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

• Main Authors: Silvester, J., Kochukhov, O., Wade, G. A.
• Format: Text
• Language: unknown
• Published: arXiv 2013
• Subjects: Solar and Stellar Astrophysics astro-ph.SR; FOS Physical sciences; narval
• Online Access: https://dx.doi.org/10.48550/arxiv.1310.5265; https://arxiv.org/abs/1310.5265

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 $α^2$ CVn using these new data and the MDI inversion code INVERS10. $α^2$ CVn is the first Ap star to be observed during two separate epochs using high resolution phase resolved spectropolarimetric $IQUV$ 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. : 6 pages, 3 figures. Proceedings of New advances in stellar physics: from microscopic to macroscopic processes (Roscoff 2013)