1162 Larissa

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1162 Larissa
Discovery [1]
Discovered by K. Reinmuth
Discovery site Heidelberg Obs.
Discovery date 5 January 1930
MPC designation (1162) Larissa
Named after
Larissa (Greek city)[2]
1930 AC · 1948 KJ
main-belt · (outer)[1]
Orbital characteristics[1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc 87.50 yr (31,958 days)
Aphelion 4.3705 AU
Perihelion 3.5082 AU
3.9393 AU
Eccentricity 0.1095
7.82 yr (2,856 days)
0° 7m 33.96s / day
Inclination 1.8856°
Jupiter MOID 0.6683 AU
Physical characteristics
Dimensions 41.3±0.9 km[4]
42.243±0.111 km[4]
44.32 km (derived)[3]
48.59±1.50 km[5]
6.514±0.003 h[6][a]
6.516±0.002 h [7]
6.520±0.0021 h[8]
13.0 h (dated)[9]
0.1153 (derived)[3]
Tholen = P [1][3] · M[4]
B–V = 0.761 [1]
U–B = 0.226 [1]
9.314±0.001 (R)[8] · 9.40[4] · 9.42±0.43[10] · 9.44[1][5] · 9.73[3][11]

1162 Larissa, provisional designation 1930 AC, is a metallic Hildian asteroid from the outermost regions of the asteroid belt, approximately 43 kilometers in diameter. It was discovered on 5 January 1930, by astronomer German astronomer Karl Reinmuth at Heidelberg Observatory in southwest Germany.[12] The asteroid was named after the Greek city of Larissa.[2]

Orbit and classification[edit]

Larissa belongs to the Hilda group located outermost part of the main-belt.[3] Asteroids in this dynamical group have semi-major axis between 3.7 and 4.2 AU and stay in a 3:2 resonance with the gas giant Jupiter. Larissa, however, is a background asteroid and not a member of the (collisional) Hilda family (101).[13]

The asteroid orbits the Sun at a distance of 3.5–4.4 AU once every 7 years and 10 months (2,856 days). Its orbit has an eccentricity of 0.11 and an inclination of 2° with respect to the ecliptic.[1] The body's observation arc begins 15 days after its official discovery observation at Heidelberg.[12]

Physical characteristics[edit]

Larissa has been characterized as a metallic M-type asteroid by the Wide-field Infrared Survey Explorer (WISE).[4] In the Tholen classification, the asteroid a primitive P-type asteroid, which typically have lower albedos than those measured by WISE and Akari (see below).[1]

Rotation period[edit]

In April 2017, a rotational lightcurve of Larissa was obtained from photometric observations by American astronomers Brian Warner and Robert Stephens at the Center for Solar System Studies (U81/U82) in California. Lightcurve analysis gave a well-defined rotation period of 6.514 hours with a brightness variation of 0.12 magnitude (U=3).[6][a]

In May 2010, a lightcurve form the Oakley Southern Sky Observatory (E09) in Australia, gave a concurring period of 6.516 hours with an amplitude of 0.20 magnitude (U=3).[7] Another period of 6.520 hours (Δ0.12 mag) was measured at the Palomar Transient Factory in October 2012 (U=2).[8] The first photometric observation of Larissa, which gave a period of 13.0 hours, is now considered incorrect (U=1).[9]

Diameter and albedo[edit]

According to the surveys carried out by the Japanese Akari satellite and the NEOWISE mission of NASA's WISE telescope, Larissa measures between 41.3 and 48.59 kilometers in diameter and its surface has an albedo between 0.127 and 0.18.[4][5] The Collaborative Asteroid Lightcurve Link derives an albedo of 0.1153 and a diameter of 44.32 kilometers based on an absolute magnitude of 9.73.[3]


This minor planet was named for the city of Larissa, capital of the Thessaly region in Greece, after which the asteroid 1161 Thessalia was named. The name was also given to Larissa (Neptune VII), one of the moons of Neptune. The official naming citation was mentioned in The Names of the Minor Planets by Paul Herget in 1955 (H 108).[2]


  1. ^ a b Lightcurve plot of (1162) Larissa, by Stephens and Warner (2017), Center for Solar System Studies (CS3)


