ABUNDANCE

The program ABUNDANCE can be used to calculate elemental abundances from equivalent widths. The necessary inputs are a stellar atmosphere model for the star being analyzed, the atomic and molecular datafile stdatom.dat and a linelist file with equivalent widths. The linelist file has the following format:

6127.895   26.0   33413   49727   -1.368  1.000 99 39.6 KFE
6165.361   26.0   33413   49628   -1.45   1.000 21 37.4 NIST
6232.635   26.0   29469   45509   -1.100  1.300 99 72.6 KFE

This linelist file has the same format as the linelist file for SPECTRUM except for one extra column - the penultimate column - which contains the equivalent width of the line in units of mÅ. Note that the seventh column contains the transition type; all the transition types valid for SPECTRUM are also valid here (with the exception of AI), including the AO and the GA types. If the AO type is used, then the next column is used for the $\sigma$ and $\alpha$ parameters, in the packed format as explained in the documentation for SPECTRUM; the equivalent width will still be entered in the next-to-last column. Likewise for the GA transition type - see § .

Only the ``t'' switch may be used with ABUNDANCE (see § ). This implies that isotopes are not supported. Likewise, while hyperfine components may technically be analyzed with ABUNDANCE it would be necessary to measure equivalent widths for each hyperfine component. Abundances based on lines that show significant isotope splitting or broad profiles due to hyperfine structure are best analyzed with full spectral synthesis.

The output of ABUNDANCE has the following format:

6127.895   26.0  1.08   -4.581    7.459  -0.041
6165.361   26.0  1.08   -4.550    7.490  -0.010
6232.635   26.0  1.08   -4.581    7.460  -0.041

The meaning of the first and second columns are obvious, the third column is the microturbulent velocity (in km/s) input into ABUNDANCE (it prompts the user for this quantity). The fourth column gives the abundance on the scale native to SPECTRUM (see § ), and the fifth on the normal scale, in which the logarithmic abundance of hydrogen is equal to 12.0. The final column is the abundance relative to the unscaled abundances in stdatom.dat; since the stdatom.dat abundances are solar abundances, the final column gives the quantity [X/H] where X is the species in question. Note that if you are using a custom atomic and molecular data file, this may not necessarily be the case.