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ASTROPHYSICS IN 2006 Virginia Trimble1, Markus J. Aschwanden2, and Carl J. Hansen3 1 Department of Physics and Astronomy, University of California, Irvine, CA 92697-4575, Las Cumbres Observatory, Santa Barbara, CA: ([email protected]) 2 Lockheed Martin Advanced Technology Center, Solar and Astrophysics Laboratory, Organization ADBS, Building 252, 3251 Hanover Street, Palo Alto, CA 94304: ([email protected]) 3 JILA, Department of Astrophysical and Planetary Sciences, University of Colorado, Boulder CO 80309: ([email protected]) Received ... : accepted ... Abstract. The fastest pulsar and the slowest nova; the oldest galaxies and the youngest stars; the weirdest life forms and the commonest dwarfs; the highest energy particles and the lowest energy photons. These were some of the extremes of Astrophysics 2006. We attempt also to bring you updates on things of which there is currently only one (habitable planets, the Sun, and the universe) and others of which there are always many, like meteors and molecules, black holes and binaries. Keywords: cosmology: general, galaxies: general, ISM: general, stars: general, Sun: gen- eral, planets and satellites: general, astrobiology CONTENTS 1. Introduction 6 1.1 Up 6 1.2 Down 9 1.3 Around 10 2. Solar Physics 12 2.1 The solar interior 12 2.1.1 From neutrinos to neutralinos 12 2.1.2 Global helioseismology 12 2.1.3 Local helioseismology 12 2.1.4 Tachocline structure 13 arXiv:0705.1730v1 [astro-ph] 11 May 2007 2.1.5 Dynamo models 14 2.2 Photosphere 15 2.2.1 Solar radius and rotation 15 2.2.2 Distribution of magnetic fields 15 2.2.3 Magnetic flux emergence rate 15 2.2.4 Photospheric motion of magnetic fields 16 2.2.5 Faculae production 16 2.2.6 The photospheric boundary of magnetic fields 17 2.2.7 Flare prediction from photospheric fields 17 c 2008 Springer Science + Business Media. Printed in the USA. ms.tex; 1/02/2008; 6:36; p.1 2 TRIMBLE ET AL. 2.2.8 Sunspots 17 2.3 Chromosphere and transition region 18 2.3.1 Chromospheric abundances 18 2.3.2 Heating of the chromosphere 18 2.3.3 Chromospheric oscillations 19 2.3.4 Microflaring in the transition region 20 2.4 Corona 21 2.4.1 Coronal atomic physics 21 2.4.2 The coronal magnetic field 21 2.4.3 Magnetic helicity 22 2.4.4 Elementary and composite coronal loops 23 2.4.5 MHD Modeling of coronal loops 23 2.4.6 Coronal heating 24 2.4.7 Coronal oscillations and waves 25 2.4.8 Coronal holes 26 2.4.9 Coronal streamers 26 2.5 Filaments and prominences 27 2.5.1 Quiescent filaments 27 2.5.2 Eruptive filaments 28 2.6 Flares 28 2.6.1 Preflare magnetic field configuration 28 2.6.2 Magnetic field change during flares 29 2.6.3 Magnetic reconnection 29 2.6.4 Particle accleration 30 2.6.5 RHESSI observations 31 2.6.6 Oscillations and waves in flares 32 2.6.7 Self-organized criticality in solar flares 33 2.7 Coronal mass ejections (CMEs) 33 2.7.1 CME initiation and magnetic field configuration 33 2.7.2 Propagation of CMEs 34 2.7.3 CME-initiated waves 35 2.7.4 Geo-effectiveness of CMEs 35 2.7.5 Solar energetic particles 36 2.8 Heliosphere 37 2.8.1 Solar wind 37 2.8.2 Interplanetary radio bursts 38 2.8.3 Termination shock 38 2.9 Solar-Terrestrial relations 38 2.9.1 Global warming, ozone, and cloud-free skys 39 2.9.2 Geomagnetic storms 39 2.9.3 Solar activity cycle 39 3. Galaxies near and far 40 3.1 Home sweet home: The Milky Way and Local Group 40 ms.tex; 1/02/2008; 6:36; p.2 ASTROPHYSICS IN 2006 3 3.2 The Local Group grows 41 3.3 MW 6= M31 42 3.4 Minor members 43 3.5 The Milky Way and other spirals 44 3.5.1 Arms 44 3.5.2 Bars 45 3.5.3 Disks 45 3.5.4 Stellar populations 46 3.5.5 Bulges and halos 46 3.6 Interactions 47 3.7 The first galaxies and how they grow 48 3.8 Broad brushes 49 3.9 Some special galaxies 52 3.10 Residual problems 54 3.11 Clusters of galaxies 55 3.12 Between the galaxies 57 4. All turtles that on Earth do dwell 58 4.1 Inside the Earth 58 4.2 Atmospheres and climates 60 4.3 Other species 61 4.4 And the wisdom to know the difference 62 4.5 Let us now praise famous persons 66 4.6 Oh, dear. I’m really rather glad I didn’t say that! 68 4.6.1 The minor awards 69 4.6.2 The minor malfunctions 70 4.6.3 With a little help from our friends 72 5. Interstellar matter, star formation, young stellar objects, and chemical evolution 74 5.1 The interstellar medium 74 5.2 Star