THE PARENT OF THE QUADRANTID METEOROID STREAM

The Quadrantid meteor shower is one of the major showers that produces reliable displays every January. However, it is unique amongst the ma jor showers in still not having its parent uniquely identified. One of the reasons for this may be because the stream, and presumably the pa rent, lies in a region of the Solar system where near-resonant motion with Jupiter, coupled with potential close encounters, is possible. Su ch a combination can lead to a rapid dynamical evolution of an orbit. In particular, it may be possible that the orbit of the parent both sa tisfies the condition for a close encounter and is in resonant motion, while most of the meteoroids cannot satisfy both conditions. This res ults in the parent evolving away from the bulk of the stream. To date, two suggestions have been made regarding possible parents for the Qua drantid stream, these being Comet 1491 I and Comet 96P/Machholz, The a rgument in favour of the first named being the parent is because of th e general similarity between the orbits around 1491. The argument for comet 96P/Machholz being the parent is based on the similarity in orbi tal evolution coupled with a similarity in orbits phase-shifted by 200 0 yr. In this paper we suggest that on both counts asteroid 5496 (1973 NA) is more similar to the Quadrantids, and that even if 5496 is not the actual parent in the strict sense that meteoroids are currently be ing ejected, it is either likely to be a fragment of the parent or the dormant remains of the parent.