Chemical and physical properties of the OH, CN and C2 jets in Comet Hale Bopp (1995 O1)

171 Pages·2000·6.8 MB·English

by  Lederer, Susan Maria

THECHEMICALANDPHYSICALPROPERTIES
OCFOTMHEETOHH,ALCEN-BAONPDPC(219J9E5T0S1)IN
By
SUSANMARIALEDERER
ADISSERTATIONPRESENTEDTOTHEGRADUATESCHOOL
OFTHEUNIVERSITYOFFLORIDAINPARTIALFULFILLMENT
OFTHEREQUIREMENTSFORTHEDEGREEOF
DOCTOROFPHILOSOPHY
UNIVERSITYOFFLORIDA
2000
Copyright2000
hv
SusanMariaLederer
Thisisdedicatedtomyfamily,whohassupportedmeduringeverystepof
myeducationandmylife.
ACKNOWLEDGEMENTS
MysincerestthanksgotoDr. HumbertoCampinswhoagreedtoadviseme
evenwhenhisschedulewasquitefull,andwhocontinuedhisroleasmyadvisorlong
afterhiscommitmentstoUFhadpassed. Hetaughtmetothinkasanindependent
scientist, yet guided me and encouraged me through the difficult times. He has
remainedanactive,committedadvisorinmyresearch, andhisguidancehasbeen
invaluable. IwouldalsoliketothankDrs. DavidSchleicher, DavidOsip, Michael
A'Hearn,andStephenLarsonfortheirguidanceinobservationalastronomy,cometary
science, andmyresearchproject. Myresearchwouldnothaveprogressedwithout
theinputofallthesepeople.
Iwouldliketothankmycommitteemembers,Drs. ElizabethLada,Richard
Elston, StanleyDermott, andMartinVala. IparticularlythankDr. Ladaforher
helpasmypseudo-advisorinDr. Campin'sabsence,Dr. Valawhoagreedtositon
mycommitteeonlymonthsbeforemyfinaldefense,andDr. JonathanWilliamswho
agreedtositinonmydefenseforDr. Ladawithlessthanaweek'snotice.
IwouldalsoliketothankDr. CaseyLissewhowasalwayswillingtodiscuss
myresearch, andwhospentmanyhoursfillingmythesiswithredinktoimprove
itscontents. IwishtothankDrs. AmyLovellandNalinSamarasinhaforhelpful
discussionsandtheirwillingnesstosharepiecesoftheirMonteCarlocodes. Ialso
thankJeffJulianforhisamazingabilitytocreate3Dfigures,andforhiswillingness
tohelpinanywayatamoment'snotice. Dr. LarryWasserman(LowellObservatory)
alsodeservescreditforhelpingmesolvenever-before-seenproblemswhileobserving
at 3 a.m. I alsothank him forsharinghis ephemerides program and alteringit
togenerateadditionalinformationthatwascrucialtomyMonteCarloroutines. I
IV
wouldalsoliketoexpressmyappreciationforAmyNewberry, whoseexpertisein
theEnglishlanguagehelpedimprovenotonlythegrammar,butalsocutdownthe
infinitenumberofcommasscatteredthroughthisthesis.
Any acknowledgement would be incomplete without mention ofall ofthe
peopleat the University ofFlorida. Thanks tothededication ofouroffice staff,
includingGlenda,Ann,AudreyandDebra-Iwasalwaysregisteredforclasseson
time,wasalwayspaid,andwasabletotraveltodistantlands(andnot-so-distant
lands). Myofficemates,Scott,James,Jim,andElisha,madethelonghoursinthe
spacesciencesbuildingenjoyablewithenlighteningconversationsrangingfromGator
footballtothepossibilityoflifeexistingintheuniverse,andeverythinginbetween.
