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All Outputs (123)

Progenitors of Core-Collapse Supernovae (2017)
Journal Article
Hirschi, R., Arnett, D., Cristini, A., Georgy, C., Meakin, C., & Walkington, I. (2017). Progenitors of Core-Collapse Supernovae. Proceedings of the International Astronomical Union, 12(S331), 1-10. https://doi.org/10.1017/S1743921317004896

Massive stars have a strong impact on their surroundings, in particular when they produce a core-collapse supernova at the end of their evolution. In these proceedings, we review the general evolution of massive stars and their properties at collapse... Read More about Progenitors of Core-Collapse Supernovae.

Impact of Rotation and Convective Boundary Mixing in Low Mass AGB Stars (2017)
Journal Article
den Hartogh, J., Battino, U., Hirschi, R., Pignatari, M., & Herwig, F. (2017). Impact of Rotation and Convective Boundary Mixing in Low Mass AGB Stars. JPS Conference Proceedings, https://doi.org/10.7566/jpscp.14.020904

After central He burning exhaustion, stars with an initial mass of 1.5–3 solar masses start the AGB phase. In this phase, the s-process takes place, which is producing about half of all elements heavier than iron. We calculated non-rotating AGB stell... Read More about Impact of Rotation and Convective Boundary Mixing in Low Mass AGB Stars.

Impacts of Nuclear-Physics Uncertainty in Stellar Temperatures on the s-Process Nucleosynthesis (2017)
Journal Article
Nishimura, N., Cescutti, G., Hirschi, R., Rauscher, T., Den Hartogh, J., & Murphy, A. S. J. (2017). Impacts of Nuclear-Physics Uncertainty in Stellar Temperatures on the s-Process Nucleosynthesis. JPS Conference Proceedings, https://doi.org/10.7566/jpscp.14.020903

We evaluated the uncertainty relevant to s-process nucleosynthesis using a Monte-Carlo centred approach. We are based on a realistic and general prescription of temperature dependent uncertainty for the reactions. We considered massive stars for the... Read More about Impacts of Nuclear-Physics Uncertainty in Stellar Temperatures on the s-Process Nucleosynthesis.

Constraining the efficiency of angular momentum transport with asteroseismology of red giants: the effect of stellar mass (2017)
Journal Article
Eggenberger, P., Lagarde, N., Miglio, A., Montalbán, J., Ekström, S., Georgy, C., …Hirschi, R. (2017). Constraining the efficiency of angular momentum transport with asteroseismology of red giants: the effect of stellar mass. Astronomy & Astrophysics, 599, Article A18. https://doi.org/10.1051/0004-6361/201629459

Context. Constraints on the internal rotation of red giants are now available thanks to asteroseismic observations. Preliminary comparisons with rotating stellar models indicate that an undetermined additional process for the internal transport of an... Read More about Constraining the efficiency of angular momentum transport with asteroseismology of red giants: the effect of stellar mass.

Massive Star Evolution: What we do (not) know (2016)
Journal Article
Georgy, C., Hirschi, R., & Ekström, S. (2016). Massive Star Evolution: What we do (not) know. Proceedings of the Polish Astronomical Society, 5, 37-44

The modelling of massive star evolution is a complex task, and is very sensitive to the way physical processes (such as convection, rotation, mass loss, etc.) are included in stellar evolution code. Moreover, the very high observed fraction of binary... Read More about Massive Star Evolution: What we do (not) know.

The First 3D Simulations of Carbon Burning in a Massive Star (2016)
Conference Proceeding
Cristini, A., Meakin, C., Hirschi, R., Arnett, D., Georgy, C., & Viallet, M. (2016). The First 3D Simulations of Carbon Burning in a Massive Star. . https://doi.org/10.1017/s1743921317003441

We present the first detailed three-dimensional hydrodynamic implicit large eddy simulations of turbulent convection for carbon burning. The simulations start with an initial radial profile mapped from a carbon burning shell within a 15 M⊙ stellar ev... Read More about The First 3D Simulations of Carbon Burning in a Massive Star.

