120 Lachesis

From Wikipedia, the free encyclopedia
Jump to navigation Jump to search

120 Lachesis
Discovery
Discovered by Alphonse Borrelly
Discovery date 10 April 1872
Designations
MPC designation (120) Lachesis
Pronunciation /ˈlækɪsɪs/
Named after
Lachesis
 
Main belt
Orbital characteristics[1]
Epoch 31 July 2016 (JD 2457600.5)
Uncertainty parameter 0
Observation arc 143.70 yr (52485 d)
Aphelion 3.2814 AU (490.89 Gm)
Perihelion 2.95390 AU (441.897 Gm)
3.11767 AU (466.397 Gm)
Eccentricity 0.052528
5.50 yr (2010.7 d)
16.86 km/s
56.2095°
0° 10m 44.558s / day
Inclination 6.9643°
341.193°
232.822°
Earth MOID 1.95464 AU (292.410 Gm)
Jupiter MOID 1.72275 AU (257.720 Gm)
TJupiter 3.204
Physical characteristics
Dimensions 174.10±2.9 km (IRAS)[2]
Mass 5.5×1018 kg
Equatorial surface gravity
0.0487 m/s²
Equatorial escape velocity
0.0920 km/s
46.551 h (1.9396 d)[2][3]
0.0463±0.002[2]
Temperature ~158 K
C[4]
7.75[2]

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.[5] 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.[6]

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 has the longest rotation period of an asteroid more than 150 km in diameter.[7] As a primitive C-type asteroid[4] it is probably composed of carbonaceous material.

References[edit]

  1. ^ Yeomans, Donald K., "120 Lachesis", JPL Small-Body Database Browser, NASA Jet Propulsion Laboratory, retrieved 2013-03-25. 
  2. ^ a b c d "JPL Small-Body Database Browser: 120 Lachesis". Jet Propulsion Laboratory. Retrieved 12 May 2016. 
  3. ^ a b Pilcher, Frederick (July 2009), "Rotation Period Determinations for 120 Lachesis, 131 Vala 157 Dejanira, and 271 Penthesilea", The Minor Planet Bulletin, 36 (3), pp. 100–102, Bibcode:2009MPBu...36..100P. 
  4. ^ a b Tedesco, E. F.; et al. (February 1989), "A three-parameter asteroid taxonomy", Astronomical Journal, 97, pp. 580–606, Bibcode:1989AJ.....97..580T, doi:10.1086/115007. 
  5. ^ Schmadel, Lutz D. (2003), Dictionary of Minor Planet Names, 1 (5th ed.), Springer, p. 26, ISBN 3540002383. 
  6. ^ Dunham, D. W.; et al. (September 2002), "Asteroidal occultation results multiply helped by Hipparcos", The Minor Planet Bulletin, 73 (3), p. 662, Bibcode:2002MmSAI..73..662D. 
  7. ^ "JPL Small-Body Database Search Engine: diameter > 150 (km) and rot_per > 24 (h)". JPL Solar System Dynamics. Retrieved 2015-06-06. 

External links[edit]