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S. I. Ipatov (NRC/NAS, NASA/GSFC, & Inst. Appl. Math., Russia), J. C. Mather (NASA/GSFC, USA), P. A. Taylor (University of Maryland, USA)
We numerically investigated the migration of dust particles with initial velocities and positions same as those of the numbered asteroids using the Bulirsh-Stoer method of integration and took into account the gravitational influence of 8 planets, radiation pressure, Poynting-Robertson drag and solar wind drag, for values of the ratio between the radiation pressure force and the gravitational force \beta equal to 0.01, 0.05, 0.1, 0.25, and 0.4. For silicate particles such values of \beta correspond to diameters of 40, 9, 4, 1.6, and 1 microns, respectively. For each \beta \ge 0.05 we considered N=500 particles (N=250 for \beta=0.01). In our runs, planets were considered as material points, but, based on orbital elements obtained with a step of \le20 yr, we calculated the mean probability of a collision of a particle with a terrestrial planet during the lifetime of the particle. For smaller particles, the ratio of the number of particles that collided with the Sun to the total number of simulated particles and the probability of collisions of particles with the terrestrial planets are smaller. The probability of a collision of a migrating dust particle with the Earth for \beta=0.01 is greater by a factor of 220 than for \beta=0.4. The mean time ta during which an asteroidal dust particle had a semi-major axis 'a' in intervals with a fixed width is greater for smaller \beta (for the same initial number of particles) at a<3 AU. For \beta \le 0.1 the values of ta are much smaller at a>3.5 AU than at 'a' between 1 and 3 AU, and are usually maximum at 'a' about 2.3 AU. For \beta=0.01 the local maxima of ta corresponding to the 5:6, 6:7, 3:4, and 2:3 resonances with the Earth are greater than the maximum at 2.4 AU. The peaks in distribution of migrating asteroidal dust particles with semi-major axis corresponding to the n/(n+1) resonances with Earth and Venus and the gaps associated with the 1:1 resonances with these planets are more pronounced for larger particles. The spatial density of a simulated dust cloud and its luminosity (as seen from outside) were greater for smaller distance from the Sun. For example, depending on \beta they were greater at 1 AU than at 3 AU by a factor of 2.5-8 and 7-25 (4 and 12-13 at \beta \le 0.05), respectively. For the runs without planets, migration outside 5 AU was smaller. More details can be found in http://arXiv.org/format/astro-ph/0303398. This work was supported by NRC (0158730), NASA (NAG5-10776), INTAS (00-240), and RFBR (01-02-17540).
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Bulletin of the American Astronomical Society, 35 #4
© 2003. The American Astronomical Soceity.