WorldWideScience

Sample records for asteroids

  1. ASTEROIDS

    Directory of Open Access Journals (Sweden)

    Željko Andreić

    2016-02-01

    Full Text Available Asteroids are the largest minor bodies in the Solar System. Nowadays they are in the research focus due to several facts about them: first, a subclass of asteroids can collide with Earth, and consequences of such a collision are dramatic. Second, they are now seen as source of materials that are becoming scarce on Earth, and they will be needed in future space constructions anyway. Third, they are holding clues about the origin and evolution of the Solar System. In this article, a short overview of current knowledge about asteroids is presented. Last, but not least, as several Croatian scientists were recently honored by naming an asteroid after them, a short overview of the naming process is given.

  2. ASTEROIDS

    OpenAIRE

    Željko Andreić

    2016-01-01

    Asteroids are the largest minor bodies in the Solar System. Nowadays they are in the research focus due to several facts about them: first, a subclass of asteroids can collide with Earth, and consequences of such a collision are dramatic. Second, they are now seen as source of materials that are becoming scarce on Earth, and they will be needed in future space constructions anyway. Third, they are holding clues about the origin and evolution of the Solar System. In this article, a short overv...

  3. Asteroid mining

    Science.gov (United States)

    Gertsch, Richard E.

    1992-01-01

    The earliest studies of asteroid mining proposed retrieving a main belt asteroid. Because of the very long travel times to the main asteroid belt, attention has shifted to the asteroids whose orbits bring them fairly close to the Earth. In these schemes, the asteroids would be bagged and then processed during the return trip, with the asteroid itself providing the reaction mass to propel the mission homeward. A mission to one of these near-Earth asteroids would be shorter, involve less weight, and require a somewhat lower change in velocity. Since these asteroids apparently contain a wide range of potentially useful materials, our study group considered only them. The topics covered include asteroid materials and properties, asteroid mission selection, manned versus automated missions, mining in zero gravity, and a conceptual mining method.

  4. Asteroid Redirect

    OpenAIRE

    De Aquino, Fran

    2017-01-01

    Asteroids are a great threat to mankind. Here we will show that it is possible to redirect them from their trajectories by means of a strong gravitational repulsion, produced by the gravitational interaction between the asteroid and a Gravitational Spacecraft positioned close to the asteroid.

  5. Asteroid Photometry

    CERN Document Server

    Li, Jian-Yang; Buratti, Bonnie J; Takir, Driss; Clark, Beth Ellen

    2015-01-01

    Asteroid photometry has three major applications: providing clues about asteroid surface physical properties and compositions, facilitating photometric corrections, and helping design and plan ground-based and spacecraft observations. The most significant advances in asteroid photometry in the past decade were driven by spacecraft observations that collected spatially resolved imaging and spectroscopy data. In the mean time, laboratory measurements and theoretical developments are revealing controversies regarding the physical interpretations of models and model parameter values. We will review the new developments in asteroid photometry that have occurred over the past decade in the three complementary areas of observations, laboratory work, and theory. Finally we will summarize and discuss the implications of recent findings.

  6. Asteroid taxonomy

    Science.gov (United States)

    Tholen, David J.; Barucci, M. Antonietta

    1989-01-01

    The spectral reflectivity of asteroid surfaces over the wavelength range of 0.3 to 1.1 micron can be used to classify these objects into several broad groups with similar spectral characteristics. The three most recently developed taxonomies group the asteroids into 9, 11, or 14 different clases, depending on the technique used to perform the analysis. The distribution of the taxonomic classes shows that darker and redder objects become more dominant at larger heliocentric distances, while the rare asteroid types are found more frequently among the small objects of the planet-crossing population.

  7. Asteroids IV

    Science.gov (United States)

    Michel, Patrick; DeMeo, Francesca E.; Bottke, William F.

    Asteroids are fascinating worlds. Considered the building blocks of our planets, many of the authors of this book have devoted their scientific careers to exploring them with the tools of our trade: ground- and spacebased observations, in situ space missions, and studies that run the gamut from theoretical modeling efforts to laboratory work. Like fossils for paleontologists, or DNA for geneticists, they allow us to construct a veritable time machine and provide us with tantalizing glimpses of the earliest nature of our solar system. By investigating them, we can probe what our home system was like before life or even the planets existed. The origin and evolution of life on our planet is also intertwined with asteroids in a different way. It is believed that impacts on the primordial Earth may have delivered the basic components for life, with biology favoring attributes that could more easily survive the aftermath of such energetic events. In this fashion, asteroids may have banished many probable avenues for life to relative obscurity. Similarly, they may have also prevented our biosphere from becoming more complex until more recent eras. The full tale of asteroid impacts on the history of our world, and how human life managed to emerge from myriad possibilities, has yet to be fully told. The hazard posed by asteroid impacts to our civilization is low but singular. The design of efficient mitigation strategies strongly relies on asteroid detection by our ground- and spacebased surveys as well as knowledge of their physical properties. A more positive motivation for asteroid discovery is that the proximity of some asteroids to Earth may allow future astronauts to harvest their water and rare mineral resources for use in exploration. A key goal of asteroid science is therefore to learn how humans and robotic probes can interact with asteroids (and extract their materials) in an efficient way. We expect that these adventures may be commonplace in the future

  8. Asteroid structure

    Science.gov (United States)

    Asphaug, E.

    2014-07-01

    Even before the first space missions to asteroids, in the mid-1990s, it was known that asteroids have weird structures. Photometry indicated complicated shapes, and the pioneering radar investigations by Ostro and colleagues followed by adaptive optics campaigns and flybys showed odd binary forms, and confirmed the common presence of satellites, and indications of highly varying surface roughness. Some asteroids turned out to be dominated by a single major cratering event, while others showed no evidence of a major crater, or perhaps for global crater erasure. The first space mission to orbit an asteroid, NEAR, found a mixture of heavily cratered terrains and geomorphically active 'ponds', and indicated evidence for global seismicity from impact. The next mission to orbit an asteroid, Hayabusa, found what most agree is a rubble pile, with no major craters and an absence of fines. There is to date no direct evidence of asteroid interior geology, other than measurements of bulk density, and inferences made for mass distribution asymmetry based on dynamics, and inferences based on surface lineaments. Interpolating from the surface to the interior is always risky and usually wrong, but of course the answer is important since we are someday destined to require this knowledge in order to divert a hazardous asteroid from impact with the Earth. Even considering the near-subsurface, here we remain as ignorant as we were about the Moon in the early 1960s, whether the surface will swallow us up in dust, or will provide secure landing and anchoring points. Laboratory experimentation in close to zero-G is still in its early stages. Adventures such as mining and colonization will surely have to wait until we better know these things. How do we get from here to there? I will focus on 3 areas of progress: (1) asteroid cratering seismology, where we use the surface craters to understand what is going on inside; (2) numerical modeling of collisions, which predicts the internal

  9. Small asteroid system evolution

    OpenAIRE

    Jacobson, Seth A.

    2014-01-01

    Observations with radar, photometric and direct imaging techniques have discovered that multiple asteroid systems can be divided clearly into a handful of different morphologies, and recently, the discovery of small unbound asteroid systems called asteroid pairs have revolutionized the study of small asteroid systems. Simultaneously, new theoretical advances have demonstrated that solar radiation dictates the evolution of small asteroids with strong implications for asteroid internal structur...

  10. Search for Asteroid-Asteroid Encounters

    Directory of Open Access Journals (Sweden)

    Luis A. Mammana

    2001-01-01

    Full Text Available Earlier studies about asteroids did not consider mutual interactions since they assume a negligible asteroid mass. In 1966 Hertz took into account for the first time the gravitational effects produced by an asteroid on another for mass determination. This gravitational action becomes relevant for enough effective encounters. The most efficient gravitational interaction is that produced in a large time interval and for small distances. For each particular caseful it is relevant to perform a care analysis in order to determinate the feasibility in the mass determination and improved orbital elements. In the present paper we performed a search of asteroid-asteroid encounters occurred in the twenty century for the first 3000 numbered asteroids . Of all encounters we have selected only those asteroid pairs in which one of the asteroids has a diameter larger than 200 km and the other one (the smaller an observational interval of at least ten years.

  11. Asteroid Mining and Prospecting

    OpenAIRE

    Esty, Thomas

    2013-01-01

    There has been a recent increase in interest in the idea of mining asteroids, as seen from the founding of multiple companies who seek to make this science fiction idea science fact. We analyzed a number of prior papers on asteroids to make an estimate as to whether mining asteroids is within the realm of possibility. Existing information on asteroid number, composition, and orbit from past research was synthesized with a new analysis using binomial statistics of the number of probes that wou...

  12. Asteroid thermophysical modeling

    CERN Document Server

    Delbo, Marco; Emery, Joshua P; Rozitis, Ben; Capria, Maria Teresa

    2015-01-01

    The field of asteroid thermophysical modeling has experienced an extraordinary growth in the last ten years, as new thermal infrared data became available for hundreds of thousands of asteroids. The infrared emission of asteroids depends on the body's size, shape, albedo, thermal inertia, roughness and rotational properties. These parameters can therefore be derived by thermophysical modeling of infrared data. Thermophysical modeling led to asteroid size estimates that were confirmed at the few-percent level by later spacecraft visits. We discuss how instrumentation advances now allow mid-infrared interferometric observations as well as high-accuracy spectro-photometry, posing their own set of thermal-modeling challenges.We present major breakthroughs achieved in studies of the thermal inertia, a sensitive indicator for the nature of asteroids soils, allowing us, for instance, to determine the grain size of asteroidal regoliths. Thermal inertia also governs non-gravitational effects on asteroid orbits, requir...

  13. Asteroid exploration and utilization

    Science.gov (United States)

    Radovich, Brian M.; Carlson, Alan E.; Date, Medha D.; Duarte, Manny G.; Erian, Neil F.; Gafka, George K.; Kappler, Peter H.; Patano, Scott J.; Perez, Martin; Ponce, Edgar

    1992-01-01

    The Earth is nearing depletion of its natural resources at a time when human beings are rapidly expanding the frontiers of space. The resources possessed by asteroids have enormous potential for aiding and enhancing human space exploration as well as life on Earth. Project STONER (Systematic Transfer of Near Earth Resources) is based on mining an asteroid and transporting raw materials back to Earth. The asteroid explorer/sample return mission is designed in the context of both scenarios and is the first phase of a long range plan for humans to utilize asteroid resources. Project STONER is divided into two parts: asteroid selection and explorer spacecraft design. The spacecraft design team is responsible for the selection and integration of the subsystems: GNC, communications, automation, propulsion, power, structures, thermal systems, scientific instruments, and mechanisms used on the surface to retrieve and store asteroid regolith. The sample return mission scenario consists of eight primary phases that are critical to the mission.

  14. Applied Astronomy: Asteroid Prospecting

    Science.gov (United States)

    Elvis, M.

    2013-09-01

    In the age of asteroid mining the ability to find promising ore-bearing bodies will be valuable. This will give rise to a new discipline- "Applied Astronomy". Just as most geologists work in industry, not in academia, the same will be true of astronomers. Just how rare or common ore-rich asteroids are likely to be, and the skills needed to assay their value, are discussed here, with an emphasis on remote - telescopic - methods. Also considered are the resources needed to conduct extensive surveys of asteroids for prospecting purposes, and the cost and timescale involved. The longer-term need for applied astronomers is also covered.

  15. Near-Sun asteroids

    Science.gov (United States)

    Emel'yanenko, V. V.

    2017-01-01

    As follows from dynamical studies, in the course of evolution, most near-Earth objects reach orbits with small perihelion distances. Changes of the asteroids in the vicinity of the Sun should play a key role in forming the physical properties, size distribution, and dynamical features of the near-Earth objects. Only seven of the discovered asteroids are currently moving along orbits with perihelion distances q orbits farther from the Sun. In this study, we found asteroids that have been recently orbiting with perihelion distances q orbits for hundreds to tens of thousands of years. To carry out astrophysical observations of such objects is a high priority.

  16. Space weathering of asteroids

    CERN Document Server

    Shestopalov, D I; Cloutis, E A

    2012-01-01

    Analysis of laboratory experiments simulating space weathering optical effects on atmosphereless planetary bodies reveals that the time needed to alter the spectrum of an ordinary chondrite meteorite to resemble the overall spectral shape and slope of an S-type asteroid is about ~ 0.1 Myr. The time required to reduce the visible albedo of samples to ~ 0.05 is ~ 1 Myr. Since both these timescales are much less than the average collisional lifetime of asteroids larger than several kilometers in size, numerous low-albedo asteroids having reddish spectra with subdued absorption bands should be observed instead of an S-type dominated population. It is not the case because asteroid surfaces cannot be considered as undisturbed, unlike laboratory samples. We have estimated the number of collisions occurring in the time of 105 yr between asteroids and projectiles of various sizes and show that impact-activated motions of regolith particles counteract the progress of optical maturation of asteroid surfaces. Continual r...

  17. Asteroids - NeoWs API

    Data.gov (United States)

    National Aeronautics and Space Administration — NeoWs (Near Earth Object Web Service) is a RESTful web service for near earth Asteroid information. With NeoWs a user can: search for Asteroids based on their...

  18. The Asteroid Impact Mission

    Science.gov (United States)

    Carnelli, Ian; Galvez, Andres; Mellab, Karim

    2016-04-01

    The Asteroid Impact Mission (AIM) is a small and innovative mission of opportunity, currently under study at ESA, intending to demonstrate new technologies for future deep-space missions while addressing planetary defense objectives and performing for the first time detailed investigations of a binary asteroid system. It leverages on a unique opportunity provided by asteroid 65803 Didymos, set for an Earth close-encounter in October 2022, to achieve a fast mission return in only two years after launch in October/November 2020. AIM is also ESA's contribution to an international cooperation between ESA and NASA called Asteroid Impact Deflection Assessment (AIDA), consisting of two mission elements: the NASA Double Asteroid Redirection Test (DART) mission and the AIM rendezvous spacecraft. The primary goals of AIDA are to test our ability to perform a spacecraft impact on a near-Earth asteroid and to measure and characterize the deflection caused by the impact. The two mission components of AIDA, DART and AIM, are each independently valuable but when combined they provide a greatly increased scientific return. The DART hypervelocity impact on the secondary asteroid will alter the binary orbit period, which will also be measured by means of lightcurves observations from Earth-based telescopes. AIM instead will perform before and after detailed characterization shedding light on the dependence of the momentum transfer on the asteroid's bulk density, porosity, surface and internal properties. AIM will gather data describing the fragmentation and restructuring processes as well as the ejection of material, and relate them to parameters that can only be available from ground-based observations. Collisional events are of great importance in the formation and evolution of planetary systems, own Solar System and planetary rings. The AIDA scenario will provide a unique opportunity to observe a collision event directly in space, and simultaneously from ground-based optical and

  19. 2015 Barcelona Asteroid Day

    CERN Document Server

    Gritsevich, Maria; Palme, Herbert

    2017-01-01

    This volume is a compilation of the research presented at the International Asteroid Day workshop which was celebrated at Barcelona on June 30th, 2015. The proceedings discuss the beginning of a new era in the study and exploration of the solar system’s minor bodies. International Asteroid Day commemorates the Tunguska event of June 30th, 1908. The workshop’s goal was to promote the importance of dealing proactively with impact hazards from space. Multidisciplinary experts contributed to this discussion by describing the nature of comets and asteroids along with their offspring, meteoroids. New missions to return material samples of asteroids back to Earth such as Osiris-REx and Hayabusa 2, as well as projects like AIM and DART which will test impact deflection techniques for Potentially Hazardous Asteroids encounters were also covered. The proceedings include both an outreach level to popularize impact hazards and a scientific character which covers the latest knowledge on these topics, as well as offeri...

