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Dynamical Evolution of the Hungaria Asteroids ⇑ Firth M
Icarus 210 (2010) 644–654 Contents lists available at ScienceDirect Icarus journal homepage: www.elsevier.com/locate/icarus Dynamical evolution of the Hungaria asteroids ⇑ Firth M. McEachern, Matija C´ uk , Sarah T. Stewart Department of Earth and Planetary Sciences, Harvard University, 20 Oxford Street, Cambridge, MA 02138, USA article info abstract Article history: The Hungarias are a stable asteroid group orbiting between Mars and the main asteroid belt, with high Received 29 June 2009 inclinations (16–30°), low eccentricities (e < 0.18), and a narrow range of semi-major axes (1.78– Revised 2 August 2010 2.06 AU). In order to explore the significance of thermally-induced Yarkovsky drift on the population, Accepted 7 August 2010 we conducted three orbital simulations of a 1000-particle grid in Hungaria a–e–i space. The three simu- Available online 14 August 2010 lations included asteroid radii of 0.2, 1.0, and 5.0 km, respectively, with run times of 200 Myr. The results show that mean motion resonances—martian ones in particular—play a significant role in the destabili- Keywords: zation of asteroids in the region. We conclude that either the initial Hungaria population was enormous, Asteroids or, more likely, Hungarias must be replenished through collisional or dynamical means. To test the latter Asteroids, Dynamics Resonances, Orbital possibility, we conducted three more simulations of the same radii, this time in nearby Mars-crossing space. We find that certain Mars crossers can be trapped in martian resonances, and by a combination of chaotic diffusion and the Yarkovsky effect, can be stabilized by them. -
Lurking in the Shadows: Wide-Separation Gas Giants As Tracers of Planet Formation
Lurking in the Shadows: Wide-Separation Gas Giants as Tracers of Planet Formation Thesis by Marta Levesque Bryan In Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy CALIFORNIA INSTITUTE OF TECHNOLOGY Pasadena, California 2018 Defended May 1, 2018 ii © 2018 Marta Levesque Bryan ORCID: [0000-0002-6076-5967] All rights reserved iii ACKNOWLEDGEMENTS First and foremost I would like to thank Heather Knutson, who I had the great privilege of working with as my thesis advisor. Her encouragement, guidance, and perspective helped me navigate many a challenging problem, and my conversations with her were a consistent source of positivity and learning throughout my time at Caltech. I leave graduate school a better scientist and person for having her as a role model. Heather fostered a wonderfully positive and supportive environment for her students, giving us the space to explore and grow - I could not have asked for a better advisor or research experience. I would also like to thank Konstantin Batygin for enthusiastic and illuminating discussions that always left me more excited to explore the result at hand. Thank you as well to Dimitri Mawet for providing both expertise and contagious optimism for some of my latest direct imaging endeavors. Thank you to the rest of my thesis committee, namely Geoff Blake, Evan Kirby, and Chuck Steidel for their support, helpful conversations, and insightful questions. I am grateful to have had the opportunity to collaborate with Brendan Bowler. His talk at Caltech my second year of graduate school introduced me to an unexpected population of massive wide-separation planetary-mass companions, and lead to a long-running collaboration from which several of my thesis projects were born. -
Mid-Band Gravitational Wave Detection with Precision Atomic Sensors
Mid-band gravitational wave detection with precision atomic sensors Peter W. Graham Stanford Institute for Theoretical Physics, Department of Physics, Stanford University, Stanford, CA 94305 Jason M. Hogan Department of Physics, Stanford University, Stanford, CA 94305 E-mail: [email protected] Mark A. Kasevich Department of Physics, Stanford University, Stanford, CA 94305 Surjeet Rajendran Berkeley Center for Theoretical Physics, Department of Physics, University of California, Berkeley, CA 94720 Roger W. Romani Kavli Institute for Particle Astrophysics and Cosmology Department of Physics, Stanford University, Stanford, CA 94305. For the MAGIS collaboration Abstract. We assess the science reach and technical feasibility of a satellite mission based on precision atomic sensors configured to detect gravitational radiation. Conceptual advances in the past three years indicate that a two-satellite constellation with science payloads consisting of atomic sensors based on laser cooled atomic Sr can achieve scientifically interesting gravitational wave strain sensitivities in a frequency band between the LISA and LIGO detectors, roughly 30 mHz to 10 Hz. The discovery arXiv:1711.02225v1 [astro-ph.IM] 6 Nov 2017 potential of the proposed instrument ranges from from observation of new astrophysical sources (e.g. black hole and neutron star binaries) to searches for cosmological sources of stochastic gravitational radiation and searches for dark matter. Mid-band gravitational wave detection with precision atomic sensors 2 1. Overview The recent first direct detections of gravitational waves by LIGO represent the beginning of a new era in astronomy [1, 2, 3]. Gravitational wave astronomy can provide information about astrophysical systems and cosmology that is difficult or impossible to acquire by other methods. -
A Hot Subdwarf-White Dwarf Super-Chandrasekhar Candidate
A hot subdwarf–white dwarf super-Chandrasekhar candidate supernova Ia progenitor Ingrid Pelisoli1,2*, P. Neunteufel3, S. Geier1, T. Kupfer4,5, U. Heber6, A. Irrgang6, D. Schneider6, A. Bastian1, J. van Roestel7, V. Schaffenroth1, and B. N. Barlow8 1Institut fur¨ Physik und Astronomie, Universitat¨ Potsdam, Haus 28, Karl-Liebknecht-Str. 24/25, D-14476 Potsdam-Golm, Germany 2Department of Physics, University of Warwick, Coventry, CV4 7AL, UK 3Max Planck Institut fur¨ Astrophysik, Karl-Schwarzschild-Straße 1, 85748 Garching bei Munchen¨ 4Kavli Institute for Theoretical Physics, University of California, Santa Barbara, CA 93106, USA 5Texas Tech University, Department of Physics & Astronomy, Box 41051, 79409, Lubbock, TX, USA 6Dr. Karl Remeis-Observatory & ECAP, Astronomical Institute, Friedrich-Alexander University Erlangen-Nuremberg (FAU), Sternwartstr. 7, 96049 Bamberg, Germany 7Division of Physics, Mathematics and Astronomy, California Institute of Technology, Pasadena, CA 91125, USA 8Department of Physics and Astronomy, High Point University, High Point, NC 27268, USA *[email protected] ABSTRACT Supernova Ia are bright explosive events that can be used to estimate cosmological distances, allowing us to study the expansion of the Universe. They are understood to result from a thermonuclear detonation in a white dwarf that formed from the exhausted core of a star more massive than the Sun. However, the possible progenitor channels leading to an explosion are a long-standing debate, limiting the precision and accuracy of supernova Ia as distance indicators. Here we present HD 265435, a binary system with an orbital period of less than a hundred minutes, consisting of a white dwarf and a hot subdwarf — a stripped core-helium burning star. -
Mission to Catch Comet ISON
Mission to Catch Comet ISON Andrew Cheng (JHU/APL; [email protected]) Steve Arnold (JHU/APL) Pietro Bernasconi (JHU/APL) Karl Hibbitts (JHU/APL) Eliot Young (SwRI) Tibor Kremic (GRC) Comet ISON . Comet ISON discovered September, 2012 An Oort Cloud comet believed to be making its first apparition . ISON perihelion in November, 2013 A sun-grazer which may not survive perihelion passage intact Observe the comet before perihelion . An important target of opportunity To study volatile-rich material from the epoch of planet formation To learn how comets work 26 May 2013 2 Oort Cloud Comets • Provide clues to the origins of the Solar System • Consist of pris8ne, icy material that was never heated in the inner solar system In late 2013, ISON may become the brightest Oort Cloud comet to appear in decades Comet Ikeya-Seki, sun-grazer of 1965 Comet McNaught in 2007 26 May 2013 3 Comet ISON Observability • Comet ISON is observable from the Northern Hemisphere, with solar elongaon >40°, from