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Appendix I Constants

Constant Symbol Value Universal constants in vacuum c 2.9979 9 108 ms-1 Universal G 6.674 9 10-11 Nm2 kg-2 6.674 9 10-11 m3 kg-1 s-2 h 6.6261 9 10-34 Js -12 -1 Electric constant e0 8.8542 9 10 Fm -6 -2 Magnetic constant l0 1.2566 9 10 NA Thermal radiation k 1.38065 9 10-23 JK-1 Stefan-Boltzmann constant r 5.6704 9 10-8 Js-1 m-2 K-4 Radiation density constant a 7.5657 9 10-16 Jm-3 K-4 Wien displacement law constant b 2.8978 9 10-3 mK Atomic and nuclear -31 mass me 9.1094 9 10 kg e 1.6022 9 10-19 C -15 Classical electron radius re 2.8179 9 10 m -29 2 Thomson scattering cross section rT 6.65246 9 10 m -27 Atomic mass unit mu = u 1.660539 9 10 kg -27 Proton mass mp 1.6726 9 10 kg -27 Neutron mass mn 1.6749 9 10 kg -27 Alpha particle mass ma 6.644656 9 10 kg -11 a0 5.2918 9 10 m -1 Rydberg constant R? 10,973,731.5685 m 30 Mass of the Sun M 1.989 9 10 kg 26 -1 Luminosity of Sun L 3.828 9 10 Js 8 Radius of Sun R 6.955 9 10 m Expanding universe -1 -1 Hubble constant H0 75 km s Mpc 9 Age of expanding Universe t0 13.7 9 10 years (continued)

K. R. Lang, Essential Astrophysics, Undergraduate Lecture Notes in Physics, 607 DOI: 10.1007/978-3-642-35963-7, Ó Springer-Verlag Berlin Heidelberg 2013 608 Appendix I Constants

(continued) Constant Symbol Value Cosmic microwave background radiation

Temperature TCMB 2.725 K 8 -3 Photon density NCMB 4.10 9 10 m -5 Anisotropy DT=TCMB 1.1 9 10 The physical constants are accurate to the fourth decimal place. For greater accuracy with the latest values consult http://physics.nist.gov/cuu/constants/index.html Appendix II Units

Unit Symbol Value Distance and length Ångström Å 10-10 m Meter m 1 km = 103 m = 0.621371 mile 1 mile = 1.60934 km Mean Earth-Sun AU 1.49598 9 1011 m distance Light-year ly 9.460528 9 1015 m = 63,239.67 AU Parsec pc 3.08568 9 1016 m = 3.26164 light- years = 206,265 AU Megaparsec Mpc 106 pc Angle Degree ° 600 = 360000 1° = 0.0174532925 radians 100 = 4.8481368 9 10-6 radians (The symbol 0 denotes minutes of arc, the symbol 00 designates seconds of arc) Radian rad 2.06265 9 105 00 57.2957795° = 360°=(2p) Pi p 3.141592654 Time Solar day day 24 h = 86,400 s Sidereal day sidereal day 23 h 56 m 04.09 s = 23.9344696 h Year tropical 365.25 solar days = 3.15576 9 107 s year Energy, power, force, pressure Joule J 107 erg Electron-volt ev 1.6018 9 10-19 J Power Watt J s-1 Force N kg m s-2 Pressure Pa N m-2 (continued)

K. R. Lang, Essential Astrophysics, Undergraduate Lecture Notes in Physics, 609 DOI: 10.1007/978-3-642-35963-7, Ó Springer-Verlag Berlin Heidelberg 2013 610 Appendix II Units

(continued) Unit Symbol Value Mass Kilogram kg 1,000 g, 1 metric ton = 103 kg Solar units 30 Mass of the Sun M 1.989 9 10 kg 26 -1 Luminosity of Sun L 3.828 9 10 Js 8 Radius of Sun R 6.955 9 10 m Appendix III Fundamental Equations

Angular resolution, hr, of a telescope of diameter, DT, at a wavelength, k: k hr ¼ radians ðA-1Þ DT where 1 radian = 2.06265 9 105 seconds of arc = 2.06265 9 105 00.

Angular source extent, hsize, of a celestial source of radius, R, located at a distance, D: 2R h ¼ radians; ðA-2Þ size D where 1 radian = 2.06265 9 105 seconds of arc = 2.06265 9 105 00. Wavelength, k, frequency, m, and speed of light, c: k m ¼ c; ðA-3Þ where the speed of light c = 2.9979 9 108 ms-1. Photon energy, E, of radiation at frequency m: E ¼ hm ðA-4Þ where the Planck constant h = 6.6261 9 10-34 Js. Stefan-Boltzmann law for luminosity, L, of thermal radiator with effective Teff and radius R: 2 4 L ¼ 4prR Teff ðA-5Þ where p = 3.14159 and the Stefan-Boltzmann constant r = 5.6704 9 10-8 Js-1 m-2 K-4. Apparent magnitude, absolute magnitude, and luminosity for a . Any apparent magnitude, m, can be converted to absolute magnitude, M, through the simple formula:

K. R. Lang, Essential Astrophysics, Undergraduate Lecture Notes in Physics, 611 DOI: 10.1007/978-3-642-35963-7, Ó Springer-Verlag Berlin Heidelberg 2013 612 Appendix III Fundamental Equations

absolute magnitude ¼ M ¼ m þ 5 5log D; ðA-6Þ where D is the distance in parsecs, and 1 parsec = 3.26164 light- years = 3.08568 9 1016 m. The absolute magnitude can be converted into a luminosity, L, using: L log ¼ 0:4ðÞM M ; ðA-7Þ L or

0:4ðMMÞ L ¼ 10 L; ðA-8Þ where the absolute magnitude of the Sun in the visual range of , where it is most intense, is M = +4.83 and the absolute luminosity of the Sun is 26 -1 L = 3.828 9 10 Js . Notice that the symbol M is used to denote both the absolute magnitude of the Sun, which is used here, and the mass of the Sun, used in other equations. The Sun has an apparent magnitude of m =-26.74.

Wien displacement law for wavelength kmax of maximum intensity for a thermal radiator at temperature T: 0:002898 k ¼ meters: ðA-9Þ max T

Radiant flux, f,orapparent brightness, of an object of luminosity L at distance D: L f ¼ : ðA-10Þ 4pD2

Gravitational force, FG, between two masses, M1 and M2 separated by a distance D between their centers: GM M F ¼ 1 2 ; ðA-11Þ G D2 where the universal gravitational constant G = 6.674 9 10-11 m3 kg-1 s-2.

Kepler’s third law for the P of a binary system of mass M1 and M2 separated by distance a: 4p2 P2 ¼ a3 ðA-12Þ GMðÞ1 þ M2 Appendix III Fundamental Equations 613 where the universal gravitational constant G = 6.674 9 10-11 m3 kg-1 s-2.

Jeans mass, MJ, for a spherical cloud of radius, R, and temperature, T: 3kT M ¼ R; ðA-13Þ J Gm where the Boltzmann constant k = 1.38065 9 10-23 JK-1, the universal gravitational constant G = 6.674 9 10-11 m3 kg-1 s-2, and m is the gas particle mass. Gravitational collapse occurs if the cloud mass, M, is greater than the Jeans mass, MJ.

Escape velocity, Vesc, at a distance R from a mass M: 2GM 1=2 V ¼ ; ðA-14Þ esc R where the universal gravitational constant G = 6.674 9 10-11 m3 kg-1 s-2.

Doppler effect for a change Dk in the wavelength k due to a Vr of a source moving away from observer:

Dk kobserved kemitted Vr ¼ ¼ for Vr c; ðA-15Þ kemitted kemitted c where the speed of light c = 2.9979 9 108 ms-1.

Parallax the annual parallax pA, of a star at distance, D, is:

pA ¼ AU=D radians; ðA-16Þ where 1 AU = 1.49598 9 1011 m and 1 radian = 2.06265 9 105 s of arc. When the parallax is given in units of seconds of arc, then the distance, D, is given by: 1 D ¼ parsecs; ðA-17Þ pA where 1 parsec = 3.26164 light years = 206,265.8 AU. Gravitational potential energy of a mass, M, with radius, R: GM2 Gravitational potential energy ¼ ; ðA-18Þ R where the universal gravitational constant G = 6.674 9 10-11 m3 kg-1 s-2. Kinetic energy of mass, m, moving at velocity, V: 1 Kinetic energy ¼ mV2 : ðA-19Þ 2 Thermal energy at temperature, T: 3 Thermal energy ¼ kT; ðA-20Þ 2 614 Appendix III Fundamental Equations where the Boltzmann constant k = 1.38065 9 10-23 JK-1.

