DOCSLIB.ORG

Lecture 10: Icy Bodies in Outer Solar System & Debris Disk Evolution

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Lecture 10: Icy Bodies in Outer Solar System & Debris Disk Evolution Star Formation and the Origins of Planetary Systems Lecture 10: Icy bodies in outer solar system & debris disk evolution Background reading: Credit: NASA Luu & Jewitt 2002, ARA&A ; Wyatt 2008, ARA&A; Hughes et al. 2018, ARA&A Thanks to M. Wyatt for slides on debris disks Logistical roundup (1/2): Problems accessing previously emailed link to lecture recordings were caused by default browser cookie settings. Probably possible to fix that, but easier solution below... Recorded Kaltura Live Room lectures are here now! Logistical roundup (2/2): Remaining questions from SPF #9 will be answered at the end of this lecture, not during the lecture summary. Please sign up for a time slot to give your presentation (via Doodle poll to be sent by Ewine) . Star Formation and the Origins of Planetary Systems Lecture 10: Icy bodies in outer solar system & debris disk evolution Background reading: Credit: NASA Luu & Jewitt 2002, ARA&A ; Wyatt 2008, ARA&A; Hughes et al. 2018, ARA&A Thanks to M. Wyatt for slides on debris disks 486958 Arrokoth • Classical Kuiper Belt Object • farthest & most primitive object visited by spacecraft • 21 + 15 km contact binary Lecture 10: Icy bodies in outer solar system & debris disk evolution Do you want to build a snowman? Background reading: Credit: NASA, Arrokoth Luu & Jewitt 2002, ARA&A ; Wyatt 2008, ARA&A; Hughes et al. 2018, ARA&A Thanks to M. Wyatt for slides on debris disks Quiz: What does the size of the contact binary components tell you about their collision velocities? Summary Lecture 9 Key point(s) Key figure/table 2. Planetesimal to Model planetesimal swarm statistically with distributions of important parameters. For a select few objects, achieve runaway growth from planetesimals into embryos up to isolation mass, embryo growth defined by Hill sphere. 3a. Terrestrial Isolation mass embryos in inner disk up to ~0.1 Mearth (from #2). Then need gravitational planet formation interactions to push embyos onto colliding orbits. Giant impact phase responsible for many scenario "odd features" of Solar System's terrestrial planets. Earth took ~80 Myr to form. In contrast, Jupiter took <3.8 Myr to form. Two classical models for gas giant formation: core 3b. Gas giant planet accretion & gravitational instability. Former takes nearly too long, latter requires massive, cold formation models disk at correct time in disk evolution. Alternative model: pebble accretion! Combined with streaming instability, it can solve most timescale problems for formation. Three kinds of migration within gas disk, depending on mass ratio of planet to star and disk to star. Type I moves planets inward; II & III are not exclusively in one direction. Observables of 4. Planet migration migration are spiral arms driven by planets and gaps (for certain sizes). Migration of planet can excite high eccentricities/inclinations in smaller planetesimals, leading to impacts. !7 SPF course progress: where are we now? Date SPF # Who Lecture 18 Feb. 1 EvD Motivation, history, & observational facilities 20 Feb. 2 EvD Pre-stellar cores, cloud collapse 25 Feb. 3 EvD SEDs, embedded protostars 27 Feb. 4 EvD Outflows & jets 3 Mar. 5 EvD High mass star formation 5 Mar. P1 TAs Practice exercises #1 (Star formation) 10 Mar. 6 MM Pre-main sequence star types, stellar birthline 12 Mar. 7 MM Circumstellar disks 24 Mar. 8 MM Disk evolution & planet formation (Planet formation) 26 Mar. 9 MM Planet formation: Jovian vs terrestrial planets 31 Mar. 10 MM Icy bodies in outer solar system, debris disk evolution 2 Apr. 11 EvD Condensation processes, meteorites, missions 7 Apr. 12 EvD Chondrules, planetary atmospheres 9 Apr. 13 MM Extrasolar