DOCSLIB.ORG

The Habitability and Stability of Earth-Like Planets in Binary Star Systems

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
The Habitability and Stability of Earth-Like Planets in Binary Star Systems THE HABITABILITY AND STABILITY OF EARTH-LIKE PLANETS IN BINARY STAR SYSTEMS by Nicholas W. Troup A thesis submitted to the Faculty of the University of Delaware in partial fulfillment of the requirements for the degree of Honors Bachelor of Science in Physics with Distinction May 2012 c 2012 Nicholas W. Troup All Rights Reserved THE HABITABILITY AND STABILITY OF EARTH-LIKE PLANETS IN BINARY STAR SYSTEMS by Nicholas W. Troup Approved: John E. Gizis, Ph.D. Professor in charge of thesis on behalf of the Advisory Committee Approved: James MacDonald, Ph.D. Committee member from the Department of Physics and Astronomy Approved: James Glancey, Ph.D. Committee member from the Board of Senior Thesis Readers Approved: Michael Arnold, Ph.D. Director, University Honors Program ACKNOWLEDGMENTS First and foremost, I would like to thank the members of my thesis committee for their guidance and support: Professor James Glancey foe proving a forum for peer feedback and provided a valuable lay-person's view on my work; Professor James MacDonald for providing me with valuable information on computational methods that proved crucial in the completion of my thesis; and many thanks to Professor John Gizis for always finding the time to meet with me, keeping me on track, providing advice, pointing me towards numerous valuable resources, and for being an overall marvelous mentor. I would also like to thank the University of Delaware for the free use of their UNIX computing clusters and the software package MATLAB. In addition, I must acknowledge the University of Delaware Undergraduate Research Program for their financial support, and for the people there who allow the Senior Thesis program to run smoothly. Many thanks to my fianc´eeChrissy for always being my cheerleader and moral support, and for reminding me that what I was doing was interesting and worthwhile. Finally, I would like to thank my parents. Without their unconditional love and sup- port, I would not be here today writing this thesis. iii This thesis is dedicated to the glory of God, the creator of the Heavens and the source of my passion. The heavens declare the glory of God; the skies proclaim the work of his hands. Day after day they pour forth speech; night after night they reveal knowledge. - Psalm 19:1-2 iv TABLE OF CONTENTS LIST OF TABLES :::::::::::::::::::::::::::::::: viii LIST OF FIGURES ::::::::::::::::::::::::::::::: ix ABSTRACT ::::::::::::::::::::::::::::::::::: xi Chapter 1 INTRODUCTION AND BACKGROUND :::::::::::::: 1 1.1 Criteria For Long-Term Habitability :::::::::::::::::: 1 1.1.1 The Habitable Zone :::::::::::::::::::::::: 1 1.1.2 Dynamical Stability :::::::::::::::::::::::: 2 1.2 Orbital Configurations :::::::::::::::::::::::::: 2 1.3 Lagrange Points :::::::::::::::::::::::::::::: 3 1.4 Overview and Goals ::::::::::::::::::::::::::: 5 1.4.1 Habitable Zone Geometry and Stability ::::::::::::: 6 1.4.2 Determining Critical Separations :::::::::::::::: 6 1.4.3 Investigation of Lagrange and Transfer Orbits ::::::::: 6 1.5 Restrictions and Scope :::::::::::::::::::::::::: 7 1.5.1 Stellar Type :::::::::::::::::::::::::::: 7 1.5.2 Orbital Inclination :::::::::::::::::::::::: 8 1.5.3 Orbital Eccentricity :::::::::::::::::::::::: 8 2 GENERAL SIMULATION METHODS :::::::::::::::: 9 2.1 Simulator Overview :::::::::::::::::::::::::::: 9 2.1.1 Simulation Set-Up :::::::::::::::::::::::: 9 2.1.2 Simulation Time Steps and Wrap-Up :::::::::::::: 11 v 2.1.3 Premature Ends to Simulations ::::::::::::::::: 11 2.2 Dynamical Simulation :::::::::::::::::::::::::: 12 2.2.1 KDK Method ::::::::::::::::::::::::::: 12 2.2.2 Lagrange Point Calculation ::::::::::::::::::: 13 2.3 Thermal Simulation :::::::::::::::::::::::::::: 