132 Aethra
Lightcurve-based 3D-model of Aethra | |
| Discovery | |
|---|---|
| Discovered by | James C. Watson |
| Discovery site | Ann Arbor, Michigan, United States |
| Discovery date | 13 June 1873 |
| Designations | |
| (132) Aethra | |
| Pronunciation | /ˈiːθrə/ |
Named after | Aethra |
| A873 LA · A922 XB · 1949 MD · 1953 LF | |
| Mars crosser | |
| Orbital characteristics | |
| Epoch 21 November 2025 (JD 2461000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 152.30 yr (55628 d) |
| Aphelion | 3.6230 AU (541.99 Gm) |
| Perihelion | 1.6012 AU (239.54 Gm) |
| 2.6121 AU (390.76 Gm) | |
| Eccentricity | 0.3870 |
| 4.2217 yr (1541.9 d) | |
Average orbital speed | 17.72 km/s |
| 113.0611° | |
| 0° 14m 0.24s / day | |
| Inclination | 24.9835° |
| 258.0509° | |
| 255.6188° | |
| Earth MOID | 0.7822 AU |
| Jupiter MOID | 2.2051 AU |
| TJupiter | 3.176 |
| Physical characteristics | |
| 42.87±1.6 km 44.47±0.74 km | |
| Mass | (1.59 ± 0.89/0.42)×1017 kg |
Mean density | 3.447 ± 1.935/0.923 g/cm3 |
| 5.1684 h (0.21535 d) | |
| 0.1990±0.015 | |
| M-type (Tholen) Xe-type (Bus) | |
| 8.96 | |
132 Aethra is a metallic asteroid and Mars-crosser on an eccentric orbit from the asteroid belt. It was discovered by James Craig Watson on 13 June 1873 in Ann Arbor, Michigan, and is the first Mars-crossing asteroid to be identified. It subsequently became a lost asteroid, and was only rediscovered in December 1922. It is named after Aethra, the mother of Theseus in Greek mythology.
Aethra measures approximately 43–44 kilometers in diameter and has a rotation period slightly longer than five hours. It is the largest and brightest of the Mars-crossers and is classified as an M-type asteroid under the Tholen classification scheme. Its surface is relatively reflective and is likely composed of various silicate, hydroxide, and iron-bearing minerals.