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37 lines
1.1 KiB
Plaintext
37 lines
1.1 KiB
Plaintext
Homework 12, due Oct 5
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1) For the kinetic temperatures of a cluster of galaxies, T=3x10⁷ K, and for the Orion H II region, T=10⁴ K, what energy in eV does it correspond to?
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T 3x10⁷ K 10⁴ K
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Eₖₜ 2585.2 eV 0.86173 eV
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2) What is the closest ionization stage of the six most common elements for those two temperatures, considering just the ionization energy?
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Cluster Orion
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Thermal Average Energy
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────────────────────────
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2585.2 eV 0.86173 eV
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Near Ionization Stage
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────────────────────────
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H I H I
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He II He I
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O VIII O I
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C VI C I
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Ne X Ne I
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Fe XXIV Fe I
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We expect all of the elements to be ionized in the cluster, except iron.
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3) Consider the very important case of H 2 , H 0 , and H + . What is the temperature needed to dissociate H 2 and form H 0 , and then to ionize H 0 ?
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H₂[zero point] = -4.5 eV.
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4.5 eV / kᵦ = 5.2×10⁴ K.
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H⁰[zero point] = 13.6 eV.
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13.6 / kᵦ = 1.58×10⁶ K. |