A new method for an objective, χ2-based spectroscopic analysis of early-type stars. First results from its application to single and binary B- and late O-type stars
Abstract
Context. A precise quantitative spectral analysis, encompassing atmospheric parameter and chemical elemental abundance determination, is time-consuming due to its iterative nature and the multi-parameter space to be explored, especially when done by the naked eye.
Aims: A robust automated fitting technique that is as trustworthy as traditional methods would allow for large samples of stars to be analyzed in a consistent manner in reasonable time.
Methods: We present a semi-automated quantitative spectral analysis technique for early-type stars based on the concept of χ2 minimization. The method's main features are as follows: far less subjectivity than the naked eye, correction for inaccurate continuum normalization, consideration of the whole useful spectral range, and simultaneous sampling of the entire multi-parameter space (effective temperature, surface gravity, microturbulence, macroturbulence, projected rotational velocity, radial velocity, and elemental abundances) to find the global best solution, which is also applicable to composite spectra.
Results: The method is fast, robust, and reliable as seen from formal tests and from a comparison with previous analyses.
Conclusions: Consistent quantitative spectral analyses of large samples of early-type stars can be performed quickly with very high accuracy.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- May 2014
- DOI:
- 10.1051/0004-6361/201323167
- arXiv:
- arXiv:1403.1122
- Bibcode:
- 2014A&A...565A..63I
- Keywords:
-
- binaries: spectroscopic;
- methods: data analysis;
- stars: early-type;
- stars: fundamental parameters;
- stars: general;
- stars: abundances;
- Astrophysics - Solar and Stellar Astrophysics
- E-Print:
- 32 pages, 4 figures, Astronomy and Astrophysics, accepted