| Popis: |
It is thought that many asteroids in orbits close to the Earth have been moved from outer orbits by the Yarkovsky effect. The orbital change is caused by solar heat absorption and surface re-radiation, creating a recoil force on the asteroid that either increases or decreases the tangential orbital velocity depending upon prograde or retrograde asteroid rotation, respectively. Developing the mathematics to analytically calculate this radiated force is suffi ciently complicated that it cannot be done without a number of approximations. Hence, we have taken a numerical approach to obtain more reliable solutions and evaluate the accuracy of published analytic solutions. Our approach uses the multiphysics software COMSOL, incorporating its heat tranfer package and surface-to-surface radiation module to model the Yarkovsky effect on a spherical asteroid model with homogeneous material composition. For the asteroid Bennu the magnetude of theYarkovsky force is estimated to be 0.12 N at an orbital distance of 0.897 AU (perihelion). |
