| Author(s) and Co-Author(s) with Affiliation: Rishikesh Sharma(Astronomy & Astrophysics Division, Physical Research Laboratory, Ahmedabad 380009, India), Sanjay Baliwal(Astronomy & Astrophysics Division, Physical Research Laboratory, Ahmedabad 380009, India), Abhijit Chakraborty(Astronomy & Astrophysics Division, Physical Research Laboratory, Ahmedabad 380009, India), K. J. Nikitha(Astronomy & Astrophysics Division, Physical Research Laboratory, Ahmedabad 380009, India), A. Castro Gonzalez(Centro de Astrobiología, CSIC-INTA, Camino Bajo del Castillo s/n, 28692 Villanueva de la Cañada, Madrid, Spain), Hareesh G. Bhaskar(Technion—Israel Institute of Technology, Department of Physics, Haifa 3200003, Israel), Akanksha Khandelwal(Astronomy & Astrophysics Division, Physical Research Laboratory, Ahmedabad 380009, India), David W. Latham(Center for Astrophysics—Harvard & Smithsonian, 60 Garden Street, Cambridge MA 02138, USA), Allyson Bieryla(Center for Astrophysics—Harvard & Smithsonian, 60 Garden Street, Cambridge MA 02138, USA), Vincent Bourrier(Observatoire Astronomique de l’Université de Genève, Chemin Pegasi 51b, CH-1290 Versoix, Switzerland), Neelam J. S. S. V. Prasad(Astronomy & Astrophysics Division, Physical Research Laboratory, Ahmedabad 380009, India), Kapil K. Bharadwaj(Astronomy & Astrophysics Division, Physical Research Laboratory, Ahmedabad 380009, India), Kevikumar A. Lad(Astronomy & Astrophysics Division, Physical Research Laboratory, Ahmedabad 380009, India), Ashirbad Nayak(Astronomy & Astrophysics Division, Physical Research Laboratory, Ahmedabad 380009, India), Vishal Joshi(Astronomy & Astrophysics Division, Physical Research Laboratory, Ahmedabad 380009, India), Jason D. Eastman(Center for Astrophysics—Harvard & Smithsonian, 60 Garden Street, Cambridge MA 02138, USA) |
| Abstract: We have discovered and characterized a sub-Saturn exoplanet, TOI-6038 A b, based on radial-velocity observations from the PARAS-2 spectrograph combined with photometric data from the Transiting Exoplanet Survey Satellite (TESS). The planet orbits a bright (V = 9.9), metal-rich, late F-type host star with a period of 5.83 days on a nearly circular orbit. Joint modeling of the radial-velocity and photometry data, supported by speckle imaging observations from the PRL 2.5 m telescope, yields a planetary mass of
~78 Earth masses and a radius of ~6.4 Earth radii. Our internal structure modeling indicated a massive core comprising approximately 74% of the planet’s total mass, surrounded by a low-density H/He envelope. TOI-6038A b lies in the transition region between the Neptunian ridge and the savanna and has a bulk density (≈1.6 gm/cm^3) consistent with dense sub-Saturns. Although the host star is part of a wide binary system, first-order estimates suggest that secular perturbations from the companion are unlikely to drive high-eccentricity migration. The bright host star makes TOI-6038A b a promising target for future studies of atmospheric escape and orbital architecture, providing valuable insight into the formation and evolution of close-in sub-Saturns. |