  20. Geography of the asteroid belt

    Science.gov (United States)

    Zellner, B. H.

    1978-01-01

    The CSM classification serves as the starting point on the geography of the asteroid belt. Raw data on asteroid types are corrected for observational biases (against dark objects, for instance) to derive the distribution of types throughout the belt. Recent work on family members indicates that dynamical families have a true physical relationship, presumably indicating common origin in the breakup of a parent asteroid.

  1. The Active Asteroids

    CERN Document Server

    Jewitt, Dave

    2011-01-01

    Some asteroids eject dust, unexpectedly producing transient, comet-like comae and tails. First ascribed to the sublimation of near-surface water ice, mass losing asteroids (also called "main-belt comets") can in fact be driven by a surprising diversity of mechanisms. In this paper, we consider eleven dynamical asteroids losing mass, in nine of which the ejected material is spatially resolved. We address mechanisms for producing mass loss including rotational instability, impact ejection, electrostatic repulsion, radiation pressure sweeping, dehydration stresses and thermal fracture, in addition to the sublimation of ice. In two objects (133P and 238P) the repetitive nature of the observed activity leaves ice sublimation as the only reasonable explanation while, in a third ((596) Scheila), a recent impact is the cause. Another impact may account for activity in P/2010 A2 but this tiny object can also be explained as having shed mass after reaching rotational instability. Mass loss from (3200) Phaethon is proba...

  2. Manuel's asteroid disruption technique.

    Science.gov (United States)

    John, Manuel; Ipe, Abraham; Jacob, Ivan

    2015-06-01

    A seventy-year-old male presented with dense asteroid hyalosis in both eyes. He had undergone cataract extraction in one eye 3 years ago, and the other eye had immature cataract. Both the autorefractor and dilated streak retinoscopy did not give readings and subjective visual improvement could not be achieved. Immediately following YAG posterior capsulotomy and anterior vitreous asteroid disruption, the vision improved to 20/20 with recordable auto refractor and streak retinoscopy values. Our initial experience indicates that the treatment is simple, safe and effective but needs controlled and prospective studies to confirm its long-term safety.

  3. Asteroid Control and Resource Utilization

    Science.gov (United States)

    Paterson, G.; Radice, G.; Sanchez, J.-P.

    Asteroids are materials rich small solar system bodies which are prime candidates for rendezvous and mining. Up until now much attention has been focused on methods of destroying or deflecting potentially hazardous asteroids from colliding with the Earth. Recently however the concept of asteroid capture has been suggested whereby the asteroid is returned to an orbit close to the Earth before mining can begin. This paper aims to provide a comprehensive introduction to the field for new researchers and to put forward a number of novel strategies for asteroid control.

  4. Asteroid science by Gaia

    Science.gov (United States)

    Muinonen, Karri; Cellino, Alberto; Dell Oro, Aldo; Tanga, Paolo; Delbo, Marco; Mignard, Francois; Thuillot, William; Berthier, Jerome; Carry, Benoit; Hestroffer, Daniel; Granvik, Mikael; Fedorets, Grigori

    2016-07-01

    Since the start of its regular observing program in summer 2014, the Gaia mission has carried out systematic photometric, spectrometric, and astrometric observations of asteroids. In total, the unique capabilities of Gaia allow for the collection of an extensive and homogeneous data set of some 350,000 asteroids down to the limiting magnitude of G = 20.7 mag. The Gaia performance remains excellent over the entire available brightness range. Starting from 2003, a working group of European asteroid scientists has explored the main capabilities of the mission, defining the expected scientific impact on Solar System science. These results have served as a basis for developing the Gaia data reduction pipeline, within the framework of the Data Processing and Analysis Consortium (DPAC). We describe the distribution of the existing and forecoming Gaia observations in space and time for different categories of objects. We illustrate the peculiar properties of each single observation, as these properties will affect the subsequent exploitation of the mission data. We will review the expected performances of Gaia, basically as a function of magnitude and proper motion of the sources. We will further focus on the areas that will benefit from complementary observational campaigns to improve the scientific return of the mission, and on the involvement of the planetary science community as a whole in the exploitation of the Gaia survey. We will thus describe the current and future opportunities for ground-based observers and forthcoming changes brought by Gaia in some observational approaches, such as stellar occultations by transneptunian objects and asteroids. We will show first results from the daily, short-term processing of Gaia data, all the way from the onboard data acquisition to the ground-based processing. We illustrate the tools developed to compute predictions of asteroid observations, we discuss the procedures implemented by the daily processing, and we illustrate

  5. Threat Mitigation: The Asteroid Tugboat

    CERN Document Server

    Schweickart, R; Durda, D; Hut, P; Chapman, Clark; Durda, Dan; Hut, Piet; Schweickart, Russell

    2006-01-01

    The Asteroid Tugboat (AT) is a fully controlled asteroid deflection concept using a robotic spacecraft powered by a high efficiency, electric propulsion system (ion or plasma) which docks with and attaches to the asteroid, conducts preliminary operations, and then thrusts continuously parallel to the asteroid velocity vector until the desired velocity change is achieved. Based on early warning, provided by ground tracking and orbit prediction, it would be deployed a decade or more prior to a potential impact. On completion of the initial rendezvous with the near-Earth object (NEO) the AT would first reduce the uncertainty in the orbit of the asteroid via Earth tracking of its radio transponder while it is station keeping with the asteroid. If on analysis of tracking data a deflection is required the AT would execute a reconnaissance phase collecting and processing information about the physical characteristics of the asteroid to support subsequent operations. The AT would then dock at the appropriate pole (i....

  6. Asteroids, meteorites, and comets

    CERN Document Server

    Elkins-Tanton, Linda T

    2010-01-01

    Asteroids, Comets, and Meteorites provides students, researchers, and general readers with the most up-to-date information on this fascinating field. From the days of the dinosaurs to our modern environment, this book explores all aspects of these cosmic invaders.

  7. Asteroid Kinetic Impactor Missions

    Science.gov (United States)

    Chesley, Steven

    2015-08-01

    Asteroid impact missions can be carried out as a relatively low-cost add-ons to most asteroid rendezvous missions and such impact experiments have tremendous potential, both scientifically and in the arena of planetary defense.The science returns from an impactor demonstration begin with the documentation of the global effects of the impact, such as changes in orbit and rotation state, the creation and dissipation of an ejecta plume and debris disk, and morphological changes across the body due to the transmission of seismic waves, which might induce landslides and toppling of boulders, etc. At a local level, an inspection of the impact crater and ejecta blanket reveals critical material strength information, as well as spectral differences between the surface and subsurface material.From the planetary defense perspective, an impact demonstration will prove humankind’s capacity to alter the orbit of a potentially threatening asteroid. This technological leap comes in two parts. First, terminal guidance systems that can deliver an impactor with small errors relative to the ~100-200 meter size of a likely impactor have yet to be demonstrated in a deep space environment. Second, the response of an asteroid to such an impact is only understood theoretically due to the potentially significant dependence on the momentum carried by escaping ejecta, which would tend to enhance the deflection by tens of percent and perhaps as much as a factor of a few. A lack of validated understanding of momentum enhancement is a significant obstacle in properly sizing a real-world impactor deflection mission.This presentation will describe the drivers for asteroid impact demonstrations and cover the range of such concepts, starting with ESA’s pioneering Don Quijote mission concept and leading to a brief description of concepts under study at the present time, including the OSIRIS-REx/ISIS, BASiX/KIX and AIM/DART (AIDA) concepts.

  8. Capture of Asteroids and Transport of Asteroid Materials to Earth

    Science.gov (United States)

    Chiu, Hong-Yee; no Team

    2014-01-01

    Recently there has been much discussion on the capture of asteroids or mining the asteroids. While the technology might be years away, in this paper we will discuss an energy efficient method to transport either a small asteroid or materials gathered from asteroids to the Earth. In particular, I will concentrate on a large and nearby asteroid, 8 Flora in the Flora Family. Generally, asteroids are located between 2 to 3 AU (astronomical unit) from the Earth, and in transporting materials from asteroids to the Earth, an energy equivalent of the gravitational potential energy difference between the Earth and the asteroids to the Sun. This amount of potential energy is a sizable fraction of the orbital kinetic energy of the Earth around the Sun. This amount of energy is considerable. In this paper I propose to use the planet Mars as a medium to remove much of the gravitational energy difference. In the case of the asteroid 8 Flora, it is only necessary to decelerate the asteroid mate- rials by a small decrement, of the order of 3 km/sec. This decrement could even be achieved (pending on the availability of technology) by mechanical devices such as catapults on 8 Flora. It is also proposed to separate a pair of contact asteroid binaries by using impulse propulsion, and to propel one component of the separated asteroids to pass by Mars to be decelerated to reach the Earth orbit and captured by the Earth or the Moon. The plausibility of this ambitious project will be discussed. The author is NASA-GSFC Astrophysicist, Retired.

  9. EURONEAR - Data Mining of Asteroids and Near Earth Asteroids

    OpenAIRE

    Vaduvescu, O.; Curelaru, L.; Birlan, M.; Bocsa, G.; Serbanescu, L.; Tudorica, A.; Berthier, J.

    2009-01-01

    Besides new observations, mining old photographic plates and CCD image archives represents an opportunity to recover and secure newly discovered asteroids, also to improve the orbits of Near Earth Asteroids (NEAs), Potentially Hazardous Asteroids (PHAs) and Virtual Impactors (VIs). These are the main research aims of the EURONEAR network. As stated by the IAU, the vast collection of image archives stored worldwide is still insufficiently explored, and could be mined for known NEAs and other a...

  10. Active Asteroids: Main-Belt Comets and Disrupted Asteroids

    CERN Document Server

    Hsieh, Henry H

    2015-01-01

    The study of active asteroids has attracted a great deal of interest in recent years since the recognition of main-belt comets (which orbit in the main asteroid belt, but exhibit comet-like activity due to the sublimation of volatile ices) as a new class of comets in 2006, and the discovery of the first disrupted asteroids (which, unlike MBCs, exhibit comet-like activity due to a physical disruption such as an impact or rotational destabilization, not sublimation) in 2010. In this paper, I will briefly discuss key areas of interest in the study of active asteroids.

  11. Multiple origins of asteroid pairs

    CERN Document Server

    Jacobson, Seth A

    2015-01-01

    Rotationally fissioned asteroids produce unbound daughter asteroids that have very similar heliocentric orbits. Backward integration of their current heliocentric orbits provides an age of closest proximity that can be used to date the rotational fission event. Most asteroid pairs follow a predicted theoretical relationship between the primary spin period and the mass ratio of the two pair members that is a direct consequence of the YORP-induced rotational fission hypothesis. If the progenitor asteroid has strength, asteroid pairs may have high mass ratios with possibly fast rotating primaries. However, secondary fission leaves the originally predicted trend unaltered. We also describe the characteristics of pair members produced by four alternative routes from a rotational fission event to an asteroid pair. Unlike direct formation from the event itself, the age of closest proximity of these pairs cannot generally be used to date the rotational fission event since considerable time may have passed.

  12. Asteroid family ages

    CERN Document Server

    Spoto, Federica; Knezevic, Zoran

    2015-01-01

    A new family classification, based on a catalog of proper elements with $\\sim 384,000$ numbered asteroids and on new methods is available. For the $45$ dynamical families with $>250$ members identified in this classification, we present an attempt to obtain statistically significant ages: we succeeded in computing ages for $37$ collisional families. We used a rigorous method, including a least squares fit of the two sides of a V-shape plot in the proper semimajor axis, inverse diameter plane to determine the corresponding slopes, an advanced error model for the uncertainties of asteroid diameters, an iterative outlier rejection scheme and quality control. The best available Yarkovsky measurement was used to estimate a calibration of the Yarkovsky effect for each family. The results are presented separately for the families originated in fragmentation or cratering events, for the young, compact families and for the truncated, one-sided families. For all the computed ages the corresponding uncertainties are pro...

  13. Asteroid Impact Monitoring

    Science.gov (United States)

    Milani, A.

    2006-06-01

    Some asteroids and comets with Earth-crossing orbit may impact our planet, thus we need to be able to identify the cases which could have a dangerous close approach within a century. This must be done as soon as such an asteroid is discovered, allowing for follow up observations which might contradict the impact possibility, and in the worst case to organize mitigation, possibly including deflection. The mathematical problem of predicting possible impacts, even with very low probabilities, has been solved by our group in the last few years. This paper presents the basic theory of these impact prediction, and discusses how they are practically used in the impact monitoring systems now operational, in particular the CLOMON2 robot of the Universities of Pisa and Valladolid.

  14. Asteroid impact monitoring

    Directory of Open Access Journals (Sweden)

    Milani A.

    2006-01-01

    Full Text Available Some asteroids and comets with Earth-crossing orbit may impact our planet, thus we need to be able to identify the cases which could have a dangerous close approach within a century. This must be done as soon as such an asteroid is discovered, allowing for follow up observations which might contradict the impact possibility, and in the worst case to organize mitigation, possibly including deflection. The mathematical problem of predicting possible impacts, even with very low probabilities, has been solved by our group in the last few years. This paper presents the basic theory of these impact prediction, and discusses how they are practically used in the impact monitoring systems now operational, in particular the CLOMON2 robot of the Universities of Pisa and Valladolid.

  15. Asteroid Surface Geophysics

    CERN Document Server

    Murdoch, Naomi; Schwartz, Stephen R; Miyamoto, Hideaki

    2015-01-01

    The regolith-covered surfaces of asteroids preserve records of geophysical processes that have occurred both at their surfaces and sometimes also in their interiors. As a result of the unique micro-gravity environment that these bodies posses, a complex and varied geophysics has given birth to fascinating features that we are just now beginning to understand. The processes that formed such features were first hypothesised through detailed spacecraft observations and have been further studied using theoretical, numerical and experimental methods that often combine several scientific disciplines. These multiple approaches are now merging towards a further understanding of the geophysical states of the surfaces of asteroids. In this chapter we provide a concise summary of what the scientific community has learned so far about the surfaces of these small planetary bodies and the processes that have shaped them. We also discuss the state of the art in terms of experimental techniques and numerical simulations that...