planets 14 Apr. P2 TAs Practice exercises #2 16 Apr. 14 MM Astrobiology (Life formation) !8 Disk evolutionary stages overview SPF #8 Stage 1) Envelope infall 2) Viscous evolution 3) Disk clearing • Matter falls onto disk faster • Infall rate lower. Disk evolves viscously, Disk material already accreted than can be redistributed. under the action of its own friction. by protostar and protoplanets, Features • Global instabilities possible. • Outward angular momentum transport or driven away by energetic processes: • Disk grows with time. allows matter to fall in to star. (winds, photoevap., tidal encounters) 5 6 7 Depends on disk mass & environment: tff : ~ Few x 10 yr ~Few x 10 yr, up to 10 yr Timescale 103 − 107 yr after stage #2. SED Class Class 0, early Class I Late Class I, Class II (opt. thick disk) Class III (opt. thin disk) Pre-main sequence stars: Pre-main sequence star: Protostar Weak-lined T Tauris Star type Classical T Tauri − Herbig AeBe (Towards zero-age main sequence) Lectures SPF #3, #6 SPF #3, #6, #7, #8, #9 SPF #10 !9 Disk evolutionary stages overview SPF #8 Stage 1) Envelope infall 2) Viscous evolution 3) Disk clearing • Matter falls onto disk faster • Infall rate lower. Disk evolves viscously, Disk material already accreted than can be redistributed. under the action of its own friction. by protostar and protoplanets, Features • Global instabilities possible. • Outward angular momentum transport or driven away by energetic processes: • Disk grows with time. allows matter to fall in to star. (winds, photoevap., tidal encounters) 5 6 7 Depends on disk mass & environment: tff : ~ Few x 10 yr ~Few x 10 yr, up to 10 yr Timescale 103 − 107 yr after stage #2. SED Class Class 0, early Class I Late Class I, Class II (opt. thick disk) Class III (opt. thin disk) Pre-main sequence stars: Pre-main sequence star: Protostar Weak-lined T Tauris Star type Classical T Tauri − Herbig AeBe (Towards zero-age main sequence) Lectures SPF #3, #6 SPF #3, #6, #7, #8, #9 SPF #10 !10 2) Defining debris disks Haisch et al. (2001) (SPF#3, 8) Hernandez et al. (2007) (SPF#7) 50% 1) Disk clearing stage 2 Myr "protoplanetary" disk "debris" disk !11 (gassy) (rocky) 3) Solar System's Kuiper Belt & Oort Cloud 1. Protoplanetary disk evolutionary stage #3: disk clearing 2. Debris disks & their evolution 3. Analyze Solar System's Kuiper Belt & Oort Cloud as preserved remnants of #1 & #2 Disk clearing stage timescales Haisch et al. (2001) ▪ Jovian planet formation and migration must occur Hernandez et al. (2007) while gas still present in disk. ▪ Near-IR warm dust surveys show decreased fraction (Near-IR) of stars with disks in clusters after ~2 Myr SPF#7 Ansdell et al. (2016, 2017) 2 Myr ~1.5 Myr (Sub-mm) ≤3 Myr ▪ Some decrease also found in longer wavelength ≤5 mid- and far-IR surveys, but mm surveys show ≤10 Myr decrease only after 3 Myr, with some (cold outer) disks surviving up to 10 Myr. Disk evolution and dispersal, as seen through SEDs Multiple paths from protoplanetary (gas-rich, ‘thick’) to debris (gas-poor, ‘thin’) disks: Grain growth Disk + dispersal? SPF#8 Class II Class II Star ? Gap formation? SPF#8, 9 Class II Class III Merin et al. Quiz: In what order does the disk clear out in the sequence below? inner middle outer Hartmann et al. (2016) Disk Class II Star Class II Class III Mechanisms for disk dispersal ▪ Accretion onto star ▪ Material used for planet formation ▪ Stellar winds ▪ Photoevaporation ▪ External (e.g., Orion) ▪ stellar UV ▪ Close encounters with other stars ⇒ stripping Merin et al. Hollenbach et al. 2000, PPIV Photoevaporation Stellar or external UV heats surface layer of disk to high temperatures ⇒ thermal sound speed large enough to overcome gravitational pull ⇒ flow If layer stays neutral (PDR) ⇒ gas ≈ several 103 K If layer ionized ⇒ gas ≈ 104 K (SPF#6) photo- accretion evaporation