SURFACE INHOMOGENEITIES ON SZ PISCIUM

Ultraviolet and optical data are used to look at surface inhomogeneiti es on the active close binary system SZ Piscium. Lower chromospheric e mission lines such as Mg II h&k, and to a lesser extend the upper chro mospheric/lower transition region lines of O I 1305 Angstrom and C II 1335 Angstrom show a pronounced decrease when the F star is eclipsing the K sub-giant. However, higher temperature lines such as the resonan ce line of C IV 1550 Angstrom do not show any change in flux. This sug gests the presence of a plage with a high contrast at lower temperatur es with a Mg II plage-to-K-star ratio of 5. Alternative explanations a re explored. Monitoring of this system in the optical U-band and the u ltraviolet lines such as C IV 1550 Angstrom, indicates frequent high e nergy (10(35) - 10(36) erg) flares.