Solar Wind Strips Aliphatic Organics From Asteroid Surfaces, Sparing Aromatics: Study

New laboratory experiments reported in the Journal of Geophysical Research: Planets suggest the solar wind alters asteroid organics unevenly, preferentially destroying aliphatic hydrocarbons while largely sparing aromatic ring structures. Published Oct. 31, 2026, the study led by Futing Yin and Hong Tang used helium ion irradiation to simulate about 800 years of solar wind exposure on a pristine slice of the Murchison carbonaceous meteorite. The treatment increased structural disorder in the meteorite’s macromolecular organic network and reduced total organic abundance, with aliphatic C–H groups suffering the biggest losses. The result implies that reflectance spectra from C-type asteroids may undercount aliphatic organic content present before solar wind processing.