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May 16, 2021
After the discovery of the satellite Dactyl on the asteroid Ida in 1993, the discovery of satellites around other small bodies in the asteroid belt was a matter of time. Already in 2001, the first satellite was discovered near the asteroid Sylvia, and in 2004 - the second. Thus, Sylvia became the first asteroid to have two satellites discovered.
Asteroids belt between Mars and Jupiter (English)
The asteroid Sylvia (87 Sylvia in the catalog of the Minor Planet Center) was discovered by the English astronomer Norman Pogson in 1866 at the Madras Observatory in India and named after Rhea Sylvia, the mother of the legendary brothers Romulus and Remus, the founders of Rome. In 2005, they will be named after the discovered satellites of the asteroid.
Asteroid Sylvia belongs to the Cybele family. This is a group of asteroids located in the outer part of the Main Asteroid Belt at a distance of 3.3-3.7 AU. from the sun. The family is named after the largest representative - the asteroid Cybele.
Sylvia, with an average diameter of 253 km, is the eighth largest asteroid in the Main Belt. It is a rather dark asteroid with a high carbon content and a very low density, averaging 1.2 g / cm³, which indicates a high degree of porosity of this object. Probably, Sylvia is not a monolithic body, but is a so-called rubble pile - an unofficial term in planetary science for non-monolithic objects consisting of debris held together by their own gravity.
It is possible that the asteroid system with two satellites was formed as a result of the collision of the original asteroid with another body, followed by their complete destruction, after which part of the debris was collected in the body of the asteroid, and the other part formed satellites. By now, other asteroids with two satellites are also known.
Related articles:
Quasi-satellite of the Earth - The asteroid Kamoalev
https://orbiterchspacenews.blogspot.com/2021/05/quasi-satellite-of-earth-asteroid.html
Asteroid Gaspra
https://orbiterchspacenews.blogspot.com/2021/05/asteroid-gaspra.html
Related links:
ROSCOSMOS Press Release: https://www.roscosmos.ru/31058/
Moscow Planetarium: https://www.roscosmos.ru/tag/moskovskiy-planetariy/
Asteroid: https://www.roscosmos.ru/tag/asteroid/
Images, Text, Credits: ROSCOSMOS/Moscow Planetarium/Orbiter.ch Aerospace/Roland Berga.
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