Variability is a key property of ultracool dwarfs as it may induce physical noise that limits the accuracy of radial velocities. In this paper we report on our...
Variability monitoring of OB stars during the Mons campaign
We present preliminary results of a 4-month campaign carried out in the framework of the Mons project, where time-resolved Hα observations are used to study the...
Variability of A- and F-stars from Kepler (Uytterhoeven+ 2011)
We compile a database of physical parameters for the sample stars from the literature and new ground-based observations. We analyse the Kepler light curve of...
We have obtained series of images in the near infrared J and Ks bands for seven L-type dwarfs with a duration of 3 to 6 hours. We present results on: 1) the...
Simultaneous UV and optical variations of NGC 5548 suggest a common origin of the continuum flux at both ranges. If the bulk of the UV flux had a black body...
Two broad components in the strongest UV emission lines of NGC 5548 are identified. The components respond differently to continuum changes. A normal broad...
Variability of Solar and Stellar Activity by Two Interacting Hydromagnetic Dynamos
We propose a combination of two dynamos for solar and stellar magnetic activity. A strong-field dynamo operating in the overshoot layer at the base of the...