English

Stokes IQUV mapping of $\alpha^2$ CVn & other Ap stars using ESPaDOnS and NARVAL

Solar and Stellar Astrophysics 2015-06-17 v1

Abstract

New spectral line polarisation observations of 7 bright Ap stars have been obtained with the ESPaDOnS and Narval high resolution spectropolarimeters (Silvester et al. 2012). The aim of this data set is produce a series of surface magnetic field and surface chemistry maps for these Ap stars. We present new magnetic maps for the Ap star α2\alpha^2 CVn using these new data and the MDI inversion code INVERS10. α2\alpha^2 CVn is the first Ap star to be observed during two separate epochs using high resolution phase resolved spectropolarimetric IQUVIQUV observations and as such allows us an insight into how stable the surface magnetic structure is over a decade timescale. We show that the new maps give a magnetic field structure consistent with the previous maps obtained by Kochukhov and Wade (2010) from lower quality MuSiCoS spectra taken a decade ago and that the field topology cannot be described by a dipolar or quadrupolar field.

Keywords

Cite

@article{arxiv.1310.5265,
  title  = {Stokes IQUV mapping of $\alpha^2$ CVn & other Ap stars using ESPaDOnS and NARVAL},
  author = {J. Silvester and O. Kochukhov and G. A. Wade},
  journal= {arXiv preprint arXiv:1310.5265},
  year   = {2015}
}

Comments

6 pages, 3 figures. Proceedings of New advances in stellar physics: from microscopic to macroscopic processes (Roscoff 2013)