Hollenbach et al. 2000, PPIV UV switch Alexander et al. (2014) Once accretion rate drops and cannot keep up anymore with photoevaporation rate, inner disk drains quickly "transition disk" = disk with inner hole or gap. Sometimes see "pre-transition" disk as gapped vs with hole. Hollenbach et al. (2000) 1. Protoplanetary disk evolutionary stage #3: disk clearing 2. Debris disks & their evolution 3. Analyze Solar System's Kuiper Belt & Oort Cloud as preserved remnants of #1 & #2 Debris disks Debris disks are (1) older disks which have (2) lost their gas and where dust is produced in situ by (3) collisions of planetesimals. Merin et al. Debris disks were originally the ‘Vega phenomenon’ ▪ Main sequence (MS) star, Vega (= α Lyrae) with circumstellar dust grains ▪ Calibration star for IRAS satellite → expected to see weak emission. Instead a powerful IR source was found, orders of magnitude brighter at 60 and 100 µm than Rayleigh- the photospheric emission Jeans tail Vega ▪ Vega was thus the first MS star apart from the Sun to have surrounding solid material. ▪ Thermal balance: small grains become hotter than big grains Aumann et al. (1984), Backman & Paresce in PPIII The first debris disk detections with IRAS satellite (1984): the Fab Four. Rayleigh- ▪ Spatially resolved Jeans tail Vega even by IRAS 60 µm Fomalhaut ▪ Distance well known ▪ No near-IR excess β Pic ε Eri (Aumann et al. 1984) Courtesy: Paul Kalas, www.disksite.com Grain sizes and mass ▪ Although planetesimals have formed in these disks, some fraction of grains must be smaller than ~100 µm to emit far-IR radiation ▪ Values of grain size and total grain area depend on emissivity exponent β or grain size distribution exponent m -3 -3 -2 ▪ Minimum mass: all grains have size d=d0 with density 1 gr cm → small masses 10 – 10 MEarth ▪ Maximum mass: assume grain size distribution n(d)∝d-3.5 produced by collisional fragmentation, -3 with dmin=d0, dmax=1000 km (size of gravitational instability at 100 AU) and density 5 gr cm → large masses up to 0.1 MSun Grain removal ▪ Small grains with 0.1 < d < 1 µm are ejected quickly (~104 yr) from system by radiation pressure.
Load more

Recommended publications
  • Protoplanetary Disks and Debris Disks
    Protoplanetary Disks and Debris Disks David J. Wilner Harvard-Smithsonian Center for Astrophysics Sean Andrews Meredith Hughes Chunhua Qi June 12, 2009 Millimeter and Submillimeter Astronomy, Taipei Image: NASA/JPL-Caltech/T. Pyle (SSC) Circumstellar Disks • inevitable consequence of gravity + angular momentum • integral part of star and planet formation paradigm 4 10 yr 105 yr 7 10 yr 108 yr 100 AU cloud collapse protostar protoplanetary disk planetary system and debris disk Marrois et al. 2008 J. Jørgensen Isella et al. 2007 Alves et al. 2001 2 This Talk • context: “protoplanetary” and “debris” disks • tool: submillimeter dust continuum emission • some recent SMA studies and implications 1. high resolution ρ Oph disk imaging survey - S. Andrews, D. Wilner, A.M. Hughes, C. Qi, K. Dullemond (arxiv:0906.0730) 2. resolved disk polarimetry: TW Hya, HD 163296 - A.M. Hughes, D. Wilner, J. Cho, D. Marrone, A. Lazarian, S. Andrews, R. Rao 3. debris disk imaging: HD 107146 - D. Wilner, J. Williams, S. Andrews, A.M. Hughes, C. Qi 3 “Protoplanetary” → “Debris” McCaughrean et al. 1995; Burrows et al. 1996 Corder et al 2009; Greaves et al. 2005 V. Pietu; Isella et al. 2007 Kalas et al. 2008; Marois et al. 2008 • age ~1 to 10 Myr • age up to Gyrs • gas and trace dust • dust and trace gas • dust particles are sticking, • planetesimals are colliding, growing into planetesimals creating new dust particles • mass 0.001 to 0.1 M • mass <1 Mmoon • mass distribution? • dust distribution → planets? • accretion/dispersal physics? • dynamical history? 4 Submillimeter Dust Emission x-ray uv optical infrared submm cm hot gas/accr.
