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The periodic variations of a white-light flare observed with ULTRACAM
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Mathioudakis, M., Bloomfield, D. S., Jess, D. B., Dhillon, V. S. and Marsh, T. R. (2006) The periodic variations of a white-light flare observed with ULTRACAM. Astronomy & Astrophysics, Vol.456 (No.1). pp. 323-327. doi:10.1051/0004-6361:20054752 ISSN 0004-6361.
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Official URL: http://dx.doi.org/10.1051/0004-6361:20054752
Abstract
High time resolution observations of a white-light flare on the active star EQ PegB show evidence of intensity variations with a period of ≈10 s. The period drifts to longer values during the decay phase of the flare. If the oscillation is interpreted as an impulsively-excited,
standing-acoustic wave in a flare loop, the period implies a loop length of ≈3.4 Mm and ≈6.8 Mm for the case of the fundamental mode and the second harmonic, respectively. However, the small loop lengths imply a very high modulation depth making the acoustic interpretation unlikely. A more realistic interpretation may be that of a fast-MHD wave, with the modulation of the emission being
due to the magnetic field. Alternatively, the variations could be due to a series of reconnection events. The periodic signature may then arise as a result of the lateral separation of individual flare loops or current sheets with oscillatory dynamics (i.e., periodic reconnection).
Item Type: | Journal Article | ||||
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Subjects: | Q Science > QB Astronomy | ||||
Divisions: | Faculty of Science, Engineering and Medicine > Science > Physics | ||||
Library of Congress Subject Headings (LCSH): | Flare stars, Stars -- Corona -- Magnetic fields, Stellar oscillations | ||||
Journal or Publication Title: | Astronomy & Astrophysics | ||||
Publisher: | EDP Sciences | ||||
ISSN: | 0004-6361 | ||||
Official Date: | September 2006 | ||||
Dates: |
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Volume: | Vol.456 | ||||
Number: | No.1 | ||||
Page Range: | pp. 323-327 | ||||
DOI: | 10.1051/0004-6361:20054752 | ||||
Status: | Peer Reviewed | ||||
Access rights to Published version: | Open Access (Creative Commons) | ||||
Funder: | Particle Physics and Astronomy Research Council (Great Britain) (PPARC) | ||||
Grant number: | PPA/G/S/2002/00092 (PPARC) |
Data sourced from Thomson Reuters' Web of Knowledge
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