13 2.3.1 Planetary Surface Temperature Calculation :::::::::: 14 2.3.2 Habitable Zone Determination :::::::::::::::::: 15 2.4 Verification :::::::::::::::::::::::::::::::: 15 2.4.1 Dynamics ::::::::::::::::::::::::::::: 16 2.4.2 Habitable Zone and Surface Temperature Verification ::::: 17 3 SIMULATIONS AND HYPOTHESIS ::::::::::::::::: 19 3.1 Critical Binary Separation for Planet Habitability in S-Type Systems 19 3.1.1 System Parameter Initialization ::::::::::::::::: 20 3.1.2 Simulation Time Step :::::::::::::::::::::: 20 3.2 Lagrange Point Habitability ::::::::::::::::::::::: 21 3.2.1 L4 Point Temperature Simulations ::::::::::::::: 21 3.2.2 Expected Behavior :::::::::::::::::::::::: 22 4 RESULTS AND DISCUSSION :::::::::::::::::::::: 25 4.1 Habitable Zone Geometry :::::::::::::::::::::::: 25 4.2 Transfer Orbits :::::::::::::::::::::::::::::: 27 4.3 S-Type Binary Results :::::::::::::::::::::::::: 27 4.3.1 Sensitivity of Stability and Planetary Eccentricity Perturbation 28 4.3.2 Critical Binary Separations ::::::::::::::::::: 28 4.3.3 Climate Effects of Abnormal Day-Night Cycles in S-type Binaries :::::::::::::::::::::::::::::: 31 4.4 Lagrange Point Habitability ::::::::::::::::::::::: 33 4.4.1 Comparison to Expected Behavior :::::::::::::::: 33 vi 4.4.2 Discussion ::::::::::::::::::::::::::::: 34 5 CONCLUSIONS AND FUTURE WORK ::::::::::::::: 37 5.1 Summary of Results ::::::::::::::::::::::::::: 37 5.2 Future Work :::::::::::::::::::::::::::::::: 38 5.2.1 Longer-Term and More Efficient Simulations :::::::::: 38 5.2.2 Testing the Odds of Planet Formation ::::::::::::: 39 5.2.3 Exploring Planetary Parameters ::::::::::::::::: 39 5.2.4 Orbital Eccentricities ::::::::::::::::::::::: 40 5.2.5 P-type Habitability :::::::::::::::::::::::: 41 5.2.6 L4/L5 Orbit Stability ::::::::::::::::::::::: 42 5.3 Conclusion ::::::::::::::::::::::::::::::::: 42 REFERENCES :::::::::::::::::::::::::::::::::: 43 vii LIST OF TABLES 2.1 Orbital parameters of the Earth, acquired from NASA's Planetary Fact Sheets[12], used to verify the correct simulation of orbital dynamics. :::::::::::::::::::::::::::::::: 16 3.1 Sample of time steps used to initialize simulations for the equal mass case. ::::::::::::::::::::::::::::::::::: 21 4.1 Comparison of the fitting coefficient C from Equation 4.4, and the function H(M; η) from Equation 3.11 for various mass ratios, η (right), and combined stellar masses, M = M1 + M2 (left). ::::: 34 viii LIST OF FIGURES 1.1 The two common orbital configurations for binary systems with planets. The heavier lines indicate planetary orbital paths, and lighter lines, the orbital path of the stars. :::::::::::::: 4 1.2 The 5 Lagrange Points of the Earth-Sun System with the James Webb Space Telescope orbiting at the L2 point (Not to Scale). Image Credit: NASA :::::::::::::::::::::::::::::: 5 2.1 Simulation Overview :::::::::::::::::::::::::: 10 2.2 Habitable Zone of the Sun, indicated by the green ring, with the position of Venus, Earth, and Mars plotted as small circles. Red indicates the area where the planet would be too warm, and blue, as well as white, indicates regions which are too cold. The Sun would be located at the bullseye of this target shape. All distances are in Astronomical Units (AU). ::::::::::::::::::::::: 17 2.3 Distance between the Earth and the Sun over the evolution of the test system for various time steps dt. ::::::::::::::::: 18 3.1 Overview of Lagrange Point simulation set-up :::::::::::: 23 4.1 Two main classes of Habitable Zone geometries(a and b), with two special cases of each (c and d). :::::::::::::::::::: 26 4.2 Surface Temperature of an Earth-like planet in an S-type orbit near Critical Binary Seperation with M1 = 1M , η = 1, and R = 3:43AU. 29 4.3 Minimum Habitable S-type Binary Separation plotted with the distance the planet needs to be from the host star to have T=288K with η = 1. ::::::::::::::::::::::::::::::: 30 4.4 Minimum Habitable