Broadly speaking, our solar system is simply a collection of planets, their moons, and other cosmic objects like asteroids that exist in gravitational orbits around the sun. There are also countless similar systems. But a star system about 72 light years from Earth is unlike anything researchers have ever seen. In fact, astronomer Kevin Hoy would go so far as to describe CD-35 2722 as “super strange” compared to our corner of the galaxy.

“The system is somewhat difficult to define using words based on the solar system like ‘planet’ and ‘moon,'” astronomer from Universidad Diego Portales of Chile and the Millennium Nucleus of Young Exoplanets and their Moons (YEMS) said recently in a statement.

The system is detailed in a study co-authored by Hoy and recently published in the journal Nature.

Hoy and his colleagues recently pointed the European Southern Observatory’s Very Large Telescope (ESO’s VLT) at the strange young system CD-35 2722 that is centered on a star about half the mass of the Sun. Orbiting this star is a brown dwarf, which is a type of gas giant that is larger than a planet, but smaller than a star. In this case, the brown dwarf is about 30 times more massive than Jupiter, but it is not alone. Orbital that The object is another entity with a mass equivalent to that of Jupiter itself.

“The exosatellite is clearly massive enough to be a planet, but it does not orbit a star, although it orbits an object that orbits a star,” Hoy said.

New ‘exomoon’ detection defies cosmic labels

So is it a moon or not?

“We have a clear delineation between the planets and the sun in the solar system, so defining things like moons is simple,” added YEMS director and study co-author Alice Zurlo. “In the CD-35 2722 system, where we are blurring the lines between stars, planets and moons, everything becomes more complicated to describe.”

According to their study, Hoy, Zurlo and his team suspect that their mystery may be an exosatellite or exomoon. These are natural planetary satellites located outside the solar system. Although researchers have documented more than 6,000 exoplanets throughout the cosmos, the few exomoon candidates still lack sufficient evidence to prove their identities. If true, it would be the first of its kind confirmed by astronomers. For now, more observations are needed before astronomers can definitively classify this strange entity, but it’s also a matter of scientific semantics.

“Being the third wheel of this system makes us want to call it a moon, even if it looks nothing like the small rocky moons we have in our system.”

Regardless, the latest exomoon suspect marks an important moment in universe exploration.

“As exotic as it is, this system is truly unique and represents a breakthrough: the first plausible detection of an exosatellite,” Zurlo said.

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