Some girl in England first suggested the name for the planet. That the first two letters were the initials of Percival Lowell, who started the search for the ninth planet, helped...the actual discoverer, Clyde Tombaugh, didn't get a lot of attention at first...just a farm boy from Kansas, not a member of one of the elite families of Boston.
Interesting.
Lowell left money for the search for the ninth planet in his will. His widow contested the will, but when the search succeeded she suggested the name Lowell.
There was precedent. Herschel wanted to call Uranus the Georgian Star after his patron, King George. The French favored the name Herschel. Uranus is the masculine form of the name of Urania, the muse of Astronomy.
Galileo similarly named what are today called the Galilean moons the Medician Stars after his patron.
There was considerable controversy over the name of Neptune. It was named after the sea god because of its blue color. Many in France wanted to name it Le Verrier, after the French mathematical astronomer who had accurately predicted the location where Galle discovered it after a brief search. Actually, Galle’s assistant, Heinrich Louis d’Arrest, did most of the work of reducing Le Verrier’s orbit to pointing coordinates and finding the correct and updated star charts unavailable to other observatories, and deserves equal credit.
Astronomer Royal George Biddle Airey took considerable blame for allowing the French to win the race to find Neptune. The young British Astronomer John Couch Adams had undertaken calculations similar to Le Verrier’s, and personally called on Airey twice, without apparent result. In fact, Airey had delegated the search to the Cambridge Observatory. (Adams and Airey had both been “first wranglers” - mathematics first place graduates.) Airey and the Royal Greenwich Observatory was in charge of producing the Nautical Almanac, as well as tables of Magnetic declination and other information useful to Admiralty who funded the RGO. The RGO was a production facility, not a scientific research facility.
After the discovery of Neptune, the Americans got into the act, claiming that the discovery was more luck than brilliant inspiration. The orbit of Neptune was allegedly inferred from its influence on the orbit of Uranus. The inverse perturbation problem is maddeningly difficult, especially in the days before electronic computers. To reduce the number of degrees of freedom, to limit the number of parameters that needed to be determined, both Adams and Le Verrier had assumed that Bode’s Law was approximately correct. In order to fit the observed perturbations, both Adams and Le Verrier had to assign large eccentricity to the orbit of the unknow planet. In fact, Bode’s Law was not valid, and Neptune’s orbit is almost perfectly circular, with only a small eccentricity. The Americans, correctly, attributed the discover more to luck, and the fact that the form of the perturbation would quite logically to assume that a large planet was in the trail of Neptune at the time of discover.
Percival Lowell was an enthusiastic votary of Urania, but gifted with money than talent. He had tried his hand at inferring the orbit of a trans-Neptunian planet based on irregularities in the orbit of Neptune, but without the skill of either an Adams or a Le Verrier. He did have resources neither of them had, his own observatory and staff, and the blink comparator. Fortunately for his reputation, his staff included the dedicated Clyde Tombaugh, whose dogged persistence paid off.