{"title":"On the Assessment of Disturbances in the Rotational Dynamics of Small Asteroids During Their Approach to the Earth","authors":"K. S. Lobanova, A. V. Melnikov","doi":"10.1134/S0038094624601348","DOIUrl":null,"url":null,"abstract":"<p>Through numerical experiments, the influence of the angular velocity of proper rotation, rotation axis orientation, and asteroid shape parameters on the magnitude of perturbations in its rotational dynamics during close approaches to the Earth has been studied. The dynamics of three asteroids was considered: (99 942) Apophis, (367 943) Duende and 2012 TC4. It was found that asteroids with relatively slow rotation (period <i>P</i> > 5 h) are characterized by significant disturbances: in the case of Apophis (<i>P</i> ≈ 30 h) when approaching the Earth in 2029, changes in the rotation period can reach tens of hours, and deviations in the orientation of the rotation axis of ten degrees. In the case of Duende (<i>P</i> ≈ 8 h) when approaching the Earth in 2013, the change in <i>P</i> did not exceed several hours, deviations in the orientation of the rotation axis could amount to tens of degrees. For asteroids with rapid rotation (<i>P</i> < 1 h) the disturbances are negligible: in the case of asteroid 2012 TC4 (<i>P</i> ≈ 12 min) during its approach to the Earth in 2017, the changes in <i>P</i> did not exceed 10<sup>–5</sup> min, the deviations of the rotation axis were less than 0.01°. It is shown that for asteroids with slow rotation, errors in determining the parameters of the asteroid’s figure can lead to noticeable inaccuracies in estimating the magnitudes of disturbances. In contrast, the uncertainty in knowing the figure of an asteroid with rapid rotation does not affect the assessment of disturbances in its rotational dynamics. In the case of Apophis, disturbances in the rotational motion during the upcoming approach to the Earth in 2029 can lead to a decrease in the value of the <i>A</i><sub>2</sub> parameter, which characterizes the Yarkovsky effect, to –2.4 × 10<sup>–14</sup> AU/day<sup>2</sup> or to an increase to –3.2 × 10<sup>–14</sup> AU/day<sup>2</sup>. Perturbations in the rotational dynamics of Duende during its approach to the Earth in 2013 and of asteroid 2012 TC4 during its approach to the Earth in 2017 did not have a noticeable effect on their <i>A</i><sub>2</sub> values.</p>","PeriodicalId":778,"journal":{"name":"Solar System Research","volume":"59 1","pages":""},"PeriodicalIF":0.8000,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Solar System Research","FirstCategoryId":"101","ListUrlMain":"https://link.springer.com/article/10.1134/S0038094624601348","RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"ASTRONOMY & ASTROPHYSICS","Score":null,"Total":0}
引用次数: 0
Abstract
Through numerical experiments, the influence of the angular velocity of proper rotation, rotation axis orientation, and asteroid shape parameters on the magnitude of perturbations in its rotational dynamics during close approaches to the Earth has been studied. The dynamics of three asteroids was considered: (99 942) Apophis, (367 943) Duende and 2012 TC4. It was found that asteroids with relatively slow rotation (period P > 5 h) are characterized by significant disturbances: in the case of Apophis (P ≈ 30 h) when approaching the Earth in 2029, changes in the rotation period can reach tens of hours, and deviations in the orientation of the rotation axis of ten degrees. In the case of Duende (P ≈ 8 h) when approaching the Earth in 2013, the change in P did not exceed several hours, deviations in the orientation of the rotation axis could amount to tens of degrees. For asteroids with rapid rotation (P < 1 h) the disturbances are negligible: in the case of asteroid 2012 TC4 (P ≈ 12 min) during its approach to the Earth in 2017, the changes in P did not exceed 10–5 min, the deviations of the rotation axis were less than 0.01°. It is shown that for asteroids with slow rotation, errors in determining the parameters of the asteroid’s figure can lead to noticeable inaccuracies in estimating the magnitudes of disturbances. In contrast, the uncertainty in knowing the figure of an asteroid with rapid rotation does not affect the assessment of disturbances in its rotational dynamics. In the case of Apophis, disturbances in the rotational motion during the upcoming approach to the Earth in 2029 can lead to a decrease in the value of the A2 parameter, which characterizes the Yarkovsky effect, to –2.4 × 10–14 AU/day2 or to an increase to –3.2 × 10–14 AU/day2. Perturbations in the rotational dynamics of Duende during its approach to the Earth in 2013 and of asteroid 2012 TC4 during its approach to the Earth in 2017 did not have a noticeable effect on their A2 values.
期刊介绍：
Solar System Research publishes articles concerning the bodies of the Solar System, i.e., planets and their satellites, asteroids, comets, meteoric substances, and cosmic dust. The articles consider physics, dynamics and composition of these bodies, and techniques of their exploration. The journal addresses the problems of comparative planetology, physics of the planetary atmospheres and interiors, cosmochemistry, as well as planetary plasma environment and heliosphere, specifically those related to solar-planetary interactions. Attention is paid to studies of exoplanets and complex problems of the origin and evolution of planetary systems including the solar system, based on the results of astronomical observations, laboratory studies of meteorites, relevant theoretical approaches and mathematical modeling. Alongside with the original results of experimental and theoretical studies, the journal publishes scientific reviews in the field of planetary exploration, and notes on observational results.
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