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Abstract— We determined He, Ne, Ar, 10 Be, 26 Al, 36 Cl, and 14 C concentrations, as well as cosmic‐ray track densities and halogen concentrations in different specimens of the H6 chondrite Torino, in order to constrain its exposure history to cosmic radiation. The Torino meteoroid had a radius of ∼20 cm and travelled in interplanetary space for 2.5–10 Ma. Earlier, Torino was part of a larger body. The smallest possible precursor had a radius of 55 cm and a journey through space longer than ∼65 Ma. If the first‐stage exposure took place in a body with a radius of >3 m or in the parent asteroid, then it lasted nearly 300 Ma. The example of Torino shows that it is easy to underestimate first‐stage exposure ages when constructing two‐stage histories.
Wieler et al. (Fri,) studied this question.