128 Nemesis
.gif) | |
| Discovery[1] | |
|---|---|
| Discovered by | James Craig Watson |
| Discovery date | 25 November 1872 |
| Designations | |
| Pronunciation | /ˈnɛmᵻsɪs/ |
Named after | Nemesis |
| Main belt,[1] | |
| Orbital characteristics[1] | |
| Epoch 31 July 2016 (JD 2457600.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 143.39 yr (52373 d) |
| Aphelion | 3.09824 AU (463.490 Gm) |
| Perihelion | 2.40068 AU (359.137 Gm) |
| 2.74946 AU (411.313 Gm) | |
| Eccentricity | 0.12685 |
| 4.56 yr (1665.2 d) | |
Average orbital speed | 17.89 km/s |
| 215.699° | |
| 0° 12m 58.277s / day | |
| Inclination | 6.24500° |
| 76.2475° | |
| 303.860° | |
| Earth MOID | 1.40918 AU (210.810 Gm) |
| Jupiter MOID | 2.36425 AU (353.687 Gm) |
| Jupiter Tisserand parameter | 3.326 |
| Physical characteristics | |
| Dimensions |
188.16±4.0 km[1] 184.19 ± 5.19 km[2] |
| Mass | (5.97 ± 2.56) × 1018 kg[2] |
Mean density | 1.82 ± 0.79 g/cm3[2] |
Equatorial surface gravity | 0.0526 m/s² |
Equatorial escape velocity | 0.0995 km/s |
| 77.81 h (3.242 d)[1] | |
| 0.0504±0.002[1] | |
| Temperature | ~168 K |
| 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 was also the name of a hypothetical companion star of the Sun, which does not exist.
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 2 3 4 5 6 7 8 9 10 "JPL Small-Body Database Browser: 128 Nemesis" (2011-06-13 last obs (arc=138 years)). Jet Propulsion Laboratory. Retrieved 12 May 2016.
- 1 2 3 Carry, B. (December 2012), "Density of asteroids", Planetary and Space Science, 73, pp. 98–118, arXiv:1203.4336
, Bibcode:2012P&SS...73...98C, doi:10.1016/j.pss.2012.03.009. See Table 1. - ↑ Scaltriti, F.; Zappala, V.; Schober, H. J. (January 1979), "The rotations of 128 Nemesis and 393 Lampetia - The longest known periods to date", Icarus, 37, pp. 133–141, Bibcode:1979Icar...37..133S, doi:10.1016/0019-1035(79)90121-0.
- ↑ DeMeo, Francesca E.; et al. (July 2009), "An extension of the Bus asteroid taxonomy into the near-infrared" (PDF), Icarus, 202 (1), pp. 160–180, Bibcode:2009Icar..202..160D, doi:10.1016/j.icarus.2009.02.005, archived from the original (PDF) on 2014-03-17, retrieved 2013-04-08. See appendix A.
- ↑ "JPL Small-Body Database Search Engine: asteroids and orbital class (IMB or MBA or OMB) and diameter > 188.1 (km)". JPL's Solar System Dynamics Group. Retrieved 2012-04-17.
- ↑ "JPL Small-Body Database Search Engine: diameter > 150 (km) and rot_per > 24 (h)". JPL Solar System Dynamics. Retrieved 2015-06-06.
External links
- Orbital simulation from JPL (Java) / Ephemeris
- 128 Nemesis at the JPL Small-Body Database
