We present in this talk the first results of the Stardust machine concerning Carbon-chemistry. In evolved stars chemical models have problems to produce abundant C_n species for n>3 due to the presence of many competitive reactions, mainly those producing C2H2, CH4 and C2H4. In our experiments we have observed that the yield of nanoparticules from a cloud of atomic carbon is very low compared to other materials. Our interpretation is based on the difficulty to produce large clusters from small ones due to many forbidden reactions involving small clusters.

We have modelled the formation of C2, C3, and larger carbon clusters, together with silicon-carbon clusters, in the atmosphere of carbon-rich evolved stars and constrasted these models with observations from ALMA, the 30m IRAM telescope. The first results from the stardust machine will be also shown.