Chennai, Feb 12 (Reporter) The Scientists of the Physical Research Laboratory (PRL), Ahmedabad, have discovered new exoplanet, a dense sub-Saturn using PARAS-2 Spectrograph at Mt Abu Telescope. In an update on Wednesday, ISRO said the PRL scientists have discovered a new exoplanet, TOI-6038A b, a dense sub-Saturn size with a mass of 78.5 Earth masses and a radius of 6.41 Earth radii in a wide binary system. The planet orbits a bright, metal-rich F-type star every 5.83 days in a circular orbit. "The TOI-6038A b lies in the transition region between Neptune-like and gas giant exoplanets, called as “Sub-Saturn,” a category absent in our solar system, providing a unique opportunity to study planetary formation and evolution", the Space Agency said. This marks the second exoplanet discovery using the state-of-the-art PARAS-2 spectrograph attached to the 2.5-meter telescope at PRL's Mount Abu Observatory at Gurushikhar, Mt. Abu. Furthermore, it is the fifth exoplanet detection using the combined efforts of the PARAS-1 and PARAS-2 spectrographs. It highlights India's growing expertise in advanced astronomical instrumentation, with the PARAS-2 spectrograph being the highest-resolution stabilized radial velocity (RV) spectrograph in Asia. Precise Radial-Velocity data from PARAS-2, which was used to measure the mass of the planet, along with high-spatial resolution speckle imaging from the PRL's 2.5-meter telescope, were thus absolutely crucial in validating the planetary nature of the transit signal and hence the discovery. TOI-6038A b has a high density (1.62 g/cm³), placing it among the dense sub-Saturns believed to form through unique mechanisms such as high-eccentricity tidal migration (HEM) or early disk-driven migration. Its host star, TOI-6038A, is part of a binary system, accompanied by a K-type star, TOI-6038B, located 3217 AU away. This wide binary companion, along with the planet’s density and orbital characteristics, raises intriguing questions about its formation and migration. While the companion could influence the planet's orbit via secular perturbations, initial analyses suggest these effects may not fully explain its close-in orbit. "Notably, this is only the fifth sub-Saturn exoplanet discovered in a binary system", ISRO said. The preliminary analysis of the internal structure of TOI-6038A b is suggestive of a massive rocky core of about 3/4th (0.75) of its total mass and the remaining mass of the H/He envelope. This offers valuable insights into the transition between terrestrial planets and gas giants. The system's brightness makes it an excellent candidate for atmospheric characterization and spin-orbit alignment studies, which could refine theories on exoplanet migration. Additionally, the search for undetected companions in this system may further illuminate the factors driving its evolution...////...