A STREAM SEARCH AMONG 502 TV METEOR ORBITS. AN OBJECTIVE APPROACH
Tadeusz Jan Jopek, Adama Mickiewicza · 1997
In the first part of the paper a short review of the computer meteor stream searching techniques is given. Differ- ent fractions of the stream component obtained amongst radio, photographic and TV data are partially due to the use of dif- ferent methods applied in the stream search. A new objective approachisproposedinordertoobtainthethresholdvalueDc of the orbital similarity corresponding to the probability of chance occurrence of the stream. The 502 Canadian TV data has been usedtotestthisapproach.Itappears,thatthevaluesofDc given bySouthworth&Hawkins(1963),andLindblad(1971b)formu- lae are too high to warrant sufficient reliability of the identified streams. Indeed using these formulae the result is that the prob- ability to obtain by chance at least one stream of 4-5 members goesfrom21%to68%.Theeffectofthethreedifferentdistance functions used to measure the orbital similarity (Southworth & Hawkins (1963), Drummond (1979, 1981), and Jopek 1993) has been investigated. For all functions taking the same 95% reliability level, the number of streams detected is considerably less than in the case of the traditional approach (Jopek 1993a). However, results are different using different distances. Finally, we give the list of the orbits of eight streams identified at the reliability level WM = 95% using the Jopek distance.