DOCSLIB.ORG

An Odyssey in Exoplanet Detection and Characterisation

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
An Odyssey in Exoplanet Detection and Characterisation thesis for the degree of licentiate of astronomy From Photons to Worlds Iskra Georgieva Division of Astronomy and Plasmaphysics Department of Space, Earth and Environment Chalmers University of Technology Gothenburg, Sweden, 2021 From Photons to Worlds Iskra Georgieva Copyright © 2021 Iskra Georgieva All rights reserved. Technical Report No. 2021-0064 ISSN 3.1415-9265 This thesis has been prepared using LATEX. Division of Astronomy and Plasma physics Department of Space, Earth and Environment Chalmers University of Technology SE-412 96 Gothenburg, Sweden Phone: +46 (0)31 772 1000 www.chalmers.se Printed by Chalmers Reproservice Gothenburg, Sweden, June 2021 Abstract Since the first unambiguous detection of a planet around a Sun-like, the in- terest in the new and exciting field of exoplanets has grown immensely. New and exciting developments are seen at a pace unparalleled for most subfields of astronomy and astrophysics. In this thesis, I describe the two most successful techniques for exoplanet detection and characterisation – transits and radial velocities – and the chal- lenges commonly encountered in extracting the planets from the data. Transit photometry allows us to measure the planet radius, while radial velocity measurements give us the planet’s minimum mass. These methods’ true strength, however, manifests in their combination as it allows us to esti- mate the true mass, which together with the radius gives us an estimate of a planet’s bulk density. This is a powerful quantity, which allows us to speculate about the structure and composition of a planet’s interior and atmosphere. I describe the process of detecting a planet in a stellar light curve, and how transits and radial velocities are modelled together in order to determine the planet parameters. I demonstrate how the ideal theoretical approach can be used to study a system in practice. However, the current challenges in exoplanet characterisation surpass the ideal case, leading us to explore more complex models. Finally, I show how by extending the ideal planet approach with non-parametric models, we can detect planets in complicated datasets, as demonstrated by the case of the TOI-1260 multi-planet system. Keywords: Exoplanet, planetary systems, transits, radial velocities. List of Publications This thesis is based on the following publications: [A] I. Y. Georgieva, C. M. Persson, O. Barragán, G. Nowak, M. Frid- lund, D. Locci, E. Palle, R. Luque, I. Carleo, D. Gandolfi, S. R. Kane, J. Korth, K. G. Stassun, J. Livingston, E. C. Matthews, K. A. Collins, S. B. Howell, L. M. Serrano, S. Albrecht, A. Bieryla, C. E. Brasseur, D. Ciardi, W. D. Cochran, K. D. Colon, I. J. M. Crossfield, Sz. Csizmadia, H. J. Deeg, M. Esposito, E. Furlan, T. Gan, E. Goffo, E. Gonzales, S. Grziwa, E. .W. Guen- ther, P. Guerra, T. Hirano, J. M. Jenkins, E. L. N. Jensen, P. Kabáth, E. Knudstrup, K. W. F. Lam, D. W. Latham, A. M. Levine, R. A. Mat- son, S. McDermott, H. L. M. Osborne, M. Paegert, S. N .Quinn, S. Red- field, G. R. Ricker, J. E. Schlieder, N. J. Scott, S. Seager, A. M. S. Smith, P. Tenenbaum, J. D. Twicken, R. Vanderspek, V. Van Eylen, J. N. Winn, “Hot planets around cool stars – two short-period mini-Neptunes transiting the late K-dwarf TOI-1260”. Accepted for publication in Monthly Notices of the Royal Astronomical Society. Other publications by the author, not included in this thesis, are: [B] R. Luque, ..., I. Georgieva, et al, “A planetary system with two transiting mini-Neptunes near the radius valley transition around the bright M dwarf TOI-776”. A&A, 2021, 645, 41. [C] M. Fridlund, ..., I. Georgieva, et al, “The TOI-763 system: sub-Neptunes orbiting a Sun-like star”. MNRAS, 2020, 498, 4503. [D] I. Carleo, ..., I. Georgieva, et al, “The Multiplanet System TOI-421 – a warm Neptune and a super puffy mini-Neptune transiting a G8 V star in a visual binary”. AJ, 2020, 160, 114 . [E] G. Nowak, ..., I. Georgieva, et al, “K2-280 b - a low density warm sub- Saturn around a mildly evolved star”. MNRAS, 2020, 497, 4423. [F] P. Bluhm, ..., I. Georgieva, et al, “Precise mass and radius of a transiting super-Earth planet orbiting the M dwarf TOI-1235: a planet in the radius gap?”