Despite wrong conditions, handful-plus of photons detected streaming from dwarf planet
X-ray: NASA, CXC, JHUAPL, R.McNutt et al; Optical: NASA, JHUAPL
X-rays appear to be trickling away from Pluto, even though the dwarf planet has no obvious way of making the high-energy photons, a new study reports.
Given what researchers have learned about Pluto since the New Horizons spacecraft flew by in 2015 (SN: 8/8/15, p. 6), the discovery is surprising. For many planets and comets, X-rays are generated when the solar wind, a stream of charged particles from the sun, runs into neutral gas atoms or magnetic fields from these bodies. But the environment around Pluto isn’t conducive to producing X-rays: the dwarf planet has no measurable magnetic field, its atmosphere is very thin, and it’s losing that atmosphere at rates much lower than expected.