Fundamental Astronomy

507 Pages·2007·20.983 MB·English, Finnish

by  Hannu Karttunen, Pekka Kröger, Heikki Oja, Markku Poutanen, Karl Johan Donner

Fundamental
Astronomy

H. Karttunen
P. Kröger
H. Oja
M. Poutanen
K.J. Donner (Eds.)
Fundamental
Astronomy
FifthEdition
With449Illustrations
Including34ColourPlates
and75ExerciseswithSolutions
123
Dr.HannuKarttunen
UniversityofTurku,TuorlaObservatory,
21500Piikkiö,Finland
e-mail:hannu.karttunen@utu.fi
Dr.PekkaKröger
Isonniitynkatu9C9,00520Helsinki,Finland
e-mail:pekka.kroger@stadia.fi
Dr.HeikkiOja
Observatory,UniversityofHelsinki,
Tähtitorninmäki(POBox14),00014Helsinki,Finland
e-mail:heikki.oja@helsinki.fi
Dr.MarkkuPoutanen
FinnishGeodeticInstitute,
Dept.GeodesyandGeodynamics,
Geodeetinrinne2,02430Masala,Finland
e-mail:markku.poutanen@fgi.fi
Dr.KarlJohanDonner
Observatory,UniversityofHelsinki,
Tähtitorninmäki(POBox14),00014Helsinki,Finland
e-mail:[email protected].fi
ISBN978-3-540-34143-7 5thEdition
SpringerBerlinHeidelbergNewYork Thisworkissubjecttocopyright.Allrightsarereserved,whetherthe
wholeorpartofthematerialisconcerned,specificallytherightsof
ISBN978-3-540-00179-9 4thEdition translation,reprinting,reuseofillustrations,recitation,broadcasting,
Springer-VerlagBerlinHeidelbergNewYork reproductiononmicrofilmorinanyotherway,andstorageindata
banks.Duplicationofthispublicationorpartsthereofispermittedonly
LibraryofCongressControlNumber:2007924821 undertheprovisionsoftheGermanCopyrightLawofSeptember9,
1965,initscurrentversion,andpermissionforusemustalwaysbe
obtainedfromSpringer-Verlag.Violationsareliableforprosecution
undertheGermanCopyrightLaw.
SpringerisapartSpringerScience+BusinessMedia
Coverpicture: TheJamesClerk MaxwellTelescope. Photocredit:
RobinPhillipsandRoyalObservatory,Edinburgh.Imagecourtesyof
www.springer.com
theJamesClerkMaxwellTelescope,MaunaKeaObservatory,Hawaii
Frontispiece: The Horsehead Nebula, officially called Barnard33, ©Springer-VerlagBerlinHeidelberg1987,1994,1996,2003,2007
intheconstellationofOrion,isadensedustcloudontheedgeof
abrightHIIregion.Thephotographwastakenwiththe8.2meter
Theuseofgeneraldescriptivenames,registerednames,trademarks,
Kueyentelescope(VLT2)atParanal.(PhotographEuropeanSouthern
etc.inthispublicationdoesnotimply,evenintheabsenceofaspecific
Observatory)
statement,thatsuchnamesareexemptfromtherelevantprotective
lawsandregulationsandthereforefreeforgeneraluse.
TitleoforiginalFinnishedition:
Tähtitieteenperusteet(Ursanjulkaisuja56)
TypesettingandProduction:
©TähtitieteellinenyhdistysUrsaHelsinki1984,1995,2003
LE-TeX,Jelonek,Schmidt&VöcklerGbR,Leipzig
Coverdesign:ErichKirchner,Heidelberg/WMXDesign,Heidelberg
Sourcesfortheillustrationsaregiveninthecaptionsandmorefully
Layout:SchreiberVIS,Seeheim
attheendofthebook.Mostoftheuncreditedillustrationsare
©UrsaAstronomicalAssociation,Raatimiehenkatu3A2,
Printedonacid-freepaper
00140Helsinki,Finland
SPIN:11685739 55/3180/YL 543210
V
Preface to the Fifth Edition
As the title suggests, this book is about fundamental While we were working on the new edition, the
thingsthatonemightexpecttoremainfairlythesame. InternationalAstronomicalUniondecidedonaprecise
Yetastronomyhasevolvedenormouslyoverthelastfew definitionofaplanet,whichmeantthatthechapteron
years, and only a few chapters of this book have been thesolarsystemhadtobecompletelyrestructuredand
leftunmodified. partlyrewritten.
