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| Paper: |
New Insights into Stellar Magnetism from the Spectropolarimetry in All Four Stokes Parameters |
| Volume: |
448, 16th Cambridge Workshop on Cool Stars, Stellar Systems, and the Sun |
| Page: |
245 |
| Authors: |
Kochukhov, O.; Snik, F.; Piskunov, N.; Jeffers, S. V.; Keller, C. U.; Makaganiuk, V.; Valenti, J. A.; Johns-Krull, C. M.; Rodenhuis, M.; Stempels, H. C. |
| Abstract: |
Development of high-resolution spectropolarimetry has stimulated a major
progress in our understanding of the magnetism and activity of late-type stars.
During the last decade magnetic fields were discovered and mapped for various
types of active stars using spectropolarimetric methods. However, these
observations and modeling attempts are inherently incomplete since they are
based on the interpretation of the stellar circular polarization alone. Taking
advantage of the recently commissioned HARPS polarimeter, we obtained the
first systematic observations of cool active stars in all four Stokes parameters. Here we
report detection of the magnetically induced linear polarization in the RS CVn
binary HR 1099 and phase-resolved full Stokes vector observations of varepsilon Eri. For the latter star we
measured the field strength with the precision of ∼0.1 G over a complete rotation cycle and reconstructed the
global field topology with the help of magnetic Doppler imaging. Our observations of the inactive solar-like star
α Cen A indicate the absence of the global field stronger than 0.2 G. |
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