September 15, 2013 through Nov 12, 2013 • ISON becomes steadily brighter through this period • ISON may remain spectacularly bright aer December, 2013 Vitali Nevski and Artyom Novichonok, discoverers (space.com) 26 May 2013 4 Comet ISON Brightness . Observations are consistent with V~12 at time of BRRISON flight . Due to small solar elongation, additional observations BRRISON flight prior to flight are not expected CIOC web site, sungrazer.nrl.navy.mil 12 June 2013 BRRISON Project Review 3 5 What is BRRISON? . BRRISON = Balloon Rapid Response for the comet ISON Goal is to observe the comet ISON from a balloon platform Leverages the balloon study concepts Coordinate the science measurements with the greater scientific community, including ground and space observations 12 months from comet discovery to mission . -
Naming the Extrasolar Planets
Naming the extrasolar planets W. Lyra Max Planck Institute for Astronomy, K¨onigstuhl 17, 69177, Heidelberg, Germany [email protected] Abstract and OGLE-TR-182 b, which does not help educators convey the message that these planets are quite similar to Jupiter. Extrasolar planets are not named and are referred to only In stark contrast, the sentence“planet Apollo is a gas giant by their assigned scientific designation. The reason given like Jupiter” is heavily - yet invisibly - coated with Coper- by the IAU to not name the planets is that it is consid- nicanism. ered impractical as planets are expected to be common. I One reason given by the IAU for not considering naming advance some reasons as to why this logic is flawed, and sug- the extrasolar planets is that it is a task deemed impractical. gest names for the 403 extrasolar planet candidates known One source is quoted as having said “if planets are found to as of Oct 2009. The names follow a scheme of association occur very frequently in the Universe, a system of individual with the constellation that the host star pertains to, and names for planets might well rapidly be found equally im- therefore are mostly drawn from Roman-Greek mythology. practicable as it is for stars, as planet discoveries progress.” Other mythologies may also be used given that a suitable 1. This leads to a second argument. It is indeed impractical association is established. to name all stars. But some stars are named nonetheless. In fact, all other classes of astronomical bodies are named. -
The Blurring Distinction Between Asteroids and Comets
Answers Research Journal 8 (2015):203–208. www.answersingenesis.org/arj/v8/asteroids-and-comets.pdf The Blurring Distinction between Asteroids and Comets Danny R. Faulkner, Answers in Genesis, PO Box 510, Hebron, Kentucky, 41048. Abstract Asteroids and comets long had been viewed as distinct objects with regards to orbits and composition. However, discoveries made in recent years have blurred those distinctions. Whether there is a continuum on which our older conception of asteroids and comets are extremes or if there still is a gap between them is not entirely clear yet. Some of the newer views of comets and asteroids may challenge the evolutionary theory of the solar system. Additionally, the new information may challenge the idea that the solar system is billions of years old. For readers not versed in nomenclature of small solar system bodies, I discuss that in the appendix. Keywords: small solar system objects, comets, asteroids (minor planets) Introduction the sun, and their orbits frequently are inclined The differences between asteroids and comets considerably to the orbits of the planets. Because of At one time, we thought of asteroids and comets as their highly elliptical orbits, most comets alternately being two very different groups of objects. Comets and are very close to the sun when near perihelion and asteroids certainly looked different. Comets can be very far from the sun when near aphelion. Comets visible to the naked eye, and have been known since spend most of the time near aphelion far from the ancient times. They have a hazy, fuzzy appearance. sun, so that their ices remain frozen. -
The Hungaria Asteroids: Close Encounters and Impacts with Terrestrial Planets
