Home
Science
Science News
VLT’s GRAVITY Instrument Detects ‘Tug’ from Colossal Exomoon; Could Be Largest Natural Satellite Ever Found

VLT’s GRAVITY Instrument Detects ‘Tug’ from Colossal Exomoon; Could Be Largest Natural Satellite Ever Found

Discovery of the orbital wobble may challenge current definitions of moons and advance the hunt for exomoons.

Written by Gadgets 360 Staff | Updated: 24 January 2026 17:19 IST

VLT’s GRAVITY Instrument Detects ‘Tug’ from Colossal Exomoon; Could Be Largest Natural Satellite Ever Found

Photo Credit: NASA

Orbital wobble suggests HD 206893 B may host massive moon, redefining moon classification

Click Here to Add Gadgets360 As A Trusted Source

Highlights

Orbital wobble hints at a moon nearly half Jupiter’s mass
Potential exomoon would dwarf all known Solar System moons
Discovery could redefine what astronomers classify as a moon

Astronomers observed a subtle wiggle in the orbit of a massive exoplanet. They concluded that it may be hiding a huge moon. The massive exoplanet known as HD 206893 B is 28 times more massive than Jupiter. It has a back-and-forth motion which is an indicator of the probable presence of a giant moon half the mass of Jupiter. The giant moon is thousands of times more massive than other large moons in our Solar System. It can easily force a re-definition of what is actually a moon.

A Wobbling Giant and Its Enormous Moon

According to the new research, astronomers have employed the Very Large Telescope's technology, known as GRAVITY and have detected a wobbly motion. HD 206893 B is a significant, massive gas giant with a mass of about 28 times that of Jupiter and is approximately 133 light-years away from us. The wobbles take nine months.

A moon about one-fifth the distance of the sun and the Earth, or about 0.2 AU away, has been found Its mass would weigh about 40% as much as Jupiter's mass—about nine times as massive as the planet Neptune, and would dwarf the Solar System's moon mass.

NASA Selects Three New Lunar Science Instruments for Artemis Moon Missions

Redefining Moons and the Search for Exomoons

A moon this massive challenges our definitions, and exomoons are notoriously hard to detect – none has been unambiguously confirmed yet. Astronomers note that any object orbiting a planet or brown dwarf is generally called a moon (no strict definition exists), so at nearly half Jupiter's mass, this companion blurs the line between a moon, a double-planet system, or a sub-brown-dwarf.

Confirming it would likely be the first official exomoon discovery, highlighting how exomoon science is evolving – as techniques improve, our concept of what constitutes a “moon” may change.

Comments

Catch the latest from the Consumer Electronics Show on Gadgets 360, at our CES 2026 hub.

Further reading: Science, studies