Planets larger than Earth but smaller than Neptune — known as "super-Earths" — may be far more common across the galaxy than previously thought.
The discovery, published in the journal Science, details the identification of a planet twice the size of Earth, orbiting its star at a distance even farther than Saturn’s orbit around the Sun. This planet was detected through the Korea Microlensing Telescope Network (KMTNet), the largest microlensing survey of its kind.
Super-Earths, which fill the size gap between Earth and Neptune, are crucial in understanding planetary systems beyond our own.
This latest study, involving mass measurements of numerous planets relative to their stars, suggests that the diversity of planetary systems in the Milky Way is even greater than previously known.
Using microlensing — a technique where the light from a distant star is magnified by the gravitational field of an intervening planet — researchers were able to find planets that are often located between the orbits of Earth and Saturn. According to the team, this method has now uncovered three times more planets, including many that are significantly smaller than those previously found.
Professor Shude Mao noted that these findings offer important clues about how cold, distant planets form and evolve. With KMTNet’s three strategically placed telescopes in South Africa, Chile, and Australia, scientists have been able to collect a wealth of data on these far-off worlds.
The study also hints at a wide variety of planet sizes existing in other solar systems, including more super-Earths located in the colder, outer regions beyond what would be Earth's orbit.
Jennifer Yee, a researcher involved in the study, pointed out that these findings suggest that planets larger than Earth but smaller than Neptune might be common in other star systems.
Youn Kii Jung, who helps operate KMTNet, added that planetary systems beyond our own may not necessarily resemble the familiar setup of our solar system.
Instead, Jupiter-like orbits could often host different types of planets altogether.