FUNDPAR

A program for deriving FUNDamental PARameters from equivalent widths

News ! A new version works differentially line-by-line using a reference star (coming soon)

Last update: 20/05/15

Summary:

FUNDPAR is a fortran code which determines fundamental parameters of solar-type stars, using as input Equivalent Widths of Fe I,II lines. The solution should verify 3 conditions in the standard method: ionization equilibrium, excitation equilibrium and independence between metallicity and equivalent widths. We use solar-scaled ATLAS9 model atmospheres with NEWODF opacities, together with the 2009 version of the MOOG program. Parameter files control different details, such as the mixing-length parameter, the overshooting and the damping of the lines. FUNDPAR also derives the uncertainties of the parameters.

Documentation:

The program is described in the paper Saffe (2011).

Some papers that cite our work can be viewed here (courtesy of ADS).

The use of the program is also described in the file install.txt.

Working principle:

We take into account the equilibrium conditions using a χ² function. To evaluate this function we use the following expression: χ² = w₁c₁² + w₂c₂² + w₃c₃² + w₄c₄² , where w₁,...,w₄ are considered weight factors and c₁,...,c₄ are a measure of the different conditions. For instance, c₁ is the slope in the plot of abundance vs. excitation potential. Then, the final solution is equivalent to find the minimum of a 4-dimensional χ² function. For that purpose, we implemented a modified version of the iterative multidimensional Downhill Simplex Method. For more details, see Saffe (2011).

Download:

Installation instructions are detailed in the file install.txt included in the tar file.

The program and its auxiliary files are available for download here: