Today in Astronomy 111: the Kuiper Belt and the Oort Cloud
Total Page:16
File Type:pdf, Size:1020Kb
Load more
Recommended publications
-
Modeling Super-Earth Atmospheres in Preparation for Upcoming Extremely Large Telescopes
Modeling Super-Earth Atmospheres In Preparation for Upcoming Extremely Large Telescopes Maggie Thompson1 Jonathan Fortney1, Andy Skemer1, Tyler Robinson2, Theodora Karalidi1, Steph Sallum1 1University of California, Santa Cruz, CA; 2Northern Arizona University, Flagstaff, AZ ExoPAG 19 January 6, 2019 Seattle, Washington Image Credit: NASA Ames/JPL-Caltech/T. Pyle Roadmap Research Goals & Current Atmosphere Modeling Selecting Super-Earths for State of Super-Earth Tool (Past & Present) Follow-Up Observations Detection Preliminary Assessment of Future Observatories for Conclusions & Upcoming Instruments’ Super-Earths Future Work Capabilities for Super-Earths M. Thompson — ExoPAG 19 01/06/19 Research Goals • Extend previous modeling tool to simulate super-Earth planet atmospheres around M, K and G stars • Apply modified code to explore the parameter space of actual and synthetic super-Earths to select most suitable set of confirmed exoplanets for follow-up observations with JWST and next-generation ground-based telescopes • Inform the design of advanced instruments such as the Planetary Systems Imager (PSI), a proposed second-generation instrument for TMT/GMT M. Thompson — ExoPAG 19 01/06/19 Current State of Super-Earth Detections (1) Neptune Mass Range of Interest Earth Data from NASA Exoplanet Archive M. Thompson — ExoPAG 19 01/06/19 Current State of Super-Earth Detections (2) A Approximate Habitable Zone Host Star Spectral Type F G K M Data from NASA Exoplanet Archive M. Thompson — ExoPAG 19 01/06/19 Atmosphere Modeling Tool Evolution of Atmosphere Model • Solar System Planets & Moons ~ 1980’s (e.g., McKay et al. 1989) • Brown Dwarfs ~ 2000’s (e.g., Burrows et al. 2001) • Hot Jupiters & Other Giant Exoplanets ~ 2000’s (e.g., Fortney et al. -
Planetary Report Report
The PLANETARYPLANETARY REPORT REPORT Volume XXI Number 2 March/April 2001 Farewell, Mir Inside— The Planetary Society’s Cosmos 1: The First Solar Sail On the Cover: Volume XXI When Mir launched in February 1986, it was a show- Table of Number 2 case of Russian technology. But after 15 years of hard work, the aged space station has ended its run. Contents March/April 2001 This view of Mir over Earth’s blue skies was imaged during a fly-around by the space shuttle Atlantis follow- ing the joint docking activities between the two crews. Image: JSC/NASA Features Farewell to a Cold Warrior: Mir Station Obituary 4 As head of the Space Research Institute of the Soviet Academy of Sciences, Roald Sagdeev was there at the birth of the Mir space station. As an adviser to Soviet leader Mikhail Gorbachev, he watched Mir’s changing role in international space policy. Then, after marrying From Susan Eisenhower, the American president’s granddaughter, he moved to the United States The and saw Mir from a different perspective. A member of The Planetary Society’s Board of Editor Directors, he shares with Society members his memories of the long-lived space station. 8 A Bold New Voyage: he Planetary Society is preparing to The Planetary Society Prepares to Fly a Solar Sail It’s the first time a membership organization has undertaken an actual space mission, and launch its first space mission: the T only The Planetary Society is audacious enough to do it. This is the story of how we plan to Cosmos 1 solar sail. -
Arxiv:2001.00125V1 [Astro-Ph.EP] 1 Jan 2020
