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.

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.

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".

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.

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.

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.

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.

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.

Developments in physics of massive stars (2007)
Conference Proceeding
Meynet, G., Ekström, S., Maeder, A., Hirschi, R., Georgy, C., & Beffa, C. (2007). Developments in physics of massive stars. . https://doi.org/10.1017/S1743921308020449

New constraints on stellar models are provided by large surveys of massive stars, interferometric observations and asteroseismology. After a review of the main results so far obtained, we present new results from rotating models and discuss compariso... Read More about Developments in physics of massive stars.

The ultra-compact binary candidate KUV 23182+1007 is a bright quasar (2007)
Journal Article
Southworth, J., Schwope, A., Gaensicke, B., & Schreiber, M. (2007). The ultra-compact binary candidate KUV 23182+1007 is a bright quasar. arXiv,

KUV 23182+1007 was identified as a blue object in the Kiso UV Survey in the 1980s. Classification-dispersion spectroscopy showed a featureless continuum except for a strong emission line in the region of He II 4686 A. This is a hallmark of the rare A... Read More about The ultra-compact binary candidate KUV 23182+1007 is a bright quasar.

The Keele–Exeter young cluster survey – I. Low-mass pre-main-sequence stars in NGC 2169 (2007)
Journal Article
Jeffries, R., Oliveira, J., Naylor, T., Mayne, N., & Littlefair, S. (2007). The Keele–Exeter young cluster survey – I. Low-mass pre-main-sequence stars in NGC 2169. Monthly Notices of the Royal Astronomical Society, 376(2), 580 -598. https://doi.org/10.1111/j.1365-2966.2007.11327.x

We have used R_C I_C CCD photometry from the Isaac Newton telescope and intermediate resolution spectroscopy from the Gemini North telescope to identify and characterise low-mass (0.15<M/M_sun<1.3) pre-main sequence stars in the young open cluster NG...

Stellar Fluxes as Probes of Convection in Stellar Atmospheres (2006)
Journal Article
Smalley, B. Stellar Fluxes as Probes of Convection in Stellar Atmospheres. https://doi.org/10.1017/S1743921307000300. Manuscript submitted for publication

Convection and turbulence in stellar atmospheres have a significant effect on the emergent flux from late-type stars. The theoretical advancements in convection modelling over recent years have proved challenging for the observers to obtain measureme... Read More about Stellar Fluxes as Probes of Convection in Stellar Atmospheres.

Kinematic structure in the young σ Orionis association (2006)
Journal Article
Jeffries, R., Maxted, P., Oliveira, J., & Naylor, T. (2006). Kinematic structure in the young σ Orionis association. Monthly Notices of the Royal Astronomical Society, 371(1), L6 - L10. https://doi.org/10.1111/j.1745-3933.2006.00196.x

We have used precise radial velocity measurements for a large number of candidate low-mass stars and brown dwarfs, to show that the young Sigma Ori ``cluster'' consists of two spatially superimposed components which are kinematically separated by 7 k... Read More about Kinematic structure in the young σ Orionis association.

Testing convection in stellar models using detached eclipsing binaries (2006)
Presentation / Conference
(2006, August). Testing convection in stellar models using detached eclipsing binaries. Presented at IAUS 239 (Convection in Astrophysics), Prague

The fundamental properties of detached eclipsing binary stars can be measured very accurately, which could make them important objects for constraining the treatment of convection in theoretical stellar models. However, only four or five pieces of in... Read More about Testing convection in stellar models using detached eclipsing binaries.

Very low metallicity massive star models: Pre-SN evolution and primary nitrogen production (2006)
Journal Article
Hirschi, R. Very low metallicity massive star models: Pre-SN evolution and primary nitrogen production. https://doi.org/10.1051/0004-6361%3A20065356. Manuscript submitted for publication

Two series of models were computed. The first series consists of 20 solar mass models with varying initial metallicity (Z=0.02 down to Z=10^{-8}) and rotation (V_{ini}=0-600 km/s). The second one consists of models with an initial metallicity of Z=10... Read More about Very low metallicity massive star models: Pre-SN evolution and primary nitrogen production.

Eclipsing Binaries in Open Clusters (2006)
Journal Article
Southworth, J., & Viggo Clausen, J. (2006). Eclipsing Binaries in Open Clusters. Astrophysics and Space Science, 304, Article 199–202. https://doi.org/10.1007/s10509-006-9110-3

Detached eclipsing binaries are very useful objects for calibrating theoretical stellar models and checking their predictions. Detached eclipsing binaries in open clusters are particularly important because of the additional constraints on their age... Read More about Eclipsing Binaries in Open Clusters.

Circumstellar discs in the young σ Orionis cluster (2006)
Journal Article
Oliveira, J., Jeffries, R., Van Loon, J., & Rushton, M. (2006). Circumstellar discs in the young σ Orionis cluster. Monthly Notices of the Royal Astronomical Society, 369(1), 272 -280. https://doi.org/10.1111/j.1365-2966.2006.10299.x

We present new K- and L'-band imaging observations for members of the young (3-5 Myr) sigma Orionis cluster, obtained with UIST at UKIRT. We determine (K-L') colour excesses with respect to the photospheres, finding evidence for warm circumstellar du... Read More about Circumstellar discs in the young σ Orionis cluster.

Synthesis of the Beryllium 3131A Spectral Region (2005)
Journal Article
Ashwell, J., F. Ashwell, J., Jeffries, R., D. Jeffries, R., & Smalley, B. Synthesis of the Beryllium 3131A Spectral Region. Manuscript submitted for publication

The Beryllium spectral region of the Sun, Procyon and 4 stars in the open cluster NGC6633 up to Teff = 7500K have been synthesised using ATLAS9 model atmospheres and the MOOG spectral synthesis program. The line list used for these syntheses has bee... Read More about Synthesis of the Beryllium 3131A Spectral Region.

Different convection models in ATLAS (2005)
Journal Article
Smalley, B. Different convection models in ATLAS. Manuscript submitted for publication

Convection is an important phenomenon in the atmospheres of A-type and cooler stars. A description of convection in ATLAS models is presented, together with details of how it is specified in model calculations. The effects of changing the treatment o... Read More about Different convection models in ATLAS.

Teff and log g Determinations (2005)
Journal Article
Smalley, B. Teff and log g Determinations. Manuscript submitted for publication

A discussion on the determination of effective temperature (Teff) and surface gravity (log g) is presented. The observational requirements for model-independent fundamental parameters are summarized, including an assessment of the accuracy of these v... Read More about Teff and log g Determinations.