Polydeuces

Polydeuces, or Saturn XXXIV, is a small natural satellite of Saturn that is co-orbital with the moon Dione and librates around its trailing Lagrangian point (L5). Its diameter is estimated to be 2–3 km. It is pronounced /ˌpɒlɪˈdjuːsiːz/ POL-i-DEW-seez; Greek : Πολυδεύκης. Dione's other co-orbital moon is Helene, which is bigger and located at the leading L4 point.

Polydeuces was discovered by the Cassini Imaging Team on October 24, 2004, in images taken on October 21, 2004, and given the temporary designation S/2004 S 5. Subsequent searches of earlier Cassini imaging showed it in images as far back as April 9, 2004. Of the four known Lagrangian co-orbitals in the Saturn system ('trojan moon'), Polydeuces wanders the farthest from its Lagrangian point: its distance behind Dione varies from 33.9° to 91.4° with a period of 790.931 days (for comparison, L5 trails Dione by 60°). Polydeuces's libration is large enough that it takes on some qualities of a tadpole orbit, as evidenced by the clear asymmetry between excursions towards and away from Dione. In the course of one such cycle, Polydeuces's orbital radius also varies by about ± 7660 km with respect to Dione's.

The name Polydeuces was approved by the IAU Working Group on Planetary System Nomenclature on January 21, 2005. In Greek mythology, Polydeuces is another name for Pollux, twin brother of Castor , son of Zeus and Leda.

Due to gravitational interactions with Dione, its surface is in hydrostatic equilibrium but not its interior, similar to Methone being in hydrostatic equilibrium due to interactions with Mimas.

Polydeuces is a small moon was physically surveyed during the Greater Solar System Survey Project (Phase IV) which included a detailed survey of all the smaller Saturn and Jupiter moons. (2115 - 2121 ) In 2117 Polydeuces was visited by the UE Leibnitz. The moon was claimed by DGGS Corp. and is utilized as an administrative center.

Discovered by    Cassini Imaging Science Team Discovery date    October 24, 2004 Designations Pronunciation    /ˌpɒlɪˈdjuːsiːz/ POL-i-DEW-seez Alternative names Saturn XXXIV S/2004 S5 Orbital characteristics Semi-major axis 377,396 km [a] Eccentricity    0.0192 Orbital period 2.736915 d [a] Inclination    0.1774 ± 0.0015° Satellite of    Saturn Physical characteristics Dimensions    3 × 2.5 × 2 km[2] Mean radius 1.3 ± 0.4 km[2] Mass    1–5 ×1013 kg [b] Rotation period : synchronous