| Minorplanet | yes |
|---|---|
| Background |
|
| Discoverer | Alphonse Borrelly |
| Discovered | 10 April 1872 |
| Mpc name | (120) Lachesis |
| Alt names | A872 GB; 1910 CF; 1918 UB |
| Pronounced | /ˈlækᵻsɪs/ LAK-iss-iss[1] |
| Adjective | Lachesian (/læˈkiːʃ(i)ən,_ləˈkiːʒən/ la-KEE-sh(ee-)ən-,_-lə-KEE-zhən) |
| Named after | Lachesis |
| Mp category | Main belt |
| Epoch | 31 July 2016 (JD 2457600.5) |
| Semimajor | 3.11767 AU (466.397 Gm) |
| Perihelion | 2.95390 AU (441.897 Gm) |
| Aphelion | 3.2814 AU (490.89 Gm) |
| Eccentricity | 0.052528 |
| Period | 5.50 yr (2010.7 d) |
| Inclination | 6.9643° |
| Asc node | 341.193° |
| Arg peri | 232.822° |
| Mean anomaly | 56.2095° |
| Avg speed | 16.86 km/s |
| Dimensions | 155.132 ± 1.133 km (IRAS)[2] |
| Mass | 5.5×1018 kg |
| Surface grav | 0.0487 m/s2 |
| Escape velocity | 0.0920 km/s |
| Rotation | 46.551 h[2][3] |
| Abs magnitude | 7.75[2] |
| Albedo | 0.0463 ± 0.002[2] |
| Single temperature | ~158 K |
| Mean motion | / day |
| Observation arc | 143.70 yr (52485 d) |
| Uncertainty | 0 |
| Moid | 1.95464 AU (292.410 Gm) |
| Jupiter moid | 1.72275 AU (257.720 Gm) |
| Tisserand | 3.204 |
120 Lachesis is a large main-belt asteroid. It was discovered by French astronomer Alphonse Borrelly on April 10, 1872, and independently by German-American astronomer Christian Heinrich Friedrich Peters on April 11, 1872, then named after Lachesis, one of the Moirai, or Fates, in Greek mythology.[4] A Lachesean occultation of a star occurred in 1999 and was confirmed visually by five observers and once photoelectrically, with the chords yielding an estimated elliptical cross-section of 184 × 144 km.[5]
This body is orbiting the Sun with a period of 5.50 years and an eccentricity (ovalness) of 0.05. The orbital plane is inclined by 7° to the plane of the ecliptic. Photometric observations of this asteroid were made in early 2009 at the Organ Mesa Observatory in Las Cruces, New Mexico. The resulting light curve shows a synodic rotation period of 46.551 ± 0.002 hours with a brightness variation of 0.14 ± 0.02 in magnitude.[3] It is a very slow rotator[6] with the longest rotation period of an asteroid more than 150 km in diameter.[7] As a primitive C-type asteroid[8] it is probably composed of carbonaceous material.
References
- ^ "Lachesis". Lexico UK English Dictionary. Oxford University Press. Archived from the original on March 23, 2020.
- ^ "JPL Small-Body Database Browser: 120 Lachesis". Jet Propulsion Laboratory. Retrieved 18 Dec 2022.
- ^ Pilcher, Frederick (July 2009), "Rotation Period Determinations for 120 Lachesis, 131 Vala 157 Dejanira, and 271 Penthesilea", The Minor Planet Bulletin. 36 (3): 100–102, Bibcode:2009MPBu...36..100P
- ^ Schmadel, Lutz D. (2003), Dictionary of Minor Planet Names, Vol. 1, 5th ed., Springer, p. 26, ISBN 3540002383
- ^ Dunham, D. W. et al. (September 2002), "Asteroidal occultation results multiply helped by Hipparcos", The Minor Planet Bulletin. Vol. 73, no. 3, p. 662, Bibcode:2002MmSAI..73..662D
- ^ Bembrick, Colin & Allen, Bill (September 2005). "120 Lachesis - a very slow rotator". Bulletin of the Minor Planets Section of the Association of Lunar and Planetary Observers. 32 (3): 45–46. Bibcode:2005MPBu...32...45B
- ^ "JPL Small-Body Database Search Engine: diameter > 150 (km) and rot_per > 24 (h)". JPL Solar System Dynamics. Retrieved 2015-06-06.
- ^ Tedesco, E. F. et al. (February 1989), "A three-parameter asteroid taxonomy", Astronomical Journal. 97: 580–606, Bibcode:1989AJ.....97..580T. doi:10.1086/115007