14871 Pyramus

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14871 Pyramus
Discovery [1]
Discovered by L. D. Schmadel
F. Börngen
Discovery site Karl Schwarzschild Obs.
Discovery date 13 October 1990
MPC designation (14871) Pyramus
Named after
(Classical mythology)
1990 TH7 · 1972 TJ3
1978 TW4
main-belt[1] · (outer)[3]
background[4] · Zhongguo[5]
Orbital characteristics[3]
Epoch 23 March 2018 (JD 2458200.5)
Uncertainty parameter 0
Observation arc 62.73 yr (22,913 d)
Aphelion 4.0337 AU
Perihelion 2.5706 AU
3.3021 AU
Eccentricity 0.2215
6.00 yr (2,192 d)
0° 9m 51.48s / day
Inclination 0.9882°
Physical characteristics
Mean diameter
9 km (estimated at 0.06)[6]

14871 Pyramus, provisional designation 1990 TH7, is a dark Zhongguo asteroid from the outermost region of the asteroid belt, approximately 9 kilometers (6 miles) in diameter. It was discovered on 13 October 1990 by German astronomers Lutz Schmadel and Freimut Börngen at the Karl Schwarzschild Observatory in Tautenburg, Germany.[1] The asteroid was named for Pyramus from classical mythology.[2]

Orbit and classification[edit]

Pyramus is a non-family asteroid from the main belt's background population.[4] It is a member of the small group of Zhongguo asteroids, located in the 2 : 1 mean motion resonance with the giant planet Jupiter. Contrary to the nearby unstable Griqua group, the orbits of the Zhongguos are stable over half a billion years.[5][8]

It orbits the Sun in the outer main-belt at a distance of 2.6–4.0 AU once every 6.00 years (2,192 days; semi-major axis of 3.3 AU). Its orbit has an eccentricity of 0.22 and an inclination of 1° with respect to the ecliptic.[3] The first precovery was taken at Palomar Observatory in 1954, extending the asteroid's observation arc by 36 years prior to its discovery.[1]

Physical characteristics[edit]

Diameter and albedo[edit]

According to the survey carried out by NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, Pyramus measures 9.2 kilometers in diameter and its surface has an albedo of 0.069.[7] This is in line with a generic absolute magnitude-to-diameter conversion that gives a diameter of 4 to 9 kilometers for an albedo between 0.05 and 0.25.[6]


As of 2018, no rotational lightcurve has been obtained of Pyramus. The asteroid's rotation period, pole and shape remain unknown.[3][9]


This minor planet was named from Greco-Roman mythology after Pyramus, the lover of Thisbe (see minor planet 88 Thisbe) from which the tragedy of Romeo and Juliet ultimately originated. As narrated in Ovid's Metamorphoses, the two ill-fated lovers committed suicide as their parents were against their marriage. The asteroid's name was proposed by Austrian amateur astronomer Herbert Raab. The citation mentions that the "two lovers are now finally united forever in the asteroid belt".[2] The approved naming citation was published by the Minor Planet Center on 6 January 2003 (M.P.C. 47301).[10]


  1. ^ a b c d "14871 Pyramus (1990 TH7)". Minor Planet Center. Retrieved 6 April 2016. 
  2. ^ a b c Schmadel, Lutz D. (2006). Dictionary of Minor Planet Names – (14871) Pyramus, Addendum to Fifth Edition: 2003–2005. Springer Berlin Heidelberg. pp. 88–89. ISBN 978-3-540-34360-8. Retrieved 6 April 2016. 
  3. ^ a b c d e "JPL Small-Body Database Browser: 14871 Pyramus (1990 TH7)" (2017-03-27 last obs.). Jet Propulsion Laboratory. Retrieved 26 June 2017. 
  4. ^ a b "Small Bodies Data Ferret". Nesvorny HCM Asteroid Families V3.0. Retrieved 26 April 2018. 
  5. ^ a b Roig, F.; Nesvorný, D.; Ferraz-Mello, S. (September 2002). "Asteroids in the 2 : 1 resonance with Jupiter: dynamics and size distribution [ Erratum: 2002MNRAS.336.1391R ]". Monthly Notices of the Royal Astronomical Society. 335 (2): 417–431. Bibcode:2002MNRAS.335..417R. doi:10.1046/j.1365-8711.2002.05635.x. Retrieved 6 April 2016. 
  6. ^ a b "Absolute Magnitude (H)". NASA/JPL. Retrieved 6 April 2016. 
  7. ^ a b c Masiero, Joseph R.; Mainzer, A. K.; Grav, T.; Bauer, J. M.; Cutri, R. M.; Dailey, J.; et al. (November 2011). "Main Belt Asteroids with WISE/NEOWISE. I. Preliminary Albedos and Diameters". The Astrophysical Journal. 741 (2): 20. arXiv:1109.4096Freely accessible. Bibcode:2011ApJ...741...68M. doi:10.1088/0004-637X/741/2/68. Retrieved 3 December 2016. 
  8. ^ Roig, F.; Nesvorný, D.; Ferraz-Mello, S. (November 2002). "Erratum: Asteroids in the 2 : 1 resonance with Jupiter: dynamics and size distribution". Monthly Notices of the Royal Astronomical Society. 336 (4): 1391–1392. Bibcode:2002MNRAS.336.1391R. doi:10.1046/j.1365-8711.2002.06105.x. Retrieved 6 April 2016. 
  9. ^ "LCDB Data for (14871) Pyramus". Asteroid Lightcurve Database (LCDB). Retrieved 26 June 2017. 
  10. ^ "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 20 May 2016. 

External links[edit]