Draft version January 3, 2020 Typeset using LATEX default style in AASTeX61 SIZE AND SHAPE CONSTRAINTS OF (486958) ARROKOTH FROM STELLAR OCCULTATIONS Marc W. Buie,1 Simon B. Porter,1 et al. 1Southwest Research Institute 1050 Walnut St., Suite 300, Boulder, CO 80302 USA To be submitted to Astronomical Journal, Version 1.1, 2019/12/30 ABSTRACT We present the results from four stellar occultations by (486958) Arrokoth, the flyby target of the New Horizons extended mission. Three of the four efforts led to positive detections of the body, and all constrained the presence of rings and other debris, finding none. Twenty-five mobile stations were deployed for 2017 June 3 and augmented by fixed telescopes. There were no positive detections from this effort. The event on 2017 July 10 was observed by SOFIA with one very short chord. Twenty-four deployed stations on 2017 July 17 resulted in five chords that clearly showed a complicated shape consistent with a contact binary with rough dimensions of 20 by 30 km for the overall outline. A visible albedo of 10% was derived from these data. Twenty-two systems were deployed for the fourth event on 2018 Aug 4 and resulted in two chords. The combination of the occultation data and the flyby results provides a significant refinement of the rotation period, now estimated to be 15.9380 ± 0.0005 hours. The occultation data also provided high-precision astrometric constraints on the position of the object that were crucial for supporting the navigation for the New Horizons flyby. This work demonstrates an effective method for obtaining detailed size and shape information and probing for rings and dust on distant Kuiper Belt objects as well as being an important source of positional data that can aid in spacecraft navigation that is particularly useful for small and distant bodies. -
The Subsurface Habitability of Small, Icy Exomoons J
A&A 636, A50 (2020) Astronomy https://doi.org/10.1051/0004-6361/201937035 & © ESO 2020 Astrophysics The subsurface habitability of small, icy exomoons J. N. K. Y. Tjoa1,?, M. Mueller1,2,3, and F. F. S. van der Tak1,2 1 Kapteyn Astronomical Institute, University of Groningen, Landleven 12, 9747 AD Groningen, The Netherlands e-mail: [email protected] 2 SRON Netherlands Institute for Space Research, Landleven 12, 9747 AD Groningen, The Netherlands 3 Leiden Observatory, Leiden University, Niels Bohrweg 2, 2300 RA Leiden, The Netherlands Received 1 November 2019 / Accepted 8 March 2020 ABSTRACT Context. Assuming our Solar System as typical, exomoons may outnumber exoplanets. If their habitability fraction is similar, they would thus constitute the largest portion of habitable real estate in the Universe. Icy moons in our Solar System, such as Europa and Enceladus, have already been shown to possess liquid water, a prerequisite for life on Earth. Aims. We intend to investigate under what thermal and orbital circumstances small, icy moons may sustain subsurface oceans and thus be “subsurface habitable”. We pay specific attention to tidal heating, which may keep a moon liquid far beyond the conservative habitable zone. Methods. We made use of a phenomenological approach to tidal heating. We computed the orbit averaged flux from both stellar and planetary (both thermal and reflected stellar) illumination. We then calculated subsurface temperatures depending on illumination and thermal conduction to the surface through the ice shell and an insulating layer of regolith. We adopted a conduction only model, ignoring volcanism and ice shell convection as an outlet for internal heat. -
Quaoar from Multi-Chord Stellar Occultations
The Astrophysical Journal, 773:26 (13pp), 2013 August 10 doi:10.1088/0004-637X/773/1/26 C 2013. The American Astronomical Society. All rights reserved. Printed in the U.S.A. THE SIZE, SHAPE, ALBEDO, DENSITY, AND ATMOSPHERIC LIMIT OF TRANSNEPTUNIAN OBJECT (50000) QUAOAR FROM MULTI-CHORD STELLAR OCCULTATIONS F. Braga-Ribas1,2,28, B. Sicardy2,3,J.L.Ortiz4, E. Lellouch2, G. Tancredi5, J. Lecacheux2, R. Vieira-Martins1,6,7, J. I. B. Camargo1, M. Assafin7, R. Behrend8,F.Vachier6, F. Colas6, N. Morales4, A. Maury9, M. Emilio10,A.Amorim11, E. Unda-Sanzana12, S. Roland5, S. Bruzzone5, L. A. Almeida13, C. V. Rodrigues13, C. Jacques14, R. Gil-Hutton15, L. Vanzi16,A.C.Milone13, W. Schoenell4,11, R. Salvo5, L. Almenares5,E.Jehin17, J. Manfroid17, S. Sposetti18, P. Tanga19, A. Klotz20, E. Frappa21, P. Cacella22, J. P. Colque12, C. Neves10, E. M. Alvarez23, M. Gillon17, E. Pimentel14, B. Giacchini14, F. Roques2, T. Widemann2, V. S. Magalhaes˜ 13, A. Thirouin4, R. Duffard4, R. Leiva16, I. Toledo24, J. Capeche5, W. Beisker25, J. Pollock26,C.E.Cedeno˜ Montana˜ 13, K. Ivarsen27, D. Reichart27, J. Haislip27, and A. Lacluyze27 1 Observatorio´ Nacional, Rio de Janeiro, Brazil; [email protected] 2 Observatoire de Paris, LESIA, F-92195 Meudon, France 3 Universite´ Pierre et Marie Curie, F-75252 Paris, France 4 Instituto de Astrof´ısica de Andaluc´ıa-CSIC, E-18080 Granada, Spain 5 Observatorio Astronomico Los Molinos, Montevideo U-12400, Uruguay 6 Observatoire de Paris, IMCCE, F-75014 Paris, France 7 Observatorio´ do Valongo/UFRJ, Rio de Janeiro, Brazil 8 Observatoire -
