Astrophysicists have identified what may be the first exossatélite discovered outside our solar system, according to research published in the journal Nature. This celestial body orbits a brown dwarf—a substellar object more massive than a planet but smaller than a star—which is itself part of a system centered on the star CD-35 2722.
The Discovery of the First Exosatellite
The European Southern Observatory (ESO) announced the finding this Wednesday, following observations made with the Very Large Telescope (VLT) in Chile. Scientists identified the object after detecting minor oscillations in the brown dwarf. By analyzing these gravitational signatures, researchers concluded that the satellite is at least as massive as Jupiter, while the brown dwarf it orbits contains more than 30 times the mass of Jupiter.
Did you know?
The newly identified body is considered an “exossatélite” because it orbits a brown dwarf, which in turn orbits a star. This three-level hierarchy distinguishes it from the smaller, rocky moons found within our own solar system.
Defining the Exosatellite Hierarchy
Kevin Hoy, the lead author of the study from Diego Portales University in Chile, noted the unique nature of this system. “The exossatélite is clearly massive enough to be a planet, but it does not orbit a star, although it orbits an object that, in turn, orbits a star,” Hoy stated in an ESO release. He added that its position in the third level of the stellar system justifies its classification as a moon, despite its size and gaseous composition.
According to co-author Alice Zurlo, the object is a “giant gaseous body” circling a high-mass companion.
Why This Finding Matters for Astronomy
For years, astronomers have sought to confirm the existence of natural satellites beyond our solar system. The ESO, an organization of which Portugal is a member state, stated that the detection of such bodies “can help to better understand how diverse their formation and evolution can be.”
Frequently Asked Questions
- What is a brown dwarf? It is a celestial object that sits between the size of a gas giant planet and a small star, lacking the mass to sustain hydrogen fusion.
- Is this the first moon found outside our solar system? Researchers have identified this as a potential first, based on its orbit around a brown dwarf.
- How did scientists find it? The team used the VLT to detect minute oscillations in the brown dwarf, which indicated the gravitational pull of an orbiting satellite.
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