SP-345 Evolution of the Solar
System
FIGURE 13.4.1-Planetesimal orbits in a
rotating coordinate system x,y, in Earth radii, centered on the Earth
(according to Dole). Small bodies (planetesimals) which originally
move in circular orbits around the Sun with orbital radii greater
than 1 AU will gradually be overtaken by the Earth. In a rotating
coordinate system which fixes the Earth at the origin and the Sun on
the abscissa to the left at a distance of 1 AU (thus assuming the
Earth has a circular orbit), the particles will approach the Earth
and will move in the complicated trajectories depicted in the figure.
If their heliocentric orbital radii fall within seven ranges of
values ("bands") all very close to the dashed line, they will hit the
Earth. Otherwise, they will depart from the neighborhood of the Earth
and return to heliocentric (but noncircular) orbits. Seven similar
bands exist for particles with initial orbital radii less than 1 AU.
(From Dole, 1962.)
- Back -