S-type Binary Separation plotted for varying mass ratios. The line represents the equation of best fit. :::::: 31 ix 4.5 Overview of how a planet in an S-type binary orbit would experience day and night. ::::::::::::::::::::::::::::: 33 4.6 Surface Temperature of an Earth-like planet at the L4 point for various equal-mass binaries. The upper and lower horizontal lines represent the boiling point and freezing point of water, our criteria for planet habitability. ::::::::::::::::::::::::::: 35 4.7 Surface Temperature of an Earth-like planet at the L4 point for M1 = 1 and a variety of mass ratios. The upper and lower horizontal lines represent the boiling point and freezing point of water, our criteria for planet habitability. ::::::::::::::::::::: 36 5.1 Examples of eccentricity of orbits, with e = 0 representing a perfectly circular orbit, and larger e representing increasingly elliptical orbits. Image Credit: HyperPhysics, Georgia State University. ::::::: 41 x ABSTRACT In 2011, NASA's Kepler spacecraft observed the first planet to be detected in a known binary star system, Kepler 16-b. Its discovery has sparked new discussion on the potential of binary systems supporting habitable Earth-like planets. In this study, by using relatively simple computation models, we are able to shed new light and place new limitations on this discussion. Habitable Zone geometry in binary systems is discussed as a part of this study, in which we are able to classify binary habitable zones into two major classes of merged and unmerged, with important special cases of each class presented. We were able to learn a good deal about the behavior of planets in S-type binary orbits, and the possibility of life on those planets. The effect of the orbit of the planet on the climate as well as how the planet experiences day and night are discussed, and we also present a lower limit for the binary separation at which a binary system would fail to have
Load more

Recommended publications
  • Glossary - Cellbiology
    1 Glossary - Cellbiology Blotting: (Blot Analysis) Widely used biochemical technique for detecting the presence of specific macromolecules (proteins, mRNAs, or DNA sequences) in a mixture. A sample first is separated on an agarose or polyacrylamide gel usually under denaturing conditions; the separated components are transferred (blotting) to a nitrocellulose sheet, which is exposed to a radiolabeled molecule that specifically binds to the macromolecule of interest, and then subjected to autoradiography. Northern B.: mRNAs are detected with a complementary DNA; Southern B.: DNA restriction fragments are detected with complementary nucleotide sequences; Western B.: Proteins are detected by specific antibodies. Cell: The fundamental unit of living organisms. Cells are bounded by a lipid-containing plasma membrane, containing the central nucleus, and the cytoplasm. Cells are generally capable of independent reproduction. More complex cells like Eukaryotes have various compartments (organelles) where special tasks essential for the survival of the cell take place. Cytoplasm: Viscous contents of a cell that are contained within the plasma membrane but, in eukaryotic cells, outside the nucleus. The part of the cytoplasm not contained in any organelle is called the Cytosol. Cytoskeleton: (Gk. ) Three dimensional network of fibrous elements, allowing precisely regulated movements of cell parts, transport organelles, and help to maintain a cell’s shape. • Actin filament: (Microfilaments) Ubiquitous eukaryotic cytoskeletal proteins (one end is attached to the cell-cortex) of two “twisted“ actin monomers; are important in the structural support and movement of cells. Each actin filament (F-actin) consists of two strands of globular subunits (G-Actin) wrapped around each other to form a polarized unit (high ionic cytoplasm lead to the formation of AF, whereas low ion-concentration disassembles AF).