    [Show full text]
  • Astro2020 Science White Paper Modeling Debris Disk Evolution
    Astro2020 Science White Paper Modeling Debris Disk Evolution Thematic Areas Planetary Systems Formation and Evolution of Compact Objects Star and Planet Formation Cosmology and Fundamental Physics Galaxy Evolution Resolved Stellar Populations and their Environments Stars and Stellar Evolution Multi-Messenger Astronomy and Astrophysics Principal Author András Gáspár Steward Observatory, The University of Arizona [email protected] 1-(520)-621-1797 Co-Authors Dániel Apai, Jean-Charles Augereau, Nicholas P. Ballering, Charles A. Beichman, Anthony Boc- caletti, Mark Booth, Brendan P. Bowler, Geoffrey Bryden, Christine H. Chen, Thayne Currie, William C. Danchi, John Debes, Denis Defrère, Steve Ertel, Alan P. Jackson, Paul G. Kalas, Grant M. Kennedy, Matthew A. Kenworthy, Jinyoung Serena Kim, Florian Kirchschlager, Quentin Kral, Sebastiaan Krijt, Alexander V. Krivov, Marc J. Kuchner, Jarron M. Leisenring, Torsten Löhne, Wladimir Lyra, Meredith A. MacGregor, Luca Matrà, Dimitri Mawet, Bertrand Mennes- son, Tiffany Meshkat, Amaya Moro-Martín, Erika R. Nesvold, George H. Rieke, Aki Roberge, Glenn Schneider, Andrew Shannon, Christopher C. Stark, Kate Y. L. Su, Philippe Thébault, David J. Wilner, Mark C. Wyatt, Marie Ygouf, Andrew N. Youdin Co-Signers Virginie Faramaz, Kevin Flaherty, Hannah Jang-Condell, Jérémy Lebreton, Sebastián Marino, Jonathan P. Marshall, Rafael Millan-Gabet, Peter Plavchan, Luisa M. Rebull, Jacob White Abstract Understanding the formation, evolution, diversity, and architectures of planetary systems requires detailed knowledge of all of their components. The past decade has shown a remarkable increase in the number of known exoplanets and debris disks, i.e., populations of circumstellar planetes- imals and dust roughly analogous to our solar system’s Kuiper belt, asteroid belt, and zodiacal dust.
    [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]
  • Solar System Debris Disk - S2D2
    Solar System Debris Disk - S2D2 Image credit: NASA/JPL-Caltech Proposal for Science Themes of ESA's L2 and L3 Missions Ralf Srama Universität Stuttgart, Institut für Raumfahrtsysteme Raumfahrtzentrum Baden Württemberg Pfaffenwaldring 29, 70569 Stuttgart [email protected] Tel. +49 711 6856 2511, Fax +49 711 685 63596 http://www.irs.uni-stuttgart.de 2 Solar System Debris Disk - S2D2 Contributors Eberhard Grün, Max-Planck-Institut für Kernphysik, Heidelberg, Germany Alexander Krivov, Astrophysikalisches Institut, Univ. Jena, Germany Rachel Soja, Institut für Raumfahrtsysteme, Univ. Stuttgart, Germany Veerle Sterken, Institut für Raumfahrtsysteme, Univ. Stuttgart, Germany Zoltan Sternovsky, LASP, Univ. of Colorado, Boulder, USA. Supporters listed at http://www.dsi.uni-stuttgart.de/cosmicdust/missions/debrisdisk/index.html 3 Solar System Debris Disk - S2D2 Summary from direct observations of the parent bodies. The sizes of these parent bodies range from Understanding the conditions for planet Near Earth Asteroids with sizes of a few 10 m, formation is the primary theme of ESA's to km-sized comet nuclei, to over 1000 km- Cosmic Vision plan. Planets and left-over sized Trans-Neptunian Objects. The inner small solar system bodies are witnesses and zodiacal dust cloud has been probed by remote samples of the processing in different regions sensing instruments at visible and infrared of the protoplanetary disk. Small bodies fill the wavelengths, micro crater counts, in situ dust whole solar system from the surface of the analyzers, meteor observations and recent sun, to the fringes of the solar system, and to sample return missions. Nevertheless, the the neighboring stellar system. This is covered dynamical and compositional interrelations by the second theme of Cosmic Vision.
