31 Euphrosyne
VLT-SPHERE image of Euphrosyne, deconvolved with the MISTRAL algorithm. | |
| Discovery | |
|---|---|
| Discovered by | J. Ferguson |
| Discovery date | September 1, 1854 |
| Designations | |
| (31) Euphrosyne | |
| Pronunciation | /juːˈfrɒsɪniː/ |
Named after | Εὐφροσύνη Eyphrosynē |
| A907 GP; A918 GB | |
| Main belt | |
| Adjectives | Euphrosynean /juːfrɒsɪˈniːən/ |
| Orbital characteristics | |
| Epoch April 27, 2019 (JD 2458600.5) | |
| Aphelion | 3.8523 AU (576.296 Gm) |
| Perihelion | 2.4585 AU (367.786 Gm) |
| 3.1554 AU (472.041 Gm) | |
| Eccentricity | 0.2209 |
| 5.61 yr (2041.585 d) | |
| 87.1671° | |
| Inclination | 26.3033° |
| 31.1186° | |
| 61.4704° | |
| Known satellites | 1 |
| Physical characteristics | |
| Dimensions | (294±6) × (280±10) × (248±6) km |
| 268±4 km 267.1±2.6 km (IRAS) 268±6 km | |
| Flattening | 0.14 |
| Mass | (16.5±2.6)×1018 kg (17±3)×1018 kg |
Mean density | 1.64±0.27 g/cm3 1.66±0.24 g/cm3 |
| 0.230400 d (5.529595 h) | |
| 0.05 0.0543 | |
| C | |
| 10.16 to 13.61 | |
| 6.86 | |
31 Euphrosyne is one of the largest asteroids (approximately tied for 7th place, to within measurement uncertainties). It was discovered by James Ferguson on September 1, 1854, the first asteroid found from North America. It is named after Euphrosyne, one of the Charites in Greek mythology. In 2019 a small companion was discovered. It is the third-roundest known asteroid (after 1 Ceres and 10 Hygiea); this is thought to be due to having re-accreted after being disrupted by a collision, and it is not close to hydrostatic equilibrium.