Indian researchers discover new exoplanet TOI-6038A b. Here's all about it

Indian researchers have identified a new exoplanet, TOI-6038A b, which is approximately 78.5 times the mass of Earth and has a radius 6.41 times that of our planet.

Scientists from the Physical Research Laboratory (PRL) in Ahmedabad made this discovery in a wide binary system. The exoplanet, classified as a dense sub-Saturn, completes an orbit around a bright, metal-rich F-type star every 5.83 days in a nearly circular path. Falling within the transition zone between Neptune-like planets and gas giants, TOI-6038A b belongs to a unique category known as "Sub-Saturn," a classification absent in our solar system. This makes it a significant subject for studying planetary formation and evolution.

This marks the second exoplanet detection achieved using the advanced PARAS-2 spectrograph mounted on PRL’s 2.5-meter telescope at Mount Abu Observatory. It is also the fifth exoplanet discovery facilitated by the combined efforts of the PARAS-1 and PARAS-2 spectrographs. India's growing proficiency in astronomical instrumentation is highlighted through PARAS-2, the most precise stabilized radial velocity (RV) spectrograph in Asia. The high-resolution radial velocity data from PARAS-2, combined with speckle imaging from PRL’s telescope, played a crucial role in confirming the planetary nature of the observed transit signal.

With a density of 1.62 g/cm³, TOI-6038A b is considered a highly dense sub-Saturn. Researchers suggest its formation may be linked to processes such as high-eccentricity tidal migration (HEM) or early disk-driven migration. Its host star, TOI-6038A, is part of a binary system along with a K-type companion star, TOI-6038B, situated 3,217 AU away. The influence of this wide binary companion, along with the exoplanet’s density and orbital characteristics, presents intriguing questions about its formation and migration. While gravitational perturbations from the companion star might affect the exoplanet’s orbit, preliminary studies indicate that these interactions alone may not fully explain its close-in position. Notably, only four other sub-Saturn exoplanets have been identified in binary systems.

Initial findings on TOI-6038A b’s internal structure indicate that about 75% of its mass consists of a dense rocky core, while the remaining fraction is composed of a hydrogen-helium envelope. This offers valuable insights into the transition from rocky planets to gas giants. The system’s brightness makes it an ideal candidate for further atmospheric studies and spin-orbit alignment research, potentially refining theories on exoplanet migration. Additionally, investigating possible undetected companions within the system may shed further light on the factors shaping its evolution.