Can asteroids orbit each other in pairs of three, also called a three-body or triple system, like stars? This is what a recent study published in The Planetary Science Journal hopes to address as a team of researchers from Brigham Young University (BYU) and the Lowell Observatory have discovered only the second triple system of asteroids within the Kuiper Belt, also known as trans-Neptunian objects (TNOs). This study has the potential to help astronomers better understand the gravitational properties of planetary bodies, along with how the solar system formed billions of years ago.
"The universe is filled with a range of three-body systems, including the closest stars to Earth, the Alpha Centauri star system, and we're finding that the Kuiper Belt may be no exception," said Maia Nelsen, who received a Bachelor’s of Science in Physics and Astronomy from BYU in 2024 and is lead author of the study.
For the study, the researchers used NASA’s Hubble Space Telescope to observe and analyze the 148780 Altjira system, which was first discovered in October 2001 and has been designated as a binary system until now. The only other triple system involving solar system small bodies is (47171) Lempo, which was first discovered in October 1999 and designated as a triple system in 2007 after a third object was discovered. While the two known objects that comprise 148780 Altjira orbit approximately 4,700 miles apart, Hubble observations revealed the inner object could be comprised of two separate objects.
"Over time, we saw the orientation of the outer object's orbit change, indicating that the inner object was either very elongated or actually two separate objects," said Dr. Darin Ragozzine, who is an associate professor in the Department of Physics and Astronomy at BYU and a co-author on the study.
Going forward, the team aspires to take advantage of observational opportunities of the 148780 Altjira system, with the goal of determining if other TNO binary systems are triple systems due to the results from this study.
What new discoveries about triple systems will researchers make in the coming years and decades? Only time will tell, and this is why we science!
As always, keep doing science & keep looking up!
Sources: The Planetary Science Journal, Space Telescope Science Institute, Wikipedia, Wikipedia (1), EurekAlert!
Featured Image Credit: NASA, ESA, Joseph Olmsted (STScI)