Astronomy Educator Profiles
Astronomy Educator Profiles Alexis Ann Acohido graduated of the University of Hawaii at Manoa in 2015, where she obtained her Bachelor’s of Science in mathematics. Born and raised on Oahu, she moved to Hawai‘i island last year and is currently part of the Public Information and Outreach department at Gemini Observatory in Hilo, Hawai‘i. In 2013, she was part of the Akamai Workforce Initiative and interned at the Institute for Astronomy on Maui where she worked on parallax ranging methods for point source objects. Alexis Ann Acohido Gemini Observatory Contact: [email protected] Christian Andersen is the Operations Manager at the Pacific International Space Center for Exploration Systems (PISCES), and leads the agency’s additive manufacturing & construction projects at its Laser Lava Lab. Andersen started his career conducting research in inertial confinement fusion at Lawrence Livermore National Laboratory, Ecole Polytechnique, and Rutherford Appleton Laboratories. As Operations Manager, he’s worked on a variety of PISCES projects in transitioning aerospace technologies to terrestrial applications and analogue field testing. Andersen is also a Lecturer and Affiliate Faculty in the Physics & Astronomy Department at the University of Hawaii at Hilo, and the Vice- Chair of the Space Resources Technical Committee for the AIAA (American Institute of Aeronautics and Astronautics). He holds a B.S. in Physics from San Jose State University and a M.S. in Engineering from Christian Andersen U.C. Davis. PISCES Contact: [email protected] Virginia Aragon-Barnes had a passion for science and a natural curiosity about how and why things worked from a very early age. -
Mass of the Kuiper Belt · 9Th Planet PACS 95.10.Ce · 96.12.De · 96.12.Fe · 96.20.-N · 96.30.-T
Celestial Mechanics and Dynamical Astronomy manuscript No. (will be inserted by the editor) Mass of the Kuiper Belt E. V. Pitjeva · N. P. Pitjev Received: 13 December 2017 / Accepted: 24 August 2018 The final publication ia available at Springer via http://doi.org/10.1007/s10569-018-9853-5 Abstract The Kuiper belt includes tens of thousands of large bodies and millions of smaller objects. The main part of the belt objects is located in the annular zone between 39.4 au and 47.8 au from the Sun, the boundaries correspond to the average distances for orbital resonances 3:2 and 2:1 with the motion of Neptune. One-dimensional, two-dimensional, and discrete rings to model the total gravitational attraction of numerous belt objects are consid- ered. The discrete rotating model most correctly reflects the real interaction of bodies in the Solar system. The masses of the model rings were determined within EPM2017—the new version of ephemerides of planets and the Moon at IAA RAS—by fitting spacecraft ranging observations. The total mass of the Kuiper belt was calculated as the sum of the masses of the 31 largest trans-neptunian objects directly included in the simultaneous integration and the estimated mass of the model of the discrete ring of TNO. The total mass −2 is (1.97 ± 0.30) · 10 m⊕. The gravitational influence of the Kuiper belt on Jupiter, Saturn, Uranus and Neptune exceeds at times the attraction of the hypothetical 9th planet with a mass of ∼ 10 m⊕ at the distances assumed for it. -
Arxiv:1009.3071V1 [Astro-Ph.EP] 16 Sep 2010 Eovdfo T Aetsa–R Oiae Yrflce Lig Reflected by Dominated AU– Star–Are 1 Parent About Al Its Than the from Larger Stars