    [Show full text]
  • Planets and Debris Disks
    Planets and Debris disks F. Marzari, S. Desidera, C. Lazzoni Dept. Of Physics and Astronomy and INAF, Padova, Italy What can PLATO tell us about this complex coexistence? Some facts about debris disks About 20% of solar type stars host debris disks (Eiroa et al. 2013 with DUNES-Herschel). They are signature in most cases of planetesimal belts leftover of planet formation. Many systems harbour cold and warm components possibly related to inner (asteroidal) and outer (Kuiper Belt like) planetesimal belts. Possible ambiguity in interpretation and radial distance location. Relavant possible correlations of debris disks with: Stellar age. Some mild decline with age but small number statistics (Wyatt 2008) Metallicity or spectral type. Too poor statistics Presence of exoplanets. Some correlation but weak (in particular with small planets). Correlation with external planets discovered by direct imaging. Formation of spirals and warping if the disk is directly imaged. Epsilon Eridani: Planetesimal belts: 1 or 2 in between 1-20 AU and another one beyond 64 AU. Need of a one or more planets inside the outer belt (40 AU?) to explain the dust-free zone (debated planet at 3.5 AU) (Su et al. 2017) Moro-Martin et al. (2010) Warm dust typical location: 0-10/20 au Possible origins Mutual collisions (or giant impacts if the star is young) in a local planetesimal belt Outgassing of comets similar to JFC comets: it requires a complex dynamical configuration similar to the Patel et al. (2014): stars within 75 pc solar system PR-drag inward migration of dust from an outer belt.
    [Show full text]
  • Debris Disks: the First 30 Years Where Will Herschel Take Us?
    With thanks to M. Wyatt, P. Kalas, L. Churcher, G. Duchene, B. Sibthorpe, A. Roberge Debris Disks: the first 30 years Where will Herschel take us? Brenda Matthews Herzberg Institute of Astrophysics & University of Victoria Outline • Debris disk: definition and discovery • Incidence and evolution • Characterizing debris disks • Disks around low-mass stars (AU Mic) • Planetary connection • Herschel surveys “Debris” Disks • Debris disks are produced from the remnants of the planet formation process • Second generation dust is produced through collisional processes • The debris disk can include – Planetesimal population (though not directly observable) – Dust produced (detectable from optical centimetre) • Dust may lie in belts at various radii from the star Solar System Debris Disk Kuiper Belt Asteroid Belt Debris Disk Snapshot: Zodiacal Light Photo: Stefan Binnewies "The light at its brightest was considerably fainter than the brighter" portions of the milky way... The outline generally appeared of a " parabolic or probably elliptical form, and it would seem excentric" as regards the sun, and also inclined, though but slightly to the ecliptic."" "-- Captain Jacob 1859 Discovery: Vega Phenomenon IRAS finds excess around 20% of main sequence stars (Rhee et al. 2007) Backman & Paresce 1993" "The Big Three"" The discovery of excess emission from main sequence stars at IRAS wavelengths (Aumann et al. 1984). Circumstellar Dust Disks Smith & Terrile 1984 Beta Pic was the Rosetta Stone Debris Disk for 15 years >300 refereed papers Dust must be second generation •! Debris disks cannot be the remnants of the protoplanetary disks found around pre-main sequence stars (Backman & Paresce 1993): –! The stars are old (e.g., up to 100s of Myr, even Gyr) –! The dust is small (< 100 micron) (Harper et al.
    [Show full text]
  • Tidal Detachment and Evaporation Following an Exoplanet-Star Collision
    MNRAS 000, 000–000 (0000) Preprint 24 June 2019 Compiled using MNRAS LATEX style file v3.0 Orphaned Exomoons: Tidal Detachment and Evaporation Following an Exoplanet-Star Collision Miguel Martinez1, Nicholas C. Stone1;2;3, Brian D. Metzger1 1Department of Physics and Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027, USA 2Racah Institute of Physics, The Hebrew University, Jerusalem, 91904, Israel 3Department of Astronomy, University of Maryland, College Park, MD 20742, USA 24 June 2019 ABSTRACT Gravitational perturbations on an exoplanet from a massive outer body, such as the Kozai- Lidov mechanism, can pump the exoplanet’s eccentricity up to values that will destroy it via a collision or strong interaction with its parent star. During the final stages of this process, any exomoons orbiting the exoplanet will be detached by the star’s tidal force and placed into orbit around the star. Using ensembles of three and four-body simulations, we demonstrate that while most of these detached bodies either collide with their star or are ejected from the system, a substantial fraction, ∼ 10%, of such "orphaned" exomoons (with initial properties similar to those of the Galilean satellites in our own solar system) will outlive their parent exoplanet. The detached exomoons generally orbit inside the ice line, so that strong radiative heating will evaporate any volatile-rich layers, producing a strong outgassing of gas and dust, analogous to a comet’s perihelion passage. Small dust grains ejected from the exomoon may help generate an opaque cloud surrounding the orbiting body but are quickly removed by radiation blow-out.