. A&A, 2020, 639, 132. ii [G] J. Šubjak, ..., I. Georgieva, et al, “TOI-503: The First Known Brown- dwarf Am-star Binary from the TESS Mission”. AJ, 2020, 159, 151. [H] D. Hidalgo, ..., I. Georgieva, et al, “Three planets transiting the evolved star EPIC 249893012: a hot 8.8-M⊕ super-Earth and two warm 14.7 and 10.2-M⊕ sub-Neptunes”. A&A, 2020, 636, 89. [I] M.R. Díaz, ..., I. Georgieva, et al, “TOI-132 b: A short-period planet in the Neptune desert transiting a V = 11.3 G-type star”. MNRAS, 2020, 493, 973. [J] L.D. Nielsen, ..., I. Georgieva, et al, “Mass determinations of the three mini-Neptunes transiting TOI-125”. MNRAS, 2020, 492, 5399. [K] C.X. Huang, ..., I. Georgieva, et al, “TESS Spots a Hot Jupiter with an Inner Transiting Neptune”. ApJL, 2020, 892, 7. [L] K.W.F. Lam, ..., I. Georgieva, et al, “It Takes Two Planets in Resonance to Tango around K2-146”. ApJ, 2020, 159, 120. [M] C.M. Persson, ..., I. Georgieva, et al, “Greening of the brown-dwarf desert. EPIC 212036875b: a 51 MJ object in a 5-day orbit around an F7 V star”. A&A, 2019, 628, 64. iii Acknowledgments I would firstly like to thank my main supervisor Carina Persson and my co- supervisor Malcolm Fridlund for perhaps taking a leap of faith in hiring me instead of someone with a continuous background in the astrophysical sciences. I hope I am living up to your expectations. I am also grateful for your support in the sub-smooth experience that writing my first paper has been. I have undoubtedly learned a lot. I am especially thankful to OB for being as good a collaborator as he is a friend. I look forward to more adventures, both professional and casual. Finally, a massive thank you! to all my peeps here at AoP for helping to keep me sane during these difficult times – I hope to have contributed to any remaining sanity you have as well. iv Acronyms ARIEL: Atmospheric remote-sensing infrared exoplanet large sur- vey AU: Astronomical unit CHEOPS: Characterising exoplanet satellite CoRoT: Convection, rotation and planetary transits CCF: Cross-correlation function EB: Eclipsing binary ESPRESSO: Echelle spectrograph for rocky exoplanets and stable spec- troscopic observations EXPRES: Extreme precision spectrograph FOV: Field of view GP: Gaussian process HabEx: Habitable exoplanet observatory HARPS: High accuracy radial velocity planet searcher JWST: James Webb space telescope KST: Kepler space telescope LUVOIR: Large UV/Optical/Infrared surveyor MCMC: Markov chain Monte Carlo PLATO: Planetary transits and oscillations RV: Radial velocity TESS: Transiting exoplanet survey satellite v Definitions This section contains a non-exhaustive list of notation and constants in SI units commonly used throughout this work. The values are as per Prša et al. (2016). • M? – stellar mass • R? – stellar radius • Mp – planet mass • Rp – planet radius 30 • M – Solar mass, 1.988 × 10 kg 8 • R – Solar radius, 6.957 × 10 m 24 • M⊕ – Earth mass – 5.971 × 10 kg 6 • R⊕ – Earth radius – 6.3781 × 10 m 27 • MJ – Jupiter mass – 1.898 × 10 kg 7 • RJ – Jupiter radius – 7.1492 × 10 m • AU – Astronomical unit – 1.496 × 1011 m • pc – parsec – 3.086 × 1016 km vi Table 0.1: Basic stellar spectral classification. The values and ranges are as per Pecaut & Mamajek (2013) and are approximate. vii Contents Abstracti List of Papers ii Acknowledgements iv Acronymsv Definitions vi 1 Introduction1 1.1 What is an exoplanet? . .2 1.2 Exoplanet detection . .5 The transit method . .5 The radial velocity method . 