China FAST Telescope Discovers Lightest Binary Neutron Star System Ever Recorded
China’s Five-hundred-meter Aperture Spherical radio Telescope has discovered a binary neutron star system designated PSR J1856-0039, featuring an ultrashort orbital period of 2.36 hours and a combined mass 2.488 times that of the sun, chinadailyasia.com reported. The system stands as the lightest binary neutron star system confirmed to date, according to findings published in the journal Physical Review Letters, which selected the research as an editors’ highlight.
How the Snapshot Survey Mode Scanned the Milky Way
To detect the system, the telescope utilized an L-band receiver capable of observing 19 areas of the sky simultaneously, according to chinadailyasia.com. Scientists employed a snapshot survey mode developed by the research team to efficiently scan the Milky Way’s stellar disk, the broad and densely populated region where most pulsars reside.
Solar Masses Near the Theoretical Minimum
Neutron stars represent the extremely dense remains of massive stars that exploded as supernovae. Despite spanning only about 20 kilometers across, they pack more mass than the sun and rotate rapidly, utilizing pulsars as precise cosmic clocks.
Testing Einstein’s Theory of General Relativity
The tight orbit of PSR J1856-0039 provides a natural laboratory for studying extreme physics and gravity under intense conditions. The two neutron stars are losing energy by emitting gravitational waves, causing their orbit to shrink at a rate that closely matches theoretical predictions.
Eighty-Two Million Years Until the Final Merger
The combination of a small orbital tilt and an ultrashort period also creates an opportunity to detect frame dragging, a phenomenon in which a spinning object drags surrounding space and time along with its rotation. Long-term, high-precision monitoring will help determine how the pulsar’s mass is distributed as it spins, providing clues about its internal structure and the origins of heavy elements in the universe.
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