103P/Hartley
Comet Hartley 2, designated as 103P/Hartley by the Minor Planet Center, is a small periodic comet with an orbital period of 6.48 years. It was discovered by Malcolm Hartley in 1986 at the Schmidt Telescope Unit, Siding Spring Observatory, Australia. Its diameter is estimated to be 1.2 to 1.6 kilometres (0.75 to 0.99 mi).
Photograph from close approach by EPOXI mission | |
| Discovery | |
|---|---|
| Discovered by | Malcolm Hartley |
| Discovery date | 15 March 1986 |
| Designations | |
Alternative designations | 103P/1986 E2 |
| Orbital characteristics | |
| Epoch | 2023-10-23 |
| Aphelion | 5.89 AU (Q) |
| Perihelion | 1.06 AU (q) |
| Semi-major axis | 3.48 AU (a) |
| Eccentricity | 0.694 |
| Orbital period | 6.48 years |
| Inclination | 13.61° |
| Last perihelion | 20 April 2017 28 October 2010 |
| Next perihelion | 2023-Oct-12 2030-Apr-05 |
| Earth MOID | 0.072 AU (10,800,000 km) |
Hartley 2 was the target of a flyby of the Deep Impact spacecraft, as part of the EPOXI mission, on 4 November 2010, which was able to approach within 700 kilometers (430 mi) of Hartley 2 as part of its extended mission. As of November 2010 Hartley 2 is the smallest comet which has been visited. It is the fifth comet visited by spacecraft, and the second comet visited by the Deep Impact spacecraft, which first visited comet Tempel 1 on 4 July 2005.