Cosmology has especially changed very rapidly Overthelastdecade,manynewexoplanetshavealso
from speculations to an exact empirical science and beendiscoveredandthisisonereasonfortheincreasing
this process was happening when we were working interestinanewbranchofscience–astrobiology,which
with the previous edition. Therefore it is understand- nowhasitsownnewchapter.
able that many readers wanted us to expand the In addition, several other chapters contain smaller
chapters on extragalactic and cosmological matters. revisions and many of the previous images have been
We hope that the current edition is more in this replacedwithnewerones.
direction. There are also many revisions and addi-
tions to the chapters on the Milky Way, galaxies, and Helsinki TheEditors
cosmology. December2006
VI
Preface to the First Edition
Themainpurposeofthisbookistoserveasauniversity theeditors;MarkkuPoutanenwrotethechapteronthe
textbook for a first course in astronomy. However, we solar system; Juhani Kyröläinen expanded the chapter
believethattheaudiencewillalsoincludemanyserious on stellar spectra; Timo Rahunen rewrote most of the
amateurs, who often find the popular texts too trivial. chaptersonstellarstructureandevolution;IlkkaTuomi-
Thelackofagoodhandbookforamateurshasbecome nenrevisedthechapterontheSun;KaleviMattilawrote
a problem lately, as more and more people are buying the chapter on interstellar matter; Tapio Markkanen
personalcomputersandneedexact,butcomprehensible, wrotethechaptersonstarclustersandtheMilkyWay;
mathematicalformalismfortheirprograms.Thereader KarlJohanDonnerwrotethemajorpartofthechapter
of this book is assumed to have only a standard high- on galaxies; Mauri Valtonen wrote parts of the galaxy
schoolknowledgeofmathematicsandphysics(asthey chapter,and,incollaborationwithPekkaTeerikorpi,the
aretaughtinFinland);everythingmoreadvancedisusu- chapteroncosmology.Finally,theresulting,somewhat
ally derived step by step fromsimple basic principles. inhomogeneous, material was made consistent by the
The mathematical background needed includes plane editors.
trigonometry, basic differential and integral calculus, The English text was written by the editors, who
and(onlyinthechapterdealingwithcelestialmechan- translatedpartsoftheoriginalFinnishtext,andrewrote
ics)somevectorcalculus.Somemathematicalconcepts otherparts,updatingthetextandcorrectingerrorsfound
thereadermaynotbefamiliarwitharebrieflyexplained in the original edition. The parts of text set in smaller
in the appendices or can be understood by studying print are less important material that may still be of
the numerous exercises and examples. However, most interesttothereader.
of the book can be read with very little knowledge of Fortheillustrations,wereceivedhelpfromVeikko
mathematics,andevenifthereaderskipsthemathemat- Sinkkonen,MirvaVuoriandseveralobservatories and
ically more involved sections, (s)he should get a good individuals mentioned in the figure captions. In the
overviewofthefieldofastronomy. practical work, we were assisted by Arja Kyröläinen
Thisbookhasevolvedinthecourseofmanyyears and Merja Karsma. A part of the translation was read
andthroughtheworkofseveralauthorsandeditors.The and corrected by Brian Skiff. We want to express our
firstversionconsistedoflecturenotesbyoneoftheedi- warmestthankstoallofthem.
