PSR J1614-2230

A massive neutron star, PSR J1614-2230 is also a pulsar that sends out a radio signal each time it spins on its axis at 317 times per second.

What makes this discovery so remarkable is that the existence of a very massive neutron star allows astrophysicists to rule out a wide variety of theoretical models that claim that the neutron star could be composed of exotic subatomic particles such as hyperons or condensates of kaons.

The presence of this extreme star poses new questions about its origin and its nearby white dwarf companion. Did it become so extreme from pulling material from its binary neighbor – or did it simply become that way through natural causes? The neutron star was likely spun up to become a fast-rotating (millisecond) pulsar as a result of the neutron star having cannibalized its stellar companion many millions of years ago, leaving behind a dead core composed mostly of carbon and oxygen.

Although it is common to find a high fraction of stars in binary systems, it is rare for them to be close enough so that one star can strip off mass from its companion star. But when this happens, it is spectacular.