Letter to the Editor
Apollo asteroid 2005 UD: split nucleus of (3200) Phaethon?
Tokyo Meteor Network, Daisawa 1–27–5, Setagaya-ku, Tokyo 155–0032, Japan e-mail: firstname.lastname@example.org
2 National Astronomical Observatory of Japan, Osawa 2–21–1, Mitaka, Tokyo 181–8588, Japan
3 Institute of Astronomy, National Central University, 300 Jhongda Rd, Jhongli, Taoyuan 32001, Taiwan
4 The Graduate University for Advanced Studies, Osawa 2–21–1, Mitaka, Tokyo 181–8588, Japan
Accepted: 7 March 2006
Context.The recently discovered Apollo asteroid 2005 UD is the most likely candidate for being a large member of the Phaethon-Geminid stream Complex (PGC).
Aims.Detecting more complex members like this should clarify the formation and evolution of the PGC.
Methods.Our backward and forward (±-yr) integration of the Kustaanheimo-Stiefel regularized equation of motion revealed that the orbital evolutions of Apollo asteroids (3200) Phaethon and 2005 UD show a similar profile, time-shifting by ~4600 yr.
Results. Within the PGC, this time shift is rather large against the time-lag of 220 yr for Phaethon-Geminids and ~3900 yr between Phaethon-Sextantids, although much smaller than that of ~ yr between Phaethon-Canis Minorids.
Conclusions.This is a km-order object, hence may be a split nucleus of Phaethon. Besides, the orbital parameters of 2005 UD and the Sextantids are in good agreement along with the time-lag of 100 yr. Therefore, the Sextantid meteor shower seems to be associated more closely with 2005 UD than Phaethon.
© ESO, 2006