Magnetic field variations and a giant flare Multiwavelength observations of CN Leo
Abstract
The M5.5 dwarf CN Leo has been observed simultaneously with XMM-Newton and VLT/UVES on three nights in May 2006. Nightly variations of its magnetic field are deduced from FeH lines in the UVES spectra. A giant flare occurred and is covered in total by all instruments. Time-resolved spectroscopy in X-rays traces the development of temperature and emission measure of the coronal flaring plasma. Coronal densities log n_e > 12 are derived during the flare from the O VII triplet. The UVES spectra simultaneously trace the behavior of chromospheric and transition region plasmas. Large increases in the fluxes of chromospheric emission lines are accompanied by a strong enhancement of the continuum level. The Balmer lines show strong broadening and lines of the hydrogen Paschen series are observed in emission during the flare.
- Publication:
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Memorie della Societa Astronomica Italiana
- Pub Date:
- 2007
- Bibcode:
- 2007MmSAI..78..258L
- Keywords:
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- Stars: activity;
- Stars: magnetic fields;
- Stars: flare;
- Stars: coronae;
- Stars: individual: CN Leo;
- X-rays: stars