  16. Silicates in Alien Asteroids

    Science.gov (United States)

    2009-01-01

    This plot of data from NASA's Spitzer Space Telescopes shows that asteroid dust around a dead 'white dwarf' star contains silicates a common mineral on Earth. The data were taken primarily by Spitzer's infrared spectrograph, an instrument that breaks light apart into its basic constituents. The yellow dots show averaged data from the spectrograph, while the orange triangles show older data from Spitzer's infrared array camera. The white dwarf is called GD 40.

  17. The Rafita asteroid family

    Science.gov (United States)

    Aljbaae, S.; Carruba, V.; Masiero, J. R.; Domingos, R. C.; Huaman, M.

    2017-01-01

    The Rafita asteroid family is an S-type group located in the middle main belt, on the right side of the 3J:-1A mean-motion resonance. The proximity of this resonance to the family left side in semi-major axis caused many former family members to be lost. As a consequence, the family shape in the (a, 1/D) domain is quite asymmetrical, with a preponderance of objects on the right side of the distribution. The Rafita family is also characterized by a leptokurtic distribution in inclination, which allows the use of methods of family age estimation recently introduced for other leptokurtic families such as Astrid, Hansa, Gallia, and Barcelona. In this work we propose a new method based on the behavior of an asymmetry coefficient function of the distribution in the (a, 1/D) plane to date incomplete asteroid families such as Rafita. By monitoring the time behavior of this coefficient for asteroids simulating the initial conditions at the time of the family formation, we were able to estimate that the Rafita family should have an age of 490 ± 200 Myr, in good agreement with results from independent methods such as Monte Carlo simulations of Yarkovsky and Yorp dynamical induced evolution and the time behaviour of the kurtosis of the sin (i) distribution. Asteroids from the Rafita family can reach orbits similar to 8% of the currently known near Earth objects. ≃1% of the simulated objects are present in NEO-space during the final 10 Myr of the simulation, and thus would be comparable to objects in the present-day NEO population.

  18. Comet or Asteroid?

    Science.gov (United States)

    1997-11-01

    When is a minor object in the solar system a comet? And when is it an asteroid? Until recently, there was little doubt. Any object that was found to display a tail or appeared diffuse was a comet of ice and dust grains, and any that didn't, was an asteroid of solid rock. Moreover, comets normally move in rather elongated orbits, while most asteroids follow near-circular orbits close to the main plane of the solar system in which the major planets move. However, astronomers have recently discovered some `intermediate' objects which seem to possess properties that are typical for both categories. For instance, a strange object (P/1996 N2 - Elst-Pizarro) was found last year at ESO ( ESO Press Photo 36/96 ) which showed a cometary tail, while moving in a typical asteroidal orbit. At about the same time, American scientists found another (1996 PW) that moved in a very elongated comet-type orbit but was completely devoid of a tail. Now, a group of European scientists, by means of observations carried out at the ESO La Silla observatory, have found yet another object that at first appeared to be one more comet/asteroid example. However, continued and more detailed observations aimed at revealing its true nature have shown that it is most probably a comet . Consequently, it has received the provisional cometary designation P/1997 T3 . The Uppsala-DLR Trojan Survey Some time ago, Claes-Ingvar Lagerkvist (Astronomical Observatory, Uppsala, Sweden), in collaboration with Gerhard Hahn, Stefano Mottola, Magnus Lundström and Uri Carsenty (DLR, Institute of Planetary Exploration, Berlin, Germany), started to study the distribution of asteroids near Jupiter. They were particularly interested in those that move in orbits similar to that of Jupiter and which are located `ahead' of Jupiter in the so-called `Jovian L4 Lagrangian point'. Together with those `behind' Jupiter, these asteroids have been given the names of Greek and Trojan Heroes who participated in the famous Trojan war

  19. AIDA: Asteroid Impact & Deflection Assessment

    Science.gov (United States)

    Cheng, A. F.; Galvez, A.; Carnelli, I.; Michel, P.; Rivkin, A.; Reed, C.

    2012-12-01

    To protect the Earth from a hazardous asteroid impact, various mitigation methods have been proposed, including deflection of the asteroid by a spacecraft impact. AIDA, consisting of two mission elements, the Double Asteroid Redirection Test (DART) and the Asteroid Impact Monitoring (AIM) mission, is a demonstration of asteroid deflection. To date, there has been no such demonstration, and there is major uncertainty in the result of a spacecraft impact onto an asteroid, that is, the amount of deflection produced by a given momentum input from the impact. This uncertainty is in part due to unknown physical properties of the asteroid surface, such as porosity and strength, and in part due to poorly understood impact physics such that the momentum carried off by ejecta is highly uncertain. A first mission to demonstrate asteroid deflection would not only be a major step towards gaining the capability to mitigate an asteroid hazard, but in addition it would return unique information on an asteroid's strength, other surface properties, and internal structure. This information return would be highly relevant to future human exploration of asteroids. We report initial results of the AIDA joint mission concept study undertaken by the Johns Hopkins Applied Physics Laboratory and ESA with support from NASA centers including Goddard, Johnson and Jet Propulsion Laboratory. For AIDA, the DART spacecraft impactor study is coordinated with an ESA study of the AIM mission, which would rendezvous with the same asteroid to measure effects of the impact. Unlike the previous Don Quijote mission study performed by ESA in 2005-2007, DART envisions an impactor spacecraft to intercept the secondary member of a binary near-Earth asteroid. DART includes ground-based observations to measure the deflection independently of the rendezvous spacecraft observations from AIM, which also measures deflection and provides detailed characterization of the target asteroid. The joint mission AIDA

  20. EURONEAR - Data Mining of Asteroids and Near Earth Asteroids

    CERN Document Server

    Vaduvescu, O; Birlan, M; Bocsa, G; Serbanescu, L; Tudorica, A; Berthier, J

    2009-01-01

    Besides new observations, mining old photographic plates and CCD image archives represents an opportunity to recover and secure newly discovered asteroids, also to improve the orbits of Near Earth Asteroids (NEAs), Potentially Hazardous Asteroids (PHAs) and Virtual Impactors (VIs). These are the main research aims of the EURONEAR network. As stated by the IAU, the vast collection of image archives stored worldwide is still insufficiently explored, and could be mined for known NEAs and other asteroids appearing occasionally in their fields. This data mining could be eased using a server to search and classify findings based on the asteroid class and the discovery date as "precoveries" or "recoveries". We built PRECOVERY, a public facility which uses the Virtual Observatory SkyBoT webservice of IMCCE to search for all known Solar System objects in a given observation. To datamine an entire archive, PRECOVERY requires the observing log in a standard format and outputs a database listing the sorted encounters of ...

  1. New Paradigms For Asteroid Formation

    CERN Document Server

    Johansen, Anders; Cuzzi, Jeffrey N; Morbidelli, Alessandro; Gounelle, Matthieu

    2015-01-01

    Asteroids and meteorites provide key evidence on the formation of planetesimals in the Solar System. Asteroids are traditionally thought to form in a bottom-up process by coagulation within a population of initially km-scale planetesimals. However, new models challenge this idea by demonstrating that asteroids of sizes from 100 to 1000 km can form directly from the gravitational collapse of small particles which have organised themselves in dense filaments and clusters in the turbulent gas. Particles concentrate passively between eddies down to the smallest scales of the turbulent gas flow and inside large-scale pressure bumps and vortices. The streaming instability causes particles to take an active role in the concentration, by piling up in dense filaments whose friction on the gas reduces the radial drift compared to that of isolated particles. In this chapter we review new paradigms for asteroid formation and compare critically against the observed properties of asteroids as well as constraints from meteo...

  2. Radar Observations of Asteroids

    Science.gov (United States)

    Ostro, S. J.

    2003-05-01

    During the past 25 years, radar investigations have provided otherwise unavailable information about the physical and dynamical properties of more than 200 asteroids. Measurements of the distribution of echo power in time delay and Doppler frequency provide two-dimensional images with spatial resolution as fine as a decameter. Sequences of delay-Doppler images can be used to produce geologically detailed three-dimensional models, to define the rotation state precisely, to constrain the internal density distribution, and to estimate the trajectory of the object's center of mass. Radar wavelengths (4 to 13 cm) and the observer's control of transmitted and received polarizations make the observations sensitive to near-surface bulk density and macroscopic structure. Since delay-Doppler positional measurements are orthogonal to optical angle measurements and typically have much finer fractional precision, they are powerful for refining orbits and prediction ephemerides. Radar astrometry can add decades or centuries to the interval over which an asteroid's close Earth approaches can accurately be predicted and can significantly refine collision probability estimates based on optical astrometry alone. In the highly unlikely case that a small body is on course for an Earth collision in this century, radar reconnaissance would almost immediately distinguish between an impact trajectory and a near miss and would dramatically reduce the difficulty and cost of any effort to prevent the collision. The sizes and rotation periods of radar-detected asteroids span more than four orders of magnitude. These observations have revealed both stony and metallic objects, elongated and nonconvex shapes as well as nearly featureless spheroids, small-scale morphology ranging from smoother than the lunar regolith to rougher than the rockiest terrain on Mars, craters and diverse linear structures, non-principal-axis spin states, contact binaries, and binary systems.

  3. Radar Investigations of Asteroids

    Science.gov (United States)

    Ostro, S.

    2004-05-01

    Radar investigations have provided otherwise unavailable information about the physical and dynamical properties of about 230 asteroids. Measurements of the distribution of echo power in time delay (range) and Doppler frequency (line-of-sight velocity) provide two-dimensional images with spatial resolution as fine as a decameter. Sequences of delay-Doppler images can be used to produce geologically detailed three-dimensional models, to define the rotation state precisely, to constrain the internal density distribution, and to estimate the trajectory of the object's center of mass. Radar wavelengths (4 to 13 cm) and the observer's control of transmitted and received polarizations make the observations sensitive to near-surface bulk density and macroscopic structure. Since delay-Doppler measurements are orthogonal to optical angle measurements and typically have much finer fractional precision, they are powerful for refining orbits and prediction ephemerides. Such astrometric measurements can add decades or centuries to the interval over which an asteroid's close Earth approaches can accurately be predicted and can significantly refine collision probability estimates based on optical astrometry alone. In the highly unlikely case that a small body is on course for an Earth collision in this century, radar reconnaissance would almost immediately distinguish between an impact trajectory and a near miss and would dramatically reduce the difficulty and cost of any effort to prevent the collision. The sizes and rotation periods of radar-detected asteroids span more than four orders of magnitude. The observations have revealed both stony and metallic objects, elongated and nonconvex shapes as well as nearly featureless spheroids, small-scale morphology ranging from smoother than the lunar regolith to rougher than the rockiest terrain on Mars, craters and diverse linear structures, non-principal-axis spin states, contact binaries, and binary systems.

  4. Asteroids and Comets

    CERN Document Server

    Fernandez, Yanga R; Howell, Ellen S; Woodney, Laura M

    2015-01-01

    Asteroids and comets are remnants from the era of Solar System formation over 4.5 billion years ago, and therefore allow us to address two fundamental questions in astronomy: what was the nature of our protoplanetary disk, and how did the process of planetary accretion occur? The objects we see today have suffered many geophysically-relevant processes in the intervening eons that have altered their surfaces, interiors, and compositions. In this chapter we review our understanding of the origins and evolution of these bodies, discuss the wealth of science returned from spacecraft missions, and motivate important questions to be addressed in the future.

  5. Ion Beam Shepherd for Asteroid Deflection

    CERN Document Server

    Bombardelli, C

    2011-01-01

    We present a novel concept to impart a continuous thrust to an Earth threatening asteroid from a hovering spacecraft without need for physical attachment nor gravitational interaction with the asteroid. The concept involves an ion thruster placed at a distance of a few asteroid diameters directing a stream of quasi-neutral plasma against the asteroid surface resulting into a net transferred momentum. As the transmitted force is independent of the asteroid mass and size the method allows deflecting subkilometer asteroids with a spacecraft much lighter when compared to a gravity tractor spacecraft of equal deflection capability. The finding could make low-cost asteroid deflection missions possible in the coming years.

  6. Asteroids Were Born Big

    CERN Document Server

    Morbidelli, Alessandro; Nesvorny, David; Levison, Harold F

    2009-01-01

    How big were the first planetesimals? We attempt to answer this question by conducting coagulation simulations in which the planetesimals grow by mutual collisions and form larger bodies and planetary embryos. The size frequency distribution (SFD) of the initial planetesimals is considered a free parameter in these simulations, and we search for the one that produces at the end objects with a SFD that is consistent with asteroid belt constraints. We find that, if the initial planetesimals were small (e.g. km-sized), the final SFD fails to fulfill these constraints. In particular, reproducing the bump observed at diameter D~100km in the current SFD of the asteroids requires that the minimal size of the initial planetesimals was also ~100km. This supports the idea that planetesimals formed big, namely that the size of solids in the proto-planetary disk ``jumped'' from sub-meter scale to multi-kilometer scale, without passing through intermediate values. Moreover, we find evidence that the initial planetesimals ...

  7. Design study for asteroidal exploitation

    Science.gov (United States)

    Adams, Carl; Blissit, Jim; Jarrett, Dave; Sanner, Rob; Yanagawa, Koji

    1985-08-01

    A systematic approach to asteroidal exploitation for the 1990 to 2010 time frame is presented as an initial step toward expanding the use of space beyond the space station by providing a source of lower cost materials. With only a limited amount of information known about the asteroids, reconnaissance and exploration phases to determine the exact locations and compositions of several earth-approaching asteroids are required. Earth-based telescopes are used to locate and study the asteroids, while unmanned probes will return samples of asteroidal material to earth for analysis. After these phases are completed, the retrieval of a 35,000 metric ton piece of the asteroid Anteros is undertaken. A cargo transporter uses magnetoplasmadynamic (MPD) arcjets outbound and a mass-driver using asteroidal material inbound. A crew ship uses ion engines. Low thrust trajectories are used for both spacecraft. A materials processing facility will manufacture propellant pellets and retrieve non-propellant materials for spacecraft use. The cost is 1/10th that to transport the same materials from earth to high earth orbit. The project will cost 25 percent less if done in conjunction with a lunar and Martian base.

  8. Images of an Activated Asteroid

    Science.gov (United States)

    Kohler, Susanna

    2016-08-01

    In late April of this year, asteroid P/2016 G1 (PANSTARRS) was discovered streaking through space, a tail of dust extending behind it. What caused this asteroids dust activity?Asteroid or Comet?Images of asteroid P/2016 G1 at three different times: late April, late May, and mid June. The arrow in the center panel points out an asymmetric feature that can be explained if the asteroid initially ejected material in a single direction, perhaps due to an impact. [Moreno et al. 2016]Asteroid P/2016 G1 is an interesting case: though it has the orbital elements of a main-belt asteroid it orbits at just under three times the EarthSun distance, with an eccentricity of e ~ 0.21 its appearance is closer to that of a comet, with a dust tail extending 20 behind it.To better understand the nature and cause of this unusual asteroids activity, a team led by Fernando Moreno (Institute of Astrophysics of Andalusia, in Spain) performed deep observations of P/2016 G1 shortly after its discovery. The team used the 10.4-meter Great Canary Telescope to image the asteroid over the span of roughly a month and a half.A Closer Look at P/2016 G1P/2016 G1 lies in the inner region of the main asteroid belt, so it is unlikely to have any ices that suddenly sublimated, causing the outburst. Instead, Moreno and collaborators suggest that the asteroids tail may have been caused by an impact that disrupted the parent body.To test this idea, the team used computer simulations to model their observations of P/2016 G1s dust tail. Based on their models, they demonstrate that the asteroid was likely activated on February 10 2016 roughly 350 days before it reached perihelion in its orbit and its activity was a short-duration event, lasting only ~24 days. The teams models indicate that over these 24 days, the asteroid lost around 20 million kilograms of dust, and at its maximum activity level, it was ejecting around 8 kg/s!Comparison of the observation from late May (panel a) and two models: one in which

  9. Structural Stability of Asteroids

    Science.gov (United States)

    Hirabayashi, Toshi

    This thesis develops a technique for analyzing the internal structure of an irregularly shaped asteroid. This research focuses on asteroid (216) Kleopatra, a few-hundred-kilometer-sized main belt asteroid spinning about its maximum moment of inertia axis with a rotation period of 5.385 hours, to motivate the techniques. While Ostro et al. [117] reported its dog bone-like shape, estimation of its size has been actively discussed. There are at least three different size estimates: Ostro et al., Descamps et al., and Marchis et al. Descamps et al. reported that (216) Kleopatra has satellites and obtained the mass of this object. This research consists of determination of possible failure modes of (216) Kleopatra and its subsequent detailed stress analysis, with each part including an estimation of the internal structure. The first part of this thesis considers the failure mode of Kleopatra and evaluates the size from it. Possible failure modes are modeled as either material shedding from the surface or plastic failure of the internal structure. The surface shedding condition is met when a zero-velocity curve with the same energy level as one of the dynamical equilibrium points attaches to the surface at the slowest spin period, while the plastic failure condition is characterized by extending the theorem by Holsapple (2008) that the yield condition of the averaged stress over the whole volume is identical to an upper bound for global failure. The prime result shows that while surface shedding does not occur at the current spin period and thus cannot result in the formation of the satellites, the neck may be situated near its plastic deformation state. From the failure condition, we also find that the size estimated by Descamps et al. (2011) is the most structurally stable. The second part of this thesis discusses finite element analyses with an assumption of an elastic-perfectly plastic material and a non-associated flow rule. The yield condition is modeled as the

  10. Solar wind tans young asteroids

    Science.gov (United States)

    2009-04-01

    A new study published in Nature this week reveals that asteroid surfaces age and redden much faster than previously thought -- in less than a million years, the blink of an eye for an asteroid. This study has finally confirmed that the solar wind is the most likely cause of very rapid space weathering in asteroids. This fundamental result will help astronomers relate the appearance of an asteroid to its actual history and identify any after effects of a catastrophic impact with another asteroid. ESO PR Photo 16a/09 Young Asteroids Look Old "Asteroids seem to get a ‘sun tan' very quickly," says lead author Pierre Vernazza. "But not, as for people, from an overdose of the Sun's ultraviolet radiation, but from the effects of its powerful wind." It has long been known that asteroid surfaces alter in appearance with time -- the observed asteroids are much redder than the interior of meteorites found on Earth [1] -- but the actual processes of this "space weathering" and the timescales involved were controversial. Thanks to observations of different families of asteroids [2] using ESO's New Technology Telescope at La Silla and the Very Large Telescope at Paranal, as well as telescopes in Spain and Hawaii, Vernazza's team have now solved the puzzle. When two asteroids collide, they create a family of fragments with "fresh" surfaces. The astronomers found that these newly exposed surfaces are quickly altered and change colour in less than a million years -- a very short time compared to the age of the Solar System. "The charged, fast moving particles in the solar wind damage the asteroid's surface at an amazing rate [3]", says Vernazza. Unlike human skin, which is damaged and aged by repeated overexposure to sunlight, it is, perhaps rather surprisingly, the first moments of exposure (on the timescale considered) -- the first million years -- that causes most of the aging in asteroids. By studying different families of asteroids, the team has also shown that an asteroid

  11. Asteroid named after CAS scientist

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    @@ An asteroid has been named after CAS astronomy historian XI Zezong with the approval of the International Minor Planet Nomenclature Committee (IMPNC), announced China's National Astronomical Observatories at CAS (NAOC) on 17 August.

  12. Near Earth Asteroid Scout Project

    Data.gov (United States)

    National Aeronautics and Space Administration — In considering targets for human asteroid missions, there are several major factors that will make a significant difference in assessment of mission risks that...

  13. Solar Radiation and Asteroidal Motion

    CERN Document Server

    Klacka, J

    2000-01-01

    Effects of solar wind and solar electromagnetic radiation on motion of asteroids are discussed. The results complete the statements presented in Vokrouhlick\\'{y} and Milani (2000). As for the effect of electromagnetic radiation, the complete equation of motion is presented to the first order in $v/c$ -- the shape of asteroid (spherical body is explicitly presented) and surface distribution of albedo should be taken into account. Optical quantities must be calculated in proper frame of reference.

  14. Refining the asteroid taxonomy by polarimetric observations

    Science.gov (United States)

    Belskaya, I. N.; Fornasier, S.; Tozzi, G. P.; Gil-Hutton, R.; Cellino, A.; Antonyuk, K.; Krugly, Yu. N.; Dovgopol, A. N.; Faggi, S.

    2017-03-01

    We present new results of polarimetric observations of 15 main belt asteroids of different composition. By merging new and published data we determined polarimetric parameters characterizing individual asteroids and mean values of the same parameters characterizing different taxonomic classes. The majority of asteroids show polarimetric phase curves close to the average curve of the corresponding class. We show that using polarimetric data it is possible to refine asteroid taxonomy and derive a polarimetric classification for 283 main belt asteroids. Polarimetric observations of asteroid (21) Lutetia are found to exhibit possible variations of the position angle of the polarization plane over the surface.

  15. Asteroid airburst altitude vs. strength

    Science.gov (United States)

    Robertson, Darrel; Wheeler, Lorien; Mathias, Donovan

    2016-10-01

    Small NEO asteroids (<Ø140m) may not be a threat on a national or global level but can still cause a significant amount of local damage as demonstrated by the Chelyabinsk event where there was over $33 million worth of damage (1 billion roubles) and 1500 were injured, mostly due to broken glass. The ground damage from a small asteroid depends strongly on the altitude at which they "burst" where most of the energy is deposited in the atmosphere. The ability to accurately predict ground damage is useful in determining appropriate evacuation or shelter plans and emergency management.Strong asteroids, such as a monolithic boulder, fail and create peak energy deposition close to the altitude at which ram dynamic pressure exceeds the material cohesive strength. Weaker asteroids, such as a rubble pile, structurally fail at higher altitude, but it requires the increased aerodynamic pressure at lower altitude to disrupt and disperse the rubble. Consequently the resulting airbursts have a peak energy deposition at similar altitudes.In this study hydrocode simulations of the entry and break-up of small asteroids were performed to examine the effect of strength, size, composition, entry angle, and speed on the resulting airburst. This presentation will show movies of the simulations, the results of peak burst height, and the comparison to semi-analytical models.

  16. A Gravitational Tractor for Towing Asteroids

    CERN Document Server

    Lu, E T; Lu, Edward T.; Categories, Stanley G. Love

    2005-01-01

    We present a concept for a spacecraft that can controllably alter the trajectory of an Earth threatening asteroid using gravity as a towline. The spacecraft hovers near the asteroid with thrusters angled outward so the exhaust does not impinge on the surface. This deflection method is insensitive to the structure, surface properties, and rotation state of the asteroid.

  17. Benchmarking Asteroid-Deflection Experiment

    Science.gov (United States)

    Remington, Tane; Bruck Syal, Megan; Owen, John Michael; Miller, Paul L.

    2016-10-01

    An asteroid impacting Earth could have devastating consequences. In preparation to deflect or disrupt one before it reaches Earth, it is imperative to have modeling capabilities that adequately simulate the deflection actions. Code validation is key to ensuring full confidence in simulation results used in an asteroid-mitigation plan. We are benchmarking well-known impact experiments using Spheral, an adaptive smoothed-particle hydrodynamics code, to validate our modeling of asteroid deflection. We describe our simulation results, compare them with experimental data, and discuss what we have learned from our work. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. LLNL-ABS-695540

  18. On the Astrid asteroid family

    CERN Document Server

    Carruba, V

    2016-01-01

    Among asteroid families, the Astrid family is peculiar because of its unusual inclination distribution. Objects at $a\\simeq$~2.764 au are quite dispersed in this orbital element, giving the family a "crab-like" appearance. Recent works showed that this feature is caused by the interaction of the family with the $s-s_C$ nodal secular resonance with Ceres, that spreads the inclination of asteroids near its separatrix. As a consequence, the currently observed distribution of the $v_W$ component of terminal ejection velocities obtained from inverting Gauss equation is quite leptokurtic, since this parameter mostly depends on the asteroids inclination. The peculiar orbital configuration of the Astrid family can be used to set constraints on key parameters describing the strength of the Yarkovsky force, such as the bulk and surface density and the thermal conductivity of surface material. By simulating various fictitious families with different values of these parameters, and by demanding that the current value of ...

  19. Spectral Classification of Asteroids by Random Forest

    Science.gov (United States)

    Huang, C.; Ma, Y. H.; Zhao, H. B.; Lu, X. P.

    2016-09-01

    With the increasing asteroid spectral and photometric data, a variety of classification methods for asteroids have been proposed. This paper classifies asteroids based on the observations of Sloan Digital Sky Survey (SDSS) Moving Object Catalogue (MOC) by using the random forest algorithm. With the training data derived from the taxonomies of Tholen, Bus, Lazzaro, DeMeo, and Principal Component Analysis, we classify 48642 asteroids according to g, r, i, and z SDSS magnitudes. In this way, asteroids are divided into 8 spectral classes (C, X, S, B, D, K, L, and V).

  20. Flying Through Dust From Asteroids

    Science.gov (United States)

    Kohler, Susanna

    2016-11-01

    How can we tell what an asteroid is made of? Until now, weve relied on remote spectral observations, though NASAs recently launched OSIRIS-REx mission may soon change this by landing on an asteroid and returning with a sample.But what if we could learn more about the asteroids near Earth without needing to land on each one? It turns out that we can by flying through their dust.The aerogel dust collector of the Stardust mission. [NASA/JPL/Caltech]Ejected CluesWhen an airless body is impacted by the meteoroids prevalent throughout our solar system, ejecta from the body are flung into the space around it. In the case of small objects like asteroids, their gravitational pull is so weak that most of the ejected material escapes, forming a surrounding cloud of dust.By flying a spacecraft through this cloud, we could perform chemical analysis of the dust, thereby determining the asteroids composition. We could even capture some of the dust during a flyby (for example, by using an aerogel collector like in the Stardust mission) and bring it back home to analyze.So whats the best place to fly a dust-analyzing or -collecting spacecraft? To answer this, we need to know what the typical distribution of dust is around a near-Earth asteroid (NEA) a problem that scientists Jamey Szalay (Southwest Research Institute) and Mihly Hornyi (University of Colorado Boulder) address in a recent study.The colors show the density distribution for dust grains larger than 0.3 m around a body with a 10-km radius. The distribution is asymmetric, with higher densities on the apex side, shown here in the +y direction. [Szalay Hornyi 2016]Moon as a LaboratoryTo determine typical dust distributions around NEAs, Szalay and Hornyi first look at the distribution of dust around our own Moon, caused by the same barrage of meteorites wed expect to impact NEAs. The Moons dust cloud was measured in situ in 2013 and 2014 by the Lunar Dust Experiment (LDEX) on board the Lunar Atmosphere and Dust Environment

  1. AsteroidZoo: A New Zooniverse project to detect asteroids and improve asteroid detection algorithms

    Science.gov (United States)

    Beasley, M.; Lewicki, C. A.; Smith, A.; Lintott, C.; Christensen, E.

    2013-12-01

    We present a new citizen science project: AsteroidZoo. A collaboration between Planetary Resources, Inc., the Zooniverse Team, and the Catalina Sky Survey, we will bring the science of asteroid identification to the citizen scientist. Volunteer astronomers have proved to be a critical asset in identification and characterization of asteroids, especially potentially hazardous objects. These contributions, to date, have required that the volunteer possess a moderate telescope and the ability and willingness to be responsive to observing requests. Our new project will use data collected by the Catalina Sky Survey (CSS), currently the most productive asteroid survey, to be used by anyone with sufficient interest and an internet connection. As previous work by the Zooniverse has demonstrated, the capability of the citizen scientist is superb at classification of objects. Even the best automated searches require human intervention to identify new objects. These searches are optimized to reduce false positive rates and to prevent a single operator from being overloaded with requests. With access to the large number of people in Zooniverse, we will be able to avoid that problem and instead work to produce a complete detection list. Each frame from CSS will be searched in detail, generating a large number of new detections. We will be able to evaluate the completeness of the CSS data set and potentially provide improvements to the automated pipeline. The data corpus produced by AsteroidZoo will be used as a training environment for machine learning challenges in the future. Our goals include a more complete asteroid detection algorithm and a minimum computation program that skims the cream of the data suitable for implemention on small spacecraft. Our goal is to have the site become live in the Fall 2013.

  2. Asteroid taxonomic signatures from photometric phase curves

    CERN Document Server

    Oszkiewicz, D A; Wasserman, L H; Muinonen, K; Penttilä, A; Pieniluoma, T; Trilling, D E; Thomas, C A

    2012-01-01

    We explore the correlation between an asteroid's taxonomy and photometric phase curve using the H, G12 photometric phase function, with the shape of the phase function described by the single parameter G12. We explore the usability of G12 in taxonomic classification for individual objects, asteroid families, and dynamical groups. We conclude that the mean values of G12 for the considered taxonomic complexes are statistically different, and also discuss the overall shape of the G12 distribution for each taxonomic complex. Based on the values of G12 for about half a million asteroids, we compute the probabilities of C, S, and X complex membership for each asteroid. For an individual asteroid, these probabilities are rather evenly distributed over all of the complexes, thus preventing meaningful classification. We then present and discuss the G12 distributions for asteroid families, and predict the taxonomic complex preponderance for asteroid families given the distribution of G12 in each family. For certain ast...