    [Show full text]
  • Debris Disks: Exploring the Environment and Evolution of Planetary Systems Prospects for Submillimeter Observational Studies in the Next Decade
    Debris disks: Exploring the environment and evolution of planetary systems Prospects for submillimeter observational studies in the next decade A White paper for the Astro2020 Decadal Survey Thematic area: Planetary Systems Wayne Holland*, UK ATC, Royal Observatory, Edinburgh, UK Mark Booth, Astrophysical Institute, Friedrich-Schiller University, Jena, Germany William Dent, Joint ALMA Observatory, Santiago, Chile Gaspard Duchêne, Astronomy Department, University of California, Berkeley, USA Pamela Klaassen, UK ATC, Royal Observatory, Edinburgh, UK Jean-François Lestrade, Observatoire de Paris, CNRS, Paris, France Jonathan Marshall, Academia Sinica, Taipei, Taiwan Brenda Matthews, NRC, Herzberg Astronomy & Astrophysics Programs, Victoria, Canada Summary Recent surveys have shown that exoplanets are near-ubiquitous around main sequence stars, but surprisingly little is known about their properties and the environments in which they reside. Planets and remnant planetesimal belts are produced in the gas- and dust-rich disks around nascent stars. Debris disks provide a unique way to study the demographics of planetary systems and how they evolve from their primordial structures. Observations tell us about the scale of the regions with planetesimals, the possible locations and masses of planets, and the composition and dynamics of the material present. Over the past decade optical/IR surveys have revealed new populations of disks, whilst millimetre-wave interferometers have given the first detailed views of planetesimal belts orbiting other
    [Show full text]
  • Cometary Impactors on the TRAPPIST-1 Planets Can Destroy All Planetary Atmospheres and Rebuild Secondary Atmospheres on Planets F, G, H
    Mon. Not. R. Astron. Soc. 000, 1{28 (2002) Printed 4 July 2018 (MN LATEX style file v2.2) Cometary impactors on the TRAPPIST-1 planets can destroy all planetary atmospheres and rebuild secondary atmospheres on planets f, g, h Quentin Kral,1? Mark C. Wyatt,1 Amaury H.M.J. Triaud,1;2 Sebastian Marino, 1 Philippe Th´ebault, 3 Oliver Shorttle, 1;4 1Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA, UK 2School of Physics & Astronomy, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK 3LESIA-Observatoire de Paris, UPMC Univ. Paris 06, Univ. Paris-Diderot, France 4Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ, UK Accepted 1928 December 15. Received 1928 December 14; in original form 1928 October 11 ABSTRACT The TRAPPIST-1 system is unique in that it has a chain of seven terrestrial Earth-like planets located close to or in its habitable zone. In this paper, we study the effect of potential cometary impacts on the TRAPPIST-1 planets and how they would affect the primordial atmospheres of these planets. We consider both atmospheric mass loss and volatile delivery with a view to assessing whether any sort of life has a chance to develop. We ran N-body simulations to investigate the orbital evolution of potential impacting comets, to determine which planets are more likely to be impacted and the distributions of impact velocities. We consider three scenarios that could potentially throw comets into the inner region (i.e within 0.1au where the seven planets are located) from an (as yet undetected) outer belt similar to the Kuiper belt or an Oort cloud: Planet scattering, the Kozai-Lidov mechanism and Galactic tides.
