Spectral Atlas for Amateur Astronomers: A Guide to the Spectra of Astronomical Objects and Terrestrial Light Sources

297 Pages·2017·16.09 MB·English

by  Richard Walker

Spectral Atlas for Amateur Astronomers
A Guideto the Spectraof Astronomical Objectsand TerrestrialLightSources
Featuringdetailedcommentsonspectralprofilesofmorethan100astronomicalobjects,incolor,thisspectral
guide documents most of the important and spectroscopically observable objects accessible with typical
amateur equipment. It allows you to read and interpret the recorded spectra of the main stellar classes, as
well as most of the steps from protostars through to the final stages of stellar evolution as planetary nebulae,
whitedwarfsorthedifferenttypesofsupernovae.Italsopresentsintegratedspectraofstellarclusters,galaxies
andquasars,andthereferencespectraofsometerrestriallightsources,forcalibrationpurposes.Whetherused
as the principal reference for comparing with your recorded spectra or for inspiring independent observing
projects, this atlas provides a breathtaking view into our Universe’s past. The atlas is accompanied and
supplemented by Spectroscopy for Amateur Astronomers, which explains in detail the methods for recording,
processing, analyzing and interpreting your spectra.
Richard Walker has been an avid astronomer since he was aged 12. He spent his career in civil engineering,
planninglargeprojectssuchaspowerplants,damsandtunnels.Nowretired,inthelast10yearshehasfocused
increasingly on stellar astronomy and on the indispensable key to this topic – spectroscopy. He undertook a
large observing project to record and document the spectra of the most important astronomical objects, and
chose to share this gathered information for the benefit of other amateurs worldwide. The Spectral Atlas
and Spectroscopy for Amateur Astronomers are the fruits of his labor. He lives near Zürich, in Switzerland.

Spectral Atlas for Amateur
Astronomers
A Guide to the Spectra of Astronomical Objects
and Terrestrial Light Sources
Richard Walker
Amateurastronomer,Switzerland
UniversityPrintingHouse,CambridgeCB28BS,UnitedKingdom
OneLibertyPlaza,20thFloor,NewYork,NY10006,USA
477WilliamstownRoad,PortMelbourne,VIC3207,Australia
4843/24,2ndFloor,AnsariRoad,Daryaganj,Delhi–110002,India
79AnsonRoad,#06–04/06,Singapore079906
CambridgeUniversityPressispartoftheUniversityofCambridge.
ItfurtherstheUniversity’smissionbydisseminatingknowledgeinthepursuitof
education,learning,andresearchatthehighestinternationallevelsofexcellence.
www.cambridge.org
Informationonthistitle:www.cambridge.org/9781107165908
©RichardWalker2017
Thispublicationisincopyright.Subjecttostatutoryexception
andtotheprovisionsofrelevantcollectivelicensingagreements,
noreproductionofanypartmaytakeplacewithoutthewritten
permissionofCambridgeUniversityPress.
Firstpublished2017
PrintedintheUnitedKingdombyClays,(cid:31)St(cid:31)Ives(cid:31)plc
AcatalogasrecordforthispublicationisavailablefromtheBritishLibrary.
LibraryofCongressCataloging-in-PublicationData
Names:Walker,Richard,1951-
Title:Spectralatlasforamateurastronomers:aguidetothespectraofastronomicalobjects
andterrestriallightsources/RichardWalker,amateurastronomer,Switzerland.
Description:Cambridge:CambridgeUniversityPress,2017.|Includesbibliographicalreferencesandindexes.
Identifiers:LCCN2016036435|ISBN9781107165908(Hardback:alk.paper)
Subjects:LCSH:Stars–Spectra–Atlases.|Stars–Atlases.|Astronomy–Charts,diagrams,etc.|
Stars–Observers’manuals.|Amateurastronomy–Observers’manuals.|Spectrumanalysis.|Largetypebooks.
Classification:LCCQB883.W2772017|DDC522/.67–dc23LCrecordavailableathttps://lccn.loc.gov/2016036435
ISBN978-1-107-16590-8Hardback
Alsoavailableaspartofatwovolumeset:ISBN978-1-316-64256-6Twohardbackbooks
CambridgeUniversityPresshasnoresponsibilityforthepersistenceoraccuracy
ofURLsforexternalorthird-partyInternetWebsitesreferredtointhispublication
anddoesnotguaranteethatanycontentonsuchWebsitesis,orwillremain,
accurateorappropriate.
Spectral Atlas for Amateur Astronomers
A Guideto the Spectraof Astronomical Objectsand TerrestrialLightSources
Featuringdetailedcommentsonspectralprofilesofmorethan100astronomicalobjects,incolor,thisspectral
guide documents most of the important and spectroscopically observable objects accessible with typical
amateur equipment. It allows you to read and interpret the recorded spectra of the main stellar classes, as
well as most of the steps from protostars through to the final stages of stellar evolution as planetary nebulae,
whitedwarfsorthedifferenttypesofsupernovae.Italsopresentsintegratedspectraofstellarclusters,galaxies
andquasars,andthereferencespectraofsometerrestriallightsources,forcalibrationpurposes.Whetherused
as the principal reference for comparing with your recorded spectra or for inspiring independent observing
projects, this atlas provides a breathtaking view into our Universe’s past. The atlas is accompanied and
supplemented by Spectroscopy for Amateur Astronomers, which explains in detail the methods for recording,
processing, analyzing and interpreting your spectra.
Richard Walker has been an avid astronomer since he was aged 12. He spent his career in civil engineering,
planninglargeprojectssuchaspowerplants,damsandtunnels.Nowretired,inthelast10yearshehasfocused
increasingly on stellar astronomy and on the indispensable key to this topic – spectroscopy. He undertook a
large observing project to record and document the spectra of the most important astronomical objects, and
chose to share this gathered information for the benefit of other amateurs worldwide. The Spectral Atlas
and Spectroscopy for Amateur Astronomers are the fruits of his labor. He lives near Zürich, in Switzerland.

