An Introduction to Modern Astrophysics

Citation

Carroll, B. W., & Ostlie, D. A. (2017). An Introduction to Modern Astrophysics (2nd ed.). Cambridge University Press.

Chapter Summary

The book has thirty chapters in four parts, running to more than 1,200 pages, with appendices of constants, data tables and short computer codes. The Cambridge printing reissues the second edition that Pearson published in 2007. Each chapter is divided into numbered sections with subsection headings, which the authors added so that instructors can skim or omit parts.

Part I, The Tools of Astronomy: Chapters 1–2

Chapter 1, The Celestial Sphere, covers the Greek tradition, the Copernican revolution, positions on the celestial sphere and the relation of physics to astronomy. Chapter 2, Celestial Mechanics, treats elliptical orbits, Newtonian mechanics, a derivation of Kepler's laws and the virial theorem.

Part I: Chapters 3–6

Chapter 3, The Continuous Spectrum of Light, takes up stellar parallax, magnitudes, the wave nature of light, blackbody radiation, the quantization of energy and the colour index. Chapter 4 presents special relativity and Chapter 5 the interaction of light and matter, with spectral lines, photons, the Bohr atom and an introduction to quantum mechanics. Chapter 6, Telescopes, covers basic optics, optical, radio and other-wavelength telescopes and all-sky surveys.

Part II, The Nature of Stars: Chapters 7–9

Chapter 7 uses binary systems to determine stellar parameters and ends with the search for extrasolar planets. Chapter 8 covers the formation of spectral lines, classification of spectra and the Hertzsprung–Russell diagram. Chapter 9, Stellar Atmospheres, treats the radiation field, opacity, radiative transfer, the transfer equation and line profiles.

Chapters 10–11: The Interiors of Stars; The Sun

Chapter 10 develops hydrostatic equilibrium, the equation of state, energy sources, energy transport, model building and the main sequence. Chapter 11 applies this to the Sun: its interior, its atmosphere and the solar cycle.

Chapters 12–14: The Interstellar Medium and Star Formation; Main Sequence and Post-Main-Sequence Stellar Evolution; Stellar Pulsation

Chapter 12 covers interstellar dust and gas, protostars and pre-main-sequence evolution. Chapter 13 follows evolution on and after the main sequence and ends with stellar clusters. Chapter 14 treats observations and physics of pulsating stars, including nonradial pulsation, helioseismology and asteroseismology.

Chapters 15–16: The Fate of Massive Stars; The Degenerate Remnants of Stars

Chapter 15 follows massive stars to supernovae, with the classification of supernovae, core collapse, gamma-ray bursts and cosmic rays. Chapter 16 treats white dwarfs, the physics of degenerate matter, the Chandrasekhar limit, neutron stars and pulsars.

Chapters 17–18: General Relativity and Black Holes; Close Binary Star Systems

Chapter 17 introduces general relativity, intervals and geodesics, and black holes. Chapter 18 returns to binaries: gravity in close systems, accretion disks, interacting binaries, Type Ia supernovae and neutron stars and black holes in binaries.

Part III, The Solar System: Chapters 19–23

Physical processes in the solar system (a survey, tidal forces and the physics of atmospheres) come first, followed by the terrestrial planets, the giant planets with their moons and rings, and minor bodies (Pluto and Charon, comets, Kuiper belt objects, asteroids and meteorites). Chapter 23 treats extrasolar planetary systems and planetary system formation and evolution.

Part IV, Galaxies and the Universe: Chapters 24–26

Chapter 24 describes the Milky Way (star counts, morphology, kinematics and the Galactic center), Chapter 25 the nature of galaxies (the Hubble sequence, spirals and irregulars, spiral structure and ellipticals) and Chapter 26 galactic evolution, through galaxy interactions and formation.

Chapters 27–28: The Structure of the Universe; Active Galaxies

Chapter 27 covers the extragalactic distance scale, the expansion of the universe and clusters of galaxies. Chapter 28 treats observations of active galaxies, a unified model of active galactic nuclei, radio lobes and jets and the use of quasars as probes.

Chapters 29–30: Cosmology; The Early Universe

Chapter 29 develops Newtonian cosmology, the cosmic microwave background, relativistic cosmology and observational cosmology. Chapter 30 closes with the very early universe and inflation, and the origin of structure.

