Previous abstract Next abstract
A pilot program for the study of stellar coronae through ultraviolet diagnostic lines is in progress with the Goddard High Resolution Spectrograph on the Hubble Space Telescope. An initial result of this program was the detection of the coronal emission line of Fe XXI at 1354 \AA\ in the quiescent spectrum of the dMe star AU Mic (ApJ 421, 800, 1994). The line appeared to be symmetrical, had no measurable radial velocity with respect to the stellar rest frame, and had a width which was consistent with a thermal gas of temperature 10$^7$ K, suggesting very small turbulence within the formation region. In March 1994, we observed the RS CVn binary HR 1099 = HD 22468 (K1 IV + G5 IV ) using instrumental settings identical to those employed with AU Mic, but with the added benefit of the recently-installed HST corrective optics (COSTAR). Each exposure was bracketed by observations of an on-board wavelength calibration lamp. The results of the series of eight 27-minute integrations, obtained at one-orbit intervals, will be presented and compared with the AU Mic spectrum.
Monday program listing