Altozillaalso known as the 2001 UQ18, is located outside the solar system, 6 billion km (3.7 billion miles), or 44 times the distance between the Earth and the Sun.
This artist’s concept illustrates one of the possible scenarios for Kuiper Belt’s Altjira system. Image credits: NASA/ESA/Joseph Olmsted, Stsci.
“The Hubble images show two Kuiper Belt Objects (KBOs) about 7,600 km (4,700 miles) apart,” says Meianelsen, an astronomer at Brigham Young University and a colleague.
“However, Altjira’s repeated observations of the unique cooperative movement show that the inner object is indeed two bodies very close to each other.
“In small, far-flung objects, we need to discover that the separation between the two inner members of the system is part of the pixels of Hubble’s camera, using non-imaging methods.”
Astronomers gathered data from the Hubble and WM Keck Observatory for 17 years of observation baselines and looked at the trajectory of objects outside the Altjira system.
“Over time, the direction of the trajectory of the outer object changes, indicating that the inner object is either very elongated or in fact one of two separate objects,” says Dr. Dalin Lagoziczin of Brigham Young University.
“The triple system was perfect when putting Hubble data into different modeling scenarios,” Nelsen added.
“Other possibilities are that the inner object is a contact binary, so close that two separate bodies touch each other, or in fact, oddly flat as pancakes.”
Of the 40 identified binary objects in the Kuiper belt, of another system, Lempoit is known to be triple.
“Now, Altjira and Lempo are likely triples, so they are more likely to be looking for a population of three-body systems formed by the same situation, rather than a strange ball,” the astronomer said.
“But building that evidence requires time and repeated observation.”
The only Kuiper Belt objects explored in detail are PL Pun and the small object Arrocos that NASA’s New Horizons mission visited in 2015 and 2019, respectively.
New Horizons showed that Arrokoth is a contact binary. This means that in the case of KBO, two objects that have moved close to each other are currently touched or merged, often in the form of peanuts.
“Altozilla is the “cous” of Arokos, a member of the Kuiper Belt Objects of the same group,” Dr. Lagozin said.
“The Altjira is 10 times the Arocos, which is 200 km (124 miles) wide.”
“There is no mission that Altozilla plans to fly to get Arrocos level details, but there are other upcoming opportunities to further study the intriguing system,” Nelsen said.
“Altozilla is entering the season of the eclipse, where the outer body passes in front of the central body.”
“This will continue for the next 10 years and give scientists a great opportunity to learn more about it.”
Team’s paper It was published in Journal of Planetary Science.
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Maia A. Nelsen et al. 2025. Beyond the point square. IV. The Transneptinian object Altjira is a hierarchical triple, possibly discovered by non-kipler movements. planet. SCI. j 6, 53; doi:10.3847/psj/ad864d
Source: www.sci.news
