A celestial triple-threat: The solar system's first three-lobed asteroid

Space · Published 21 October 2026 Swipe more like this →

In short: For over 150 years, astronomers knew only that asteroid 44 Nysa was a bright speck in the main belt. It took modern high-contrast imaging to reveal its bizarre anatomy: a massive body composed of three distinct lobes joined together like a cosmic welding project.

Discovered in 1857, 44 Nysa is one of the largest and brightest E-type asteroids, characterized by a surface rich in enstatite. While previous observations from instruments like the Hubble Space Telescope suggested it might be bi-lobed—similar to many other asteroids—new joint observations from the Large Binocular Telescope (LBT) in Arizona and the Very Large Telescope (VLT) in Chile have revealed a much more complex structure.

Measuring approximately 47 miles (75 kilometers) across, these pictures depict an uneven mass containing two distinct 'colli' valleys. Scientists view these as 'necks', implying Nysa is a contact trinary formed by three individual parts merging at low speeds to bond instead of breaking apart. While contact binaries like Comet 67P are known, a triple-lobed object of this nature has never been seen before.

Alternatively, the asteroid could be a single body so severely battered by space debris that it mimics a trinary shape—a possibility that would also be a first for science. Adding to the complexity, the team identified a small moon, designated S/2026 (44) 1, which is about 0.6 miles (1 kilometer) wide and orbits at a distance of at least 106 miles (170 kilometers).

To capture these details, scientists used adaptive optics to counteract atmospheric blurring and specialized image-processing to remove the asteroid's bright halo. These techniques, originally developed for hunting exoplanets, allow researchers to study Nysa's interior strength and formation history without leaving Earth.

General information, not professional advice. Spotted an error? Flag the card or see corrections and complaints.

Intellect Plus is a visual educational discovery platform for exploring fascinating facts and ideas. Brain Food, Not Brain Rot. What is Intellect Plus?

Related

• Large asteroids show distinct shapes and densities based on rotation and composition
• Every asteroid in the main belt combined weighs just 3 percent of our Moon
• Once dismissed as celestial vermin, asteroids are now the keys to our solar history.
• A routine asteroid flyby reveals a bizarre, contact-binary moon orbiting in deep space
• The asteroid with a secret: How 243 Ida changed our view of the belt
• A comet is both a celestial body and a celestial object at once
• The cosmic ghost: a massive galaxy that never lit up
• Astronomy began with farming calendars and still welcomes amateurs to discover comets
• By 1900, astronomers had measured the distances to only about 60 stars
• Celebrating four centuries of looking up at the stars
• The dual nature of asteroids as celestial guardians and looming threats
• Cecilia Payne found what stars are made of and was told to hedge

More in Astronomy · More in Space · Latest · A–Z · All topics