The recently identified moon has an approximate diameter of 38 kilometers (23.6 miles) and a V magnitude of 28, making it the faintest moon ever found orbiting a trans-Neptunian object.
This image of Quaor and its satellite Waywot was captured by the NASA/ESA Hubble Space Telescope on February 14, 2006. Image credit: NASA / ESA / Hubble / Michael E. Brown.
Discovered on June 4, 2002, Quaor is a trans-Neptunian body approximately 1,100 km (690 miles) in diameter.
Similar to the dwarf planet Pluto, Quaor is located within the Kuiper Belt, a frigid region populated with comet-like objects.
The satellite, also referred to as 2002 LM60, orbits between 45.1 and 45.6 astronomical units (AU) from the Sun, completing an orbit every 284.5 years.
In 2006, astronomers confirmed Quaor’s moon Waywot, measuring 80 km (50 miles) in diameter and orbiting at a radius of 24 around Quaor.
Recently, two rings, designated Q1R and Q2R, were identified surrounding Quaor.
“Stellar occultations over the last decade have indicated the presence of rings around small celestial bodies,” remarked Benjamin Proudfoot, an astronomer at the Florida Space Institute, alongside his colleagues.
“Among these small ring systems, the ring around Quaor is notably enigmatic.”
“The two rings discovered thus far lie well beyond Roche’s limits and exhibit heterogeneity.”
“Quaor’s outer ring, dubbed Q1R, seems to be at least partially confined by mean-motion resonance with Quaor’s moon Waywot, as well as by spin-orbit resonance linked to Quaor’s triaxial structure.”
“The inner ring, Q2R, appears less dense, and its confinement remains more indefinite.”
“Recently, simultaneous dropouts from two telescopes during a stellar occultation indicated the existence of a previously unidentified dense ring around a moon, or Quaor.”
“The length of the dropout suggests a minimum diameter/width of 30 km.”
Artist’s depiction of Quaor and its two rings, with Quaor’s satellite Waywot on the left. Image credit: ESA/Sci.News.
In a recent study, astronomers sought to further characterize the orbit of this new satellite candidate.
They determined that the object is likely on a 3.6-day orbit, close to a 5:3 mean-motion resonance with Quaor’s outermost known ring.
Additionally, they explored the potential for observing satellites through further stellar occultations.
“Quaor will be well-positioned within the Scute nebula for the next 10 years, providing the best opportunity for occultation throughout its 286-year orbit,” the researchers stated.
“Current ground-based and space-based telescopes will struggle to detect the newly discovered moon, given its brightness (9 to 10 magnitude fainter than Quaor) and its angular distance from Quaor.”
“Our analysis of Webb/NIRCam images from the Quaor system did not reveal any convincing evidence of the satellite,” they added.
“Direct imaging with existing equipment would necessitate considerable telescope time to blindly reacquire the satellite’s phase, even if the satellite were detectable.”
“However, future generations of telescopes will likely have the capability to easily observe it.”
The discovery of this new moon suggests that the ring around Quaor may have originally formed from a broad impact disk and may have undergone significant evolution since its creation, according to the researchers.
“Studying the formation and evolution of the lunar disk system will yield valuable insights into the development of trans-Neptunian objects,” they remarked.
“We advocate for advanced tidal mechanics, hydrodynamics, and collisional modeling of the Quaor system.”
The team’s paper has been submitted for publication in Astrophysical Journal Letters.
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Benjamin Proudfoot et al. 2025. Orbital characteristics of a newly discovered small satellite around Quaor. APJL in press. arXiv: 2511.07370
Source: www.sci.news
