Ground Telescopes Reveal 75-Km Asteroid Nysa Has 3 Lobes and a 1-Km Moon

2 articles · Updated · spacedaily.com · Aug 18

Images from Arizona’s Large Binocular Telescope and Chile’s Very Large Telescope resolved a second neck on 75-kilometre asteroid Nysa, making it the first confirmed three-lobed asteroid ever imaged.
Adaptive-optics observations from February and March produced near spacecraft-quality views of a body more than 200 million kilometres away, exposing details that earlier light-curve studies had blurred into one elongated shape.
The same data also uncovered a previously uncatalogued moon—provisionally S/2026 (44) 1—about 1 kilometre across and orbiting at least 170 kilometres from Nysa.
Researchers say the shape could reflect either a contact trinary assembled from collision fragments or a glancing hit-and-run impact, but ground imaging alone cannot distinguish between those formation scenarios.
Nysa has been tracked since 1857, and the finding suggests other apparently two-lobed asteroids may hide unresolved extra necks that could force updates to small-body formation models.