Seismicity induces ground vertical and horizontal displacements that could affect the image quality obtained by telescopes in a similar fashion than atmospheric turbulence. In this work, we study the effect of local seismicity relative to atmospheric turbulence upon the image quality of astronomical observations at El Teide observatory and Roque de

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Context: Models of flux emergence frequently use a twisted cylindrical loop as the initial starting configuration and ignore the coupling between the radiation field and plasma. In these models, the axis of the original tube never emerges through the photosphere. Without the axis emerging, it is very difficult to form a realistic sunspot. Aims: The

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We present different aspects of the ground-based observational counterpart of the CoRoT satellite mission. We give an overview of the selected asteroseismic targets, the numerous instruments and observatories involved, and the first scientific results.

We present results of the search for variable stars in a sample of Local Group isolated dwarf galaxies, namely LGS3, IC1613, Cetus, and Tucana, based on very deep HST/ACS data. About 900 variables and candidates have been found in total. Among the confirmed variables, we identified about 700 RR Lyrae stars, 60 Cepheids, and 50 eclipsing binaries