Astronomers discover the first asteroid with three 'heads' in the Solar System

Astronomers have successfully identified the first asteroid in the Solar System that possesses three lobes. This object is located in the asteroid belt between Mars and Jupiter, and during the same observation campaign, a small moon orbiting it was also discovered.

Discovery and Previous Data

This concerns asteroid 44 Nysa, which was discovered in 1857. Prior observations spanning over a century, including images from the Hubble Space Telescope, suggested it might only have two lobes—a feature found in some asteroids and comets.

New Observations and Structure

However, new observations conducted jointly by the Large Binocular Telescope (LBT) in Arizona (USA) and the Very Large Telescope (VLT) in Chile revealed that the body apparently has three lobes, making it the first asteroid of this type. Kate Minker, a researcher at the Lowell Observatory and lead investigator, stated: 'The images show an extremely unusual object.' She added that the most likely explanation is that Nysa is a contact triple, composed of three connected bodies, or it could be a single, highly irregular body unlike anything previously observed.

Imaging Technologies

Obtaining detailed images of the asteroid proved to be a challenging task. Researchers utilized the SHARK-VIS high-contrast imaging instrument installed on the LBT and SPHERE with its ZIMPOL polarimeter on the VLT. These instruments worked in conjunction with adaptive optics systems capable of compensating for distortions caused by the Earth's atmosphere. Furthermore, the team applied specialized image processing techniques to eliminate the intense glare around the asteroid, which could obscure smaller objects.

Antonio Berdeau from the European Southern Observatory (ESO) explained that these observations required a combination with image processing methods specifically designed to further enhance clarity and remove the bright halo around the asteroid that could mask faintly illuminated satellites.

Asteroid Size and Its Moon

The images showed that Nysa has a diameter of about 75 kilometers at its widest point. Scientists also discovered two canyons surrounding part of the asteroid, which they interpret as 'necks' connecting its three lobes. Another surprise was the discovery of a small moon with a diameter of about one kilometer, orbiting the asteroid at a minimum distance of 170 kilometers. This satellite was assigned the temporary designation S/2026 (44) 1. Since it was spotted in two independent campaigns, researchers were able to track its movement around Nysa.

Gianluca Li Causo, a member of the SHARK-VIS team from the National Institute of Astrophysics of Italy (INAF), noted: 'We borrowed specialized techniques from another field of astronomy, known as high-contrast imaging, to detect this small moon whose faint brightness was obscured by the intense glare of the main asteroid.'

Hypotheses on Asteroid Formation

Scientists do not yet know the exact mechanism by which Nysa acquired such an unusual shape. The primary hypothesis is that it is a contact triple formed by three asteroids bound by their own gravity. Another possibility is that the object underwent a collision or a very close flyby of a much larger asteroid in the distant past. In this scenario, strong gravitational forces could have deformed its structure and partially fragmented the body, creating its peculiar shape.

According to the researchers, tracking the orbit of the small moon will help resolve this mystery. Precise measurement of its orbital velocity and period will allow for the calculation of Nysa's mass and density and determine which model best explains its origin.

Scientific Significance and Composition

Beyond its unusual shape, Nysa is scientifically interesting due to its composition. Its surface is rich in enstatite—a low-iron silicate mineral, which makes the asteroid more reflective than most other objects in the main belt. Because of this characteristic, it belongs to the E-type asteroids and is the largest and brightest representative of this group. Scientists believe that these asteroids formed close to the Sun and may have participated in the formation of the rocky planets of the Solar System, including Earth.

If Nysa is indeed a remnant from that period, it could provide valuable information about the state of the inner Solar System about 4.5 billion years ago. The research findings were published in the arXiv scientific repository and are also under review at the journal Astronomy & Astrophysics.

olhardigital.com.brJuly 22, 19:02

International group of astronomers discovers signs of a giant exomoon

An international group of astronomers has recorded signs of a potential natural satellite outside the Solar System. This object is located in a system consisting of a star, a brown dwarf, and a body whose mass approaches that of Jupiter.

Methodology and Observations

The study showed that the celestial body orbits the brown dwarf CD-35 2722 B, which, in turn, moves around a star with approximately half the mass of the Sun. Observations were conducted from October 2023 to February 2026 using the Very Large Telescope (VLT) located in Chile.

The potential exomoon was not observed directly. Its existence was established by changes in the movement of the brown dwarf caused by the gravitational pull of this object. Researchers determined that the orbital period of this body is about 170 days.

Classification and Challenges of the Discovery

Confirmation of this discovery still requires additional measurements. Despite its similarity to moons, this object possesses significantly greater mass than known Solar System satellites and orbits a brown dwarf, not a planet. Therefore, researchers initially used the term exomoon to describe the body orbiting another object outside the Solar System, without defining its classification as a moon or a planet.

The main difficulty lies in the unusual structure of this system. In our Solar System, moons usually orbit planets, while planets orbit stars. The new configuration includes a moon-like body orbiting a brown dwarf—an object situated between the category of a giant planet and a star.

Comments from the Lead Scientist

Kevin Hoy, the lead author of the study and a graduate student at Universidad Diego Portales in Chile, stated in an interview with g1 that the object is difficult to define because scientists are 'truly expanding the boundaries of the words we have invented to describe the Solar System, trying to apply them to a system that is completely unlike ours.'

According to the researcher, the detection of the signal was an important moment for the team, especially because the predictions made based on preliminary data were confirmed by subsequent observations. Hoy specified that the new recordings demonstrated behavior consistent with the model created by the scientists.

Future Research Steps

The brown dwarf CD-35 2722 B has a mass approximately 37 times that of Jupiter. The associated object has dimensions allowing for comparison with a giant planet, although its position in the system allows it to be considered a moon. The team reached this conclusion by tracking small fluctuations in the displacement of the brown dwarf, which were attributed to the gravitational influence of the body in orbit, thus revealing a recurring pattern over time.

Currently, astronomers plan to collect additional data for a more accurate calculation of the possible satellite's mass and confirmation of its trajectory. One planned strategy is the direct measurement of the displacement caused by the object on the brown dwarf. This discovery may expand the search for similar bodies in distant systems. As astronomical instruments develop, the same methodology can help identify smaller exomoons that are more similar in characteristics to satellites found in the Solar System. Hoy believes that the research may also stimulate a review of the criteria for classifying celestial bodies, as such cases could provoke a broader discussion about the meaning of terms like exomoon and exoplanet.