A circumstellar disk is a mixture of gas and dust around a newly forming star. The disk accompanies almost most, if not all, sun-like star formation processes, and planets commonly form in this disk. The disk can also be referred to as a protoplanetary disk because the solid particles inside the disk collide and stick together and grow into planetesimals, which then crash into each other eventually accumulating enough mass to be stabilized as planets. The circular protoplanetary disk, that the FN Tau researchers found, is thick, compact and has a radius 260 times the Earth-Sun distance. Also, it is rather featureless, and does not have any anomalies or asymmetries, such as rings, spirals, or arms.
Because it surrounds a smaller star, the disk about FN Tau is believed to likely contain Earth-like planets. The best-fit model used during this study also showed that the lightweight disk around FN Tau could only produce Earth-like planets. The planetary system formation theory also predicted that the disk is able to form planets lighter than the Earth within 30 astronomical units (AU), the distance where we find planets in our Solar System. For the future, astronomers are hopeful of using Subaru's newest technologies for resolving the detailed structure of the disk to analyze the size and composition of the dust, culminating in the first image of a terrestrial planet near FN Tau.