    [Show full text]
  • SEEDS – Direct Imaging Survey for Exoplanets and Disks
    SEEDS – Direct Imaging Survey for Exoplanets and Disks K. G. Helminiak 1,2, M. Kuzuhara3,4, T. Kudo3, M. Tamura3,5, T. Usuda1, J. Hashimoto6, T. Matsuo7, M. W. McElwain8, M. Momose9, T. Tsukagoshi9, and the SEEDS/HiCIAO team 1Subaru Telescope, National Astronomical Observatory of Japan, 650 North Aohoku Place, Hilo, HI 96720, USA 2Nicolaus Copernicus Astronomical Center, Department of Astrophysics, ul. Rabia´nska 8, 87-100 Toru´n,Poland 3National Astronomical Observatory Japan (NAOJ), Osawa 2-21-1, Mitaka, Tokyo 181-8588, Japan 4Department of Earth and Planetary Science, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 181-8588, Japan 5School of Science, The University of Tokyo, Hongo 7-3-1, Bunkyo, Tokyo 113-0033, Japan 6Department of Physics and Astronomy, The University of Oklahoma, 440 West Brooks Street, Norman, OK 73019, USA 7Department of Astronomy, Kyoto University, Kitashirakawa-Oiwake-cho, Sakyo-ku, Kyoto, Kyoto 606-8502, Japan 8Exoplanets and Stellar Astrophysics Laboratory, Code 667, Goddard Space Flight Center, Greenbelt, MD 20771, USA 9College of Science, Ibaraki University, Bunkyo 2-1-1, Mito 310-8512, Japan Abstract. Exoplanets on wide orbits (r & 10 AU) can be revealed by high-contrast direct imaging, which is efficient for their detailed detections and characterizations compared with indirect techniques. The SEEDS campaign, using the 8.2-m Subaru Telescope, is one of the most extensive campaigns to search for wide-orbit exoplanets via direct imaging. Since 2009 to date, the campaign has surveyed exoplanets around stellar targets selected from the solar neighborhood, moving groups, open clusters, and star- 750 SEEDS–DirectImagingSurveyforExoplanetsandDisks forming regions.
    [Show full text]
  • Perturbation of the Oort Cloud by Close Stellar Encounter with Gliese 710
    Bachelor Thesis University of Groningen Kapteyn Astronomical Institute Perturbation of the Oort Cloud by Close Stellar Encounter with Gliese 710 August 5, 2019 Author: Rens Juris Tesink Supervisors: Kateryna Frantseva and Nickolas Oberg Abstract Context: Our Sun is thought to have an Oort cloud, a spherically symmetric shell of roughly 1011 comets orbiting with semi major axes between ∼ 5 × 103 AU and 1 × 105 AU. It is thought to be possible that other stars also possess comet clouds. Gliese 710 is a star expected to have a close encounter with the Sun in 1.35 Myrs. Aims: To simulate the comet clouds around the Sun and Gliese 710 and investigate the effect of the close encounter. Method: Two REBOUND N-body simulations were used with the help of Gaia DR2 data. Simulation 1 had a total integration time of 4 Myr, a time-step of 1 yr, and 10,000 comets in each comet cloud. And Simulation 2 had a total integration time of 80,000 yr, a time-step of 0.01 yr, and 100,000 comets in each comet cloud. Results: Simulation 2 revealed a 1.7% increase in the semi-major axis at time of closest approach and a population loss of 0.019% - 0.117% for the Oort cloud. There was no statistically significant net change of the inclination of the comets during this encounter and a 0.14% increase in the eccentricity at the time of closest approach. Contents 1 Introduction 3 1.1 Comets . .3 1.2 New comets and the Oort cloud . .5 1.3 Structure of the Oort cloud .
    [Show full text]
  • An Evolving Astrobiology Glossary
    Bioastronomy 2007: Molecules, Microbes, and Extraterrestrial Life ASP Conference Series, Vol. 420, 2009 K. J. Meech, J. V. Keane, M. J. Mumma, J. L. Siefert, and D. J. Werthimer, eds. An Evolving Astrobiology Glossary K. J. Meech1 and W. W. Dolci2 1Institute for Astronomy, 2680 Woodlawn Drive, Honolulu, HI 96822 2NASA Astrobiology Institute, NASA Ames Research Center, MS 247-6, Moffett Field, CA 94035 Abstract. One of the resources that evolved from the Bioastronomy 2007 meeting was an online interdisciplinary glossary of terms that might not be uni- versally familiar to researchers in all sub-disciplines feeding into astrobiology. In order to facilitate comprehension of the presentations during the meeting, a database driven web tool for online glossary definitions was developed and participants were invited to contribute prior to the meeting. The glossary was downloaded and included in the conference registration materials for use at the meeting. The glossary web tool is has now been delivered to the NASA Astro- biology Institute so that it can continue to grow as an evolving resource for the astrobiology community. 1. Introduction Interdisciplinary research does not come about simply by facilitating occasions for scientists of various disciplines to come together at meetings, or work in close proximity. Interdisciplinarity is achieved when the total of the research expe- rience is greater than the sum of its parts, when new research insights evolve because of questions that are driven by new perspectives. Interdisciplinary re- search foci often attack broad, paradigm-changing questions that can only be answered with the combined approaches from a number of disciplines.
    [Show full text]