Two dead stars orbit each other every 6.2 minutes; their orbit is shrinking faster than in two other known systems

An international team led by Indian astronomers has identified a pair of white dwarfs locked in an extraordinarily tight orbit that is shrinking faster than that of two other well-known systems of the same type. The binary, known as eRASSU J060839.5–704014 or eRASSU J0608, completes an orbit in just 374.15 seconds, or about 6.2 minutes. Researchers tracked the system's orbital motion for three and a half years using observations from NASA's NICER telescope and the Chinese-led Einstein Probe mission, together with archival data from the European Space Agency's XMM-Newton observatory. Their findings, published in The Astrophysical Journal Letters titled Rapid Orbital Decay in the Ultracompact Double-degenerate Binary eRASSU J060839.5–704014 on August 10, 2026, show that the system is among the most rapidly evolving ultracompact double-white-dwarf binaries currently known.