  3. Astronomical Observations of Volatiles on Asteroids

    CERN Document Server

    Rivkin, Andrew S; Emery, Joshua P; Howell, Ellen S; Licandro, Javier; Takir, Driss; Vilas, Faith

    2015-01-01

    We have long known that water and hydroxyl are important components in meteorites and asteroids. However, in the time since the publication of Asteroids III, evolution of astronomical instrumentation, laboratory capabilities, and theoretical models have led to great advances in our understanding of H2O/OH on small bodies, and spacecraft observations of the Moon and Vesta have important implications for our interpretations of the asteroidal population. We begin this chapter with the importance of water/OH in asteroids, after which we will discuss their spectral features throughout the visible and near-infrared. We continue with an overview of the findings in meteorites and asteroids, closing with a discussion of future opportunities, the results from which we can anticipate finding in Asteroids V. Because this topic is of broad importance to asteroids, we also point to relevant in-depth discussions elsewhere in this volume.

  4. The Asteroid Redirect Mission (ARM)

    Science.gov (United States)

    Abell, Paul; Gates, Michele; Johnson, Lindley; Chodas, Paul; Mazanek, Dan; Reeves, David; Ticker, Ronald

    2016-07-01

    To achieve its long-term goal of sending humans to Mars, the National Aeronautics and Space Administration (NASA) plans to proceed in a series of incrementally more complex human spaceflight missions. Today, human flight experience extends only to Low-Earth Orbit (LEO), and should problems arise during a mission, the crew can return to Earth in a matter of minutes to hours. The next logical step for human spaceflight is to gain flight experience in the vicinity of the Moon. These cis-lunar missions provide a "proving ground" for the testing of systems and operations while still accommodating an emergency return path to the Earth that would last only several days. Cis-lunar mission experience will be essential for more ambitious human missions beyond the Earth-Moon system, which will require weeks, months, or even years of transit time. In addition, NASA has been given a Grand Challenge to find all asteroid threats to human populations and know what to do about them. Obtaining knowledge of asteroid physical properties combined with performing technology demonstrations for planetary defense provide much needed information to address the issue of future asteroid impacts on Earth. Hence the combined objectives of human exploration and planetary defense give a rationale for the Asteroid Re-direct Mission (ARM). Mission Description: NASA's ARM consists of two mission segments: 1) the Asteroid Redirect Robotic Mission (ARRM), the first robotic mission to visit a large (greater than ~100 m diameter) near-Earth asteroid (NEA), collect a multi-ton boulder from its surface along with regolith samples, demonstrate a planetary defense technique, and return the asteroidal material to a stable orbit around the Moon; and 2) the Asteroid Redirect Crewed Mission (ARCM), in which astronauts will take the Orion capsule to rendezvous and dock with the robotic vehicle, conduct multiple extravehicular activities to explore the boulder, and return to Earth with samples. NASA's proposed

  5. Asteroid magnitudes, UBV colors, and IRAS albedos and diameters

    Science.gov (United States)

    Tedesco, Edward F.

    1989-01-01

    This paper lists absolute magnitudes and slope parameters for known asteroids numbered through 3318. The values presented are those used in reducing asteroid IR flux data obtained with the IRAS. U-B colors are given for 938 asteroids, and B-V colors are given for 945 asteroids. The IRAS albedos and diameters are tabulated for 1790 asteroids.

  6. Asteroid exploration and utilization: The Hawking explorer

    Science.gov (United States)

    Carlson, Alan; Date, Medha; Duarte, Manny; Erian, Neil; Gafka, George; Kappler, Peter; Patano, Scott; Perez, Martin; Ponce, Edgar; Radovich, Brian

    1991-01-01

    The Earth is nearing depletion of its natural resources at a time when human beings are rapidly expanding the frontiers of space. The resources which may exist on asteroids could have enormous potential for aiding and enhancing human space exploration as well as life on Earth. With the possibly limitless opportunities that exist, it is clear that asteroids are the next step for human existence in space. This report comprises the efforts of NEW WORLDS, Inc. to develop a comprehensive design for an asteroid exploration/sample return mission. This mission is a precursor to proof-of-concept missions that will investigate the validity of mining and materials processing on an asteroid. Project STONER (Systematic Transfer of Near Earth Resources) is based on two utilization scenarios: (1) moving an asteroid to an advantageous location for use by Earth; and (2) mining an asteroids and transporting raw materials back to Earth. The asteroid explorer/sample return mission is designed in the context of both scenarios and is the first phase of a long range plane for humans to utilize asteroid resources. The report concentrates specifically on the selection of the most promising asteroids for exploration and the development of an exploration scenario. Future utilization as well as subsystem requirements of an asteroid sample return probe are also addressed.

  7. Asteroids. Prospective energy and material resources

    Energy Technology Data Exchange (ETDEWEB)

    Badescu, Viorel (ed.) [Bucharest Polytechnic Univ. (Romania). Candida Oancea Institute

    2013-11-01

    Recent research on Prospective Energy and Material Resources on Asteroids. Carefully edited book dedicated to Asteroids prospective energy and material resources. Written by leading experts in the field. The Earth has limited material and energy resources while these resources in space are virtually unlimited. Further development of humanity will require going beyond our planet and exploring of extraterrestrial resources and sources of unlimited power. Thus far, all missions to asteroids have been motivated by scientific exploration. However, given recent advancements in various space technologies, mining asteroids for resources is becoming ever more feasible. A significant portion of asteroids value is derived from their location; the required resources do not need to be lifted at a great expense from the surface of the Earth. Resources derived from Asteroid not only can be brought back to Earth but could also be used to sustain human exploration of space and permanent settlements in space. This book investigates asteroids' prospective energy and material resources. It is a collection of topics related to asteroid exploration, and utilization. It presents past and future technologies and solutions to old problems that could become reality in our life time. The book therefore is a great source of condensed information for specialists involved in current and impending asteroid-related activities and a good starting point for space researchers, inventors, technologists and potential investors. Written for researchers, engineers, and businessmen interested in asteroids' exploration and exploitation.

  8. The Asteroid 1998 QE2

    Science.gov (United States)

    Vodniza, Alberto Q.; Pereira, M. R.; Arecibo Observatory Team; JPL Target Asteroids Team

    2013-10-01

    This big asteroid was at 5.8 millions of kilometers from the Earth on May 31 (2013) and it has a diameter of 2.7 km. The radar images obtained by JPL showed that the period of rotation around its axis is close to five hours. Hills. K (2013) reported that the period is of 5.281 +/- 0.002 hours. On June 4 the team of Goldstone-Arecibo found a period of 4.75 +/- 0.01 hours. We also contributed with the light and phase curves to estimate the period by means of the telescope (with red filter). The radar imagery (JPL and Arecibo) revealed that 1998 QE2 has a moon, and we captured a mutual event (eclipse). From our Observatory, located in Pasto-Colombia, we captured several pictures, videos and astrometry data during several days. Our data was published by the Minor Planet Center (MPC) and also appears at the web page of NEODyS. The pictures of the asteroid were captured with the following equipment: CGE PRO 1400 CELESTRON (f/11 Schmidt-Cassegrain Telescope) and STL-1001 SBIG camera. We obtained the light curve of the body. Astrometry was carried out, and we calculated the orbital elements. We obtained the following orbital parameters: eccentricity = 0.5692181, semi-major axis = 2.41104631 A.U, orbital inclination = 12.82771 deg, longitude of the ascending node = 250.16876 deg, argument of perihelion = 345.61328 deg, mean motion = 0.26326658 deg/d, perihelion distance = 1.03863508 A.U, aphelion distance = 3.78345755 A.U. The asteroid has an orbital period of 3.74 years The parameters were calculated based on 191 observations (2013 May: 17-24) with mean residual = 0.162 arcseconds. A video of the asteroid from our Observatory was published on the main page of the “SPACEWEATHER” web: http://www.spaceweather.com/archive.php?view=1&day=21&month=05&year=2013 Note: The autors would like to thank to: Dr. Alessondra Springmann (Arecibo Observatory), Dr. Petr Pravec (Czech Republic), Dr. Lance Benner (JPL), Dr. Carl Hergenrother (Target Asteroids Team), and Dr. Dolores Hill

  9. Asteroids prospective energy and material resources

    CERN Document Server

    2013-01-01

    The Earth has limited material and energy resources while these resources in space are virtually unlimited. Further development of humanity will require going beyond our planet and exploring of extraterrestrial resources and sources of unlimited power.   Thus far, all missions to asteroids have been motivated by scientific exploration. However, given recent advancements in various space technologies, mining asteroids for resources is becoming ever more feasible. A significant portion of asteroids value is derived from their location; the required resources do not need to be lifted at a great expense from the surface of the Earth.   Resources derived from Asteroid not only can be brought back to Earth but could also be used to sustain human exploration of space and permanent settlements in space.   This book investigates asteroids' prospective energy and material resources. It is a collection of topics related to asteroid exploration, and utilization. It presents past and future technologies and solutions t...

  10. Mining the Apollo and Amor asteroids

    Science.gov (United States)

    Oleary, B.

    1977-01-01

    Earth-approaching asteroids could provide raw materials for space manufacturing. For certain asteroids the total energy per unit mass for the transfer of asteroidal resources to a manufacturing site in high earth orbit is comparable to that for lunar materials. For logistical reasons the cost may be many times less. Optical studies suggest that these asteroids have compositions corresponding to those of carbonaceous and ordinary chondrites, with some containing large quantities of iron and nickel; other are thought to contain carbon, nitrogen, and hydrogen, elements that appear to be lacking on the moon. The prospect that several new candidate asteroids will be discovered over the next few years increases the likelihood that a variety of asteroidal resource materials can be retrieved on low-energy missions.

  11. Selecting asteroids for a targeted spectroscopic survey

    CERN Document Server

    Oszkiewicz, D A; Tomov, T; Birlan, M; Geier, S; Penttilä, A; Polińska, M

    2014-01-01

    Asteroid spectroscopy reflects surface mineralogy. There are few thousand asteroids whose surfaces have been observed spectrally. Determining the surface properties of those objects is important for many practical and scientific applications, such as for example developing impact deflection strategies or studying history and evolution of the Solar System and planet formation. The aim of this study is to develop a pre-selection method that can be utilized in searching for asteroids of any taxonomic complex. The method could then be utilized im multiple applications such as searching for the missing V-types or looking for primitive asteroids. We used the Bayes Naive Classifier combined with observations obtained in the course of the Sloan Digital Sky Survey and the Wide-field Infrared Survey Explorer surveys as well as a database of asteroid phase curves for asteroids with known taxonomic type. Using the new classification method we have selected a number of possible V-type candidates. Some of the candidates we...

  12. Eccentricity distribution in the main asteroid belt

    CERN Document Server

    Malhotra, Renu

    2016-01-01

    The observationally complete sample of the main belt asteroids now spans more than two orders of magnitude in size and numbers more than 64,000 (excluding collisional family members). We undertook an analysis of asteroids' eccentricities and their interpretation with simple physical models. We find that Plummer's (1916) conclusion that the asteroids' eccentricities follow a Rayleigh distribution holds for the osculating eccentricities of large asteroids, but the proper eccentricities deviate from a Rayleigh distribution: there is a deficit of eccentricities smaller than $\\sim0.1$ and an excess of larger eccentricities. We further find that the proper eccentricities do not depend significantly on asteroid size but have strong dependence on heliocentric distance: the outer asteroid belt follows a Rayleigh distribution, but the inner belt is strikingly different. Eccentricities in the inner belt can be modeled as a vector sum of a primordial eccentricity vector of random orientation and magnitude drawn from a Ra...

  13. A method to determine asteroid poles

    Science.gov (United States)

    Deangelis, G.

    1993-01-01

    The determination of spin axis and shape is well known to be of fundamental importance for studies about the rotational and physical properties of asteroids. In particular, knowledge that the pole coordinate distribution is random or not could indicate the probable non-Maxwellian distribution of asteroid spin axes, while the distribution in terms of size and shape could place important constraints on the theories about the collisional history of some individual asteroids, of asteroid families, and of the asteroid population as a whole. Many kinds of methods have been developed to determine pole coordinates. An EA method is presented, from which it is possible to obtain the solution with no trial poles, but with a simultaneous least square fit on both the E and A part. Results for rotational and shape parameters were obtained for 18 asteroids: the values of the obtained parameters are generally in close agreement with those of others.

  14. Anchoring a lander on an asteroid using foam stabilization Project

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA has proposed several missions to land a craft on an asteroid and potentially to return samples from it. While large asteroids in the asteroid belt can exhibit a...

  15. 78 FR 51750 - NASA Asteroid Initiative Idea Synthesis Workshop

    Science.gov (United States)

    2013-08-21

    ... SPACE ADMINISTRATION NASA Asteroid Initiative Idea Synthesis Workshop AGENCY: National Aeronautics and... for the agency's Asteroid Initiative. SUMMARY: The National Aeronautics and Space Administration announces a public conference to provide a status on the Agency's Asteroid Initiative planning and to...

  16. 78 FR 64253 - NASA Asteroid Initiative Idea Synthesis Workshop

    Science.gov (United States)

    2013-10-28

    ... SPACE ADMINISTRATION NASA Asteroid Initiative Idea Synthesis Workshop AGENCY: National Aeronautics and... to the recent RFI for the agency's Asteroid Initiative. SUMMARY: The National Aeronautics and Space Administration announces that the agency will resume the NASA Asteroid Initiative Idea Synthesis...

  17. Storyboard GALILEO CRUISE SCIENCE OPPORTUNITIES describes asteroid encounters

    Science.gov (United States)

    1989-01-01

    Storyboard with mosaicked image of an asteroid and entitled GALILEO CRUISE SCIENCE OPPORTUNITIES describes asteroid objectives. These objectives include: first asteroid encounter; surface geology, composition size, shape, mass; and relation of primitive bodies to meteorites.

  18. Recovering and Mining Asteroids with a Gas-Sealed Enclosure

    Science.gov (United States)

    Jenniskens, P.; Damer, B.; Norkus, R.; Pilotz, S.; Grigsby, B.; Adams, C.; Blair, B. R.

    2015-01-01

    The internal structure of weakly consolidated rubble piles and primitive asteroids can be studied closer to home, and such asteroids can be mined, if it is possible to create a gas-sealed enclosure around the asteroid.

  19. Regular Motions of Resonant Asteroids

    Science.gov (United States)

    Ferraz-Mello, S.

    1990-11-01

    RESUMEN. Se revisan resultados analiticos relativos a soluciones regulares del problema asteroidal eliptico promediados en la vecindad de una resonancia con jupiten Mencionamos Ia ley de estructura para libradores de alta excentricidad, la estabilidad de los centros de liberaci6n, las perturbaciones forzadas por la excentricidad de jupiter y las 6rbitas de corotaci6n. ABSTRAC This paper reviews analytical results concerning the regular solutions of the elliptic asteroidal problem averaged in the neighbourhood of a resonance with jupiter. We mention the law of structure for high-eccentricity librators, the stability of the libration centers, the perturbations forced by the eccentricity ofjupiter and the corotation orbits. Key words: ASThROIDS

  20. Colorimetry and magnitudes of asteroids

    Science.gov (United States)

    Bowell, E.; Lumme, K.