11 1.3 Exoplanet demographics . 14 2 A closer look at the theory behind transits and radial velocities 17 2.1 Orbital elements . 17 2.2 Transit method . 18 Transit observables . 18 Other physical quantities . 21 ix Challenges and caveats . 23 2.3 Radial velocity method . 25 Combining the two methods . 26 Challenges . 27 3 From photons to worlds 31 3.1 Finding transits in light curve data . 31 3.2 Joint modelling of transits and RVs . 34 The harsh reality . 37 4 Paper summary 39 4.1 Paper A . 39 5 Outlook 43 5.1 Concluding remarks . 43 5.2 Reflection and Future work . 44 Bibliography 47 A TOI-1260 A1 x CHAPTER 1 Introduction For thousands of years the solar system planets were the only planets whose existence humanity was aware of. Iconic images of the planets and their moons obtained by famous Solar system missions, like the Pioneer, Mariner, Viking, Voyager and Cassini probes, have inspired generations of young minds. But our knowledge of planetary physics was completely based on the bodies gravitationally bound to our Sun. This began to change only a few decades ago when the family of known planets extended beyond the Solar system, when the first planets around a pulsar1 were unambiguously confirmed in 1992 (Wolszczan & Frail 1992), followed by the discovery of the first planet around a Sun-like star in 1995 (Mayor & Queloz 1995). The latter was awarded the Nobel prize in physics in 2019. Since these first discoveries, the field of exoplanetology has exploded. But why did it take so long? While a complete answer to this question is multi-faceted, possibly the sim- plest one is that exoplanets are billions of times fainter than their host stars. 1A compact stellar remnant, which emits electromagnetic pulses of radiation, mostly in radio. 1 Chapter 1 Introduction Adding the fact that they are small and far away, to this day, they are ex- tremely difficult to find by direct imaging, which is the first technique for astronomical observations that became available2.
Load more

Recommended publications
  • The Discovery of Exoplanets
    L'Univers, S´eminairePoincar´eXX (2015) 113 { 137 S´eminairePoincar´e New Worlds Ahead: The Discovery of Exoplanets Arnaud Cassan Universit´ePierre et Marie Curie Institut d'Astrophysique de Paris 98bis boulevard Arago 75014 Paris, France Abstract. Exoplanets are planets orbiting stars other than the Sun. In 1995, the discovery of the first exoplanet orbiting a solar-type star paved the way to an exoplanet detection rush, which revealed an astonishing diversity of possible worlds. These detections led us to completely renew planet formation and evolu- tion theories. Several detection techniques have revealed a wealth of surprising properties characterizing exoplanets that are not found in our own planetary system. After two decades of exoplanet search, these new worlds are found to be ubiquitous throughout the Milky Way. A positive sign that life has developed elsewhere than on Earth? 1 The Solar system paradigm: the end of certainties Looking at the Solar system, striking facts appear clearly: all seven planets orbit in the same plane (the ecliptic), all have almost circular orbits, the Sun rotation is perpendicular to this plane, and the direction of the Sun rotation is the same as the planets revolution around the Sun. These observations gave birth to the Solar nebula theory, which was proposed by Kant and Laplace more that two hundred years ago, but, although correct, it has been for decades the subject of many debates. In this theory, the Solar system was formed by the collapse of an approximately spheric giant interstellar cloud of gas and dust, which eventually flattened in the plane perpendicular to its initial rotation axis.
