Scientists discover new planet with rocky core, 60 times heavier than Earth | Technology News
An international team of scientists led by the Physical Research Laboratory (PRL), Ahmedabad, has discovered an exoplanet outside our solar system that is five times bigger and 60 times heavier than the Earth.
Identified as TOI-6651b, the sub-Saturn class planet was discovered using the 2nd PRL Advanced Radial Velocity Abu Sky Search (PARAS-2) — a high-end spectroscope mounted on PRL’s 2.5m telescope at Mount Abu in Rajasthan.
Located 690 light years away from the Sun, the newest discovered planet is the third most dense sub-Saturn class located at the edge of the Neptunian desert. Sub-Saturn class planets have a size in between that of Neptune and Saturn. The Neptune desert is a region of the known exoplanet population, where planets rotating close to the stars are rare.
“TOI-6651b is located at the edge of the Neptunian desert. It is crucial for understanding the factors that shape the desert boundaries,” said Sanjay Baliwal, lead author and a fifth year PhD student working with Abhijit Chakraborty, PRL scientist and the team lead.
The study, published on Tuesday in the journal Astronomy and Astrophysics, stated that TOI-6651b orbits around its host star, a Sun-like star, in just 5 days. For comparison, Earth takes 365 days to complete one revolution around its host, the Sun. As the planet is revolving dangerously close to its parent star, this area receives strong irradiation from the star itself, which means that the close-by planets will be unable to retain their gaseous atmosphere for long as they evaporate, leaving behind a rocky core, as in this case.
The core of the exoplanet is massive (nearly 87 per cent of the total planet’s mass) composed of rich metals like iron and was found to be rocky whereas the rest mass consisted of a low-density envopole of hydrogen and helium. Furthermore, the exoplanet’s surface temperature was measured at 1,500 degrees Kelvin (about 1,200 degrees Celsius), thus ruling out TOI-6651b from being habitable.
The researchers noted that PARAS-2, deployed on the 2.5m telescope at PRL’s observatory at Gurushikhar in Mount Abu, played a vital role in this discovery. Operating best in the 380 – 690 nanometre band, this fibre-fed spectrograph offers the highest resolution among spectrographs in Asia. It has been designed to discover super-Earth-like worlds.
“Its high resolution allowed us to discover the sub-Saturn exoplanet, which would not have been possible using its predecessor version. Our team is in the process of further refining the instrument so that even smaller planets can be discovered in future,” he said.
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The other three exoplanets discovered were 11 to 12 times larger than Earth and were termed massive gas giants. And notably, TOI-6651b, too, was once upon a time a gas giant but it has transformed over the years to its present state due to some tidal processes, the study noted.
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