ApJ accepted Exoplanet albedo spectra and colors as a function of planet phase, separation, and metallicity Kerri L. Cahoy, Mark S. Marley NASA Ames Research Center, Moffett Field, CA 94035 [email protected] and Jonathan J. Fortney University of California Santa Cruz, Santa Cruz, CA 95064 ABSTRACT First generation space-based optical coronagraphic telescopes will obtain images of cool gas and ice giant exoplanets around nearby stars. The albedo spectra of exoplan- ets lying at planet-star separations larger than about 1 AU–where an exoplanet can be resolved from its parent star–are dominated by reflected light to beyond 1 µm and are punctuated by molecular absorption features. Here we consider how exoplanet albedo spectra and colors vary as a function of planet-star separation, metallicity, mass, and observed phase for Jupiter and Neptune analogs from 0.35 to 1 µm. We model Jupiter analogs with 1 and 3 the solar abundance of heavy elements, and Neptune analogs × × with 10 and 30 solar abundance of heavy elements. Our model planets orbit a solar × × analog parent star at separations of 0.8 AU, 2 AU, 5 AU, and 10 AU. We use a radiative- convective model to compute temperature-pressure profiles. The giant exoplanets are found to be cloud-free at 0.8 AU, possess H2O clouds at 2 AU, and have both NH3 arXiv:1009.3071v1 [astro-ph.EP] 16 Sep 2010 and H2O clouds at 5 AU and 10 AU. For each model planet we compute moderate resolution (R = λ/∆λ 800) albedo spectra as a function of phase. -
Publication in the Bulletin
Lunar and Planetary Information Bulletin July 2019 • Issue 157 Contents Featured Story From the Desk of Lori Glaze News From Space Meeting Highlights Spotlight on Education In Memoriam Milestones New and Noteworthy Calendar Featured Story Featured Story A Personal Journey to Ultima Thule: New Horizons in the Kuiper Belt As the New Horizons science team gathered in Laurel, Paul Schenk, Brian May, Joel Parker, and Andy Chaikin discuss a possible shape model for Ultima Thule, January 1, 2019. Credit: E. Whitman. Maryland, during the last week of 2018, many of us reflected back on a similar gathering three-and-a-half years earlier. In the summer of 2015, we all came together on a voyage of exploration to the planet Pluto and its moons. At that time, we didn’t know very much about our target, and this time we knew even less about “Ultima Thule,” a small, lonely 30-kilometer- wide object known as 2014 MU69 that was orbiting the Sun almost half a billion kilometers beyond Pluto. Unlike what we knew about Pluto, we did not even know Ultima Thule’s surface composition, its shape, or even the length of its day. We knew Ultima Thule was much smaller than — and hence would be a very different beast from — Pluto. So as the New Horizons team arrived at the Applied Physics Laboratory (APL) in Laurel, Maryland, to watch and enjoy the encounter sequence play out, we were completely in the dark. The only clues we had were stellar occultation observations of Ultima Thule from Argentina in 2017 that indicated it was elongate and might have either two separate or contacting lobes. -
Precision Astrometry for Fundamental Physics – Gaia
Gravitation astrometric tests in the external Solar System: the QVADIS collaboration goals M. Gai, A. Vecchiato Istituto Nazionale di Astrofisica [INAF] Osservatorio Astrofisico di Torino [OATo] WAG 2015 M. Gai - INAF-OATo - QVADIS 1 High precision astrometry as a tool for Fundamental Physics Micro-arcsec astrometry: Current precision goals of astrometric infrastructures: a few 10 µas, down to a few µas 1 arcsec (1) 5 µrad 1 micro-arcsec (1 µas) 5 prad Reference cases: • Gaia – space – visible range • VLTI – ground – near infrared range • VLBI – ground – radio range WAG 2015 M. Gai - INAF-OATo - QVADIS 2 ESA mission – launched Dec. 19th, 2013 Expected precision on individual bright stars: 1030 µas WAG 2015 M. Gai - INAF-OATo - QVADIS 3 Spacetime curvature around massive objects 1.5 G: Newton’s 1".74 at Solar limb 8.4 rad gravitational constant GM 1 cos d: distance Sun- 1 1 observer c2d 1 cos M: solar mass 0.5 c: speed of light Deflection [arcsec] angle : angular distance of the source to the Sun 0 0 1 2 3 4 5 6 Distance from Sun centre [degs] Light deflection Apparent variation of star position, related to the gravitational field of the Sun ASTROMETRY WAG 2015 M. Gai - INAF-OATo - QVADIS 4 Precision astrometry for Fundamental Physics – Gaia WAG 2015 M. Gai - INAF-OATo - QVADIS 5 Precision astrometry for Fundamental Physics – AGP Talk A = Apparent star position measurement AGP: G = Testing gravitation in the solar system Astrometric 1) Light deflection close to the Sun Gravitation 2) High precision dynamics in Solar System Probe P = Medium size space mission - ESA M4 (2014) Design driver: light bending around the Sun @ μas fraction WAG 2015 M. -
