A direct measurement of the 17O(a,?)21Ne reaction in inverse kinematics and its impact on heavy element production (2019)
Journal Article
Taggart, M., Akers, C., Laird, A., Hager, U., Ruiz, C., Hutcheon, D., …Williams, M. (2019). A direct measurement of the 17O(a,?)21Ne reaction in inverse kinematics and its impact on heavy element production. Physics Letters B, 798(10), Article 134894. https://doi.org/10.1016/j.physletb.2019.134894

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 of 16O can inhibit... Read More about A direct measurement of the 17O(a,?)21Ne reaction in inverse kinematics and its impact on heavy element production.

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., …Collaboration, T. N. (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

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-process. Low-mass asymptotic giant branch (AGB) (1.5 &... Read More about 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.

Uncertainties in νp-process nucleosynthesis from Monte Carlo variation of reaction rates (2019)
Journal Article
Nishimura (西村信哉), N., Rauscher, T., Hirschi, R., Hirschi, R., Cescutti, G., Murphy, A. S. J., & Fröhlich, C. (2019). Uncertainties in νp-process nucleosynthesis from Monte Carlo variation of reaction rates. Monthly Notices of the Royal Astronomical Society, 489(1), 1379-1396. https://doi.org/10.1093/mnras/stz2104

It has been suggested that a ?p process can occur when hot, dense, and proton-rich matter is expanding within a strong flux of anti-neutrinos. In such an environment, proton-rich nuclides can be produced in sequences of proton captures and (n, p) rea... Read More about Uncertainties in νp-process nucleosynthesis from Monte Carlo variation of reaction rates.

Grids of stellar models with rotation IV. Models from 1.7 to 120 M-circle dot at a metallicity Z=0.0004 (2019)
Journal Article
Groh, J., Ekström, S., Georgy, C., Meynet, G., Choplin, A., Eggenberger, P., …Farrell, E. (2019). Grids of stellar models with rotation IV. Models from 1.7 to 120 M-circle dot at a metallicity Z=0.0004. Astronomy & Astrophysics, 627, Article A24. https://doi.org/10.1051/0004-6361/201833720

The effects of rotation on stellar evolution are particularly important at low metallicity, when mass loss by stellar winds diminishes and the surface enrichment due to rotational mixing becomes relatively more pronounced than at high metallicities.... Read More about Grids of stellar models with rotation IV. Models from 1.7 to 120 M-circle dot at a metallicity Z=0.0004.

Dependence of convective boundary mixing on boundary properties and turbulence strength (2019)
Journal Article
Cristini, A., Hirschi, R., Meakin, C., Arnett, D., Georgy, C., & Walkington, I. (2019). Dependence of convective boundary mixing on boundary properties and turbulence strength. Monthly Notices of the Royal Astronomical Society, 484(4), 4645 - 4664. https://doi.org/10.1093/mnras/stz312

Convective boundary mixing is one of the major uncertainties in stellar evolution. In order to study its dependence on boundary properties and turbulence strength in a controlled way, we computed a series of 3D hydrodynamical simulations of stellar c... Read More about Dependence of convective boundary mixing on boundary properties and turbulence strength.

Non-standard s-process in massive rotating stars (2018)
Journal Article
Hirschi, R. (2018). Non-standard s-process in massive rotating stars. Astronomy and Astrophysics, https://doi.org/10.1051/0004-6361/201833283

Context
Recent studies show that rotation significantly affects the s-process in massive stars.

Aims
We provide tables of yields for non-rotating and rotating massive stars between 10 and 150 M? at Z = 10-3 ([Fe/H] = -1.8). Tables for different... Read More about Non-standard s-process in massive rotating stars.

NuGrid Stellar Data Set. II. Stellar Yields from H to Bi for Stellar Models with MZAMS = 1 to 25 M? and Z = 0.0001 to 0.02 (2018)
Journal Article
Ritter, C., Herwig, F., Jones, S., Pignatari, M., Fryer, C., & Hirschi, R. (2018). NuGrid Stellar Data Set. II. Stellar Yields from H to Bi for Stellar Models with MZAMS = 1 to 25 M? and Z = 0.0001 to 0.02. Monthly Notices of the Royal Astronomical Society, 480(1), 538-571. https://doi.org/10.1093/mnras/sty1729

We provide here a significant extension of the NuGrid Set 1 models in mass coverage and toward lower metallicity, adopting the same physics assumptions. The combined data set now includes the initial masses MZAMS/?M? = 1, 1.65, 2, 3, 4, 5, 6, 7, 12,... Read More about NuGrid Stellar Data Set. II. Stellar Yields from H to Bi for Stellar Models with MZAMS = 1 to 25 M? and Z = 0.0001 to 0.02.

