Possible Volcanic Moon Detected 635 Light-Years Away
The existence of exomoons (moons around planets outside our solar system) has long been theorized, but their detection has remained elusive due to their small size and faintness. A new NASA-led study, however, suggests that a potential exomoon may be orbiting the exoplanet WASP-49 b, a gas giant located 635 light-years from Earth. The possible exomoon is believed to be rocky and volcanically active, similar to Jupiter’s moon Io.
The study centers on a sodium cloud near WASP-49 b that was discovered in 2017, and which shares characteristics with the gas emissions seen around Io. The scientists tracked the cloud’s motion and the data strongly indicates the presence of a separate orbiting body — an exomoon — as the source.
Further observations are needed to confirm the existence of this potential exomoon. If WASP-49 b indeed hosts a moon similar in size to that of Earth, the exomoon may face a violent fate: Gravitational forces from the exoplanet could eventually cause it to disintegrate.
Credits: NASA/JPL-Caltech
Transcript
A rocky, volcanic moon could be orbiting a planet more than 600 light-years from Earth.
Exomoons, or moons around planets outside our solar system, are likely too small to see directly. But astronomers think volcanic exomoons could make themselves known by creating massive clouds of volcanic gas.
A new study looked at a large sodium cloud discovered in 2017 near the exoplanet WASP-49 b.
Scientists found evidence that the cloud is not produced by the planet or the star it orbits. Instead, the motion of the cloud suggests it originated from another object — possibly a volcanic exomoon.
To get to this conclusion, researchers used a telescope on Earth to observe the silhouettes of the cloud and the exoplanet as they passed in front of the star. In one observation, the researchers saw the sodium cloud moving faster than the planet and away from Earth. If the cloud was coming from the exoplanet, the scientists would expect it to move toward Earth. They think this means the cloud was coming from a different source, like an exomoon.
Jupiter’s moon Io also spews a volcanic cloud into space. It pumps sodium, sulfur, and other gases, creating a massive cloud a thousand times wider than Jupiter.
Io has volcanoes because Jupiter’s gravity squeezes the moon’s interior, heating it. Scientists think WASP-49 b’s gravitational squeezing is likely even more intense and may eventually cause its exomoon to disintegrate. While more observations are needed to confirm the existence of this exomoon, what researchers have found is promising.