CHEOPS Observations of HD 95338b: Examining Exomoon Potential

In a recent study published on July 25, 2025, researchers utilized the CHaracterizing ExOPlanets Satellite (CHEOPS) to refine transit parameters of the exoplanet HD 95338b and explore the possibility of detecting exomoons in its orbit. The investigation, led by Szilárd Kálmán and a team of international experts, highlights the challenges and methodologies in the ongoing quest to identify celestial bodies that may orbit exoplanets, a task that remains largely unfulfilled despite the growing catalog of known exoplanets.

The research builds on previous observations and methodologies employed by space missions like the Transiting Exoplanet Survey Satellite (TESS) and the Gaia mission. According to Dr. Kálmán, an astronomer at the University of Debrecen, "The intricate dynamics of exoplanetary systems make the search for exomoons particularly complex, necessitating advanced observational techniques and rigorous data analysis."

The study presents a novel approach that combines ground-based spectroscopic data with CHEOPS observations to achieve more precise measurements of the star and planet parameters. This methodology enabled the team to narrow down the uncertainty on the planet-to-star radius ratio by a factor of 10, providing a clearer picture of HD 95338b's characteristics.

Notably, the analysis included a search for potential exomoons in the form of additional transits within the Hill sphere of HD 95338b. The findings indicated that detecting an exomoon with a radius of approximately 0.8 Earth radii (R⊕) would be feasible under the current observational strategies. However, the study also concluded that a moon with a radius of about 0.6 R⊕ could be excluded at a 1σ significance level.

The implications of these findings extend beyond the immediate study of HD 95338b, as the algorithms and methodologies developed can serve as a foundation for future research on other exoplanetary systems, enhancing our understanding of their potential for hosting moons. Dr. A. E. Simon, an astrophysicist from the University of Geneva, emphasized the broader significance, stating, "The search for exomoons is crucial for understanding the formation and evolution of planetary systems, which may have implications for the search for life beyond Earth."

As the pursuit of exomoons continues, the research community remains optimistic. The application of sophisticated observation techniques and collaborative efforts among international space agencies promise to advance our understanding of distant worlds and their potential for supporting life. The CHEOPS mission, in particular, exemplifies the collaborative spirit of modern astrophysics, integrating data from various sources to enhance our knowledge of the cosmos.

In summary, the refined transit parameters of HD 95338b, coupled with the search for exomoons, represent a significant step forward in exoplanetary science, illuminating pathways for future explorations and discoveries within our galaxy. The methodologies developed in this study are expected to contribute to ongoing and future missions aimed at unraveling the mysteries of exoplanets and their moons.