SCIENTISTS have discovered a new super-Earth with an ‘eccentric’ orbit that swings it in-and-out of its star’s habitable zone.
Nearby exoplanet, HD 20794 d, orbits a star very similar to our Sun – a placement that is necessary for life as we know it.
Located roughly 19.7 light-years away, the exoplanet is a relatively close neighbour of Earth.
An international team of experts from the University of Geneva (UNIGE) and the Swiss research foundation NCCR PlanetS found the exoplanet after analysing nearly two decades worth of data.
They used a new system called YARARA, an algorithm recently developed at UNIGE that can go through data like a fine-tooth comb.
“We analysed the data for years, carefully eliminating sources of contamination,” said Michael Cretignier, co-author of the study and developer of YARARA during his PhD at UNIGE.
The exoplanet’s closeness to Earth makes it easier to study, as its light signals are stronger and unobscured by cosmic noise.
Xavier Dumusque, senior lecturer and astronomy researcher at the UNIGE, said: “HD 20794, around which HD 20794 d orbits, is not an ordinary star.
“Its luminosity and proximity makes it an ideal candidate for future telescopes whose mission will be to observe the atmospheres of exoplanets directly.”
Researchers are already eyeing up the European Southern Observatory’s Extremely Large Telescope, which is under construction in the Chilean Atacama Desert.
HD 20794 d takes 647 days to orbit its star, which is around forty days less than Mars.
Unlike Mars, or Earth, its orbit swings between the inner edge of its star and outside again – which has intrigued researchers.
This type of orbit means any water on the planet would freeze and melt depending on where it is in its orbit.
What is a Super-Earth?
A super-Earth is a title given to an exoplanet based on its size. As Nasa explains:
“Super-Earths – a class of planets unlike any in our solar system – are more massive than Earth yet lighter than ice giants like Neptune and Uranus, and can be made of gas, rock or a combination of both.
“They are between twice the size of Earth and up to 10 times its mass.
“The true nature of these planets remains shrouded in uncertainty because we have nothing like them in our own solar system – and yet, they are common among planets found so far in our galaxy.”
Super-Earths can have a variety of planetary compositions.
They could be water worlds, snowball planets, or even dense gas planets like Neptune.
The first exoplanet – a planet outside of our solar system that orbits its own star – was discovered in 1995 by Michel Mayor and Didier Queloz.
The pair were awarded a Physics Nobel Prize in 2019 for their work.
Over the last nearly 30 years, more than 7,000 exoplanets have been detected.
Yet, life elsewhere in the universe continues to evade researchers.
It’s unclear if HD 20794 d harbours alien life – or if it even has all the building blocks to make life possible in the future.
Its habitability is still being studied by the new Centre for Life in the Universe (CVU), an exoplanet research facility, at UNIGE.
All you need to know about planets in our solar system
Our solar system is made up of nine planets with Earth the third closest to the Sun. But each planet has its own quirks, so find out more about them all...
- How old is Earth? Plus other facts on our planet
- How many moons does Mercury have?
- What colour is Venus?
- How far away is Mars to Earth? And other facts on the red planet
- How big is Jupiter?
- How many moons does Saturn have?
- Does Uranus have rings?
- How many moons does Neptune have?
- How big is Pluto?
- How hot is the Sun?
