Earth-sized exoplanets circle their stars in Earth-like orbits

A new study has revealed that Earth-sized exoplanets orbit their parent stars in the same way that Earth orbits the Sun, maintaining a roughly equidistant circular orbit.

The researchers from MIT and Aarhus University in Denmark report that 74 exoplanets, located hundreds of light-years away, orbit their respective stars in circular patterns, much like the planets of our solar system.

These 74 exoplanets, which orbit 28 stars, are about the size of Earth, and their circular trajectories stand in stark contrast to those of more massive exoplanets, some of which come extremely close to their stars before hurtling far out in highly eccentric, elongated orbits.

Vincent Van Eylen, a visiting graduate student in MIT's Department of Physics, said that for a planet to be habitable, it would have to be about the size of Earth, small and compact enough to be made of rock, not gas and if a small planet also maintained a circular orbit, it would be even more hospitable to life, as it would support a stable climate year-round.

The study is published in the Astrophysical Journal.