Rapid magnetic flux variability on the flare star CN Leonis

Abstract

We present UVES/VLT observations of the nearby flare star CN Leo covering the Wing-Ford FeH band near 1mu 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~2.2kG. 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.

4 pages, accepted for publication as A&A Letter

References in corpus (3)

• The First Direct Measurements of Magnetic Fields on Very Low-Mass Stars
• The large-scale axisymmetric magnetic topology of avery-low-mass fully-convective star
• Measuring Magnetic Fields in Ultracool Stars and Brown Dwarfs

Cited by in corpus (4)

• Multiwavelength observations of a giant flare on CN Leonis I. The chromosphere as seen in the optical spectra
• A coronal explosion on the flare star CN Leonis
• Spectral type dependent rotational braking and strong magnetic flux in three components of the late-M multiple system LHS 1070
• GTC/CanariCam deep mid-infrared imaging survey of northern stars within 5 pc