Transitional and Temporary Objects in the Jupiter Trojan Area
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(121514) 1999 UJ7: a Primitive, Slow-Rotating Martian Trojan G
A&A 618, A178 (2018) https://doi.org/10.1051/0004-6361/201732466 Astronomy & © ESO 2018 Astrophysics ? (121514) 1999 UJ7: A primitive, slow-rotating Martian Trojan G. Borisov1,2, A. A. Christou1, F. Colas3, S. Bagnulo1, A. Cellino4, and A. Dell’Oro5 1 Armagh Observatory and Planetarium, College Hill, Armagh BT61 9DG, Northern Ireland, UK e-mail: [email protected] 2 Institute of Astronomy and NAO, Bulgarian Academy of Sciences, 72, Tsarigradsko Chaussée Blvd., 1784 Sofia, Bulgaria 3 IMCCE, Observatoire de Paris, UPMC, CNRS UMR8028, 77 Av. Denfert-Rochereau, 75014 Paris, France 4 INAF – Osservatorio Astrofisico di Torino, via Osservatorio 20, 10025 Pino Torinese (TO), Italy 5 INAF – Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, 50125, Firenze, Italy Received 15 December 2017 / Accepted 7 August 2018 ABSTRACT Aims. The goal of this investigation is to determine the origin and surface composition of the asteroid (121514) 1999 UJ7, the only currently known L4 Martian Trojan asteroid. Methods. We have obtained visible reflectance spectra and photometry of 1999 UJ7 and compared the spectroscopic results with the spectra of a number of taxonomic classes and subclasses. A light curve was obtained and analysed to determine the asteroid spin state. Results. The visible spectrum of 1999 UJ7 exhibits a negative slope in the blue region and the presence of a wide and deep absorption feature centred around ∼0.65 µm. The overall morphology of the spectrum seems to suggest a C-complex taxonomy. The photometric behaviour is fairly complex. The light curve shows a primary period of 1.936 d, but this is derived using only a subset of the photometric data. -
Origin and Evolution of Trojan Asteroids 725
Marzari et al.: Origin and Evolution of Trojan Asteroids 725 Origin and Evolution of Trojan Asteroids F. Marzari University of Padova, Italy H. Scholl Observatoire de Nice, France C. Murray University of London, England C. Lagerkvist Uppsala Astronomical Observatory, Sweden The regions around the L4 and L5 Lagrangian points of Jupiter are populated by two large swarms of asteroids called the Trojans. They may be as numerous as the main-belt asteroids and their dynamics is peculiar, involving a 1:1 resonance with Jupiter. Their origin probably dates back to the formation of Jupiter: the Trojan precursors were planetesimals orbiting close to the growing planet. Different mechanisms, including the mass growth of Jupiter, collisional diffusion, and gas drag friction, contributed to the capture of planetesimals in stable Trojan orbits before the final dispersal. The subsequent evolution of Trojan asteroids is the outcome of the joint action of different physical processes involving dynamical diffusion and excitation and collisional evolution. As a result, the present population is possibly different in both orbital and size distribution from the primordial one. No other significant population of Trojan aster- oids have been found so far around other planets, apart from six Trojans of Mars, whose origin and evolution are probably very different from the Trojans of Jupiter. 1. INTRODUCTION originate from the collisional disruption and subsequent reaccumulation of larger primordial bodies. As of May 2001, about 1000 asteroids had been classi- A basic understanding of why asteroids can cluster in fied as Jupiter Trojans (http://cfa-www.harvard.edu/cfa/ps/ the orbit of Jupiter was developed more than a century lists/JupiterTrojans.html), some of which had only been ob- before the first Trojan asteroid was discovered. -
March 21–25, 2016