    [Show full text]
  • Solar System Simulator NASA SUMMER of INNOVATION
    National Aeronautics and Space Administration Solar System Simulator NASA SUMMER OF INNOVATION UNIT Earth and Space Science – Year of the Solar System DESCRIPTION This online software generates views of GRADE LEVELS the bodies of our planetary system at any th th 7 – 9 date from any artificial or natural point of observation. CONNECTION TO CURRICULUM Science and technology OBJECTIVES TEACHER PREPARATION TIME Students will: 1 hour • Investigate how to determine the relative position of the sun, LESSON TIME NEEDED planets, and a number of 30 minutes Complexity: Basic planetary spacecraft using a simple web-based program • Explore how planets change their position in space over time NATIONAL STANDARDS National Science Education Standards (NSTA) Science and Technology Standards • Abilities of technological design • Understanding about science and technology Earth and Space Science • Earth in the solar system • Objects in the sky Common Core State Standards for Mathematics (NCTM) Number and Operations in Base Ten • Perform operations with multi-digit whole numbers and with decimals to hundredths Operations and Algebraic Thinking • Generate and analyze patterns ISTE NETS and Performance Indicators for Students (ISTE) Creativity and Innovation • Use models and simulations to explore complex systems and issues. Technology Operations and Concepts • Understand and use technology systems Aerospace Education Services Project MANAGEMENT MATERIALS Take time to practice with this software. While simple, it offers a • Computer with Internet variety of views with which to become familiar. access On the simulator homepage, a FIELD OF VIEW of 2 will show the inner solar system very nicely. It will be difficult to see the position of ALL the planets at one time.
    [Show full text]
  • The Solar System
    5 The Solar System R. Lynne Jones, Steven R. Chesley, Paul A. Abell, Michael E. Brown, Josef Durech,ˇ Yanga R. Fern´andez,Alan W. Harris, Matt J. Holman, Zeljkoˇ Ivezi´c,R. Jedicke, Mikko Kaasalainen, Nathan A. Kaib, Zoran Kneˇzevi´c,Andrea Milani, Alex Parker, Stephen T. Ridgway, David E. Trilling, Bojan Vrˇsnak LSST will provide huge advances in our knowledge of millions of astronomical objects “close to home’”– the small bodies in our Solar System. Previous studies of these small bodies have led to dramatic changes in our understanding of the process of planet formation and evolution, and the relationship between our Solar System and other systems. Beyond providing asteroid targets for space missions or igniting popular interest in observing a new comet or learning about a new distant icy dwarf planet, these small bodies also serve as large populations of “test particles,” recording the dynamical history of the giant planets, revealing the nature of the Solar System impactor population over time, and illustrating the size distributions of planetesimals, which were the building blocks of planets. In this chapter, a brief introduction to the different populations of small bodies in the Solar System (§ 5.1) is followed by a summary of the number of objects of each population that LSST is expected to find (§ 5.2). Some of the Solar System science that LSST will address is presented through the rest of the chapter, starting with the insights into planetary formation and evolution gained through the small body population orbital distributions (§ 5.3). The effects of collisional evolution in the Main Belt and Kuiper Belt are discussed in the next two sections, along with the implications for the determination of the size distribution in the Main Belt (§ 5.4) and possibilities for identifying wide binaries and understanding the environment in the early outer Solar System in § 5.5.
    [Show full text]
  • Theoretical Orbits of Planets in Binary Star Systems 1
    Theoretical Orbits of Planets in Binary Star Systems 1 Theoretical Orbits of Planets in Binary Star Systems S.Edgeworth 2001 Table of Contents 1: Introduction 2: Large external orbits 3: Small external orbits 4: Eccentric external orbits 5: Complex external orbits 6: Internal orbits 7: Conclusion Theoretical Orbits of Planets in Binary Star Systems 2 1: Introduction A binary star system consists of two stars which orbit around their joint centre of mass. A large proportion of stars belong to such systems. What sorts of orbits can planets have in a binary star system? To examine this question we use a computer program called a multi-body gravitational simulator. This enables us to create accurate simulations of binary star systems with planets, and to analyse how planets would really behave in this complex environment. Initially we examine the simplest type of binary star system, which satisfies these conditions:- 1. The two stars are of equal mass. 2, The two stars share a common circular orbit. 3. Planets orbit on the same plane as the stars. 4. Planets are of negligible mass. 5. There are no tidal effects. We use the following units:- One time unit = the orbital period of the star system. One distance unit = the distance between the two stars. We can classify possible planetary orbits into two types. A planet may have an internal orbit, which means that it orbits around just one of the two stars. Alternatively, a planet may have an external orbit, which means that its orbit takes it around both stars. Also a planet's orbit may be prograde (in the same direction as the stars' orbits ), or retrograde (in the opposite direction to the stars' orbits).
