Shepherd moon
As Shepherd Moons (also shepherd moons , shepherd moons , guard Monde ) refers to smaller natural satellites of giant planets or asteroids in the solar system , the orbits of the particles in the ring system distinguish with significant gaps or concentrate into separate individual rings. The name comes from the fact that they delimit the "flock" of the ring particles like a shepherd .
Due to their gravitational effect , they can collect particles or deflect them from their original orbit through orbital disturbances or rearrange them through orbit resonances . This causes gaps in the ring systems, such as the particularly distinctive Cassini division , as well as characteristic bands or leads to strange "twisted" deformations of rings.
The complex system of Saturn's rings has several such satellites. Three are more or less clearly assigned as shepherd moons ( Atlas for the A-ring and Prometheus and Pandora for the F-ring). The other five inner satellites Daphnis , Pan , Janus , Epimetheus and Aegaeon are also regarded as shepherd moons .
The Uranus has two Schäfer Monde on both sides of its epsilon-ring : Cordelia and Ophelia .
literature
- Arnold Hanslmeier : Introduction to Astronomy and Astrophysics . Spectrum, Berlin / Heidelberg 2007, ISBN 978-3-8274-1846-3 .