An international team of astronomers has revealed that the main-belt asteroid (44) Nysa possesses a bizarre three-lobed structure, making it a world unlike any previously observed in the solar system University of Arizona News. Originally discovered in 1857 Newscientist, Nysa is one of the brightest and largest SCI E-type asteroids in the main belt located between Mars and Jupiter Newscientist. Continuous observations conducted on February 15, 2026, captured detailed views of the object Skyandtelescope, detailing the findings in a study titled Unmasking (44) Nysa: Evidence for a Trilobate Structure
accepted for publication in the journal Astronomy & Astrophysics SCI.
Astronomers Uncover First-Ever Three-Lobed Asteroid and Tiny Moon
Researchers built a three-dimensional model of Nysa Newscientist by combining adaptive optics images with extensive photometric observations from observatories around the globe University of Arizona News. The data show an arch-shaped object comprised of one large and two smaller chunks joined together by two narrow neck regions Skyandtelescope. While two-lobed, or bilobate, asteroids have been identified previously, Nysa displays a unique trilobate structure SCI. If compressed into a sphere, Nysa would measure roughly 75 kilometers across Skyandtelescope (with source figures citing an 80 km span in separate image analysis SCI).
Advanced Ground-Based Imaging Techniques
Unlocking Nysa’s true shape required cutting-edge instrumentation. Scientists utilized the SPHERE instrument SCI (specifically its ZIMPOL component University of Arizona News) on the European Southern Observatory’s Very Large Telescope in Chile, alongside the SHARK-VIS instrument on the Large Binocular Telescope in Arizona SCI, Newscientist. Both instruments deployed adaptive optics systems featuring computer-controlled actuators to compensate for atmospheric blur SCI, University of Arizona News.
The images reveal a remarkably unusual object,
said Dr. Kate Minker, an astronomer at Lowell Observatory and lead author of the study SCI, Prnewswire. The most likely explanation is that Nysa is either a contact trinary, consisting of three connected components, or an extremely irregular coherent body unlike anything we’ve previously observed.
Researchers noted that these observations achieved a level of clarity rivalling spacecraft imaging SCI. Specialized image-processing techniques were also implemented to eliminate the bright halo surrounding Nysa SCI, Prnewswire.
Unresolved Formation Mysteries and Material Strength
Astronomers are investigating multiple hypotheses regarding Nysa’s origin SCI. Beyond the contact trinary concept—where three separate bodies drifted together until they touched—the asteroid may have formed from a single parent body heavily deformed by collisions SCI, Skyandtelescope, or via a hit-and-run impact University of Arizona News.
As an E-type asteroid, Nysa’s composition is rich in enstatite, a magnesium-rich silicate mineral, and high metal content Skyandtelescope, Newscientist. With a density exceeding 5 grams per cubic centimeter, Nysa is denser than rock Skyandtelescope. Scientists point out that such durable materials are necessary to support a non-spherical shape against self-gravity, whereas weaker rubble-pile asteroids typically pull themselves into rounder configurations over time Skyandtelescope.
For the first time, we can directly investigate whether those clues point to a deeply indented body or to a true multi-lobed structure,
said Dr. Al Conrad, an astronomer at the Large Binocular Telescope Observatory SCI.
Discovery of a Companion Moon
Alongside the main asteroid body, the imaging campaigns uncovered a previously unknown natural satellite temporarily designated S/2026 (44) 1 Prnewswire. High-contrast imaging methods were borrowed from other branches of astronomy to spot the satellite, whose light would otherwise be eclipsed by Nysa’s intense glare Prnewswire.
The newly detected moon measures approximately one kilometer across Skyandtelescope, Newscientist and orbits at a distance ranging from roughly 170 to 180 kilometers from the primary asteroid’s center of mass Skyandtelescope, Prnewswire. Researchers intend to measure the moon’s orbit in future studies to yield additional insights into Nysa’s interior structure and origins Newscientist.