    [Show full text]
  • A Day in the Life of Your Data
    A Day in the Life of Your Data A Father-Daughter Day at the Playground April, 2021 “I believe people are smart and some people want to share more data than other people do. Ask them. Ask them every time. Make them tell you to stop asking them if they get tired of your asking them. Let them know precisely what you’re going to do with their data.” Steve Jobs All Things Digital Conference, 2010 Over the past decade, a large and opaque industry has been amassing increasing amounts of personal data.1,2 A complex ecosystem of websites, apps, social media companies, data brokers, and ad tech firms track users online and offline, harvesting their personal data. This data is pieced together, shared, aggregated, and used in real-time auctions, fueling a $227 billion-a-year industry.1 This occurs every day, as people go about their daily lives, often without their knowledge or permission.3,4 Let’s take a look at what this industry is able to learn about a father and daughter during an otherwise pleasant day at the park. Did you know? Trackers are embedded in Trackers are often embedded Data brokers collect and sell, apps you use every day: the in third-party code that helps license, or otherwise disclose average app has 6 trackers.3 developers build their apps. to third parties the personal The majority of popular Android By including trackers, developers information of particular individ- and iOS apps have embedded also allow third parties to collect uals with whom they do not have trackers.5,6,7 and link data you have shared a direct relationship.3 with them across different apps and with other data that has been collected about you.
    [Show full text]
  • Binary and Multiple Systems of Asteroids
    Binary and Multiple Systems Andrew Cheng1, Andrew Rivkin2, Patrick Michel3, Carey Lisse4, Kevin Walsh5, Keith Noll6, Darin Ragozzine7, Clark Chapman8, William Merline9, Lance Benner10, Daniel Scheeres11 1JHU/APL [[email protected]] 2JHU/APL [[email protected]] 3University of Nice-Sophia Antipolis/CNRS/Observatoire de la Côte d'Azur [[email protected]] 4JHU/APL [[email protected]] 5University of Nice-Sophia Antipolis/CNRS/Observatoire de la Côte d'Azur [[email protected]] 6STScI [[email protected]] 7Harvard-Smithsonian Center for Astrophysics [[email protected]] 8SwRI [[email protected]] 9SwRI [[email protected]] 10JPL [[email protected]] 11Univ Colorado [[email protected]] Abstract A sizable fraction of small bodies, including roughly 15% of NEOs, is found in binary or multiple systems. Understanding the formation processes of such systems is critical to understanding the collisional and dynamical evolution of small body systems, including even dwarf planets. Binary and multiple systems provide a means of determining critical physical properties (masses, densities, and rotations) with greater ease and higher precision than is available for single objects. Binaries and multiples provide a natural laboratory for dynamical and collisional investigations and may exhibit unique geologic processes such as mass transfer or even accretion disks. Missions to many classes of planetary bodies – asteroids, Trojans, TNOs, dwarf planets – can offer enhanced science return if they target binary or multiple systems. Introduction Asteroid lightcurves were often interpreted through the 1970s and 1980s as showing evidence for satellites, and occultations of stars by asteroids also provided tantalizing if inconclusive hints that asteroid satellites may exist.
    [Show full text]
  • The Life Services Toolkit Resources and Tools to Support You and Your Beneficiary
    Life Insurance The Life Services Toolkit Resources and Tools to Support You and Your Beneficiary Group Life insurance through your employer gives you assurance that your family will receive some financial assistance in the event of a death. But coverage under a group Life policy from Standard Insurance Company (The Standard) does more than help protect your family from financial hardship after a loss. We have partnered with Health AdvocateSM to offer a lineup of additional services that can make a difference now and in the future. Online tools and services can help you create a will, make advance funeral plans and put your finances in order. After a loss, your beneficiary can consult experts by phone or in person, and obtain other helpful information online. The Life Services Toolkit is automatically available to those insured under a group Life insurance policy from The Standard. Services to Help You Now Visit the Life Services Toolkit website at standard.com/mytoolkit and enter user name “assurance” for information and tools to help you make important life decisions. • Estate Planning Assistance: Online tools walk you through the steps to prepare a will and create other documents, such as living wills, powers of attorney and advance directives. • Financial Planning: Consult online services to help you manage debt, calculate mortgage and loan payments, and take care of other financial matters with confidence. • Health and Wellness: Timely articles about nutrition, stress management and wellness help employees and their families lead healthy lives. • Identity Theft Prevention: Check the website for ways to thwart identity thieves and resolve issues if identity theft occurs.
