| Discovery | |
|---|---|
| Discovered by | A. E. Thatcher |
| Discovery date | April 5, 1861 |
| Designations | |
| Alternative designations | 1861 I |
| Orbital characteristics | |
| Observation arc | 149 days |
| Number of observations | 187 |
| Orbit type | Long period comet |
| Aphelion | 112 AU (beyond Eris) |
| Perihelion | 0.921 AU (1861) 0.917 AU (2283) |
| Semi-major axis | 56.3 AU |
| Eccentricity | 0.983 |
| Orbital period | 422 yr (barycentric) |
| Inclination | 79.77° |
| Last perihelion | 1861-Jun-03 |
| Next perihelion | 2283 ±5 |
Comet C/1861 G1 (Thatcher) is a long-period comet with roughly a 422-year orbit that is expected to return around 2283. It was discovered by A. E. Thatcher. It is responsible for the April Lyrid meteor shower. Carl Wilhelm Baeker also independently found this comet. The comet passed about 0.335 AU (50.1 million km; 31.1 million mi) from the Earth on 5 May 1861 and last came to perihelion (closest approach to the Sun) on 3 June 1861.
C/1861 G1 is listed as a long-period "non-periodic comet" because it has not yet been observed at two perihelion passages. When it is seen to come back around 2283, it should receive the P/ designation.
The comet is the parent body of the April Lyrids meteor shower.
See also
- C/1861 J1 – Great comet of 1861
- 153P/Ikeya–Zhang – periodic comet with a 366-year orbit
References
- Horizons output. "Barycentric Osculating Orbital Elements for Thatcher (C/1861 G1) at epoch 1900". Retrieved 2023-08-26. (Solution using the Solar System's barycenter (Sun+Jupiter). Select Ephemeris Type:Elements and Center:@0)
(PR= 1.54E+05 / 365.25 = 422 years) - ^ Horizons output. "2283 Perihelion for Comet C/1861 G1 (Thatcher)". Retrieved 2020-08-07. (Observer Location:@sun Perihelion occurs when deldot flips from negative to positive)
- ^ "JPL Small-Body Database Browser: C/1861 G1 (Thatcher)". Jet Propulsion Laboratory. Retrieved 2012-04-21.
- Arter, T. R.; Williams, I. P. (1997). "The mean orbit of the April Lyrids". Monthly Notices of the Royal Astronomical Society. 289 (3): 721–728. Bibcode:1997MNRAS.289..721A. doi:10.1093/mnras/289.3.721.
External links
- Thatcher at the JPL Small-Body Database
.png)
