He was detected and punished.
Peirce gained great fame in the scientific world by his controversy with Leverrier.

Leverrier, as is well known, discovered some perturbations in the movement of the planet Herschel, now more commonly called Uranus, which were not accounted for by known conditions.

From that he reasoned that there must be another planet in the neighborhood and, on turning his glass to the point where his calculations told him the disturbing body must be, he discovered the planet sometimes called by his name and sometimes called Neptune.

This discovery created a great sensation and a burst of admiration for the fortunate discoverer.

Peirce maintained the astounding proposition that there was an error in Leverrier's calculations, and that the discovery was a fortunate accident.