Science: HD 20794 d/Super-Earth discovery revealing an exoplanet capable of possibly sustaining life

 

HD 20794 d/Super-Earth discovery revealing an exoplanet capable of possibly sustaining life

By: Christopher Little

An international team with the University of Geneva and NCCR PlanetS, has brought a promising planet into the spotlight. For centuries, the question of life on and off earth has been a topic of debate, but modern science has finally found a possible solution. Progress, however, remains slow and fully focused.

Every new discovery, theoretical and observational keeps pushing the boundaries of what is known about our universe. In 1995, the first sighting of a planet orbiting a star besides us took place. This achievement earned Michel Mayor and Didier Queloz of UNIGE the 2019 Nobel Prize in Physics. Today, most scientists agree that nearly every star has its own planetary system.

Astronomers now prioritize finding exoplanets that are easier to study. This led to the detection of HD 20794 d, a super-Earth—a rocky planet larger than our own. It resides in a planetary system with two other planets and orbits a G-type star, much like our sun. Remarkably, this system is a mere 19.7 light-years away, making it one of Earth’s closest cosmic neighbors.

This is crucial. The star's brightness and the planet's distance make it far easier to study than more distant systems. As Xavier Dumusque, Senior Lecturer at UNIGE and co-author of the study, explains: “Its luminosity and proximity make it an ideal candidate for future telescopes aimed at directly observing exoplanetary atmospheres.”

What makes HD 20794 d particularly exciting is its location in the habitable zone of its star. For stars like HD 20794, this zone stretches a distance that can encompass the orbits of both Earth and Mars in our solar system. HD 20794 d completes its orbit in 647 days, but its path makes its orbit swing between the inner and outer edges of this zone. If water exists on this planet, the temperature changes along its orbit could cause water to shift between frozen and liquid states.

The team analyzed our universe relentlessly, eventually uncovering over 20 years of data using cutting-edge instruments developed by UNIGE, helping filter out noise that had long obscured planetary signals. “We spent years refining the data, removing contamination step by step,” said Michael Cretignier, a researcher at Oxford University and YARARA’s developer.

The discovery of HD 20794 d not only expands our understanding of planetary systems but also offers an incredible testing ground for future research. New and upcoming instruments developed during this research will play a pivotal role in finding signs of life besides us in the universe. While there are still many milestones to achieve, this discovery brings us one step closer to finding our place in the cosmos.

As scientists at UNIGE's Center for Life in the Universe (CVU) continue to study the conditions for life on HD 20794 d, one thing is clear: the search for life beyond Earth has entered an exciting new chapter.