132 Aethra

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
Lightcurve-based 3D-model of Aethra
Discovery
Discovered byJames C. Watson
Discovery date13 June 1873
Designations
(132) Aethra
Pronunciation/ˈiːθrə/[1]
Named after
Aethra
A873 LA; 1922 XB;
1949 MD; 1953 LF
Mars crosser
Orbital characteristics[2]
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)
Eccentricity0.39036
4.21 yr (1537.7 d)
17.72 km/s
38.271°
0° 14m 2.796s / day
Inclination24.997°
258.408°
255.216°
Physical characteristics
Mean diameter
42.87±1.6 km[2]
44.47±0.74 km[3]
Mass(1.59 ± 0.89/0.42)×1017 kg[3]
Mean density
3.447 ± 1.935/0.923 g/cm3[3]
5.1684 h (0.21535 d)[2]
0.1990±0.015[2]
M
8.96[2]

    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.[4][5]

    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.

    References
    1. Noah Webster (1884) A Practical Dictionary of the English Language
    2. "JPL Small-Body Database Browser: 132 Aethra" (2000-06-10 last obs). Retrieved 12 May 2016.
    3. Fienga, A.; Avdellidou, C.; Hanuš, J. (February 2020). "Asteroid masses obtained with INPOP planetary ephemerides". Monthly Notices of the Royal Astronomical Society. 492 (1). doi:10.1093/mnras/stz3407.
    4. Herget, Paul (1938). "The orbit and perturbations of (132) Aethra". Astronomical Journal. 47 (1081): 17–23. Bibcode:1938AJ.....47...17H. doi:10.1086/105455.
    5. Fred William Price (2000). The Planet Observer's Handbook. Cambridge University Press. p. 192. ISBN 978-0-521-78981-3.
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