The Interstellar Medium, Expanding Nebulae and Triggered Star Formation: Theory and Simulations

82 Pages·2016·2.176 MB·English

by  Thomas G. Bisbas (auth.)

SPRINGER BRIEFS IN ASTRONOMY
Thomas G. Bisbas
The Interstellar
Medium, Expanding
Nebulae and
Triggered Star
Formation
Theory and
Simulations
123
SpringerBriefs in Astronomy
SeriesEditors
MartinRatcliffe
ValleyCenter,Kansas,USA
WolfgangHillebrandt
MPIfürAstrophysik,Garching,Germany
MichaelInglis
LongIsland,NewYork,USA
DavidWeintraub
VanderbiltUniversity,Nashville,Tennessee,USA
Moreinformationaboutthisseriesathttp://www.springer.com/series/10090

Thomas G. Bisbas
The Interstellar Medium,
Expanding Nebulae and
Triggered Star Formation
Theory and Simulations
123
ThomasG.Bisbas
DepartmentofPhysicsandAstronomy
UniversityCollegeLondon
London,UK
ISSN2191-9100 ISSN2191-9119 (electronic)
SpringerBriefsinAstronomy
ISBN978-3-319-26140-9 ISBN978-3-319-26142-3 (eBook)
DOI10.1007/978-3-319-26142-3
LibraryofCongressControlNumber:2015955145
SpringerChamHeidelbergNewYorkDordrechtLondon
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sisterA(cid:7)(cid:7)˛ andmybrotherH(cid:10)(cid:3)˛&,andmy
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Preface
The book you hold serves as a handbook useful for graduate students and
astronomers in their early career who wish to have a quick introduction to the
concepts of the interstellar medium, nebulae, and triggered star formation. The
present work is neither a textbook nor an overview. The aim is to provide some
key work for the reader with the necessary updates in the field. At the same time
particular effort has been paid toward an outreach type of presentation for the
majorityofthetopicscovered.Followingthatwayofthinkingandinordertobring
the reader a step closer to the subject of nebulae, images taken from one of the
world’smosttalentedastronomyphotographers,KalliasIoannidis,havebeenused.
Thephotographsyouseeinthebookconsistafractionoftheastoundinggallerythat
KalliasIoannidisholds.Alloftheimagespresentedhavebeentakenfromvarious
parts in Greece including Grevena, Thessaloníki, Kavala, and the beautiful island
ofThassos.
The text is divided into four main chapters, while the fifth one summarizes
the entire book. The first chapter discusses the interstellar medium, its properties,
and its chemistry. The second chapter is dedicated to the characteristics and the
dynamicalevolutionofnebulae.Thethirdchapterdiscussestheconceptoftriggered
star formation, while the fourth one serves as short introduction to computational
astrophysicspresentingexamplesofexpandingnebulae.Thereadershouldbeaware
thatcomputationalastrophysicsisasubjectthatevolvesrapidly,andconsequently
theliteratureisupdatedextremelyfrequently(approximatelyonaweeklybasis).
AtthispointIwouldliketothankvariouscolleagueswithwhoIhadinteresting
discussionsformanyaspectsofthatbook.IwouldliketothankThomasHaworth,
Serena Viti, Padelis Papadopoulos, Mike Barlow, Jeremy Yates, Patrick Owen,
Jonathan Mackey, and Robin Williams. Special thanks go to my Ph.D. supervisor
AnthonyWhitworthwhowasthefirsttointroducemetocomputationalastrophysics
and also to my colleagues Richard Wünsch, Jan Palouš, Stefanie Walch, David
Hubber,DimitrisStamatellos,andJimDale.Thanksalsogotovariousotherpeople:
vii
viii Preface
DimitraStrongylou,PanagiotisKotsios,ElenaBacharopoulou,AretiMalkogianni,
AntiNalmpanti,ChristophorosTsantoulas,AntoniosMakrymallis,VasileiaFilidou,
AngelosTsiaras,DimitrisandMariaMiroti,KostasTziotziou,DionisisChandolias,
LazarosVoulgaris,MariaCvorkov,andGiannisOrkopoulos.
My deepest thanks go to my parents George and Xanthi, my siblings Anna
and Elias, my grandparents Elias and Elli, and to Panos for their love and support
throughoutmyentirecareer.Withoutthemthisbookwouldnothavebeenpossible.
London,UK ThomasG.Bisbas
September2015
Contents
1 TheInterstellarMedium .................................................... 1
1.1 Overview ................................................................. 1
1.2 TheDustyISM........................................................... 5
1.3 InterstellarRadiationField .............................................. 8
1.4 PhotodissociationRegions............................................... 8
1.5 CosmicRays ............................................................. 11
1.6 DetectionofH2........................................................... 13
1.7 LifeCycleoftheStarsandtheISM..................................... 14
References...................................................................... 15
2 Nebulae ........................................................................ 17
2.1 IonizationandRecombinationofHydrogen............................ 17
2.2 CategoriesofNebulae ................................................... 19
2.2.1 Diffuse(Emission)Nebulae..................................... 20
2.2.2 PlanetaryNebulae ............................................... 21
2.2.3 SupernovaRemnants ............................................ 22
2.2.4 ReflectionandDarkNebulae.................................... 23
2.3 PhotoionizationEquilibrium ............................................ 24
2.4 HeatingandCoolingMechanisms ...................................... 27
2.5 R-TypeExpansion ....................................................... 28
2.6 D-TypeExpansion ....................................................... 29
2.6.1 FurtherDiscussion............................................... 32
References...................................................................... 34
3 TriggeredStarFormation ................................................... 35
3.1 Overview ................................................................. 35
3.2 GravitationalCollapse................................................... 38
3.3 InstabilitiesDuringtheD-TypePhase .................................. 40
3.3.1 VishniacInstability .............................................. 40
3.3.2 Rayleigh-TaylorInstability...................................... 42
3.4 CollectandCollapse..................................................... 44
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