    1979-01-01

    In the present paper, 1500 UBV observations are analyzed by a new rather general multiple scattering theory which provided clear insight into previously poorly-recognized optical nature of asteroid surfaces. Thus, phase curves are shown to consist of a surface-texture controlled component, due to singly scattered light, and a component due to multiple scattering. Phase curve shapes can be characterized by a single parameter, the multiple scattering factor, Q. As Q increases, the relative importance of the opposition effect diminishes. Asteroid surfaces are particulate and strikingly similar to texture, being moderately porous and moderately rough on a scale greater than the wavelength of light. In concequence, Q (and also the phase coefficient) correlate well with geometric albedo, and there exists a purely photometric means of determining albedos and diameters.

  1. Comets and Asteroids with FIRST

    Science.gov (United States)

    Bockelée-Morvan, D.; Crovisier, J.

    2001-07-01

    The infrared and microwave domains have proved to be privileged tools to study the physical and chemical properties of small bodies of the Solar System. After a review of the recent results obtained on comets and asteroids in these wavelength ranges, we forecast the major outcomes that can be expected from their observations with the Herschel Space Observatory (hereafter referred as to FIRST, the former denomination). This prospect is focussed on: 1) observations of water rotational lines in comets to measure water outgassing and study water excitation in the coma and its kinematics; 2) observations of HDO in comets to constrain solar nebula models and formation scenarii of comets; 3) the study of surface properties of asteroids.

  2. Stabilities of asteroid orbits in resonances

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A map of the asteroid motion is studied carefully. An exponential diffusion law in the chaotic sea and an algebraic law in the mixed region are observed. The effects of perturbations on diffusion are also discussed. The fixed points, their stabilities and the diffusion properties of the map give qualitative explanations of the distribution of asteroids, i.e. the depletion and accumulation of asteroids in the outer main belt, particularly in the first order mean motion resonances with Jupiter.

  3. Exospheres from Asteroids to Planets

    Science.gov (United States)

    Killen, Rosemary M.; Burger, Matthew H.; Farrell, William M.; DREAM2

    2016-10-01

    The study of exospheres can help us understand the long-term loss of volatiles from planetary bodies due to interactions of planets, satellites, and small bodies with the interplanetary medium (solar wind, meteors, and dust), solar radiation, internal forces including diffusion and outgassing, and surface effects like sticking and chemistry. Recent evidence for water and OH on the moon has spurred interest in processes involving chemistry and sequestration of volatile species at the poles and in voids. In recent years, NASA has sent spacecraft to asteroids including Vesta and Ceres, and ESA sent Rosetta to the asteroids Lutetia and Steins. OSIRIS-REX will return a sample from a primitive asteroid, Bennu, to Earth. It is possible that a Phobos-Deimos flyby will be a precursor to a manned mission to Mars. Exospheric particles are derived from the surface and to some extent from interplanetary dust and meteoroids. By comparing the exospheric compositions before and after major meteor shower events it may be possible to determine the extent to which the exosphere reflects the surface composition. Observation of an escaping exosphere, termed a corona, is challenging. We therefore have embarked on a parametrical study of exospheres as a function of basic controlling parameters such as the mass of the primary object, mass of the exospheric species, heliocentric distance, rotation rate of the primary, composition of the body (asteroid type or icy body). These parameters will be useful for mission planning as well as quick look data to determine the size and location of bodies likely to retain their exospheres and observability of exospheric species. We will also consider the sizes of small clusters that may be gravitationally bound to small bodies such as Phobos. In addition, it is of interest to be able to determine the extent of contamination of the pristine exosphere due to the spacecraft sent to make measurements, and the effect on the measurements of outgassing in the

  4. Near Earth Asteroid (NEA) Scout

    Science.gov (United States)

    Johnson, Les; Castillo-Rogez, Julie; Dervan, Jared; McNutt, Leslie

    2017-01-01

    NASA is developing solar sail propulsion for a near-term Near Earth Asteroid (NEA) reconnaissance mission that will lay the groundwork for the future use of solar sails. The NEA Scout mission will use the sail as primary propulsion allowing it to survey and image one NEA's of interest for future human exploration. NEA Scout will launch on the first mission of the Space Launch System (SLS) in 2018. After its first encounter with the Moon, NEA Scout will enter the sail characterization phase by the 86 square meter sail deployment. A mechanical Active Mass Translation (AMT) system, combined with the remaining ACS propellant, will be used for sail momentum management. The spacecraft will perform a series of lunar flybys to achieve optimum departure trajectory before beginning its two year-long cruise. About one month before the asteroid flyby, NEA Scout will start its approach phase using optical navigation on top of radio tracking. The solar sail will provide NEA Scout continuous low thrust to enable a relatively slow flyby of the target asteroid under lighting conditions favorable to geological imaging. Once complete, NASA will have demonstrated the capability to fly low-cost, high delta V CubeSats to perform interplanetary missions.

  5. Asteroid families, dynamics and astrometry

    Science.gov (United States)

    Williams, J. G.; Gibson, J.

    1987-01-01

    The proper elements and family assignments for the 1227 Palomar-Leiden Survey asteroids of high quality were tabulated. In addition to the large table, there are also auxiliary tables of Mars crossers and commensurate objects, histograms of the proper element distributions, and a discussion. Probably the most important part of the discussion describes the Mars crossing boundary, how the closest distances of approach to Mars and Jupiter are calculated, and why the observed population of Mars crossers should bombard that planet episodically rather than uniformly. Analytical work was done to derive velocity distributions of family forming events from proper element distributions subject to assumptions which may be appropriate for cratering events. Software was developed for a microcomputer to permit plotting of the proper elements. Three orthogonal views are generated and stereo pairs can be printed when desired. This program was created for the study of asteroid families. The astrometry task is directed toward measuring and reducing positions on faint comets and the minor planets with less common orbits. The observational material is CCD frames taken with the Palomar 1.5 m telescope. Positions of 10 comets and 16 different asteroids were published on the Minor Planet Circulars.

  6. Eccentricity distribution in the main asteroid belt

    Science.gov (United States)

    Malhotra, Renu; Wang, Xianyu

    2017-03-01

    The observationally complete sample of the main belt asteroids now spans more than two orders of magnitude in size and numbers more than 64 000 (excluding collisional family members). We undertook an analysis of asteroids' eccentricities and their interpretation with simple physical models. We find that a century old conclusion that the asteroids' eccentricities follow a Rayleigh distribution holds for the osculating eccentricities of large asteroids, but the proper eccentricities deviate from a Rayleigh distribution; there is a deficit of eccentricities smaller than ∼0.1 and an excess of larger eccentricities. We further find that the proper eccentricities do not depend significantly on asteroid size but have strong dependence on heliocentric distance; the outer asteroid belt follows a Rayleigh distribution, but the inner belt is strikingly different. Eccentricities in the inner belt can be modelled as a vector sum of a primordial eccentricity vector of random orientation and magnitude drawn from a Rayleigh distribution of parameter ∼0.06, and an excitation of random phase and magnitude ∼0.13. These results imply that when a late dynamical excitation of the asteroids occurred, it was independent of asteroid size and was stronger in the inner belt than in the outer belt. We discuss implications for the primordial asteroid belt and suggest that the observationally complete sample size of main belt asteroids is large enough that more sophisticated model-fitting of the eccentricities is warranted and could serve to test alternative theoretical models of the dynamical excitation history of asteroids and its links to the migration history of the giant planets.

  7. The Steward Observatory asteroid relational database

    Science.gov (United States)

    Sykes, Mark V.; Alvarezdelcastillo, Elizabeth M.

    1992-01-01

    The Steward Observatory Asteroid Relational Database (SOARD) was created as a flexible tool for undertaking studies of asteroid populations and sub-populations, to probe the biases intrinsic to asteroid databases, to ascertain the completeness of data pertaining to specific problems, to aid in the development of observational programs, and to develop pedagogical materials. To date SOARD has compiled an extensive list of data available on asteroids and made it accessible through a single menu-driven database program. Users may obtain tailored lists of asteroid properties for any subset of asteroids or output files which are suitable for plotting spectral data on individual asteroids. A browse capability allows the user to explore the contents of any data file. SOARD offers, also, an asteroid bibliography containing about 13,000 references. The program has online help as well as user and programmer documentation manuals. SOARD continues to provide data to fulfill requests by members of the astronomical community and will continue to grow as data is added to the database and new features are added to the program.

  8. Periodic Motion near the Surface of Asteroids

    CERN Document Server

    Jiang, Yu; Li, Hengnian

    2015-01-01

    We are interested in the periodic motion and bifurcations near the surface of an asteroid. The gravity field of an irregular asteroid and the equation of motion of a particle near the surface of an asteroid are studied. The periodic motions around the major body of triple asteroid 216 Kleopatra and the OSIRIS REx mission target asteroid 101955 Bennu are discussed. We find that motion near the surface of an irregular asteroid is quite different from the motion near the surface of a homoplastically spheroidal celestial body. The periodic motions around the asteroid 101955 Bennu and 216 Kleopatra indicate that the geometrical shapes of the orbits are probably very sophisticated. There exist both stable periodic motions and unstable periodic motions near the surface of the same irregular asteroid. This periodic motion which is unstable can be resonant or non resonant. The period doubling bifurcation and pseudo period doubling bifurcation of periodic orbits coexist in the same gravity field of the primary of the t...

  9. The Compositional Structure of the Asteroid Belt

    CERN Document Server

    DeMeo, Francesca E; Walsh, Kevin J; Chapman, Clark R; Binzel, Richard P

    2015-01-01

    The past decade has brought major improvements in large-scale asteroid discovery and characterization with over half a million known asteroids and over 100,000 with some measurement of physical characterization. This explosion of data has allowed us to create a new global picture of the Main Asteroid Belt. Put in context with meteorite measurements and dynamical models, a new and more complete picture of Solar System evolution has emerged. The question has changed from "What was the original compositional gradient of the Asteroid Belt?" to "What was the original compositional gradient of small bodies across the entire Solar System?" No longer is the leading theory that two belts of planetesimals are primordial, but instead those belts were formed and sculpted through evolutionary processes after Solar System formation. This article reviews the advancements on the fronts of asteroid compositional characterization, meteorite measurements, and dynamical theories in the context of the heliocentric distribution of...

  10. Origin of igneous meteorites and differentiated asteroids

    Science.gov (United States)

    Scott, E.; Goldstein, J.; Asphaug, E.; Bottke, W.; Moskovitz, N.; Keil, K.

    2014-07-01

    Introduction: Igneously formed meteorites and asteroids provide major challenges to our understanding of the formation and evolution of the asteroid belt. The numbers and types of differentiated meteorites and non-chondritic asteroids appear to be incompatible with an origin by fragmentation of numerous Vesta-like bodies by hypervelocity impacts in the asteroid belt over 4 Gyr. We lack asteroids and achondrites from the olivine-rich mantles of the parent bodies of the 12 groups of iron meteorites and the ˜70 ungrouped irons, the 2 groups of pallasites and the 4--6 ungrouped pallasites. We lack mantle and core samples from the parent asteroids of the basaltic achondrites that do not come from Vesta, viz., angrites and the ungrouped eucrites like NWA 011 and Ibitira. How could core samples have been extracted from numerous differentiated bodies when Vesta's basaltic crust was preserved? Where is the missing Psyche family of differentiated asteroids including the complementary mantle and crustal asteroids [1]? Why are meteorites derived from far more differentiated parent bodies than chondritic parent bodies even though C and S class chondritic asteroids dominate the asteroid belt? New paradigm. Our studies of meteorites, impact modeling, and dynamical studies suggest a new paradigm in which differentiated asteroids accreted at 1--2 au less than 2 Myr after CAI formation [2]. They were rapidly melted by 26Al and disrupted by hit-and-run impacts [3] while still molten or semi-molten when planetary embryos were accreting. Metallic Fe-Ni bodies derived from core material cooled rapidly with little or no silicate insulation less than 4 Myr after CAI formation [4]. Fragments of differentiated planetesimals were subsequently tossed into the asteroid belt. Meteorite evidence for early disruption of differentiated asteroids. If iron meteorites were samples of Fe-Ni cores of bodies that cooled slowly inside silicate mantles over ˜50--100 Myr, irons from each core would have

  11. Reconstructing HST Images of Asteroids

    Science.gov (United States)

    Storrs, A. D.; Bank, S.; Gerhardt, H.; Makhoul, K.

    2003-12-01

    We present reconstructions of images of 22 large main belt asteroids that were observed by Hubble Space Telescope with the Wide-Field/Planetary cameras. All images were restored with the MISTRAL program (Mugnier, Fusco, and Conan 2003) at enhanced spatial resolution. This is possible thanks to the well-studied and stable point spread function (PSF) on HST. We present some modeling of this process and determine that the Strehl ratio for WF/PC (aberrated) images can be improved to 130 ratio of 80 We will report sizes, shapes, and albedos for these objects, as well as any surface features. Images taken with the WFPC-2 instrument were made in a variety of filters so that it should be possible to investigate changes in mineralogy across the surface of the larger asteroids in a manner similar to that done on 4 Vesta by Binzel et al. (1997). Of particular interest are a possible water of hydration feature on 1 Ceres, and the non-observation of a constriction or gap between the components of 216 Kleopatra. Reduction of this data was aided by grant HST-GO-08583.08A from the Space Telescope Science Institute. References: Mugnier, L.M., T. Fusco, and J.-M. Conan, 2003. JOSA A (submitted) Binzel, R.P., Gaffey, M.J., Thomas, P.C., Zellner, B.H., Storrs, A.D., and Wells, E.N. 1997. Icarus 128 pp. 95-103

  12. Olivine-dominated Asteroids: Mineralogy and Origin

    CERN Document Server

    Sanchez, Juan A; Kelley, Michael S; Cloutis, Edward A; Bottke, William F; Nesvorný, David; Lucas, Michael P; Hardersen, Paul S; Gaffey, Michael J; Abell, Paul A; Corre, Lucille Le

    2013-01-01

    Olivine-dominated asteroids are a rare type of objects formed either in nebular processes or through magmatic differentiation. The analysis of meteorite samples suggest that at least 100 parent bodies in the main belt experienced partial or complete melting and differentiation before being disrupted. However, only a few olivine-dominated asteroids, representative of the mantle of disrupted differentiated bodies, are known to exist. Due to the paucity of these objects in the main belt their origin and evolution have been a matter of great debate over the years. In this work we present a detailed mineralogical analysis of twelve olivine-dominated asteroids. Within our sample we distinguish two classes, one that we call pure-olivine asteroids and another referred to as olivine-rich asteroids. For the pure-olivine asteroids the olivine chemistry was found to range from ~ Fo49 to Fo70, consistent with the values measured for brachinites and R chondrites. In the case of the olivine-rich asteroids we determined thei...

