120 Lachesis

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120 Lachesis
Discovery
Discovered by Alphonse Borrelly
Discovery date 10 April 1872
Designations
Pronunciation /ˈlæksɪs/
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)
Jupiter Tisserand parameter 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.[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]