Документ взят из кэша поисковой машины. Адрес оригинального документа : http://star.arm.ac.uk/~ambn/abstract207.ps Дата изменения: Thu Aug 15 19:45:51 1996 Дата индексирования: Mon Oct 1 23:35:48 2012 Кодировка: Поисковые слова: ion drive

Flare energetics: Analysis of a large flare on YZ
CMi observed simultaneously in the ultraviolet,
optical and radio
G.H.J. van den Oord, J.G. Doyle, M. Rodono, D.E. Gary,
G.W. Henry, P.B. Byrne, J.J. Linsky, B.M. Haisch, I. Pagano
and G. Leto
A&A, Nov. 1995
The results of coordinated observations of the dMe star YZ CMi at optical, UV
and radio wavelengths during 3 ­ 7 February 1983 are presented. YZ CMi showed
repeated optical flaring with the largest flare having a magnitude of 3.8 in the U­
band. This flare coincided with an IUE exposure which permits a comparison
of the emission measure curves of YZ CMi in its flaring and quiescent state.
During the flare a downward shift of the transition zone is oberved while the
radiative losses in the range 10 4 ­ 10 7 K strongly increase. The optical flare is
accompanied with a radio flare at 6 cm, while at 20 cm no emission is detected.
The flare is interpreted in terms of optically thick synchrotron emission. We
present a combined interpretation of the optical/radio flare and show that the
flare can be interpreted within the context of solar two­ribbon/white­light flares.
Special attention is paid to the bombardment of dMe atmospheres by particle
beams. We show that the characteristic temperature of the heated atmosphere
is almost independent of the beam flux and lies within the range of solar white­
light flare temperatures. We also show that it is unlikely that stellar flares emit
black­body spectra. The fraction of accelerated particles, as follows from our
combined optical/radio interpretation is in good agreement with the fraction
determined by two­ribbon flare connection models.
1