Magnetic activity in the photosphere and chromosphere of the M dwarf EY Dra is studied and possible correlations between the two are investigated using photometric observations in the V and R bands and optical and near infrared spectroscopy. The longitudinal spot configuration in the photosphere is obtained from the V band photometry, and the chromospheric structures are investigated using variations in the H alpha line profile and observations of the Paschen beta line. The shape of the V band light-curve indicates two active regions on the stellar surface, about 0.4 in phase apart. The spectroscopic observations show enhanced H alpha emission observed close to the phases of the photometrically detected starspots. This could indicate chromospheric plages associated with the photospheric starspots. Some indications of prominence structures are also seen. The chromospheric pressure is limited to logTR < -4 based on the non-detection of emission in the Paschen beta wavelength region.
@article{arxiv.0705.0919,
title = {Photospheric and chromospheric activity on EY Dra},
author = {H. Korhonen and K. Brogaard and K. Holhjem and S. Ramstedt and J. Rantala and C. C. Thoene and K. Vida},
journal= {arXiv preprint arXiv:0705.0919},
year = {2009}
}
Comments
7 pages, 7 figures, accepted for publication in Astronomische Nachrichten (Astronomical Notes)