On the basis of tidal despinning timescale arguments, Peale showed in 1977 that the majority of irregular satellites (with unknown rotation states) are expected to reside close to their initial (fast) rotation states. Here we investigate the problem of the current typical rotation states among all known satellites from a viewpoint of dynamical stability. We explore location of the known planetary satellites on the (ω0,e) stability diagram, where ω0 is an inertial parameter of a satellite and e is its orbital eccentricity. We show that most of the satellites with unknown rotation states cannot rotate synchronously, because no stable synchronous 1:1 spin-orbit state exists for them. They rotate either much faster than synchronously (those tidally unevolved) or, what is much less probable, chaotically (tidally-evolved objects or captured slow rotators).

Original languageEnglish
Pages (from-to)786-794
Number of pages9
JournalIcarus
Volume209
Issue number2
DOIs
StatePublished - 1 Oct 2010

    Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

    Research areas

  • Celestial mechanics, Resonances, Spin-orbit, Rotational dynamics, Satellites, General

ID: 45988062