  13. Rotational Study of Ambiguous Taxonomic Classified Asteroids

    Science.gov (United States)

    Linder, Tyler R.; Sanchez, Rick; Wuerker, Wolfgang; Clayson, Timothy; Giles, Tucker

    2017-01-01

    The Sloan Digital Sky Survey (SDSS) moving object catalog (MOC4) provided the largest ever catalog of asteroid spectrophotometry observations. Carvano et al. (2010), while analyzing MOC4, discovered that individual observations of asteroids which were observed multiple times did not classify into the same photometric-based taxonomic class. A small subset of those asteroids were classified as having both the presence and absence of a 1um silicate absorption feature. If these variations are linked to differences in surface mineralogy, the prevailing assumption that an asteroid’s surface composition is predominantly homogenous would need to be reexamined. Furthermore, our understanding of the evolution of the asteroid belt, as well as the linkage between certain asteroids and meteorite types may need to be modified.This research is an investigation to determine the rotational rates of these taxonomically ambiguous asteroids. Initial questions to be answered:Do these asteroids have unique or nonstandard rotational rates?Is there any evidence in their light curve to suggest an abnormality?Observations were taken using PROMPT6 a 0.41-m telescope apart of the SKYNET network at Cerro Tololo Inter-American Observatory (CTIO). Observations were calibrated and analyzed using Canopus software. Initial results will be presented at AAS.

  14. Target Asteroids! Observing Campaigns for April through June 2017

    Science.gov (United States)

    Hergenrother, Carl; Hill, Dolores

    2017-04-01

    Asteroid campaigns to be conducted by the Target Asteroids! program during the April-June 2017 quarter are described. In addition to asteroids on the original Target Asteroids! list of easily accessible spacecraft targets, an effort has been made to identify other asteroids that are 1) brighter and easier to observe for small telescope users and 2) analogous to (101955) Bennu and (162173) Ryugu, targets of the OSIRIS-REx and Hayabusa-2 sample return missions.

  15. Dynamics of rotationally fissioned asteroids: Source of observed small asteroid systems

    CERN Document Server

    Jacobson, Seth A

    2014-01-01

    We present a model of near-Earth asteroid (NEA) rotational fission and ensuing dynamics that describes the creation of synchronous binaries and all other observed NEA systems including: doubly synchronous binaries, high- e binaries, ternary systems, and contact binaries. Our model only presupposes the Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) effect, "rubble pile" asteroid geophysics, and gravitational interactions. The YORP effect torques a "rubble pile" asteroid until the asteroid reaches its fission spin limit and the components enter orbit about each other (Scheeres, D.J. [2007]. Icarus 189, 370-385). Non-spherical gravitational potentials couple the spin states to the orbit state and chaotically drive the system towards the observed asteroid classes along two evolutionary tracks primarily distinguished by mass ratio. Related to this is a new binary process termed secondary fission - the secondary asteroid of the binary system is rotationally accelerated via gravitational torques until it fissions, thu...

  16. Difficult cases in photometric studies of asteroids

    Science.gov (United States)

    Marciniak, Anna; Pilcher, Frederick; Oszkiewicz, Dagmara; Bartczak, Przemysław; Santana-Ros, Toni; Kamiński, Krzysztof; Urakawa, Seitaro; Ogłoza, Waldemar; Fauvaud, Stéphane; Kankiewicz, Paweł; Kudak, Viktor; Żejmo, Michał; Nishiyama, Kota; Okumura, Shin-ichiro; Nimura, Tokuhiro; Hirsch, Roman; Konstanciak, Izabella; Tychoniec, Łukasz; Figas, Michał

    2016-06-01

    We present a photometric campaign targeted at asteroids that display both long periods of rotation and small amplitudes of brightness variations. Our aim is to debias available sample of spin and shape modelled asteroids and to correct previous wrong period determinations. Our newest findings are corrected period determinations for asteroids (279) Thule (P=23.896h ± 0.005 h), (673) Edda (P=22.340h ± 0.004 h), and (737) Arequipa (P=7.0259h ± 0.0003 h). Supporting lightcurves are presented in this paper.

  17. Spectroscopy of near-Earth asteroids

    DEFF Research Database (Denmark)

    Michelsen, René; Nathues, Andreas; Lagerkvist, Claes-Ingvar

    2006-01-01

    We present spectra and taxonomic classifications of 12 Near-Earth Asteroids (NEAs) and 2 inner Main Belt asteroids. The observations were carried out with the ESO 3.5 m NTT and the Danish 1.54 m telescope at La Silla, Chile. Eleven of the investigated NEAs belong to the S class while only one C......-type has been identified. Two NEAs were observed at phase angles larger than 60 degrees introducing significant phase reddening. In order to allow for comparisons between spectra of asteroids observed at different phase angles we make attempts to correct for this effect. However, it turned out...

  18. Asteroids@home - A BOINC distributed computing project for asteroid shape reconstruction

    CERN Document Server

    Durech, Josef; Vanco, Radim

    2015-01-01

    We present the project Asteroids@home that uses distributed computing to solve the time-consuming inverse problem of shape reconstruction of asteroids. The project uses the Berkeley Open Infrastructure for Network Computing (BOINC) framework to distribute, collect, and validate small computational units that are solved independently at individual computers of volunteers connected to the project. Shapes, rotational periods, and orientations of the spin axes of asteroids are reconstructed from their disk-integrated photometry by the lightcurve inversion method.

  19. ASIME 2016 White Paper: In-Space Utilisation of Asteroids: "Answers to Questions from the Asteroid Miners"

    OpenAIRE

    Graps, Amara L.; Blondel, Philippe; Bonin, Grant; Britt, Daniel; Centuori, Simone; Delbo, Marco; Drube, Line; Duffard, Rene; Elvis, Martin; Faber, Daniel; Frank, Elizabeth; Galache, JL; Green, Simon F.; Grundmann, Jan Thimo; Hsieh, Henry

    2016-01-01

    The aim of the Asteroid Science Intersections with In-Space Mine Engineering (ASIME) 2016 conference on September 21-22, 2016 in Luxembourg City was to provide an environment for the detailed discussion of the specific properties of asteroids, with the engineering needs of space missions that utilize asteroids. The ASIME 2016 Conference produced a layered record of discussions from the asteroid scientists and the asteroid miners to understand each other's key concerns and to address key scien...

  20. Water in Asteroid 4 Vesta

    Science.gov (United States)

    Taylor, G. J.

    2015-01-01

    Eucrite meteorites come from asteroid 4 Vesta, which was recently studied from orbit by NASA's Dawn mission. Adam Sarafian (Woods Hole Oceanographic Institute) and colleagues at Woods Hole, the University of Bristol, England, and the University of New Mexico measured the hydrogen concentration and deuterium/hydrogen (D/H) ratio in crystals of the mineral apatite (calcium phosphate) in eucrites. They found that the D/H ratio is in the same range as in carbonaceous chondrites, most samples of the Earth's mantle, and in samples of basaltic meteorites from Mars. Combined with measurements of the isotopic compositions of nitrogen and carbon, the data suggest that these volatile elements were added to Earth early in its history, probably during its formation. Other studies conclude that water with D/H like that in carbonaceous chondrites, Earth, Mars, and Vesta were likely inherited from interstellar ice that predates formation of the solar system.

  1. Chelyabinsk: Portrait of an asteroid airburst

    Energy Technology Data Exchange (ETDEWEB)

    Kring, David A.; Boslough, Mark

    2014-09-01

    Video and audio from hundreds of smartphones and dashboard cameras combined with seismic, acoustic, and satellite measurements provide the first precise documentation of a 10 000-ton asteroid explosion.

  2. Origins for the near-earth asteroids

    Science.gov (United States)

    Binzel, Richard P.; Xu, Shui; Bus, Schelte J.; Bowell, Edward

    1992-01-01

    Because of their short dynamical lifetimes, the population of near-earth asteroids (NEAs) must be resupplied. Two sources have been hypothesized: main-belt asteroids and extinct comet nuclei. A new survey of physical properties for less than 5 kilometers diameter main-belt asteroids reveals that their spin rate and shape distributions are similar to those of NEAs, as is fully consistent with a main-belt origin for most NEAs. Physical data on comet nuclei are limited. If the existing sample is representative of the comet population, analysis of the asteroid and comet samples constrains the fraction of comet nuclei to between 0 and 40 percent of the total NEA population.

  3. Mineralogy and Surface Composition of Asteroids

    CERN Document Server

    Reddy, Vishnu; Thomas, Cristina A; Moskovitz, Nicholas A; Burbine, Thomas H

    2015-01-01

    Methods to constrain the surface mineralogy of asteroids have seen considerable development during the last decade with advancement in laboratory spectral calibrations and validation of our interpretive methodologies by spacecraft rendezvous missions. This has enabled the accurate identification of several meteorite parent bodies in the main asteroid belt and helped constrain the mineral chemistries and abundances in ordinary chondrites and basaltic achondrites. With better quantification of spectral effects due to temperature, phase angle, and grain size, systematic discrepancies due to non-compositional factors can now be virtually eliminated for mafic silicate-bearing asteroids. Interpretation of spectrally featureless asteroids remains a challenge. This paper presents a review of all mineralogical interpretive tools currently in use and outlines procedures for their application.

  4. The Cratering History of Asteroid (21) Lutetia

    CERN Document Server

    Marchi, S; Vincent, J -B; Morbidelli, A; Mottola, S; Marzari, F; Kueppers, M; Besse, S; Thomas, N; Barbieri, C; Naletto, G; Sierks, H

    2011-01-01

    The European Space Agency's Rosetta spacecraft passed by the main belt asteroid (21) Lutetia the 10th July 2010. With its ~100km size, Lutetia is one of the largest asteroids ever imaged by a spacecraft. During the flyby, the on-board OSIRIS imaging system acquired spectacular images of Lutetia's northern hemisphere revealing a complex surface scarred by numerous impact craters, reaching the maximum dimension of about 55km. In this paper, we assess the cratering history of the asteroid. For this purpose, we apply current models describing the formation and evolution of main belt asteroids, that provide the rate and velocity distributions of impactors. These models, coupled with appropriate crater scaling laws, allow us to interpret the observed crater size-frequency distribution (SFD) and constrain the cratering history. Thanks to this approach, we derive the crater retention age of several regions on Lutetia, namely the time lapsed since their formation or global surface reset. We also investigate the influe...

  5. Colors of Dynamically Associated Asteroid Pairs

    CERN Document Server

    Moskovitz, Nicholas

    2012-01-01

    Recent dynamical studies have identified pairs of asteroids that reside in nearly identical heliocentric orbits. Possible formation scenarios for these systems include dissociation of binary asteroids, collisional disruption of a single parent body, or spin-up and rotational fission of a rubble-pile. Aside from detailed dynamical analyses and measurement of rotational light curves, little work has been done to investigate the colors or spectra of these unusual objects. A photometric and spectroscopic survey was conducted to determine the reflectance properties of asteroid pairs. New observations were obtained for a total of 34 individual asteroids. Additional photometric measurements were retrieved from the Sloan Digital Sky Survey Moving Object Catalog. Colors or spectra for a total of 42 pair components are presented here. The main findings of this work are: (1) the components in the observed pair systems have the same colors within the uncertainties of this survey, and (2) the color distribution of asteroi...

  6. An Early Warning System for Asteroid Impact

    Science.gov (United States)

    Tonry, John L.

    2011-01-01

    Earth is bombarded by meteors, occasionally by one large enough to cause a significant explosion and possible loss of life. It is not possible to detect all hazardous asteroids, and the efforts to detect them years before they strike are only advancing slowly. Similarly, ideas for mitigation of the danger from an impact by moving the asteroid are in their infancy. Although the odds of a deadly asteroid strike in the next century are low, the most likely impact is by a relatively small asteroid, and we suggest that the best mitigation strategy in the near term is simply to move people out of the way. With enough warning, a small asteroid impact should not cause loss of life, and even portable property might be preserved. We describe an early warning system that could provide a week’s notice of most sizeable asteroids or comets on track to hit the Earth. This may be all the mitigation needed or desired for small asteroids, and it can be implemented immediately for relatively low cost. This system, dubbed Asteroid Terrestrial-Impact Last Alert System (ATLAS), comprises two observatories separated by about 100 km that simultaneously scan the visible sky twice a night. Software automatically registers a comparison with the unchanging sky and identifies everything that has moved or changed. Communications between the observatories lock down the orbits of anything approaching the Earth, within one night if its arrival is less than a week. The sensitivity of the system permits detection of 140 m asteroids (100 Mton impact energy) three weeks before impact and 50 m asteroids a week before arrival. An ATLAS alarm, augmented by other observations, should result in a determination of impact location and time that is accurate to a few kilometers and a few seconds. In addition to detecting and warning of approaching asteroids, ATLAS will continuously monitor the changing universe around us: most of the variable stars in our Galaxy, many microlensing events from stellar

  7. Asteroid models from the Lowell photometric database

    Science.gov (United States)

    Ďurech, J.; Hanuš, J.; Oszkiewicz, D.; Vančo, R.

    2016-03-01

    Context. Information about shapes and spin states of individual asteroids is important for the study of the whole asteroid population. For asteroids from the main belt, most of the shape models available now have been reconstructed from disk-integrated photometry by the lightcurve inversion method. Aims: We want to significantly enlarge the current sample (~350) of available asteroid models. Methods: We use the lightcurve inversion method to derive new shape models and spin states of asteroids from the sparse-in-time photometry compiled in the Lowell Photometric Database. To speed up the time-consuming process of scanning the period parameter space through the use of convex shape models, we use the distributed computing project Asteroids@home, running on the Berkeley Open Infrastructure for Network Computing (BOINC) platform. This way, the period-search interval is divided into hundreds of smaller intervals. These intervals are scanned separately by different volunteers and then joined together. We also use an alternative, faster, approach when searching the best-fit period by using a model of triaxial ellipsoid. By this, we can independently confirm periods found with convex models and also find rotation periods for some of those asteroids for which the convex-model approach gives too many solutions. Results: From the analysis of Lowell photometric data of the first 100 000 numbered asteroids, we derived 328 new models. This almost doubles the number of available models. We tested the reliability of our results by comparing models that were derived from purely Lowell data with those based on dense lightcurves, and we found that the rate of false-positive solutions is very low. We also present updated plots of the distribution of spin obliquities and pole ecliptic longitudes that confirm previous findings about a non-uniform distribution of spin axes. However, the models reconstructed from noisy sparse data are heavily biased towards more elongated bodies with high

  8. Olivine-dominated asteroids: Mineralogy and origin

    OpenAIRE

    Sanchez, Juan A.; Reddy, Vishnu; Kelley, Michael S.; Cloutis, Edward A.; Bottke, William F.; Nesvorný, David; Lucas, Michael P.; Hardersen, Paul S.; Gaffey, Michael J.; Abell, Paul A.; Corre, Lucille Le

    2013-01-01

    Olivine-dominated asteroids are a rare type of objects formed either in nebular processes or through magmatic differentiation. The analysis of meteorite samples suggest that at least 100 parent bodies in the main belt experienced partial or complete melting and differentiation before being disrupted. However, only a few olivine-dominated asteroids, representative of the mantle of disrupted differentiated bodies, are known to exist. Due to the paucity of these objects in the main belt their or...

