| Popis: |
Since 1994, observations of a sample of about 20 Mira Ceti-type and semiregular variables have been carried out in three spectral ranges: radio (H2O maser line λ = 1.35 cm), optical (spectroscopy and UBV photometry) and infrared (JHKLM photometry). Time series of the Hα emission intensity and H2O line flux, covering several periods of the stars, have been obtained. Correlation of the intensity variations of the H2O maser with optical variability in the maser stars RR Aql, U Ori, VX Sgr and others was confirmed. One of the most interesting results is the flare of the H2O maser emission in R Leo, which happened in autumn 1997, 14 months after a flare of the Hα emission. |