Thermal velocity, Vthermal, of a particle of mass, m, at temperature, T: rffiffiffiffiffiffiffiffi  3kT 3kT 1=2 V ¼ ¼ ; ðA-21Þ thermal m m where the Boltzmann constant k = 1.38065 9 10-23 JK-1.

Gas pressure, PG, of particles of number density, N, and temperature T:

PG ¼ NkT; ðA-22Þ where the Boltzmann constant k = 1.38065 9 10-23 JK-1.

Radiation pressure, Pr, for a temperature T: aT4 P ¼ ðA-23Þ r 3 where the radiation constant a = 7.5657 9 10-16 Jm-3 K-4.

Magnetic pressure, PB, of a magnetic field of strength, B: B2 PB ¼ ; ðA-24Þ 2l0 -6 -2 where the magnetic constant l0 = 1.2566 9 10 NA . Energy radiated, DE, by a mass loss, Dm, during nuclear reactions:

DE ¼ Dmc2; ðA-25Þ where the speed of light c = 2.9979 9 108 ms-1.

Schwarzschild radius, Rsch, of a mass, M, of radius R: 2GM 3 M Rsch ¼ 2 ¼ 2:95 10 m; ðA-26Þ c M where the universal gravitational constant G = 6.674 9 10-11 m3 kg-1 s-2 and 30 the Sun’s mass M = 1.989 9 10 kg.

Hubble law for the recession velocity Vr of a at a distance D:

Vr ¼ H0 D; ðA-27Þ

-1 -1 where the Hubble constant H0 = 75 km s Mpc and 1 Mpc = 3.08568 9 1022 m. Author Index

A Bondi, Hermann, 514 Abell, George, 7, 500 Bort, Leon Philippe Teisserenc de, 146 Adams, Walter S., 321, 418 Bowen, Ira S., 358, 414 Alfvén, Hannes, 157, 267 Boyle, Robert, 141 Alpher, Ralph A., 353, 526 Bradley, James, 13, 14, 37 Ambartsumian, Viktor, 115 Brahe, Tycho, 69, 433, 444 Anderson, Carl, 205, 208 Braun, Karl F., 146 Anderson, Wilhelm, 427, 428 Bruno, Giordano, 400 Ångström, Anders Jonas, 161 Bunsen, Robert, 160 Appleton, E., 147 Burbidge, E. Margaret, 351 Aristotle, 2 Burbidge, Geoffrey R., 351 Arrhenius, Svante, 59 Aston, Francis, 220 Atkinson, Robert d’Escourt, 222, 349 C Axford, William I., 274 Cannon, Annie Jump, 305 Carrington, Richard Christopher, 122, 127 Cassini, Giovanni Domenico, 36, 52 B Cavendish, Henry, 75 Baade, Walter, 203, 434, 446, Chadwick, James, 450 448–450, 515 Chandrasekhar, Subrahmanyan, 25, 325, 428 Babcock, Horace, W., 260 Cherenkov, Pavel A., 241 Bahcall, John N., 238 Chwolson, Orest, 504 Balmer, Johann, 166 Clairault, Alexis Claude de, 80 Barnard, Edward E., 109, 366 Clapeyron, Émile, 143 Barrett, Alan, 379 Clark, Alvan, 418 Becquerel, Henri, 192 Clausius, Rudolf, 134, 143 Bell, Jocelyn, 453 Clay, Jacob, 203 Bennett, Charles L. ‘‘Chuck’’, 530 Cockcroft, John, 208, 211 Bessel, Friedrich Wilhelm, 294, 295, 418 Colombo, Giuseppe, 118 Bethe, Hans A, 213, 231, 233, Compton, Arthur H., 25, 64, 203 335, 353 Condon, Edward U., 197 Bevis, John, 445 Coulomb, Charles Augustin de, 169 Biermann, Ludwig, 269 Cowan, Clyde L., 201 Blaauw, Adriaan, 115 Critchfield, Charles, 231 Blackett, Patrick, 208, 209 Curie, Manya (Marie), 193 Bohr, Niels, 168, 200 Curie, Pierre, 193 Boltzmann, Ludwig, 50, 132, 174, 309 Curtis, Heber D., 487

K. R. Lang, Essential Astrophysics, Undergraduate Lecture Notes in Physics, 615 DOI: 10.1007/978-3-642-35963-7, Ó Springer-Verlag Berlin Heidelberg 2013 616 Author Index

D H Davis, Raymond Jr., 239, 460 Hahn, Otto, 212 Democritus, 125 Hale, George Ellery, 189, 258 Dirac, Paul Adrien Maurice, 206 Hall, John Scoville, 368 Doppler, Christiaan, 107, 108, 180 Halley, Edmond, 74, 106 Dreyer, J. L. E., 7 Harkins, Willam D., 350 Duncan, John C., 445 Härm, Richard, 346 Dungey, James, 288 Hayashi, Chushiro, 353, 396, 533 Hazard, Cyril, 548 Heaviside, Oliver, 147, 371 E Heisenberg, Werner, 213, 424 Eddington, Arthur Stanley, 111, 216, 220, 310, Helmholtz, Hermann von, 132, 215 312, 326, 349, 413, 421, 462, 463, 475, Henderson, Thomas, 295 504, 514, 517, 557 Herman, Robert C., 526 Edlén, Bengt, 256 Herschel, Caroline, 26 Einstein, Albert, 41, 42, 60, 93, 213, 220, 504, Herschel, John, 7 514, 517 Herschel, William, 7, 26, 39, 249, 412, 471 Epicurus of Samos, 440 Hertz, Heinrich, 40 Ewen, Harold I. ‘‘Doc’’, 376 Hertzsprung, Ejnar, 318, 319 Hess, Victor Franz, 202, 208 Hewish, Antony, 453 F Hiltner, William A., 368 Faraday, Michael, 33, 126 Hipparchus, 11, 13, 296 Fermi, Enrico, 200, 213, 425 Hodgson, Richard, 277 Feynman, Richard, 213 Houtermans, Fritz, 222 Follin, James W., 526 Hoyle, Fred, 278, 343, 346, 351, 437, 514 Forbush, Scott, 203, 273 Hubble, Edwin, 25, 445, 487, 494, 517 Fourier, Jean-Baptiste, 58 Huggins, William, 180, 257, 412 Fowler, Ralph A., 178 Hulse, Russell A., 96, 459 Fowler, Ralph H., 425 Humason, Milton, 495 Fowler, William A. ‘‘Willy’’, 225, 338, 352, 429, 437 Fraunhofer, Joseph von, 159, 163 J Friedmann, Aleksandr, 519 Jansky, Karl, 369 Janssen, Pierre Jules César, 163 Jeans, James, 46, 140, 389 G Jeffreys, Harold, 86 Galilei, Galileo, 22, 73, 99, 471 Joule, James Prescott, 54, 131 Gamow, George, 196, 222, 353, 441, Joy, Alfred H., 431 526, 532 Gauss, Carl Friedrich, 78 Ghez, Andrea, 485 K Giacconi, Riccardo, 460 Kant, Immanuel, 381, 479 Gilbert, William, 283 Kapteyn, Jacobus C., 110, 472 Gill, David, 52 Keeling, Charles D., 59 Giovanelli, Ronald G., 267 Keenan, Philip C., 322 Gold, Thomas, 278, 284, 290, 454, 514 Kelvin, Lord (William Thomson), 28, 215 Goodricke, John, 474 Kennedy, Roy J., 42 Gore, Albert Arnold (Al), 59 Kennelly, Arthur E., 147 Greenstein, Jesse, 548 Kepler, Johannes, 69, 70, 72, 269, 433 Gribov, Aladimir, 243 Kerr, Frank, 376 Grotrian, Walter, 256 Kerr, Roy, 470 Gurney, Ronald W., 197 Kirchhoff, Gustav., 65, 160 Author Index 617

