A trans-Neptunian object designated 2014 WC510 is, in fact, a close binary system, according to an analysis of data obtained by the Research and Education Collaborative Occultation Network (RECON), a network of small telescopes spread over 2,000 km (1,243 miles) in the western United States and Canada.
2014 WC510 was discovered on September 8, 2011, by a team of astronomers using with the Pan-STARRS1 telescope on Mount Haleakala in Hawaii.
This trans-Neptunian object orbits the Sun at a distance between 30 and 49 AU once every 246.8 years.
It is located in the Kuiper Belt and is classified as a plutino, a trans-Neptunian object that is locked in a 2:3 orbital resonance with the ice giant Neptune.
The binary nature of 2014 WC510 was revealed using a phenomenon called stellar occultation, which occurs when an object passes between Earth and a distant star which hides, or occults, the star from view.
“In this instance, the occulted star also turned out to be a binary system,” said Dr. Marc Buie, a researcher at the Southwest Research Institute.
“Binary stars are not unusual and binary objects are not unusual. But it is unusual that we had a binary trans-Neptunian object occulting a binary star.”
The scientists determined that the primary component of 2014 WC510 has a diameter of 181 km (112.5 miles) and the secondary 138 km (86 miles).
“What’s also interesting and unusual is this object’s characteristics,” said Dr. Rodrigo Leiva, also from the Southwest Research Institute.
“The two components are quite close, only 350 km (217.5 miles) apart. Most binary trans-Neptunian objects are very separated, usually 1,000 km (621.4 miles) or more.”
“This closeness makes this type of binary trans-Neptunian object difficult to detect with other methods, which is what RECON was designed to accomplish.”
The team will continue to search for previously unobserved trans-Neptunian objects, with the aim of discovering whether close binaries are common or unusual in our Solar System.
“Most models of the Solar System indicate that binaries are very common, particularly close binaries like this one,” Dr. Leiva said.
“If you have an accurate measurement of how common they are, you can fine tune these models.”
“Our overarching aim is to know how common close binary trans-Neptunian objects are,” Dr. Buie said.
“Is this object one in a million or just like 90% of them? This is fueling our knowledge for building better models of how the Solar System formed.”
The team’s paper was published in the Planetary Science Journal.
Rodrigo Leiva et al. 2020. Stellar Occultation by the Resonant Trans-Neptunian Object (523764) 2014 WC510 Reveals a Close Binary TNO. Planet. Sci. J 1, 48; doi: 10.3847/PSJ/abb23d