Massive Stars as Cosmic Engines through the Ages (2008)
Journal Article
Hirschi, R. (2008). Massive Stars as Cosmic Engines through the Ages. Proceedings of the International Astronomical Union, 3-16. https://doi.org/10.1017/S1743921308020292

Some useful developments in the model physics are briefly presented, followed by model results on chemical enrichments and WR stars. We discuss the expected rotation velocities of WR stars. We emphasize that the (C+O)/He ratio is a better chemical in... Read More about Massive Stars as Cosmic Engines through the Ages.

Nucleosynthesis simulations for a wide range of nuclear production sites from NuGrid (2008)
Journal Article
Herwig, F., Fryer, C., Hirschi, R., Bennett, M., L. Fryer, C., Diehl, S., …Young, P. Nucleosynthesis simulations for a wide range of nuclear production sites from NuGrid. Manuscript submitted for publication

Simulations of nucleosynthesis in astrophysical environments are at the intersection of nuclear physics reaction rate research and astrophysical applications, for example in the area of galactic chemical evolution or near-field cosmology. Unfortunate... Read More about Nucleosynthesis simulations for a wide range of nuclear production sites from NuGrid.

NuGrid: s process in massive stars (2008)
Journal Article
Frischknecht, U., Thielemann, F., -K. Thielemann, F., Pignatari, M., Bennett, M., Diehl, S., …Hirschi, R. NuGrid: s process in massive stars. Manuscript submitted for publication

The s-process production in massive stars at very low metallicities is expected to be negligible due to the low abundance of the neutron source 22Ne, to primary neutron poisons and decreasing iron seed abundances. However, recent models of massive st... Read More about NuGrid: s process in massive stars.

Spatial Distribution of Nucleosynthesis Products in Cassiopeia A: Comparison Between Observations and 3D Explosion Models (2008)
Presentation / Conference
(2008, July). Spatial Distribution of Nucleosynthesis Products in Cassiopeia A: Comparison Between Observations and 3D Explosion Models. Presented at 10th Symposium on Nuclei in the Cosmos, Mackinac Island, Michigan, USA

We examine observed heavy element abundances in the Cassiopeia A supernova remnant as a constraint on the nature of the Cas A supernova. We compare bulk abundances from 1D and 3D explosion models and spatial distribution of elements in 3D models with... Read More about Spatial Distribution of Nucleosynthesis Products in Cassiopeia A: Comparison Between Observations and 3D Explosion Models.

Complete nucleosynthesis calculations for low-mass stars from NuGrid (2008)
Presentation / Conference
(2008, July). Complete nucleosynthesis calculations for low-mass stars from NuGrid. Presented at 10th Symposium on Nuclei in the Cosmos, Mackinac Island, Michigan, USA

Many nucleosynthesis and mixing processes of low-mass stars as they evolve from the Main Sequence to the thermal-pulse Asymptotic Giant Branch phase (TP-AGB) are well understood (although of course important physics components, e.g. rotation, magneti... Read More about Complete nucleosynthesis calculations for low-mass stars from NuGrid.

Nucleosynthesis Calculations from Core-Collapse Supernovae (2008)
Presentation / Conference
(2008, July). Nucleosynthesis Calculations from Core-Collapse Supernovae. Presented at 10th Symposium on Nuclei in the Cosmos, Mackinac Island, Michigan, USA

We review some of the uncertainties in calculating nucleosynthetic yields, focusing on the explosion mechanism. Current yield calculations tend to either use a piston, energy injection, or enhancement of neutrino opacities to drive an explosion. We s... Read More about Nucleosynthesis Calculations from Core-Collapse Supernovae.

The impact of stellar rotation on the CNO abundance patterns in the Milky Way at low metallicities (2008)
Presentation / Conference
(2008, July). The impact of stellar rotation on the CNO abundance patterns in the Milky Way at low metallicities. Presented at 10th Symposium on Nuclei in the Cosmos, Mackinac Island, Michigan, USA

We investigate the effect of new stellar models, which take rotation into account, computed for very low metallicities on the chemical evolution of the earliest phases of the Milky Way. We check the impact of these new stellar yields on a model for t... Read More about The impact of stellar rotation on the CNO abundance patterns in the Milky Way at low metallicities.

Nucleosynthetic Yields from "Collapsars" (2008)
Presentation / Conference
(2008, July). Nucleosynthetic Yields from "Collapsars". Presented at 10th Symposium on Nuclei in the Cosmos, Mackinac Island, Michigan, USA

The "collapsar" engine for gamma-ray bursts invokes as its energy source the failure of a normal supernova and the formation of a black hole. Here we present the results of the first three-dimensional simulation of the collapse of a massive star down... Read More about Nucleosynthetic Yields from "Collapsars".

NuGrid: Toward High Precision Double-Degenerate Merger Simulations with SPH in 3D (2008)
Presentation / Conference
(2008, July). NuGrid: Toward High Precision Double-Degenerate Merger Simulations with SPH in 3D. Presented at 10th Symposium on Nuclei in the Cosmos, Mackinac Island, Michigan, USA

We present preliminary results from recent high-resolution double-degenerate merger simulations with the Smooth Particle Hydrodynamics (SPH) technique. We put particular emphasis on verification and validation in our effort and show the importance of... Read More about NuGrid: Toward High Precision Double-Degenerate Merger Simulations with SPH in 3D.

44Ti and 56Ni in core-collapse supernovae (2008)
Presentation / Conference
Magkotsios, G., Timmes, F. X., Wiescher, M., Fryer, C. L., Hungerford, A., Young, P., …Rockefeller, G. (2008, July). 44Ti and 56Ni in core-collapse supernovae. Paper presented at 10th Symposium on Nuclei in the Cosmos, Mackinac Island, Michigan, USA

We investigate the physical conditions where 44Ti and 56Ni are created in core-collapse supernovae. In this preliminary work we use a series of post-processing network calculations with parametrized expansion profiles that are representative of the w... Read More about 44Ti and 56Ni in core-collapse supernovae.

Difficulties in Probing Nuclear Physics: A Study of Ti and Ni (2008)
Presentation / Conference
Hungerford, A., Fryer, C. L., Timmes, F. X., Young, P., Bennett, M., Diehl, S., …Rockefeller, G. (2008, July). Difficulties in Probing Nuclear Physics: A Study of Ti and Ni. Paper presented at 10th Symposium on Nuclei in the Cosmos, Mackinac Island, Michigan, USA

The nucleosynthetic yield from a supernova explosion depends upon a variety of effects: progenitor evolution, explosion process, details of the nuclear network, and nuclear rates. Especially in studies of integrated stellar yields, simplifications re... Read More about Difficulties in Probing Nuclear Physics: A Study of Ti and Ni.

A survey for low mass spectroscopic binary stars in the young clusters around sigma Orionis and lambda Orionis (2008)
Journal Article
(2008). A survey for low mass spectroscopic binary stars in the young clusters around sigma Orionis and lambda Orionis. Monthly Notices of the Royal Astronomical Society, 2210-2224. https://doi.org/10.1111/j.1365-2966.2008.13008.x

We have obtained multi-epoch, high-resolution spectroscopy of 218 candidate low-mass stars and brown dwarfs in the young clusters around sigma Ori and lambda Ori. We find that 196 targets are cluster members based on their radial velocity, the equiva... Read More about A survey for low mass spectroscopic binary stars in the young clusters around sigma Orionis and lambda Orionis.