Fast evolving pair-instability supernova models: evolution, explosion, light curves (2016)
Journal Article
Kozyreva, A., Gilmer, M., Hirschi, R., Fröhlich, C., Blinnikov, S., Wollaeger, R. T., …Sorokina, E. (2017). Fast evolving pair-instability supernova models: evolution, explosion, light curves. Monthly Notices of the Royal Astronomical Society, 464(3), 2854-2865. https://doi.org/10.1093/mnras/stw2562

With an increasing number of superluminous supernovae (SLSNe) discovered, the question of their origin remains open and causes heated debates in the supernova community. Currently, there are three proposed mechanisms for SLSNe: (1) pair-instability s... Read More about Fast evolving pair-instability supernova models: evolution, explosion, light curves.

Looking for imprints of the first stellar generations in metal-poor bulge field stars (2016)
Journal Article
Hirschi. (2016). Looking for imprints of the first stellar generations in metal-poor bulge field stars. Astronomy and Astrophysics, https://doi.org/10.1051/0004-6361/201628104

Context. Efforts to look for signatures of the first stars have concentrated on metal-poor halo objects. However, the low end of the bulge metallicity distribution has been shown to host some of the oldest objects in the Milky Way and hence this Gala... Read More about Looking for imprints of the first stellar generations in metal-poor bulge field stars.

Uncertainties in the production of p nuclei in massive stars obtained from Monte Carlo variations (2016)
Journal Article
Rauscher, T., Nishimura, N., Hirschi, R., Cescutti, G., Murphy, A., & Heger, A. (2016). Uncertainties in the production of p nuclei in massive stars obtained from Monte Carlo variations. Monthly Notices of the Royal Astronomical Society, 463(4), 4153 - 4166. https://doi.org/10.1093/mnras/stw2266

Nuclear data uncertainties in the production of p nuclei in massive stars have been quantified in a Monte Carlo procedure. Bespoke temperature-dependent uncertainties were assigned to different types of reactions involving nuclei from Fe to Bi. Their... Read More about Uncertainties in the production of p nuclei in massive stars obtained from Monte Carlo variations.

Nugrid stellar data set. I. Stellar yields from H to BI for stars with metallicities z=0.02 and z=0.01 (2016)
Journal Article
Hirschi. (2016). Nugrid stellar data set. I. Stellar yields from H to BI for stars with metallicities z=0.02 and z=0.01. Astrophysical Journal Supplement, https://doi.org/10.3847/0067-0049/225/2/24

We provide a set of stellar evolution and nucleosynthesis calculations that applies established physics assumptions simultaneously to low- and intermediate-mass and massive star models. Our goal is to provide an internally consistent and comprehensiv... Read More about Nugrid stellar data set. I. Stellar yields from H to BI for stars with metallicities z=0.02 and z=0.01.

Application of a theory and simulation-based convective boundary mixing model for AGB star evolution and nucleosynthesis (2016)
Journal Article
Battino, U., Pignatari, M., Ritter, C., Herwig, F., Denisenkov, P., Den Hartogh, J., …Paxton, B. (2016). Application of a theory and simulation-based convective boundary mixing model for AGB star evolution and nucleosynthesis. Astrophysical Journal, 827(1), 30. https://doi.org/10.3847/0004-637X/827/1/30

The s-process nucleosynthesis in Asymptotic giant branch (AGB) stars depends on the modeling of convective boundaries. We present models and s-process simulations that adopt a treatment of convective boundaries based on the results of hydrodynamic si... Read More about Application of a theory and simulation-based convective boundary mixing model for AGB star evolution and nucleosynthesis.

Theory considerations for nucleosynthesis beyond Fe with special emphasis on p-nuclei in massive stars (2016)
Journal Article
Rauscher, T., Nishimura, N., & Hirschi, R. (2016). Theory considerations for nucleosynthesis beyond Fe with special emphasis on p-nuclei in massive stars. AIP conference proceedings, 1743(1), https://doi.org/10.1063/1.4953300

Nucleosynthesis of heavy elements requires the use of different experimental and theoretical methods to determine astrophysical reaction rates than light element nucleosynthesis. Additionally, there are also larger uncertainties involved in the astro... Read More about Theory considerations for nucleosynthesis beyond Fe with special emphasis on p-nuclei in massive stars.