Icannotbegintolistallthefriendswhohavegivenmesupportthroughout
thisthesis. I amverygratefulforDavid, Teresa, Alexesand KrystinaCiardifor
makingmepartoftheirfamily,alwayskeepingthedooropenforme, andfeeding
memanyhealthymealsthroughoutthelasttwoyears. IthankJoannaLevinefor
manystress-relievingmochabreaks. Iamalsoindebtedtothemanyfriendswho
havecontinuouslyencouragedmefromafar,includingBobThompson,SeanPowell,
SheilaSnow,JamieBallard,andMelissaBenedict. Thislistwouldnotbecomplete
withoutmentioningBarbColba(myfavoriteteacher),whotaughtmethatlearning
wasfunandschoolwascoolattheripeoldageof5,andcontinuestosupportme
fromafareventoday.
Iamdeeplygratefulformyextendedfamilywhosupportedmethroughout
myentireeducation. Ithankmyfather, Ken,andmother, Kath (whosespiritwill
alwaysbewithme),forencouragingmetolearnfromchildhoodthroughgraduate
school. Theywillalwaysbeclosefriendsaswellasparents. Iparticularlythankmy
dadforencouragingmetofollowmyinsatiablecuriosityaboutthephysicalworld
and heavens andentertheworldofresearch. Heknew Iwould be happiest in a
professionwherelearningneverends. Mymomtaughtmethatexcellingtobeyour
best is always the most rewarding, despite peer pressure. She was always there
withacomfortinghugorsmile,despitethedifficulties. Ithankmysister,Jennifer,
forplayingtheroleofconfidant,ineveryrespect,throughoutmylifeandoftenafter
midnight;mybrother,Matthew,forchallengingmetothinkandgrow;andmysister,
Katie,forheropennessinlifeandherenvelopinghugs. Iwouldalsoliketothank
LouforshowingmesupportwhenIbarelyknewhim,andforemanatingapassion
forlifethathasinfluencedusall. IalsowishtoexpressmygratitudetomyActive
family,Karin,Dave,Katie,Ben,andMeghanOlson,whohasbeenmysecondfamily
throughoutmyentirelife. Ialsowishtothankmyparents; grandparents, Walter
SchneiderandMaryLederer;andmyauntanduncle,RuthandDeanTwedt-their
generosityandsupportallowedmetogainthefullesteducationpossible. Without
them,I'msuremyeducationalendevourswouldhavelastedyearslonger. Finally,I
wishtothankDavidSchwenkforhisinfinitepatiencethroughoutthefinalstagesof
mydissertation;forhissupportofmyworkandmylife;andforhisinfectioussmile,
energy,andlove. Thesearethepeoplewhohelpedmemaintainmysanityanddrive,
andtowhomIwillalwaysbeindebted.
VI
TABLEOFCONTENTS
ACKNOWLEDGEMENTS iv
LISTOFTABLES ix
LISTOFFIGURES x
ABSTRACT xii
CHAPTERS
1 INTRODUCTION 1
1.1 TheOortCloudandKuiperBelt 5
1.2 PropertiesoftheComa 5
1.2.1 CometaryJets 6
1.2.2 CometHale-Bopp 8
1.2.3 OHasaTracerofH2 10
1.2.4 JetSource: GasorGrain? 12
1.3 Synopsis 14
2 OBSERVATIONSANDDATAREDUCTION 15
2.1 FacilitiesandInstrumentation 15
2.2 DataReduction 16
2.2.1 InitialDataReduction 16
2.2.2 AbsoluteCalibration 23
2.2.3 ImageProcessingandEnhancementRoutines 25
2.3 ProjectedExpansionVelocities 26
2.4 Summary 30
3 MONTECARLOMODELING 31
3.1 Introduction 31
3.1.1 HaserModel 32
3.1.2 VectorialModel 32
3.1.3 HydrodynamicModels 33
3.1.4 MonteCarloModel 34
