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Aethra (minor planet designation: 132 Aethra) is a metallic asteroid and Mars-crosser on an eccentric orbit from the asteroid belt. It measures approximately 40 kilometers in diameter.

132 Aethra
132Aethra (Lightcurve Inversion).png
Lightcurve-based 3D-model of Aethra
Discovered byJames C. Watson
Discovery date13 June 1873
MPC designation(132) Aethra
Named after
A922 XB; 1949 MD; 1953 LF
Mars crosser
Orbital characteristics[1]
Epoch 31 July 2016 (JD 2457600.5)
Uncertainty parameter 0
Observation arc142.50 yr (52049 d)
Aphelion3.6250 AU (542.29 Gm)
Perihelion1.5895 AU (237.79 Gm)
2.6073 AU (390.05 Gm)
4.21 yr (1537.7 d)
17.72 km/s
0° 14m 2.796s / day
Physical characteristics
Dimensions35.83±6.59 km[2]
42.87±1.6 km[1]
Mass(0.41±2.71)×1018 kg[2]
5.1684 h (0.21535 d)[1]

It was discovered by James Craig Watson in 1873 and is the first such Mars-crosser asteroid to be identified. As a Mars-crosser asteroid, Aethra is the lowest numbered asteroid to not have proper orbital elements due to recurring perturbations by Mars. It has a rather eccentric orbit that sometimes brings it closer to the Sun than the planet Mars.

With an original observation arc of only 22 days, 132 Aethra was a lost asteroid between 1873 and 1922.[3][4]

The varying light curve of the asteroid implies an elongated or irregular shape for its body.

It is named after Aethra, the mother of Theseus in Greek mythology.


  1. ^ a b c d e "JPL Small-Body Database Browser: 132 Aethra" (2000-06-10 last obs). Retrieved 12 May 2016.
  2. ^ a b Carry, B. (December 2012). "Density of asteroids" (PDF). Planetary and Space Science. 73 (1): 98–118. arXiv:1203.4336. Bibcode:2012P&SS...73...98C. doi:10.1016/j.pss.2012.03.009. Retrieved 2 November 2017. See Table 1.
  3. ^ Herget, Paul (1938). "The orbit and perturbations of (132) Aethra". Astronomical Journal. 47 (1081): 17–23. Bibcode:1938AJ.....47...17H. doi:10.1086/105455.
  4. ^ Fred William Price (2000). The Planet Observer's Handbook. Cambridge University Press. p. 192. ISBN 978-0-521-78981-3.

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