Planets, Stars and Stellar Systems: Volume 5: Galactic Structure and Stellar Populations

1140 Pages·2013·40.95 MB·English

by  Prof. Rosemary F. G. Wyse (auth.)

Terry D. Oswalt
Editor-in-Chief
Gerard Gilmore
Volume Editor

Planets, Stars and
Stellar Systems
volume 5
Galactic Structure and
Stellar Populations
Planets,StarsandStellarSystems
GalacticStructureandStellarPopulations

TerryD. Oswalt(Editor-in-Chief)
GerardGilmore(VolumeEditor)
Planets, Stars and
Stellar Systems
Volume 5:
Galactic Structure and
Stellar Populations
With452Figuresand38Tables
Editor-in-Chief
TerryD.Oswalt
DepartmentofPhysics&SpaceSciences
FloridaInstituteofTechnology
UniversityBoulevard
Melbourne,FL,USA
VolumeEditor
GerardGilmore
InstituteofAstronomy
CambridgeUniversity,UK
ISBN978-94-007-5611-3 ISBN978-94-007-5612-0(eBook)
ISBN978-94-007-5613-7(printandelectronicbundle)
DOI10.1007/978-94-007-5612-0
Thistitleispartofasetwith
SetISBN978-90-481-8817-8
SetISBN978-90-481-8818-5(eBook)
SetISBN978-90-481-8852-9(printandelectronicbundle)
SpringerDordrechtHeidelbergNewYorkLondon
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Series Preface
Itismygreatpleasuretointroduce“Planets,Stars,andStellarSystems”(PSSS).Asa“Springer
Reference”,PSSSisintendedforgraduatestudentstoprofessionalsinastronomy,astrophysics
andplanetaryscience,butitwillalsobeusefultoscientistsinotherfieldswhoseresearchinter-
estsoverlapwithastronomy.Ouraimistocapturethespiritof21st centuryastronomy–an
empiricalphysicalsciencewhosealmostexplosiveprogressisenabledbynewinstrumentation,
observationaldiscoveries,guidedbytheoryandsimulation.
Each volume, edited by internationally recognized expert(s), introduces the reader to a
well-defined area within astronomy and can be used as a textor recommendedreading for
an advanced undergraduateor postgraduatecourse. Volume 1, edited by Ian McLean, is an
essentialprimeronthetoolsofanastronomer,i.e.,thetelescopes,instrumentationanddetec-
torsusedtoquerytheentireelectromagneticspectrum.Volume2,editedbyHowardBond,isa
compendiumofthetechniquesandanalysismethodsthatenabletheinterpretationofdatacol-
lectedwiththesetools.Volume3,co-editedbyLindaFrenchandPaulKalas,providesacrash
courseintherapidlyconvergingfieldsofstellar,solarsystemandextrasolarplanetaryscience.
Volume4,editedbyMartinBarstow,isoneofthemostcompletereferencesonstellarstructure
andevolutionavailabletoday.Volume5,editedbyGerardGilmore,bridgesthegapbetween
our understandingof stellarsystemsand populations seenin greatdetail within the Galaxy
andthoseseenindistantgalaxies.Volume6,editedbyBill Keel,nicelycapturesourcurrent
understandingoftheoriginandevolutionoflocalgalaxiestothelargescalestructureofthe
universe.
The chapters have been written by practicing professionals within the appropriate sub-
disciplines. Available in both traditional paper and electronic form, they include extensive
bibliographicandhyperlinkreferencestothecurrentliteraturethatwillhelpreaderstoacquirea
solidhistoricalandtechnicalfoundationinthatarea.Eachcanalsoserveasavaluablereference
foracourseorrefresherforpracticingprofessionalastronomers.Thosefamiliarwiththe“Stars
andStellarSystems”seriesfromseveraldecadesagowillrecognizesomeoftheinspirationfor
theapproachwehavetaken.
Verymanypeoplehavecontributedtothisproject.IwouldliketothankHarryBlomand
Sonja Guerts(Sonja Japengaatthetime)ofSpringer, whooriginally encouragedmetopur-
suethisprojectseveralyearsago.Special thankstoouroutstandingSpringer editorsRamon
Khanna(Astronomy)andLydiaMueller(MajorReferenceWorks)andtheirhard-workingedi-
torialteamJenniferCarlson,ElizabethFerrell,JuttaJaeger-Hamers,JuliaKoerting,andTamara
Schineller.Theircontinuousenthusiasm,friendlyproddingandunwaveringsupportmadethis
seriespossible.Needlesstosay(butI’msayingitanyway),itwasnotaneasytaskshepherding
aprojectthisbigthroughtocompletion!
Mostofall,ithasbeenaprivilegetoworkwitheachofthevolumeEditorslistedaboveand
over100contributingauthorsonthisproject.I’velearnedalotofastronomyfromthem,andI
hopeyouwill,too!
January2013 TerryD.Oswalt
GeneralEditor