    [Show full text]
  • Lifewater-Mwash-Training-Manual
    Our Mission We are Christians committed to ending the global water and sanitation crisis. Our Vision Thousands equipped, millions served, and a movement of transformed people serving together to end the global water and sanitation crisis. About Lifewater International Lifewater is a non-profit, Christian water development organization dedicated to effectively serving vulnerable children and families by partnering with underserved communities to overcome water poverty. With experience in more than 40 countries over 37 years, Lifewater serves all people of all faiths. Our programs are strategically prioritized to serve vulnerable children and families living in remote, rural, and hard-to-reach regions of our world. As a Christian organization, we are called by Jesus to love and serve the poor in an empowering and transformational manner. While some Christian organizations are called to feed the hungry, shelter the homeless, or plant churches, Lifewater International is called to bring water, health, and hope to the world’s most vulnerable people using our community-focused approach. We believe, as Jesus taught, that when we serve the poor, we are serving Him. We treat each community, family, and person with dignity and respect. We view every interaction as an opportunity to reflect God’s love in world and in deed. “But in your hearts revere Christ as Lord. Always be prepared to give an answer to everyone who asks you to give the reason for the hope that you have. But do this with gentleness and respect.” 1 Peter 3:15 (NIV) Lifewater International is a 501(c)(3) non-profit. Copyright This training material is published by Lifewater, Inc.
    [Show full text]
  • Origins of Life in the Universe Zackary Johnson
    11/4/2007 Origins of Life in the Universe Zackary Johnson OCN201 Fall 2007 [email protected] Zackary Johnson http://www.soest.hawaii.edu/oceanography/zij/education.html Uniiiversity of Hawaii Department of Oceanography Class Schedule Nov‐2Originsof Life and the Universe Nov‐5 Classification of Life Nov‐7 Primary Production Nov‐9Consumers Nov‐14 Evolution: Processes (Steward) Nov‐16 Evolution: Adaptation() (Steward) Nov‐19 Marine Microbiology Nov‐21 Benthic Communities Nov‐26 Whale Falls (Smith) Nov‐28 The Marine Food Web Nov‐30 Community Ecology Dec‐3 Fisheries Dec‐5Global Ecology Dec‐12 Final Major Concepts TIMETABLE Big Bang! • Life started early, but not at the beginning, of Earth’s Milky Way (and other galaxies formed) history • Abiogenesis is the leading hypothesis to explain the beginning of life on Earth • There are many competing theories as to how this happened • Some of the details have been worked out, but most Formation of Earth have not • Abiogenesis almost certainly occurred in the ocean 20‐15 15‐94.5Today Billions of Years Before Present 1 11/4/2007 Building Blocks TIMETABLE Big Bang! • Universe is mostly hydrogen (H) and helium (He); for Milky Way (and other galaxies formed) example –the sun is 70% H, 28% He and 2% all else! Abundance) e • Most elements of interest to biology (C, N, P, O, etc.) were (Relativ 10 produced via nuclear fusion Formation of Earth Log at very high temperature reactions in large stars after Big Bang 20‐13 13‐94.7Today Atomic Number Billions of Years Before Present ORIGIN OF LIFE ON EARTH Abiogenesis: 3 stages Divine Creation 1.
    [Show full text]
  • 1 on the Origin of the Pluto System Robin M. Canup Southwest Research Institute Kaitlin M. Kratter University of Arizona Marc Ne
    On the Origin of the Pluto System Robin M. Canup Southwest Research Institute Kaitlin M. Kratter University of Arizona Marc Neveu NASA Goddard Space Flight Center / University of Maryland The goal of this chapter is to review hypotheses for the origin of the Pluto system in light of observational constraints that have been considerably refined over the 85-year interval between the discovery of Pluto and its exploration by spacecraft. We focus on the giant impact hypothesis currently understood as the likeliest origin for the Pluto-Charon binary, and devote particular attention to new models of planet formation and migration in the outer Solar System. We discuss the origins conundrum posed by the system’s four small moons. We also elaborate on implications of these scenarios for the dynamical environment of the early transneptunian disk, the likelihood of finding a Pluto collisional family, and the origin of other binary systems in the Kuiper belt. Finally, we highlight outstanding open issues regarding the origin of the Pluto system and suggest areas of future progress. 1. INTRODUCTION For six decades following its discovery, Pluto was the only known Sun-orbiting world in the dynamical vicinity of Neptune. An early origin concept postulated that Neptune originally had two large moons – Pluto and Neptune’s current moon, Triton – and that a dynamical event had both reversed the sense of Triton’s orbit relative to Neptune’s rotation and ejected Pluto onto its current heliocentric orbit (Lyttleton, 1936). This scenario remained in contention following the discovery of Charon, as it was then established that Pluto’s mass was similar to that of a large giant planet moon (Christy and Harrington, 1978).
