Radial velocity reveals for the first time planetary mass object around brown dwarf CD-35 2722 B

Star system: CD-35 2722 A | Distance from the Sun: 72.9 light years

Evidence for satellites orbiting the brown dwarf CD-35 2722 B has been identified using precise light measurements. While thousands of planets have been found orbiting stars, satellites around objects outside our solar system—known as exosatellites—have remained elusive and controversial. This study presents a strong detection of at least one, and possibly two, massive objects circling this brown dwarf, providing new data on how such systems form and evolve.

The research utilized radial velocity analysis, a technique that tracks the subtle "wobble" of a central object caused by the gravitational pull of smaller orbiting bodies. By observing the light spectrum of the brown dwarf with the VLT/CRIRES+ instrument, researchers detected periodic signals consistent with the presence of orbiting companions. This is the first successful application of this method to detect satellites.

The primary satellite candidate has a minimum mass of 0.743 times that of Jupiter and completes an orbit every 169 days. A second, smaller candidate with a minimum mass of 0.277 Jupiter masses was also identified with an 87-day period. These orbital periods suggest the two satellites exist in a 2:1 mean motion resonance, meaning the outer satellite completes one orbit for every two orbits of the inner satellite, a pattern also observed among the satellites of Jupiter.

Key findings
- Detection of a massive satellite around the brown dwarf CD-35 2722 B.
- Primary satellite candidate has a minimum mass of 0.743 Jupiter masses.
- Secondary satellite candidate identified with a minimum mass of 0.277 Jupiter masses.
- Orbital periods of 169 and 87 days indicate a 2:1 mean motion resonance.
- First successful use of radial velocity analysis to provide evidence for exosatellites.

Scientific study

Planetary-Mass Exosatellite Detected Around the Substellar Companion of a Star (external link)