Jan 29, 2025 15:00:00

IAC announces discovery of new 'super-Earth' in habitable zone of Sun-like star system 20 light years away

The Canary Islands Astrophysics Institute (IAC) and

the University of La Laguna (ULL) have confirmed the existence of a new super-Earth planet, HD 20794 d, in the habitable zone around the Sun-like star 82 Eridanus (HD 20794). This discovery is the result of more than 20 years of observations and opens up new possibilities for studying the atmospheres of Earth-like planets.

The IAC confirms the existence of a Super-earth in the habitable zone of a Sun-like Star | Instituto de Astrofísica de Canarias • IAC
https://www.iac.es/en/outreach/news/iac-confirms-existence-super-earth-habitable-zone-sun-star

The discovery was made possible by the analysis of more than 20 years of observational data using two high-performance spectrometers, ESPRESSO and HARPS. A candidate signal was identified in 2022, and its presence was confirmed by two years of additional observations.

The host star, HD 20794, is a Sun-like star, slightly less massive than the Sun, located just 20 light years from Earth. Two super-Earth planets were already discovered in this star system more than a decade ago, and HD 20794 d is the third planet discovered this time.

The main characteristics of HD 20794 d are that it has a mass six times that of Earth and orbits its parent star (HD 20794) every 647 days, 40 days shorter than the orbital period of Mars. The planet is located within the habitable zone at a moderate distance from its star, HD 20794, where liquid water could theoretically exist on its surface.

Unlike planets in the solar system, HD 20794 d's orbit is not circular but elliptical, meaning that its distance from the star varies greatly, moving from the outer edge of the habitable zone to the inner edge, which could lead to significant changes in the planet's climate.

'Indeed, planets like HD 20794 d are very little known. Although HD 20794 d is not a second home for humanity, its location and unusual orbit provide an opportunity to study how the conditions for habitability change over time and what impacts they may have on the planet's atmosphere,' said Alejandro Suárez Mascareño, a researcher at IAC.