Amid the constant search for any sign of life other than our own across the Universe, scientist have been increasingly availing themselves of the opportunity to study Earth-sized planets outside the Solar System using swiftly advancing technology to detect biosignatures.
A newly-discovered exoplanet orbiting the star L98-59 has fuelled speculations that it may be able to able to sustain life.
Described in the study as “a warm terrestrial planet with half the mass of Venus transiting a nearby star” as being “flooded by a global ocean” and resembling planets of the inner Solar System, it is one of three initially found in 2019 by the Transiting Exoplanet Survey Satellite (TESS), and later studied using the radial velocity technique with the help of the European Southern Observatory’s Very Large Telescope (ESO’s VLT) in Chile.
Boasting a mass just half that of Venus, this is the lightest exoplanet ever to be measured using the radial velocity technique, which determines size and mass by searching for the “wobble” caused by the planet pulling on its host star, stated the research published in Astronomy & Astrophysics.
As the densities of the planets in the habitable zone of star L98-59 were studied, two were determined to bet mostly dry, yet the third was believed to contain as much as 30 percent water by mass. Since the planets were in the star’s “habitable zone”, it meant that liquid water could potentially persist on their surface.
“The planet in the habitable zone may have an atmosphere that could protect and support life,” said María Rosa Zapatero Osorio, an astronomer at the Centre for Astrobiology in Madrid, Spain, and one of the authors of the study.
Furthermore, the team of astronomers found other, previously unspotted exoplanets in this planetary system at the right distance from the star for liquid water to exist on its surface.
“We have hints of the presence of a terrestrial planet in the habitable zone of this system,” said Olivier Demangeon, a researcher at the Instituto de Astrofísica e Ciências do Espaço, University of Porto in Portugal and a lead author of the study.
In the quest to detect biosignatures on an exoplanet, current telescopes have not been large enough to achieve the required resolution. However, the intriguing system will be observed using the forthcoming NASA/ESA/CSA James Webb Space Telescope (JWST).
Scientists are also staking great hopes on future discovered to be made when ESO’s Extremely Large Telescope (ELT), under construction in the Chilean Atacama Desert, begins observations in 2027.
“We, as a society, have been chasing terrestrial planets since the birth of astronomy and now we are finally getting closer and closer to the detection of a terrestrial planet in the habitable zone of its star, of which we could study the atmosphere,” said Olivier Demangeon.