21P/Giacobini–Zinner
Comet Giacobini–Zinner photographed from Moscow, Russia on 9 September 2018. | |
| Discovery | |
|---|---|
| Discovered by | Michel Giacobini Ernst Zinner |
| Discovery date | 20 December 1900 23 October 1913 |
| Designations | |
| P/1900 Y1 P/1913 U1 | |
| 1900 III; 1913 V; 1926 VI; 1933 III; 1940 I; 1946 V; 1959 VIII; 1966 I; 1972 VI; 1979 III; 1985 XIII; 1992 IX | |
| Orbital characteristics | |
| Epoch | 26 March 2025 (JD 2460760.5) |
| Observation arc | 4,922 days (13.48 years) |
| Number of observations | 7,387 |
| Aphelion | 5.97 AU |
| Perihelion | 1.009 AU |
| Semi-major axis | 3.49 AU |
| Eccentricity | 0.7111 |
| Orbital period | 6.525 years |
| Inclination | 32.05° |
| 195.3° | |
| Argument of periapsis | 172.9° |
| Last perihelion | 25 March 2025 |
| Next perihelion | 30 August 2031 |
| TJupiter | 2.465 |
| Earth MOID | 0.018 AU |
| Jupiter MOID | 0.248 AU |
| Physical characteristics | |
| Dimensions | 2.0 km (1.2 mi) |
| 7.39±0.01 hours | |
| Comet total magnitude (M1) | 13.2 |
| Perihelion distance at different epochs | |||||||
| Epoch | Perihelion (AU) | ||||||
|---|---|---|---|---|---|---|---|
| 1894 | 1.23 | ||||||
| 1900 | 0.93 | ||||||
| 1985 | 1.03 | ||||||
| 2031 | 1.07 | ||||||
| 2078 | 0.97 | ||||||
Comet Giacobini–Zinner (officially designated as 21P/Giacobini–Zinner) is a periodic comet in the Solar System. It was discovered by Michel Giacobini, who observed it in the constellation of Aquarius on 20 December 1900. It was recovered two orbits later by Ernst Zinner, while he was observing variable stars near Beta Scuti on 23 October 1913.
It will pass 0.364 AU (54.5 million km) from Jupiter on 14 February 2029, then come to perihelion on 30 August 2031 at 1.07 AU from the Sun, and then pass 0.554 AU (82.9 million km) from Earth on 3 September 2031.