Robert Izzard's Pages of Astronomical Happiness

binary_c/nucsyn is the C-version of the Binary Star Evolution (BSE) code of Hurley et al. (2002) (binary_c) with added nucleosynthesis (nucsyn) and enhancements to better include rotation and non-conservative mass transfer.

The nucleosynthesis algorithm, developed during my PhD and subsequent postdocs in Utrecht/Nijmegen and Brussels, runs in parallel to the "stellar evolution" part of the code. Full details can be found in Izzard et al (2004), Izzard et al (2006) and Izzard et al (2009).

The code remains under development in collaboration with many astrophysicists around the world, especially Selma de Mink (ex-Utrecht, ex-Bonn and for now STScI, Baltimore), Tyl Dermine (Brussels) and the Nijmegen (ex-Utrecht) binary-star group, notably Joke Claeys and Carlo Abate.
If you would like to use the code please contact me at the email address given below - the code is not publicly available and is subject to your agreeing to the usage licence.

Binary_c/nucsyn - you'd be a mug not to use it!

Binary_c/nucsyn has a facebook group!

Try the binary_c online yield generator!

binary_c/nucsyn has developed into a complete software package for the modelling of binary stellar evolution, nucleosynthesis, population synthesis and Galactic chemical evolution.

The core package is the binary_c/nycsyn binary stellar evolution and nucleosynthesis code. This can be compiled and run as a standalone unit. The binary_grid.pm runs grids of stars e.g. with different masses, orbital periods etc. It is written in Perl and as such is highly flexible and easy to modify. Many thousands of stars can be run in an hour, millions in a day. The latest versions automatically take advantage of threading on multi-core architectures to speed up calculations. The output can consist of event rates (e.g. supernovae, gamma-ray bursts), number counts (e.g. the number of R or K-type stars) or chemical yields i.e. the amount of material ejected as a particular isotope. I have written a simple one-zone Galactic chemical evolution code which uses binary_c/nucsyn to calculate the chemical history of the Galaxy. It has gas infall and outflow and can be fed an arbitrary star formation history. The same model follows both chemistry and an arbitrary number of stellar observables, such as the number or luminosity of stars as a function of time and/or metallicity.

• First and second dredge-up fitted to the detailed nucleosynthesis models of Karakas, Lattanzio and Pols (2002), Karakas and Lattanzio 2007 and others from Evert Glebbeek and Richard Stancliffe.
• The effects of third dredge-up updated with the models of Karakas and Lattanzio 2007. Free parameters are available to artificially increase the amount of third dredge up, as may be required in the Magellanic clouds or at low metallicity.
• The s-process according to the models of Robert Gallino and collaborators with variable s-process efficiency.
• Hot-bottom burning via the CNO, NeNa and MgAl cycles/chains during the AGB. True nuclear network calculations have replaced the original analytic formalism. The reaction rates can be varied within experimental limits.
• Phenomenological fits to massive and Wolf-Rayet star surface abundances based on the models of Lynnette Dray (Dray et al. 2003) with supplemental models from Richard Stancliffe.
• Supernovae: types Ia, II and Ib/c with yields fitted to published models (Woosley and Weaver 1995, Iwamoto et al. 1999, Arlandini et al. 1999, Simmerer 2004, Livne and Arnett 1995, Woosley, Taam and Weaver 1986, Chieffi and Limongi 2004, Wanaja et al. 2008).
• Nova yields fitted to Jose and Hernanz (1998).
• Roche-Lobe Overflow (RLOF), common-envelope loss contribution to yields.
• Mass loss due to stellar winds and mass gain from a companion's wind (Bondi-Hoyle accretion).
• A momentum-collision argument for treating colliding winds.
• Accretion is treated with a two-layer model assuming either instantaneous or no thermohaline mixing.