FORTY-SEVENTH LUNAR AND PLANETARY SCIENCE CONFERENCE PROGRAM OF TECHNICAL SESSIONS MARCH 21–25, 2016 The Woodlands Waterway Marriott Hotel and Convention Center The Woodlands, Texas INSTITUTIONAL SUPPORT Universities Space Research Association Lunar and Planetary Institute National Aeronautics and Space Administration CONFERENCE CO-CHAIRS Stephen Mackwell, Lunar and Planetary Institute Eileen Stansbery, NASA Johnson Space Center PROGRAM COMMITTEE CHAIRS David Draper, NASA Johnson Space Center Walter Kiefer, Lunar and Planetary Institute PROGRAM COMMITTEE P. Doug Archer, NASA Johnson Space Center Nicolas LeCorvec, Lunar and Planetary Institute Katherine Bermingham, University of Maryland Yo Matsubara, Smithsonian Institute Janice Bishop, SETI and NASA Ames Research Center Francis McCubbin, NASA Johnson Space Center Jeremy Boyce, University of California, Los Angeles Andrew Needham, Carnegie Institution of Washington Lisa Danielson, NASA Johnson Space Center Lan-Anh Nguyen, NASA Johnson Space Center Deepak Dhingra, University of Idaho Paul Niles, NASA Johnson Space Center Stephen Elardo, Carnegie Institution of Washington Dorothy Oehler, NASA Johnson Space Center Marc Fries, NASA Johnson Space Center D. Alex Patthoff, Jet Propulsion Laboratory Cyrena Goodrich, Lunar and Planetary Institute Elizabeth Rampe, Aerodyne Industries, Jacobs JETS at John Gruener, NASA Johnson Space Center NASA Johnson Space Center Justin Hagerty, U.S. Geological Survey Carol Raymond, Jet Propulsion Laboratory Lindsay Hays, Jet Propulsion Laboratory Paul Schenk, -
Astrocladistics of the Jovian Trojan Swarms
MNRAS 000,1–26 (2020) Preprint 23 March 2021 Compiled using MNRAS LATEX style file v3.0 Astrocladistics of the Jovian Trojan Swarms Timothy R. Holt,1,2¢ Jonathan Horner,1 David Nesvorný,2 Rachel King,1 Marcel Popescu,3 Brad D. Carter,1 and Christopher C. E. Tylor,1 1Centre for Astrophysics, University of Southern Queensland, Toowoomba, QLD, Australia 2Department of Space Studies, Southwest Research Institute, Boulder, CO. USA. 3Astronomical Institute of the Romanian Academy, Bucharest, Romania. Accepted XXX. Received YYY; in original form ZZZ ABSTRACT The Jovian Trojans are two swarms of small objects that share Jupiter’s orbit, clustered around the leading and trailing Lagrange points, L4 and L5. In this work, we investigate the Jovian Trojan population using the technique of astrocladistics, an adaptation of the ‘tree of life’ approach used in biology. We combine colour data from WISE, SDSS, Gaia DR2 and MOVIS surveys with knowledge of the physical and orbital characteristics of the Trojans, to generate a classification tree composed of clans with distinctive characteristics. We identify 48 clans, indicating groups of objects that possibly share a common origin. Amongst these are several that contain members of the known collisional families, though our work identifies subtleties in that classification that bear future investigation. Our clans are often broken into subclans, and most can be grouped into 10 superclans, reflecting the hierarchical nature of the population. Outcomes from this project include the identification of several high priority objects for additional observations and as well as providing context for the objects to be visited by the forthcoming Lucy mission. -
Aas 14-267 Design of End-To-End Trojan Asteroid
AAS 14-267 DESIGN OF END-TO-END TROJAN ASTEROID RENDEZVOUS TOURS INCORPORATING POTENTIAL SCIENTIFIC VALUE Jeffrey Stuart,∗ Kathleen Howell,y and Roby Wilsonz The Sun-Jupiter Trojan asteroids are celestial bodies of great scientific interest as well as potential natural assets offering mineral resources for long-term human exploration of the solar system. Previous investigations have addressed the auto- mated design of tours within the asteroid swarm and the transition of prospective tours to higher-fidelity, end-to-end trajectories. The current development incorpo- rates the route-finding Ant Colony Optimization (ACO) algorithm into the auto- mated tour generation procedure. Furthermore, the potential scientific merit of the target asteroids is incorporated such that encounters with higher value asteroids are preferentially incorporated during sequence creation. INTRODUCTION Near Earth Objects (NEOs) are currently under consideration for manned sample return mis- sions,1 while a recent NASA feasibility assessment concludes that a mission to the Trojan asteroids can be accomplished at a projected cost of less than $900M in fiscal year 2015 dollars.2 Tour concepts within asteroid swarms allow for a broad sampling of interesting target bodies either for scientific investigation or as potential resources to support deep-space human missions. However, the multitude of asteroids within the swarms necessitates the use of automated design algorithms if a large number of potential mission options are to be surveyed. Previously, a process to automatically and rapidly generate sample tours within the Sun-Jupiter L4 Trojan asteroid swarm with a mini- mum of human interaction has been developed.3 This scheme also enables the automated transition of tours of interest into fully optimized, end-to-end trajectories using a variety of electrical power sources.4,5 This investigation extends the automated algorithm to use ant colony optimization, a heuristic search algorithm, while simultaneously incorporating a relative ‘scientific importance’ ranking into tour construction and analysis. -
