Book contents
- Frontmatter
- Contents
- Preface to the First Edition
- Preface to the Second Edition
- Acknowledgments
- Prologue
- Chapter 1 A brief history
- Chapter 2 The universe
- Chapter 3 Stars
- Chapter 4 The solar nebula
- Chapter 5 Composition and chemical evolution of the solar nebula
- Chapter 6 The evidence from meteorites
- Chapter 7 Building planets
- Chapter 8 The giant planets
- Chapter 9 Satellites and rings
- Chapter 10 The refugees
- Chapter 11 The survivors: Mercury and Mars
- Chapter 12 The twins: Venus and the Earth
- Chapter 13 The Moon
- Chapter 14 The role of impacts
- Chapter 15 Epilogue: on the difficulty of making Earth-like planets
- Name index
- Subject index
Chapter 5 - Composition and chemical evolution of the solar nebula
Published online by Cambridge University Press: 05 June 2012
- Frontmatter
- Contents
- Preface to the First Edition
- Preface to the Second Edition
- Acknowledgments
- Prologue
- Chapter 1 A brief history
- Chapter 2 The universe
- Chapter 3 Stars
- Chapter 4 The solar nebula
- Chapter 5 Composition and chemical evolution of the solar nebula
- Chapter 6 The evidence from meteorites
- Chapter 7 Building planets
- Chapter 8 The giant planets
- Chapter 9 Satellites and rings
- Chapter 10 The refugees
- Chapter 11 The survivors: Mercury and Mars
- Chapter 12 The twins: Venus and the Earth
- Chapter 13 The Moon
- Chapter 14 The role of impacts
- Chapter 15 Epilogue: on the difficulty of making Earth-like planets
- Name index
- Subject index
Summary
The great mixture of ingredients that were in the original disk and from which the Sun and planets were built, can be reduced to three basic components: gas, ice and rock (Fig. 5.1). The gas was mostly hydrogen and helium that made up 98% of the mass of the initial solar nebula. The remaining 2% of material in the nebula consisted of various ices and rock composed of the heavier elements. The ices can be divided into three groups[1]. Water ice is the dominant component and displays many polymorphs. Other ices are more volatile and include NH3, CO2 and methanol (CH3OH). A “super-volatile” group includes methane (CH4), CO and N2 that, in contrast to the former group, do not form phases with water.
Volatility is the most important chemical parameter under nebular conditions, so the elements present as “rock” are classified as “very volatile” (e.g., Bi, Tl); “volatile” (e.g., K, Rb, Cs); “moderately volatile” (e.g., Mn, Ba, Sr); “moderately refractory” (e.g., Si, Fe, Mg, Cr, V, Eu); “refractory” (e.g., Ca, Al, U, La), and “super-refractory” (e.g., Zr) (Table 5.1). Elements are also classified as lithophile, chalcophile or siderophile according to their preference for entering silicate, sulfide or metal (Fe) phases.
The term “solar-system abundances” refers to the composition of the solar system, including the Sun.
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- Solar System EvolutionA New Perspective, pp. 73 - 104Publisher: Cambridge University PressPrint publication year: 2001
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