N., Laird, A., Hammache, F., Longland, R., Lawson, T., …Tatischeff, V. (in press). Evaluation of the $^{13}$N($\alpha$,p)$^{16}$O thermonuclear reaction rate and its impact on the isotopic composition of supernova grains. Physical Review C,

It has been suggested that hydrogen ingestion into the helium shell of massive stars could lead to high $^{13}$C and $^{15}$N excesses when the shock of a core-collapse supernova passes through its helium shell. This prediction questions the origin o...

Isotopic Signatures of Supernova Nucleosynthesis in Presolar Silicon Carbide Grains of Type AB with Supersolar 14N/15N Ratios (2019)
Journal Article
Hoppe, P., Stancliffe, R. J., Pignatari, M., & Amari, S. (in press). Isotopic Signatures of Supernova Nucleosynthesis in Presolar Silicon Carbide Grains of Type AB with Supersolar 14N/15N Ratios. The Astrophysical journal, 887(1), 10. https://doi.org/10.3847/1538-4357/ab521c

We report high-resolution C, N, Al, Si, and S isotope data of 38 presolar SiC grains of type AB. Seventeen of these grains are of subtype AB1 (14N/15N < 440 = solar) and 20 of subtype AB2 (14N/15N ≥ 440), previously proposed to be mainly from superno...

The s process in rotating low-mass AGB stars. Nucleosynthesis calculations in models matching asteroseismic constraints (2019)
Journal Article
den Hartogh, J., Hirschi, R., Lugaro, M., Doherty, C., Battino, U., Herwig, F., …Eggenberger, P. (2019). The s process in rotating low-mass AGB stars. Nucleosynthesis calculations in models matching asteroseismic constraints. Astronomy and Astrophysics, 629, https://doi.org/10.1051/0004-6361/201935476

Aims. We investigate the s-process during the AGB phase of stellar models whose cores are enforced to rotate at rates consistent with asteroseismology observations of their progenitors and successors. Methods. We calculated new 2M⊙, Z=0.01 models, ro...

A direct measurement of the 17O(α,γ)21Ne reaction in inverse kinematics and its impact on heavy element production (2019)
Journal Article
Taggart, M. P., Akers, C., Laird, A. M., Hager, U., Ruiz, C., Hutcheon, D. A., …Williams, M. (2019). A direct measurement of the 17O(α,γ)21Ne reaction in inverse kinematics and its impact on heavy element production. Physics letters. B, 798, https://doi.org/10.1016/j.physletb.2019.134894

© 2019 The Authors During the slow neutron capture process in massive stars, reactions on light elements can both produce and absorb neutrons thereby influencing the final heavy element abundances. At low metallicities, the high neutron capture rate...

H-He Shell Interactions and Nucleosynthesis in Massive Population III Stars (2019)
Journal Article
Clarkson, O., Herwig, F., Andrassy, R., Woodward, P., Pignatari, M., & Mao, H. (in press). H-He Shell Interactions and Nucleosynthesis in Massive Population III Stars. Springer Proceedings in Physics, 219, 321-325. https://doi.org/10.1007/978-3-030-13876-9_56

© 2019, Springer Nature Switzerland AG. We report on our ongoing investigation into the nucleosynthetic and hydrodynamic nature of mixing at the interface between the H- and He-convection zones in massive Pop III stars. Studying recent a grid of 26 1...

Inhomogeneous Chemical Evolution of r-Process Elements in the Galactic Halo (2019)
Journal Article
Wehmeyer, B., Fröhlich, C., Pignatari, M., & Thielemann, F. K. (in press). Inhomogeneous Chemical Evolution of r-Process Elements in the Galactic Halo. Springer Proceedings in Physics, 219, 91-96. https://doi.org/10.1007/978-3-030-13876-9_15

© 2019, Springer Nature Switzerland AG. The origin of the heaviest elements is still a matter of debate. For the rapid neutron capture process (“r-process”), multiple sites have been proposed, e.g., neutron star mergers and (sub-classes) of supernova...

