Fraunhofer

Introduction

Fraunhofer [1] is a generic stellar abundance determination package that fits observed spectrum with synthetic spectral (from the Synspec package). Fraunhofer uses the Doppler package to get an initial estimate of the main stellar parameters (Teff, logg, [Fe/H]) and radial velocity. It then performs a least-squares fit of the data by searching through parameter space and generated a new Synspec synthetic spectrum (using the synple python wrapper package) at each position.

Description

Fraunhofer has two main modes of operation: 1) a multi-step, iterative fit of the spectrum; or 2) fitting a set of input parameters directly using least-squares. The first option is the default and is the easiest and most automatic way to fit a spectrum. The second option can be used for more hands-on situations.

The default, multi-step approach:

  1. Fit Teff/logg/[Fe/H]/RV using Doppler

  2. Fit Teff/logg/[Fe/H]/RV + vsini with Doppler model

  3. Fit stellar parameters (Teff/logg/[Fe/H]/[alpha/H]), RV and broadening (Vrot/Vmicro)

  4. Fit each element one at a time holding everything else fixed

  5. Fit everything simultaneously

Fraunhofer can be called from python directly or the command-line script hofer can be used.

Examples

hofer

Here are the various input arguments for command-line script hofer:

usage: hofer [-h] [-e ELEM] [-f FPARS] [-i INIT] [--outfile OUTFILE]
             [--figfile FIGFILE] [-d OUTDIR] [-l LIST] [-p] [--vmicro]
             [--vsini] [-r READER] [-v [VERBOSE]]
             files [files ...]

Run Fraunhofer fitting on spectra

positional arguments:
  files                 Spectrum FITS files

optional arguments:
  -h, --help            show this help message and exit
  -e ELEM, --elem ELEM  List of elements to fit
  -f FPARS, --fpars FPARS
                        List of parameteres to fit
  -i INIT, --init INIT  Initial parameters to use
  -o, --outfile OUTFILE Output filename
  --figfile FIGFILE     Figure filename
  -d OUTDIR, --outdir OUTDIR
                        Output directory
  -l LIST, --list LIST  Input list of FITS files
  -p, --plot            Save the plots
  --vmicro              Fit vmicro
  --vsini               Fit vsini
  -r READER, --reader READER
                        The spectral reader to use
  -v [VERBOSE], --verbose [VERBOSE]
                        Verbosity level (0, 1, 2)

Index

Footnotes