The Experts below are selected from a list of 315 Experts worldwide ranked by ideXlab platform
Wesley C Fraser - One of the best experts on this subject based on the ideXlab platform.
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retention of a primordial cold classical kuiper belt in an instability driven model of solar system formation
The Astrophysical Journal, 2011Co-Authors: Konstantin Batygin, Michael E Brown, Wesley C FraserAbstract:The cold classical population of the Kuiper Belt exhibits a wide variety of unique physical characteristics, which collectively suggest that its dynamical coherence has been maintained throughout the solar system's lifetime. Simultaneously, the retention of the cold population's relatively unexcited orbital state has remained a mystery, especially in the context of a solar system formation model, that is driven by a transient period of instability, where Neptune is temporarily eccentric. Here, we show that the cold belt can survive the instability, and its dynamical structure can be reproduced. We develop a simple analytical model for secular excitation of cold Kuiper Belt objects and show that comparatively fast apsidal Precession and nodal recession of Neptune, during the eccentric phase, are essential for preservation of an unexcited state in the cold classical region. Subsequently, we confirm our results with self-consistent N-body simulations. We further show that contamination of the hot classical and scattered populations by objects of similar nature to that of cold classicals has been instrumental in shaping the vast physical diversity inherent to the Kuiper Belt.
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retention of a primordial cold classical kuiper belt in an instability driven model of solar system formation
arXiv: Earth and Planetary Astrophysics, 2011Co-Authors: Konstantin Batygin, Michael E Brown, Wesley C FraserAbstract:The cold classical population of the Kuiper belt exhibits a wide variety of unique physical characteristics, which collectively suggest that its dynamical coherence has been maintained through out the solar system's lifetime. Simultaneously, the retention of the cold population's relatively unexcited orbital state has remained a mystery, especially in the context of a solar system formation model, that is driven by a transient period of instability, where Neptune is temporarily eccentric. Here, we show that the cold belt can survive the instability, and its dynamical structure can be reproduced. We develop a simple analytical model for secular excitation of cold KBOs and show that comparatively fast apsidal Precession and nodal recession of Neptune, during the eccentric phase, are essential for preservation of an unexcited state in the cold classical region. Subsequently, we confirm our results with self-consistent N-body simulations. We further show that contamination of the hot classical and scattered populations by objects of similar nature to that of cold classicals has been instrumental in shaping the vast physical diversity inherent to the Kuiper belt.
Xing Wei - One of the best experts on this subject based on the ideXlab platform.
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The combined effect of Precession and convection on the dynamo action
The Astrophysical Journal, 2016Co-Authors: Xing WeiAbstract:To understand the generation of the Earth's and planetary magnetic fields, we investigate numerically the combined effect of Precession and convection on the dynamo action in a spherical shell. The convection alone, the Precession alone and the combined effect of convection and Precession are studied at the low Ekman number at which the precessing flow is already unstable. The key result is that although the Precession or convection alone is not strong to support the dynamo action the combined effect of Precession and convection can support the dynamo action because of the resonance of Precessional and convective instabilities. This result may interpret why the geodynamo maintains for such a long history compared to the Martian dynamo.
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Stratified Precessional flow in spherical geometry
Journal of Fluid Mechanics, 2013Co-Authors: Xing Wei, Andreas TilgnerAbstract:We investigate numerically, in spherical geometry, the interaction of stratification with Precession. Both stable stratification and unstable stratification are studied. In the parameter regime we are concerned with, stable stratification suppresses the Precessional instability, whereas unstable stratification and Precession can either stabilize or destabilize each other at different Precession rates.
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stratified Precessional flow in spherical geometry
arXiv: Fluid Dynamics, 2013Co-Authors: Xing Wei, Andreas TilgnerAbstract:We investigate numerically in spherical geometry the interaction of stratification with Precession. Both stable stratification and unstable stratification are studied. In the parameter regime we are concerned with, stable stratification suppresses the Precessional instability, whereas unstable stratification and Precession can either stablise or destablise each other at the different Precession rates.
Andreas Tilgner - One of the best experts on this subject based on the ideXlab platform.
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Stratified Precessional flow in spherical geometry
Journal of Fluid Mechanics, 2013Co-Authors: Xing Wei, Andreas TilgnerAbstract:We investigate numerically, in spherical geometry, the interaction of stratification with Precession. Both stable stratification and unstable stratification are studied. In the parameter regime we are concerned with, stable stratification suppresses the Precessional instability, whereas unstable stratification and Precession can either stabilize or destabilize each other at different Precession rates.
