Researchers Detect Potential Exomoon Signal Around HD 206893 B

A recent study accepted for publication in Astronomy & Astrophysics has brought scientists a step closer to confirming the existence of the first exomoon. An international team of researchers utilized advanced detection methods to investigate a potential exomoon orbiting the gas giant exoplanet HD 206893 B, located approximately 133 light-years from Earth.

The researchers applied a technique known as astrometry, which measures the subtle wobbles in the positions of stars and their orbiting bodies. This method allowed them to identify a secondary object that may be orbiting HD 206893 B. The gas giant itself has a radius and mass of approximately 1.25 and 28 Jupiter masses, respectively, with an orbital period of 25.6 years.

Utilizing the VLTI/GRAVITY instrument, the team measured the wobbles between HD 206893 B and its potential companion, which may have an orbital period of 0.76 years and a mass of around 0.4 Jupiter masses. This discovery adds to the ongoing efforts to locate exomoons, of which none have yet been confirmed.

The challenge in detecting exomoons stems from their relatively small size compared to their parent planets. For instance, while HD 206893 B is estimated to be 28 Jupiter masses, its potential exomoon candidate weighs merely 0.4 Jupiter masses. Previous candidates, such as Kepler-1625 b-i and Kepler-1708 b-i, located approximately 7,500 and 5,500 light-years from Earth, were dismissed in a 2024 study after a re-evaluation of data from the Hubble and Kepler space telescopes.

The scientific community’s interest in exomoons is fueled by the presence of more than 200 moons within our solar system, several of which are prime candidates for astrobiology research. Among them are Jupiter’s Europa and Saturn’s Enceladus and Titan. NASA’s Europa Clipper mission is currently on its way to Europa to investigate its habitability, while the agency is preparing to launch the Dragonfly quadcopter to Titan in 2028. Although no missions are planned to revisit Enceladus, scientists continue to analyze data collected by NASA’s Cassini mission, which discovered plumes at Enceladus’ south pole before ending its mission in 2017.

The search for habitable exomoons is also inspired by popular culture, as exemplified by Pandora from the Avatar film series, which showcases a habitable moon supporting various intelligent beings. As research into exomoon candidates advances, the scientific community eagerly anticipates what new discoveries will emerge in the coming years and decades. The quest for knowledge continues, encouraging astronomers and enthusiasts alike to keep exploring the cosmos.