  1. ^ a b c d e f g h i "JPL Small-Body Database Browser: 1162 Larissa (1930 AC)" (2017-07-05 last obs.). Jet Propulsion Laboratory. Retrieved 7 September 2017.
  2. ^ a b c Schmadel, Lutz D. (2007). Dictionary of Minor Planet Names – (1162) Larissa. Springer Berlin Heidelberg. p. 98. ISBN 978-3-540-00238-3. Retrieved 7 September 2017.
  3. ^ a b c d e f g "LCDB Data for (1162) Larissa". Asteroid Lightcurve Database (LCDB). Retrieved 7 September 2017.
  4. ^ a b c d e f g h Grav, T.; Mainzer, A. K.; Bauer, J.; Masiero, J.; Spahr, T.; McMillan, R. S.; et al. (January 2012). "WISE/NEOWISE Observations of the Hilda Population: Preliminary Results". The Astrophysical Journal. 744 (2): 15. arXiv:1110.0283. Bibcode:2012ApJ...744..197G. doi:10.1088/0004-637X/744/2/197. Retrieved 7 September 2017.
  5. ^ a b c d Usui, Fumihiko; Kuroda, Daisuke; Müller, Thomas G.; Hasegawa, Sunao; Ishiguro, Masateru; Ootsubo, Takafumi; et al. (October 2011). "Asteroid Catalog Using Akari: AKARI/IRC Mid-Infrared Asteroid Survey". Publications of the Astronomical Society of Japan. 63 (5): 1117–1138. Bibcode:2011PASJ...63.1117U. doi:10.1093/pasj/63.5.1117. Retrieved 7 September 2017.
  6. ^ a b Warner, Brian D.; Stephens, Robert D. (July 2017). "Lightcurve Analysis of Hilda Asteroids at the Center for Solar System Studies: 2016 December thru 2017 April". The Minor Planet Bulletin. 44 (3): 220–222. Bibcode:2017MPBu...44..220W. ISSN 1052-8091. Retrieved 7 September 2017.
  7. ^ a b Pligge, Zachary; Monnier, Adam; Pharo, John; Stolze, Kellen; Yim, Arnold; Ditteon, Richard (January 2011). "Asteroid Lightcurve Analysis at the Oakley Southern Sky Observatory: 2010 May". The Minor Planet Bulletin. 38 (1): 5–7. Bibcode:2011MPBu...38....5P. ISSN 1052-8091. Retrieved 7 September 2017.
  8. ^ a b c Waszczak, Adam; Chang, Chan-Kao; Ofek, Eran O.; Laher, Russ; Masci, Frank; Levitan, David; et al. (September 2015). "Asteroid Light Curves from the Palomar Transient Factory Survey: Rotation Periods and Phase Functions from Sparse Photometry". The Astronomical Journal. 150 (3): 35. arXiv:1504.04041. Bibcode:2015AJ....150...75W. doi:10.1088/0004-6256/150/3/75. Retrieved 7 September 2017.
  9. ^ a b Dahlgren, M.; Lahulla, J. F.; Lagerkvist, C.-I.; Lagerros, J.; Mottola, S.; Erikson, A.; et al. (June 1998). "A Study of Hilda Asteroids. V. Lightcurves of 47 Hilda Asteroids". Icarus. 133 (2): 247–285. Bibcode:1998Icar..133..247D. doi:10.1006/icar.1998.5919. Retrieved 7 September 2017.
  10. ^ Veres, Peter; Jedicke, Robert; Fitzsimmons, Alan; Denneau, Larry; Granvik, Mikael; Bolin, Bryce; et al. (November 2015). "Absolute magnitudes and slope parameters for 250,000 asteroids observed by Pan-STARRS PS1 - Preliminary results". Icarus. 261: 34–47. arXiv:1506.00762. Bibcode:2015Icar..261...34V. doi:10.1016/j.icarus.2015.08.007. Retrieved 7 September 2017.
  11. ^ Binzel, Richard P.; Sauter, Linda M. (February 1992). "Trojan, Hilda, and Cybele asteroids - New lightcurve observations and analysis". Icarus: 222–238. Bibcode:1992Icar...95..222B. doi:10.1016/0019-1035(92)90039-A. ISSN 0019-1035. Retrieved 7 September 2017.
  12. ^ a b "1162 Larissa (1930 AC)". Minor Planet Center. Retrieved 7 September 2017.
  13. ^ "Small Bodies Data Ferret". Nesvorny HCM Asteroid Families V3.0. Retrieved 7 September 2017.

External links[edit]