In
celestial mechanics, the
Lagrangian points (; also
Lagrange points,
L-points, or
libration points) are positions in an
orbital configuration of two large bodies where a small object affected only by
gravity can maintain a stable position relative to the two large bodies. The Lagrange points mark positions where the combined gravitational pull of the two large masses provides precisely the
centripetal force required to
orbit with them. There are five such points, labeled L1 to L5, all in the orbital plane of the two large bodies. The first three are on the line connecting the two large bodies and the last two, L4 and L5, each form an
equilateral triangle with the two large bodies. The two latter points are stable, which implies that objects can orbit around them in a rotating coordinate system tied to the two large bodies.