Eta Carinae and the Supernova Impostors

334 Pages·2012·7.175 MB·English

by  Roberta M. Humphreys, John C. Martin (auth.), Kris Davidson, Roberta M. Humphreys (eds.)

Eta Carinae and the Supernova Impostors
Astrophysics and Space Science Library
EDITORIALBOARD
Chairman
W.B.BURTON,NationalRadioAstronomyObservatory,Charlottesville,Virginia,U.S.A.
([email protected]);UniversityofLeiden,TheNetherlands
([email protected])
F.BERTOLA,UniversityofPadua,Italy
J.P.CASSINELLI,UniversityofWisconsin,Madison,U.S.A.
C.J.CESARSKY,CommissionforAtomicEnergy,Saclay,France
P.EHRENFREUND,LeidenUniversity,TheNetherlands
O.ENGVOLD,UniversityofOslo,Norway
A.HECK,StrasbourgAstronomicalObservatory,France
E.P.J.VANDENHEUVEL,UniversityofAmsterdam,TheNetherlands
V.M.KASPI,McGillUniversity,Montreal,Canada
J.M.E.KUIJPERS,UniversityofNijmegen,TheNetherlands
H.VANDERLAAN,UniversityofUtrecht,TheNetherlands
P.G.MURDIN,InstituteofAstronomy,Cambridge,UK
F.PACINI,IstitutoAstronomiaArcetri,Firenze,Italy
V.RADHAKRISHNAN,RamanResearchInstitute,Bangalore,India
B.V.SOMOV,AstronomicalInstitute,MoscowStateUniversity,Russia
R.A.SUNYAEV,SpaceResearchInstitute,Moscow,Russia
Forfurthervolumes:
http://www.springer.com/series/5664
Kris Davidson • Roberta M. Humphreys
Editors
Eta Carinae and the
Supernova Impostors
123
Editors
KrisDavidson RobertaM.Humphreys
MinnesotaInstituteforAstrophysics MinnesotaInstituteforAstrophysics
UniversityofMinnesota UniversityofMinnesota
116ChurchStreetSE 116ChurchStreetSE
Minneapolis,MN55455 Minneapolis,MN55455
USA USA
ISSN0067-0057
ISBN978-1-4614-2274-7 e-ISBN978-1-4614-2275-4
DOI10.1007/978-1-4614-2275-4
SpringerNewYorkDordrechtHeidelbergLondon
LibraryofCongressControlNumber:2012930990
©SpringerScience+BusinessMedia,LLC2012
Allrightsreserved.Thisworkmaynotbetranslatedorcopiedinwholeorinpartwithoutthewritten
permission of the publisher (Springer Science+Business Media, LLC, 233 Spring Street, New York,
NY10013, USA),except forbrief excerpts inconnection with reviews orscholarly analysis. Usein
connectionwithanyformofinformationstorageandretrieval,electronicadaptation,computersoftware,
orbysimilarordissimilarmethodologynowknownorhereafterdevelopedisforbidden.
Theuseinthispublicationoftradenames,trademarks,servicemarks,andsimilarterms,eveniftheyare
notidentifiedassuch,isnottobetakenasanexpressionofopinionastowhetherornottheyaresubject
toproprietaryrights.
Coverillustration:Color-compositeimageoftheCarinaNebula,revealingexquisitedetails
inthestarsanddustinthenebula.EtaCarinaeisatthecenterwiththeKeyholeNebulajust
toitsright.NorthisupandEastistotheleft.Credit:ESO.
Printedonacid-freepaper
SpringerispartofSpringerScience+BusinessMedia(www.springer.com)
To theobservers oftheSouthernSky.