Preface to Volume 5
Studies of Stellar Populations have developed over the half-century since the term became
popular,attheVaticanConferenceof1957,tobecomethecriticalmethodologyforprecision
studiesoftheevolutionofstarformationwithtimeandlocation,galaxyassembly,theevolu-
tionofthechemicalelementsandtheirreturntotheinter-Galacticmedium,andthespatial
distributionofdarkmatter.NoneofthoseapplicationswasstronglyrepresentedintheVatican
Conferenceaswediscussthemtoday–ratherStellarPopulations andGalacticStructureisa
modern,vibrant,andfast-changing subject,building onthosebig questions whichmotivate
substantialaspectsofastronomytoday.
Thechaptersinthisvolumeshowboththehistoryofthediscoveriesandtheevolutionin
complexityofthesubject,frominitialconcernverylargelywithobservationallybaseddeter-
minations ofthethree-dimensional spatialandkinematicdistributions of thevarious stellar
populations,definedbystellartype,andtheinter-stellarmedium.Followingthatgroundwork,
itisperhapsourrealizationthatthe inter-stellarandthe intergalacticmediumhold mostof
theUniverse’sbaryons,andmuchcomplexchemistry,thathavecontributedimmenselytoward
recent understanding – the context of galaxies as “Island Universes” remains a surprisingly
gooddescriptorofobservations;yetweknowallstructuresintheUniverseliveinabroader
cosmologicalcontext.
Naturally, newly enabled technologies, especially in high-energy studies, and in high
spatialresolutionimaging/kinematicstudiesofbothstarsandgas,havenoearlycounterpart.
Theseveral chapters in this volume describing the extension of our knowledge beyond the
optical andlow-resolutionHI21-cmradiostudieshighlightimpressiveprogress,illustrating
aparadigmshiftinourGalacticview.
Thehighintrinsicinterestinunderstandingtheimplicationsofkinematicsformassdeter-
minationsandforGalaxyevolutionhasbeenanactivefieldthroughoutthetwentiethcentury,
asisstillthecase,andmeritsextensivediscussion.Thechapteron“HistoryofDarkMatterin
Galaxies”presentsthediscoveryofourcurrentconceptofDarkMatterremindsusthatsome
radicaldiscoveriesmatureonlyslowlyintoourconsciousness,othersleapforthfullyformed.
Stellarchemicalabundancedeterminationandinterpretationisnowamajorscience,with
quantitative high-resolutionspectroscopyonlargetelescopesdriving impressiveprogress.In
consequence,thisfeaturesverylargelyinthepresentvolume,representingitscritical rolein
modernastrophysics.Witharangeof5dexinmeasuredabundancesbeingavailableforanaly-
sis,wehavenowavailableaprobeoftheUniversefromtheveryearlieststarformationtothe
presentday.
ThestellarInitialMassFunctionwasasfundamentalandasmuchdebatedintheearliest
daysofthestudyoftheGalaxyasnow,withthechapterbyvanRhijn,writtenin1959,published
inthe1965volume,providingadirectlinktothepioneeringdaysofthesubject.Comparison
ofvanRhijn’sTable1withchapter4illustratestheimpressiveadvancesinastronomicaltech-
nology,data,andmodelingsophisticationthatahalf-centuryhasbought,whileremindingus
thatsomefundamentalquestionsremainopenfordebate.
