S/2020 S 4
| Discovery | |
|---|---|
| Discovered by | Edward Ashton, Brett J. Gladman |
| Discovery date | 2020 |
| Orbital characteristics[1] | |
| 18,235,500 km (11,331,000 mi) | |
| Eccentricity | 0.495 |
| 2.538 yrs (926.96 d) | |
| Inclination | 40.1° (to the ecliptic) |
| Satellite of | Saturn |
| Group | Gallic group |
| Physical characteristics | |
| 3 km | |
| 17.0 | |
S/2020 S 4 is the faintest natural satellite of Saturn. It was discovered by Edward Ashton, Brett J. Gladman, Jean-Marc Petit and Mike Alexandersen on June 24, 2020, and was announced on May 6, 2023 by the IAU Minor Planet Center after observations were collected over a long period of time to confirm the satellite's orbit that were taken between July 1, 2019 and July 9, 2021.[2]
Orbit
[edit]S/2020 S 4 is a highly eccentric satellite with an eccentricity of 0.495, it orbits Saturn at an average distance of 18.2 million km and an orbital period of 2 and a half years, with an inclination of 40.1° to the ecliptic, suggesting that it belongs to the Gallic group.[1] However, sometimes its moon group is disputed, and it may be included in the Inuit group.[3][4] It has been suggested that it was a fragment piece of Siarnaq that broke off a long time ago in a time-span of a few thousand years.[3]
The orbit of S/2020 S 4 is liberating in accordance of von Zeipel–Lidov–Kozai effect.[5]
Physical characteristics
[edit]S/2020 S 4 is estimated to be 3 km in diameter and currently the faintest known moon of Saturn having an absolute magnitude of 17.[1] Scott S. Sheppard and Tilmann Denk on the other hand, estimated it to be 2 km and 2 and a quarter km, respectively.[4][3] If these estimates were true, it would make S/2020 S 4 one of the smallest known irregular moons of Saturn.[3]
References
[edit]- ^ a b c "Planetary Satellite Mean Elements". Jet Propulsion Laboratory. California Institute of Technology. Retrieved 6 May 2023.
- ^ "MPEC 2023-J38 : S/2020 S 4". Minor Planet Electronic Circular. Minor Planet Center. Retrieved 6 May 2023.
- ^ a b c d "S/2020 S 4". Tilmann's Website. Tilmann Denk. Retrieved 23 March 2024.
- ^ a b "Saturn Moons". Carnegie Science. Earth & Planets Laboratory. Retrieved 23 March 2024.
- ^ Grishin, Evgeni (September 2024). "Irregular Fixation II: The orbits of irregular satellites". Monthly Notices of the Royal Astronomical Society. 533 (1): 497–509. arXiv:2407.05123. Bibcode:2024MNRAS.533..497G. doi:10.1093/mnras/stae1752.