Tag Archives: Neutron Stars

Neutron Stars Discovered on Collision Course

Neutron Stars Discovered on Collision Course
By: AAS Nova | March 8, 2018
Sky and Telescope Magazine

Got any plans in 46 million years? If not, you should keep an eye out for PSR J1946+2052 around that time this upcoming merger of two neutron stars promises to be an exciting show!

Artist’s illustration of the final stages of a neutron-star merger. Scientists have now caught a binary-neutron-star system about 46 million years before this stage. NASA/Goddard Space Flight Center


It seems like we just wrote about the dearth of known double-neutron-star systems, and about how new surveys are doing their best to find more of these compact binaries. Observing these systems improves our knowledge of how pairs of evolved stars behave before they eventually spiral in, merge, and emit gravitational waves that detectors like the Laser Interferometer Gravitational-wave Observatory (LIGO) might observe.

Today’s study, led by Kevin Stovall (National Radio Astronomy Observatory), goes to show that these surveys are doing a great job so far! Yet another double-neutron-star binary, PSR J1946+2052, has now been discovered as part of the Arecibo L-Band Feed Array pulsar (PALFA) survey. This one is especially unique due to the incredible speed with which these neutron stars orbit each other and their correspondingly (relatively!) short timescale for merge

LIGO Detects a Neutron Star Merger

New LIGO discovery is an astronomer’s dream come true.

On August 17, astronomers detected gravitational waves and a gamma-ray burst from two colliding neutron stars. National Science Foundation/LIGO/Sonoma State University/A. Simonnet

On August 17, Mother Nature delivered a gift to astronomers as precious as anything they could have imagined: gravitational waves from two neutron stars spiraling inward and merging, followed moments later by a burst of gamma rays from the same patch of sky. This cosmic double whammy was officially announced today after nearly two months of rumors. It proves a long-standing theory for an enigmatic class of cosmic cataclysms while heralding a revolutionary new era of multi-messenger astronomy.

The sequence of events started at 8:41 a.m. Eastern time when a train of gravitational waves started rolling through the Virgo detector near Pisa, Italy. The same waves rumbled through the LIGO detector in Livingston, Louisiana, just 22 milliseconds later, then the twin LIGO detector in Hanford, Washington, 3 milliseconds after that.

The LIGO and Virgo instruments detected a crescendo of waves for a whopping 100 seconds — much longer than previous detections. The duration, amplitude, and frequency of the waves had all the characteristics that theorists have expected for a binary system consisting of two neutron stars on a death spiral ending with coalescence. The two neutron stars had masses of about 1.5 and 1.1 solar masses, respectively. About 1 to 2 percent of that mass was likely ejected into space during the merger, which presumably resulted in a black hole of nearly 3 solar masses, although the LIGO data does not prove that a black hole formed. If a black hole indeed formed, it’s the lightest black hole yet known.