Outputs (123)

The Formation of a 70 M ? Black Hole at High Metallicity (2020)
Journal Article
Hirschi. (2020). The Formation of a 70 M ? Black Hole at High Metallicity. Astrophysical Journal, 113 -113. https://doi.org/10.3847/1538-4357/ab6d77

A 70 black hole (BH) was discovered in the Milky Way disk in a long-period detached binary system (LB-1) with a high-metallicity 8 B star companion. Current consensus on the formation of BHs from high-metallicity stars limits the BH mass to be below... Read More about The Formation of a 70 M ? Black Hole at High Metallicity.

The s process in rotating low-mass AGB stars - Nucleosynthesis calculations in models matching asteroseismic constraints (2019)
Journal Article
Hirschi. (2019). The s process in rotating low-mass AGB stars - Nucleosynthesis calculations in models matching asteroseismic constraints. Astronomy and Astrophysics, A123 -A123. 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 2 M?, Z = 0.01 mode... Read More about The s process in rotating low-mass AGB stars - Nucleosynthesis calculations in models matching asteroseismic constraints.

The contribution from rotating massive stars to the enrichment in Sr and Ba of the Milky Way (2019)
Journal Article
Rizzuti, F., Cescutti, G., Matteucci, F., Chieffi, A., Hirschi, R., & Limongi, M. (2019). The contribution from rotating massive stars to the enrichment in Sr and Ba of the Milky Way. Monthly Notices of the Royal Astronomical Society, 489(4), 5244 -5255. https://doi.org/10.1093/mnras/stz2505

Most neutron capture elements have a double production by r- and s-processes, but the question of production sites is complex and still open. Recent studies show that including stellar rotation can have a deep impact on nucleosynthesis. We studied th... Read More about The contribution from rotating massive stars to the enrichment in Sr and Ba of the Milky Way.

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.

3D Simulations and MLT. I. Renzini’s Critique (2019)
Journal Article
Arnett, W. D., Meakin, C., Hirschi, R., Cristini, A., Georgy, C., Campbell, S., …Mocák, M. (2019). 3D Simulations and MLT. I. Renzini’s Critique. Astrophysical Journal, 882(1), 18. https://doi.org/10.3847/1538-4357/ab21d9

Renzini wrote an influential critique of “overshooting” in mixing-length theory (MLT), as used in stellar evolution codes, and concluded that three-dimensional fluid dynamical simulations were needed. Such simulations are now well tested. Implicit la... Read More about 3D Simulations and MLT. I. Renzini’s Critique.

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.

Relative Importance of Convective Uncertainties (2019)
Conference Proceeding
Kaiser, E. A., Hirschi, R., Arnett, W. D., Cristini, A., Georgy, C., & Scott, L. J. A. (2019). Relative Importance of Convective Uncertainties. . https://doi.org/10.1007/978-3-030-13876-9_71

Convection plays a key role in the evolution of stars due to energy transport and mixing of composition. Despite its importance, this process is still not well understood. One longstanding conundrum in all 1D stellar evolution codes is the treatment... Read More about Relative Importance of Convective Uncertainties.

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.

Constraining transport of angular momentum in stars Combining asteroseismic observations of core helium burning stars and white dwarfs (2019)
Journal Article
den Hartogh, J., Eggenberger, P., & Hirschi, R. (2019). Constraining transport of angular momentum in stars Combining asteroseismic observations of core helium burning stars and white dwarfs. Astronomy & Astrophysics, 622, 1-10. https://doi.org/10.1051/0004-6361/201834330

Context Transport of angular momentum has been a challenging topic within the stellar evolution community, even more since the recent asteroseismic surveys. All published studies on rotation using asteroseismic observations show a discrepancy betwee... Read More about Constraining transport of angular momentum in stars Combining asteroseismic observations of core helium burning stars and white dwarfs.