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How do passing stars send some Oort cloud comets toward the inner solar system?

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Illustration showing the eight planets of the solar system in order from the Sun-Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune-depicted to scale by size, with labeled diameters in miles and kilometers. The Sun is partially visible on the left for comparison. — Solar system The planets (in comparative size) in order of distance from the Sun.

The Oort cloud is a vast, spherical reservoir of icy bodies located at extreme distances from the Sun, typically between 20,000 and 50,000 astronomical units (AU) away. Because these objects are so far from the Sun, their orbits are only loosely bound, making them susceptible to external gravitational influences.1

Passing stars—as well as giant interstellar molecular clouds—can exert gravitational perturbations on these icy bodies. When a star passes sufficiently close to the solar system, its gravity can disrupt the orbits of comets within the outer Oort cloud. This gravitational tug alters the comets' trajectories, occasionally shifting them into orbits that carry them inward toward the planetary region of the inner solar system. Once these "new" comets enter the inner solar system, the gravity of the giant planets, particularly Jupiter, further influences their paths, either capturing them into shorter orbital periods or ejecting them from the solar system entirely.12