Table of Contents
List of Figures xiii
Preface xix
I Introduction and Phenomenology 1
1 Observing the Cold Interstellar Medium 3
1.1 Observing Techniques 3
1.2 Observational Phenomenology 18
2 Observing Young Stars 23
2.1 Individual Stars 23
2.2 Statistics of Resolved Stellar Populations 30
2.3 Unresolved Stellar Populations and Extragalactic Star Formation 33
II Physical Processes 43
3 Chemistry and Thermodynamics 45
3.1 Chemical Processes in the Cold ISM 45
3.2 Thermodynamics of Molecular Gas 54
4 Gas Flows and Turbulence 63
4.1 Characteristic Numbers for Fluid Flow 63
4.2 Modeling Turbulence 67
4.3 Supersonic Turbulence 72
Problem Set 1 79
5 Magnetic Fields and Magnetized Turbulence 83
5.1 Observing Magnetic Fields 83
5.2 Equations and Characteristic Numbers for Magnetized Turbulence 87
5.3 Non-Ideal Magnetohydrodynamics 91
6 Gravitational Instability and Collapse 99
6.1 The Virial Theorem 99
6.2 Stability Conditions 104
6.3 Pressureless Collapse 115
7 Stellar Feedback 121
7.1 General Formalism 121
7.2 Momentum-Driven Feedback Mechanisms 126
7.3 (Partly) Energy-Driven Feedback Mechanisms 130
III Star Formation Processes and Problems 141
8 Giant Molecular Clouds 143
8.1 Molecular Cloud Masses 144
8.2 Scaling Relations 153
8.3 Molecular Cloud Timescales 157
Problem Set 2 157
9 The Star Formation Rate at Galactic Scales: Observations 171
9.1 The Star Formation Rate Integrated Over Whole Galaxies 172
9.2 The Spatially-Resolved Star Formation Rate 178
9.3 Star Formation in Dense Gas 187
10 The Star Formation Rate at Galactic Scales: Theory 193
10.1 The Top-Down Approach 194
10.2 The Bottom-Up Approach 203
11 Stellar Clustering 215
11.1 Observations of Clustering 215
11.2 Theory of Stellar Clustering 223
12 The Initial Mass Function: Observations 233
12.1 Resolved Stellar Populations 234
12.2 Unresolved Stellar Populations 245
12.3 Binaries 249
Problem Set 3 253
13 The Initial Mass Function: Theory 257
13.1 The Power Law Tail 257
13.2 The Peak of the IMF 263
14 Protostellar Disks and Outflows: Observations 275
14.1 Observing Disks 276
14.2 Observations of Outflows 285
15 Protostellar Disks and Outflows: Theory 289
15.1 Disk Formation 289
15.2 Disk Evolution 296
15.3 Outflow Launching 310
16 Protostar Formation 317
16.1 Thermodynamics of a Collapsing Core 317
16.2 The Protostellar Envelope 325
17 Protostellar Evolution 333
17.1 Fundamental Theory 333
17.2 Evolutionary Phases for Protestars 342
17.3 Observable Evolution of Protostars 349
Problem Set 4 357
18 Massive Star Formation 361
18.1 Observational Phenomenology 362
18.2 Fragmentation 367
18.3 Barriers to Accretion 372
19 The First Stars 381
19.1 Cosmological Context 382
19.2 Chemistry and Thermodynamics of Primordial Gas 383
19.3 The IMF of the First Stars 388
19.4 The Transition to Modern Star Formation 391
20 Late-Stage Stars and Disks 399
20.1 Stars Near the End of Star Formation 399
20.2 Disk Dispersal: Observation 405
20.3 Disk Dispersal: Theory 409
21 The Transition to Planet Formation 419
21.1 Dynamics of Solid Particles in a Disk 419
21.2 From Pebbles to Planetesimals 425
Problem Set 5 435
A Statistical Mechanics of Multi-Level Atoms and Molecules 439
A.1 Matter-Radiation Interaction 439
A.2 Statistical Equilibrium for Multi-Level Systems 442
A.3 Critical Densities for Multi-Level Systems 444
B Solutions to Problem Sets 447
Solutions to Problem Set 1 449
Solutions to Problem Set 2 452
Solutions to Problem Set 3 463
Solutions to Problem Set 4 472
Solutions to Problem Set 5 485
Bibliography 495
Index 503
