Astronomy:120 Lachesis
_Lachesis.png) 3D convex shape model of 120 Lachesis | |
| Discovery | |
|---|---|
| Discovered by | Alphonse Borrelly |
| Discovery date | 10 April 1872 |
| Designations | |
| (120) Lachesis | |
| Pronunciation | /ˈlækɪsɪs/ LAK-iss-iss[1] |
| Named after | Lachesis |
| A872 GB; 1910 CF; 1918 UB | |
| Minor planet category | Main belt |
| Adjectives | Lachesian (/læˈkiːʃ(i)ən, ləˈkiːʒən/ la-KEE-sh(ee-)ən, lə-KEE-zhən) |
| Orbital characteristics[2] | |
| Epoch 31 July 2016 (JD 2457600.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 143.70 yr (52485 d) |
| |{{{apsis}}}|helion}} | 3.2814 astronomical unit|AU (490.89 Gm) |
| |{{{apsis}}}|helion}} | 2.95390 AU (441.897 Gm) |
| 3.11767 AU (466.397 Gm) | |
| Eccentricity | 0.052528 |
| Orbital period | 5.50 yr (2010.7 d) |
| Average Orbital speed | 16.86 km/s |
| Mean anomaly | 56.2095° |
| Mean motion | 0° 10m 44.558s / day |
| Inclination | 6.9643° |
| Longitude of ascending node | 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 | 155.132±1.133 km (IRAS)[2] |
| Mass | 5.5×1018 kg |
Equatorial surface gravity | 0.0487 m/s2 |
Equatorial escape velocity | 0.0920 km/s |
| Rotation period | 46.551 h (1.9396 d)[2][3] |
| Geometric albedo | 0.0463±0.002[2] |
| Physics | ~158 K |
| C[4] | |
| Absolute magnitude (H) | 7.75[2] |
Lachesis (minor planet designation: 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]
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[7] with the longest rotation period of an asteroid more than 150 km in diameter.[8] As a primitive C-type asteroid[4] it is probably composed of carbonaceous material.
References
- ↑ "Lachesis". Lachesis. Oxford University Press. http://www.lexico.com/definition/Lachesis.
- ↑ 2.0 2.1 2.2 2.3 2.4 "JPL Small-Body Database Browser: 120 Lachesis". Jet Propulsion Laboratory. https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=120.
- ↑ 3.0 3.1 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.
- ↑ 4.0 4.1 Tedesco, E. F. et al. (February 1989), "A three-parameter asteroid taxonomy", Astronomical Journal 97: 580–606, doi:10.1086/115007, Bibcode: 1989AJ.....97..580T.
- ↑ Schmadel, Lutz D. (2003), Dictionary of Minor Planet Names, 1 (5th ed.), Springer, p. 26, ISBN 3540002383, https://books.google.com/books?id=VoJ5nUyIzCsC&pg=PA26.
- ↑ 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.
- ↑ 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. https://ssd.jpl.nasa.gov/sbdb_query.cgi?obj_group=all;obj_kind=all;obj_numbered=all;OBJ_field=0;ORB_field=0;combine_mode=AND;c1_group=OBJ;c1_item=Ap;c1_op=%3E;c1_value=150;c2_group=OBJ;c2_item=As;c2_op=%3E;c2_value=24;table_format=HTML;max_rows=50;format_option=comp;c_fields=AcBhBgBjBiBnBsAiApAs;.cgifields=format_option;.cgifields=ast_orbit_class;.cgifields=combine_mode;.cgifields=table_format;.cgifields=obj_kind;.cgifields=obj_group;.cgifields=obj_numbered;.cgifields=com_orbit_class&query=1&c_sort=AsD.
External links
- 120 Lachesis at AstDyS-2, Asteroids—Dynamic Site
- 120 Lachesis at the JPL Small-Body Database
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