A newly identified quadruple star system, referred to as UPM J1040-3551 AABBAB, comprises a pair of cold brown dwarfs along with young red dwarfs.
An artistic depiction of the UPM J1040-3551 system amidst the Milky Way, as seen by the ESA Gaia satellite. On the left, the UPM J1040-3551 AA&AB is portrayed as a distant bright orange dot, showcasing the two M-shaped stars in orbit. Conversely, in the foreground on the right, a pair of cold brown dwarfs – UPM J1040-3551 BA & BB – have been on a long trajectory from each other for decades, collectively orbiting the UPM J1040-3551 AAB in a vast orbit taking over 100,000 years to complete. Image credits: Jiaxin Zhong / Zenghua Zhang.
The UPM J1040-3551 AABBAB system is situated in the constellation Antlia, approximately 82 light-years from Earth.
In this system, AAB denotes the brighter pairs AA and AB, while BAB refers to the more distant sub-components BA and BB.
“The hierarchical structure of this system makes the findings particularly intriguing, as it is essential for maintaining stable orbits over extended periods,” explains Professor Zenghua Zhang from Nanjing University.
“These two objects have orbited individually for decades, but collectively they have circled a common center of mass for more than 100,000 years.”
The two pairs are separated by 1,656 astronomical units (Au), where 1 Au represents the average distance from the Earth to the Sun.
The brighter pair, UPM J1040-3551 AAB, appears orange when viewed in visible wavelengths.
These stars possess a temperature of 3,200 K (approximately 2,900 degrees Celsius) and have a mass about 17% that of the Sun.
With a visual magnitude of 14.6, this pair is roughly 100,000 times dimmer than Polaris, the North Star, when viewed at visible wavelengths.
The fainter pair, UPM J1040-3551 BAB, comprises two cooler brown dwarfs that emit almost no visible light and are about 1,000 times dimmer than the AAB pair in near-infrared wavelengths.
These brown dwarfs are classified as T-type, with temperatures of 820 K (550 degrees Celsius) and 690 K (420 degrees Celsius), respectively.
“This is the first documented case of a quadruple system featuring a pair of T-type brown dwarfs orbiting two stars,” states Dr. Maricruz Gálvez-Ortiz, an astronomer at the Spanish Center for Astronomy.
“This discovery presents a unique opportunity for studying these enigmatic objects.”
“Brown dwarfs, alongside a diverse array of stellar companions, are invaluable for establishing age benchmarks,” comments Hugh Jones, a professor at the University of Hertfordshire.
“The UPM J1040-3551 system is particularly significant, as H-Alpha emissions from the bright pairs suggest that the system is relatively young, estimated to be between 200 and 300 million years old.”
The research team is optimistic that high-resolution imaging techniques could eventually resolve the brown dwarf pairs, facilitating precise measurements of their orbital dynamics and masses.
“This system offers a dual benefit for brown dwarf science,” remarks Adam Burgaster, a professor at the University of California, San Diego.
“It serves as both an age benchmark for calibrating cold atmospheric models and a mass benchmark for validating evolutionary models, provided that we can effectively resolve and track these brown dwarf binaries.”
“The discovery of the UPM J1040-3551 system marks a significant milestone in enhancing our understanding of these elusive objects and the various formation pathways of stellar systems near our Solar System.”
Findings are detailed in a study published in Monthly Notices of the Royal Astronomical Society.
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Zh Zhang et al. 2025. Benchmark Brown Dwarf – I. Blue M2 + T5 Wide Binary and Possible Young People [M4 + M4] + [T7 + T8] Hierarchical rectangles. mnras 542(2): 656-668; doi: 10.1093/mnras/staf895
Source: www.sci.news
