Outer Solar System Carbon in the Laboratory

Samples of outer solar system carbon in various forms are available for analysis in the laboratory. The Stardust Mission returned organics and a few carbonate grains from Jupiter Class comet Wild-2 [1]. These complement similar phases available in chondritic interplanetary dust particles, some of which derive from comets, although it is not definitively known which have that origin. Carbonaceous chondrites probably derive from C-complex asteroids which may have outer solar system origins, though this origin is model dependent. There are rare carbonaceous xenoliths in, principally, ordinary chondrites and ureilites whose bulk isotopic and bulk chemical compositions suggest an origin farther from the Sun that the remainder of carbonaceous chondrites [2,3]. These contain abundant carbonaceous materials, including organic-bearing aqueous fluid inclusions [4]. The Hayabusa2 spacecraft recently returned samples of C-class asteroid Ryugu to Earth, now being analyzed in labs worldwide. These materials are expected to be dominated by materials similar to C1 and C2 carbonaceous chondrites [5].