    [Show full text]
  • Exep Science Plan Appendix (SPA) (This Document)
    ExEP Science Plan, Rev A JPL D: 1735632 Release Date: February 15, 2019 Page 1 of 61 Created By: David A. Breda Date Program TDEM System Engineer Exoplanet Exploration Program NASA/Jet Propulsion Laboratory California Institute of Technology Dr. Nick Siegler Date Program Chief Technologist Exoplanet Exploration Program NASA/Jet Propulsion Laboratory California Institute of Technology Concurred By: Dr. Gary Blackwood Date Program Manager Exoplanet Exploration Program NASA/Jet Propulsion Laboratory California Institute of Technology EXOPDr.LANET Douglas Hudgins E XPLORATION PROGRAMDate Program Scientist Exoplanet Exploration Program ScienceScience Plan Mission DirectorateAppendix NASA Headquarters Karl Stapelfeldt, Program Chief Scientist Eric Mamajek, Deputy Program Chief Scientist Exoplanet Exploration Program JPL CL#19-0790 JPL Document No: 1735632 ExEP Science Plan, Rev A JPL D: 1735632 Release Date: February 15, 2019 Page 2 of 61 Approved by: Dr. Gary Blackwood Date Program Manager, Exoplanet Exploration Program Office NASA/Jet Propulsion Laboratory Dr. Douglas Hudgins Date Program Scientist Exoplanet Exploration Program Science Mission Directorate NASA Headquarters Created by: Dr. Karl Stapelfeldt Chief Program Scientist Exoplanet Exploration Program Office NASA/Jet Propulsion Laboratory California Institute of Technology Dr. Eric Mamajek Deputy Program Chief Scientist Exoplanet Exploration Program Office NASA/Jet Propulsion Laboratory California Institute of Technology This research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration. © 2018 California Institute of Technology. Government sponsorship acknowledged. Exoplanet Exploration Program JPL CL#19-0790 ExEP Science Plan, Rev A JPL D: 1735632 Release Date: February 15, 2019 Page 3 of 61 Table of Contents 1.
    [Show full text]
  • Exoplanetary Atmospheres: Key Insights, Challenges, and Prospects
    AA57CH15_Madhusudhan ARjats.cls August 7, 2019 14:11 Annual Review of Astronomy and Astrophysics Exoplanetary Atmospheres: Key Insights, Challenges, and Prospects Nikku Madhusudhan Institute of Astronomy, University of Cambridge, Cambridge CB3 0HA, United Kingdom; email: [email protected] Annu. Rev. Astron. Astrophys. 2019. 57:617–63 Keywords The Annual Review of Astronomy and Astrophysics is extrasolar planets, spectroscopy, planet formation, habitability, atmospheric online at astro.annualreviews.org composition https://doi.org/10.1146/annurev-astro-081817- 051846 Abstract Copyright © 2019 by Annual Reviews. Exoplanetary science is on the verge of an unprecedented revolution. The All rights reserved thousands of exoplanets discovered over the past decade have most recently been supplemented by discoveries of potentially habitable planets around nearby low-mass stars. Currently, the field is rapidly progressing toward de- tailed spectroscopic observations to characterize the atmospheres of these planets. Various surveys from space and the ground are expected to detect numerous more exoplanets orbiting nearby stars that make the planets con- ducive for atmospheric characterization. The current state of this frontier of exoplanetary atmospheres may be summarized as follows. We have entered the era of comparative exoplanetology thanks to high-fidelity atmospheric observations now available for tens of exoplanets. Access provided by Florida International University on 01/17/21. For personal use only. Annu. Rev. Astron. Astrophys. 2019.57:617-663. Downloaded from www.annualreviews.org Recent studies reveal a rich diversity of chemical compositions and atmospheric processes hitherto unseen in the Solar System. Elemental abundances of exoplanetary atmospheres place impor- tant constraints on exoplanetary formation and migration histories.
