The periodic variations of a white-light flare observed with ULTRACAM
Data(s) |
01/09/2006
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Resumo |
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). |
Identificador |
http://dx.doi.org/10.1051/0004-6361:20054752 http://www.scopus.com/inward/record.url?scp=33748685205&partnerID=8YFLogxK |
Idioma(s) |
eng |
Direitos |
info:eu-repo/semantics/restrictedAccess |
Fonte |
Mathioudakis , M , Bloomfield , S , Jess , D , Dhillon , V S & Marsh , T R 2006 , ' The periodic variations of a white-light flare observed with ULTRACAM ' Astronomy and Astrophysics , vol 456 , no. 1 , pp. 323-327 . DOI: 10.1051/0004-6361:20054752 |
Palavras-Chave | #waves #stars: activity #stars: atmospheres #stars: flare #stars: individual #EQ Pegasi #/dk/atira/pure/subjectarea/asjc/1900/1912 #Space and Planetary Science |
Tipo |
article |