Klebesadel, Ray W., 552 Morrison, Philip, 213 Kohlschütter, Arnold, 321 Mulders, Gerard F. W., 185 Koshiba, Masatoshi, 240, 241, 460 Murdin, Paul, 467 Kraft, Robert P., 431 Kronig, August, 143 Kruskal, Martin, 470 N Neugebauer, Marcia, 269 Neumann, John von, 346 L Newcomb, Simon, 13, 78 Lampland, Carl, 450 Newton, Isaac, 20, 37, 73, 81, 99 Landau, Lev, 451 Lane, Jonathan Homer, 218 Laplace, Pierre-Simon, 154, 382, 465 O Lawrence, Ernest, 208, 211 Olbers, Heinrich Wilhelm, 493 Leavitt, Henrietta Swan, 474 Olson, Roy A., 552 Leighton, Robert B., 250 Oort, Jan, 480 Lemaître, Georges, 517, 541, 556, 557, 560 Öpik, Ernst, 340, 394, 489 Leucippus, 125 Oppenheimer, J. Robert, 213, 451 LeVerrier, Urbain Jean Joseph, 93 Osterbrock, Donald E., 267 Lewis, John S., 139 Lifshitz, Evgeny, 541 Lockyer, Joseph Norman, 163, 176 P Lorentz, Hendrik, A., 40, 187 Pacini, Franco, 450 Lowell, Percival, 492 Parker, Eugene, 269, 273 Lucretius, 73, 125, 400 Parsons, William (Earl of Rosse), 445 Pauli, Wolfgang, 200, 425 Pawsey, Joseph L., 546 M Payne, Cecilia H., 179 Maclaurin, Colin, 120 Pease, F. G., 307, 489 Magellan, Ferdinand, 474 Penrose, Roger, 470 Marconi, Guglielmo, 146 Penzias, Arno, 526, 528 Mather, John C., 527 Perlmutter, Saul, 553, 554 Maxwell, James Clerk, 33, 135 Perrin, Jean, 191 Mayall, Nicholas, 495 Pickering, Edward C., 305 Mayer, Jules Robert, 131 Piddington, Jack H., 267 Mayor, Michel, 405 Pigott, Edward, 474 McCrea, William H., 179 Planck, Max, 44, 45 Meitner, Lise, 212 Pogson, Norman, 296 Menzel, Donald, 413 Pontecorvo, Bruno, 243 Messier, Charles, 6, 357, 445 Purcell, Edward M., 376 Meyer, Peter, 273 Pythagoras, 2 Michell, John, 465 Michelson, Albert A., 41, 307 Mie, Gustav, 62 Q Mikheyev, Stanislav P., 243 Queloz, Didier, 405 Millikan, Robert A., 60, 126, 202 Milne, Edward, 178 Minkowski, Hermann, 43 R Minkowski, Rudolph, 435 Ramsay, William, 164 Minnaert, Marcel, 185 Rayleigh, Lord (John Strutt), 46, 61, 62 Morgan, William W., 322 Reber, Grote, 369 Morley, Edward W., 41 Reines, Frederick, 201, 208 618 Author Index

Richer, Jean, 52 T Riess, Adam G., 555 Taylor, G. I., 86 Roche, Édouard A., 90, 432 Taylor, Joseph H. Jr., 96, 459 Roll, Peter G., 528 Thomson, Joseph John, 63, 126, 191 Rømer, Ole, 36 Totsuka, Yoji, 241 Röntgen, Wilhelm, 38, 191 Townes, Charles H., 379 Roosevelt, Franklin, 213 Trumpler, Robert J., 367 Russell, Henry Norris, 179, 318, 319, 334 Turck-Chièze, Sylvaine, 239 Rutherford, Ernest, 127, 193, 220, 514 Tyndall, John, 58, 61, 309 Rydberg, Johannes, 167 Ryle, Martin, 546 U Unsöld, Albrecht, 179 S Urey, Harold Clayton, 350 Saha, Meghnad, 177 Salpeter, Edwin E., 317, 341, 544, 550 V Sandage, Allan, 346, 495 Van de Hulst, Hendrik C. ‘‘Henk’’, 375 Schiaparelli, Giovanni, 116 Vogt, Heinrich, 334 Schmidt, Brian P., 555 Volkoff, George M., 451 Schmidt, Maarten, 548 Schönberg, Mario, 325, 441 Schramm, David, 353, 534 W Schwabe, Samuel Heinrich, 258 Wagoner, Robert V., 353 Schwarzschild, Karl, 346, 467 Walker, Merle F., 430 Schwarzschild, Martin, 346 Walton, Ernest T.S., 208, 211 Seyfert, Carl K., 545 Webster, B. Louise, 467 Shajn, Grigory Ambramovich, 124 Weizsäcker, Carl Friedrich von, 213, 231, Shapley, Harlow, 476, 487, 517 336, 350 Shatzman, Evry, 419 Wien, Wilhelm, 46 Shelton, Ian, 439 Wild, J. Paul, 277 Shklovskii, Iosif S., 376 Wildt, Rupert, 249 Simpson, John, 273 Wilkinson, David T., 528, 530 Slipher, Vesto, 497–494, 517 Wilson, Charles Thomas Rees, 205, 208 Smirnov, Alexei Y., 243 Wilson, Robert, 526, 528 Smoot, George, 529 Wolf, Maximillian, 366 Snyder, Conway W., 269 Wolfenstein, Lincoln, 243 Soddy, Frederick, 194 Wollaston, William Hyde, 159 Soldner, Johann George von, 94 Spitzer, Lyman Jr., 26 Stefan, Joseph, 50, 309 Y Stoner, Edmund C., 428 Yukawa, Hideki, 208 Stoney, George Johnstone, 126, 138 Størmer, Carl, 187 Strömgren, Bengt, 179, 232, 364 Z Strong, Ian B., 552 Zanstra, Herman, 413 Struve, Otto, 124 Zeeman, Pieter, 187 Suess, Hans E., 59, 350 Zeldovich, Yakov B., 550 Swope, Henrietta H., 515 Zhevakin, Sergi A., 475 Szekeres, George, 470 Zwicky, Fritz, 203, 434, 450, 502 Subject Index

A Alpha Magnetic Spectrometer, 209 Aberration, 14, 15, 37 Alpha particles, 193, 194 Absolute magnitude, 300 Alpha rays, 193 Absolute visual magnitude, 300 Ammonia, interstellar, 379 Absolute zero, 130 Andromeda , 488 Absorption coefficient, 65 collision with , 508 Absorption lines, 159, 160 distance, 488, 489 Absorption, starlight, 367–369 Ångström, 35 Abundant elements, Sun, 164, 165, 352 Angular momentum, 87 Acceleration, 74, 544 Earth, 88 expansion of universe, 553 Jupiter, 385 gravity, 79 Moon, 88 Accretion disk, 461 Sun, 385 Accretion luminosity, 463, 464 Angular resolution, 21, 22 Accretion rate, 464 An Inconvenient Truth, 59 Active galactic nuclei, 545–549 Annual parallax, 293, 294 emission lines, 549 Annual , 107 super-massive black holes, 549 Antares, 327 Active region, 262 Antennae , 509 Age Anti-gravity, 555 Crab Nebula, 447 Aphelion, 71 Earth, 198 Apparent magnitude, 296 expanding universe, 532, 540 Apparent radiation flux, 299 globular star clusters, 345, 346 Apparent visual magnitude, 297, 298 meteorites, 198 Arcturus, 327 Moon, 198 radius, 307 observable universe, 513–516, 532, 540 Asteroid belt, 384 open star clusters, 345, 347 Astronomical unit (AU), 28, 50, 70 planetary nebulae, 415 radar value, 53 radio pulsar, 456 Astronomy, 1 Sun, 196, 217 Astrophysics, 1 Albedo, 57 Asymptotic branch, Hertzsprung–Russell Aldebaran, 327 diagram, 347, 348 Alfvén velocity, 157 Atmospheres, 138 Alfvén waves, 157 circulation, 145 coronal heating, 267 speed of sound, 155 interplanetary medium, 157, 158 thermal evaporation, 140 Alpha Centauri, 315 thermal velocity, 133, 134 Alpha decay, 194, 195 Atom, 125

K. R. Lang, Essential Astrophysics, Undergraduate Lecture Notes in Physics, 619 DOI: 10.1007/978-3-642-35963-7, Ó Springer-Verlag Berlin Heidelberg 2013 620 Subject Index

