cosmochemistry

Layer 2 — Chemistry24 concepts in this subtree

Cosmochemistry — IUPAC-VII applied chemistry at the meteorite / interplanetary-dust / stellar-condensate grain. Foundations: the terrestrial-fractionation line (TFL) δ¹⁷O = 0.52 · δ¹⁸O (slope set by mass-dependent kinetic/equilibrium…

Mass-dependent fractionation line δ¹⁷O = 0.52·δ¹⁸O (TFL anchor)
R_mix = f·R_A + (1−f)·R_B: linear 2-component isotope mixing
ln(P₂/P₁) = −(L/R)·(1/T₂ − 1/T₁): condensation-T curves for refractories
Δ¹⁷O = δ¹⁷O − 0.52·δ¹⁸O; zero on TFL (mass-dependent samples)
R_mix at f=0 ⇒ R_B, f=1 ⇒ R_A, f=1/2 ⇒ (R_A+R_B)/2
r-process peaks sum N=50+82+126 = 258 (closed-shell magic-N anchor)
s-process framework: σ·N = const along s-only path (slow neutron capture local equilibrium)
Hoyle triple-α framework: 3 α → ¹²C via A=8 ⁸Be resonance; Q ≈ 7.65 MeV
CNO bicycle framework: 4p → α + 2e⁺ + 2ν_e; CNO catalysts (C, N, O) conserved modulo cycle
s-process σ·N = const: N₂/N₁ = σ₁/σ₂ (canonical invariant along s-only path)
Hoyle 3α → ¹²C: α-count 3; Q ≈ 7.654 MeV (3827/500); A=8 bottleneck gap
CNO bicycle: 4 p consumed / 1 α produced per cycle; CNO catalysts net = 0
Origin of biological homochirality (open question)
CAI dating (Bondard 2002)
Snow line (Hayashi 1981)
B2FH (Burbidge 1957)
ISM organics (Snyder 1969)
Murchison amino acids
Urey (1952)
Anders-Grevesse abundances
CAIs (Allende meteorite)
Rosetta 67P (2014)
Hayashi snow-line (1981)
Interstellar glycine (2009)
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