Astronomers Detect First Exomoon Candidate Orbiting Brown Dwarf CD-35 2722 B

exomoon brown dwarf CD-35 2722 radial velocity exosatellite

An international team of astronomers led by ESO student Kevin Hoy reported the discovery of a massive gas‑giant object orbiting the brown dwarf CD‑35 2722 B, a companion to the red dwarf star CD‑35 2722. The object, nicknamed an “exosatellite,” has a minimum mass of about 0.9 Jupiter masses and completes an orbit roughly every 170 days. It was identified by measuring the subtle radial‑velocity wobble of the brown dwarf with the CRIRES+ instrument on the Very Large Telescope.

The system lies about 72–73 light‑years away in the constellation Columba and includes a star half the mass of the Sun, the brown dwarf (≈37 Jupiter masses), and the newly detected satellite. Because the satellite does not orbit a star, its classification as a moon or a planet is ambiguous; the International Astronomical Union has no official definition for such an object. The researchers suggest the term “exosatellite” and note that this is the first plausible detection of a moon‑like body around a brown dwarf, opening new questions about how moons, planets, and sub‑stellar objects are defined.

Entities: Alice Zurlo · CD-35 2722 · European Southern Observatory (ESO) · Kevin Hoy · brown dwarf CD‑35 2722 B

Claims

What the coverage asserts, and how well corroborated each claim is across sources.

[● 4 SOURCES] A gas‑giant object with a minimum mass of about 0.9 Jupiter masses orbits the brown dwarf CD‑35 2722 B. (multiple articles)
[● 4 SOURCES] The discovery blurs traditional categories of stars, planets, and moons, prompting the use of the term “exosatellite.” (multiple articles)
[● 4 SOURCES] This is the first plausible detection of an exomoon‑like satellite around a brown dwarf. (multiple articles)
[● 2 SOURCES] The CD‑35 2722 system is located about 72–73 light‑years from Earth and its primary star has roughly half the Sun’s mass. (multiple articles)
[● 4 SOURCES] The object completes an orbital period of roughly 170 days around the brown dwarf. (multiple articles)
[● 3 SOURCES] The International Astronomical Union currently has no official definition for an “exomoon.” (multiple articles)
[● 2 SOURCES] The detection was made using radial‑velocity measurements with the CRIRES+ instrument on ESO’s Very Large Telescope. (multiple articles)