Can cometary bombardment disrupt synchronous rotation of planetary satellites?

<p>Most close-in planetary satellites are in synchronous rotation, which is usully the stable end-point of tidal despinning. Saturn's moon Hyperion is a notable exception by having a chaotic rotation. Hyperion's dynamical state is a consequence of its high eccentricity and its highly prolate shape (Wisdom et al. 1984). As many binary asteroids also have elongated secondaries, chaotic rotation is expected for moons in eccentric binaries (Cuk & Nesvorny 2010), and a minority of asteroidal secondaries may be in that state (Pravec et al. 2016). The question of the secondary's rotation is importrant for the action of the BYORP effect, which can quickly evolve orbits of synchrnous (but not non-synchronous) secondaries (Cuk & Burns 2005). Here we report preliminary numerical simulations which indicate that in binary systems with a large secondary and significant spin-orbit coupling a different kind of non-synchronous rotation may arise. In this "barrel instability" the secondary slowly rolls along its long axis, while the longest diameter is staying largelly aligned with the primary-secondary line. This behavior &#160;may be more difficult to detect through lightcurves than a fully chaotic rotation, but would likewise shut down BYORP. Unlike fully chaotic rotation, barrel instability can happen even at low eccentricties. In our presentation we will discuss our theoretical results and their implications for the evolution of binary asteroids, such as the Didymos-Dimorphos pair.</p>

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Barrel Instability in Binary Asteroids

The Planetary Science Journal ◽

10.3847/psj/ac3093 ◽

2021 ◽

Vol 2 (6) ◽

pp. 231

Author(s):

Matija Ćuk ◽

Seth A. Jacobson ◽

Kevin J. Walsh

Keyword(s):

Numerical Simulations ◽

Rotational State ◽

Large Set ◽

Binary Asteroids ◽

High Eccentricity ◽

Earth Asteroid ◽

Prolate Shape ◽

Planetary Satellites ◽

Synchronous Rotation ◽

Secondary Line

Abstract Most close-in planetary satellites are in synchronous rotation, which is usually the stable end-point of tidal despinning. Saturn’s moon Hyperion is a notable exception by having a chaotic rotation. Hyperion’s dynamical state is a consequence of its high eccentricity and its highly prolate shape. As many binary asteroids also have elongated secondaries, chaotic rotation is expected for moons in eccentric binaries, and a minority of asteroidal secondaries may be in that state. The question of secondary rotation is also important for the action of the binary Yarkovsky–O’Keefe–Radzievskii–Paddack (BYORP) effect, which can quickly evolve orbits of synchronous (but not nonsynchronous) secondaries. Here we report results of a large set of short numerical simulations which indicate that, apart from synchronous and classic chaotic rotation, close-in irregularly shaped asteroidal secondaries can occupy an additional, intermediate rotational state. In this “barrel instability” the secondary slowly rolls along its long axis, while the longest axis is staying largely aligned with the primary–secondary line. This behavior may be more difficult to detect through lightcurves than a fully chaotic rotation, but would likewise shut down BYORP. We show that the binary’s eccentricity, separation measured in secondary’s radii and the secondary’s shape are all important for determining whether the system settles in synchronous rotation, chaotic tumbling, or barrel instability. We compare our results for synthetic asteroids with known binary pairs to determine which of these behaviors may be present in the near-Earth asteroid binary population.

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A new mechanism of smart jumping robot for lunar or planetary satellites exploration

2017 IEEE Aerospace Conference ◽

10.1109/aero.2017.7943807 ◽

2017 ◽

Cited By ~ 1

Author(s):

Kent Yoshikawa ◽

Masatsugu Otsuki ◽

Takashi Kubota ◽

Takao Maeda ◽

Masataka Ushijima ◽

...

Keyword(s):

Planetary Satellites ◽

Jumping Robot

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On the chaotic rotation of planetary satellites: The Lyapunov spectra and the maximum Lyapunov exponents

Astronomy and Astrophysics ◽

10.1051/0004-6361:20021147 ◽

2002 ◽

Vol 394 (2) ◽

pp. 663-674 ◽

Cited By ~ 34

Author(s):

I. I. Shevchenko ◽

V. V. Kouprianov

Keyword(s):

Lyapunov Exponents ◽

Lyapunov Spectra ◽

Planetary Satellites ◽

Maximum Lyapunov Exponents

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Gravitational instability and the formation of planetary systems of solar-type stars

Keldysh Institute Preprints ◽

10.20948/prepr-2021-15 ◽

2021 ◽

pp. 1-32

Author(s):

Mikhail Semenovich Legkostupov

Keyword(s):

Large Scale ◽

Gravitational Instability ◽

Planetary Systems ◽

Complete Model ◽

Ring Model ◽

Gravitational Instabilities ◽

Planetary Satellites ◽

Solar Type

The fundamental principles of the protoplanetary ring model – the model of formation of planetary systems of stars, which is based on the origin and development of large-scale gravitational instabilities (protoplanetary rings) – are extended to the formation of regular planetary satellites. Based on these principles, a complete model of the formation of planetary systems, including their satellites, (model of gas and dust rings) for solar-type stars is proposed.

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Transmission Error in Helical Timing Belt Drives (Case of a Period of Pulley Pitch)

Journal of Mechanical Design ◽

10.1115/1.1326916 ◽

2000 ◽

Vol 123 (1) ◽

pp. 104-110 ◽

Cited By ~ 11

Author(s):

Masanori Kagotani ◽

Hiroyuki Ueda ◽

Tomio Koyama

Keyword(s):

Helix Angle ◽

Transmission Error ◽

Face Advance ◽

Experimental Conditions ◽

Belt Drives ◽

Noise Characteristics ◽

Synchronous Rotation ◽

Timing Belt ◽

Belt Width ◽

Static Conditions

Helical timing belts have been developed in order to reduce the noise that occurs when conventional timing belts are driven. Helical timing belts are characterized by synchronous rotation. Although several studies have been performed to clarify the noise characteristics and belt life of helical timing belts, the transmission error of these belts remains unclear. In the present study, the transmission error having a period of one pitch of the pulley was investigated both theoretically and experimentally for helical timing belt drives. Experimental conditions were such that the transmission force acts on the helical timing belts under quasi-static conditions and the belt incurs belt climbing at the beginning of meshing and at the end of meshing. Experimental results obtained for the transmission error agreed closely with the computed results. The computed results revealed that helical timing belts can be analyzed as a set of very narrow belts for which the helix angle is zero. The transmission error was found to decrease when the helix angle or the belt width increase within a range defined such that the face advance is less than one belt pitch. In addition, there exists an appropriate installation tension that reduces the transmission error.

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