Peggy is the informal name for a former moonlet in the outermost part of Saturn's Ring A, orbiting 136,775 kilometres (84,988 mi) away from the planet. The moonlet was discovered by the Cassini Imaging Team in 2013 and it may likely be exiting Saturn's A Ring.[1] No direct image of Peggy has ever been made.[4] Similar moons to Peggy include Bleriot, Earhart and Santos-Dumont among others.
 | |
| Discovery[1] | |
|---|---|
| Discovered by | Cassini Imaging Team |
| Discovery date | 2013[2] |
| Orbital characteristics | |
| 136,775.20 ±0.03km[3] | |
| Eccentricity | ≈ 0.000 |
| Inclination | ≈ 0.0 |
| Satellite of | Saturn |
| Group | outer A ring moonlet |
| Physical characteristics | |
| 1 kilometre (0.62 mi)[1] | |
| assumed synchronous | |
Etymology
editThe name of the moonlet comes from the mother-in-law of Carl D. Murray, a professor at the Queen Mary University of London.[4] Murray named it after his mother-in-law because it was her 80th birthday at the time.[5]
Discovery
editThe moonlet was first discovered in 2013, although its discovery was possible in 2012.[4] Cassini took 2 images of the edge of Saturn's A Ring, thereby ruling out it being a cosmic ray artifact.[3] There were disturbances at the edges of Saturn's A Ring, with one of these being approximately 20% brighter than its surroundings. There were also protuberances at the edge of the usually smooth A Ring.[6]
Collision
editWhen it was first discovered, no similar object has been discovered in Saturn's main rings.[3] The moonlet was then seen again in 2014 but it was much dimmer than it was in 2013. Carl Murray suggests that there may have been a collision or was gravitationally ejected, though without evidence. In Cassini observations past 2014, Peggy appears to be broken into two pieces, with the other being named Peggy B.[2]
References
edit- ^ a b c "Commotion at Ring's Edge May Be Effect of Small Icy Object". Jet Propulsion Laboratory. Retrieved 3 November 2022.
- ^ a b "The (Not So) Sad Story of Peggy, Saturn's Newest Moon". National Geographic. 27 January 2015. Archived from the original on December 4, 2021. Retrieved 3 November 2022.
- ^ a b c Murray, C. D.; Cooper, N. J.; Williams, G. A.; Attree, N. O.; Boyer, J. S. (2014-03-28). "The discovery and dynamical evolution of an object at the outer edge of Saturn's a ring". Icarus. 236: 165–168. Bibcode:2014Icar..236..165M. doi:10.1016/j.icarus.2014.03.024.
- ^ a b c "To see finally the face of Peggy". BBC News. 13 January 2017. Retrieved 3 November 2022.
- ^ "A Moon Is Born: Say Hello to 'Peggy' at Saturn". NBC. 15 April 2014. Retrieved 3 November 2022.
- ^ "NASA Cassini Images May Reveal Birth of a Saturn Moon". JPL. Retrieved 3 November 2022.