Thermophysical modeling of the Yarkovsky effect
Abstract
Yarkovsky effect is defined as a radiation pressure force acting on the asteroid's surface. It can alter the orbit of the asteroid over long periods of time. Often the Yarkovsky force is a crucial parameter in determining whether the asteroid will collide with the Earth or not. It causes the spreading of the asteroid families, producing so-called Yarkovsky V-shapes. It also pushes asteroids into resonance with Jupiter, which replenishes the near-Earth asteroid population (Vokrouhlický et al., 2015).
To calculate the Yarkovsky effect on an individual facet of the asteroid, we first solve the one dimensional heat conduction equation using finite difference method. For every element we introduce a finite number of nodes and solve the equation using the first-order difference scheme. The boundary conditions come from the Stefan-Boltzmann equation and illumination of the surface by the Sun. The latter derives from the geometry of the problem, assuming the asteroid is convex. Although we are using our program to calculate the Yarkovsky effect, the same method can be applied to the reconstruction of the thermal inertia of the surface from the infrared observations. For every facet we use the surface temperature to compute the radiation force acting on it. By averaging it over time, we obtain the Yarkovsky effect. In order to verify our results we compare them with the analytic theories for very high and very low thermal inertia (Golubov et al. 2016). At last, the Yarkovsky force of individual facets is integtared over all the surface elements. The convex shapes of the asteroids are taken from the DAMIT database (https://astro.troja.mff.cuni.cz/projects/damit/; see also Ďurech et al. 2010). We are studying the Yarkovskyforce parametrically as a function of thermal inertia, obliquity and the asteroid shape. Our program can calculate the Yarkovsky effect for asteroids with known shapes and thermal properties. By comparing its results to the observational measurements of the Yarkovsky effect, one can determine the density of the asteroid. It is one of the most promising methods to search for metallic asteroids. Acknowledgment. This research was supported by the National Research Foundation of Ukraine (grant N 2020.02/0371"Metallic asteroids: search for parent bodies of iron meteorites, sources of extraterrestrial resources").- Publication:
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Book of Abstracts of the International Churyumov readings “CAMMAC-2020” (November 17-19
- Pub Date:
- December 2020
- Bibcode:
- 2020camm.conf...36K
- Keywords:
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- asteroids