4179 Toutatis
Chang'e 2 image of Toutatis during its flyby.
|
|
| Discovery | |
|---|---|
| Discovered by | Christian Pollas |
| Discovery date | 4 January 1989 |
| Designations | |
|
Named after
|
Toutatis |
| 1934 CT; 1989 AC | |
Apollo  Alinda, Mars-crosser, NEO, PHA |
|
| Orbital characteristics | |
| Epoch 13 January 2016 (JD 2457400.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 29317 days (80.27 yr) |
| Aphelion | 4.1296 AU (617.78 Gm) |
| Perihelion | 0.93931 AU (140.519 Gm) |
| 2.5344 AU (379.14 Gm) | |
| Eccentricity | 0.62938 |
| 4.03 yr (1473.7 d) | |
|
Average orbital speed
|
16.69 km/s |
| 281.88° | |
| 0° 14m 39.372s / day | |
| Inclination | 0.44712° |
| 124.37° | |
| 278.73° | |
| Earth MOID | 0.006054 AU (905,700 km) |
| Jupiter MOID | 1.29451 AU (193.656 Gm) |
| Jupiter Tisserand parameter | 3.138 |
| Physical characteristics | |
| Dimensions | 4.75×2.4×1.95 km (±10%)(measured by Chang'e 2), 4.26×2.03×1.70 ± 0.08 km |
|
Mean radius
|
2.7 km |
| Mass | 5.0×1013 kg |
|
Mean density
|
2.1 g/cm³ |
|
Equatorial surface gravity
|
0.0010 m/s² |
|
Equatorial escape velocity
|
0.0019 km/s |
| 176 h (7.3 d) | |
| 0.13 | |
| Temperature | ~174 K |
| S | |
| 8.8 (when near Earth) to 22.4 | |
| 15.30 | |
4179 Toutatis (/tuːˈtɑːtᵻs/ too-TAH-tis) is an Apollo, Alinda, and Mars-crosser asteroid with a chaotic orbit produced by a 3:1 resonance with the planet Jupiter, a 1:4 resonance with the planet Earth, and frequent close approaches to the terrestrial planets, including Earth. With its close approaches, and being about 4.6 km across, it is listed as a potentially hazardous object, although the probability of a collision with Earth is minute.
On December 12, 2012 at 06:40 UT Toutatis passed within about 18 lunar distances of Earth. On December 13, the Chinese lunar probe Chang'e 2, launched in 2010 on a lunar mission, flew by Toutatis at a distance of 3.2 kilometers and a relative velocity of 10.73 km/s. Toutatis will approach Earth again in 2016, but will not make another notably close approach until 2069.
4179 Toutatis was first sighted on February 10, 1934, as object 1934 CT, but lost soon afterwards. It remained a lost asteroid for several decades until it was rediscovered on January 4, 1989, by Christian Pollas, and was named after the Celtic god of tribal protection Toutatis (Teutates).
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