Evolution of the compactness of abundant filaments 1, 5, and 6 evaluated with the help of the standard deviation, σ, of the Southworth-Hawkins D-discriminant between the mean orbit of filament and the orbit of each meteor of the filament in given time. While the σ of actual filament that approaches Earth’s orbit is shown in plot a), the σ of selected fixed part of each filament (see end of Sect. 5) is shown in plot b).