Super-Earths May Be More Common and Distant Than Expected, Study Finds

An international team of astronomers has discovered that "super-Earths"—planets several times the mass of Earth—can orbit their host stars at vast distances, much like gas giants such as Jupiter. This finding, made using the Korea Microlensing Telescope Network (KMTNet), suggests that such planets may be far more prevalent in the universe than previously believed.

The discovery was made possible through gravitational microlensing, a technique that detects planets when a foreground star or planet aligns with a background star, temporarily magnifying the latter's light due to the gravitational distortion of spacetime. By analyzing these brief light variations, scientists can not only detect new planets but also gain insights into planetary formation.

The study estimates that at least one in three star systems may host a super-Earth with an orbital period similar to Jupiter’s. This indicates that distant super-Earths could be a common feature of planetary systems.

To date, over 5,500 exoplanets have been discovered, but only 237 have been confirmed using microlensing due to the rarity of the required alignment events. KMTNet, which operates telescopes in South Africa, Chile, and Australia, has significantly improved detection efficiency by providing continuous monitoring across different time zones.

The research categorizes exoplanets into two main groups: super-Earths and Neptune-like planets, and gas giants like Jupiter and Saturn. This classification sheds light on the varied processes by which planetary systems form.

By comparing theoretical models of planet formation, the team found evidence that planets of different masses may originate through distinct mechanisms—such as gas accretion or gravitational instability. Further long-term observations will be needed to test and refine these theories.

The study has been published in the journal Science.