A Low Density of 0.8 G Cm-3 for the Trojan Binary Asteroid 617 Patroclus
Publisher: NPG; Journal: Nature:Nature; Article Type: Physics letter DOI: 10.1038/nature04350 A low density of 0.8 g cm−3 for the Trojan binary asteroid 617 Patroclus Franck Marchis1, Daniel Hestroffer2, Pascal Descamps2, Jérôme Berthier2, Antonin H. Bouchez3, Randall D. Campbell3, Jason C. Y. Chin3, Marcos A. van Dam3, Scott K. Hartman3, Erik M. Johansson3, Robert E. Lafon3, David Le Mignant3, Imke de Pater1, Paul J. Stomski3, Doug M. Summers3, Frederic Vachier2, Peter L. Wizinovich3 & Michael H. Wong1 1Department of Astronomy, University of California, 601 Campbell Hall, Berkeley, California 94720, USA. 2Institut de Mécanique Céleste et de Calculs des Éphémérides, UMR CNRS 8028, Observatoire de Paris, 77 Avenue Denfert-Rochereau, F-75014 Paris, France. 3W. M. Keck Observatory, 65-1120 Mamalahoa Highway, Kamuela, Hawaii 96743, USA. The Trojan population consists of two swarms of asteroids following the same orbit as Jupiter and located at the L4 and L5 stable Lagrange points of the Jupiter–Sun system (leading and following Jupiter by 60°). The asteroid 617 Patroclus is the only known binary Trojan1. The orbit of this double system was hitherto unknown. Here we report that the components, separated by 680 km, move around the system’s centre of mass, describing a roughly circular orbit. Using this orbital information, combined with thermal measurements to estimate +0.2 −3 the size of the components, we derive a very low density of 0.8 −0.1 g cm . The components of 617 Patroclus are therefore very porous or composed mostly of water ice, suggesting that they could have been formed in the outer part of the Solar System2. -
Trajectory Design of the Lucy Mission to Explore the Diversity of the Jupiter Trojans
70th International Astronautical Congress, Washington, DC. This material is declared a work of the U.S. Government and is not subject to copyright protection in the United States. IAC–2019–C1.2.11 Trajectory Design of the Lucy Mission to Explore the Diversity of the Jupiter Trojans Jacob A. Englander Aerospace Engineer, Navigation and Mission Design Branch, NASA Goddard Space Flight Center Kevin Berry Lucy Flight Dynamics Lead, Navigation and Mission Design Branch, NASA Goddard Space Flight Center Brian Sutter Totally Awesome Trajectory Genius, Lockheed Martin Space Systems, Littleton, CO Dale Stanbridge Lucy Navigation Team Chief, KinetX Aerospace, Simi Valley, CA Donald H. Ellison Aerospace Engineer, Navigation and Mission Design Branch, NASA Goddard Space Flight Center Ken Williams Flight Director, Space Navigation and Flight Dynamics Practice, KinetX Aerospace, Simi Valley, California James McAdams Aerospace Engineer, Space Navigation and Flight Dynamics Practice, KinetX Aerospace, Simi Valley, California Jeremy M. Knittel Aerospace Engineer, Space Navigation and Flight Dynamics Practice, KinetX Aerospace, Simi Valley, California Chelsea Welch Fantastically Awesome Deputy Trajectory Genius, Lockheed Martin Space Systems, Littleton, CO Hal Levison Principle Investigator, Lucy mission, Southwest Research Institute, Boulder, CO Lucy, NASA’s next Discovery-class mission, will explore the diversity of the Jupiter Trojan asteroids. The Jupiter Trojans are thought to be remnants of the early solar system that were scattered inward when the gas giants migrated to their current positions as described in the Nice model. There are two stable subpopulations, or “swarms,” captured at the Sun-Jupiter L4 and L5 regions. These objects are the most accessible samples of what the outer solar system may have originally looked like. -
Modeling the Evection Resonance for Trojan Satellites: Application to the Saturn System C
