A&A 466, L13-L16 (2007)
Rapid magnetic flux variability on the flare star CN LeonisA. Reiners1, 2, J. H. M. M. Schmitt1, and C. Liefke1
1 Hamburger Sternwarte, Gojenbergsweg 112, 21029 Hamburg, Germany
2 Universität Göttingen, Institut für Astrophysik, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
(Received 15 January 2007 / Accepted 28 February 2007)
We present UVES/VLT observations of the nearby flare star CN Leo covering the Wing-Ford FeH band near 1 m with high spectral resolution. Some of the FeH absorption lines in this band are magnetically sensitive and allow a measurement of the mean magnetic flux on CN Leo. Our observations, covering three nights separated by 48 hours each, allow a clear detection of a mean magnetic field of Bf 2.2 kG. The differential flux measurements show a night-to-night variability with extremely high significance. Finally, our data strongly suggest magnetic flux variability on time scales as low as 6 hours in line with chromospheric variability.
Key words: stars: activity -- stars: late-type -- stars: magnetic fields -- stars: individual: CN Leo
© ESO 2007