    [Show full text]
  • On the Detection of Exoplanets Via Radial Velocity Doppler Spectroscopy
    The Downtown Review Volume 1 Issue 1 Article 6 January 2015 On the Detection of Exoplanets via Radial Velocity Doppler Spectroscopy Joseph P. Glaser Cleveland State University Follow this and additional works at: https://engagedscholarship.csuohio.edu/tdr Part of the Astrophysics and Astronomy Commons How does access to this work benefit ou?y Let us know! Recommended Citation Glaser, Joseph P.. "On the Detection of Exoplanets via Radial Velocity Doppler Spectroscopy." The Downtown Review. Vol. 1. Iss. 1 (2015) . Available at: https://engagedscholarship.csuohio.edu/tdr/vol1/iss1/6 This Article is brought to you for free and open access by the Student Scholarship at EngagedScholarship@CSU. It has been accepted for inclusion in The Downtown Review by an authorized editor of EngagedScholarship@CSU. For more information, please contact [email protected]. Glaser: Detection of Exoplanets 1 Introduction to Exoplanets For centuries, some of humanity’s greatest minds have pondered over the possibility of other worlds orbiting the uncountable number of stars that exist in the visible universe. The seeds for eventual scientific speculation on the possibility of these "exoplanets" began with the works of a 16th century philosopher, Giordano Bruno. In his modernly celebrated work, On the Infinite Universe & Worlds, Bruno states: "This space we declare to be infinite (...) In it are an infinity of worlds of the same kind as our own." By the time of the European Scientific Revolution, Isaac Newton grew fond of the idea and wrote in his Principia: "If the fixed stars are the centers of similar systems [when compared to the solar system], they will all be constructed according to a similar design and subject to the dominion of One." Due to limitations on observational equipment, the field of exoplanetary systems existed primarily in theory until the late 1980s.
    [Show full text]
  • Simulating (Sub)Millimeter Observations of Exoplanet Atmospheres in Search of Water
    University of Groningen Kapteyn Astronomical Institute Simulating (Sub)Millimeter Observations of Exoplanet Atmospheres in Search of Water September 5, 2018 Author: N.O. Oberg Supervisor: Prof. Dr. F.F.S. van der Tak Abstract Context: Spectroscopic characterization of exoplanetary atmospheres is a field still in its in- fancy. The detection of molecular spectral features in the atmosphere of several hot-Jupiters and hot-Neptunes has led to the preliminary identification of atmospheric H2O. The Atacama Large Millimiter/Submillimeter Array is particularly well suited in the search for extraterrestrial water, considering its wavelength coverage, sensitivity, resolving power and spectral resolution. Aims: Our aim is to determine the detectability of various spectroscopic signatures of H2O in the (sub)millimeter by a range of current and future observatories and the suitability of (sub)millimeter astronomy for the detection and characterization of exoplanets. Methods: We have created an atmospheric modeling framework based on the HAPI radiative transfer code. We have generated planetary spectra in the (sub)millimeter regime, covering a wide variety of possible exoplanet properties and atmospheric compositions. We have set limits on the detectability of these spectral features and of the planets themselves with emphasis on ALMA. We estimate the capabilities required to study exoplanet atmospheres directly in the (sub)millimeter by using a custom sensitivity calculator. Results: Even trace abundances of atmospheric water vapor can cause high-contrast spectral ab- sorption features in (sub)millimeter transmission spectra of exoplanets, however stellar (sub) millime- ter brightness is insufficient for transit spectroscopy with modern instruments. Excess stellar (sub) millimeter emission due to activity is unlikely to significantly enhance the detectability of planets in transit except in select pre-main-sequence stars.