A&A 620, A90 (2018) https://doi.org/10.1051/0004-6361/201833735 Astronomy & © ESO 2018 Astrophysics Modeling the evection resonance for Trojan satellites: application to the Saturn system C. A. Giuppone1, F. Roig2, and X. Saad-Olivera2 1 Universidad Nacional de Córdoba, Observatorio Astronómico, IATE, Laprida 854, 5000 Córdoba, Argentina e-mail: [email protected] 2 Observatório Nacional, Rio de Janeiro, 20921-400, RJ, Brazil Received 27 June 2018 / Accepted 6 September 2018 ABSTRACT Context. The stability of satellites in the solar system is affected by the so-called evection resonance. The moons of Saturn, in par- ticular, exhibit a complex dynamical architecture in which co-orbital configurations occur, especially close to the planet where this resonance is present. Aims. We address the dynamics of the evection resonance, with particular focus on the Saturn system, and compare the known behav- ior of the resonance for a single moon with that of a pair of moons in co-orbital Trojan configuration. Methods. We developed an analytic expansion of the averaged Hamiltonian of a Trojan pair of bodies, including the perturbation from a distant massive body. The analysis of the corresponding equilibrium points was restricted to the asymmetric apsidal corotation solution of the co-orbital dynamics. We also performed numerical N-body simulations to construct dynamical maps of the stability of the evection resonance in the Saturn system, and to study the effects of this resonance under the migration of Trojan moons caused by tidal dissipation. Results. The structure of the phase space of the evection resonance for Trojan satellites is similar to that of a single satellite, differing in that the libration centers are displaced from their standard positions by an angle that depends on the periastron difference $2 − $1 and on the mass ratio m2=m1 of the Trojan pair. -
Kuiper Belt and Comets: an Observational Perspective
Kuiper Belt and Comets: An Observational Perspective David Jewitt1 1. Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 [email protected] Note to the Reader These notes outline a series of lectures given at the Saas Fee Winter School held in Murren, Switzerland, in March 2005. As I see it, the main aim of the Winter School is to communicate (especially) with young people in order to inflame their interests in science and to encourage them to see ways in which they can contribute and maybe do a better job than we have done so far. With this in mind, I have written up my lectures in a less than formal but hopefully informative and entertaining style, and I have taken a few detours to discuss subjects that I think are important but which are usually glossed-over in the scientific literature. 1 Preamble Almost exactly 400 years ago, planetary astronomy kick-started the era of modern science, with a series of remarkable discoveries by Galileo concerning the surfaces of the Moon and Sun, the phases of Venus, and the existence and motions of Jupiter’s large satellites. By the early 20th century, the fo- cus of astronomical attention had turned to objects at larger distances, and to questions of galactic structure and cosmological interest. At the start of the 21st century, the tide has turned again. The study of the Solar system, particularly of its newly discovered outer parts, is one of the hottest topics in modern astrophysics with great potential for revealing fundamental clues about the origin of planets and even the emergence of life. -
The Decam View of the Solar System
The DECam view of the Solar System David E. Trilling (NAU) Why is DECam interesting for Solar System science? Why is DECam interesting for Solar System science? It’s all about the etendue! Why is DECam interesting for Solar System science? It’s not about the south, or the filters, or anything else (to first order). What is DECam? • 3 deg2 imager for NOAO/CTIO 4m • R~24 in ~60 sec • R~25 in ~6 min • R~26 in ~1 hr • R~27 in ~1 night What is the Solar System? What is the Solar System? Some current Solar System topics • Near Earth Objects (NEOs) • Trojan asteroids (Earth, Mars, Neptune) • Irregular satellites of giant planets • Kuiper Belt Objects (KBOs) • … plus many others (comets? 