The High-Density Nuclear Equation of State

as visualized by Todd Thompson

We have constructed a table from the Lattimer-Swesty equation of state (see refs. below) to be used in fully dynamical core-collapse simulations. The table consists of 180 evenly-spaced mesh points in log10[], 180 mesh points in log10[T], and 50 mesh points in the electron fraction (Ye). At each point in the table we include the energy per baryon (E) in MeV, the pressure (P) in MeV fm-3, the entropy (s) in units of kB, the specific heat (CV) in baryon-1, =d(lnP)/d(ln)|s, the number fractions Xn, Xp, X, and Xh, the difference µnp, and its derivatives with respect to temperature and Ye. In addition, for the representative heavy nucleus, we also include the atomic mass (A) and the ratio Z/A.

To facillitate visualization of this three dimensional space we have constructed movies of a subset of the thermodynamical quantites.

Energy and Specific Heat:

Specific Heat (C_V)

Pressure and Entropy:

Entropy (s)

Particle Number Fractions:

Neutron Number Fraction (X_n)

Atomic Mass and Z/A:

The Average Atomic Mass (A)

Gamma and The Sound Speed:


µnp and its Derivatives:


For more information on the Lattimer-Swesty equation of state, see J. Lattimer and D. Swesty, Nuclear Physics A, 535, 1991 or James Lattimer's or Doug Swesty's homepage.