Several chapters in the present volume develop the theme of determination of the
three-dimensionalstructureoftheMilkyWayGalaxy,achallengeinwhichsubstantialprogress
viii PrefacetoVolume5
has been made – especially through digital star count data in both optical and infrared
wavelengths–andwhereweanticipatearevolutionoverthenextdecadewiththeGaiamission.
Thisisanaturaltimetotakestockofwhathasbeenachievedwithground-basedopticaland
near-infraredimagingsurveys,thebeginningsoflargespectroscopicsurveys,thefirstgenera-
tionsofspace-basedthermal-infraredsurveys,superbmultiwavelengthcomplementarydata,
including both photon and particle messengers,and whena fundamental calibration of the
distancescale–thatholygrailofastrophysics–isfinallywithinsightinthecomingdecade.
GerardGilmore
UK
Editor-in-Chief
Dr.TerryD.Oswalt
DepartmentPhysics&SpaceSciences
FloridaInstituteofTechnology
150W.UniversityBoulevard
Melbourne,Florida32901
USA
E-mail:[email protected]
Dr.OswalthasbeenamemberoftheFloridaTechfacultysince1982andwasthefirstprofes-
sionalastronomerintheDepartmentofPhysicsandSpaceSciences.Heservesonanumberof
professionalsocietyandadvisorycommitteeseachyear.From1998to2000,Dr.Oswaltserved
asProgramDirectorforStellarAstronomyandAstrophysicsattheNationalScienceFounda-
tion.AfterreturningtoFloridaTechin2000,heservedasAssociateDeanforResearchforthe
CollegeofScience(2000–2005)andinterimViceProvostforResearch(2005–2006).Heisnow
HeadoftheDepartmentofPhysics&SpaceSciences.Dr.Oswalthaswrittenover200scientific
articlesandhaseditedthreeastronomybooks,inadditiontoservingasEditor-in-Chiefforthe
six-volumePlanets,Stars,andStellarSystemsseries.
Dr.OswaltisthefoundingchairmanoftheSoutheastAssociationforResearchinAstron-
omy(SARA), aconsortiumoftensoutheasternuniversitiesthatoperatesautomated1-meter
classtelescopesatKittPeakNationalObservatoryinArizonaandCerroTololoInteramerican
Observatory in Chile (see the website www.saraobservatory.org for details). These facilities,
which are remotelyaccessible on the Internet, are used for a variety of researchprojects by
facultyandstudents.TheyalsosupporttheSARAResearchExperiencesforUndergraduates
(REU)program,whichbringsstudentsfromallovertheU.S.eachsummertoparticipateone-
on-onewithSARAfacultymentorsinastronomicalresearchprojects.Inaddition,Dr.Oswalt
securedfundingforthe0.8-meterOrtegatelescopeontheFloridaTechcampus.Itisthelargest
researchtelescopeintheStateofFlorida.
Dr.Oswalt’sprimaryresearchfocusesonspectroscopicandphotometricinvestigationsof
verywidebinariesthatcontainknownorsuspectedwhitedwarfstars.Thesepairsofstars,whose
separationsaresolargethatorbital motionisundetectable,provideauniqueopportunityto
explorethelowluminosityendsofboththewhitedwarfcoolingtrackandthemainsequence;
totestcompetingmodelsofwhitedwarfspectralevolution;todeterminethespacemotions,
masses,andluminositiesforthelargestsinglesampleofwhitedwarfsknown;andtosetalower
limittotheageanddarkmattercontentoftheGalacticdisk.