Heavy Elements Nucleosynthesis on Accreting White Dwarfs Surface: Seeding the p-Process (2019)
Journal Article
Battino, U., Travaglio, C., Pignatari, M., & Lederer-Woods, C. (in press). Heavy Elements Nucleosynthesis on Accreting White Dwarfs Surface: Seeding the p-Process. Springer Proceedings in Physics, 219, 179-182. https://doi.org/10.1007/978-3-030-13876-9_29

© 2019, Springer Nature Switzerland AG. The production of the proton-rich isotopes beyond iron that we observe today in the solar system is still uncertain. Thermonuclear supernovae (SNe Ia) exploding within the single-degenerate scenario have been p...

Presolar SiC Grains of Type AB with Isotopically Light Nitrogen: Contributions from Supernovae? (2019)
Journal Article
Hoppe, P., Pignatari, M., & Amari, S. (2019). Presolar SiC Grains of Type AB with Isotopically Light Nitrogen: Contributions from Supernovae?. Springer Proceedings in Physics, 219, 373-376. https://doi.org/10.1007/978-3-030-13876-9_68

Primitive solar system materials contain presolar grains that formed in the winds of evolved stars and in the ejecta of stellar explosions. Here, we report on NanoSIMS measurements of C-, N-, Al–Mg-, Si-, and S-isotopic compositions of 10 submicromet...

NuGrid stellar data set - III. Updated low-mass AGB models and s-process nucleosynthesis with metallicities Z = 0.01, Z = 0.02, and Z = 0.03 (2019)
Journal Article
Battino, U., Tattersall, A., Lederer-Woods, C., Herwig, F., Denissenkov, P., Hirschi, R., …Pignatari, M. (2019). NuGrid stellar data set - III. Updated low-mass AGB models and s-process nucleosynthesis with metallicities Z = 0.01, Z = 0.02, and Z = 0.03. Monthly notices of the Royal Astronomical Society, 489(1), 1082-1098. https://doi.org/10.1093/mnras/stz2158

© 2019 Oxford University Press. All rights reserved. The production of the neutron-capture isotopes beyond iron that we observe today in the Solar system is the result of the combined contribution of the r-process, the s-process, and possibly the i-p...

The i-process yields of rapidly accreting white dwarfs from multicycle He-shell flash stellar evolution models with mixing parametrizations from 3D hydrodynamics simulations (2019)
Journal Article
Denissenkov, P. A., Herwig, F., Woodward, P., Andrassy, R., Pignatari, M., & Jones, S. (2019). The i-process yields of rapidly accreting white dwarfs from multicycle He-shell flash stellar evolution models with mixing parametrizations from 3D hydrodynamics simulations. Monthly notices, containing papers, abstracts of papers, and reports of the proceedings of the Society, 488(3), 4258-4270. https://doi.org/10.1093/mnras/stz1921

Galactic chemical evolution of radioactive isotopes (2019)
Journal Article
Côté, B., Lugaro, M., Reifarth, R., Pignatari, M., Világos, B., Yagüe, A., & Gibson, B. K. (2019). Galactic chemical evolution of radioactive isotopes. The Astrophysical journal, 878(2), https://doi.org/10.3847/1538-4357/ab21d1

The presence of short-lived (∼ Myr) radioactive isotopes in meteoritic inclusions at the time of their formation represents a unique opportunity to study the circumstances that led to the formation of the Solar System. To interpret these observations...

Using failed supernovae to constrain the Galactic r-process element production (2019)
Journal Article
Wehmeyer, B., Wehmeyer, B., Fröhlich, C., Fröhlich, C., Côté, B., Côté, B., …Thielemann, F. K. (2019). Using failed supernovae to constrain the Galactic r-process element production. Monthly notices, containing papers, abstracts of papers, and reports of the proceedings of the Society, 487(2), 1745-1753. https://doi.org/10.1093/mnras/stz1310

Rapid neutron capture process (r-process) elements have been detected in a large fraction of metal-poor halo stars, with abundances relative to iron (Fe) that vary by over two orders of magnitude. This scatter is reduced to less than a factor of 3 in...

