Sulfuric acid as a corrosive cryofluid and oxygen isotope reservoir in planetesimals

The Sun exhibits a depletion in $^{17,18}$O relative to $^{16}$O by 6 % compared the Earth and Moon$^{1}$. origin of such non-mass-dependent isotope fractionation has been extensively debated since three-isotope-analysis$^{2}$ became available 1970's. Self-shielding$^{3,4}$ CO molecules against UV photons solar system's parent molecular cloud suggested as source effect, which $^{17,18}$O-enriched oxygen was trapped ice selectively incorporated water into planet-forming materials$^{5}$. truth is that Earth-Moon other planetary objects deviate positively from ~6 their isotopic compositions. A stunning exception magnetite/sulfide symplectite found Acfer 094 meteorite, shows 24 enrichment Sun$^{6}$. Water does not explain this high. Here we show SO SO$_2$ cloud, ~106 enriched Sun, evolved through protoplanetary disk planetesimal stages become sulfuric acid, $^{17,18}$O. acid provided cryofluid environment itself reacted with ferric iron form an amorphous ferric-hydroxysulfate-hydrate, eventually decomposed shock. We indicate Acfer-094 its progenitor, strongly coupled material evolution system days our cloud.