Scientists have confirmed the discovery of a new planet which is six times as large as the Earth and could host alien life.
The new planet, with a mass six times that of Earth’s, orbits a star similar to our Sun. It has been named HD 20794 d and confirmed by an international team of scientists.
It was originally found two years ago by Dr Michael Cretignier from Oxford University’s physics department and is located in the Eridanus constellation.
Dr Cretignier explained: “With its location in a habitable zone and relatively close proximity to Earth, this planet could play a pivotal role in future missions that will characterise the atmospheres of exoplanets to search for biosignatures indicating potential life.”
He first identified the potential exoplanet signal in 2022 while studying archive data recorded by the HARPS (High Accuracy Radial Velocity Planet Searcher) spectrograph at the La Silla Observatory in Chile. Such data analyses light absorbed and emitted by objects.
The expert spotted periodic shifts in the spectrum of light emitted by the host star, which Oxford University said could have been caused by a nearby planet’s gravitational pull.
At the time of Dr Cretignier’s initial discovery, it was unclear if the signal was caused by a planet, the star or if it was just a technical glitch.
Members from the international team of scientists studied “highly-precise” measurements taken over 20 years by HARPS and the Echelle SPectrograph for Rocky Exoplanet and Stable Spectroscopic Observations (ESPRESSO). The two instruments are among the most advanced in the world for measuring tiny variations in light.
Detailed in a new study published in Astronomy & Astrophysics, the discovery also relied on data from NASA‘s Transiting Exoplanet Survey Satellite (TESS).
Dr Cretignier said scientists worked on the data for years, analysing and eliminating possible sources of contamination to pinpoint the planet’s signal. The discovery was confirmed after the results from HARPS and ESPRESSO were combined.
Dr Cretignier said: “For me, it was naturally a huge joy when we could confirm the planet’s existence. It was also a relief, since the original signal was at the edge of the spectrograph’s detection limit, so it was hard to be completely convinced at that time if the signal was real or not.
“Excitingly, its proximity with us (only 20 light-years) means there is hope for future space missions to obtain an image of it.”
The new planet is in a part of its system believed by experts to allow life, but the scientists have said it is too soon to say if it could do so.
But experts believe HD 20794 d will prove to be an “invaluable” example for future projects aimed at finding signs of life outside our own solar system.
Dr Cretignier said: “While my job mainly consists of finding these unknown worlds, I’m now very enthusiastic to hear what other scientists can tell us about this newly discovered planet, particularly since it is among the closest Earth-analogues we know about and given its peculiar orbit.”
