The first observation of neutron star collision was made in August 2017. That discovery had solved a long-standing mystery about the origin of the heavy elements such as gold and platinum.
Now, for the second time, Laser Interferometer Gravitational-wave Observatory (LIGO) has detected a similar event: a pair of neutron stars smashing into each other, for only the second time in its history.
On 2019 April 25, the LIGO Livingston detector observed a compact binary coalescence with a signal-to-noise ratio of 12.9. Detailed observations confirmed that the event was indeed likely the result of the merger of two neutron stars.
Jo van den Brand, Virgo Spokesperson, and professor at Maastricht University said, “We have detected a second event consistent with a binary neutron star system, and this is an important confirmation of the August 2017 event that marked an exciting new beginning for multi-messenger astronomy two years ago.”
Neutron stars are the remnants of dying stars that undergo catastrophic explosions as they collapse at the end of their lives. When two neutron stars spiral together, they experience a violent merger that sends gravitational shudders through the fabric of space and time.
LIGO became the first observatory to detect gravitational waves in 2015 directly; in that instance, the waves were generated by the fierce collision of two black holes. Since then, LIGO and Virgo have registered dozens of additional candidate black hole mergers.
The LIGO data reveal that the combined mass of the merged bodies is about 3.4 times the mass of our sun. In our galaxy, known binary neutron star systems have connected masses up to only 2.9 times that of the sun.
The study, submitted to The Astrophysical Journal Letters, is authored by an international team comprised of the LIGO Scientific Collaboration and the Virgo Collaboration, the latter of which is associated with the Virgo gravitational-wave detector in Italy.