Abstract Details
| Name: Avinash Salguneswaran Affiliation: Christ University Conference ID: ASI2025_62 Title : Updated Ephemeris of WASP-18 b and Investigation Into the Existence of WASP-18 c Authors and Co-Authors : Avinash S. Nediyedath 1,2,3, Kyle A. Pearson 3,4, Tara Fetherolf 3,5,6, Andre O. Kovacs 3,7, Robert T. Zellem 3,4 Abstract Type : Poster Abstract Category : Sun, Solar System, Exoplanets, and Astrobiology Abstract : We present an updated ephemeris for the exoplanet WASP-18 b and investigate the potential existence of a second planet, WASP-18 c. Utilizing 140 transit light curves from the Transiting Exoplanet Survey Satellite (TESS), Exoplanet Watch, and the Exoplanet Transit Database (ETD), we derived a refined ephemeris for WASP-18 b, resulting in a mid-transit time of 2460298.55709±0.000026 BJDTDB and an orbital period of 0.941452404 ± 1.4 × 10−8 days. This improved ephemeris reduces uncertainty in future transit predictions, which is essential for scheduling space-based observations like JWST and ARIEL. Additionally, we analyzed 67 radial velocity (RV) observations from the CORALIE and HARPS spectrographs to search for periodic signals indicative of an additional planetary body. Our analysis revealed no significant transit timing variations (TTVs) or RV signals supporting the existence of WASP-18 c. The absence of detectable periodic signals in the TTV and RV data suggests that any potential second planet does not produce strong perturbations on WASP-18 b’s orbit within current observational limits. This work enhances the understanding of the WASP-18 system and provides a valuable resource for future observational campaigns. |