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MODEST Working Group 2:
Stellar Evolution


Stars in clusters evolve, and this evolution provides a crucial feedback on the evolution of the cluster as a whole - through mass loss, interaction, and collisions between stars. Conversely, the dynamical cluster environment strongly modifies the evolution of many of its members, and the often exotic stars that result can be an important diagnostic of the (hydro)dynamical processes that take place.

Our challenge is to model the evolution of any star that can be present in a dense cluster, whether single, binary or a member of a higher-order multiple. This includes non-canonical stars that result from stellar mergers and collisions. We thus require a stellar evolution code that can run autonomously from an arbitrary initial configuration to the end of a star's nuclear and thermal evolution. The code should be sufficiently fast so as not grind a cluster simulation to a halt. Above all, it should be robust and give a meaningful result under any conceivable circumstance.


Contact: Onno Pols

Stellar evolution web interfaces

Here are a some links to sites allowing on-the-spot simulations of single and binary stellar evolution, using a parameterized (formula-based) approach to stellar evolution:

Single-star evolution : tutorial and demonstration site, with interface for simulations of evolving single stars, by Charles Gammie et al. at UIUC. Based on the SSE package by Hurley, Pols & Tout (2000, MNRAS 315, 543).

Binary evolution : web interface by Steve McMillan and Simon Portegies Zwart to the SeBa code for simulating binary evolution (Portegies Zwart & Verbunt, 1996, A&A 309, 179).

Links to stellar evolution codes

Full-scale, detailed evolution codes accessible via the web:

STARS : Cambridge stellar evolution code, originally developed by Peter Eggleton

EZ : stripped-down version of the STARS code, rewritten in Fortran90 by Bill Paxton following modern programming practices

Tycho : David Arnett's stellar evolution code

Evolving clusters

M67 simulation : Direct N-body simulation of M67 including parameterized stellar and binary evolution, by Jarrod Hurley et al. (2001, MNRAS 323, 630). A more recent simulation by Jarrod of an M67-like cluster is included in this talk he gave at ITP.

Last modified: Monday 13-Aug-2004