Atom (cont.) Big Dipper, 11 Bohr, 168 Binary pulsar, 96, 459, 460 excited, 173 Binary , 314, 315 formation, 535 eclipsing, 314, 315 ground state, 173 mass, 314 nucleus, 127 orbital motion, 96, 97 physical properties, 129 spectroscopic, 315 quantization, 167 visual, 315, 316 radius, 128 Binding energy, 78, 226, 227 Atomic bomb, 213 gravitational, 78 Atomic mass number, 130 nucleus, 226, 227 Atomic mass unit, 128, 226 Binding energy per nucleon, 226 Atomic nucleus, 127 Black holes, 465–470, 484, 550 physical properties, 129 collapse time, 469 radius, 128 description, 467 Atomic number, 130 event horizon, 470 , 484, 485 imagining, 465 B Milky Way, 484, 485 Background radiation, 526–546 observation, 466, 467 angular power spectrum, 530, 531 Schwarzschild radius, 468 anisotropy, 529, 531 singularity, 470 blackbody spectrum, 527, 528 super-massive, 484, 485, 550, 551 discovery, 526 X-rays, 469, 470 isotropy, 529 Blackbody, 44 photon density, 528, 529, 531 Blackbody radiation, 44 temperature, 527, 531 brightness distribution, 45 temperature fluctuations, 530, 531 energy density, 47 Balmer limit, 172 radiant flux, 48, 50 Balmer lines, 166 Blackbody spectrum, 45 , 167, 171 background radiation, 527, 528 Balmer transition, 171 Blue sky, 61 Bar, 141 Bohr atom, 167 Barnard’s star, velocity, 109–112 Bohr magneton, 188 Barn unit, 226 Bolometric magnitude, 303 Barometric equation, 144 Boltzmann constant, 30 Barometric law, 144 Boltzmann distribution, 174, 176 Baryonic matter, 531 Bond albedo, 57 Beta decay, 199, 200 Bound-bound transition probability, 175 Beta Pictoris, planet-forming disk, 401, 403 Bow shock, 284, 285 Beta rays, 193, 198, 203 Bow shock distance, 286 Betelgeuse, 327 Earth, 286 angular diameter, 307 Jupiter, 286 mass loss, 309 Braking radiation, 362, 363 radius, 308 Bremsstrahlung, 362, 363 winds, 309 Bright named planetary nebulae, 417 , 522–525 Brightest stars, 296, 297 neutron–proton ratio, 534 Brightness, 296 nucleosynthesis, 352–354, 534, 535 cloud, 65, 66 pair annihilation, 524 Brightness distribution, 45 radiation temperature, 526 blackbody radiation, 45 singularity, 523 thermal, 45 Big-bang nucleosynthesis, 352–354, Brown dwarf star, 312 534, 535 Butterfly diagram, 259 Subject Index 621

C Composition, Sun, 160, 161 Calorific rays, 40 Compton Gamma Ray Observatory Carbon burning, 349 (CGRO) , 25 Carbon monoxide, interstellar, 379 Compton scattering, 64 Cassiopiea A supernova remnant, 444 Conservation of angular momentum, 70, 71, Cat’s Eye Nebula, 412 385 Cataclysmic variable star, 431 Earth-Moon, 87 Celestial coordinates, 5 Conservation of energy, 76, 131, 200 Celestial equator, 4 Constant of aberration, 14 Celestial positions, standard epoch, 13 Constant of nutation, 14 Celestial sphere, 4 Continuum spectrum, 44 X-3, 460, 461 Convection, 245, 248, 339, 340 Centrifugal acceleration, 119 Convective zones, stars, 340 Centrifugal force, 118 Corona, 255 Cepheid variable stars, 473–476 eclipse, 256 period-luminosity relation, 475 forbidden emission lines in visible light, nearby galaxies, 497 257 spiral nebulae, 487, 488 radio radiation, 256 Chandrasekhar limit, 429 temperature, 256 Charge-coupled device, 21 ultraviolet and X-ray emission lines, 258 Chandra X-ray Observatory (CXO) , 25, 444, X-ray radiation, 257, 276 445, 450, 509 Coronal heating, 265–267 Chemical elements, 125 Alfvén waves, 267 origin, 347–354 magnetic reconnection, 267 Chemical ingredients, Sun, 160, 163 Coronal holes, 268 Chromosphere, 255 11-year magnetic activity cycle, 268 heating by sound waves, 266 origin of high-speed solar wind, 261 Chromospheric evaporation, 280 Coronal loops, 261–264 Civil time, 15 11-year magnetic activity cycle, 265 Clairault’s theorem, 80 magnetic and gas pressure, 264, 265 Closed universe, 520 Coronal mass ejections, 281 Cloud, brightness, 65, 66 energy, 282 Cloud chamber, 205 physical properties, 283 Clusters of galaxies, 500–507 travel time to Earth, 283 dark matter, 502–505 Coronium, 256 gravitational lens, 505, 506 COsmic Background Explorer (COBE), intergalactic matter, 503 527–530 physical properties, 502 Cosmic microwave background radiation. See X-ray radiation, 504 Background radiation 21 cm spin transition of , 375–378 Cosmic ray shower, 207 CNO cycle, 335–339 Cosmic rays, 202–209 Cold dark matter, 542 acceleration in supernovae, 203 Collisions, 134, 134 discovery, 199 galaxies, 508, 509 energy, 203 particles, 134, 135 flux, 204 Color index, 304 inverse correlation with solar activity, 203 Colors, 37, 304 protons, 203 stars, 303 Cosmic static, 370 wavelength, 37 Cosmic web, 511 Coma cluster of galaxies, dark matter, 503 Cosmological constant, 554–559 Communication disruption, 290 Cosmological principle, 529 622 Subject Index

Coulomb’s law, 221 relativistic, 426 Crab Nebula, 446–450 Degenerate electron pressure, 426 age, 447, 449 Degenerate neutron pressure, 465 amorphous region, 446, 448 Delta Cephei, 474, 476 emission lines, 446 distance, 476 nonthermal radiation, 446 Density parameter, 519, 558 physical properties, 447 Density waves, 483 polarized light, 448 De Rerum Natura, 119 progenitor star, 447 , 120, 480, 481 radio pulsar, 447, 448, 450, 459 Milky Way, 479–482 synchrotron radiation, 447–449 Sun, 120 X-rays, 447–449 Differentiation, 384 Crab Nebula supernova remnant, 446–448. Discovery See Crab Nebula background radiation, 526 Critical mass density, to stop expanding uni- cosmic rays, 202 verse, 500, 516, 520 dark energy, 554–555 Cross section, tunneling, 229 exoplanets, 403–408 Curvature, space, 94, 95 expanding universe, 493–494 Curve of growth, 185 galaxies, 487–492 Cyclotron, 211 gamma-ray bursts, 552 61 Cygni, distance, 295 helium, 163 A, 546, 547 infrared radiation, 39 Cygnus X-1, 467 interstellar hydrogen 21 cm line, 375–378 ionosphere, 146 D muon, 207 Dark energy, 554–559 pion, 208 constraints, 559 positron, 206 cosmological constant, 555–559 pulsars, 452, 453 discovery, 554, 555 , 549 Dark halo, 486 radioactivity, 193, 194 Dark matter, 531–535 radio waves, 40 clusters of galaxies, 500–504 solar wind, 268 Coma cluster of galaxies, 503 tau lepton, 211 constraints, 559 white dwarf stars, 418, 419 galaxies, 490 X-ray pulsars, 460, 461 galaxy formation, 542 X-rays, 191, 192 Milky Way, 485, 486 Displacement law, 46 spiral galaxies, 488, 491 Distance star formation, 543 Andromeda Nebula, 488–490 Day, 30 galactic center, 476, 477 lengthening, 80, 81 galaxies, 496 sidereal, 17 Proxima Centauri, 53 solar, 15, 18 spiral nebulae, 487–489 Deceleration parameter, 519, 558 Sun, 50, 52 Declination, 5 Distance modulus, 302 Decoupling time, 539 , 107, 108, 180 Deflection of starlight, 94 Doppler line broadening, 188 Degeneracy pressure, 425 Dust, 367–368 Degenerate, 425 Dwarf novae, 430 Degenerate electron gas, 423–427 Dwarf nova SS Cygni, 430, 431 Subject Index 623

