128 Nemesis
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| Discovery[1] | |
|---|---|
| Discovered by | James Craig Watson |
| Discovery date | November 25, 1872 |
| Designations | |
| Pronunciation | /ˈnɛmᵻsɪs/ |
|
Named after
|
Nemesis |
| Main belt,[1] | |
| Orbital characteristics | |
| Epoch December 31, 2006 (JD 2454100.5) | |
| Aphelion | 463.605 Gm (3.099 AU) |
| Perihelion | 359.010 Gm (2.400 AU) |
| 411.307 Gm (2.749 AU) | |
| Eccentricity | 0.127 |
| 1665.175 d (4.56 a) | |
|
Average orbital speed
|
17.89 km/s |
| 181.168° | |
| Inclination | 6.254° |
| 76.457° | |
| 302.407° | |
| Physical characteristics | |
| Dimensions | 188.16 km[1] 184.19 ± 5.19[2] km |
| Mass | (5.97 ± 2.56) × 1018[2] kg |
|
Mean density
|
1.82 ± 0.79[2] g/cm3 |
| 0.0526 m/s² | |
| 0.0995 km/s | |
| 39 hr[1] | |
| Albedo | 0.05[1] |
| Temperature | ~168 K |
|
Spectral type
|
C[1] |
| Nemesis Family | |
| 10.46 to 13.58 | |
| 7.49[1] | |
128 Nemesis is a large 188 km main-belt asteroid, of carbonaceous composition. It rotates rather slowly, taking about one and half Earth days (39 hours)[1] to complete one revolution.[3] Nemesis is the largest member of the Nemesian asteroid family bearing its name. It was discovered by J. C. Watson on November 25, 1872,[1] and named after Nemesis, the goddess of retribution in Greek mythology. Nemesis is also the name of a hypothetical companion star of the Sun.
It is categorized as a C-type asteroid,[4] indicating a primitive carbonaceous composition. Based on IRAS data Nemesis is about 188 km in diameter and is around the 33rd largest main-belt asteroid.[5] The 39 hour rotation period is the second longest for an asteroid more than 150 km in diameter.[6]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ 2.0 2.1 2.2 Lua error in package.lua at line 80: module 'strict' not found. See Table 1.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Lua error in package.lua at line 80: module 'strict' not found. See appendix A.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
External links
- Orbital simulation from JPL (Java) / Ephemeris
