The discovery of a potentially habitable 'super-Earth' exoplanet, HD 20794 d, was published in the scientific journal Astronomy & Astrophysics. Located approximately 19.7 light-years away from Earth in the Eridanus constellation, the exoplanet is considered part of our 'nearby neighborhood' on a universal scale, facilitating its study.
Discovered in 2022 by Dr. Michael Cretignier, a postdoctoral research assistant at the University of Oxford, HD 20794 d was identified while he examined archived data from the High Accuracy Radial Velocity Planet Searcher (HARPS) spectrograph at Chile's La Silla Observatory. "It was also a relief, because the original signal was on the edge of what the spectrograph can detect, so it was difficult to be completely sure that the signal was genuine," said Cretignier.
HD 20794 d orbits a G-type star similar to the Sun and takes 647 days to complete one orbit—40 days fewer than Mars. The planet has a mass 6.6 times greater than Earth, making it easier to study due to its visible and strong light signals. Its luminosity and proximity make it an ideal candidate for future telescopes aiming to observe the atmospheres of such celestial objects, emphasized Xavier Dumusque, a researcher at the University of Geneva and co-author of the study.
One of the intriguing aspects of HD 20794 d is its elliptical orbit, which oscillates in and out of the habitable zone. This implies that its habitability would be fluctuating and limited, according to The Independent. The orbital eccentricity of HD 20794 d is 0.4, making its orbit more elongated than any planet in our solar system, Space.com noted. Despite this, researchers are optimistic. "With its location in a habitable zone and relatively close proximity to Earth, HD 20794 d could play a pivotal role in future missions that will characterize the atmospheres of exoplanets to search for biosignatures indicating potential life," according to The Independent.
The presence of liquid water on HD 20794 d is considered a necessary condition for the existence of life as we know it. "If HD 20794 d had water, it would change from the frozen state to liquid, conducive to the appearance of life, during its orbit around its star," stated the University of Geneva. Scientists do not yet know if the planet has water or an atmosphere, two essential elements for life, according to Newsbomb.
"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," Cretignier said.
An international team of researchers confirmed the discovery of HD 20794 d by analyzing precise measurements recorded over two decades by Chile's HARPS and ESPRESSO spectrographs. The team also utilized algorithms developed by the University of Geneva, including YARARA, which was crucial in confirming the planet's existence, according to Space.com.
The article was written with the assistance of a news analysis system.