In 2016, when the twin LIGO detectors made their first historic observation of gravitational waves, astronomers heralded the news both as a confirmation of Einstein’s general relativity and also because, as they love to say, the detection opened a new window on the cosmos.
On January 16, 2018, astrophysicists at Goethe University in Frankfurt, Germany described how they used observations of gravitational waves to answer a question that’s plagued scientists since the 1960s, when they first discovered neutron stars, or stars composed predominantly of closely packed neutrons. By definition, a neutron star has a very small radius and very high density (a teaspoon of neutron star material would weigh about 10 million tons). A typical neutron star mass is about 1.4 suns.
Notice all the abouts in those last couple of sentences? Now, for the first time, astrophysicists have succeeded in putting more precision into those numbers, by calculating a strict upper limit for the maximum mass of neutron stars. They say that, with an accuracy of a few percent, the maximum mass of non-rotating neutron stars cannot exceed 2.16 solar masses.
What happens to a neutron star that does exceed its mass limit? In that case, the neutron star collapses into an even more compressed and vastly more exotic object known as a black hole.
Source - EarthSky.org
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