The Formation of Stars

Abstract

Preface. I Star Formation in Our Galaxy. 1 Overview. 1.1 Stellar Nurseries: Orion. 1.2 Stellar Nurseries: Taurus-Auriga. 1.3 Stars and Their Evolution. 1.4 The Galactic Context. 2 The Interstellar Medium. 2.1 Galactic Gas and Its Detection. 2.2 Phases of the Interstellar Medium. 2.3 Interstellar Dust: Extinction and Thermal Emission. 2.4 Interstellar Dust: Properties of the Grains. 3 Molecular Clouds. 3.1 Giant Molecular Clouds. 3.2 Virial Theorem Analysis. 3.3 Dense Cores and Bok Globules. 4 Young Stellar Systems. 4.1 Embedded Clusters. 4.2 T and R Associations. 4.3 OB Associations. 4.4 Open Clusters. 4.5 The Initial Mass Function. II Physical Processes in Molecular Clouds. 5 Molecular Transitions: Basic Physics. 5.1 Interstellar Molecules. 5.2 Hydrogen (H2). 5.3 Carbon Monoxide (CO). 5.4 Ammonia (NH3). 5.5 Water (H2O). 5.6 Hydroxyl (OH). 6 Molecular Transitions: Applications. 6.1 Carbon Monoxide. 6.2 Ammonia. 6.3 Hydroxyl. 7 Heating and Cooling. 7.1 Cosmic Rays. 7.2 Interstellar Radiation. 7.3 Cooling by Atoms. 7.4 Cooling by Molecules and Dust. 8 Cloud Thermal Structure. 8.1 The Buildup of Molecules. 8.2 The Molecular Interior. 8.3 Photodissociation Regions. 8.4 J-Shocks. 8.5 C-Shocks. III From Clouds to Stars. 9 Cloud Equilibrium and Stability. 9.1 Isothermal Spheres and the Jeans Mass. 9.2 Rotating Configurations. 9.3 Magnetic Flux Freezing. 9.4 Magnetostatic Configurations. 9.5 Support from MHD Waves. 10 The Collapse of Dense Cores. 10.1 Ambipolar Diffusion. 10.2 Inside-Out Collapse. 10.3 Magnetized Infall. 10.4 Rotational Effects. 11 Protostars. 11.1 First Core and Main Accretion Phase. 11.2 Interior Evolution: Deuterium Burning. 11.3 Protostellar Disks. 11.4 More Massive Protostars. 11.5 The Observational Search. 12 Multiple Star Formation. 12.1 Dynamical Fragmentation of Massive Clouds. 12.2 Young Binary Stars. 12.3 The Origin of Binaries. 12.4 Formation of Stellar Groups. 12.5 Massive Stars and Their Associations. IV Environmental Impact of Young Stars. 13 Jets and Molecular Outflows. 13.1 Jets from Embedded Stars. 13.2 Molecular Outflows. 13.3 Wind Generation: Pressure Effects. 13.4 Wind Generation: Rotation and Magnetic Fields. 13.5 Jet Propagation and Entrainment. 14 Interstellar Masers. 14.1 Observed Characteristics. 14.2 Maser Theory: Basic Principles. 14.3 Maser Theory: Further Considerations. 14.4 Tracing Jets and Outflows. 15 Effects of Massive Stars. 15.1 HII Regions. 15.2 Ultracompact HII Regions and Hot Cores. 15.3 Winds and Molecular Outflows. 15.4 Photoevaporation of Gas. 15.5 InducedStar Formation. V Pre-Main-Sequence Stars. 16 Quasi-Static Contraction. 16.1 The Stellar Birthline. 16.2 The Contraction Process. 16.3 Nuclear Reactions. 16.4 Brown Dwarfs. 16.5 Spinup and Spindown. 17 T Tauri Stars. 17.1 Line and Continuum Emission. 17.2 Outflow and Infall. 17.3 Circumstellar Disks. 17.4 Temporal Variability. 17.5 Post-T Tauri Stars and Beyond. 18 Herbig Ae/Be Stars. 18.1 Basic Properties. 18.2 Nonhomologous Evolution. 18.3 Thermal and Mechanical Effects. 18.4 Gaseous and Debris Disks. VI A Universe of Stars. 19 Star Formation on the Galactic Scale. 19.1 The Milky Way Revisited. 19.2 Other Galaxies. 19.3 The Starburst Phenomenon. 19.4 Galaxies in Their Youth. 19.5 The First Stars. 20 The Physical Problem: A Second Look. 20.1 Clouds. 20.2 Stars. 20.3 Galaxies. Appendices. A Astronomical Conventions. A.1 Units and Constants. A.2 Photometric Systems. A.3 Equatorial and Galactic Coordinates. B The Two-Level System. C Transfer of Radiation in Spectral Lines. D Derivation of the Virial Theorem. E Spectral Line Broadening. E.1 Natural Width. E.2 Thermal, Turbulent, and Collisional Broadening. E.3 Rotational Broadening of Stellar Lines. E.4 Two Examples: H2 and CO in Clouds. F Shock Jump Conditions. G Radiative Diffusion and Stellar Opacity. H Derivation of Binary Star Relations. I Evaluation of a Polytropic Integral. Sources for Tables, Figures, and Plates. Index of Astronomical Objects. Subject Index.