    [Show full text]
  • Arxiv:2012.04712V1 [Astro-Ph.EP] 8 Dec 2020 Direct Evidence of the Presence of Planets (E.G., ALMA Part- Nership Et Al
    DRAFT VERSION DECEMBER 10, 2020 Typeset using LATEX twocolumn style in AASTeX63 First detection of orbital motion for HD 106906 b: A wide-separation exoplanet on a Planet Nine-like orbit MEIJI M. NGUYEN,1 ROBERT J. DE ROSA,2 AND PAUL KALAS1, 3, 4 1Department of Astronomy, University of California, Berkeley, CA 94720, USA 2European Southern Observatory, Alonso de Cordova´ 3107, Vitacura, Santiago, Chile 3SETI Institute, Carl Sagan Center, 189 Bernardo Ave., Mountain View, CA 94043, USA 4Institute of Astrophysics, FORTH, GR-71110 Heraklion, Greece (Received August 26, 2020; Revised October 8, 2020; Accepted October 10, 2020) Submitted to AJ ABSTRACT HD 106906 is a 15 Myr old short-period (49 days) spectroscopic binary that hosts a wide-separation (737 au) planetary-mass ( 11 M ) common proper motion companion, HD 106906 b. Additionally, a circumbinary ∼ Jup debris disk is resolved at optical and near-infrared wavelengths that exhibits a significant asymmetry at wide separations that may be driven by gravitational perturbations from the planet. In this study we present the first detection of orbital motion of HD 106906 b using Hubble Space Telescope images spanning a 14 yr period. We achieve high astrometric precision by cross-registering the locations of background stars with the Gaia astromet- ric catalog, providing the subpixel location of HD 106906 that is either saturated or obscured by coronagraphic optical elements. We measure a statistically significant 31:8 7:0 mas eastward motion of the planet between ± the two most constraining measurements taken in 2004 and 2017. This motion enables a measurement of the +27 +27 inclination between the orbit of the planet and the inner debris disk of either 36 14 deg or 44 14 deg, depending on the true orientation of the orbit of the planet.
    [Show full text]
  • Rescuing Biodiversity to Safeguard Life on Earth Version 14 May 2020
    Draft proposal for a European Partnership under Horizon Europe Rescuing Biodiversity to Safeguard Life on Earth Version 14 May 2020 Summary This Partnership will provide an overarching platform connecting national/local and European Research & Innovation programs and combining in-cash and in-kind resources in support of one goal: by 2030 biodiversity in Europe is back on a path of recovery. It will co- develop multidisciplinary R&I programs with stakeholders, set up a European network of harmonized observatories for biodiversity monitoring, and implement a broad range of activities to increase relevance, impact and visibility of R&I and EU leadership in tackling the biodiversity crisis, in line with the European Green Deal and the new EU Biodiversity Strategy for 2030. 1 About this draft In autumn 2019 the Commission services asked potential partners to further elaborate proposals for the candidate European Partnerships identified during the strategic planning of Horizon Europe. These proposals have been developed by potential partners based on common guidance and template, taking into account the initial concepts developed by the Commission and feedback received from Member States during early consultation1. The Commission Services have guided revisions during drafting to facilitate alignment with the overall EU political ambition and compliance with the criteria for Partnerships. This document is a stable draft of the partnership proposal, released for the purpose of ensuring transparency of information on the current status of preparation (including on the process for developing the Strategic Research and Innovation Agenda). As such, it aims to contribute to further collaboration, synergies and alignment between partnership candidates, as well as more broadly with related R&I stakeholders in the EU, and beyond where relevant.
    [Show full text]