Study Reveals Abundance of Earth-like Planets Around Low-mass Stars

In a groundbreaking study led by astronomers from Heidelberg University, researchers have discovered that low-mass stars frequently host Earth-like planets, uncovering new possibilities for extraterrestrial life within our cosmic neighborhood. The findings, published in the journal "Astronomy & Astrophysics" on June 28, 2025, are based on data from the CARMENES project, which employed the CARMENES spectrograph system at the Calar Alto Observatory in Spain to analyze the characteristics of planets orbiting M-dwarfs, stars with mass significantly lower than our Sun.

The CARMENES project, which stands for Calar Alto Legacy Exoplanet Survey, focuses on studying near-infrared spectra to detect the minuscule wobbles in low-mass stars caused by orbiting planets. From a catalog of 2,200 M-dwarfs, the research team, which included international collaborators from Bulgaria, Germany, India, Norway, Spain, and the USA, selected 15 stars for their analysis. They successfully identified four new exoplanets, with the largest being 14 times the mass of Earth and completing its orbit in approximately 3.3 years. The other newly discovered planets have masses ranging from 1.03 to 1.52 Earth masses and orbital periods from 1.43 to 5.45 days.

Dr. Adrian Kaminski, lead author of the study and a researcher at the Königstuhl Observatory, emphasized the significance of the findings, stating, "It is quite remarkable how often small planets occur around very low-mass stars." The statistical analysis indicates that stars with masses below 0.16 solar masses typically host about two planets with masses under three times that of Earth. This trend suggests that low-mass stars are more conducive to forming smaller, rocky planets in close orbits.

The research highlights that among approximately 5,000 known exoplanets in different solar systems, none are a perfect analogue of Earth in terms of mass, radius, surface temperature, and stellar type. However, the newly identified planets meet several key criteria for habitability. According to Prof. Dr. Andreas Quirrenbach, director of the Königstuhl Observatory, "Small, rocky planets in the so-called habitable zone—where liquid water can exist—are potential candidates for hosting life. Since M-dwarfs are abundant and have stable energy output over billions of years, they could create conditions favorable for the development of life."

This study not only sheds light on the prevalence of Earth-like planets around low-mass stars but also provides valuable insights for future exoplanet exploration. As research in this field continues to advance, understanding the potential for habitability in these systems may lead to significant discoveries about life beyond our planet.

The CARMENES project is funded by several organizations, including the Spanish Ministry of Science, the European Union, the Bulgarian National Science Fund, and the German Research Foundation. The implications of these findings could guide future missions aimed at discovering habitable worlds, making the search for extraterrestrial life more promising than ever before.