Gravity Assist and Scattering off AGB Stars off Molecular Clouds
Ahmad Hashem Abdelhadi
DOI : 10.3844/ajassp.2009.784.787
American Journal of Applied Sciences
Volume 6, Issue 4
The scattering of stellar orbits by galactic molecular clouds is studied in hope of explaining isotopic peculiarities of presolar grains from Asymptotic Giant Branch (AGB) stars. Silicon isotopic anomalies found in the mainstream Silicon Carbide (SiC) grains are observed to have heavy isotopes enriched. To explain the isotopic heaviness I propose that AGB stars that formed in the interior region of the galaxy, with metallicity higher than solar, change their orbits during close encounters with molecular clouds. The AGB stars give up their SiC grains in winds deposited in the solar neighborhood prior to the birth of the Sun. I model the dynamics by superposing on a standard axisymmetric galactic potential the discrete potentials of thousands of molecular clouds moving in constant circular orbits. Gravity assist occurs when a star scattered into a crossing orbit by one cloud experiences forward scattering from a second cloud.
© 2009 Ahmad Hashem Abdelhadi. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.