Broad-band polarization in molecular spectra
Abstract
The rotational lines of the CN(0,0) red system have been observed to show a strongly asymmetric Zeeman profile. Certain molecules are very susceptible to magnetic perturbation because of the weakness of their spin-rotation coupling; a fairly weak magnetic field can cause a complete Paschen-Back effect. The calculation of transition probabilities incorporating this effect into the Hamiltonian is discussed, and the detailed calculation is then given. The resulting transition probabilities are transformed into synthetic line profiles by using the Unno (1956) model of polarized radiation transfer. The dependence of the net polarized flux on magnetic field and equivalent width is investigated. It is shown that entire band systems may be significantly polarized. Broad-band circular polarization of sunspots may be due, in part, to molecular bands. Analysis of the CH G band indicates a magnetic field of 0.25-0.50 x 10 to the 6th gauss in the white dwarf G99-37, an order of magnitude lower than previous estimates.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- August 1981
- DOI:
- 10.1086/159161
- Bibcode:
- 1981ApJ...248..358I
- Keywords:
-
- Magnetic Stars;
- Molecular Spectra;
- Polarized Radiation;
- Stellar Magnetic Fields;
- Transition Probabilities;
- Zeeman Effect;
- Electron Spin;
- Line Spectra;
- Radiative Transfer;
- Spectrum Analysis;
- Stellar Spectra;
- Astrophysics