Issue |
A&A
Volume 682, February 2024
|
|
---|---|---|
Article Number | A93 | |
Number of page(s) | 25 | |
Section | Planets and planetary systems | |
DOI | https://doi.org/10.1051/0004-6361/202348350 | |
Published online | 08 February 2024 |
Secular change in the spin states of asteroids due to radiation and gravitation torques
New detections and updates of the YORP effect
1
Charles University, Faculty of Mathematics and Physics, Institute of Astronomy,
V Holešovičkách 2,
180 00
Prague,
Czech Republic
e-mail: durech@sirrah.troja.mff.cuni.cz
2
Astronomical Institute, Academy of Sciences of the Czech Republic,
Fričova 1,
251 65
Ondřejov,
Czech Republic
3
Institute of Astronomy of V. N. Karazin Kharkiv National University,
Sumska Str. 35,
Kharkiv
61022,
Ukraine
4
Faculty of Physics, Weizmann Institute of Science,
234 Herzl St.,
Rehovot
7610001,
Israel
5
E. Kharadze Georgian National Astrophysical Observatory,
Abastumani, Georgia
6
Institute of Astronomy and NAO, Bulgarian Academy of Sciences,
72 Tsarigradsko Chaussee Blvd.,
1784
Sofia,
Bulgaria
7
Blue Mountains Observatory,
94 Rawson Pde.
Leura, NSW
2780,
Australia
8
Samtskhe-Javakheti State University,
Rustaveli Street 113,
Akhaltsikhe
0080,
Georgia
9
Institute for Astronomy, University of Edinburgh,
Royal Observatory,
Edinburgh,
EH9 3HJ,
UK
10
Astronomy Research Center, Research Institute of Basic Sciences, Seoul National University,
1 Gwanak-ro, Gwanak-gu,
Seoul
08826,
Korea
11
Modra Observatory, Department of Astronomy, Physics of the Earth, and Meteorology, FMPI UK,
Bratislava
84248,
Slovakia
12
Astronomical Observatory Institute, Faculty of Physics, Adam Mickiewicz University,
Słoneczna 36,
60-286
Poznań,
Poland
13
Crimean Astrophysical Observatory,
Simeiz,
Crimea
14
Université Côte d’Azur, Observatoire de la Côte d’Azur, CNRS, Laboratoire Lagrange,
CS 34229,
06304
Nice Cedex,
France
15
Ulugh Beg Astronomical Institute,
Astronomicheskaya Str. 33,
Tashkent
100052,
Uzbekistan
16
Carl Sagan Center at the SETI Institute,
189 Bernardo Av.,
Mountain View,
CA
94043,
USA
17
Sugarloaf Mountain Observatory,
South Deerfield,
MA
01373,
USA
Received:
23
October
2023
Accepted:
24
November
2023
Context. The rotation state of small asteroids is affected in the long term by perturbing torques of gravitational and radiative origin (the YORP effect). The former can be detected by a change in the spin-axis orientation in the inertial space; the latter manifests itself by a quadratic increase in the rotation phase.
Aims. Direct observational evidence of the YORP effect is the primary goal of our work. This includes both the YORP detection for new objects and an improvement in the accuracy of previously known detections.
Methods. We carried out photometric observations of five near-Earth asteroids: (1862) Apollo, (2100) Ra-Shalom, (85989) 1999 JD6, (138852) 2000 WN10, and (161989) Cacus. Then we applied the light-curve inversion method to all available data to determine the spin state and a convex shape model for each of the five studied asteroids. The YORP effect was modeled as a linear change of the rotation frequency υ ≡ dω/dt. In the case of (2100) Ra-Shalom, the analysis required that the spin-axis precession due to the solar gravitational torque also be included.
Results. We obtained two new detections of the YORP effect: (i) υ = (2.9 ± 2.0) × 10−9 rad d−2 for (2100) Ra-Shalom, and (ii) υ = (5.5 ± 0.7) × 10−8 rad d−2 for (138852) 2000 WN10. The analysis of Ra-Shalom also reveals a precession of the spin axis with a precession constant α ~ 3000″ yr−1. This is the first such detection from Earth-bound photometric data. For the other two asteroids, we improved the accuracy of the previously reported YORP detection: (i) υ = (4.94 ± 0.09) × 10−8 rad d−2 for (1862) Apollo, and (ii) υ = (1.86 ± 0.09) × 10−8 rad d−2 for (161989) Cacus. With this value, Apollo has the most precisely determined YORP effect so far. Despite the recent report of a detected YORP effect for (85989) 1999 JD6, we show that the model without YORP cannot be rejected statistically. Therefore, the detection of the YORP effect for this asteroid requires future observations. In several of our targets, the currently available observations do not provide enough constraints on the shape model (even at large scales) to compute the theoretical YORP effect with sufficient precision. Nevertheless, the interpretation of the detected signal as the YORP effect is fairly plausible. The spin-axis precession constant of Ra-Shalom determined from observations matches the theoretically expected value.
Conclusions. The total number of asteroids with a YORP detection has increased to 12. In all cases, the rotation frequency increases in time. The analysis of a rich photometric data set of irregularly shaped asteroids may require inclusion of spin-axis precession in future studies.
Key words: methods: data analysis / techniques: photometric / minor planets, asteroids: general
© The Authors 2024
Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
This article is published in open access under the Subscribe to Open model. Subscribe to A&A to support open access publication.
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.