111P/Helin–Roman–Crockett
| Discovery | |
|---|---|
| Discovered by |
|
| Discovery site | Palomar Observatory (675) |
| Discovery date | 5 January 1989 |
| Designations | |
| P/1989 A2 | |
| 1988 XIII, 1989b | |
| Orbital characteristics | |
| Epoch | 25 February 2023 (JD 2460000.5) |
| Observation arc | 23.97 years |
| Earliest precovery date | 2 January 1989 |
| Number of observations | 152 |
| Aphelion | 4.595 AU |
| Perihelion | 3.707 AU |
| Semi-major axis | 4.151 AU |
| Eccentricity | 0.1402 |
| Orbital period | 8.457 years |
| Inclination | 4.226° |
| 89.827° | |
| Argument of periapsis | 1.109° |
| Mean anomaly | 72.094° |
| Last perihelion | 16 June 2021 |
| Next perihelion | 9 December 2029 |
| TJupiter | 3.023 |
| Earth MOID | 2.721 AU |
| Jupiter MOID | 0.589 AU |
| Physical characteristics | |
Mean radius | 0.6 km (0.37 mi) |
| Comet total magnitude (M1) | 8.4 |
| Comet nuclear magnitude (M2) | 17.2 |
111P/Helin–Roman–Crockett is an Encke-type comet with an 8.46-year orbit around the Sun. It was co-discovered by Eleanor and Ron Helin, Brian P. Roman and Randy L. Crockett on 5 January 1989 from images obtained about 1-2 days prior.