formations 77 5.2.1 First things and modes 78 5.2.2 Changes with redshift 78 5.2.3 Initial conditions and their causes 79 5.2.4 The initial mass function 80 5.2.5 Stars of large and small masses 81 5.3 Young stellar objects 81 5.4 Chemical evolutions 82 5.4.1 The largest scales 83 5.4.2 Galaxies and stellar populations 83 5.4.3 Individual processes and nuclides 85 6. Stars 87 6.1 Location, location, location 87 6.2 Ordinary things about ordinary stars 88 ms.tex; 1/02/2008; 6:36; p.3 4 TRIMBLE ET AL. 6.3 Stellar structure and evolution calculations 89 6.4 The chemically peculiar stars 91 6.5 Brown dwarfs 92 6.6 Real time stellar evolution 93 6.7 Motions in space 95 6.8 Stellar rotation and activity 96 6.9 Pulsating stars 98 6.10 Sad tails of the deaths of stars 100 6.11 White dwarfs 101 6.12 Single black holes 103 7. Astrobiology 104 7.1 Reviews, Books, and Awards 104 7.2 SETI Lives 105 7.2.1 The ATA 106 7.2.2 BOINC 107 7.2.3 The Drake equation 108 7.3 Updates, Mendings, and Miscellaneous 109 7.3.1 Water on Mars? 109 7.3.2 Archeal musings 109 7.3.3 Let’s have a little fun 110 8. More than 1 but less than 106 111 8.1 Binary stars 111 8.1.1 Binaries in stellar populations 111 8.1.2 Binary statistics and triples 112 8.1.3 Binary evolution 114 8.1.4 Cataclysmic variables 115 8.1.5 Binary black holes 117 8.2 Star clusters 118 8.2.1 Open clusters, moving groups, and star streams 118 8.2.2 KREDOS 119 8.2.3 Globular Clusters 120 8.3 Other sorts of star clusters 123 9. Silent, upon an peak in DARIEN: Exo and endo planets 124 9.1 Exoplanets 124 9.1.1 Extrema 124 9.1.2 Search methods 125 9.1.3 Statistical properties, hosts vs. planets 126 9.1.4 Formation mechanisms 127 9.2 Endoplanets and the rest of the solar system 128 9.2.1 Dust and meteors 128 9.2.2 Comets and asteroids 129 9.2.3 Moons 132 9.2.4 Major planets, general confusion, and colonel Deshafy 134 ms.tex; 1/02/2008; 6:36; p.4 ASTROPHYSICS IN 2006 5 10. Biggish bangs 136 10.1 Supernovae, their remnants, and gamma ray bursts 136 10.1.1 Supernovae 136 10.1.2 Some other things about supernovae 138 10.1.3 Supernovae remnants 139 10.1.4 Gamma ray bursters 140 10.2 The pulsars of the nations 141 10.2.1 More pulsars singles and singularities 142 10.2.2 Binary neutron stars 145 10.3 Black blogs: QSOs, AGNs, and all 147 10.3.1 More certain answers 147 10.3.2 Less certain answers 149 10.3.3 An absorbing topic 151 11. OAO 152 11.1 Countdown 152 11.2 First 159 11.3 Extrema 161 11.4 Astronomical extrema 162 11.5 Familiar physics, expected effects, and wonderful widgets 165 11.5.1 Physical principles 165 11.5.2 Processes 167 11.5.3 Catalogs 168 11.5.4 Sites and observatories 169 11.5.5 Widgets 169 12. Cosmology 172 12.1 A child’s garden of cosmological models 172 12.2 The conventional universe 176 12.3 Distance indicators and gravitational lensing 179 12.4 Dark matter 180 12.5 Dark energy 182 12.6 The backgrounds 182 12.7 Cosmic rays 186 12.8 Very large scale structure and streaming 187 13. Misteaks were made 190 13.1 We done it 190 13.2 They done it 191 Acknowledgements 195 References 196-239 ms.tex; 1/02/2008; 6:36; p.5 6 TRIMBLE ET AL. 1. INTRODUCTION Astrophysics in 2006 modifies a long tradition by moving to a new journal, which you hold in your (real or virtual) hands. The fifteen previous articles in the series are referenced occasionally as Ap91 to Ap05 below and appeared in volumes 104-118 of Publications of the Astronomical Society of the Pacific. The ground rules are fairly simple: we read a lot, decide what we think is important, and tell you about it. Used in compiling Sections 3-6 and 8- 13 were the issues that arrived as paper between 1 October 2005 and 20 September 2006 of Nature, Physical Review Letters, Science, Astrophysi- cal Journal (plus Letters and Supplements Series), Monthly Notices of the Royal Astronomical Society, Astronomy and Astrophysics, Astronomical Journal, Acta Astronomica, Revista Mexicana Astronomia y Astrofisica, Astrophysics and Space Science, Astronomy Reports, Astronomy Letters, Astronomische Nachrichten, Publications of the Astronomical Society of Japan, Publications of the Astronomical Society of the Pacific, Journal of Astrophysics and Astronomy, Bulletin of the Astronomical Society of India, Contributions of the Astronomical Observatory Skalnate Pleso, and IAU Circulars.
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