This large planet is habitable to most Vorans, but is almost entirely inhospital to Queens—their carapace is deformed and crushed under its own weight in this gravity. Though it's possible to add structural support to the carapace to compensate, it's uncomfortable and largely unnecessary, as a Queen could simply live on the moon Crescent instead.
As a result, Serenity has become one of the few places in the system where the population lives almost entirely without Queens. The population has developed drugs to prevent females from metamorphosing into Queens when they mature, and relies on incubators to create children. Because drones are not needed to take care of the Queens, very few drones live on Serenity, either. Serenity is also far enough away, and has enough atmosphere, that the solar storms have minimal effect on the climate here (`TMP` and `RAD` are increased only by 1). As a result of this, Serenity has become the largest enclave of the Voran Libertine culture anywhere.