The Longevity of Water Ice on Ganymedes and Europas Around Migrated Giant Planets
The Astrophysical Journal, 839:32 (9pp), 2017 April 10 https://doi.org/10.3847/1538-4357/aa67ea © 2017. The American Astronomical Society. All rights reserved. The Longevity of Water Ice on Ganymedes and Europas around Migrated Giant Planets Owen R. Lehmer1, David C. Catling1, and Kevin J. Zahnle2 1 Dept. of Earth and Space Sciences/Astrobiology Program, University of Washington, Seattle, WA, USA; [email protected] 2 NASA Ames Research Center, Moffett Field, CA, USA Received 2017 February 17; revised 2017 March 14; accepted 2017 March 18; published 2017 April 11 Abstract The gas giant planets in the Solar System have a retinue of icy moons, and we expect giant exoplanets to have similar satellite systems. If a Jupiter-like planet were to migrate toward its parent star the icy moons orbiting it would evaporate, creating atmospheres and possible habitable surface oceans. Here, we examine how long the surface ice and possible oceans would last before being hydrodynamically lost to space. The hydrodynamic loss rate from the moons is determined, in large part, by the stellar flux available for absorption, which increases as the giant planet and icy moons migrate closer to the star. At some planet–star distance the stellar flux incident on the icy moons becomes so great that they enter a runaway greenhouse state. This runaway greenhouse state rapidly transfers all available surface water to the atmosphere as vapor, where it is easily lost from the small moons. However, for icy moons of Ganymede’s size around a Sun-like star we found that surface water (either ice or liquid) can persist indefinitely outside the runaway greenhouse orbital distance. -
ÉRIS Thèmes De Sa Découverte
Carmela Di Martine – Juin 2020 ÉRIS Thèmes de sa découverte Astronomie La première prise de cliché de l’astre date du 3 septembre 1954 au Mont Palomar en Californie. Éris a été ensuite photographiée lors d’observations effectuées le 21 octobre 2003, avec le télescope Oschin du Mont Palomar par l’équipe de Mike Brown, Chadwick Trujillo et David Rabinowitz. Mais ce n’est en fait que le 5 janvier 2005 qu’elle fut vraiment découverte, lorsque des photographies du même pan de ciel révélèrent son déplacement. Éris et Dysnomie Sous la désignation provisoire 2003 UB313 est officiellement classé « planète naine » le 24 août 2006 par l’Union astronomique internationale. Après avoir été désignée sous différents noms (Xena, Lila, Perséphone, Érèbe...), le « choix » final de la dénomination d’Éris par l’UAI, le 13 septembre 2006, évoque aussi d’une part les discussions et controverses acharnées entre scientifiques sur la remise en cause de la définition du mot « planète » du fait de sa découverte, et d’autre part, l’apparente diversité des orbites des objets épars de cette zone du Système solaire (au-delà de la ceinture de Kuiper) par rapport aux orbites régulières des planètes plus proches du Soleil (jusqu’à Neptune). Sa désignation scientifique officielle complète est (136199) Éris. Pour les principales caractéristiques d’Éris, lire aussi mon article : « Les planètes » (p. 25-27). Astrologie N’aurait-on pas une vision "patriarcale" d’Éris ? Éris la "semeuse de Discordes"… Éris, "l’Emmerdeuse"… Expressions très, trop facilement accordées aussi aux femmes par les hommes… Car des questions se posent tout de même… Pourquoi n’est-ce pas Thétis la « plus Belle » en ce jour de son mariage ? Pourquoi le choix d’Aphrodite embarrasse tant toute l’Assemblé divine qui n’en est pourtant pas habituellement à une guerre près ? Contre toute attente, les thèmes de découvertes d’Éris vont nous dévoiler en effet une toute autre vérité….