A tiny star just 12 light-years away may host two Earth-sized planets in the habitable zone.
Key Takeaways:
- Scientists have identified two potentially habitable, Earth-sized planets orbiting the nearby Teegarden’s star.
- These planets, Teegarden’s star b and c, are close enough for detailed future observations.
- The host star is extremely old and unusually calm, increasing the chances for stable conditions.
- The planets were detected using over 200 measurements from the CARMENES instrument over three years.
- While further confirmation is needed, astronomers are confident these planets truly exist.
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Astronomers have discovered two Earth-sized planets orbiting Teegarden’s star, a dim, ultra-cool red dwarf just 12 light-years away. The planets, identified as Teegarden’s star b and c, are in a zone where liquid water could potentially exist, raising hopes for the presence of life. The findings, reported in Astronomy & Astrophysics, are the result of years of precise observations.
An Ancient, Quiet Star with Potentially Habitable Planets
Teegarden’s star was first detected in 2003, despite being relatively close to Earth. Weighing just 9% of the Sun’s mass, it belongs to the ultra-cool M dwarf class, similar to the TRAPPIST-1 system. However, it is much closer to us than TRAPPIST-1, making it a prime target for further study.
The planets were detected using the CARMENES instrument at Spain’s Calar Alto Observatory, which observed the star for three years. More than 200 measurements revealed periodic “wobbles,” indicating the gravitational pull of orbiting planets. The data suggest Teegarden’s star b orbits its star every 4.9 Earth days, while Teegarden’s star c completes an orbit in 11.4 days. Both planets are about 1.1 times the mass of Earth, making them remarkably similar to our home planet.
One of the most intriguing aspects of this discovery is the star’s behavior. Unlike many red dwarfs, which frequently erupt in violent flares that could strip planets of their atmospheres, Teegarden’s star is unusually quiet. This could improve the chances of habitability for its planets.
The Road Ahead for Confirmation and Exploration
Before confirming the planets as truly habitable, astronomers need to rule out other explanations for the detected signals. While planetary signals can sometimes be mimicked by stellar activity, Teegarden’s star appears so stable that scientists are confident in their findings.
Lauren Weiss, an astronomer at the University of Hawaii, agrees that these are “very plausible-looking planet candidates,” though she notes that uncertainties remain regarding the star’s rotation. However, even if the orbital periods are slightly off, the planets are still real, and follow-up observations with next-generation telescopes could provide more details.
Because of the system’s proximity, it will be a key target for future missions searching for biosignatures—chemical signs of life. Whether these planets truly harbor life remains to be seen, but their discovery marks an exciting step in the search for habitable worlds beyond our solar system.