OGLE14-073 – a promising pair-instability supernova candidate (2018)
Journal Article
Kozyreva, A., Kromer, M., Noebauer, U. M., & Hirschi, R. (2018). OGLE14-073 – a promising pair-instability supernova candidate. Monthly Notices of the Royal Astronomical Society, 479(3), 3106 - 3114. https://doi.org/10.1093/mnras/sty983

The recently discovered bright Type? II supernova OGLE14-073 evolved very slowly. The light curve rose to maximum for 90?d from discovery and then declined at a rate compatible with the radioactive decay of 56Co. In this study, we show that a pair-in... Read More about OGLE14-073 – a promising pair-instability supernova candidate.

Uncertainties in s -process nucleosynthesis in low mass stars determined from Monte Carlo variations (2018)
Journal Article
Cescutti, G., Hirschi, R., Nishimura, N., den Hartogh, J. W., Rauscher, T., Murphy, A. S. J., & Cristallo, S. (2018). Uncertainties in s -process nucleosynthesis in low mass stars determined from Monte Carlo variations. Monthly Notices of the Royal Astronomical Society, 478(3), 4101-4127. https://doi.org/10.1093/mnras/sty1185

The main s-process taking place in low mass stars produces about half of the elements heavier than iron. It is therefore very important to determine the importance and impact of nuclear physics uncertainties on this process. We have performed extensi... Read More about Uncertainties in s -process nucleosynthesis in low mass stars determined from Monte Carlo variations.

Sensitivity to neutron captures and ß -decays of the enhanced s-process in rotating massive stars at low metallicities (2018)
Journal Article
Hirschi. (2018). Sensitivity to neutron captures and ß -decays of the enhanced s-process in rotating massive stars at low metallicities. Journal of Physics: Conference Series, 12051. https://doi.org/10.1088/1742-6596/940/1/012051

The s-process in massive stars, producing nuclei up to A ˜ 90, has a different behaviour at low metallicity if stellar rotation is significant. This enhanced s-process is distinct from the s-process in massive stars around solar metallicity, and deta... Read More about Sensitivity to neutron captures and ß -decays of the enhanced s-process in rotating massive stars at low metallicities.

Impact of rotation and magnetic fields in low mass AGB stars (2018)
Conference Proceeding
den Hartogh, J. W., Hirschi, R., Georgy, C., Eggenberger, P., Herwig, F., Pignatari, M., …Ritter, C. (2018). Impact of rotation and magnetic fields in low mass AGB stars. . https://doi.org/10.1088/1742-6596/940/1/012038

After core helium burning in low and intermediate-mass stars, starts the AGB phase. In this phase, the s process takes place, which is believed to be at the origin of half of all elements heavier than iron. The role of rotation and magnetic fields on... Read More about Impact of rotation and magnetic fields in low mass AGB stars.

Nucleosynthesis in the first massive stars (2018)
Journal Article
Hirschi. (2018). Nucleosynthesis in the first massive stars. Journal of Physics: Conference Series, 012021 -?. https://doi.org/10.1088/1742-6596/940/1/012021

The nucleosynthesis in the first massive stars may be constrained by observing the surface composition of long-lived very iron-poor stars born around 10 billion years ago from material enriched by their ejecta. Many interesting clues on physical proc... Read More about Nucleosynthesis in the first massive stars.

Uncertainties in the production of p nuclides in thermonuclear supernovae determined by Monte Carlo variations (2017)
Journal Article
Nishimura(西村信哉), N., Rauscher, T., Hirschi, R., Murphy, A. S. J., Cescutti, G., & Travaglio, C. (2018). Uncertainties in the production of p nuclides in thermonuclear supernovae determined by Monte Carlo variations. Monthly Notices of the Royal Astronomical Society, 474(3), 3133 -3139. https://doi.org/10.1093/mnras/stx3033

Thermonuclear supernovae originating from the explosion of a white dwarf accreting mass from a companion star have been suggested as a site for the production of p nuclides. Such nuclei are produced during the explosion, in layers enriched with seed... Read More about Uncertainties in the production of p nuclides in thermonuclear supernovae determined by Monte Carlo variations.

Are some CEMP-s stars the daughters of spinstars? (2017)
Journal Article
Choplin, A., Hirschi, R., Meynet, G., & Ekström, S. (2017). Are some CEMP-s stars the daughters of spinstars?. Astronomy and Astrophysics, 607, Article L3. https://doi.org/10.1051/0004-6361/201731948

Carbon-enhanced metal-poor (CEMP)-s stars are long-lived low-mass stars with a very low iron content as well as overabundances of carbon and s-elements. Their peculiar chemical pattern is often explained by pollution from an asymptotic giant branch (... Read More about Are some CEMP-s stars the daughters of spinstars?.

