Orbital Characteristics of Comets Passing through the 1:1 Commensurability with Jupiter

Abstract

When, in consequence of a close approach, a comet of the Jupiter group changes its osculating semimajor axis from a > 1 to a < 1 (a’ = 1 for Jupiter’s orbit), or vice versa, then the normal case is that of an abrupt change from one side of Jupiter’s orbit to the other one. Under special conditions, however, temporary capture into satellite or ‘Trojan’ status is possible. P/Slaughter-Burnham, the first known comet in temporary 1:1 resonance with Jupiter, sheds some light on the requirements for Trojan captures. In consideration of the recent finding that the Trojan ‘cloud’ around L ₄ contains probably as many as 700 Trojans brighter than magnitude 20.9, it is suggested that at least some comets of the Jupiter group may have originated among these accumulations around L ₄ and L ₅.