Round 9: Tossup 16
A specific form of this process that occurs for about a day maintains a state of quasi-equilibrium but not true statistical equilibrium. This process defines a stellar timescale whose numerator has a 0.007 coefficient, and is around 10-to-the-4th that of the Kelvin–Helmholtz timescale. Different mechanisms for this physical process have temperature dependencies of T-to-the-17 and T-to-the-41. In the Gamow window, this process is enhanced by quantum tunneling through the Coulomb barrier. This process progressively begins in increasingly outward shells, forming an onion-like structure, during evolution of massive stars. This process occurs to hydrogen through the CNO cycle and the proton–proton chain. For 10 points, name this process that powers stars, in which two nuclei combine to form a larger nucleus. ■END■
ANSWER: thermonuclear fusion [accept nucleosynthesis; accept burning or answers referring to burning of specific elements like hydrogen burning or silicon burning; accept triple alpha process; accept proton–proton chain or CNO cycle until read; prompt on nuclear reactions or nuclear timescale or nuclear statistical equilibrium; reject “combustion”] (The first sentence refers to nuclear quasi-equilibrium in silicon burning.)
<GC, Other Science> | Packet H - Yale A, Ohio State C, Illinois C, Virginia Tech B, MIT A
= Average correct buzzpoint
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