Cataclysmic Cosmic Events and How to Observe Them

247 Pages·2008·5.17 MB·English

by  Martin Mobberley

Cataclysmic Cosmic Events
and How to Observe Them
Forothertitlespublishedinthisseries,goto
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Martin Mobberley
Cataclysmic Cosmic
Events and How to
Observe Them
1 3
MartinMobberley
Suffolk,UK
e mail: [email protected]
ISBN:9780387799452 eISBN:9780387799469
DOI:10.1007/9780387799469
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Acknowledgements
s
t
AswasthecasewithmyfivepreviousSpringerbooks,Iamindebtedtomyfellow n
e
amateurswhohavegenerouslydonatedpicturesofthemselves,andimagesoftheir m
results, to this project. I am especially indebted to Seiichiro Kiyota for his con- e
g
siderable help in contacting Japanese nova patrollers who donated images of d
themselves for Chapter 2. In addition, his countrymen Osamu Ohshima and e
l
Tomohisha Ohnokindlyassistedinobtaining photographsofthelegendarydis- w
o
covererMinoruHonda.InalphabeticalorderIwouldliketosincerelythankallof
n
thefollowingastronomerswithoutwhomthisbookwouldnothavebeenpossible: k
c
Ron Arbour, Mark Armstrong, Tom Boles, Denis Buczynski, John Fletcher, A
Katsumi Haseda, Guy Hurst, Ken Kennedy, Seiichiro Kiyota, Robin Leadbeater,
Gianluca Masi, Yuji Nakamura, Hideo Nishimura, Tomohisha Ohno, Osamu
Ohshima, Arto Oksanen, Gary and Jean Poyner, Yukio Sakurai, John Saxton,
Jeremy Shears, Mike Simonsen, Kesao Takamizawa, Akira Takao, Dave Tyler,
MauriValtonen,andMinoruWakuda.
Thanks also to the following organizations: the British Astronomical Associa-
tion (BAA), the European Space Agency (ESA), the National Aeronautics and
Space Administration (NASA), the Space Telescope Science Institute (STScI),
andtheSolarandHeliosphericObservatory(SOHO).
IwouldalsoliketothankallatSpringerwhohavemadethisbookpossible,in
particular,JennyWolkowicki,whohasconscientiouslyguidedthisbookandmy
previous three Springer books through the complex production process with an
essential injection of wry humor, despite being remorselessly ‘‘chased by alliga-
tors’’!WithoutJennynoneofthesebookswouldexist.
Finally,IamindebtedtomyfatherDenysMobberleyforhissupportinallmy
astronomicalactivitiesduringmypastfortyyearsinthishobby.
v
Contents
Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v
AbouttheAuthor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xi
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Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xiii e
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1. CataclysmicVariables. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
ABinarySystem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
StarsAlmostTouching. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
AccretionDisks,HotSpots,andEclipses . . . . . . . . . . . . . . . . . . . . 4
VariableStarNomenclature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
CategoriesofDwarfNovae. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
SuperoutburstsandSuperhumps . . . . . . . . . . . . . . . . . . . . . . . . . 10
Nova-likes,ZCams,andOthers . . . . . . . . . . . . . . . . . . . . . . . . . . 10
APeriod–LuminosityLink. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
MagneticCVs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
SymbioticStars. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
HowtoObserveCVs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
WorthwhileProjects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
SomeGoodDwarfNovaTargetsforCCDs . . . . . . . . . . . . . . . . . . . 33
LeadingCVObservers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
2. NovaeandRecurrentNovae. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
Novae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
AssociatedNebulosity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
MemorableNovae. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
RecurrentNovae. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
HowtoObserveNovaeandRecurrentNovae . . . . . . . . . . . . . . . . . 60
WheretoSearch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
SuccessfulPhotographicNovaHuntersandtheirEquipment . . . . . . 71
AvoidingFalseAlarms. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
PatrollingforNovaeOutsidetheMilkyWay. . . . . . . . . . . . . . . . . . 80
AndromedaandthePinwheel. . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
TheLMCandSMC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
ObtainingSpectraofNovae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
CheckingforRecurrentNovaOutbursts . . . . . . . . . . . . . . . . . . . . 87
RecurrentNovaeWorthMonitoring . . . . . . . . . . . . . . . . . . . . . . . 89
3. SolarFlares,GiantProminences,andFlareStars. . . . . . . . . . . . . . 99
SolarFlares . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99
Prominences. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
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The11-YearCycle. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102
MajorFlares. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103
HowtoObserveSolarFlaresandProminences. . . . . . . . . . . . . . . . 105
FlareStars . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112
4. BrightSupernovaeandHypernovae . . . . . . . . . . . . . . . . . . . . . . . 121
TypeIaSupernovae. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121
MassiveProgenitor/Core-CollapseSupernovae. . . . . . . . . . . . . . . . 122
SupernovaSubtypes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124
The‘Champagne’Supernova . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128
s TheBrightestSupernovae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128
t
n ExtraordinarySupernovae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129
e
t UltrabrightSupernovaeandHypernovae . . . . . . . . . . . . . . . . . . . . 133
n
o HowtoDiscoverandObserveSupernovae. . . . . . . . . . . . . . . . . . . 135
C
TheCompetitors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141
HardwareforPatrollers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146
SoftwareforPatrollers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146
CheckingSoftware. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147
AstrometricSoftware. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 148
5. ActiveGalaxies. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151
