YORP effect on the evolution of asteroid spin states

Yan, XiaoRan; Li, Junfeng

doi:10.1360/sspma-2019-0130

Cited by 3 publications

(1 citation statement)

References 24 publications

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“…We assumed the simple and most widely used Lambert scattering law, in which the light is emitted in all directions with an intensity proportional to the cosine of the angle between the light direction and the normal vector of the surface. For concave configurations such as a crater, we should consider the selfheating effect, which arises because some of the photons may be re-absorbed by the nearby shelter, which prevents them from contributing to the effective recoil force (Statler 2009;Yan & Li 2019). The reemission of the obscuring parts, which might make a difference for a concave structure (Rozitis & Green 2013), is ignored in this work for its complexity and will be studied in the future.…”

Section: Self-heatingmentioning

confidence: 99%

The crater-induced YORP effect

Zhou

Zhang

Yan

et al. 2022

A&A

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Context. The Yarkovsky−O'Keefe−Radzievskii−Paddack (YORP) effect plays an important role in the rotational properties and evolution of asteroids. While the YORP effect induced by the macroscopic shape of the asteroid and by the presence of surface boulders has been well studied, no investigation has been performed yet regarding how craters with given properties influence this effect. Aims. We introduce and estimate the crater-induced YORP effect (CYORP), which arises from the concave structure of the crater, to investigate the magnitude of the resulting torques as a function of varying properties of the crater and the asteroid by a semi-analytical method. Methods. By using a simple spherical shape model of the crater and assuming zero thermal inertia, we calculated the total YORP torque due to the crater, which was averaged over the spin and orbital motions of the asteroid, accounting for self-sheltering and self-sheltering effects.Results. The general form of the CYORP torque can be expressed in terms of the crater radius R 0 and the asteroid radius R ast :, where W is an efficiency factor. We find that the typical values of W are about 0.04 and 0.025 for the spin and obliquity component, respectively, which indicates that the CYORP can be comparable to the normal YORP torque when the size of the crater is about one-tenth of the size of the asteroid, or equivalently when the crater/roughness covers one-tenth of the asteroid surface. Although the torque decreases with the crater size R 0 as ∼ R 2 0 , the combined contribution of all small craters can become non-negligible due to their large number when the commonly used power-law crater size distribution is considered. The CYORP torque of small concave structures, usually considered as surface roughness, is essential to the accurate calculation of the complete YORP torque. Under the CYORP effect that is produced by collisions, asteroids go through a random walk in spin rate and obliquity, with a YORP reset timescale typically of 0.4 Myr. This has strong implications for the rotational evolution and orbital evolution of asteroids.Conclusions. Craters and roughness on asteroid surfaces, which correspond to concave structures, can influence the YORP torques and therefore the rotational properties and evolution of asteroids. We suggest that the CYORP effect should be considered in the future investigation of the YORP effect on asteroids.

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Section: Self-heatingmentioning

confidence: 99%

The crater-induced YORP effect

Zhou

Zhang

Yan

et al. 2022

A&A

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Hill stability of coplanar four-body systems with application to the Solar System and extrasolar systems

Liu

Gong

2019

Astrophys Space Sci

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Stability time-scale prediction for main-belt asteroids using neural networks

Liu

Gong

2021

Monthly Notices of the Royal Astronomical Society

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Many asteroids move in the belt between the orbits of Mars and Jupiter under the gravitational attraction of the Sun and planets in the Solar system. If one of these asteroids does not leave the belt during a period, it is considered to be temporarily stable on that time-scale. This paper aims to study the time-scales on which asteroids could stay in the main belt. A simplified situation is studied in which the initial orbital inclinations and the longitudes of the ascending nodes of the asteroids are set to zero. Numerical integration is used to study the temporal stability of the main-belt asteroids. In the integration, the distribution of the instability time for randomly generated particles can be fitted with a function. Thus a reasonable method is presented to choose an integration time-scale based on the percentage of the already unstable particles in relation to all unstable particles. A total of 151 000 particles are generated and then integrated for 8.09 × 106 yr. The integration data are used to train the probabilistic neural networks to predict the stability of particles. A temporal stability map in the a-e plane is obtained from the prediction results of the neural networks.

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YORP effect on the evolution of asteroid spin states

Cited by 3 publications

References 24 publications

The crater-induced YORP effect

The crater-induced YORP effect

Hill stability of coplanar four-body systems with application to the Solar System and extrasolar systems

Stability time-scale prediction for main-belt asteroids using neural networks

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