Comet West–Hartley is a periodic comet roughly 4 km in diameter with a 7.67-year orbit around the Sun. The current orbit does not bring it closer than about 1.2 AU (180 million km) from Earth. It will next come to perihelion on 21 September 2026, when the comet will have a solar elongation of 22 degrees. It will come to opposition on 1 May 2027.
Physical characteristics The first attempts to measure the effective radius of its nucleus in 2000 were not successful due to too much scatter data in light curves obtained to provide reliable estimates. Recent attempts to measure the comet's light curves between 2004 and 2015 revealed that the nucleus is about 2.18 km (1.35 mi) in radius, rotating once every 3.7 hours.
References
External links 123P/West–Hartley at the JPL Small-Body Database 123P/West–Hartley at Gary W. Kronk's Cometography 123P/West–Hartley at Gideon van Buitenen's website 123P/West–Hartley at Seiichi Yoshida's website 123P/West–Hartley on 2026 Apr 06 at apmag 17.6