Here's how tricky it is to look into the heart of a neutron star: It requires bending space and time to do it.
Astronomers and physicists are deeply interested in these collapsed stars, since they offer a look at extreme conditions just short of the impenetrable barriers of a black hole. Neutron stars are formed by the collapse of an ordinary star, often after a supernova, into an incredibly dense, cold object.
This process pushes the remaining matter in the star so closely together that a cup of neutron star material would weigh more than Mount Everest, scientists say. But it's not yet clear exactly what that material is.
However, a new study by astronomers at the University of Michigan and NASA's Goddard Space Flight Center, using European and Japanese space-based X-ray observatories is offering a valuable new approach to this question
The researchers are studying celestial pairs containing a neutron star and a more ordinary companion. They've observed spectral lines created by iron atoms whirling around the denser members of the pairs at rates close to 40 percent of the speed of light.
Thanks to Einstein's general theory of relativity, they also understand that the incredibly dense neutron stars are bending space and time in their near vicinities, shifting the radiation emitted by these iron atoms to longer wavelengths, somewhat like the sound of a train getting deeper as it recedes.
Researchers are then able to use this information to help estimate the collapsed stars' size and masses, which can in turn help them understand the state of matter inside the star itself.
The procedure provides yet another striking verification of
Einstein's predictions of space-time distortion. But the observations should provide another helpful tool in understanding what happens to matter under some of the most extreme conditions in the universe.
From the announcement:
(Photo: Artist's depiction of a rare explosion on a neutron star. Credit: NASA/Dana Berry)
