The planet was the home of a Federationcolony in the 24th century. By 2366, the colony had a population of eleven thousand. A species of tea native to this planet was cultivated by the colonists and brewed for drinking. The colony lacked interstellar spacecraft.
In that year, the Husnock destroyed both the colony and the planet, killing all save for one colonist. The planet surface was severely scarred. (TNG: "The Survivors")
"RAW-nuh" was the pronunciation for this planet's name from the script pronunciation guide. 
In the script, it was the ninth planet, not the fourth planet, which was the location of the colony.