E Seyfert galaxies, 546 Earth Emission nebulae, 357–365 age, 198, 216 bright named, 359 atmospheric pressure, 141, 142, 145 physical properties, 361 equatorial radius, 12 spectral lines, 358, 360 escape speed, 100, 102 Energy flattening factor, 12, 79 conservation, 76, 131, 200 gravitational redshift, 181, 182 kinetic, 130, 132 gravity, 79 light, 59 internal heat from radioactivity, 216 nuclear reaction, 223 local acceleration of gravity, 79 photon, 59 magnetic storms, 288 supernova, 442 magnetosphere, 283–285 thermal, 132 mass, 75, 80 Energy density, blackbody radiation, 48 mass density, 75 Energy distribution function, 137 mean radius, 11 Energy generation, nuclear reaction, 231 orbital properties, 78 Energy release, nuclear fusion, 226 physical properties, 77 Equation of energy conservation, 333 rotation, 3 Equation of hydrostatic equilibrium, 332 surface gravitational acceleration, 80 Equation of mass conservation, 333 Eccentricity, 72 Equation of radiative energy transfer, 333 Eclipsing binary stars, 314, 315 Equinox, 8 Ecliptic, 4 40 Eridani B, 327, 418 Eddington limit, 462, 463 Escape speed, 99, 100 Eddington luminosity, 312, 313 Earth, 100, 102 Effective temperature, 55 Moon, 100, 102 planets, 56, 57 Sun, 100, 102 Sun, 55 Escape velocity, 77 Effective thermal energy, 230 Earth, 100, 102 Einstein ring, 506, 507 Milky Way, 492 Einstein-De Sitter universe, 520 Moon, 100, 101 Electric constant, 31 neutron star, 451 Electromagnetic fields, 33 planet, 139 Electromagnetic radiation, 33 star cluster, 111 Electromagnetic spectrum, 37, 39 Sun, 100, 101 Electromagnetic waves, 33 Eskimo Nebula, 416 Electron, 126, 129 Ether, 41 mass, 191 Event horizon, 470 physical properties, 129 Ever-expanding universe, 521 quantized orbit, 168 Exclusion principle, 424 Electron , 64 Exobase, 140 Electron degenerate pressure, 425 Exoplanets, 403–410 Electron neutrinos, 242 atmospheres, 410 Electron volt, 150 discovery, 405 Electron-positron annihilation, 206 flat multi-planet systems, 408 Elementary charge, 126 habitable, 409 Ellipse, 72 hot-Jupiters, 408 , 491 mass, 405, 406 Emission lines, 159, 160 orbital distance, 406 corona, 256 Exosphere, 147 Crab Nebula, 446 Expanding universe, 493–495 planetary nebulae, 413, 414 accelerated expansion, 555, 556 quasars, 549 age, 513–516, 532, 540 radio galaxies, 546 cosmological constant, 555–559 624 Subject Index

Expanding universe (cont.) Free fall time, 397 critical mass density, 500, 516, 520 Free-free radiation, 362, 363 decoupling time, 539, 540 Frequency discovery, 491–493 , 152 fate, 555 radiation, 35, 36 General Theory of Relativity, 517 Friedmann equations, 519 history, 537–540 mass density, 537 matter era, 527 G origin, 513 Galactic center, 476–484 radiation energy density, 536, 537 distance, 476–478 radiation era, 527 super-massive black hole, 484, 485 radiation temperature, 538, 539 Galaxies, 487–510 rate of expansion, 514 active nuclei, 544–549 recombination time, 539, 540 center, 499 reionization time, 540 clusters, 500–504 size, 518 collision, 508 Expansion age, universe, 514–518 cosmic web, 511 Expansion line broadening, 184 dark matter, 490, 491 Expansion, stellar associations, 115 discovery, 487–491 Expansion velocity, 185 distance, 494, 496 Extragalactic nebulae, 490 edge, 499 first, 540–544 formation, 543–544 F giant elliptical, 550, 551 Faint-Young-Sun paradox, 252, 253 gravitational lens, 504, 506 Fate, 254, 257 look-back time, 512 expanding universe, 560 luminosity, 492–498 stars, 411 luminosity function, 497 Sun, 252, 255 motion, 492, 508, 510 Fermi Lab, 212 number density, 492, 498 Fermi unit, 128 peculiar motions, 508 First generation stars, 354 physical properties, 492 Five-minute oscillations, Sun, 251 redshift, 494 Flat universe, 517, 520 starburst, 543 Flattening factor, Earth, 11, 12, 79 streams, 508 Focal length, 19 super-massive black holes, 484, 485, Fomalhaut, planet-forming disk, 401, 402 547–551 Forbidden emission lines, corona, 257 voids, 510 Forbush effect, 203 walls, 510 Force, 74, 127 Galaxy, 471–488 gravitational, 74 Gamma-ray bursts, 552 nuclear, 127 afterglow, 552 Formation discovery, 552 atoms, 535 luminosity, 553 galaxies, 540–544 supernovae, 554 giant star, 341 Gamma rays, 39, 38 planetary nebulae, 415 Gamow energy, 229 red giant star, 341 Gas pressure, 141, 142, 264, 330 solar system, 381–387 Gaussian constant of gravitation, 78 stars, 381–399, 540–544 General Catalogue, 7 Fourth state of matter, 149, 151 General Theory of Relativity, 94, 468, 517 Fraunhofer absorption lines, 159, 161–163 Geocentric gravitational constant, 75 Free-bound radiation, 361, 362 Geomagnetic storms, 288 Subject Index 625

Geosynchronous orbit, 103 Ground state, 173 Giant elliptical galaxies, super-massive black Gyration radius, 371 holes, 542, 546 Gyrofrequency, 371 Giant molecular clouds, 385–391 free fall time, 397 gravitational collapse, 391 H physical properties, 388 H I regions, 375, 377 Giant planets, 383 equilibrium, 392, 393 Giant stars, 306, 321 physical properties, 378 formation, 336 H II regions, 357, 361 pulsation, 327 equilibrium, 392 Global Positioning System, 3, 12, 16 physical properties, 361 Global warming, 58, 59 Habitable zone, 57, 409 Globular star clusters, 111, 114, 343–345, Hale Telescope, 21 475–478 Heat, 130 age, 345, 346 Heliopause, 276 Cepheid variables, 474 Helioseismology, 123, 251 distribution, 477 Heliosheath, 276 Hertzsprung–Russell diagrams , 347 Heliosphere, 275 spheroid, 478 Helium atom, 129 stellar motions, 116 Helium burning, 340–343 Gran Telescopio Canarias, 21 temperature, 342 Granulation, 249, 250 Helium, 129, 165, 534 Gravitation, 74 big-bang nucleosynthesis, 534 Gravitational binding energy, 78 discovery in Sun, 164 Gravitational collapse, 389–395 physical properties, 129 Kelvin–Helmholtz time, 216 Herschel Telescope, 25 triggering, 392 Hertzsprung–Russell diagram, 318–320 Gravitational constant, 30, 75 protostars, 396 Gaussian, 78 star clusters, 343–347 geocentric, 75 Higgs boson, 212 universal, 30, 75 Hinode, 25 Gravitational force, 74 HIPPARCOS, 8, 25 Gravitational lens, 505, 506 Hertzsprung–Russell diagram, 319, 320 clusters of galaxies, 503 Oort’s constants, 480 galaxies, 504, 505 star density, 478 Gravitational potential energy, 78 star distances, 295 Gravitational radiation, 97 stellar proper motions, 111 Gravitational radius, 468 Historical supernovae, 434 Gravitational redshift, 181, 182 Homestake neutrino detector, 240 Sun, 181 Hooker Telescope, 21 white dwarf stars, 421 Horizontal branch, Hertzsprung–Russell dia- Gravitational waves, 97 gram, 347 Gravity, 73 Hot-Jupiters, 408 acceleration, 79 H-R diagram. See Hertzsprung–Russell cause, 93 diagram Earth, 80 Hubble constant, 493–497 local acceleration, 73 Hubble expansion parameter, 519, 558 Great Attractor, 508 Hubble law, 493–499 Great Observatories, 25 Hubble Space Telescope (HST), 25, 402, 476, Great Wall, 510 496, 497, 501, 505, 509, 516 Greenhouse effect, 58, 59 Hubble time, 512 Greenwich sidereal time, 18 Hydrogen, 126 626 Subject Index

Hydrogen (cont.) J Balmer lines, 166 James Webb Space Telescope (JWST), 26 big-bang nucleosynthesis, 534 Jeans density, 391 interstellar, 375–377 Jeans length, 389 most abundant element in most stars, 179 Jeans mass, 389, 390 physical properties, 129 Jeans radius, 391 Hydrogen alpha line, 167 Joule, 54 Hydrogen burning, 231–239, 335–340 Julian century, 15 Hydrostatic equilibrium, 330 Julian Date, 13 Julian year, 15