SupermassiveBlackHoles. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153
ConfusingClassifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156
Quasars . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157
Blazars,OVVs,andBLLacObjects . . . . . . . . . . . . . . . . . . . . . . . . 161
SeyfertGalaxies. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168
ActiveGalaxiesforObserving. . . . . . . . . . . . . . . . . . . . . . . . . . . . 174
6. GammaRayBursters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177
WhatCausesGRBs?. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 178
Short-DurationGRBs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179
SomeHistoricGRBs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 182
ANewGRBDetectionEra . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185
GRBsfromtheSWIFTEra . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185
HowtoObserveGRBs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187
NotableAmateurSuccessestoDate. . . . . . . . . . . . . . . . . . . . . . . . 189
FinalThoughts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195
7. HowtoDoVisualandCCDPhotometry . . . . . . . . . . . . . . . . . . . . 197
VisualPhotometry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197
TheRetina . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198
DarkAdaption . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198
EstimatingMagnitudesVisually . . . . . . . . . . . . . . . . . . . . . . . . . . 202
MagnitudeReporting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203
FractionalEstimates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203
PogsonStepEstimates. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204
JulianDate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204
Ergonomics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 205
CCDPhotometry. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 206
PhotometryinDetail . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 208
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ADifferentTypeofApertureandFWHM . . . . . . . . . . . . . . . . . . . 210
DarkFrames. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211
FlatFields . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213
UBVRI. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 215
CarryingOutPhotometry. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 217
Time-ResolvedPhotometry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 222
AIP’sMultipleImagePhotometry . . . . . . . . . . . . . . . . . . . . . . . . . 222
PeriodDeterminationTechniques. . . . . . . . . . . . . . . . . . . . . . . . . 225
Resources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 229
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Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 235 nt
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About the Author
MartinMobberleyisawell-knownBritishamateurastronomerwhoimagesawide
variety of objects, including comets, planets, novae, supernovae, and asteroids
(including 7239 Mobberley). He has written five previous amateur and practical
astronomybooksforSpringeraswellasthreechildren’sbooksaboutastronomy
and space travel. Martin has served as the British Astronomical Association’s
president and received the BAA’s Goodacre award in 2000. He is a regular
contributor to the British magazine Astronomy Now and the BBC Sky at Night
publicationandhasappearedasaguestonSirPatrickMoore’s‘‘SkyatNight’’TV
programonnumerousoccasionssincethelate1990s.
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xi
Preface
In the Victorian era – or for non-British readers, the mid-to-late nineteenth
century – amateur astronomy tended to center on Solar System objects. The
Moonandplanets,aswellasbrightcomets,werethekeyobjectsofinterest.The
brighter variable stars were monitored, but photography was in its infancy and
digitalimaginglayacenturyinthefuture.
Today,atthestartofthetwenty-firstcentury,amateursarebetterequippedthan
any professionals of the mid-twentieth century, let alone the nineteenth. An
amateur equipped with a 30-cm telescope and a CCD camera can easily image
objectsbelowmagnitude20and,fromverydarksites,22or23.Suchlimitswould
havebeenwithintherealmofthe100-and200-inchreflectorsonMountWilson
and Mount Palomar in the 1950s, but no other observatories. However, even
thosetelescopestookhourstoreachsuchlimits,andthenthephotographicplates
hadtobedeveloped,fixed,andexaminedbyeye.Inthemoderneradigitalimages
canbeobtainedinminutesandanalyzed‘onthefly’whilemoreimagesarebeing
downloaded. Developments can be e-mailed to other interested amateurs in real
time, during an observing session, so that when a cataclysmic event takes place
amateurs worldwide know about it. As recently as the 1980s, even professional
astronomerscouldonlydreamofsuchinstantaneouscommunicationandproces-
singability.
Thisnew-foundpowerinthehandsofbackyardobservershasenabledthemto
reachoutsidetheSolarSystem,andoutsideourowngalaxy,andpermittedthemto
monitorcolossaloutburstsandexplosionstakingplaceasfaroutastheedgeofthe
observable universe. Many of these events can only be described as cataclysmic
andinvolveviolentoutburstsofenergyrangingfrom1020to1047joules.Ajouleis
ameasureofenergyandawattisameasureofpower,thatis,awatt=ajouleper
second.Whendescribingextraordinarilyenergeticeventsitiscommontousethe
terms joules, or ergs, to describe the total amount of energy released in a single
event,whetherthateventisanovaorasupernova exploding,oramassivesolar
flare.Onejouleisequivalentto10millionergs.Anerghasbeencomparedtothe
amountofenergyneededbyamosquitotoachievetakeoff!A1-megatonhydro-
gen-bombgoingoffproducessomethinglike4(cid:2)1015joules.Thefamousvolcanic
explosionofKrakatoaisthoughttohaveproduced5(cid:2)1017joules.Butbeyond1020
jouleswestartmovingintodistinctlyastronomicalterritory.
Themildesteventsdiscussedinthisbookarethesolarflaresemittedbyourown
Sunthatrangeinenergyoutputfrom1020joules,forthebarelydetectableevents,
tothemostviolentflares,registeringbetween1025and1026joules.Flaresobserved e
c
on the nearest flare stars to our Solar System can routinely be of this order of a
f
magnitudeorgreater. e
r
Monitoring cataclysmic variable stars (CVs) has become an all-consuming P
hobby for many dedicated amateurs in the last few decades. Such binary stars
can flare dramatically in brightness by several 100-fold when in outburst, but
unlikenovaeorsupernovaetheycandoitalloveragainmonthslater.Inaddition
xiii