Analysis of the Lyrids’ meteor stream structure for long timeslots

Lyrids’ structural parameters (luminosity function parameter r of meteors distribution magnitudes, the S parameter distribution of meteoroids in the mass flow, zenithal hour number (ZHR)) are determined by visual observations made in the 1900–2007 interval. The minimal value of S is equal to 1.54 ± 0.02 and corresponds to the Sun longitude 32.19° ± 0.04°. Lyrids’ activity profiles as ZHR depending on the Sun longitude (L) were constructed for studying the flow activity. ZHR averaging for the individual values was held according the observation in 1900–1963, 1900–2000, 2001–2007 and 1900–2007. The peak position for all groups is the same within the error and equal to 32.326° ± 0.107. Two periods of Lyrids activity were revealed: a period which is close to 60 years; and s period of about 10–12 years.