Key Concepts

Part I: Tools (Chapters 1–6)

• Kepler's laws and the virial theorem: results derived from Newtonian mechanics in Chapter 2.
• Blackbody radiation and the magnitude scale: the basic quantities for describing starlight.
• Spectral lines and quantum mechanics: the interaction of light and matter in Chapter 5.

Part II: Stars (Chapters 7–18)

• Hertzsprung–Russell diagram: classification of stars by spectrum and luminosity.
• Radiative transfer and hydrostatic equilibrium: the physics of stellar atmospheres and interiors.
• Degenerate matter and the Chandrasekhar limit: the physics of white dwarfs and neutron stars.
• Accretion disks: the flow of matter in close binary systems.

Parts III–IV: Solar System, Galaxies and Cosmology (Chapters 19–30)

• Tidal forces and planetary atmospheres: the physical processes of Chapter 19.
• Hubble sequence and the extragalactic distance scale: classifying galaxies and measuring distances.
• Unified model of active galactic nuclei: a single picture for several observed classes.
• Cosmic microwave background and inflation: evidence for and a theory of the early universe.

Critical Analysis

Strengths

• Breadth in one book. Four parts cover tools, stars, the solar system, galaxies and cosmology, so a single text can serve a stellar course or a full-year survey, as the authors suggest.
• Modular design. The preface presents the text as a smorgasbord from which instructors select, and says the authors used the first eighteen chapters, with omissions, for a one-semester course in stellar astrophysics.
• Physics-first approach. The authors say the book uses students' physics background and favours back-of-the-envelope calculations from simple models, without simplifying the material beyond recognition. Chapters on special relativity and quantum physics supply the modern physics that the text needs.
• Computing built in. The preface describes computer problems and complete codes for planetary orbits, binary stars, stellar models and galaxy tidal interactions, provided in appendices and for download. The publisher adds worked examples and end-of-chapter problems.

Limitations

• Dated in places. The text of this printing is that of the 2007 second edition. Its preface counts 193 known extrasolar planets and discusses a Kuiper belt object still carrying a provisional designation, so data-driven sections lag current knowledge.
• A very large book. At more than 1,200 pages, no single course covers it; the authors themselves expect instructors to select.
• Comprehensive rather than deep in places. Cosmology receives two chapters (29–30) and stellar interiors one (Chapter 10), so readers wanting more depth on a topic will need a specialist book.
• Mathematical level. The publisher targets astronomy and physics majors with a first-year calculus-based physics course; the authors favour approximate calculations, which means the derivations are not meant to match graduate texts.

Where It Fits in the Course

This is the comprehensive upper-level undergraduate survey in the astrophysics and cosmology course list. Fraknoi, Morrison and Wolff's OpenStax Astronomy 2e is an open introductory text with little mathematics, and Binney's Astrophysics: A Very Short Introduction describes the physical processes behind astronomical objects without advanced mathematics. Maoz's Astrophysics in a Nutshell is a concise one-semester text that derives main results at the level of short derivations and order-of-magnitude estimates, so it suits a quicker, more compact route than Carroll and Ostlie. For cosmology in more depth, Liddle's An Introduction to Modern Cosmology is a short undergraduate introduction to Big Bang cosmology, and Dodelson and Schmidt's Modern Cosmology is the graduate textbook on perturbations and the cosmic microwave background, a natural sequel to Chapters 29–30.

How to Use This Book

The publisher says the book suits astronomy and physics majors who have had a first-year introductory physics course with calculus. The authors say anyone who has had that course can follow nearly all the major concepts, and that Chapters 4 and 5 supply special relativity and quantum physics for those who need them.

A practical plan:

• One-semester stellar course: Chapters 1–3 and 5–6 for the tools, then Chapters 7–13 and selected parts of 14–18, following the authors' own use of the first eighteen chapters.
• Survey of the whole subject: Parts I and II selectively, then Chapters 19–23 for the solar system, 24–28 for galaxies and 29–30 for cosmology. Use the subsection headings to skip.
• Cosmology add-on: Chapters 24–30 can stand as a second course, followed by Liddle or Dodelson and Schmidt.

Work the worked examples, attempt the end-of-chapter problems and try at least one of the computer codes (the orbit and stellar-structure programs are good choices). Use the appendices of constants and data tables for numerical work.