|Properties of the orbit ( animation )|
|Orbit type||Main belt asteroid|
|Asteroid family||Euphrosyne family|
|Major semi-axis||3.152 AU|
|Perihelion - aphelion||2.445 AU - 3.859 AU|
|Inclination of the orbit plane||26.3 °|
|Length of the ascending node||31.2 °|
|Argument of the periapsis||61.8 °|
|Time of passage of the perihelion||May 10, 2012|
|Sidereal period of rotation||5 a 223 d|
|Mean orbital velocity||16.6 km / s|
|Medium diameter||267 km|
|Rotation period||5.5 h|
|Absolute brightness||6.7 likes|
(according to Tholen)
(according to SMASSII)
|Date of discovery||September 1, 1854|
|Source: Unless otherwise stated, the data comes from JPL Small-Body Database Browser . The affiliation to an asteroid family is automatically determined from the AstDyS-2 database . Please also note the note on asteroid items.|
With a diameter of 256 km, Euphrosyne is one of the largest asteroids in the main belt. The asteroid has a dark carbonaceous surface with an albedo of 0.05. It rotates around its own axis in around 5.5 hours.
Euphrosyne is the namesake of a complex family of roughly two thousand asteroids that share similar spectral properties and orbital elements. It is believed that they were formed by a collision about 280 million years ago. All members have relatively high inclines.
In 2019, a small satellite (S / 2019 (31) 1 alias Euphrosyne I) was discovered, which is believed to have been created by the same collision event as the family. Preliminary orbital calculations showed an orbital period of about 1.2 days and a semi-major axis of 670 km. VLT images suggest the moon is 4 km in diameter, assuming it has the same albedo as Euphrosyne.
- Natali Anderson: VLT Measures Main-Belt Asteroid Euphrosyne and Its Moon , on: sci-news from August 3, 2020
- Bin Yang at al. : Binary asteroid (31) Euphrosyne: Ice-rich and nearly spherical , on: arXix from July 16, 2020, PDF
- Bojan Novaković et al. : Families among high-inclination asteroids , in: Icarus 216 (1), November 2011, pp. 69–81, Bibcode: 2011Icar..216 ... 69N , doi: 10.1016 / j.icarus.2011.08.016