HD 20794 d, a planet with six times Earth's mass, orbits a sun-like star 20 light years away. Its position within the habitable zone suggests conditions that could allow liquid water to exist.
Dr Michael Cretignier first identified the planet in 2022 using data from the HARPS spectrograph in Chile. The signal was faint, making it unclear whether it was a planet or an instrumental artefact.
To verify the finding, researchers examined over two decades of data from HARPS and ESPRESSO, two highly precise instruments in Chile. Advanced processing techniques ruled out alternative explanations, confirming the planet’s existence.
Unlike most planets, HD 20794 d has an elliptical orbit, shifting between the outer and inner edges of the habitable zone. This variation affects its climate, making it uncertain whether the planet could sustain life.
The planet's proximity to Earth makes it a key target for upcoming projects like the Extremely Large Telescope and the Habitable Worlds Observatory. These instruments aim to study exoplanet atmospheres for biosignatures.
HD 20794 d provides a case study for refining techniques used to detect and analyse exoplanets. Its confirmation demonstrates the effectiveness of long-term spectroscopic monitoring.
Scientists plan to investigate the planet’s atmosphere and composition to assess its potential for hosting life. Future observations may determine whether HD 20794 d has conditions suitable for sustaining biological activity.