Indian-Led Team Discovers White Dwarf Binary with Fastest Shrinking Orbit

Key facts

• An international team led by Indian astronomers identified a pair of white dwarfs, eRASSU J0608, orbiting each other every 6.2 minutes, with their orbit shrinking faster than in two other known systems of the same type.
• The binary completes an orbit in 374.15 seconds and is among the most rapidly evolving ultracompact double-white-dwarf binaries known.
• Researchers tracked the system's motion for three and a half years using NASA's NICER telescope, the Einstein Probe mission, and archival XMM-Newton data.
• The orbital period is decreasing at a rate of approximately 4.7 × 10⁻¹¹ seconds per second, exceeding the decay observed in HM Cnc and V407 Vul.
• The rapid decay is consistent with gravitational radiation, and the system's predictable signal could make it a verification source for future space-based observatories like LISA, planned for launch in 2035.
• The system's distance remains uncertain, requiring further observations.