The correlation between the magnitude of the proper motion and the mean frequency of flares for flare stars in the Pleiades cluster region is discussed. The magority of them are physical members of this star cluster. It is shown that there exist probably two groups of flare stars which differ each other by their parameters, in particular by the magnitude of proper motions. A possible explanation of this phenomenon is suggested.

Using the actual observational data on photometric and spectral stellar activity in the region of central area of the Taurus Dark Clouds complex, the question of flare activity of the stars and its connection with another kinds of activities is considered. The comparison of stellar flares in this region with that of in other associations and clusters (especially, Orion and Pleiades) is made and the youth of the group in Taurus is shown. The detection of flaring variables (including stars with T Tauri-type features) in Taurus region is the evidence in favour of evolutionary connection of these stages.

Statistically relevant samples of flare stars in stellar aggregates can be used to specify the stellar mass-age-activity-relation when the ages of the aggregates are known from independent investigations. Associations and clusters of the southern sky are currently surveyed with the GPO astrograph of the European Southern Observatory. The plates are digitized with the PDS 2020 GMplus microdensitometer and the data are reduced automatically at the Astronomical Institute of Muenster University. The programme package “FLARE” is described. First results from the Orion association are presented.

Spectral observations of 6 flare stars in the Pleiades cluster are carried out which occupy different positions on the Hertzsprung-Russell diagram relative to the main sequence: above and below it. The spectral indices which are sensible to luminosity or temperature of the star photosphere are determined. Significant differences between indices of the stars belongings to these two groups are not detected.

Spectroscopic observations of the flare stars HM1 and HM2 (V667 CrA) in the direction of the R Coronae Austrinae aggregate are presented. The respective spectral classes are dM1e and dM6e. Both stars are at the distance 40 pc, much closer than the R CrA association.

A Catalog of flare stars of the region around the Orion Trapezium is compiled. The results of photographic patrol observations of flare stars in this region carried out at the observatories: Abastumani, Asiago, Byurakan, La-Silla, Rojen, Tonantzintla and Uppsala, up to 1986 year are used. The Catalog contains infomation for 491 flare stars and their 654 flares. It is compared with the Catalog of flare stars in the Pleiades region.

A catalogue of known flare stars in the region of the emission nebulae NGC 7000 - IC 5068-70 and IC 1318 a,b,c in Cygnus is presented. The UBV magnitudes and spectral types, as far as available, for 96 flare stars and their 144 flares were collected. Patrol observations from the Asiago, Byurakan, Konkoly, Rozhen and Tonantzintla observatories, covering a total of 1500 hours effective observing time were used.

The study of slow flares in star clusters, associations and Solar Vicinity is carried out. The dependances of flare amplitude from the inverse velocity of flare increasing time in U, B, V bands are obtained. It is shown, that strong flares frequently take place in deep layers of stellar photosphere.

The problem of the statistical prediction of flare activity of a group of flare stars in stellar aggregates is considered.

A new set of isochrones derived from overshooting evolutionary models, allows one to give a homogeneous age determination for open clusters with solar chemical composition and in a range of age 4 107 ÷ 1.5 109 yr. In this context is derived an empirical new age calibration - absolute magnitude of the supposed brightest flare star in a cluster versus log age -. The evolutionary implication in finding or not finding flare stars in candidate open clusters is also examined.

The problem of flare activity frequency among red dwarf stars is discussed. The observational data on stars in Orion, Pleiades and solar vicinity are used. It is shown, that relative number of flare stars among all red dwarf stars in the considered samples is increasing towards the lower luminosity stars. The flare stars are found in the considered samples begining with a definite luminosity, this limiting luminosity being decreased with the aging of the system which includes flare stars. A possible explanation of the observed phenomenon is given.

The radio emission from dMe flare stars is discussed using Very Large Array and Arecibo observations as examples. Active flare stars emit weak, unpolarized, quiescent radio radiation that may be always present. Although thermal bremsstrahlung and/or thermal gyroresonance radiation account for the slowly-varying, quiescent radio radiation of solar active regions, these processes cannot account for the long-wavelength quiescent radiation observed from nearby dMe flare stars. It has been attributed to nonthermal gyrosynchrotron radiation, but some as yet unexplained mechanism must be continually producing the energetic electrons. Long-duration (hours), narrow-band (Δv/v < 0.1) radiation is also emitted from some nearby dMe stars at 20 cm wavelength. Such radiation may be attributed to coherent plasma radiation or to coherent electron-cyclotron masers. Impulsive stellar flares exhibit rapid variations (< 100 msec) that require radio sources that are smaller than the star in size, and high brightness temperatures TB > 1015 K that are also explained by coherent radiation processes. Quasi-periodic temporal fluctuations suggest pulsations during some radio flares. Evidence for frequency structure and positive or negative frequency drifts during radio flares from dMe stars is also presented.

Several nearby flare stars have been observed with spectrometers on various large telescopes. The experience of several attempts to record stellar radio flares is summarized including an event on AD Leo that was detected by three widely separated large telescopes. The event is analogue to solar decimetric pulsations. An interpretation in terms of coherent cyclotron emission (maser) is given and the source size, exciter drift velocity and source magnetic field are estimated.

The first at the world Radio-Optical Telescope ROT-32/54/2, 6 was mounted on the southern slope of Mount Aragats in Armenia at 1700 m above sea level. The Large Antenna of ROT with the unmovable hemisperical main mirror of 54 m in diameter and movable small correcting mirror is the extremely accurate and shortwave (down to 1 mm). Using aperture is 32m. The diameter of the Optical Telescope is 2.6 m. General view of ROT is shown in Fig.1.

A brief summary is given of a comprehensive analysis of EXOSAT observations of solar neighbourhood flare stars. Special attention is devoted to the discussion of quiescent X-ray emission and time variability.

Integrated soft X-ray (8-12A) fluxes for solar flares have been scaled to the equivalent EXOSAT fluxes using spectra obtained from a variety of rocket-based experiments. The data show good agreement with the soft X-ray - Hγ correlation established by Butler et al. (1988) for stellar flares and confirm the basic similarity, in this respect, of flares on the Sun to those on dMe stars.

We have examined each of the 172 EINSTEIN X–ray sources in Orion for both short (100–10,000 seconds) and long (1 day to 2 years) timescale variability. No strong flares were seen in 75,000 total seconds of observations. We compare the Orion variability results with those from the ρ Oph star–forming region, solar X–ray flares and dMe U–band flares.

This symposium is dedicated to the results of studies of flare stars. The necessity of the detailed analysis of observational data on flare stars follows from the very simple fact, that until now the theory has not found for the answer to the question: why the young stars of low luminosity are flaring.

For many years we have monitored the variability of some bright T Tauri stars with the 0.6 m “Perkin telescope” at Van Vleck Observatory. Collaborators in this endeavor have included several astronomers at the Crimea Astrophysical Observatory, at Capidomonte Observatory, at the U.S. Naval Observatory, and even some sophisticated amateurs.

T Tauri-type stars are characterized by the fast irregular variability. It is possible to select several components in brightness variations: slow components with timescales of years and fast ones with timescales of days and tens of days. Besides, up to 1 mag flares in the ultraviolet part of the spectrum occur during some nights. The overall change of the brightness may reach 2-3 mag.