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.
“We naively thought Pluto might be losing its atmosphere at the same rate as [some] comets,” says Carey Lisse, a planetary astronomer at the Applied Physics