Rontelm was the third planet in the Aladso star system located in Federation space in the Alpha or the Beta Quadrant. It had a single moon and was the only class M planet in its system. It was most importantly the site of Starbase 12.
Agriculture on Rontelm fed the starbase and all the Starfleet vessels that docked there, while mining supplied its factories.
It had a total surface area of 530,929,130 square kilometers and, with 61% land mass, a total land area of 323,866,760 square kilometers. About 26% of Rontelm's makeup was normal metals, 12% was radioactive elements, 4% was industrial crystals, 2% was special minerals, and it had trace amounts of gemstones. It had a tropical climate, a terrestrial class M atmosphere and a 16 hour day. (FASA RPG module: The Orions: Book of Common Knowledge)