141 Lumen is a dark, large rocky asteroid 135 km in diameter (about the size of the island of Puerto Rico) near the inner edge of the Main belt within the Eunomia family of asteroids. It is not, however, physically related to the group.

It was discovered on January 13, 1875 by the brothers Paul Henry and Prosper Henry, but Paul is the one who was given the credit for this discovery. It is named after , a book by the astronomer Camille Flammarion.