I law, 142 K Index Catalogue, 7 Kamiokande neutrino detector, 240 Inflation, 523 Kapteyn Universe, 477 InfraRed Astronomical Satellite (IRAS), 401 Kapteyn’s star, velocity, 110, 111 Infrared radiation, 39 Keck Telescopes, 21 discovery, 60 Kelvin-Helmholtz time, 216 Initial mass function, stars, 317 Kepler mission, 409 Instability strip, Hertzsprung–Russell diagram, Kepler’s first law of planetary motion, 69, 70 347 Kepler’s harmonic relationship, 71, 73 Interferometer, 23, 24, 306 Kepler’s second law of planetary Interferometry, 23 motion, 69, 70 stars, 307 Kepler’s third law, Newtonian expression, 103 International Atomic Time, 15 Kepler’s third law of planetary motion, 71, 72 International celestial reference system, 6 Kiloparsec (kpc), 29 Interplanetary magnetic spiral, 289 Kinetic energy, 100, 130, 132 Interstellar Boundary EXplorer (IBEX) , 276 Kinetic temperature, 133 Interstellar dust, 367, 368 Kirchhoff’s law, 65 reddens starlight, 304 Interstellar hydrogen atoms, 375–378 Interstellar molecular hydrogen, 380 L Interstellar molecules, 378, 379 Large Binocular Telescope, 21 radio radiation, 379 Large Hadron Collider, 212 Interstellar water, 379 Large stars, 306 Inverse beta decay, 207 Latitude, 23 Inverse Compton effect, 64 Leptons, 242 Inverse square law, 74, 299 Lifetime gravity, 74 main sequence, 323–326 light, 299 nuclear fusion in Sun, 219 Io, eclipse period, 36 nuclear reaction, 219 Ion, 149 protostars, 395–397 Ionization potential, 149 radioactive atom, 196–199 abundant atoms, 178 synchrotron radiation, 374 Ionization wavelength, hydrogen and oxygen, Light bending, 95, 96 358 Light travel time, 294 Ionosphere, 145, 146 astronomical unit (AU), 28, 52 discovery, 147 Light-year, 29, 294 origin , 152 Line broadening plasma frequency, 152 expansion, 184 temperature, 151 rotation, 184 Isotopes, 130 thermal motion, 183 Subject Index 627

Zeeman effect, 183, 187–190 Magnetotail, 285 Line splitting, Zeeman effect, 183, 187–190 Main sequence, 318, 320 Local hour angle, 19 lifetime, 323–325 Local sidereal time, 17 stellar mass, 323 Longitude, 2, 3 zero age, 332 Look-back time, galaxies, 512 Main-sequence stars, 320, 321, 323, 324 Lorentz contraction, 43 physical properties, 322 Lorentz factor, 41 Mariner 2, 270 Lorentz transformation, 41 Mariner 5, 157 Luminiferous ether, 41 Mars, parallax, 52 Luminosity, 298 Mass, 74 accretion, 463, 464 binary stars, 314 Eddington, 463 dark halo Milky Way, 486 galaxies, 491, 498 dark matter Milky Way, 487 gamma-ray bursts, 552 Earth, 75, 81 Milky Way, 471–486 emission nebula, 365 radio pulsar, 456, 457 H II region, 365 stars, 299 increase with motion, 42 Sun, 27, 54, 298–300 Milky Way, 479, 482 synchrotron radiation, 374 spectroscopic binary stars, 316–318 Luminosity class, stars, 321, 323 stars, 306 Luminosity function, galaxies, 497 Sun, 26, 80 Lunik 2, 269 super-massive black hole galactic center, Lunisolar precession, 13 485 Lyman transition, 171 super-massive black holes, 484 , 168, 171 upper limit for stars, 313 Mass defect, nucleus, 226 Mass distribution, stars, 544 M Mass-energy equivalence, 220 Magnetic brakes, Sun rotation, 386, 387 Mass loss Magnetic cloud, from Sun, 291 Betelgeuse, 309 Magnetic constant, 31 nuclear fusion in Sun, 236 Magnetic energy, 393 red giant stars, 328 Magnetic fields solar wind, 273 cosmic, 189 supergiant stars, 309, 348 Earth, 189 VY Canis Majoris, 309 energy density, 157 VY Cephei A, 309 interstellar, 188 Mass-luminosity relation, stars, 310, 311 neutron stars, 456 Matter era, expanding universe, 536 radio pulsars, 457, 458 Maxwell’s equations, 33, 34 solar wind, 190 Maxwell speed distribution, 135, 136 Sun, 258, 289 Mean collision time, 135 sunspots, 188 Mean free path, 134, 135 white dwarf star, 423, 455 Mean speed, 137 Zeeman effect, 183, 186–188 Megaparsec (Mpc), 29 Magnetic pressure, 141, 264 M 87, super-massive black hole, 550 Magnetic reconnection Mercury, 93, 94, 116, 117 coronal heating, 267 precession of perihelion, 93, 94 entry to magnetosphere, 288 rotation, 116, 117 solar flares, 278, 279 Mesosphere, 146 Magnetic waves, 156, 158, 267 Meteorites, age, 198 Magnetic white dwarf stars, 423 Metric, 43 Magnetosphere, 283–285 MeV unit, 226 planets, 285, 286 Michelson–Morley experiment, 41 628 Subject Index

Micron, 35 Negative beta decay, 201 Microwaves, 37, 39 Negative hydrogen ion, solar photosphere, 249 Mie scattering, 62 Neutrinos, 200, 237 Milky Way, 471–486 electron, 240, 241 central super-massive black hole, 484 muon, 240, 241 collision with Andromeda Nebula, 508 observation, 205 dark halo, 486 oscillation, 240, 241 dark matter, 486, 487 Sun, 241–243 differential rotation, 479, 480 supernova, 441 escape velocity, 493 tau, 240 luminosity, 478, 482 types, 242 mass, 478, 482 Neutron, 125 physical properties, 478 physical properties, 129 radio emission, 369–375 Neutron capture, 352 shape, 471, 472 Neutron stars, 450–463 size, 471, 472 degenerate neutron pressure, 452 spiral arms, 482, 483 escape velocity, 451 super-massive black hole, 484, 485 magnetic field strength, 455 synchrotron radiation, 374, 375 physical properties, 451 Milne universe, 521 radius, 451 Molecules, 126 rotation period, 451, 454 interstellar, 378, 379 superfluid and superconducting, 452 planetary atmospheres, 138, 139 New General Catalogue, 7 Moon Newtonian focus, 20 age, 198 Newton’s first law of motion, 99 escape speed, 100, 101 Nonthermal radiation, 370, 373 ocean tides, 81 Crab Nebula, 446–449 orbital properties, 82 Nonthermal velocities, 370 orbital speed, 103 North celestial pole, 6 outward motion, 87 North Star, 10 physical properties, 82 Nova Aquilae 1918, 429 Morgan–Keenan (M–K) luminosity classes, Nova Cygni 1992, 429 321 Novae, 429–432 Most probable speed , 136 origin, 429–432 Motion, 99 physical properties, 430 galaxies, 492–499, 508, 509 thermonuclear explosion white dwarf star, kinetic energy, 99, 130 430, 431 orbital, 101 Nova Herculis 1934, 429 ordered, 131 Nuclear bombardment, 209 planets, 69 Nuclear fission, 212 random, 130 Nuclear force, 127 star clusters, 111 Nuclear reactions stars, 105 energy release, 225, 226 Muon, discovery, 207 lifetime, 224 Muon neutrinos, 243 non-resonant, 229 atmospheric, 243 rate, 223 supergiant stars, 348–349 temperature, 222 N Nuclear transformation, 209, 210 Nanometer, 35 Nucleons, 127 Neap ocean tides, 83 Nucleosynthesis, 216, 339 Nebula, 7 big bang, 353, 354 Nebular hypothesis, 381, 382 stellar, 351, 352 Nebulium, 357 Nucleus, 127, 226, 227 Subject Index 629

Nucleus (cont.) 51 Pegasi, exoplanet, 405, 406 atomic, 127 Penetration probability, protons, 222 binding energy, 226, 227 Perihelion, 72 mass defect, 226 Period-luminosity relation, variable Null geodesic, 469 stars, 475, 476 Number, galaxies, 497 Period-radius relation, variable stars, 475 Number density, galaxies, 502 Photo-absorption coefficient, 175 Nutation, 13, 14 Photoelectric effect, 60 Photon, 59 Photon energy, 60 O Photosphere, 255 O and B stars, triggering gravitational thermal velocity, 132, 133 collapse, 394 Pion, discovery, 208 Oblateness, planets, 119 Planck constant, 30, 45 Obliquity of the ecliptic, 4 Planck mission, 532 Ocean tides, 81 Plane waves, 34 Olbers’ paradox, 493 Planetary nebulae, 412–417 Oort’s constants, 478, 480 age, 415 Open star clusters, 344, 345 bright named, 417 age, 344, 345 central stars, 414 Hertzsprung–Russell diagrams, 347 emission lines, 413, 414 Open universe, 520 formation, 415 Optical depth, 65 physical properties, 414 Optically thick, 66 Planetary rings, origin, 90 Optically thin, 66 Planet-forming disks, 400–402 Optically visible radiation, 38 Planets Orbital motion, 101 albedo, 58 binary stars, 104 atmospheric molecules, 138 planets, 102 composition, 382, 383 Orbits, electron quantized, 168 effective temperature, 55, 56 Origin fastest rotation, 119 chemical elements, 348–353 habitable zone, 57 expanding universe, 523 magnetospheres, 285, 286 novae, 429–433 motion, 69 solar flares, 276 oblate shape, 118 solar winds fast and slow, 274 orbital speed, 102 supernovae, 436–438 rotation, 116–120 Orion Nebula, 359 speed, 69, 70 Oscillating universe, 520 , 56–58 Ozone layer, 145 Plasma, 149, 150 Plasma frequency, 152 Plasma oscillations, 152 P Plerions, 448 Pair annihilation, 207 Plurality of worlds, 400 big bang, 523 Polaris, 6, 10 solar flares, 280 Polarization, starlight, 368, 369 Palomar Sky Survey, 7 Pole Star, 11, 12 Parallax, 51, 293, 294 Polonium, 193 Parsec (pc), 29, 294 Population I stars, 354 Particles Cepheids, 476 energy distribution, 137 Milky Way, 476 speed distribution, 135, 137 variable, 475 Pascal, 141 Population II stars, 354 Peculiar motions, galaxies, 508, 509 globular star clusters, 477 630 Subject Index

