X-ray rings reveal neutron star’s distance
Dust cloud reflections plus trigonometry puts Circinus X-1 at 31,000 light-years away
![blast of X-rays from a neutron star](https://i0.wp.com/www.sciencenews.org/wp-content/uploads/2015/06/cc_xrayhalo_free.jpg?fit=860%2C460&ssl=1)
BULL’S-EYE A blast of X-rays from a neutron star (center) illuminate dust clouds between the star and Earth (colored rings), as seen in this composite image. Red, green and blue correspond to low-, medium- and high-energy X-rays.
S. Heinz et al/U. of Wisconsin–Madison/CXC/NASA (X-ray); DSS (optical)