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О возможном источнике углисто-хондритового и предбиологического веществастатья
- Автор: Бусарев В.В.
- Сборник: Труды рабочего совещания-дискуссии "Активность звезд и Солнца на разных стадиях их эволюции", 17-18 декабря 2010, ГАИШ МГУ, Москва, (под ред. В.Н. Обридко и Ю.А. Наговицына), Астрономическое о-во, С.-Петербург
- Год издания: 2011
- Место издания: Астрономическое общество С.-Петербург
- Первая страница: 205
- Последняя страница: 218
- Аннотация: For the limiting case of the rapid formation of Edgeworth-Kuiper objects (EKOs) for about 1.5 Myr after the collapse of the protosolar cloud in the early Solar system (ESS), the possibility of existence of internal water ocean in these bodies due to 26Al decay was analytically shown [19]. The lifetime of the liquid water ocean was estimated to be about 2 to 5 Myr for the bodies 200 to 600 km before complete freezing. If the parent material of EKOs similarly to comet nuclei consisted of a conglomerate of ice and dust particles (the so called “dirty ice”), sedimentation of solid particles of silicates and heavy organics (of kerogen or bitumen type) in the water ocean (leading to a core accumulation) was accompanied by formation of phyllosilicates and prebiotic compounds. During this time, only a surface layer with a thickness of ~10 km could remain frozen on the large EKOs. Similar rock-icy bodies should have existed in the formation zones of all giant planets at the first stage of their accretion: solid-body accumulation phase, which lasted for 1 to 2 Myr in the Jupiter to Saturn formation zones. Along with heating these bodies by 26Al decay, intensive mutual collisions provided their additional heating. Then lifetimes of liquid water oceans, for instance, in large Jupiter zone bodies (JZBs) may be estimated as ~10 Myr before freezing. If these bodies were not devoured by the embryo of Jupiter, they had been thrown by it out of the zone at high relative velocities (2-3 to ~30 km s-1), in particular, to the main asteroid belt (MAB), where they could collide rocky asteroid parent bodies (APBs). Low strength and high fragility of JZBs (especially during existence of an internal water ocean) were reasons of their predominant crushing at collisions with more strong APBs. Largest fragments of JZBs and similar bodies from the formation zones of other giant planets remained probably in the MAB adding to the families of primitive asteroids (e. g., C, D, and P types). The debris and dust could preserve the predominant direction of velocity of their parent bodies (e. g., JZBs) and move inwards the ESS. Velocities of the debris could effectively decrease in gas environment of the ESS. It was probably the main reason of safe fall of the low-temperature materials (water ice, hydrated silicates and refractory organics) onto the surfaces of close APBs. We suggest reaccretion of the grinded carbonaceous and prebiotic matter accumulated in the internal water oceans of rock-icy bodies at the time of their early thermal evolution as a possible mechanism of formation of all types of carbonaceous chondrites on APBs.
- Добавил в систему: Бусарев Владимир Васильевич