1000s of asteroids? you name it) Near Earth Objects (NEOs) Near Earth Objects (NEOs) • What is the population of NEOs? – Size distribution, orbital distribution – Evolution of near-Earth space • What is the impact risk? Both are addressed by a WIDE, DEEP search NEO search comparison NEO surveys to V=18 NEO search comparison NEO surveys to V=21 NEO search comparison NEO surveys to V=24 NEO search comparison NEO surveys to V=24 60 sec NEO search • Discover many 100s of NEOs in a single night. • A few night run gives you 10% percent of all known NEOs. • More than 80% of DECam NEO discoveries will be fainter than any other survey would discover • Capability to discover NEOs smaller than 50 m Trojan asteroids Trojan asteroids Trojan asteroids • Orbit +/-60 degrees from their planet • Stable over 4.5 billion years • Probe the early Solar System • Jupiter, Neptune, Mars … • … and now Earth Trojan asteroids • Thousands of known Jupiter Trojans • 8 known Neptune Trojans • ~4 known Mars Trojans • 1(?) known Earth Trojan • To use Trojans as probes of Solar System history, you need a DEEP, WIDE search Trojan asteroids • Biggest survey for Neptune Trojans to date(Sheppard & Trujillo 2010) covered 49 deg2 to R~25.7 over six years. -
The Orbit of 2010 TK7. Possible Regions of Stability for Other Earth Trojan Asteroids
Astronomy & Astrophysics manuscript no. ForarXiv October 15, 2018 (DOI: will be inserted by hand later) The orbit of 2010 TK7. Possible regions of stability for other Earth Trojan asteroids R. Dvorak1, C. Lhotka2, L. Zhou3 1 Universit¨atssternwarte Wien, T¨urkenschanzstr. 17, A-1180 Wien, Austria, 2 D´epartment de Math´ematique (naXys), Rempart de la Vierge, 8, B-5000 Namur, Belgium, 3 Department of Astronomy & Key Laboratory of Modern Astronomy and Astrophysics in Ministry of Education, Nanjing University, Nanjing 210093, China Received; accepted Abstract. Recently the first Earth Trojan has been observed (Mainzer et al., ApJ 731) and found to be on an interesting orbit close to the Lagrange point L4 (Connors et al., Nature 475). In the present study we therefore perform a detailed investigation on the stability of its orbit and moreover extend the study to give an idea of the probability to find additional Earth–Trojans. Our results are derived using different approaches: a) we derive an analytical mapping in the spatial elliptic restricted three–body problem to find the phase space structure of the dynamical problem. We explore the stability of the asteroid in the context of the phase space geometry, including the indirect influence of the additional planets of our Solar system. b) We use precise numerical methods to integrate the orbit forward and backward in time in different dynamical models. Based on a set of 400 clone orbits we derive the probability of capture and escape of the Earth Trojan asteroids 2010 TK7. c) To this end we perform an extensive numerical investigation of the stability region of the Earth’s Lagrangian points. -
Arxiv:1710.05000V3 [Astro-Ph.SR] 30 Jan 2018 Ine Available Data to Determine the Brightness Variations Over the Last Decade
Draft version November 12, 2018 Typeset using LATEX twocolumn style in AASTeX62 The year-long flux variations in Boyajian's star are asymmetric or aperiodic Michael Hippke1 and Daniel Angerhausen2, 3 1Sonneberg Observatory, Sternwartestr. 32, 96515 Sonneberg, Germany 2Center for Space and Habitability, University of Bern, Hochschulstrasse 6, 3012 Bern, Switzerland 3Blue Marble Space Institute of Science, 1001 4th ave, Suite 3201 Seattle, Washington 98154 USA ABSTRACT We combine and calibrate publicly available data for Boyajian's star including photometry from ASAS (SN, V, I), Kepler, Gaia, SuperWASP, and citizen scientist observations (AAVSO, HAO and Burke-Gaffney). Precise (mmag) photometry covers the years 2006 − 2017. We show that the year-long flux variations with an amplitude of ≈ 4 % can not be explained with cyclical sym- metric or asymmetric models with periods shorter than ten years. If the dips are transits, their period must exceed ten years, or their structure must evolve significantly during each 4-year long cycle. 1. INTRODUCTION 11.89 Boyajians Star (KIC 8462852) is a mysterious ob- 11.91 ject which showed asymmetric, aperiodic day-long deep (20 %) dips in brightness during Kepler's 2009 − 2013 11.93 mission (Boyajian et al. 2016). The mystery deepened when Schaefer(2016) claimed a dimming of the star dur- 11.95 ing 1890 − 1990 based on historical plates, and Mon- tet & Simon(2016) showed that the dimming continued 11.97 during Kepler's mission. These results have been inter- preted that the brightness of Boyajians Star is monoton- mag) (calibrated Brightness 11.99 ically decreasing with time. Although the century-long dimming has been challenged in re-analyses (Hippke 12.01 et al.