variable, 475 R Population III stars, 354 Radar, astronomical unit, 53 Positive beta decay, 201, 207 Radial velocity, 105–107, 180 Positron, 201 Radian, 9, 10 discovery, 206 Radiation, 33 Power, nuclear reactions, 223 absorption, 65 Poynting–Robertson effect, 141 blackbody, 44 Precession, 11–13 emission coefficient, 65 Pressure, 141–145 frequency, 35, 36 cosmic range, 142 scattering, 62, 63 Earth’s atmosphere, 142, 145 thermal, 44 gas, 140, 142 wavelength, 35 magnetic, 141 Radiation constant, 49 radiation, 141 Radiation era, expanding universe, 536 wind, 141 Radiation pressure, 141, 330 Prime Meridian, 2, 16 stars, 311, 313 Principia, 74 Radiation temperature, big bang, 526 Principle of Relativity, 41 Radiation transfer, 65 Procyon B, 327 Radio galaxies, 546, 547 Proper motion, 105, 107 emission lines, 546 Proper time interval, 469 synchrotron radiation, 547 Protons, 127 R136a1, massive star, 312 electrical repulsion, 221 Radio pulsars, 452, 453, 455, 456, 458, 460 physical properties, 129 age, 457 Proton-proton chain, 232–234, 335, 338 Crab Nebula, 449, 450, 458 Proto-planetary disks, 400 luminosity, 457 Protostars, 395, 396 magnetic field strength, 457 Hertzsprung–Russell diagram, 395 periods, 454 lifetime, 388, 389 physical properties, 454 Proxima Centauri, 29, 319 rotational energy, 457 distance, 53, 295, 301 Radio radiation, 64 luminosity, 301 bending by Sun, 95 radius, 301, 307 discovery, 59 temperature, 301 Milky Way, 369, 375 velocity, 119 scintillation, 453 Pulsar, Crab Nebula, 449, 450 supernova remnants, 444 Pulsar.See Radio pulsar or X-ray pulsar Radio telescope, 23 Pulsars, 452–454, 456, 458, 460, 461 Radioactive alpha decay, 194 discovery, 452, 453 Radioactivity, 193 constant, 196 dating, 198 Q nuclear half-life, 197 Quanta, 44 Radium, 193 , 168, 197, 424 Radius atom, 165, 166, 168 Arcturus, 308 degenerate gas, 423–427, 452 atom, 128 radioactive decay, 197 atomic nucleus, 128 Quantum tunneling effect, in Sun, 222 Betelgeuse, 307 Quarks, 127 Earth, 11 Quasars, 549 emission nebula, 360, 365 discovery, 548 gyration, 187 emission lines, 549 H II region, 360, 365 Quasistellar radio sources, 549 Milky Way, 476, 478 Subject Index 631

Radius (cont.) Venus, 118 neutron stars, 451 white dwarf stars, 456 observable universe, 516 Rotational line broadening, 184 Proxima Centauri, 315 Runaway stars, 115–118 stars, 305 Runaway thermonuclear explosion, white Sun, 10, 28, 53 dwarf, 432 universe, 558 Rydberg constant, 167 Radius-mass relation, white dwarf stars, 428 atomic, 172, 173 Radon, 194 Rydberg energy unit, 169 Random motion, 131 Rate, star formation, 542 Rayleigh scattering, 62 S Rayleigh scattering cross section, 62 Sagittarius A*, 484, 485 Rayleigh-Jeans law, 46, 47 Saha ionization equation, 177 Reaction rate, nuclear fusion, 230 Satellites, threat from Sun, 291 Recombination lines, 170, 363 Scattering Recombination radiation, 361, 362 Compton, 64 Recombination time, expanding universe, 539 radiation, 64 Reddening, starlight, 368 Rayleigh, 61 Red giant stars, 306, 320, 326 Thomson, 63 formation, 341 Schwarzschild metric, 468 mass loss, 328 Schwarzschild radius, 467, 468 winds, 328 Scintillations, 453, 454 Redshift, 109, 180 Second generation stars, 354 galaxies, 494 Second law of thermodynamics, 266 Redshift-magnitude diagram, Type Ia super- Second of arc, 9, 10 novae, 555 Seeing, 22 Redshift-magnitude relation, 495 Seyfert galaxies, 545 Reflector, 19, 20 emission lines, 545 Refractor, 19, 20 Sgr A*, 484, 485 Reionization time, expanding universe, 540 SI units, 30 Resolving power, 21 conversion to c.g.s units, 30 Resonance reactions, 343 Sidereal day, 17 Rest mass, 43 Sidereal rotation period, 121 Rest-mass energy, 43 Sidereal time, 17, 18 Right ascension, 5 Singularity Rings, origin, 90 big bang, 523 Robertson–Walker metric, 518 black hole, 469, 470 Roche limit, 90–92 Sirius A, luminosity, 302 Roche lobe, 432 Sirius B, 327, 419 Root mean square speed, 137 gravitational redshift, 421 Rosette Nebula, 359 luminosity, 302 Rotation Sloan Digital Sky Survey, 7, 510, 511 cosmic, 116 Sloan Great Wall, 510, 511 differential, 120 SN 1987A, 439 Earth, 2 neutrino burst, 441 Mercury, 116, 117 progenitor star, 441 Milky Way, 478–481 visible explosion, 441 neutron star, 455 Solar active region, 261 radio pulsar, 456, 458 SOlar and Heliospheric Observatory (SOHO) , stars, 120, 398, 399 251 Sun, 121, 385, 386 Solar constant, 55, 300 velocity, 184 Solar day, 15, 18 632 Subject Index

Solar flares, 276–280 blackbody, 44 accelerated particles, 277 continuum, 44 chromospheric evaporation, 280 electromagnetic, 37, 38 energy, 276 nonthermal radiation, 370 magnetic reconnection, 278, 279 thermal radiation, 46 nuclear reactions, 279 Speed, 71 origin, 277 escape, 77, 99–101, 113, 139, 451 positrons, 280 light, 14, 28, 30, 35, 41 protons - threat to humans, 290 mean, 137 radio bursts, 277, 278 most probable, 135 shock waves, 277 orbital, 102 temperature, 276 planets, 70, 71 white light, 276 root mean square, 137 X-rays, 278, 279 sound, 155 Solar granulation, 249, 250 Speed distribution function, 136 Solar magnetic activity cycle, 259 Speed of light, 14, 28, 30, 35, 41 Solar nebula, 381, 383, 394 Speed of sound, 155 Solar neutrino problem, 240–244 Sphere, gravitational potential energy, 76 Solar neutrinos, detectors, 239 Spheres of ionization, 360 Solar neutrinos, flux, 238, 241 Spiral arms, Milky Way, 482, 483 Solar neutrino unit, 240 , 491 Solar parallax, 51, 52 dark matter, 490, 491 Solar system, formation, 381–387 Spiral nebulae, 491 Solar time, 15, 17 Cepheid variable stars, 488, 489 Solar wind distance, 489 comet tails, 268 recession velocities, 492 discovery, 268 Spitzer Space Telescope (SST) , 25, 401, 496, mass loss from Sun, 273 509, 516 physical properties, 272 Spontaneous transition coefficient, 175 speed of sound, 156, 272 Spring ocean tides, 83 steady, uniform high speed, 274 Sputnik, 153 supersonic, 271 Standard epoch, 13 termination shock, 275, 276 Stars variable, gusty slow speed, 274 age and rotation, 123, 124 Solstice, 8 angular size, 306 Sound, 154 brightest, 296, 297 Sound speed, 155 central temperature, 219, 329 Sound waves, 154 Cepheid variable, 474–476 heat chromosphere, 267 chemical composition, 334 in Sun, 251, 252 classification, 305 Space curvature, 94 color, 303 Space curvature index, 518, 520 convection, 339, 340 Space Telescopes, 25 convective zones, 340 Space velocity, 105, 106 effective temperature, 303 Space weather, 283–292 fate, 310 forecasting , 291, 292 first, 540–544 Special Theory of Relativity, 42, 43, 220, 468 first generation , 354 Spectral classification, stars, 306 formation, 387–400, 543–544 Spectral sequence, 305, 306 formation rate, 543 Spectroheliograph, 159, 162 gravitational redshift, 181, 182, 421 Spectroscopic binary stars, 315, 317 habitable zone, 409 Spectroscopic distance, stars, 322 initial mass distribution, 544 Spectroscopic parallax, stars, 322 initial mass function, 317 Spectrum interferometry, 307 Subject Index 633

