A coronal explosion on the flare star CN Leonis
2008 | journal article. A publication with affiliation to the University of Göttingen.
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A coronal explosion on the flare star CN Leonis
Schmitt, J. H. M. M.; Reale, F.; Liefke, C.; Wolter, U.; Fuhrmeister, B.; Reiners, A. & Peres, G. (2008)
Astronomy and Astrophysics, 481(3) pp. 799-805. DOI: https://doi.org/10.1051/0004-6361:20079017
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- Authors
- Schmitt, J. H. M. M.; Reale, F.; Liefke, C.; Wolter, U.; Fuhrmeister, B.; Reiners, Ansgar; Peres, G.
- Abstract
- We present simultaneous high-temporal and high-spectral resolution observations of the nearby flare star CN Leo at optical and soft X-ray wavelengths. During our observing campaign a major flare occurred, raising the star's instantaneous energy output by almost three orders of magnitude. The flare shows the often observed impulsive behavior, with a rapid rise and slow decay in the optical and a broad soft X-ray maximum about 200 seconds after the optical flare peak. In addition to this usually encountered flare phenomenology we find, however, an extremely short (tau(dec) approximate to 2 s) soft X-ray peak, which is very likely of thermal, rather than nonthermal nature and coincides temporally with the optical flare peak. While at hard X-ray energies nonthermal bursts are routinely observed on the Sun at flare onset, thermal soft X-ray bursts on time scales of seconds have never been observed in a solar, nor stellar context. Time-dependent, one-dimensional hydrodynamic modeling of this event requires an extremely short energy deposition time scale tau(dep) of a few seconds to reconcile theory with observations, thus suggesting that we are witnessing the results of a coronal explosion on CN Leo. Thus the flare on CN Leo provides the opportunity to observationally study the physics of the long-sought "micro-flares" thought to be responsible for coronal heating.
- Issue Date
- 2008
- Status
- published
- Publisher
- Edp Sciences S A
- Journal
- Astronomy and Astrophysics
- Organization
- Fakultät für Physik
- ISSN
- 1432-0746