Preface
Eta Carinae is well knownto astronomersforits manysuperlatives.It is the most
massive, most luminous star in our region of the Milky Way. During its “Great
Eruption”170yearsagoitejected10M(cid:2)ormore,creatingitsfamousHomunculus
Nebula. We now know that its Great Eruption was the energetic, non-terminal
explosion of a very massive star nearing the end of its short life. But ηCar and
itsGreatEruptionmaynotbeunique,someweirdevent,onlyobservedonce.
In1965FritzZwickyproposedaclassofsupernovaeventshecalled“TypeV”,
relativelyfaintatmaximumwithlongdurations.Therewereonlytwomembersof
hisType V group,ηCar andSN1961v.These stars were nottrue supernovaeand
today we recognize several stars that had giant eruptions in which they increase
theirtotalluminosityandbecomebrightenoughtobemistakenforunderluminous
supernovae. In addition to η Car, examples include SN1961v, SN1954j, P Cyg
400 years ago, V1 in N2363 and probably the “Pistol star” near the Galactic
Center. The modern supernova surveys are producing a growing list of sub-
luminous outbursts from objects in other galaxies. These “supernova impostors”
areapparentlyverymassivestars undergoingeruptionssimilar to ηCar andother
unstablestarssuchastheLuminousBlueVariables(LBVs).Hencethetitleofthis
book.Thesestarsareveryrare,however,andmosthavebeenobservedonlysparsely.
The most massive stars are at the intersection of several critical areas of
modern astrophysics including the chemical evolution of galaxies via their high
mass loss episodes, as the likely progenitorsof gamma-raybursters and the most
luminous supernovae, and as candidates for the “first stars” in the Universe.
Extremely luminous supernovae, like SN2006gy, may be the terminal explosions
ofverymassivestarssurroundedbyextensivecircumstellarmaterialfromprevious
eruptions.TheroleofhighmasslosseventslikethatofηCaronthepre-supernova
stateofthesestarsisclearlyofincreasinginterestinastrophysics.
Our understanding of this remarkable object has benefited from the work
and insight of numerous astronomers over the past century many of whom are
now deceased. Due to the limitations on the size of this volume, it was not
possible to invite all current researchers for a contribution. The editors therefore
gratefullyacknowledgethecontributionsofPatriciaWhitelockandMichaelFeast,
vii
viii Preface
ChrisSterken andAntoninVanGenderen,RobertoViotti, AugustoDamineli,Ted
Gull,JohnMeaburn,OtmarStahl,NoamSoker,andBobGehrz.
The contributed chapters in this volume provide a comprehensive review of η
Car, including its Great Eruption, historical evolution and recovery, its wind and
ejecta and its relation to other very massive unstable stars, the origin of their
instabilities and eventual fate. The contributions are written by experts in their
fields and hence are intended for professional astronomers, graduate students in
astrophysics,andphysicistsinterestedinthefinalstagesofstellarevolution.These
reviews are based on the most recent observations from space and ground-based
telescopes and the currentstate of our theoreticalunderstanding,nevertheless, we
mustemphasizethatηCarneverceasestosurpriseus.
Minneapolis,MN KrisDavidson
RobertaM.Humphreys
Contents
1 EtaCarinae:From1600tothePresent .................................. 1
RobertaM.HumphreysandJohnC.Martin
2 TheCompanyEtaCarinaeKeeps:StellarandInterstellar
ContentoftheCarinaNebula............................................. 25
NolanR.Walborn
3 TheCentralStar:InstabilityandRecovery............................. 43
KrisDavidson
4 TheWindsofEtaCarinaeandOtherVeryLuminousStars.......... 67
Francisco(Paco)NajarroandD.JohnHillier
5 PhysicsoftheInnerEjecta ................................................ 95
FredHamann
6 High-Resolution Studies of Eta Carinae’s Ejecta
andStellarWind............................................................ 129
GerdWeigeltandStefanKraus
7 AllThingsHomunculus.................................................... 145
NathanSmith
8 TheOuterEjecta ........................................................... 171
KerstinWeis
9 X-rayVariabilityandtheSecondaryStar ............................... 195
M.F.CorcoranandK.Ishibashi
10 EtaCarinaeandtheLuminousBlueVariables ......................... 221
JorickS.Vink
11 TheSupernovaImpostors ................................................. 249
SchuylerD.VanDykandThomasMatheson
ix