Rare Quadruple Star System Discovered with Brown Dwarfs and Red Dwarfs

A groundbreaking discovery of a hierarchical quadruple star system could deepen our understanding of brown dwarfs, often called “failed stars” due to their inability to ignite nuclear fusion in their cores. These objects form like stars but lack sufficient mass, making their evolution difficult to trace.

The system, named UPM J1040−3551 AabBab, is situated approximately 82 light-years from Earth and uniquely comprises a pair of cold brown dwarfs orbiting two young red dwarf stars. The two stellar pairs are separated by a vast distance, taking over 100,000 years to complete an orbit around their common center of mass.

Using data from the European Space Agency’s Gaia spacecraft and NASA’s WISE infrared survey, astronomers observed the movement of the system’s components. The stars and brown dwarfs are moving together, confirming their gravitational connection. The system’s hierarchical structure allows for long-term orbital stability, with the pairs orbiting each other over decades and the entire system completing a full orbit roughly every 100,000 years.

Although the red dwarf stars (Aab) are the brightest in the system, they are so faint that they would only be visible to the naked eye if within 1.5 light-years. The brown dwarfs (Bab), emitting minimal visible light, are about“`html

Discovery of a Unique Quadruple Star System with Brown Dwarfs and Red Dwarfs

A rare and complex quadruple star system has been identified, offering new insights into brown dwarfs—objects often called “failed stars” because they lack enough mass to sustain nuclear fusion. Unlike true stars, brown dwarfs form similarly but do not reach the high temperatures necessary for fusion, making their properties challenging to study over time.

The system, named UPM J1040−3551 AabBab, is located approximately 82 light-years from Earth. It features two red dwarf stars and two brown dwarfs arranged in a hierarchical structure, with the brown dwarfs orbiting the pair of red dwarfs. The entire system is separated by an immense distance, taking more than 100,000 years to complete an orbit.

Scientists used data from the Gaia spacecraft and NASA’s WISE infrared telescope to track the components’ movement. Both the red dwarf pair (Aab) and the brown dwarf pair (Bab) move in the same direction and at similar velocities, confirming their gravitational relationship. The distinct orbital configurations, with their long periods, suggest the system remains stable over millions of years, making it a significant natural laboratory for studying such objects.

While the red dwarfs are faint, they are the brightest components of the system and would only be visible to the naked eye from close proximity. The brown dwarfs, being several hundred times fainter and only detectable in infrared, are unusual examples of T-type brown dwarfs, with masses between 10 to 30 times that of Jupiter.

Spectroscopic observations performed with the SOAR Telescope in Chile confirmed the characteristics of each component. The red dwarf stars have masses about 17% that of the Sun, with temperatures around 2,900°C, while the brown dwarfs have temperatures between 550°C and 420°C, solidifying their classification as some of the coolest brown dwarfs known.

Research highlights the importance of such systems in resolving the “age-mass degeneracy” problem—determining whether a brown dwarf’s properties are due to its age or mass. The presence of a companion star with independently known age helps break this degeneracy, offering critical benchmarks for evolutionary models.

This discovery paves the way for future detailed studies, including high-resolution imaging to measure orbital motions precisely, which will enhance our understanding of brown dwarf formation and evolution.

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