Chapter 2
Astronomy and astrophysics
Links to WWW resourcesThe Solar System.......................................... 25 The Sun................................................. 25 Solar System elemental abundances....................... 30 The planets (physical elements)......................... 31 The planets (orbital elements).......................... 32 Natural satellites in the Solar System.................. 33 Short period comets..................................... 36 Principal meteor streams................................ 37 Stars..................................................... 38 Star charts............................................. 38 Constellations.......................................... 40 The brightest stars..................................... 44 The 100 visually brightest stars........................ 45 Stars within 5 pc....................................... 50 Nearest stars........................................... 52 Stars of large proper motion............................ 53 The 21 fastest pulsars.................................. 54 Pulsars................................................. 56 Binary radio pulsars.................................... 58 OB associations......................................... 59 Orbital elements of binary stars........................ 61 Classification of variable stars........................ 62 Galactic supernova remnants............................. 64 Henry Draper spectral classification.................... 64 Spectral type and luminosity class...................... 65 Hertzsprung-Russell diagram............................. 66 Infrared and visible spectral features.................. 67 The main sequence....................................... 68 Giant stars............................................. 70 Classification and absolute magnitude of stars.......... 71 Stellar mass, luminosity, radius and density............ 72 Present-day mass function............................... 74 Star number densities................................... 76 Relative number of stars................................ 78 Integrated star light................................... 78 Mean star density vs visual magnitude................... 79 Star counts............................................. 80 Luminosity functions.................................... 80 Parameters of the interstellar gas...................... 81 Galaxies.................................................. 82 Properties of the galaxy................................ 82 The local group......................................... 83 Hubble's classification................................. 84 Nearby extragalactic objects............................ 84 Selected brighter galaxies.............................. 85 Named galaxies.......................................... 86 Representative active galactic nuclei................... 87 Objects with large redshifts............................ 90 Prominent clusters of galaxies.......................... 91 Energy content of constituents of space................... 93 Mass-radius-density data for astronomical objects......... 94 The Messier catalog....................................... 95 Astronomical photometry................................... 98 Standard photometric systems............................100 Interstellar reddening..................................103 Absolute magnitude......................................105 Moon, night sky, sun, and planetary brightness..........105 Spherical astronomy.......................................107 Time....................................................107 The celestial sphere....................................109 Celestial coordinates...................................110 The Zodiac..............................................110 Astronomical coordinate transformations.................111 Approximate reduction of astronomical coordinates.......113 Major ground-based astronomical facilities................114 The Hubble Space Telescope................................120 Description of the Hubble Space Telescope...............121 Glossary of astronomical terms............................124 Bibliography..............................................140