Spectral Atlas for Amateur
Astronomers
A Guide to the Spectra of Astronomical Objects
and Terrestrial Light Sources
Richard Walker
Amateurastronomer,Switzerland
UniversityPrintingHouse,CambridgeCB28BS,UnitedKingdom
OneLibertyPlaza,20thFloor,NewYork,NY10006,USA
477WilliamstownRoad,PortMelbourne,VIC3207,Australia
4843/24,2ndFloor,AnsariRoad,Daryaganj,Delhi–110002,India
79AnsonRoad,#06–04/06,Singapore079906
CambridgeUniversityPressispartoftheUniversityofCambridge.
ItfurtherstheUniversity’smissionbydisseminatingknowledgeinthepursuitof
education,learning,andresearchatthehighestinternationallevelsofexcellence.
www.cambridge.org
Informationonthistitle:www.cambridge.org/9781107165908
©RichardWalker2017
Thispublicationisincopyright.Subjecttostatutoryexception
andtotheprovisionsofrelevantcollectivelicensingagreements,
noreproductionofanypartmaytakeplacewithoutthewritten
permissionofCambridgeUniversityPress.
Firstpublished2017
PrintedintheUnitedKingdombyClays,(cid:31)St(cid:31)Ives(cid:31)plc
AcatalogasrecordforthispublicationisavailablefromtheBritishLibrary.
LibraryofCongressCataloging-in-PublicationData
Names:Walker,Richard,1951-
Title:Spectralatlasforamateurastronomers:aguidetothespectraofastronomicalobjects
andterrestriallightsources/RichardWalker,amateurastronomer,Switzerland.
Description:Cambridge:CambridgeUniversityPress,2017.|Includesbibliographicalreferencesandindexes.
Identifiers:LCCN2016036435|ISBN9781107165908(Hardback:alk.paper)
Subjects:LCSH:Stars–Spectra–Atlases.|Stars–Atlases.|Astronomy–Charts,diagrams,etc.|
Stars–Observers’manuals.|Amateurastronomy–Observers’manuals.|Spectrumanalysis.|Largetypebooks.
Classification:LCCQB883.W2772017|DDC522/.67–dc23LCrecordavailableathttps://lccn.loc.gov/2016036435
ISBN978-1-107-16590-8Hardback
Alsoavailableaspartofatwovolumeset:ISBN978-1-316-64256-6Twohardbackbooks
CambridgeUniversityPresshasnoresponsibilityforthepersistenceoraccuracy
ofURLsforexternalorthird-partyInternetWebsitesreferredtointhispublication
anddoesnotguaranteethatanycontentonsuchWebsitesis,orwillremain,
accurateorappropriate.
CONTENTS
Preface page xi 4.4 “Early”and “Late”Spectral Types 15
Acknowledgements xiii 4.5 Temperature Sequence of the Harvard
Classification System 15
1 4.6 RoughDetermination of the One-Dimensional
Spectral Class 15
Directory of Plates 1
4.7 Flowcharts for Estimation of the SpectralClass 16
4.8 Further Criteria for Estimation of the
2
Spectral Class 16
Selection, Processing and Presentation 4.9 The Two-Dimensional MK (Morgan–Keenan)or
of the Spectra 7 Yerkes Classification System 18
4.10 Effect of the Luminosity Class on the
2.1 Selection of Spectra 7
Line Width 18
2.2 Recordingand Resolution of the Spectra 7
4.11 Suffixes, Prefixes and Special Classes 19
2.3 Processing of the Spectra 7
4.12 Statistical Distribution of Spectral Types to the
2.4 Calibration of theWavelength 8
Main Sequence Stars 20
2.5 Display of the Intensity Scale and Normalization
of the Profiles 8
5
2.6 Identification and Labeling of the Spectral Lines 8
2.7 Presentation 9 Spectral Class O 23
2.8 Object Coordinates 9
5.1 Overview 23
2.9 Distances 9
5.2 Parametersof the Late to Early O-Class Stars 24
5.3 Spectral Characteristics of the O Class 24
