C/1985 R1 (Hartley–Good)
| Discovery | |
|---|---|
| Discovered by | Malcolm Hartley A. R. Good |
| Discovery site | Siding Spring Observatory |
| Discovery date | 11 September 1985 |
| Designations | |
| 1985 XVII, 1985l | |
| Orbital characteristics | |
| Epoch | 2 November 1985 (JD 2446371.5) |
| Observation arc | 187 days |
| Earliest precovery date | 21 August 1985 |
| Number of observations | 165 |
| Aphelion | ~12,300 AU |
| Perihelion | 0.695 AU |
| Semi-major axis | ~6,160 AU |
| Eccentricity | 0.99989 |
| Orbital period | ~480,000 years |
| Inclination | 79.929° |
| 358.39° | |
| Argument of periapsis | 87.033° |
| Mean anomaly | 359.99° |
| Last perihelion | 9 December 1985 |
| TJupiter | 0.182 |
| Earth MOID | 0.221 AU |
| Jupiter MOID | 2.966 AU |
| Physical characteristics | |
Mean radius | 0.88±0.05 km |
| Mass | 1.10×1012 kg |
Mean density | 490±70 kg/m3 |
| Comet total magnitude (M1) | 8.3 |
| 6.3–6.6 (1985 apparition) | |
Comet Hartley–Good, formally designated as C/1985 R1, is a non-periodic comet that was observed from September 1985 to March 1986. It is the sixth comet discovered overall by Malcolm Hartley and the only one for A. R. Good.