P. B. Byrne

The extraordinary flare/by Dra star HDE319139

HDE319139 was noted originally as a strong Balmer emission star by Cannon and Mayall (1938) on objective prism plates. Later Merrill and Burwell (1950) and Bidleman (1954) remarked on the unusual strength of its Ha emission. Busko and Torres (]976, 1978) recorded U-band flares and BY Draconis variations, the latter with a period of 1.70 days, since revised to 2.45 days (Tortes, private communication). They also remarked on a 0.15 mag excess in (U-B) over that for a normal K5 star (its HD classification) which showed a large scatter about the mean. Here we make a preliminary report on optical photometry and spectroscopy made during 1984.

Flare activity and by-Draconis type variability on the late-type dMe star gliese 867B

We report on an analysis of flaring and BY-Draconis type variability on the Balmer emission line star, Gliese 867B. The time-averaged flare energy in the Johnson 1-band is similar to that measured in 1977 and 1978. A variation of 0.15 magnitudes was observed in the V-band with a period l.95 days.

Optical Photometry of Flares and Flare Statistics

This review discusses optical observations of flares and the results gleaned from these. Excellent reviews of flare activity have been published in the past and one might mention in particular Kunkel (1975), Gershberg (1978) and Gurzadyan (1980). In general these have been more broadly based than the present review incorporating other aspects of flare stars e.g. BY Dra variability, spectroscopic observations, etc. Since these other aspects of flare star behaviour are being covered elsewhere in this volume we will confine ourselves exclusively to optical photometry of the flare phenomenon itself. We will also confine ourselves to the solar-neighbourhood flare stars (i.e. the UV Ceti stars) since other contributors will discuss the T-Tauri, RS CVn, BY Dra and other flaring objects.