3 5.4 General Remarks on the Classification of O Stars 24
Terms, Definitions and Abbreviations 10 5.5 Comments on ObservedSpectra 24
3.1 Designation and Parameters of the Stars 10
6
3.2 Galactic Nebulae and Star Clusters 10
3.3 Extragalactic Objects 10 Spectral Class B 30
3.4 Labeling of the H-Balmer series 10
6.1 Overview 30
3.5 Labeling of Elements and Ions 10
6.2 Parametersof the Late to Early B-ClassStars 30
3.6 Abbreviations, Symbols and Common Units 10
6.3 Spectral Characteristics of the BClass 30
6.4 Comments on ObservedSpectra 31
4
7
Overview and Characteristics of Stellar
Spectral Classes 13 Spectral Class A 36
4.1 PreliminaryRemarks 13
7.1 Overview 36
4.2 The Fraunhofer Lines 13
7.2 Parametersof the Late to Early A-Class Stars 36
4.3 Further Development Steps: The Five
7.3 Spectral Characteristics of the A Class 36
Secchi Classes 14
7.4 Comments on ObservedSpectra 37
vi Contents
8 14
Spectral Class F 42 Spectral Class S on the AGB 72
8.1 Overview 42 14.1 Overview and Spectral Characteristics 72
8.2 Parameters of the Late to Early F-Class Stars 42 14.2 The Boeshaar–Keenan S-Classification System 72
8.3 Spectral Characteristics of theF Class 42 14.3 “Intrinsic”and “Extrinsic”or“Symbiotic”
8.4 Commentson Observed Spectra 42 SStars 72
14.4 Hints for the Observation of S-Class Stars 73
9 14.5 Commentson ObservedSpectra 73
Spectral Class G 46
15
9.1 Overview 46
9.2 Parameters of the Late to Early G-Class Stars 46 Carbon Stars on the AGB 78
9.3 Spectral Characteristics of theG Class 46 15.1 Overview and Spectral Characteristics 78
9.4 Commentson Observed Spectra 47 15.2 CompetingClassification Systems 78
15.3 The Morgan–Keenan (MK) C-System 79
10 15.4 The Revised Keenan 1993 System 79
15.5 Connection of the Subclasses to the Evolution
Spectral Class K 53
of Carbon Stars 80
10.1 Overview 53 15.6 Merrill–SanfordBands (MS) 80
10.2 Parameters of the Late to Early K-Class Stars 53 15.7 Commentson ObservedSpectra 80
10.3 Spectral Characteristics of theK Class 54
10.4 Commentson Observed Spectra 55 16
Post-AGB Stars and White Dwarfs 85
11
16.1 Position of Post-AGB Stars in Stellar
Spectral Class M 61 Evolution 85
11.1 Overview 61 16.2 Post-AGB Stars 85
11.2 Parameters of the Late to Early M-Class Stars 61 16.3 Spectral Features of Post-AGB Stars 85
11.3 Spectral Characteristics of theM Class 62 16.4 White Dwarfs 85
11.4 Commentson Observed Spectra 62 16.5 Spectral Characteristics and Special Features
of White Dwarfs 86
12 16.6 Classification System byMcCook and Sion 86
16.7 Commentson ObservedSpectra 86
Spectral Sequence on the AGB 67
12.1 Evolution of Stars in the Post-Main 17
Sequence Stage 67
Wolf–Rayet Stars 89
12.2 TheSpectral Sequence of the Mira Variables
on theAGB 67 17.1 Overview 89
17.2 Spectral Characteristics and Classification 89
13 17.3 Classification System for WR Stars in the Optical
Spectral Range 90
M(e) Stars on the AGB 69 17.4 The WR Phase in Stellar Evolution 91
13.1 Overview 69 17.5 Analogies and Differences to the Central Stars
13.2 Spectral Characteristics of theM(e) Stars of Planetary Nebulae 91
on theAGB 69 17.6 Commentson ObservedSpectra of the WR
13.3 Commentson Observed Spectra 70 Classes WN, WC and WO 91