The Lorentz Force in Atmospheres of CP Stars: Θ Aur

Details The Lorentz Force in Atmospheres of CP Stars: Θ Aur The Lorentz Force in Atmospheres of CP Stars: Θ Aur

Jun 2005

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2005jkas...38..283v&link_type=abstract

Journal of the Korean Astronomical Society, vol. 38, no. 2, pp. 283-287

Statistics

Computation

5

Stars: Chemically Peculiar, Stars: Magnetic Fields, Stars: Atmospheres

Scientific paper

The slow evolution of global magnetic fields and other dynamical processes in atmospheres of CP magnetic stars lead to the development of induced electric currents in all conductive atmospheric layers. The Lorentz force, which results from the interaction between a magnetic field and the induced currents, may modify the atmospheric structure and provide insight into the formation and evolution of stellar magnetic fields. This modification of the pressure-temperature structure influences the formation of absorption spectral features producing characteristic rotational variability of some spectral lines, especially the Balmer lines (Valyavin et al., 2004 and references therein). In order to study these theoretical predictions we began systematic spectroscopic survey of Balmer line variability in spectra of brightest CP magnetic stars. Here we present the first results of the program. A0p star Θ Aur revealed significant variability of the Balmer profiles during the star's rotation. Character of this variablity corresponds to that classified by Kroll (1989) as a result of an impact of significant Lorentz force. From the obtained data we estimate that amplitudes of the variation at H_α, H_β, H_γ and H_δ profiles reach up to 2.4% during full rotation cycle of the star. Using computation of our model atmospheres (Valyavin et al., 2004) we interpret these data within the framework of the simplest model of the evolution of global magnetic fields in chemically peculiar stars. Assuming that the field is represented by a dipole, we estimate the characteristic e.m.f. induced by the field decay electric current (and the Lorentz force as the result) on the order of E ˜ 10-11 cgs units, which may indicate very fast ( << 1010 years) evolution rate of the field. This result strongly contradicts the theoretical point of view that global stellar magnetic fields of CP stars are fossil and their the characteristic decay time of about 1010 yr. Alternatively, we briefly discuss concurring effects (like the ambipolar diffusion) which may also lead to significant atmospheric currents producing the observable Lorentz force.

Affiliated with

Also associated with

No associations

Rating

The Lorentz Force in Atmospheres of CP Stars: Θ Aur does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with The Lorentz Force in Atmospheres of CP Stars: Θ Aur, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The Lorentz Force in Atmospheres of CP Stars: Θ Aur will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1399508