Effects of Dimensionality on Pair-Instability Supernova Explosions (2016)
Presentation / Conference
Gilmer, M. S., Kozyreva, A., Hirschi, R., & Fröhlich, C. (2016, June). Effects of Dimensionality on Pair-Instability Supernova Explosions. Paper presented at Proceedings of the 14th International Symposium on Nuclei in the Cosmos (NIC2016), Toki Messe, Niigata, Japan

Since the emergence of the new class of extremely bright transients, super-luminous supernovae (SLSNe), three main mechanisms to power their light curves (LCs) have been discussed. They are the spin-down of a magnetar, interaction with circumstellar... Read More about Effects of Dimensionality on Pair-Instability Supernova Explosions.

Linking 1D evolutionary to 3D hydrodynamical simulations of massive stars (2016)
Journal Article
Hirschi. (2016). Linking 1D evolutionary to 3D hydrodynamical simulations of massive stars. Physica Scripta, 98-99. https://doi.org/10.1017/S1743921314006371

In this contribution we present initial results of a study on convective boundary mixing (CBM) in massive stellar models using the GENEVA stellar evolution code (Eggenberger et al.2008). Before undertaking costly 3D hydrodynamic simulations, it is im... Read More about Linking 1D evolutionary to 3D hydrodynamical simulations of massive stars.

How much radioactive nickel does ASASSN-15lh require? (2016)
Journal Article
Kozyreva, A., Hirschi, R., Blinnikov, S., & den Hartogh, J. (2016). How much radioactive nickel does ASASSN-15lh require?. Monthly Notices of the Royal Astronomical Society, 459(1), L21–L25. https://doi.org/10.1093/mnrasl/slw036

The discovery of the most luminous supernova ASASSN-15lh triggered a shock-wave in the supernova community. The three possible mechanisms proposed for the majority of other superluminous supernovae do not produce a realistic physical model for this p... Read More about How much radioactive nickel does ASASSN-15lh require?.

Linking 1D evolutionary to 3D hydrodynamical simulations of massive stars (2016)
Journal Article
Cristini, A., Meakin, C., Hirschi, R., Arnett, D., Georgy, C., & Viallet, M. (2016). Linking 1D evolutionary to 3D hydrodynamical simulations of massive stars. Physica Scripta, 91(3), 034006. https://doi.org/10.1088/0031-8949/91/3/034006

Stellar evolution models of massive stars are important for many areas of astrophysics, for example nucleosynthesis yields, supernova progenitor models and understanding physics under extreme conditions. Turbulence occurs in stars primarily due to nu... Read More about Linking 1D evolutionary to 3D hydrodynamical simulations of massive stars.

Wolf-Rayet stars as an evolved stage of stellar life (2016)
Conference Proceeding
Georgy, C., Ekström, S., Hirschi, R., Meynet, G., Groh, J., & Eggenberger, P. (2016). Wolf-Rayet stars as an evolved stage of stellar life. In Wolf-Rayet Stars: Proceedings of an International Workshop held in Potsdam, Germany, 1.–5. June 2015

Wolf-Rayet (WR) stars, as they are advanced stages of the life of massive stars, provide a good test for various physical processes involved in the modelling of massive stars, such as rotation and mass loss. In this paper, we show the outputs of the... Read More about Wolf-Rayet stars as an evolved stage of stellar life.

s-process production in rotating massive stars at solar and low metallicities (2015)
Journal Article
Frischknecht, U., Hirschi, R., Pignatari, M., Maeder, A., Meynet, G., Chiappini, C., …Ekström, S. (2016). s-process production in rotating massive stars at solar and low metallicities. Monthly Notices of the Royal Astronomical Society, 456(2), 1803 - 1825. https://doi.org/10.1093/mnras/stv2723

Rotation was shown to have a strong impact on the structure and light element nucleosynthesis in massive stars. In particular, models including rotation can reproduce the primary nitrogen observed in halo extremely metal poor (EMP) stars. Additional... Read More about s-process production in rotating massive stars at solar and low metallicities.

Clues on the first stars from CEMP-no stars (2015)
Journal Article
Choplin, A., Meynet, G., Maeder, A., Hirschi, R., Ekström, S., & Chiappini, C. (2015). Clues on the first stars from CEMP-no stars. Proceedings of the International Astronomical Union, 11(S317), 282-283. https://doi.org/10.1017/s1743921315006808

The material used to form the CEMP-no stars presents signatures of processing by the CNO cycle and by He-burning from a previous stellar generation called spinstars. We compare the composition of the ejecta (wind + supernova) of a spinstar model to o... Read More about Clues on the first stars from CEMP-no stars.