Exploring the Architecture of Transiting Exoplanetary Systems with High-Precision Photometry

170 Pages·2018·11.279 MB·English

by  Kento Masuda

Springer Theses
Recognizing Outstanding Ph.D. Research
Kento Masuda

Exploring the
Architecture
of Transiting
Exoplanetary Systems
with High-Precision
Photometry
Springer Theses
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Kento Masuda
Exploring the Architecture
of Transiting Exoplanetary
Systems with High-Precision
Photometry
Doctoral Thesis accepted by
the University of Tokyo, Tokyo, Japan
123
Author Supervisor
Dr. KentoMasuda Prof. YasushiSuto
Department ofAstrophysical Sciences Department ofPhysics
Princeton University TheUniversity of Tokyo
Princeton, NJ Tokyo
USA Japan
ISSN 2190-5053 ISSN 2190-5061 (electronic)
SpringerTheses
ISBN978-981-10-8452-2 ISBN978-981-10-8453-9 (eBook)
https://doi.org/10.1007/978-981-10-8453-9
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’
Supervisor s Foreword
SincethefirstdiscoveryofanexoplanetorbitingaroundaSun-likestar,exoplanets
havebeenestablishedasoneofthemostfascinatingresearchareasinastronomy.In
particular, the Kepler mission has told us numerous surprising diversities of exo-
planetary systems, which are supposed to provide a variety of key clues to their
origin and evolution over the cosmological timescales.
In this thesis, the author presents several different approaches to the problem.
AfterabriefoverviewoftheobserveddiversityofexoplanetarysystemsinChap.1,
he reviews the observational methodology to determine the obliquity of host stars
anddescribespossiblechannelstospin–orbitmisalignmentinChaps.2and3.The
following chapters correspond to his original published results: first determination
ofthetrue(notprojected)spin–orbitangleforthetransitingmulti-planetarysystem
of a main-sequence host star, Kepler-25, and that for HAT-P-7 from a combined
analysis of asteroseismology, transit photometry, and the Rossiter–McLaughlin
effect(Chap.4).Hewasabletoderivebeautifullythespin–orbitmisalignmentsfor
Kepler-13AbandHAT-P-7bfromtheprecisemodelingofgravitydarkeningeffect
(Chap. 5). Finally, he successfully determined the architecture of the hierarchical
triple system KIC 6543674 from the Kepler photometry alone (Chap. 6).
The methodologies that he described in each chapter will find broader applica-
tions in future data, and promise to provide fundamental contribution to under-
standing formation and evolution of exoplanetary systems.
I am confident that this book serves as a good introduction for readers who are
interested in accurate modeling and characterization of exoplanetary systems.
Tokyo, Japan Yasushi Suto
January 2018
v
Parts of this thesis have been published in the following journal articles:
Chapter 4—Benomar, O., Masuda, K., Shibahashi, H., Suto, Y. “Determination of
three-dimensional spin–orbit angle with joint analysis of asteroseismology, transit
lightcurve,andtheRossiter–McLaughlineffect:CasesofHAT-P-7andKepler-25,”
PublicationsoftheAstronomicalSocietyofJapan,66(2014)94(21pp.)Published
by Oxford University Press on behalf of the Astronomical Society of Japan.
Chapter 5—Masuda, K. “Spin–Orbit Angles of Kepler-13Ab and HAT-P-7b from
Gravity-darkenedTransitLightCurves,”TheAstrophysicalJournal,805(2015)28
(14pp.) Published by IOP Publishing for the American Astronomical Society.
Chapter6—Masuda,K.,Uehara,S.,Kawahara,H.“AbsoluteDimensionsofaFlat
Hierarchical Triple System KIC 6543674 from the Kepler Photometry,” The
AstrophysicalJournalLetters,806(2015)L37(7pp.)PublishedbyIOPPublishing
for the American Astronomical Society.
vii
Acknowledgements
Iwouldliketoexpressmydeepestgratitudetomysupervisor,YasushiSuto,forhis
continuous encouragement, inspiring discussions, and many insightful comments
on my works. I feel very fortunate that I had him as my supervisor, who gave me
many opportunities to broaden the possibilities for myself, always encouraged me
to pursue any topic I fancy, and sincerely listened to my ideas still in their very
vagueforms.Aboveallelse,Ilearnedfromhisopen-mindednessandhisattitudeto
think on his own to understand something.
Chapter 4 of this thesis is a collaboration work with Othman Benomar and
HiromotoShibahashi. Not only were they good teachersof asteroseismology, they
were also very supportive collaborators, who gave me a marvelous opportunity to
learn how the good collaboration works. Even after the completion of that work,
theykeeplettingmeknowofstimulatingresearchtopicsintherelatedfields,which
I appreciate very much.
InChap.6,IwasfortunateenoughtohaveanopportunitytoworkwithHajime
Kawahara and Sho Uehara. I enjoyed this work from start to finish, and whole-
heartedly thank them for always stimulating conversations over a lot of coffee.
Indeed, the work with them helped me to extend my research to the field I would
haveneverimaginedtoworkonotherwise.Theexperiencealsomademefeelsure
thattheinteractionbetweendiversepersonalitiesisanessentialpartoftheresearch.
I am also grateful to Takayuki Kotani and Shin’ya Yamada, for sharing cheerful
experience of observations as a part of the FLEX (Fuchinobe Lightcurve