    [Show full text]
  • The Search for Exomoons and the Characterization of Exoplanet Atmospheres
    Corso di Laurea Specialistica in Astronomia e Astrofisica The search for exomoons and the characterization of exoplanet atmospheres Relatore interno : dott. Alessandro Melchiorri Relatore esterno : dott.ssa Giovanna Tinetti Candidato: Giammarco Campanella Anno Accademico 2008/2009 The search for exomoons and the characterization of exoplanet atmospheres Giammarco Campanella Dipartimento di Fisica Università degli studi di Roma “La Sapienza” Associate at Department of Physics & Astronomy University College London A thesis submitted for the MSc Degree in Astronomy and Astrophysics September 4th, 2009 Università degli Studi di Roma ―La Sapienza‖ Abstract THE SEARCH FOR EXOMOONS AND THE CHARACTERIZATION OF EXOPLANET ATMOSPHERES by Giammarco Campanella Since planets were first discovered outside our own Solar System in 1992 (around a pulsar) and in 1995 (around a main sequence star), extrasolar planet studies have become one of the most dynamic research fields in astronomy. Our knowledge of extrasolar planets has grown exponentially, from our understanding of their formation and evolution to the development of different methods to detect them. Now that more than 370 exoplanets have been discovered, focus has moved from finding planets to characterise these alien worlds. As well as detecting the atmospheres of these exoplanets, part of the characterisation process undoubtedly involves the search for extrasolar moons. The structure of the thesis is as follows. In Chapter 1 an historical background is provided and some general aspects about ongoing situation in the research field of extrasolar planets are shown. In Chapter 2, various detection techniques such as radial velocity, microlensing, astrometry, circumstellar disks, pulsar timing and magnetospheric emission are described. A special emphasis is given to the transit photometry technique and to the two already operational transit space missions, CoRoT and Kepler.
    [Show full text]
  • Precise Radial Velocities of Giant Stars
    A&A 555, A87 (2013) Astronomy DOI: 10.1051/0004-6361/201321714 & c ESO 2013 Astrophysics Precise radial velocities of giant stars V. A brown dwarf and a planet orbiting the K giant stars τ Geminorum and 91 Aquarii, David S. Mitchell1,2,SabineReffert1, Trifon Trifonov1, Andreas Quirrenbach1, and Debra A. Fischer3 1 Landessternwarte, Zentrum für Astronomie der Universität Heidelberg, Königstuhl 12, 69117 Heidelberg, Germany 2 Physics Department, California Polytechnic State University, San Luis Obispo, CA 93407, USA e-mail: [email protected] 3 Department of Astronomy, Yale University, New Haven, CT 06511, USA Received 16 April 2013 / Accepted 22 May 2013 ABSTRACT Aims. We aim to detect and characterize substellar companions to K giant stars to further our knowledge of planet formation and stellar evolution of intermediate-mass stars. Methods. For more than a decade we have used Doppler spectroscopy to acquire high-precision radial velocity measurements of K giant stars. All data for this survey were taken at Lick Observatory. Our survey includes 373 G and K giants. Radial velocity data showing periodic variations were fitted with Keplerian orbits using a χ2 minimization technique. Results. We report the presence of two substellar companions to the K giant stars τ Gem and 91 Aqr. The brown dwarf orbiting τ Gem has an orbital period of 305.5±0.1 days, a minimum mass of 20.6 MJ, and an eccentricity of 0.031±0.009. The planet orbiting 91 Aqr has an orbital period of 181.4 ± 0.1 days, a minimum mass of 3.2 MJ, and an eccentricity of 0.027 ± 0.026.
