| Authors : | Akanksha Khandelwal, Priyanka Chaturvedi, Abhijit Chakraborty, Rishikesh Sharma,
Eike. W. Guenther, Carina M. Persson, Malcolm Fridlund, Artie P. Hatzes, Neelam J.S.S.V. Prasad,
Massimiliano Esposito, Sireesha Chamarthi, Ashirbad Nayak, Dishendra, Steve B. Howell |
| Abstract : | The detection and characterization of exoplanets (planets orbiting around stars other than the Sun) provide an essential step towards the goal of discovering habitable planets and improving our understanding of the formation and evolution of planetary systems. In this talk, I’ll present in detail the discovery and characterization of such an exoplanet named TOI-1789b. The planet comes under the hot-Jupiter category and was detected using TESS (NASA’s Transiting Exoplanet Survey Satellite mission) photometry followed by ground-based photometry and high-precision radial velocity (RV) observations. The high-precision RV measurements were obtained by combining data from two high-resolution spectrographs: PARAS at Physical Research Laboratory (PRL), India, and TCES at Thüringer Landessternwarte Tautenburg (TLS), Germany. We complemented space-based TESS data with several ground-based transit observations using PRL’s 0.43 m telescope with the Bessel-R filter. Simultaneous fitting of multiple light curves and RV data gives TOI-1789b a mass of M_p=0.70±0.16 M_J, an inflated radius of R_p=1.44+0.24−0.14 R_J, and an orbital period of 3.20866 days. The planet orbits a 9.1 TESS magnitude, slightly evolved (log g∗= 3.943+0.023−0.043) F-type (T_eff =5991 ±55 K) star. It is one of the few nearby evolved stars with a close-in planet and an important addition in improving our understanding of the mechanisms responsible for inflation in hot-Jupiters. The system also provides an opportunity to understand the evolution of planets around stars leaving the main sequence branch.
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