EXploration) collaboration.
I would like to thank (ex-)members of the exoplanet group at UTAP (The
UniversityofTokyoTheoreticalAstrophysicsgroup),YukaFujii,TeruyukiHirano,
YuxinXue,ShoyaKamiaka,andMasatakaAizawa.IfeelfortunatethatIwasable
to have them as good examples when I joined the group, and am thankful to them
for sharing the seminars that motivated me to study exoplanets. I am particularly
gratefultoTeruyukiHirano, whofirstintroduced theKeplerdata tomeandtaught
methebasic ways ofanalyzingthem.Iowe it much tohim thatIwas able tostart
my own research rather smoothly.
ix
x Acknowledgements
I would also like to thank all the other members of UTAP and RESCEU
(ResearchCenterfortheEarlyUniverse)forawonderfulenvironmentwhereIhad
an enjoyable graduate student life. In particular, I would like to offer my special
thanks to Masamune Oguri, Gen Chiaki, and Natsuki H. Hayatsu, with whom I
spentafuntimeovercoffee,etc.Iwouldliketoexpressmyrespectfortheirefforts
to make UTAP a better environment.
MysincerethanksalsogotoJoshuaN.WinnandhisgroupattheMassachusetts
Institute of Technology, where a part of this thesis was completed, for their hos-
pitality and helpful conversations. In completing this thesis, I was also helped by
the members of my thesis committee, Profs. Takao Nakagawa, Masahiro Ikoma,
MasahiroTakada,SyngeTodo,SatoshiYamamoto,andNorikoY.Yamasaki,who
gave me many constructive comments that remind me of what I need to bear in
mind in my future research. I do appreciate their encouragement and support.
Lastbutnotleast,Iwouldliketoexpressmydeepappreciationtomyparentsfor
supporting me to study at graduate school, and to my spouse, Misa, for her gen-
erosity and patience.
ThisthesisincludesdatacollectedbytheKeplermission.FundingfortheKepler
missionisprovidedbytheNationalAeronauticsandSpaceAdministration(NASA)
ScienceMissionDirectorate.IamgratefultotheentireKeplerteamformakingthe
revolutionarydataavailable.Someofthedatapresentedinthisthesiswereobtained
fromtheMikulskiArchiveforSpaceTelescopes(MAST).STScIisoperatedbythe
AssociationofUniversitiesforResearchinAstronomy,Inc.,underNASAcontract
NAS5-26555. Support for MAST for non-HST data is provided by the NASA
OfficeofSpaceScienceviagrantNNX09AF08Gandbyothergrantsandcontracts.
We are also grateful toSimon Albrecht and Joshua N.Winn for providing us with
the radial velocity data of Kepler-25 analyzed in Chap. 4.
ThisthesishasmadeuseoftheNASAExoplanetArchive,whichisoperatedby
the California Institute of Technology, under contract with NASA under the
ExoplanetExplorationProgram.ThisthesishasmadeuseofNASA’sAstrophysics
Data System Bibliographic Services as well. The data analysis was in part carried
out on the common use data analysis computer system at the Astronomy Data
Center, ADC, of the National Astronomical Observatory of Japan.
I gratefully acknowledge the support by Japan Society for the Promotion of
Science Research Fellowships for Young Scientists (No. 26-7182) and by the
Leading Graduate Course for Frontiers of Mathematical Sciences and Physics.
Contents
1 Diversity of the Extrasolar Worlds . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.1 The Overall Occurrence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.1.1 Hot Jupiters. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1.2 Super-Earths and Mini-Neptunes . . . . . . . . . . . . . . . . . . . 3
1.1.3 Cold and Warm Jupiters. . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.1.4 Eccentric Planets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.2 Planet Hunting in a Nutshell . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
1.2.1 Direct Imaging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
1.2.2 Radial Velocity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
1.2.3 Transit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
1.2.4 Microlensing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
1.2.5 Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
1.2.6 Other Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
1.3 Directions of Stellar Spin and Planetary Orbits. . . . . . . . . . . . . . . 15
1.3.1 Is the Obliquity Distribution a Simple Function?. . . . . . . . 16
1.4 Plan of This Thesis. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
2 Measurements of Stellar Obliquities . . . . . . . . . . . . . . . . . . . . . . . . . 21
2.1 Definition and Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
2.2 Obliquity from Spectroscopic Transit. . . . . . . . . . . . . . . . . . . . . . 22
2.2.1 The Rossiter-McLaughlin Effect . . . . . . . . . . . . . . . . . . . . 22
2.2.2 Doppler Tomography. . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
2.3 Obliquity from High-Precision Photometry. . . . . . . . . . . . . . . . . . 25
2.3.1 Asteroseismology. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
2.3.2 Gravity Darkening. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
2.3.3 Spectroscopic vsin i★ and Stellar Rotation Period . . . . . . . 28
2.3.4 Spot Anomaly. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
2.3.5 Spot-Modulation Amplitude . . . . . . . . . . . . . . . . . . . . . . . 29
xi