Mem. S.A.It. Suppl. Vol. 26, 38 Memorie della c SAIt 2014 Supplementi The Hungaria Asteroids: close encounters and impacts with terrestrial planets M. A. Galiazzo, A. Bazso, and R. Dvorak Institute of Astronomy, University of Vienna, Turkenschanzstr.¨ 17, A-1180 Wien, Austria e-mail: [email protected] Abstract. The Hungaria asteroid family (Named after (434) Hungaria), which consists of more than 5000 members with semi-major axes between 1.78 and 2.03 AU and have in- clinations of the order of 20◦, is regarded as one source for Near-Earth Asteroids (NEAs). They are mainly perturbed by Jupiter and Mars, and are ejected because of mean motion and secular resonances with these planets and then become Mars-crossers; later they may even cross the orbits of Earth and Venus. We are interested to analyze the close encounters and possible impacts with these planets. For 200 selected objects which are on the edge of the group we integrated their orbits over 100 million years in a simplified model of the planetary system (Mars to Saturn) subject to only gravitational forces. We picked out a sam- ple of 11 objects (each with 50 clones) with large variations in semi-major axis and some of them achieve high inclinations and eccentricities in connection with mean motion and secular resonances which then leads to relatively high velocity impacts on Venus, Earth and Mars. We report all close encounters and impacts with the terrestrial planets and statistically determine the mean life and the orbital distribution of the NEAs of these Hungarias. -
Alactic Observer
alactic Observer G John J. McCarthy Observatory Volume 14, No. 2 February 2021 International Space Station transit of the Moon Composite image: Marc Polansky February Astronomy Calendar and Space Exploration Almanac Bel'kovich (Long 90° E) Hercules (L) and Atlas (R) Posidonius Taurus-Littrow Six-Day-Old Moon mosaic Apollo 17 captured with an antique telescope built by John Benjamin Dancer. Dancer is credited with being the first to photograph the Moon in Tranquility Base England in February 1852 Apollo 11 Apollo 11 and 17 landing sites are visible in the images, as well as Mare Nectaris, one of the older impact basins on Mare Nectaris the Moon Altai Scarp Photos: Bill Cloutier 1 John J. McCarthy Observatory In This Issue Page Out the Window on Your Left ........................................................................3 Valentine Dome ..............................................................................................4 Rocket Trivia ..................................................................................................5 Mars Time (Landing of Perseverance) ...........................................................7 Destination: Jezero Crater ...............................................................................9 Revisiting an Exoplanet Discovery ...............................................................11 Moon Rock in the White House....................................................................13 Solar Beaming Project ..................................................................................14 -
25 Years of Cosmic Microwave Background Research at Inpe
Proceedings of the Brazilian Decimetric Array Workshop São José dos Campos, Brazil - July 28 – August 1, 2008 25 YEARS OF COSMIC MICROWAVE BACKGROUND RESEARCH AT INPE Carlos Alexandre Wuensche and Thyrso Villela Divisão de Astrofísica - Instituto de Pesquisas Espaciais - INPE Av. dos Astronautas,1758 – 12201-970, São José dos Campos-SP, Brasil ABSTRACT This article is a report of 25 years of Cosmic Microwave Background activities at INPE. Starting from balloon flights to measure the dipole anisotropy caused by the Earth’s motion inside the CMB radiation field, whose radiometer was a prototype of the DMR radiometer on board COBE satellite, member of the group cross the 90s working both on CMB anisotropy and foreground measurements. In the 2000s, there was a shift to polarization measurements and to data analysis, mostly focusing on map cleaning, non-gaussianity studies and foreground characterization. INTRODUCTION The cosmic microwave background