10P/Tempel
Jupiter-family comet
From Wikipedia, the free encyclopedia
10P/Tempel, also known as Tempel 2, is a Jupiter-family comet with a 5.36-year orbit around the Sun. It was discovered on 4 July 1873 by Wilhelm Tempel.[11] At the perihelion passage on 2 August 2026 the solar elongation is calculated at 164 degrees, with apparent magnitude approximately 8,[4] with closest approach to Earth on 3 August 2026 at a distance of 0.414 AU (61.9 million km).[2]
| Date & time of closest approach |
Earth distance (AU) |
Sun distance (AU) |
Velocity wrt Earth (km/s) |
Velocity wrt Sun (km/s) |
Uncertainty region (3-sigma) |
Reference |
|---|---|---|---|---|---|---|
| 2026-Aug-03 20:56 | 0.414 AU (61.9 million km; 38.5 million mi) | 1.42 AU (212 million km; 132 million mi) | 6.5 | 31.0 | ± 200 km | Horizons |
- Tempel 2
- 1873 II, 1878 III, 1894 III
- 1899 IV, 1904 III, 1915 I
- 1920 II, 1925 IV, 1930 VII
- 1946 III, 1951 VIII, 1957 II
- 1962 VI, 1967 X, 1972 X
- 1978 V, 1983 X, 1988 XIV
- 1994 VII
Comet Tempel 2 photographed by H. M. Jeffers from the Lick Observatory in 1946[1] | |
| Discovery | |
|---|---|
| Discovered by | Wilhelm Tempel |
| Discovery date | 4 July 1873 |
| Designations | |
| P/1873 N1, P/1878 O1 | |
| |
| Orbital characteristics[2][3] | |
| Epoch | 5 May 2025 (JD 2460800.5) |
| Observation arc | 130.78 years |
| Number of observations | 5,700 |
| Aphelion | 4.710 AU |
| Perihelion | 1.417 AU |
| Semi-major axis | 3.064 AU |
| Eccentricity | 0.53738 |
| Orbital period | 5.362 years |
| Inclination | 12.027° |
| 117.80° | |
| Argument of periapsis | 195.50° |
| Mean anomaly | 276.53° |
| Last perihelion | 24 March 2021 |
| Next perihelion | 2 August 2026[4][5] |
| TJupiter | 2.965 |
| Earth MOID | 0.410 AU |
| Jupiter MOID | 0.622 AU |
| Physical characteristics[2] | |
Mean diameter | 10.6 km (6.6 mi)[6] |
| 8.948±0.001 hours[7] | |
| 0.022[8] | |
| Comet total magnitude (M1) | 14.3 |
Physical characteristics
The comet nucleus is estimated to be roughly the size of Halley's Comet at 10.6 km (6.6 mi) in diameter with a low albedo of 0.022.[8] The nucleus is dark because hydrocarbons on the surface have been converted to a dark, tar like substance by solar ultraviolet radiation. The nucleus is large enough that even near aphelion (furthest distance from the Sun which is near the orbit of Jupiter) the comet remains brighter than about magnitude 21.
During the 2010 apparition the comet brightened to about apparent magnitude 8.[4] The most favorable apparition of 10P/Tempel 2 was in 1925 when it came within 0.35 AU (52 million km; 33 million mi) of Earth with an apparent magnitude of 6.5.[11][12]
Infrared spectroscopy conducted in July 2010 revealed the presence of CH3OH, C2H6, NH3 and HCN in trace amounts within its coma, with their peak intensities suggesting a possible existence of a distributed source that was released from the nucleus as sublimed icy grains.[13]
Proposed exploration
The Jet Propulsion Laboratory proposed a flyby of the comet with a flight spare of Mariner 4.[14] The probe was instead used for a Venus flyby as Mariner 5.[14]
It was the original target of the Comet Rendezvous Asteroid Flyby (CRAF) mission before it was switched to 22P/Kopff due to developmental delays,[15] until its eventual cancellation in 1992.[16]
10P/Tempel was to be the target of the NASA part of the International Comet Mission after transporting a European probe to a flyby of Halley's Comet.[17] The plan was to use Solar electric propulsion to get the craft to orbit the comet.[18] The program was cancelled in November 1979.[18]