A recent global study indicates that super-Earths, planets larger than Earth but smaller than Neptune, may be more common in the universe than previously believed. Conducted by astronomers from Ohio State University, Harvard, and various institutions in China and Korea, the research used data from the Korea Microlensing Telescope Network (KMTNet), which includes telescopes in South Africa, Chile, and Australia. Using gravitational microlensing, the team discovered that super-Earths can orbit far from their stars, similar to or even wider than Jupiter’s orbit, challenging earlier assumptions that these planets only form close to their stars. A notable find was OGLE-2016-BLG-0007, a planet about twice the size of Earth with an orbit larger than Saturn’s, identified through microlensing, where a planet’s gravity bends light from a distant star. Andrew Gould, a co-author of the study, noted, ‘This study suggests that for every three stars, there may be at least one super-Earth with a wide, Jupiter-like orbit,’ marking a significant shift in our understanding of planetary systems. While smaller planets are known to be more common, this study highlights our limited knowledge of distant planets. Traditional detection methods like transits and radial velocity mainly find planets in close orbits, whereas microlensing allows for the discovery of planets at greater distances. The findings also prompt new questions about planet formation, suggesting that gravitational instability may play a role alongside the previously thought runaway gas accretion process. ‘We don’t yet know which formation process dominates,’ Gould stated, ‘but this adds a new piece.’ Discovering planets via microlensing is uncommon, with only 237 out of more than 5,000 known exoplanets found using this method. However, as technology advances and international collaboration increases, astronomers are optimistic about making more discoveries soon. Co-author Richard Pogge noted, ‘These emerging patterns in planet types are enhancing our understanding of solar system formation and evolution, akin to piecing together the universe’s family tree.’ This research represents an important milestone in the quest for distant planets, including those that might support life.