3.2 MonteCarloModelsDevelopedforThisWork 34
3.2.1 GasSourceVersusGrainSource 35
3.2.2 Non-collisionalIsotropicModel 36
3.2.3 Collisions 40
3.2.4 CollisionalJetModels 47
vn
3.3 Summary 50
4 ANALYSISANDDISCUSSION 53
4.1 Introduction 53
4.2 DataAnalysis 54
4.2.1 JetIdentification 54
4.2.2 ComparingtheMorphologyofOH,CN,andC2 62
4.2.3 JetWidths 67
4.2.4 EvolutionoftheJetswithTime 68
4.3 MonteCarloModelAnalysis 70
4.3.1 GasversusCHONGrainSource 73
4.3.2 InitialParentVelocityandAlphaParameter 83
4.3.3 RangeofInitialParentVelocities 86
4.3.4 DaughterVelocity 86
4.3.5 LifetimesofParentandDaughter 89
4.3.6 RadiationPressure 94
44..33..87 NPhuamsbeerAngalned,PPoAsistuino,nSsuonf'sthCeomAcettiovceenAtrreiacsLocation.... 9948
4.3.9 OpeningAngleoftheActiveAreas 101
4.3.10 StrengthoftheJetsandSolarInsolation 102
4.4 Results 103
4.4.1 ExpansionVelocitiesandJetWidths 103
44..44..23 PJertojSeocutrecde:LoGcaastivosnsGrofaiAnctiveAreasontheNucleus . . . 111067
4.5 Discussion 129
4.5.1 Morphology 129
4.5.2 EffectonProductionRates 132
4.5.3 Compositionofthenucleusandextendedsource 133
4.5.4 ImplicationsfortheHeterogeneityoftheNucleus 134
4.6 Summary 136
5 CONCLUSIONS 137
5.1 Introduction 137
5.2 NewResults 138
5.3 DirectionsforFutureWork 140
APPENDIXES
A DUSTPRODUCTION(A/p) 143
B THEHASERMODEL 145
REFERENCES 147
BIOGRAPHICALSKETCH 155
Vlll
LISTOFTABLES
1-1 Branchingratiosofwater 11
2-1 Narrowbandfiltercharacteristics 17
2-2 CometHale-Boppobservingdetails 17
3-1 MonteCarlomodelparameterspace 38
3-2 Collisionalcrosssections 46
4-1 Species-dependentmodelinputparameters 72
4-2 Modelinputparameters 72
4-3 Projectedexpansionvelocities 104
4-4 Projectedjetwidths 107
4-5 Locationsofmodelactiveareas 109
4-6 Hasermodelproductionrates 134
IX
LISTOFFIGURES
2-1 Marchtimesequence 28
3-1 MonteCarlomodel: Collisionalandnon-collisionalmodels 48
3-2 Radialprofilesofdataandbest-fitmodels(April26,1997) 51
4-1 OH,CN,andC2data(March6,1997) 55
4-2 OH,CN,andC2data(April26,1997) 56
4-3 OHdatawithvariousimageprocessingtechniquesapplied 58
4-4 CNdatawithvariousimageprocessingtechniquesapplied 59
4-5 C2datawithvariousimageprocessingtechniquesapplied 60
4-6 Continuumdatawithvariousimageprocessingtechniquesapplied . . 61
4-7 Gasimagesbeforeandaftercontinuumcorrection(March6,1997) . . 63
4-8 Gasimagesbeforeandaftercontinuumcorrection(April26,1997) . . 64
4-9 CNcontinuumcontaminationanalysis 66
4-10 Radialprofileofjets 69
4-11 OHdataandmodelswithgasandtriangularCHONgrainjetsources 74
4-12 CNdataandmodelswithgasandtriangularCHONgrainjetsources 75
4-13 C2dataandmodelswithgasandtriangularCHONgrainjetsource . 76
4-14 Radialprofilesofthedataandbest-fitmodelsforallgasspecies ... 77
4-15 RadialprofilesofOHdataandmodelsinthesunwarddirection ... 78
4-16 RadialprofilesofOHdataandmodelsintheanti-sunwarddirection . 79
4-17 RadialprofilesofCNdataandmodelsinthesunwarddirection ... 80
x