Stars (cont.) abundance of elements, 351 largest, 306 active region, 261 luminosity, 299 age, 198, 217 luminosity class, 321 angular extent, 8 mass, 310 central gas pressure, 218 mass distribution, 544 central mass density, 218 mass-luminosity relation, 310, 311 central temperature, 217 most abundant element hydrogen, 179 composition, 160, 161 most massive, 312 convection, 245, 248 motion, 105 convective zone, 246, 247 Population I, II and III, 354 core, 244, 245 pulsation, 327, 475 deflection of starlight, 94 radiation pressure, 312 differential rotation, 120 radius, 306 distance, 51, 52 rapid rotation, 124 effective temperature, 56 red giant, 306, 320, 327, 328 escape velocity, 100, 101, 270 rotation, 120–124, 399 explosions, 276 second generation, 354 fate, 253, 254 spectral classification, 305 Fraunhofer absorption lines, 161–163 spectroscopic distance, 322 free fall time, 397 spectroscopic parallax, 322 gravitational redshift, 181 supergiant, 306, 320, 327, 328 internal mass density, 148, 150 support by gas pressure, 330 internal plasma, 153 support by radiation pressure, 330 internal pressure, 148, 150 temperatures, 303 internal rotation, 123, 124 upper mass limit, 313 internal structure, 245 variable, 475 internal temperature, 148, 150 white dwarf, 320, 327 light bending, 95, 96 Star catalogues, 6 luminosity, 28, 55, 298, 300 Star clusters magnetic field, 258, 259 escape velocity, 113 mass, 28, 80 Hertzsprung–Russell diagrams, 347 mass loss by nuclear fusion, 236 Star time, 17, 18 mass loss by solar wind, 273 Starburst galaxies, 543 most abundant element hydrogen, 179 Starlight, 367, 368 most abundant elements, 164, 165 interstellar absorption, 367 neutrinos, 238–243 polarization, 368, 369 nuclear fusion lifetime, 236 reddening, 368 ocean tides, 81 Stefan-Boltzmann constant, 49 physical properties, 219 Stefan-Boltzmann law, 49, 309, 318 radiation diffusion time, 247 Stellar aberration, 14 radiative zone, 246, 247 Stellar associations, 115 radius, 9, 10, 28, 54 Stellar black holes, 465–469 red hydrogen alpha transition, 176 Stellar nucleosynthesis, 350, 352 rotation, 120, 386 Stellar rotation, 124 rotation velocity about galactic center, 479, Stratosphere, 145 481 Streams, galaxies, 508 secondary nuclear fusion reactions, 235 Strömgren radius, 360, 364 spectrum, 161 Sudbury Neutrino Observatory, 244, 245 temperature, 55, 56 Sun Thomson scattering, 247 absolute visual magnitude, 300 Sunspots, 258 absorption lines, 159 cycle, 258–260 634 Subject Index

Sunspots (cont.) background radiation, 526, 531 origin, 263 big bang, 526 pairs, 261 center of star, 219 Zeeman effect, 188 center of Sun, 217 Sun time, 15, 17 corona, 256 Superfluids, neutron stars, 452 cosmic, 131 Supergiant stars, 306, 320, 327–329 emission nebula, 365 mass loss, 309, 328 H II region, 365 nuclear reactions, 347–349 helium burning, 342 winds, 309, 310, 328 kelvin scale, 28 Supergranulation, 250 kinetic, 133 Super-Kamiokande neutrino detector, 243 nuclear reactions, 221, 222 Super-massive black holes, 550, 551 planets, 56, 57 galactic center, 484, 485 stars, 303 mass, 550 star centers, 329 M 87, 550 Sun visible disk, 55 Supernovae , 433–444 Terrestrial planets, 383 acceleration of cosmic rays, 203 Terrestrial time, 16 binary star system, 437 Thermal bremsstrahlung, 364 energy, 442 Thermal energy, 132 gamma-ray bursts, 552 Thermal equilibrium, 44 gravity-powered iron-catastrophe, 436, Thermal evaporation, 140 438, 439 Thermal motion, Doppler line broadening, 183 historical, 434 Thermal radiation, 44 neutrinos, 441 maximum intensity, 46 nuclear powered, 436, 437 Thermal spectrum, 46 origin, 436–439 Thermal velocity, 132, 139 origin of elements, 341, 344 Thomson scattering, 63 remnants, 443–450 cross section, 63 triggering gravitational collapse, 394 in Sun, 246 types, 435 Three-degree cosmic microwave background Supernova remnants, 443–450 radiation. See Background radiation radio radiation, 444 Tidal friction, 85 types, 444 Tidal locking, 85 X-rays, 443, 445 Tides, 80 Synchronous rotation, 85 Time Synchrotron radiation, 372–375 civil, 15 Crab Nebula, 447–449 dilation, 42, 469 lifetime, 374 free fall, 397 luminosity, 374 international atomic, 15 Milky Way, 374, 375 local sidereal, 17 radio galaxies, 546, 547 sidereal, 17, 18 Synodic rotation period, 122 solar, 15, 17 star, 17, 18 terrestrial, 16 T universal, 16 Tangential velocity, 106–108 Time dilation, 42 Tau lepton, discovery, 211 gravitational, 469 Tau neutrinos, 242, 243 Transition Region and Coronal Explorer Telescope, 20 (TRACE) , 262 resolving power, 21 Troposphere, 145 Temperature Tunneling cross section, 230 accreting material, 463 Two Degree Survey, 510, 511 Subject Index 635

Tycho supernova remnant, 444 Weight, 74 Type Ia supernovae, 436, 437 White dwarf stars, 320, 327, 418–428 redshift-magnitude diagram, 555 carbon and oxygen nuclei, 419 Type II supernovae, 435, 438, 439 discovery, 418 formation, 415 former red giant star, 419 U gravitational redshift, 181, 421 Ultraviolet radiation, 38, 39 in short-period binary systems, 431 Uncertainty principle, 424 magnetic field strength, 422 Universal gravitation, 73 mass density, 420 Universal time, 15 physical properties, 423 Upper mass limit, white dwarf star, 429 radius, 420 Uranium, 194, 195 radius-mass relation, 427 Urca process, 442 rotation period, 455 supernova, 435, 437 upper mass limit, 429 V Wien displacement law, 46 Van Allen radiation belts, 287 Wien tail, 46 Velocity, 71 Wilkinson Microwave Anisotropy Probe Alfvén, 157 (WMAP), 530–532 expansion, 184 Wind pressure, 141 radial, 105–107, 180 Winds rotation, 184 Betelgeuse, 308 space, 105–107 Sun, 268–276 tangential, 105–107 supergiant stars, 307, 309, 328 thermal, 132 Velocity-distance relation, 495 Venus X parallax, 52 X-rays, 38 rotation, 118 black holes, 466, 467 Vernal Equinox, 4 clusters of galaxies, 504 Very Large Telescope Interferometer, 308 Crab Nebula, 447–449 Very Large Telescopes, 21 discovery, 192 Virial theorem, 111 pulsars, 460 Visual binary stars, 314, 315 solar flares, 278, 279 Vogt–Russell theorem, 334 supernova remnants, 444 Voids, galaxies, 510 X-ray pulsars, 460–466 Voyager 1, 275 discovery, 460, 462 Voyager 2, 275 physical properties, 463 Vulcan, 93 VY Canis Majoris, mass loss, 309 VY Cephei A, mass loss, 309 Y Year (yr), 15, 29 Ylem, 353 W Young stars, rapid rotation, 124 Walls, galaxies, 510 Water, interstellar, 379 Wavelength Z colors, 38 Zeeman effect, 183, 187, 188 radiation, 35 interstellar, 188 Waves Sun, 258, 261 Alfvén, 157 sunspots, 188 electromagnetic, 33 Zero age, main sequence, 332