An international team of scientists, led by Ahmedabad’s Physical Research Laboratory (PRL), has discovered an exoplanet, TOI-6651b, which is five times larger and 60 times heavier than Earth. Situated 690 light-years from the Sun, this sub-Saturn class planet is only the fourth known exoplanet in the Neptunian desert—a region near stars where Neptune-sized planets are rarely found.
Using the high-precision PARAS-2 spectroscope, mounted on a 2.5m telescope at Mount Abu, Rajasthan, researchers identified TOI-6651b, which orbits its Sun-like star in just five days. Its proximity to the star results in intense radiation, causing the gaseous atmosphere to evaporate and leaving behind a metal-rich, rocky core composed of 87% metals, primarily iron. TOI-6651b’s temperature was measured at a scorching 1,500 Kelvin (1,200°C), making it uninhabitable.
The findings, published in Journal of Astronomy and Astrophysics, highlight TOI-6651b as a rare exoplanet in the Neptunian desert. This unique core structure provides valuable insights into the boundary conditions of the Neptunian desert and the evolutionary processes affecting gas giants. The PARAS-2 spectrograph’s advanced resolution was instrumental in detecting TOI-6651b and promises future potential for discovering even smaller exoplanets.