    [Show full text]
  • Exoplanet Exploration Collaboration Initiative TP Exoplanets Final Report
    EXO Exoplanet Exploration Collaboration Initiative TP Exoplanets Final Report Ca Ca Ca H Ca Fe Fe Fe H Fe Mg Fe Na O2 H O2 The cover shows the transit of an Earth like planet passing in front of a Sun like star. When a planet transits its star in this way, it is possible to see through its thin layer of atmosphere and measure its spectrum. The lines at the bottom of the page show the absorption spectrum of the Earth in front of the Sun, the signature of life as we know it. Seeing our Earth as just one possibly habitable planet among many billions fundamentally changes the perception of our place among the stars. "The 2014 Space Studies Program of the International Space University was hosted by the École de technologie supérieure (ÉTS) and the École des Hautes études commerciales (HEC), Montréal, Québec, Canada." While all care has been taken in the preparation of this report, ISU does not take any responsibility for the accuracy of its content. Electronic copies of the Final Report and the Executive Summary can be downloaded from the ISU Library website at http://isulibrary.isunet.edu/ International Space University Strasbourg Central Campus Parc d’Innovation 1 rue Jean-Dominique Cassini 67400 Illkirch-Graffenstaden Tel +33 (0)3 88 65 54 30 Fax +33 (0)3 88 65 54 47 e-mail: [email protected] website: www.isunet.edu France Unless otherwise credited, figures and images were created by TP Exoplanets. Exoplanets Final Report Page i ACKNOWLEDGEMENTS The International Space University Summer Session Program 2014 and the work on the
    [Show full text]
  • PLANETARY CANDIDATES OBSERVED by Kepler. VIII. a FULLY AUTOMATED CATALOG with MEASURED COMPLETENESS and RELIABILITY BASED on DATA RELEASE 25
    Draft version October 13, 2017 Typeset using LATEX twocolumn style in AASTeX61 PLANETARY CANDIDATES OBSERVED BY Kepler. VIII. A FULLY AUTOMATED CATALOG WITH MEASURED COMPLETENESS AND RELIABILITY BASED ON DATA RELEASE 25 Susan E. Thompson,1, 2, 3, ∗ Jeffrey L. Coughlin,2, 1 Kelsey Hoffman,1 Fergal Mullally,1, 2, 4 Jessie L. Christiansen,5 Christopher J. Burke,2, 1, 6 Steve Bryson,2 Natalie Batalha,2 Michael R. Haas,2, y Joseph Catanzarite,1, 2 Jason F. Rowe,7 Geert Barentsen,8 Douglas A. Caldwell,1, 2 Bruce D. Clarke,1, 2 Jon M. Jenkins,2 Jie Li,1 David W. Latham,9 Jack J. Lissauer,2 Savita Mathur,10 Robert L. Morris,1, 2 Shawn E. Seader,11 Jeffrey C. Smith,1, 2 Todd C. Klaus,2 Joseph D. Twicken,1, 2 Jeffrey E. Van Cleve,1 Bill Wohler,1, 2 Rachel Akeson,5 David R. Ciardi,5 William D. Cochran,12 Christopher E. Henze,2 Steve B. Howell,2 Daniel Huber,13, 14, 1, 15 Andrej Prša,16 Solange V. Ramírez,5 Timothy D. Morton,17 Thomas Barclay,18 Jennifer R. Campbell,2, 19 William J. Chaplin,20, 15 David Charbonneau,9 Jørgen Christensen-Dalsgaard,15 Jessie L. Dotson,2 Laurance Doyle,21, 1 Edward W. Dunham,22 Andrea K. Dupree,9 Eric B. Ford,23, 24, 25, 26 John C. Geary,9 Forrest R. Girouard,27, 2 Howard Isaacson,28 Hans Kjeldsen,15 Elisa V. Quintana,18 Darin Ragozzine,29 Avi Shporer,30 Victor Silva Aguirre,15 Jason H. Steffen,31 Martin Still,8 Peter Tenenbaum,1, 2 William F.
