🔭 This new map identifies the stars most likely to harbor life

A team of astronomers has just published a detailed catalog of 2,100 stars, considered as potentially hosting planets conducive to life. This census, the most comprehensive to date, focuses on a specific stellar type: K-type dwarfs, often called orange dwarfs. All these stars are located within a radius of 130 light-years around the Solar System.

This study, presented at a conference of the American Astronomical Society, is based on spectroscopic observations conducted with two telescopes located in the northern and southern hemispheres. It provides precise data on the age, temperature, and stability of each star. This information is important for assessing the conditions that could prevail on potential orbiting planets and guiding future searches for biological signatures.

The little-known advantages of orange dwarfs

The targeted stars, called K-type dwarfs or "orange dwarfs," possess very interesting intermediate characteristics. They are slightly less massive, cooler, and less luminous than our Sun, which is a G-type star. However, their abundance in the solar neighborhood is about twice that of stars like our Sun.


Their main advantage lies in their extraordinary longevity. While the Sun will live about 10 billion years on the main sequence, K dwarfs can remain there for 20 to 70 billion years. This extended lifespan offers a considerably larger time window for the emergence and evolution of complex processes such as life.

Finally, their behavior is calmer than that of small red dwarfs. The latter are often subject to violent stellar flares and emit intense ultraviolet radiation, likely to erode planetary atmospheres. Orange dwarfs exhibit more moderate magnetic activity, creating a potentially more stable space environment for orbiting planets.

A complete mapping of our stellar neighborhood

To create this inventory, astronomers used two observatories strategically placed around the globe. The SMARTS telescope in Chile and the Tillinghast Telescope in Arizona, both equipped with high-precision spectrographs, allowed for full sky coverage. This configuration enables the observation of all target stars without any blind spots.

Detailed spectroscopic analysis provided a true identity card for each star. Researchers were able to determine their surface temperature, rotation speed, approximate age, and even their trajectory within the Milky Way. This data helps identify the most mature and calmest stars, ideal candidates for hosting temperate planets.

This catalog now constitutes a fundamental resource for the scientific community. It allows for focusing the observation efforts of major instruments, such as the James Webb Space Telescope, on the most promising systems.