tors(Oja).Thesewerelatermodifiedandaugmentedby FinancialsupportwasgivenbytheFinnishMinistry
the other editors and authors. Hannu Karttunen wrote ofEducationandSuomalaisenkirjallisuudenedistämis-
the chapters on spherical astronomy and celestial me- varojen valtuuskunta (a foundation promoting Finnish
chanics; Vilppu Piirola added parts to the chapter on literature),towhomweexpressourgratitude.
observationalinstruments,andGöranSandellwrotethe
partaboutradioastronomy;chaptersonmagnitudes,ra- Helsinki TheEditors
diationmechanismsandtemperaturewererewrittenby June1987
VII
Contents
1. Introduction 1.1 TheRoleofAstronomy ........................................ 3
1.2 AstronomicalObjectsofResearch ............................. 4
1.3 TheScaleoftheUniverse ...................................... 8
2. SphericalAstronomy 2.1 SphericalTrigonometry ........................................ 11
2.2 TheEarth ....................................................... 14
2.3 TheCelestialSphere ........................................... 16
2.4 TheHorizontalSystem ......................................... 16
2.5 TheEquatorialSystem ........................................ 17
2.6 RisingandSettingTimes ....................................... 20
2.7 TheEclipticSystem ............................................ 20
2.8 TheGalacticCoordinates ...................................... 21
2.9 PerturbationsofCoordinates ................................... 21
2.10 PositionalAstronomy .......................................... 25
2.11 Constellations .................................................. 29
2.12 StarCataloguesandMaps ...................................... 30
2.13 SiderealandSolarTime ........................................ 32
2.14 AstronomicalTimeSystems ................................... 34
2.15 Calendars ....................................................... 38
2.16 Examples ....................................................... 41
2.17 Exercises ........................................................ 45
3. Observations 3.1 ObservingThroughtheAtmosphere ........................... 47
andInstruments 3.2 OpticalTelescopes ............................................. 49
3.3 DetectorsandInstruments ..................................... 64
3.4 RadioTelescopes ............................................... 69
3.5 OtherWavelengthRegions ..................................... 76
3.6 OtherFormsofEnergy ......................................... 79
3.7 Examples ....................................................... 82
3.8 Exercises ........................................................ 82
4. PhotometricConcepts 4.1 Intensity,FluxDensityandLuminosity ....................... 83
andMagnitudes 4.2 ApparentMagnitudes .......................................... 85
4.3 MagnitudeSystems ............................................ 86
4.4 AbsoluteMagnitudes ........................................... 88
4.5 ExtinctionandOpticalThickness .............................. 88
4.6 Examples ....................................................... 91
4.7 Exercises ........................................................ 93
5. RadiationMechanisms 5.1 RadiationofAtomsandMolecules ............................ 95
5.2 TheHydrogenAtom ........................................... 97
5.3 LineProfiles .................................................... 99
5.4 QuantumNumbers,SelectionRules,PopulationNumbers ... 100
5.5 MolecularSpectra .............................................. 102
Contents
VIII
5.6 ContinuousSpectra ............................................. 102
5.7 BlackbodyRadiation ........................................... 103
5.8 Temperatures ................................................... 105
5.9 OtherRadiationMechanisms .................................. 107
5.10 RadiativeTransfer .............................................. 108
5.11 Examples ....................................................... 109
5.12 Exercises ........................................................ 111
6. CelestialMechanics 6.1 EquationsofMotion ........................................... 113
6.2 SolutionoftheEquationofMotion ............................ 114
6.3 EquationoftheOrbitandKepler’sFirstLaw ................. 116
6.4 OrbitalElements ............................................... 116
6.5 Kepler’sSecondandThirdLaw ............................... 118
6.6 SystemsofSeveralBodies ..................................... 120
6.7 OrbitDetermination ............................................ 121
6.8 PositionintheOrbit ............................................ 121
6.9 EscapeVelocity ................................................ 123
6.10 VirialTheorem ................................................. 124
6.11 TheJeansLimit ................................................ 125
6.12 Examples ....................................................... 126
6.13 Exercises ........................................................ 129
7. TheSolarSystem 7.1 PlanetaryConfigurations ....................................... 133
7.2 OrbitoftheEarthandVisibilityoftheSun .................... 134
