Observing the famous high-mass , eccentric X-ray and \gamma -ray binary PSR B1259–63/LS 2883 with Chandra , we detected X-ray emitting clumps moving from the binary with speeds of \sim 0.1 c , possibly with acceleration .
The clumps are being ejected at least once per binary period , 3.4 yr , presumably around binary periastrons .
The power-law spectra of the clumps can be interpreted as synchrotron emission of relativistic electrons .
Here we report the results of 8 observations of the clumps in 2011-2017 ( two binary cycles ) and discuss possible interpretations of this unique phenomenon .