A STREAM SEARCH AMONG 502 TV METEOR ORBITS - AN OBJECTIVE APPROACH

In the first part of the paper a short review of the computer meteor s tream searching techniques is given. Different fractions of the stream component obtained amongst radio, photographic and TV data are partia lly due to the use of different methods applied in the stream search. A new objective approach is proposed in order to obtain the threshold value D-c of the orbital similarity corresponding to the probability o f chance occurrence of the stream. The 502 Canadian TV data has been u sed to test this approach. It appears, that the values of D-c given by Southworth & Hawkins (1963), and Lindblad (1971b) formulae are too hi gh to warrant sufficient reliability of the identified streams. Indeed using these formulae the result is that the probability to obtain by chance at least one stream of 4-5 members goes from 21% to 68%. The ef fect of the three different distance functions used to measure the orb ital similarity (Southworth & Hawkins (1963), Drummond (1979, 1981), a nd Jopek 1993) has been investigated. For all functions taking the sam e 95% reliability level, the number of streams detected is considerabl y less than in the case of the traditional approach (Jopek 1993a). How ever, results are different using different distances. Finally, we giv e the list of the orbits of eight streams identified at the reliabilit y level W-M = 95% using the Jopek distance.