Cyberhubs: Virtual Research Environments for Astronomy

Herwig, Falk; Andrássy, Róbert; Annau, N.; Clarkson, Ondrea; Côté, Benoît; D’Sa, Aaron; Jones, S.; Moa, Belaid; O’Connell, Joe; Porter, David H.; Ritter, Christian; Woodward, Paul R.

doi:10.3847/1538-4365/aab777

Cited by 15 publications

(9 citation statements)

References 18 publications

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“…Documentation on how to use the codes is provided in the form of iPython Jupyter notebooks and is cited in the following subsections. Although installing the code is relatively straightforward, the installation can be bypassed by using the online virtual cyberhubs 3 environment (Herwig et al 2018).…”

Section: Chemical Evolution Codesmentioning

confidence: 99%

Galactic Chemical Evolution of Radioactive Isotopes

Côté

Lugaro

Reifarth

et al. 2019

ApJ

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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 we need to calculate the evolution of radioactive-to-stable isotopic ratios in the Galaxy. We present an extension of the open-source galactic chemical evolution codes NuPyCEE and JINAPyCEE that enables to track the decay of radioactive isotopes in the interstellar medium. We show how the evolution of isotopic ratio depends on the star formation history and efficiency, star-to-gas mass ratio, and galactic outflows. Given the uncertainties in the observations used to calibrate our model, our predictions for isotopic ratios at the time of formation of the Sun are uncertain by a factor of 3.6. At that time, to recover the actual radioactive-to-stable isotopic ratios predicted by our model, one can multiply the steady-state solution (see Equation 1) by 2.3 +3.4 −0.7 . However, in the cases where the radioactive isotope has a half-life longer than ∼ 200 Myr, or the target radioactive or stable isotopes have mass-and/or metallicity-depended production rates, or they originate from different sources with different delay-time distributions, or the reference isotope is radioactive, our codes should be used for more accurate solutions. Our preliminary calculations confirm the dichotomy between radioactive nuclei in the early Solar System with r-and s-process origin, and that 55 Mn and 60 Fe can be explained by galactic chemical evolution, while 26 Al cannot.

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Section: Chemical Evolution Codesmentioning

confidence: 99%

Galactic Chemical Evolution of Radioactive Isotopes

Côté

Lugaro

Reifarth

et al. 2019

ApJ

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“…Near [Fe/H] = 0, our predictions (solid line) have a bump that overestimates disk data by almost an order of magnitude. The 20 M stellar model at Z = 0.01 is at the origin of the Cr bump (see also Figure 7 in Herwig et al 2018). When removing this stellar model from the yields set, the bump disappears entirely (dashed line in Figure 1).…”

Section: Galactic Chemical Evolution Modelmentioning

confidence: 93%

“…Here we discuss the impact of silicon-carbon (Si-C) shell mergers on the evolution of chromium (Cr) in the Milky Way. Since the publication of the second set of NuGrid yields (Ritter et al 2018b), an overproduction of Cr at galactic scale has been reported by Herwig et al (2018) and Philcox et al (2018) when using these yields in GCE codes. We have isolated the source of this overproduction.…”

Section: Introductionmentioning

confidence: 99%

Chromium Nucleosynthesis and Silicon–Carbon Shell Mergers in Massive Stars

Côté

Jones

Herwig

et al. 2020

ApJ

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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 predicted by our Milky Way model originates from the merging of convective Si-burning and C-burning shells in a 20 M model at metallicity Z = 0.01, about an hour before the star explodes. This merger mixes the incomplete burning material in the Si shell, including 51 V and 52 Cr, out to the edge of the carbon/oxygen (CO) core. The adopted supernova model ejects the outer 2 M of the CO core, which includes a significant fraction of the Cr-rich material. When including this 20 M model at Z = 0.01 in the yields interpolation scheme of our GCE model for stars in between 15 and 25 M , we overestimate [Cr/Fe] by an order of magnitude at [Fe/H] ≈ 0 relative to observations in the Galactic disk. This raises a number of questions regarding the occurrence of Si-C shell mergers in nature, the accuracy of different simulation approaches, and the impact of such mergers on the pre-supernova structure and explosion dynamics. According to the conditions in this 1D stellar model, the substantial penetration of C-shell material into the Si-shell could launch a convective-reactive global oscillation, if a merger does take place. In any case, GCE provides stringent constraints on the outcome of this stellar evolution phase.

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“…[45]. The calculations were performed using the post-processing nucleosynthesis code MPPNP [46], which was developed by the NuGrid collaboration. The code takes as an input the stellar evolution trajectories calculated by the one-dimensional stellar evolution code MESA [84].…”

Section: Astrophysical Implicationsmentioning

confidence: 99%

“…[45]. For the simulations, we used a multi-zone postprocessing code, MPPNP [46], to study the sensitivity at various stellar masses and initial metallicities. The simulations also demonstrate, in a more general way, the sensitivity of the abundance to the ambiguous reaction rates, by varying the α cluster strength of relevant 22 Ne + α resonances.…”

Section: Introductionmentioning

confidence: 99%

Study of ($^6$Li, $d$) and ($^6$Li, $t$) reactions on $^{22}$Ne and implications for $s$-process nucleosynthesis

Ota,

Christian,

Catford

et al. 2021

Preprint

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We studied α cluster states in 26 Mg via the 22 Ne( 6 Li,dγ) 26 Mg reaction in inverse kinematics at an energy of 7 MeV/nucleon. States between Ex = 4 -12 MeV in 26 Mg were populated and relative α spectroscopic factors were determined. Some of these states correspond to resonances in the Gamow window of the 22 Ne(α,n) 25 Mg reaction, which is one of the main neutron sources in the astrophysical s-process. We show that α-cluster strength of the states analyzed in this work have critical impact on s-process abundances. Using our new 22 Ne(α,n) 25 Mg and 22 Ne(α,γ) 26 Mg reaction rates, we performed new s-process calculations for massive stars and Asymptotic Giant Branch stars and compared the resulting yields with the yields obtained using other 22 Ne+α rates from the literature. We observe an impact on the s-process abundances up to a factor of three for intermediate-mass AGB stars and up to a factor of ten for massive stars. Additionally, states in 25 Mg at Ex < 5 MeV are identified via the 22 Ne( 6 Li,t) 25 Mg reaction for the first time. We present the ( 6 Li, t) spectroscopic factors of these states and note similarities to the (d, p) reaction in terms of reaction selectivity.

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Cyberhubs: Virtual Research Environments for Astronomy

Cited by 15 publications

References 18 publications

Galactic Chemical Evolution of Radioactive Isotopes

Galactic Chemical Evolution of Radioactive Isotopes

Chromium Nucleosynthesis and Silicon–Carbon Shell Mergers in Massive Stars

Study of ($^6$Li, $d$) and ($^6$Li, $t$) reactions on $^{22}$Ne and implications for $s$-process nucleosynthesis

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