Scientists increasingly focus on certain types of exoplanets as promising candidates for hosting life, suggesting some may be even more habitable than Earth. Recent research highlights planets orbiting “K-dwarf” stars—orange-hued stars cooler and longer-lived than the Sun—as potentially ideal environments for complex life.

Iva Vilovic, an astrobiologist at the Leibniz Institute for Astrophysics in Potsdam, Germany, conducted laboratory experiments simulating light from K-dwarf stars. Using garden cress grown under this artificial light, she found the plants grew faster and taller compared to those exposed to simulated sunlight resembling that of the Sun. This indicates that photosynthesis—a critical process supporting life on Earth—could operate efficiently under K-dwarf illumination.

Such findings have increased interest in “superhabitable worlds” orbiting these stars. These planets, often described as “super-Earths,” are roughly 20 to 30 percent larger in diameter and about twice as massive as Earth. Their greater gravity may help retain thicker atmospheres. Positioned at optimal distances from K-dwarfs where liquid water can persist, these planets could provide stable, enduring conditions favorable to the emergence and evolution of complex life.

“The longer lifespan of K-dwarfs compared to our Sun could allow life to develop over extended geological timescales,” Vilovic said. Johanna Teske, a planetary scientist at the Carnegie Institution for Science in Washington, described K-dwarf planets as a “sweet spot” for habitability. She noted that habitable zones around K-dwarfs lie closer to the star than Earth's orbit around the Sun, which also facilitates observation with current telescopes.

Astronomers searching for extraterrestrial biosignatures typically analyze the chemical compositions of exoplanet atmospheres. Instruments such as the James Webb Space Telescope primarily target rocky planets orbiting M-dwarfs—small red stars even cooler than K-dwarfs. However, many such planets detected so far appear barren, often stripped of atmospheres by intense stellar activity.

This contrast has prompted a shift in focus toward K-dwarf systems, where conditions may be milder and more conducive to sustaining life over billions of years. While definitive evidence of extraterrestrial biology remains elusive, ongoing studies of super-Earths around K-dwarf stars offer a promising avenue for identifying worlds that might surpass Earth in their capacity to support diverse and complex life forms.