Issue |
A&A
Volume 412, Number 2, December III 2003
|
|
---|---|---|
Page(s) | 513 - 527 | |
Section | Stellar atmospheres | |
DOI | https://doi.org/10.1051/0004-6361:20031473 | |
Published online | 28 November 2003 |
The molecular Zeeman effect and diagnostics of solar and stellar magnetic fields
II. Synthetic Stokes profiles in the Zeeman regime
1
Institut für Astronomie, ETH, 8092 Zürich, Switzerland
2
Astronomy Division, PO Box 3000, 90014 University of Oulu, Finland
3
Max-Planck-Institut für Aeronomie, 37191 Katlenburg-Lindau, Germany
Corresponding author: S. V. Berdyugina, sveta@astro.phys.ethz.ch
Received:
28
April
2003
Accepted:
4
September
2003
Recent advances in the computation of the Zeeman splitting of molecular lines have paved the way for their use as diagnostics of solar and stellar magnetic fields. A systematic study of their diagnostic capabilities had not been carried out so far, however. Here we investigate how molecular lines can be used to deduce the magnetic and thermal structure of sunspots, starspots and cool stars. First, we briefly describe the Stokes radiative transfer of Zeeman-split molecular lines. Then, we compute Stokes spectra of TiO, OH, CH and FeH lines and investigate their diagnostic capabilities. We also compare the synthetic profiles with observations. Spectra of TiO, OH and FeH are found to be interesting diagnostics of sunspot magnetic fields. This is also true for cool stars, where, however, the OH Stokes V profiles may require very high S/N data to be reliably employed. Finally we investigate the potential of various molecular bands for high-contrast imaging of the solar surface. The violet CN and CH bands turn out to be most promising for imaging the photosphere, the TiO bands are excellent for imaging sunspot umbrae, while the UV OH band can be used for imaging both the photosphere and sunspots.
Key words: molecular processes / Sun: magnetic fields / stars: magnetic fields / techniques: polarimetric
© ESO, 2003
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