Pre-supernova mixing in CEMP-no source stars (2017)
Journal Article
Choplin, A., Ekström, S., Meynet, G., Maeder, A., Georgy, C., & Hirschi, R. (2017). Pre-supernova mixing in CEMP-no source stars. Astronomy & Astrophysics, 605, A63 -A63. https://doi.org/10.1051/0004-6361/201630182

Context. CEMP-no stars are long-lived low-mass stars with a very low iron content, overabundances of carbon and no or minor signs for the presence of s- or r-elements. Although their origin is still a matter of debate, they are often considered as be... Read More about Pre-supernova mixing in CEMP-no source stars.

Pair-instability Supernova Simulations: Progenitor Evolution, Explosion, and Light Curves (2017)
Journal Article
Hirschi, R. (2017). Pair-instability Supernova Simulations: Progenitor Evolution, Explosion, and Light Curves. Astrophysical Journal, 100 - 100. https://doi.org/10.3847/1538-4357/aa8461

In recent years, the viability of the pair-instability supernova (PISN) scenario for explaining superluminous supernovae has all but disappeared except for a few slowly-evolving examples. However, PISNe are not predicted to be superluminous throughou... Read More about Pair-instability Supernova Simulations: Progenitor Evolution, Explosion, and Light Curves.

Testing a one-dimensional prescription of dynamical shear mixing with a two-dimensional hydrodynamic simulation (2017)
Journal Article
Edelman, P., Röpke, F., Hirschi, R., Georgy, C., & Jones, S. (2017). Testing a one-dimensional prescription of dynamical shear mixing with a two-dimensional hydrodynamic simulation. Astronomy and Astrophysics, 604, Article A25. https://doi.org/10.1051/0004-6361/201629873

Context. The treatment of mixing processes is still one of the major uncertainties in 1D stellar evolution models. This is mostly due to the need to parametrize and approximate aspects of hydrodynamics in hydrostatic codes. In particular, the effect... Read More about Testing a one-dimensional prescription of dynamical shear mixing with a two-dimensional hydrodynamic simulation.

3D hydrodynamic simulations of carbon burning in massive stars (2017)
Journal Article
Cristini, A., Meakin, C., Hirschi, R., Arnett, D., Georgy, C., Viallet, M., & Walkington, I. (2017). 3D hydrodynamic simulations of carbon burning in massive stars. Monthly Notices of the Royal Astronomical Society, 471(1), 279 -300. https://doi.org/10.1093/mnras/stx1535

We present the first detailed 3D hydrodynamic implicit large eddy simulations of turbulent convection of carbon burning in massive stars. Simulations begin with radial profiles mapped from a carbon-burning shell within a 15M circle dot 1D stellar evo... Read More about 3D hydrodynamic simulations of carbon burning in massive stars.

The neutron capture process in the He shell in core-collapse suprenovae: Presolar silicon carbide grains as a diagnostic tool for nuclear astrophysics (2017)
Journal Article
Pignatari, M., Hoppe, P., Trappitsch, R., Fryer, C., Timmes, F., Herwig, F., & Hirschi, R. (2017). The neutron capture process in the He shell in core-collapse suprenovae: Presolar silicon carbide grains as a diagnostic tool for nuclear astrophysics. Geochimica et Cosmochimica Acta, 221, 37-46. https://doi.org/10.1016/j.gca.2017.06.005

Carbon-rich presolar grains are found in primitive meteorites, with isotopic measurements to date suggesting a core-collapse supernovae origin site for some of them. This holds for about 1–2% of presolar silicon carbide (SiC) grains, so-called Type X... Read More about The neutron capture process in the He shell in core-collapse suprenovae: Presolar silicon carbide grains as a diagnostic tool for nuclear astrophysics.

Uncertainties in s-process nucleosynthesis in massive stars determined by Monte Carlo variations (2017)
Journal Article
Nishimura (西村信哉), N., Hirschi, R., Rauscher, T., Murphy, A., & Cescutti, G. (2017). Uncertainties in s-process nucleosynthesis in massive stars determined by Monte Carlo variations. Monthly Notices of the Royal Astronomical Society, 469(2), 1752 -1767. https://doi.org/10.1093/mnras/stx696

The s-process in massive stars produces the weak component of the s-process (nuclei up to A ~ 90), in amounts that match solar abundances. For heavier isotopes, such as barium, production through neutron capture is significantly enhanced in very meta... Read More about Uncertainties in s-process nucleosynthesis in massive stars determined by Monte Carlo variations.