TY - JOUR
T1 - Tidal origin of the Laplace resonance and the resurfacing of Ganymede
AU - Malhotra, Renu
N1 - Funding Information:
1 thank Peter Goldreich, David Stevensona, nd Stanton Peale tbr usefuld iscussionsI .am also gratefutl o Don Banfielda ndPhilip Nichol-son for helpfulc ommentsT.h is researchw ass upportedby NASA Grant NAGW-1448 and NSF Grant AST-8913664.
PY - 1991/12
Y1 - 1991/12
N2 - I present a new scenario for the tidal origin of the Laplace resonance. The inner three Galilean satellites are supposed to have formed in orbits well away from the 2/1 pair-wise mean motion commensurabilities and the three body Laplace resonance. The dynamics is controlled by the evolution of the 2/1 critical frequencies, ω1 = 2n2 - n1 and ω2 = 2n3 - n2, where n1, n2, n3 are the mean motions of Io, Europa, and Ganymede. I show that the Laplace relation, ω1 = ω2, may have been established from within a previous three body resonance defined by ω1 ω2 ≈ 1 2. The ω1 ω2 ≈ 1 2 resonance would have excited Ganymede's orbital eccentricity to a high value. The attendant enhanced tidal heating in Ganymede during that high eccentricity period provides a possible explanation for the geologically younger surface of Ganymede compared to that of its "twin satellite," Callisto. The extent of orbital evolution required for this scenario is easily accomodated by values of QJ of several times 105.
AB - I present a new scenario for the tidal origin of the Laplace resonance. The inner three Galilean satellites are supposed to have formed in orbits well away from the 2/1 pair-wise mean motion commensurabilities and the three body Laplace resonance. The dynamics is controlled by the evolution of the 2/1 critical frequencies, ω1 = 2n2 - n1 and ω2 = 2n3 - n2, where n1, n2, n3 are the mean motions of Io, Europa, and Ganymede. I show that the Laplace relation, ω1 = ω2, may have been established from within a previous three body resonance defined by ω1 ω2 ≈ 1 2. The ω1 ω2 ≈ 1 2 resonance would have excited Ganymede's orbital eccentricity to a high value. The attendant enhanced tidal heating in Ganymede during that high eccentricity period provides a possible explanation for the geologically younger surface of Ganymede compared to that of its "twin satellite," Callisto. The extent of orbital evolution required for this scenario is easily accomodated by values of QJ of several times 105.
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U2 - 10.1016/0019-1035(91)90237-N
DO - 10.1016/0019-1035(91)90237-N
M3 - Article
AN - SCOPUS:0042523388
VL - 94
SP - 399
EP - 412
JO - Icarus
JF - Icarus
SN - 0019-1035
IS - 2
ER -