Caltech Researchers Discover Rare Merger of Two Brown Dwarfs

The failed stars are expected to form a new, brighter star through their union.

Mar. 19, 2026 at 2:55am

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Researchers at Caltech have identified a rare pair of brown dwarfs - objects that fall between the mass of planets and stars - in which one is actively siphoning material from the other. This mass transfer between the two dim celestial bodies is expected to lead to a merger, creating a new, brighter star.

Why it matters

Brown dwarfs are often dismissed as "failed stars," but this discovery shows they can exhibit dynamic physics and even come together to form a new, more luminous star. The findings provide insights into the life cycle of these enigmatic objects that occupy the boundary between planets and stars.

The details

Searching through archival observations from the Zwicky Transient Facility at Caltech's Palomar Observatory, researchers identified a very tight-knit pair of brown dwarfs where one is actively pulling material from the other. This mass transfer is expected to lead to the brown dwarfs merging, either igniting the gaining brown dwarf into a new star or resulting in the formation of a single, brighter star.

  • The findings were published on March 19, 2026 in The Astrophysical Journal Letters.

The players

Samuel Whitebook

A Caltech graduate student and lead author of the study.

Tom Prince

The Ira S. Bowen Professor of Physics, Emeritus, at Caltech and a co-author on the study.

Dimitri Mawet

The David Morrisroe Professor of Astronomy at Caltech, a senior research scientist at NASA's Jet Propulsion Laboratory, and a co-author on the study.

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What they’re saying

“The failed stars get a second chance. Brown dwarfs don't have internal engines like stars do, but this result shows they can exhibit very interesting dynamic physics.”

— Samuel Whitebook, Caltech graduate student

What’s next

The researchers plan to continue studying the pair of brown dwarfs to better understand the process of how they are merging and the implications for the formation of new stars.

The takeaway

This discovery challenges the notion of brown dwarfs as mere "failed stars" and demonstrates their potential to participate in dynamic stellar processes, ultimately leading to the birth of new, brighter stars.