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Discovery of a north‐south asymmetry in Saturn's radio rotation period
Author(s) -
Gurnett D. A.,
Lecacheux A.,
Kurth W. S.,
Persoon A. M.,
Groene J. B.,
Lamy L.,
Zarka P.,
Carbary J. F.
Publication year - 2009
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2009gl039621
Subject(s) - rotation period , saturn , magnetosphere , physics , rotation (mathematics) , asymmetry , astronomy , period (music) , wavelength , angular momentum , planet , magnetosphere of saturn , astrophysics , magnetic field , magnetopause , stars , optics , geometry , mathematics , quantum mechanics , acoustics
For many years it has been known that Saturn emits intense radio emissions at kilometer wavelengths and that this radiation is modulated by the rotation of the planet at a rate that varies by up to one percent on a time scale of years. Recent radio observations from the Cassini spacecraft have revealed the appearance of a second component, with a rotation period of about 10.6 hours, significantly less than the period of the previously known component, which is currently about 10.8 hours. In this paper we show that the first component originates from the southern auroral region, and that the second component originates from the northern auroral region. This north‐south asymmetry in the rotation period has potentially important implications on how angular momentum is transferred from the interior to the magnetosphere.