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stratified Precessional flow in spherical geometry
arXiv: Fluid Dynamics, 2013Co-Authors: Xing Wei, Andreas TilgnerAbstract:We investigate numerically in spherical geometry the interaction of stratification with Precession. Both stable stratification and unstable stratification are studied. In the parameter regime we are concerned with, stable stratification suppresses the Precessional instability, whereas unstable stratification and Precession can either stablise or destablise each other at the different Precession rates.
Konstantin Batygin - One of the best experts on this subject based on the ideXlab platform.
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retention of a primordial cold classical kuiper belt in an instability driven model of solar system formation
The Astrophysical Journal, 2011Co-Authors: Konstantin Batygin, Michael E Brown, Wesley C FraserAbstract:The cold classical population of the Kuiper Belt exhibits a wide variety of unique physical characteristics, which collectively suggest that its dynamical coherence has been maintained throughout the solar system's lifetime. Simultaneously, the retention of the cold population's relatively unexcited orbital state has remained a mystery, especially in the context of a solar system formation model, that is driven by a transient period of instability, where Neptune is temporarily eccentric. Here, we show that the cold belt can survive the instability, and its dynamical structure can be reproduced. We develop a simple analytical model for secular excitation of cold Kuiper Belt objects and show that comparatively fast apsidal Precession and nodal recession of Neptune, during the eccentric phase, are essential for preservation of an unexcited state in the cold classical region. Subsequently, we confirm our results with self-consistent N-body simulations. We further show that contamination of the hot classical and scattered populations by objects of similar nature to that of cold classicals has been instrumental in shaping the vast physical diversity inherent to the Kuiper Belt.
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retention of a primordial cold classical kuiper belt in an instability driven model of solar system formation
arXiv: Earth and Planetary Astrophysics, 2011Co-Authors: Konstantin Batygin, Michael E Brown, Wesley C FraserAbstract:The cold classical population of the Kuiper belt exhibits a wide variety of unique physical characteristics, which collectively suggest that its dynamical coherence has been maintained through out the solar system's lifetime. Simultaneously, the retention of the cold population's relatively unexcited orbital state has remained a mystery, especially in the context of a solar system formation model, that is driven by a transient period of instability, where Neptune is temporarily eccentric. Here, we show that the cold belt can survive the instability, and its dynamical structure can be reproduced. We develop a simple analytical model for secular excitation of cold KBOs and show that comparatively fast apsidal Precession and nodal recession of Neptune, during the eccentric phase, are essential for preservation of an unexcited state in the cold classical region. Subsequently, we confirm our results with self-consistent N-body simulations. We further show that contamination of the hot classical and scattered populations by objects of similar nature to that of cold classicals has been instrumental in shaping the vast physical diversity inherent to the Kuiper belt.
Ritam Mallick - One of the best experts on this subject based on the ideXlab platform.
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effect of rotation and magnetic field in the gyroscopic Precession around a neutron star
European Physical Journal C, 2020Co-Authors: Kamal Krishna Nath, Ritam MallickAbstract:General relativistic effects are essential in defining the spacetime around massive astrophysical objects. The effects can be captured using a test gyro. If the gyro rotates at some fixed orbit around the star, then the gyro Precession frequency captures all the general relativistic effects. In this article, we calculate the overall Precession frequency of a test gyro orbiting a rotating neutron star or a rotating magnetar. We find that the gyro Precession frequency diverges as it approaches a black hole, whereas, for a neutron star, it always remains finite. For a rotating neutron star, a prograde motion of the gyro gives a single minimum, whereas a retrograde motion gives a double minimum. We also find that the gyroscope Precession frequency depends on the star’s mass and rotation rate. Depending on the magnetic field configuration, we find that of the Precession frequency of the gyro differs significantly inside the star; however, outside the star, the effect is not very prominent. Also, the gyro Precession frequency depends more significantly on the star’s rotation rate than its magnetic field strength.
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Effect of rotation and magnetic field in the gyroscopic Precession around a neutron star
arXiv: High Energy Astrophysical Phenomena, 2019Co-Authors: Kamal Krishna Nath, Ritam MallickAbstract:We study the overall spin Precession frequency of a test gyroscope around a neutron star. The Precession of the test gyroscope gives the signatures of the general relativistic effects that are present in the region of strong gravity of an NS. Using a numerical code, we find the Precession of the test gyroscope for a rotating and a strongly magnetized neutron star. The magnetic field distribution inside the neutron star is assumed either to be poloidal or toroidal. The overall spin Precession rate is obtained by setting the orbital frequency of the gyroscope to a non-zero value but restricted to a time-like observer. The gyro frequency differs depending on the central object being a black hole or a neutron star. For neutron star, the gyro Precession can even be calculated inside the star. We find that the gyroscope Precession frequency depends on the stars mass, rotation rate, and magnetic field configuration.