Neutron star mergers might not be the only source of r-process elements in the Milky Way (2019)
Journal Article
Côté, B., Eichler, M., Arcones, A., Hansen, C. J., Simonetti, P., Frebel, A., …Matteucci, F. (2019). Neutron star mergers might not be the only source of r-process elements in the Milky Way. The Astrophysical journal, 875(2), 106. https://doi.org/10.3847/1538-4357/ab10db

Probing the origin of r-process elements in the universe represents a multidisciplinary challenge. We review the observational evidence that probes the properties of r-process sites, and address them using galactic chemical evolution simulations, bin...

Catching element formation in the act (2019)
Other
Fryer, C. L., Timmes, F., Hungerford, A. L., Couture, A., Adams, F., Aoki, W., …Pignatari, M. (2019). Catching element formation in the act

Gamma-ray astronomy explores the most energetic photons in nature to address some of the most pressing puzzles in contemporary astrophysics. It encompasses a wide range of objects and phenomena: stars, supernovae, novae, neutron stars, stellar-mass b...

Enrichment of the Galactic disc with neutron capture elements: Sr (2019)
Journal Article
Mishenina, T., Pignatari, M., Gorbaneva, T., Bisterzo, S., Travaglio, C., Thielemann, F. K., & Soubiran, C. (2019). Enrichment of the Galactic disc with neutron capture elements: Sr. Monthly notices, containing papers, abstracts of papers, and reports of the proceedings of the Society, 484(3), 3846-3864. https://doi.org/10.1093/mnras/stz178

The enrichment history of heavy neutron-capture elements in the Milky Way disc provides fundamental information about the chemical evolution of our Galaxy and about the stellar sources that made those elements. In this work we give new observational...

Nucleosynthetic yields from neutron stars accreting in binary common envelopes (2019)
Journal Article
Keegans, J. D., Fryer, C. L., Jones, S. W., Côté, B., Belczynski, K., Herwig, F., …Diget, C. A. (2019). Nucleosynthetic yields from neutron stars accreting in binary common envelopes. Monthly notices, containing papers, abstracts of papers, and reports of the proceedings of the Society, 485(1), 620-639. https://doi.org/10.1093/mnras/stz368

© 2019 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society. Massive-star binaries can undergo a phase where one of the two stars expands during its advanced evolutionary stage as a giant and envelops its com...

Enrichment of the Galactic disc with neutron-capture elements: Mo and Ru (2019)
Journal Article
Thielemann, F. K., Mishenina, T., Pignatari, M., Gorbaneva, T., Travaglio, C., Côté, B., …Soubiran, C. (2019). Enrichment of the Galactic disc with neutron-capture elements: Mo and Ru. Monthly notices of the Royal Astronomical Society, 489(2), 1697-1708. https://doi.org/10.1093/mnras/stz2202

© 2019 The Author(s). We present new observational data for the heavy elements molybdenum (Mo, Z = 42) and ruthenium (Ru, Z = 44) in F-, G-, and K-stars belonging to different substructures of the Milky Way. The range of metallicity covered is -1.0 <...

Remnants and ejecta of thermonuclear electron-capture supernovae: Constraining oxygen-neon deflagrations in high-density white dwarfs (2018)
Journal Article
Jones, S., Röpke, F. K., Fryer, C., Ruiter, A. J., Seitenzahl, I. R., Nittler, L. R., …Belczynski, K. (2019). Remnants and ejecta of thermonuclear electron-capture supernovae: Constraining oxygen-neon deflagrations in high-density white dwarfs. Astronomy and Astrophysics, 622, https://doi.org/10.1051/0004-6361/201834381

The explosion mechanism of electron-capture supernovae (ECSNe) remains equivocal: it is not completely clear whether these events are implosions in which neutron stars are formed, or incomplete thermonuclear explosions that leave behind bound ONeFe w...

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