Stellar Evolution code: TYCHO

TYCHO: A Stellar Evolution code for the 21st Century

Tycho Brahe was the first astronomer to determine the distance to a supernova. In November 1572 a new star, or nova, appeared in the constellation Cassiopea; in modern terminology this was a supernova in our own Milky Way galaxy. From his own careful observations, this 26-year-old, eccentric Danish nobleman became convinced that this new object (now called Tycho's supernova) was in the supposedly immutable celestial regions. The supernova lay beyond the limits of the solar system as then known, so that the "eternal heavens" were not really unchanging. The medieval cosmology never recovered.

The TYCHO stellar evolution code derives from previous work on supernovae, see Arnett, D., Supernovae and Nucleosynthesis, 1996, Princeton University Press, for discussion and references. It is part of an ongoing project to develop computational tools to study the evolution of stars, from birth to death.

The US pronunciation is "tie ko" although the original Danish might have been closer to "two ko".

The photo of the statue of Tycho (right) was taken by W. D. Arnett in Prague CZ, August 2006. The photo of the supernova remnant (left) is a composite taken from observations of the Chandra X-ray Observatory (NASA/CXC/Rutgers/J.Warren & J.Hughes et al.); the purple lines near the edge of the remnant are highly dissipative shocks in which cosmic rays are being accelerated.


TYCHO is designed to be a stellar evolution code for the 21st Century. It is a general, one dimensional (spherically symmetric) stellar evolution code, designed for hydrostatic and hydrodynamic stages (including mass loss, accretion, pulsations and explosions, using state of the art procedures and microphysics. Mixing and convection algorithms are being based on 3D time-dependent simulations

TYCHO7 is now (4/2008) in beta-test. It is being used in our core graduate course in Stellar Evolution and Nucleosynthesis ASTRO 535/587 at Steward Observatory.

TYCHO is being used for ongoing research in stellar evolution. For recent work, see Young, et al. 2006, ApJ 640, 891. TYCHO provided the initial (low noise) models for Meakin, C. & Arnett, D., 2007, ApJ 667, 448.

TYCHO Users Manual

TYCHO is not public domain software, but is freely available for non-commercial purposes. Absolutely no guarantee is given; use at your own risk...

Last updated 1-4-02