7.3 TheOrbitoftheMoon ......................................... 135
7.4 EclipsesandOccultations ...................................... 138
7.5 TheStructureandSurfacesofPlanets.......................... 140
7.6 AtmospheresandMagnetospheres ............................. 144
7.7 Albedos ......................................................... 149
7.8 Photometry,PolarimetryandSpectroscopy ................... 151
7.9 ThermalRadiationofthePlanets .............................. 155
7.10 Mercury ......................................................... 155
7.11 Venus ........................................................... 158
7.12 TheEarthandtheMoon ....................................... 161
7.13 Mars ............................................................ 168
7.14 Jupiter .......................................................... 171
7.15 Saturn ........................................................... 178
7.16 UranusandNeptune ............................................ 181
7.17 MinorBodiesoftheSolarSystem ............................. 186
7.18 OriginoftheSolarSystem ..................................... 197
7.19 Examples ....................................................... 201
7.20 Exercises ........................................................ 204
8. StellarSpectra 8.1 MeasuringSpectra ............................................. 207
8.2 TheHarvardSpectralClassification ........................... 209
8.3 TheYerkesSpectralClassification ............................. 212
8.4 PeculiarSpectra ................................................ 213
8.5 TheHertzsprung--RussellDiagram ............................ 215
8.6 ModelAtmospheres ............................................ 216
Contents
IX
8.7 WhatDotheObservationsTellUs? ........................... 217
8.8 Exercise ......................................................... 219
9. BinaryStars 9.1 VisualBinaries ................................................. 222
andStellarMasses 9.2 AstrometricBinaryStars ....................................... 222
9.3 SpectroscopicBinaries ......................................... 222
9.4 PhotometricBinaryStars ...................................... 224
9.5 Examples ....................................................... 226
9.6 Exercises ........................................................ 227
10.StellarStructure 10.1 InternalEquilibriumConditions ............................... 229
10.2 PhysicalStateoftheGas ....................................... 232
10.3 StellarEnergySources ......................................... 233
10.4 StellarModels .................................................. 237
10.5 Examples ....................................................... 240
10.6 Exercises ........................................................ 242
11.StellarEvolution 11.1 EvolutionaryTimeScales ...................................... 243
11.2 TheContractionofStarsTowardstheMainSequence ........ 244
11.3 TheMainSequencePhase ..................................... 246
11.4 TheGiantPhase ................................................ 249
11.5 TheFinalStagesofEvolution ................................. 252
11.6 TheEvolutionofCloseBinaryStars .......................... 254
11.7 ComparisonwithObservations ................................ 255
11.8 TheOriginoftheElements .................................... 257
11.9 Example ........................................................ 259
11.10 Exercises ........................................................ 260
12.TheSun 12.1 InternalStructure ............................................... 263
12.2 TheAtmosphere ................................................ 266
12.3 SolarActivity ................................................... 270
12.4 Example ........................................................ 276
12.5 Exercises ........................................................ 276
13.VariableStars 13.1 Classification ................................................... 280
13.2 PulsatingVariables ............................................. 281
13.3 EruptiveVariables .............................................. 283
13.4 Examples ....................................................... 289
13.5 Exercises ........................................................ 290
14.CompactStars 14.1 WhiteDwarfs ................................................... 291
14.2 NeutronStars ................................................... 292
14.3 BlackHoles ..................................................... 298
14.4 X-rayBinaries .................................................. 302
14.5 Examples ....................................................... 304
14.6 Exercises ........................................................ 305
15.TheInterstellarMedium 15.1 InterstellarDust ................................................ 307
15.2 InterstellarGas ................................................. 318
15.3 InterstellarMolecules .......................................... 326
15.4 TheFormationofProtostars.................................... 329