Документ взят из кэша поисковой машины. Адрес оригинального документа : http://star.arm.ac.uk/~ambn/abstract175.html Дата изменения: Fri May 31 18:25:33 1996 Дата индексирования: Tue Oct 2 00:09:05 2012 Кодировка: Поисковые слова: annular solar eclipse

Ultraviolet and optical data are used to look at surface inhomogeneities on the active close binary system SZ Piscium. Lower chromospheric emission lines such as Mg II h\&k, and to the lesser extend the upper chromospheric/lower transition region lines of O I 1305 $\AA$ and C II 1335$\AA$ show a pronounced decrease when the F star is eclipsing the K sub-giant. However, higher temperature lines such as the resonance line of C IV 1559$\AA$ do not show any change in flux. This suggests the presence of a plage with a high contrast at lower temperatures with a Mg II plage-to-K-star ratio of 5. Alternative explanations are explored. Monitoring of this system in the optical U-band and the ultraviolet lines such as C IV 1550 $\AA$, indicates frequent high energy (10$^{35}$ - 10$^{36}$ erg) flares.
Key words: rotational modulation - magnetic activity - plages - flares