    [Show full text]
  • Lecture 21: the Doppler Effect
    Matthew Schwartz Lecture 21: The Doppler effect 1 Moving sources We’d like to understand what happens when waves are produced from a moving source. Let’s say we have a source emitting sound with the frequency ν. In this case, the maxima of the 1 amplitude of the wave produced occur at intervals of the period T = ν . If the source is at rest, an observer would receive these maxima spaced by T . If we draw the waves, the maxima are separated by a wavelength λ = Tcs, with cs the speed of sound. Now, say the source is moving at velocity vs. After the source emits one maximum, it moves a distance vsT towards the observer before it emits the next maximum. Thus the two successive maxima will be closer than λ apart. In fact, they will be λahead = (cs vs)T apart. The second maximum will arrive in less than T from the first blip. It will arrive with− period λahead cs vs Tahead = = − T (1) cs cs The frequency of the blips/maxima directly ahead of the siren is thus 1 cs 1 cs νahead = = = ν . (2) T cs vs T cs vs ahead − − In other words, if the source is traveling directly towards us, the frequency we hear is shifted c upwards by a factor of s . cs − vs We can do a similar calculation for the case in which the source is traveling directly away from us with velocity v. In this case, in between pulses, the source travels a distance T and the old pulse travels outwards by a distance csT .
    [Show full text]
  • Exoplanet Detection Techniques
    Exoplanet Detection Techniques Debra A. Fischer1, Andrew W. Howard2, Greg P. Laughlin3, Bruce Macintosh4, Suvrath Mahadevan5;6, Johannes Sahlmann7, Jennifer C. Yee8 We are still in the early days of exoplanet discovery. Astronomers are beginning to model the atmospheres and interiors of exoplanets and have developed a deeper understanding of processes of planet formation and evolution. However, we have yet to map out the full complexity of multi-planet architectures or to detect Earth analogues around nearby stars. Reaching these ambitious goals will require further improvements in instru- mentation and new analysis tools. In this chapter, we provide an overview of five observational techniques that are currently employed in the detection of exoplanets: optical and IR Doppler measurements, transit pho- tometry, direct imaging, microlensing, and astrometry. We provide a basic description of how each of these techniques works and discuss forefront developments that will result in new discoveries. We also highlight the observational limitations and synergies of each method and their connections to future space missions. Subject headings: 1. Introduction tary; in practice, they are not generally applied to the same sample of stars, so our detection of exoplanet architectures Humans have long wondered whether other solar sys- has been piecemeal. The explored parameter space of ex- tems exist around the billions of stars in our galaxy. In the oplanet systems is a patchwork quilt that still has several past two decades, we have progressed from a sample of one missing squares. to a collection of hundreds of exoplanetary systems. Instead of an orderly solar nebula model, we now realize that chaos 2.
    [Show full text]
  • Tidal Evolution of Exoplanetary Systems Hosting Potentially Habitable Exoplanets
    MNRAS 494, 5082–5090 (2020) doi:10.1093/mnras/staa1110 Advance Access publication 2020 April 26 Tidal evolution of exoplanetary systems hosting potentially habitable exoplanets. The cases of LHS-1140 b-c and K2-18 b-c G. O. Gomes 1,2‹ and S. Ferraz-Mello1 1 Instituto de Astronomia, Geof´ısica e Cienciasˆ Atmosfericas,´ IAG-USP, Rua do Matao˜ 1226, 05508-900 Sao˜ Paulo, Brazil Downloaded from https://academic.oup.com/mnras/article/494/4/5082/5825369 by Universidade de S�o Paulo user on 26 August 2020 2Observatoire de Geneve,` UniversitedeGen´ eve,` 51 Chemin des Maillettes, CH-1290 Sauverny, Switzerland Accepted 2020 April 19. Received 2020 April 19; in original form 2020 March 4 ABSTRACT We present a model to study secularly and tidally evolving three-body systems composed by two low-mass planets orbiting a star, in the case where the bodies rotation axes are always perpendicular to the orbital plane. The tidal theory allows us to study the spin and orbit evolution of both stiff Earth-like planets and predominantly gaseous Neptune-like planets. The model is applied to study two recently discovered exoplanetary systems containing potentially habitable exoplanets (PHE): LHS-1140 b-c and K2-18 b-c. For the former system, we show that both LHS-1140 b and c must be in nearly circular orbits. For K2-18 b-c, the combined analysis of orbital evolution time-scales with the current eccentricity estimation of K2-18 b allows us to conclude that the inner planet (K2-18 c) must be a Neptune-like gaseous body.
    [Show full text]