Astronomers detect ancient water-rich super-earth twice the size of our planet
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In a breakthrough for exoplanet research, astronomers have identified a water-rich "super-Earth" located approximately 154 light-years from Earth.
The newly validated planet, named TOI-1846 b, is nearly twice the size and over four times the mass of Earth, according to findings published on the arXiv preprint server.
Led by Abderahmane Soubkiou of Morocco's Oukaimeden Observatory, the discovery was made using NASA’s Transiting Exoplanet Survey Satellite (TESS), along with a combination of ground-based photometric data, high-resolution imaging, and spectroscopy.
"We have validated TOI-1846 b using TESS and multicolour ground-based photometric data, high-resolution imaging, and spectroscopic observations," the researchers wrote in the study, as reported by phys.org.
TOI-1846 b has a radius of about 1.792 times that of Earth and is estimated to be 4.4 times more massive. It orbits its host star once every 3.93 days and has an equilibrium temperature of around 568 K.
Researchers believe that the planet is likely to be rich in water, although its exact composition remains uncertain. They emphasised the importance of conducting radial velocity (RV) measurements to confirm its mass and further investigate its structure. “These findings make TOI-1846 b well-suited for mass determination via RV observations. This could be possible with the MAROON-X instrument. (...) We find a TSM [transmission spectroscopy metric] of 47 for TOI-1846 b, which is below the 90 benchmark for small sub-Neptunes,” the authors stated.
The exoplanet’s host star, TOI-1846, is a small and relatively cool star, with a radius just 0.4 times that of the Sun and a mass of about 0.42 solar masses. It has a surface temperature of 3,568 K and is estimated to be 7.2 billion years old, making the system older than our solar system.
This discovery follows a similar one earlier this year, when scientists identified another super-Earth, HD 20794 d, located just 20 light-years away. That planet is six times the mass of Earth and orbits within the habitable zone of a Sun-like star. However, its elliptical orbit raises questions about whether it could support life.
