ИСТИНА

According to a traditional point of view, asteroids of the main belt originated in the early Solar System (ESS) in situ, due to collisional disruption of asteroid parent bodies (APBs) [1]. Very close positions of heliocentric distributions of igneous and primitive asteroid types may be explained by zoning action of APBs’ heating by the short-lived radionuclides (generally 26Al) [2]. But this structure could also be distorted by other factors. As modeling show, the heating was less on APBs which accumulated some water ice in the outer asteroid belt [2]. Melting water ice in interiors of such APBs would lead to formation of a temporal aqueous medium. For the same reasons, extensive internal water oceans could form and exist for some time on many rock-ice bodies in the ESS outside the "snow-line". Internal water oceans on Edgeworth-Kuiper objects (EKOs)[3] and a great number of proto-planetary bodies in the formation zones of giant planets were probably additional sources of icy and/or rock-icy fragments after breaking up the bodies at collisions. Intensive fluxes of the materials might have considerably influence chemical and mineralogical content of APBs at the time of their accretion and shortly thereafter. References: [1] Bell J. F., et al. (1989), in Asteroids II (eds Binzel R. P., Gehrels T., Matthews M. S.), Tucson: Univ. Arizona Press, 921. [2] Grimm R. E., McSween H. Y. (1989) Icarus, 82, 248. [3] Busarev V. V. et al. (2003), Earth, Moon & Planets, 92, 345.