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Lorenzo Iorio - One of the best experts on this subject based on the ideXlab platform.
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Does the Neptunian system of Satellites challenge a gravitational origin for the Pioneer anomaly
Monthly Notices of the Royal Astronomical Society, 2010Co-Authors: Lorenzo IorioAbstract:If the Pioneer anomaly (PA) was a genuine dynamical effect of gravitational origin, it should also affect the orbital motions of the Solar system's bodies moving in the space regions in which the PA manifested itself in its presently known form, i.e. as a constant and uniform acceleration approximately directed towards the Sun with a non-zero magnitude A Pio = (8.74 ± 1.33) × 10 ―10 ms ―2 after 20 au from the Sun. In this paper we preliminarily investigate its effects on the orbital motions of the Neptunian Satellites Triton, Nereid and Proteus, located at about 30 au from the Sun, both analytically and numerically. Extensive observational records covering several orbital revolutions have recently been analysed for them, notably improving the knowledge of their orbits. Both analytical and numerical calculations, limited to the direct, Neptune-Satellite interaction, show that the peak-to-peak amplitudes of the PA-induced radial, transverse and out-of-plane perturbations over one century are up to 300, 600 km, 8 m for Triton, 17 500, 35 000, 800 km for Nereid and 60,120 km, 30 m for Proteus. The corresponding orbital uncertainties obtained from a recent analysis of all the data available for the Satellites considered are, in general, smaller by one-two orders of magnitude, although obtained without modelling a Pioneer-like extra-force. Further investigations based on a reprocessing of the Satellites' real or simulated data with modified equations of motions including an additional Pioneer-type force as well are worth being implemented and may shed further light on this important issue.
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Does the Neptunian system of Satellites challenge a gravitational origin for the Pioneer anomaly?
Monthly Notices of the Royal Astronomical Society, 2010Co-Authors: Lorenzo IorioAbstract:If the Pioneer Anomaly (PA) was a genuine dynamical effect of gravitational origin, it should also affect the orbital motions of the solar system's bodies moving in the space regions in which the PA manifested itself in its presently known form, i.e. as a constant and uniform acceleration approximately directed towards the Sun with a non-zero magnitude APio = (8.74 +/- 1.33) x 10^-10 m s^-2 after 20 au from the Sun. In this paper we preliminarily investigate its effects on the orbital motions of the Neptunian Satellites Triton, Nereid and Proteus, located at about 30 au from the Sun, both analytically and numerically. Extensive observational records covering sev- eral orbital revolutions have recently been analyzed for them, notably improving the knowledge of their orbits. Both analytical and numerical calculations, limited to the direct, Neptune-Satellite interaction, show that the peak-to-peak amplitudes of the PA-induced radial, transverse and out-of-plane perturbations over one century are up to 300 km, 600 km, 8 m for Triton, 17,500 km, 35,000 km, 800 km for Nereid, and 60 km, 120 km, 30 m for Proteus. The corresponding orbital uncertainties ob- tained from a recent analysis of all the data available for the Satellites considered are, in general, smaller by one-two orders of magnitude, although obtained without modeling a Pioneer-like extra-force. Further investigations based on a re-processing of the Satellites' real or simulated data with modified equations of motions including an additional Pioneer-type force as well are worth being implemented and may shed further light on this important issue.Comment: LaTex2e, 9 pages, 3 tables, 3 figures. To appear in Monthly Notices of the Royal Astronomical Society (MNRAS). Latest data from the perihelion precessions of Uranus, Neptune and Pluto added. Confrontation with the Pioneer Anomaly-induced perihelion precessions included
Norman Murray - One of the best experts on this subject based on the ideXlab platform.
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A dynamical history of the inner Neptunian Satellites
Icarus, 1992Co-Authors: Don Banfield, Norman MurrayAbstract:Abstract We examine a scenario involving the capture origin of Triton and infer the probable dynamical history of the Neptune Satellite system. Triton's highly elongated postcapture orbit forced chaotic perturbations of the eccentricities of the original inner Satellites of Neptune. The resulting large eccentricities quickly led to mutual collisions and self-destruction of the inner Satellites, leaving a disk of debris. Thus, Neptune's inner Satellite system reformed on equatorial orbits after Triton's orbital circularization. It is unlikely that these reformed Satellites survived the flux of cometary impactors. Hence, today's Satellites are probably the remnants of parent Satellites destroyed even more recently than Triton's capture. The remaining puzzle is the inclination of 1989N6, at 4.7°. This is probably due to a temporary inclination resonance capture. 1989N6 has passed through ≤35 inclination resonances in its history. The probability of avoiding all of these is ∼24%; we suggest that 1989N6 was temporarily caught in one. The 1989N6-1989N3 12 : 10 resonance has a 2 : 1 secondary resonance that would eject 1989N6 from the primary resonance at an inclination of roughly 4.7°, matching the observations. We have established the following limits for the Q value of Neptune: 12,000 Q N
Don Banfield - One of the best experts on this subject based on the ideXlab platform.
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A dynamical history of the inner Neptunian Satellites
Icarus, 1992Co-Authors: Don Banfield, Norman MurrayAbstract:Abstract We examine a scenario involving the capture origin of Triton and infer the probable dynamical history of the Neptune Satellite system. Triton's highly elongated postcapture orbit forced chaotic perturbations of the eccentricities of the original inner Satellites of Neptune. The resulting large eccentricities quickly led to mutual collisions and self-destruction of the inner Satellites, leaving a disk of debris. Thus, Neptune's inner Satellite system reformed on equatorial orbits after Triton's orbital circularization. It is unlikely that these reformed Satellites survived the flux of cometary impactors. Hence, today's Satellites are probably the remnants of parent Satellites destroyed even more recently than Triton's capture. The remaining puzzle is the inclination of 1989N6, at 4.7°. This is probably due to a temporary inclination resonance capture. 1989N6 has passed through ≤35 inclination resonances in its history. The probability of avoiding all of these is ∼24%; we suggest that 1989N6 was temporarily caught in one. The 1989N6-1989N3 12 : 10 resonance has a 2 : 1 secondary resonance that would eject 1989N6 from the primary resonance at an inclination of roughly 4.7°, matching the observations. We have established the following limits for the Q value of Neptune: 12,000 Q N
Patrick Moore - One of the best experts on this subject based on the ideXlab platform.
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Atlas of Neptune
1994Co-Authors: Garry E. Hunt, Patrick MooreAbstract:Foreword 1. Introduction 2. Neptune in the solar system 3. The discovery of Neptune 4. Pre-discovery observations 5. Early theories of Neptune 6. Neptune before Voyager 7. The Voyager vision Structure of Neptune 8. Magnetosphere of Neptune 9. Rings of Neptune Satellites of Neptune 10. Beyond Neptune 11. Farewell 12. Voyager 2 Appendix: Data for Neptune Satellite Data.
Garry E. Hunt - One of the best experts on this subject based on the ideXlab platform.
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Atlas of Neptune
1994Co-Authors: Garry E. Hunt, Patrick MooreAbstract:Foreword 1. Introduction 2. Neptune in the solar system 3. The discovery of Neptune 4. Pre-discovery observations 5. Early theories of Neptune 6. Neptune before Voyager 7. The Voyager vision Structure of Neptune 8. Magnetosphere of Neptune 9. Rings of Neptune Satellites of Neptune 10. Beyond Neptune 11. Farewell 12. Voyager 2 Appendix: Data for Neptune Satellite Data.