Gravitational Capture of Asteroids by Gas Drag

Figure 5

Four trajectories of Figure 4(c), all in a non rotating planetocentric reference frame with x pointing to the Vernal point. (a) Trajectory for gas density at 𝑡=−80 years. The asteroid scatters in the gas and goes away. (b) Trajectory for gas density at𝑡=−40years. The asteroid enters in the gas envelope, but the gas is strong and makes the asteroid to collide with the planet. (c) Trajectory for gas density at 𝑡=−25 years. The asteroid enters in the gas envelope in a time that the gas is just strong enough to make the asteroid to reduce its energy and not collide with the planet. After the gas vanishes the capture is permanent. (d) Trajectory for gas density at 𝑡=−18 years. The asteroid has a temporary gravitational capture but the gas is too sparce and the asteroid goes away.