1. Institute of Astronomy, Charles University, Holeovickách 2, 18000 Prague, Czech Republic
2. Dipartimento di Astronomia, Università da Trieste, Trieste, Italy

Correspondence to: Correspondence and requests for materials should be addressed to D.V. (e-mail: Email: vokrouhl@mbox.cesnet.cz).

Abstract

Almost all meteorites come from asteroids, but identifying their specific parent bodies, and modelling their transport to the Earth, has proved to be difficult^{1, 2}. The usual model^{1, 3, 4} of delivery through orbital resonances with the major planets^{5, 6} has recently been shown^{7, 8, 9, 10} to deplete the supply of meteorites much too rapidly to explain either the observed flux at the Earth, or the length of time the meteorites have spent in space (as measured by cosmic-ray exposure ages). Independently, it has been found that a force arising from anisotropically emitted thermal radiation from asteroidal fragments (the 'Yarkovsky effect') influences the fragments' orbits in important ways^{11, 12, 13, 14}. Here we report the results of a detailed model for the transport of meteorites to the Earth, which includes the Yarkovsky effect and collisional evolution of the asteroidal fragments. We find that the Yarkovsky effect significantly increases the efficiency of the delivery of meteorites to the Earth, while at the same time allowing a much wider range of asteroids to contribute to the flux of meteorites. Our model also reproduces the observed distribution^{15, 16} of cosmic-ray exposure ages of stony meteorites.

1. Institute of Astronomy, Charles University, Holeovickách 2, 18000 Prague, Czech Republic
2. Dipartimento di Astronomia, Università da Trieste, Trieste, Italy

Correspondence to: Correspondence and requests for materials should be addressed to D.V. (e-mail: Email: vokrouhl@mbox.cesnet.cz).