# Equation of state for solar modeling

On this page you can compute thermodynamics for conditions which exist inside the Sun. Different equations of state tables can be used, including SAHA-S equation of state.

## Select output values [help]

Pressure P, dyn/cm^2
Reduced pressure PI = P/(T*rho)
Logarithmic partial derivative dlogP/dlogT (hi_t)
Logarithmic partial derivative dlogP/dlogRHO (hi_rho)
Logarithmic partial derivative dlogP/dlogX (hi_x)
Expansion coefficient Q
Specific internal energy U, erg/g
Specific heat at constant volume Cv
Specific heat at constant pressure Cp
Logarithmic partial derivative dlogU/dlogRHO (ksi_rho)
Sound speed, cm/sec (cs)

If you do not select anything, pressure will still be printed.

## Enter input data [help]

Enter here temperature T, density rho and chemical composition, one set of values per line (multiple lines are allowed). Chemical composition can be entered in four possible ways:

1) separate input fields for X and Z are used, each line contains only T and rho; example:

```2.17e6 0.18
```

2) each line contains T, rho, X and Z; separate input fields for X and Z are ignored; example:

```2.17e6 0.18 0.74 0.018
```

3) each line contains T, rho, X, Z(CNO), Z(Ne), Z(FeSi); separate input fields for X and Z are ignored; example:

```2.17e6 0.18 0.74 0.010 0.002 0.006
```

4) each line contains T, rho, X and 19 components for Z (C, N, O, Ne, Na, Mg, Al, Si, P, S, Cl, Ar, K, Ca, Ti, Cr, Mn, Fe, Ni); separate input fields for X and Z are ignored (this format is not very useful currently)

It is possible but not recommended to mix different numbers of Z components in one job. Input field size does not limit the amount of data entered; you can type or paste thousands of lines (10,000 lines tested with output size over 5MB).

Hydrogen mass fraction X (0.0 - 0.9):

Heavy elements mass fraction Z (0.0 - 0.02):

EOS tables may take up to 20 seconds to load! Please be patient...

Start over with clean input form.