radiation (CMB) is one of the most important cosmological observables presently available to cosmologists. Its properties can unveil information, among others, about the inflationary period, the overall composition of the Universe ( Ω0), the existence of gravitational waves, the age of the Universe and other parameters related to the recombination and decoupling era (Hu and Dodelson, 2002). These observables are critical to understand the physical processes accounting for the formation and evolution of the Universe. The CMB is observed from a few GHz to a few hundreds of GHz. It also observed in various angular scales, varying from less than 1 arcmin to many degrees, each range of scales encoding information about specific physical processes from the early (or not so early) Universe. -
Alexandre Amorim -.:: GEOCITIES.Ws
Alexandre Amorim (org) 2 3 PREFÁCIO O Boletim Observe! é uma iniciativa da Coordenação de Observação Astronômica do Núcleo de Estudo e Observação Astronômica “José Brazilício de Souza” (NEOA-JBS). Durante a reunião administrativa do NEOA-JBS em maio de 2010 foi apresentada a edição de Junho de 2010 para apreciação dos demais coordenadores do Núcleo onde houve aprovação unânime em usar o Boletim Observe! como veículo de informação das atividades e, principalmente, observações astronômicas. O Boletim Observe! é publicado mensalmente em formato eletrônico ou impresso separadamente, prezando pela simplicidade das informações e encorajando os leitores a observar, registrar e publicar os eventos astronômicos. Desde a sua primeira edição o Boletim Observe! conta com a colaboração espontânea de diversos astrônomos amadores e profissionais. Toda edição do Observe! do mês de dezembro é publicado um índice dos artigos do respectivo ano. Porém, desde aquela edição de Junho de 2010 foram publicados centenas de artigos e faz-se necessário consultar assuntos que foram tratados nas edições anteriores do Observe! e seus respectivos autores. Para isso publicaremos anualmente esse Índice de Assuntos, permitindo a consulta rápida dos temas abordados. Florianópolis, 1º de dezembro de 2018 Alexandre Amorim Coordenação de Observação Astronômica do NEOA-JBS 4 Ano I (2010) Nº 1 – Junho 2010 Eclipse da Lua em 26 de junho de 2010 Amorim, A. Júpiter sem a Banda Equatorial Sul Amorim, A. Conjunção entre Júpiter e Urano Amorim, A. Causos do Avelino Alves, A. A. Quem foi Eugênia de Bessa? Amorim, A. Nº 2 – Julho 2010 Aprendendo a dimensionar as distâncias angulares no céu Neves, M. -
June 2020 PRAYAS4 IAS यास सनु हर े भ व य क
June 2020 PRAYAS4 IAS यास सनु हर े भवय क Current Affairs Special Issue MCQs [email protected] www.theprayasindia.com/upsc An initiative for UPSC Aspirants S o u r c e s The Hindu | Live Mint | The Economic Times | The Indian Express | PRS PIB | PRS | ET | Government & World Reports (NITI, Aayog, Budget WEF Economic Survey etc.) | Hindu Business Line | NCERTs | All standard reference books The Prayas ePathshala www.theprayasindia.com/e-pathshala/ June (Week 1) Index Prelims Mains National GS I 1. Rajya Sabha elections 2. BHIM App 1. COVID-19 exposes fault lines in peri- 3. Cyclone Nisarga urban areas 4. PM SVANidhi 2. COVID-19 and our new normal 5. Essential Commodities Act 6. Inner Line permit 7. Kolkata Port GS II 8. SWADES 9. Amery Ice Shelf 1. Military bonding beyond borders 10. World Environment Day 2020 2. COVID-19: Exclusion, isolation of 11. TULIP differently abled 12. Nagar Van Scheme 13. Van Dhan Scheme International 1. Travel Bubble 2. Antifa 3. Line of Actual Control 4. G-7 5. The National Guard 6. THAAD Defence System www.theprayasindia.com/e-pathshala [email protected] +91-7710013217 / 9892560176 The Prayas ePathshala www.theprayasindia.com/e-pathshala/ Prelims NATIONAL Rajya Sabha elections (Source: The Hindu ) Context: The elections to 18 Rajya Sabha seats that were deferred owing to the lockdown will be held on June 19. How elections are conducted in Rajya Sabha? The Rajya Sabha or the Upper House of Parliament is modeled after the House of Lords in the United Kingdom. The Rajya Sabha currently has 245 members, including 233 elected members and 12 nominated.