Onsen Wakusei

is a japanese manga series written by Tsuyoshi Kakubayashi and illustrated by Nobuyuki Takagi. It began serialisation in the April 2009 issue of Manga Time Kirara Forward.

The series was released under 1 volume in September 2009.

Synopsis
In a certain star system, there is a small planet called the Onsen Planet. The entire surface is covered in hot springs, and the ones who manage them are the four Santa Monica siblings.

(Source: MU)