  9. Modelling asteroid brightness variations. I - Numerical methods

    Science.gov (United States)

    Karttunen, H.

    1989-01-01

    A method for generating lightcurves of asteroid models is presented. The effects of the shape of the asteroid and the scattering law of a surface element are distinctly separable, being described by chosen functions that can easily be changed. The shape is specified by means of two functions that yield the length of the radius vector and the normal vector of the surface at a given point. The general shape must be convex, but spherical concavities producing macroscopic shadowing can also be modeled.

  10. Asteroid secular dynamics: Ceres' fingerprint identified

    CERN Document Server

    Novaković, Bojan; Tsirvoulis, Georgios; Knezević, Zoran

    2015-01-01

    Here we report on the significant role of a so far overlooked dynamical aspect, namely a secular resonance between the dwarf planet Ceres and other asteroids. We demonstrate that this type of secular resonance can be the dominant dynamical factor in certain regions of the main asteroid belt. Specifically, we performed a dynamical analysis of the asteroids belonging to the (1726) Hoffmeister family. To identify which dynamical mechanisms are actually at work in this part of the main asteroid belt, i.e. to isolate the main perturber(s), we study the evolution of this family in time. The study is accomplished using numerical integrations of test particles performed within different dynamical models. The obtained results reveal that the post-impact evolution of the Hoffmeister asteroid family is a direct consequence of the nodal secular resonance with Ceres. This leads us to the conclusion that similar effects must exist in other parts of the asteroid belt. In this respect, the obtained results shed light on an i...

  11. An Early Warning System for Asteroid Impact

    CERN Document Server

    Tonry, John L

    2010-01-01

    Earth is bombarded by meteors, occasionally by one large enough to cause a significant explosion and possible loss of life. Although the odds of a deadly asteroid strike in the next century are low, the most likely impact is by a relatively small asteroid, and we suggest that the best mitigation strategy in the near term is simply to move people out of the way. We describe an "early warning" system that could provide a week's notice of most sizable asteroids or comets on track to hit the Earth. This system, dubbed "Asteroid Terrestrial-impact Last Alert System" (ATLAS), comprises two observatories separated by about 100km that simultaneously scan the visible sky twice a night, and can be implemented immediately for relatively low cost. The sensitivity of ATLAS permits detection of 140m asteroids (100 Mton impact energy) three weeks before impact, and 50m asteroids a week before arrival. An ATLAS alarm, augmented by other observations, should result in a determination of impact location and time that is accura...

  12. Asteroid hyalosis--current state of knowledge.

    Science.gov (United States)

    Jabłońska, Anna; Ciszewska, Joanna; Kęcik, Dariusz

    2014-01-01

    The search query into the Cochrane Library, Medline, Web of Science, Embase, Scopus and ScienceDirect enabled selection of research papers addressing the issue of asteroid hyalosis published in English between 1963 and January 2014. Asteroid hyalosis is a degenerative condition of the vitreous in which small, creamy or white, spherical particles (asteroid bodies) are randomly diffused within the vitreous. They consist mainly of calcium and phosphorus and have a structure of hydroxy lapatite. In 80.2-92.0% of cases the condition affects one eye only and it occurs in 0.36-1.96% of population, mostly in patients over 50 years of age and in males. Hypercholesterolemia and hypertension are systemic risk factors, but asteroid hyalosis is postulated to occur more often in retinitis pigmentosa and Leber amaurosis caused by mutations in lecithin retinol acyltransferase gene. Asteroid hyalosis also causes calcification of some intraocular lenses--mostly silicone ones. Vitreous of patients with asteroid hyalosis shows reduced gel liquefaction and anomalous vitreoretinal adhesion.

  13. Formation of asteroid pairs by rotational fission.

    Science.gov (United States)

    Pravec, P; Vokrouhlický, D; Polishook, D; Scheeres, D J; Harris, A W; Galád, A; Vaduvescu, O; Pozo, F; Barr, A; Longa, P; Vachier, F; Colas, F; Pray, D P; Pollock, J; Reichart, D; Ivarsen, K; Haislip, J; Lacluyze, A; Kusnirák, P; Henych, T; Marchis, F; Macomber, B; Jacobson, S A; Krugly, Yu N; Sergeev, A V; Leroy, A

    2010-08-26

    Pairs of asteroids sharing similar heliocentric orbits, but not bound together, were found recently. Backward integrations of their orbits indicated that they separated gently with low relative velocities, but did not provide additional insight into their formation mechanism. A previously hypothesized rotational fission process may explain their formation-critical predictions are that the mass ratios are less than about 0.2 and, as the mass ratio approaches this upper limit, the spin period of the larger body becomes long. Here we report photometric observations of a sample of asteroid pairs, revealing that the primaries of pairs with mass ratios much less than 0.2 rotate rapidly, near their critical fission frequency. As the mass ratio approaches 0.2, the primary period grows long. This occurs as the total energy of the system approaches zero, requiring the asteroid pair to extract an increasing fraction of energy from the primary's spin in order to escape. We do not find asteroid pairs with mass ratios larger than 0.2. Rotationally fissioned systems beyond this limit have insufficient energy to disrupt. We conclude that asteroid pairs are formed by the rotational fission of a parent asteroid into a proto-binary system, which subsequently disrupts under its own internal system dynamics soon after formation.

  14. An ISU study of asteroid mining

    Science.gov (United States)

    Burke, J. D.

    1991-01-01

    During the 1990 summer session of the International Space University, 59 graduate students from 16 countries carried out a design project on using the resources of near-earth asteroids. The results of the project, whose full report is now available from ISU, are summarized. The student team included people in these fields: architecture, business and management, engineering, life sciences, physical sciences, policy and law, resources and manufacturing, and satellite applications. They designed a project for transporting equipment and personnel to a near-earth asteroid, setting up a mining base there, and hauling products back for use in cislunar space. In addition, they outlined the needed precursor steps, beginning with expansion of present ground-based programs for finding and characterizing near-earth asteroids and continuing with automated flight missions to candidate bodies. (To limit the summer project's scope the actual design of these flight-mission precursors was excluded.) The main conclusions were that asteroid mining may provide an important complement to the future use of lunar resources, with the potential to provide large amounts of water and carbonaceous materials for use off earth. However, the recovery of such materials from presently known asteroids did not show an economic gain under the study assumptions; therefore, asteroid mining cannot yet be considered a prospective business.

  15. Asteroid Models from Multiple Data Sources

    CERN Document Server

    Durech, J; Delbo, M; Kaasalainen, M; Viikinkoski, M

    2015-01-01

    In the past decade, hundreds of asteroid shape models have been derived using the lightcurve inversion method. At the same time, a new framework of 3-D shape modeling based on the combined analysis of widely different data sources such as optical lightcurves, disk-resolved images, stellar occultation timings, mid-infrared thermal radiometry, optical interferometry, and radar delay-Doppler data, has been developed. This multi-data approach allows the determination of most of the physical and surface properties of asteroids in a single, coherent inversion, with spectacular results. We review the main results of asteroid lightcurve inversion and also recent advances in multi-data modeling. We show that models based on remote sensing data were confirmed by spacecraft encounters with asteroids, and we discuss how the multiplication of highly detailed 3-D models will help to refine our general knowledge of the asteroid population. The physical and surface properties of asteroids, i.e., their spin, 3-D shape, densit...

  16. Lightcurves for Two Near-Earth Asteroids by Asteroids Observers (OBAS) - MPPD: 2016 April-May

    Science.gov (United States)

    Martinez, Vicente Mas; Silva, Gonzalo Fornas; Martinez, Angel Flores; Garceran, Alfonso Carreno; Mansego, Enrique Arce; Rodriguez, Pedro Brines; de Haro, Juan Lozano; Silva, Alvaro Fornas; Chiner, Onofre Rodrigo; Porta, David Herrero

    2016-10-01

    We report on the results of photometric analysis of two near-Earth asteroids (NEA) by Asteroids Observers (OBAS). This work is part of the Minor Planet Photometric Database (MPPD) project initiated by a group of Spanish amateur astronomers. We have managed to obtain a number of accurate and complete lightcurves as well as some additional incomplete lightcurves to help analysis at future oppositions.

  17. Eighteen Asteroids Lightcurves at Asteroides Observers (OBAS) - MPPD: 2016 March-May

    Science.gov (United States)

    Mansego, Enrique Arce; Rodriguez, Pedro Brines; de Haro, Juan Lozano; Chiner, Onofre Rodrigo; Silva, Alvaro Fornas; Porta, David Herrero; Martinez, Vicente Mas; Silva, Gonzalo Fornas; Garceran, Alfonso Carreno

    2016-10-01

    We report on the analysis of photometric observations of 18 main-belt asteroids (MBA) done by Asteroides Observers (OBAS). This work is part of the Minor Planet Photometric Database program initiated by a group of Spanish amateur astronomers. We have managed to obtain a number of accurate and complete lightcurves as well as some additional incomplete lightcurves to help analysis at future oppositions.

  18. Sixteen Asteroids Lightcurves at Asteroids Observers (OBAS) - MPPD: 2016 June-November

    Science.gov (United States)

    Brines, Pedro; Lozano, Juan; Rodrigo, Onofre; Fornas, A.; Herrero, David; Mas, Vicente; Fornas, G.; Carreño, A.; Arce, Enrique

    2017-04-01

    We report on the photometric analysis result of sixteen main-belt asteroids (MBA) done by Asteroids Observers (OBAS). This work is part of the Minor Planet Photometric Database tasks, initiated by a group of Spanish amateur astronomers. We have managed to obtain a number of accurate and complete lightcurves as well as some additional incomplete lightcurves to help analysis at future oppositions.

  19. Twenty-three Asteroids Lightcurves at Observadores de Asteroides (OBAS): 2015 October - December

    Science.gov (United States)

    Aznar Macias, Amadeo; Carreno Garcerain, Alfonso; Arce Mansego, Enrique; Brines Rodriguez, Pedro; Lozano de Haro, Juan; Fornas Silva, Alvaro; Fornas Silva, Gonzalo; Mas Martinez, Vicente; Rodrigo Chiner, Onofre

    2016-04-01

    We report on the photometric analysis results for 23 main-belt asteroids (MBA) done by Observadores de Asteroides (OBAS). This work is part of the Minor Planet Photometric Database that was initiated by a group of Spanish amateur astronomers. We have managed to obtain a number of accurate, complete lightcurves as well as some additional incomplete lightcurves to help analysis at future oppositions.

  20. Lightcurve Survey of V-type Asteroids in the Inner Asteroid Belt

    CERN Document Server

    Hasegawa, Sunao; Mito, Hiroyuki; Sarugaku, Yuki; Ozawa, Tomohiko; Kuroda, Daisuke; Nishihara, Setsuko; Harada, Akari; Yoshida, Michitoshi; Yanagisawa, Kenshi; Shimizu, Yasuhiro; Nagayama, Shogo; Toda, Hiroyuki; Okita, Kouji; Kawai, Nobuyuki; Mori, Machiko; Sekiguchi, Tomohiko; Ishiguro, Masateru; Abe, Takumi; Abe, Masanao

    2013-01-01

    We have observed the lightcurves of 13 V-type asteroids ((1933) Tinchen, (2011) Veteraniya, (2508) Alupka, (3657) Ermolova, (3900) Knezevic, (4005) Dyagilev, (4383) Suruga, (4434) Nikulin, (4796) Lewis, (6331) 1992 $\\mathrm{FZ_{1}}$, (8645) 1998 TN, (10285) Renemichelsen, and (10320) Reiland). Using these observations we determined the rotational rates of the asteroids, with the exception of Nikulin and Renemichelsen. The distribution of rotational rates of 59 V-type asteroids in the inner main belt, including 29 members of the Vesta family that are regarded as ejecta from the asteroid (4) Vesta, is inconsistent with the best-fit Maxwellian distribution. This inconsistency may be due to the effect of thermal radiation Yarkovsky--O'Keefe--Radzievskii--Paddack (YORP) torques, and implies that the collision event that formed V-type asteroids is sub-billion to several billion years in age.

  1. Mitigation of Hazardous Comets and Asteroids

    Science.gov (United States)

    Belton, Michael J. S.; Morgan, Thomas H.; Samarasinha, Nalin H.; Yeomans, Donald K.

    2011-03-01

    Preface; 1. Recent progress in interpreting the nature of the near-Earth object population W. Bottke, A. Morbidelli and R. Jedicke; 2. Earth impactors: orbital characteristics and warning times S. R. Chesley and T. B. Spahr; 3. The role of radar in predicting and preventing asteroid and comet collisions with Earth S. J. Ostro and J. D. Giorgini; 4. Interior structures for asteroids and cometary nuclei E. Asphaug; 5. What we know and don't know about surfaces of potentially hazardous small bodies C. R. Chapman; 6. About deflecting asteroids and comets K. A. Holsapple; 7. Scientific requirements for understanding the near-Earth asteroid population A. W. Harris; 8. Physical properties of comets and asteroids inferred from fireball observations M. D. Martino and A. Cellino; 9. Mitigation technologies and their requirements C. Gritzner and R. Kahle; 10. Peering inside near-Earth objects with radio tomography W. Kofman and A. Safaeinili; 11. Seismological imvestigation of asteroid and comet interiors J. D. Walker and W. F. Huebner; 12. Lander and penetrator science for near-Earth object mitigation studies A. J. Ball, P. Lognonne, K. Seiferlin, M. Patzold and T. Spohn; 13. Optimal interpretation and deflection of Earth-approaching asteroids using low-thrust electric propulsion B. A. Conway; 14. Close proximity operations at small bodies: orbiting, hovering, and hopping D. J. Scheeres; 15. Mission operations in low gravity regolith and dust D. Sears, M. Franzen, S. Moore, S. Nichols, M. Kareev and P. Benoit; 16. Impacts and the public: communicating the nature of the impact hazard D. Morrison, C. R. Chapman, D. Steel and R. P. Binzel; 17. Towards a program to remove the threat of hazardous NEOs M. J. S. Belton.

  2. Using Dust from Asteroids as Regolith Microsamples

    Science.gov (United States)

    Cohen, B. A.; Klima, Rachel; Chabot, N. L.; Rivkin, A. S.

    2015-01-01

    Meteorite science is rich with compositional indicators by which we classify parent bodies, but few sample groups are definitively linked with asteroid spectra. More robust links need to be forged between meteorites and their parent bodies to understand the composition, diversity and distribution. A major link can be sample analysis of the parent body material and comparison with meteorite data. Hayabusa, the first sample return mission of the Japanese Aerospace Exploration Agency (JAXA), was developed to rendezvous with and collect samples from asteroid Itokawa and return them to Earth. Thousands of sub-100 micron particles were recovered, apparently introduced during the spacecraft impact into the surface of the asteroid, linking the asteroid Itokawa to LL chondrites [1]. Upcoming missions Hayabusa 2 and OSIRIS-REx will collect more significant sample masses from asteroids. In all these cases, the samples are or will be a collection of regolith particles. Sample return to earth is not the only method for regolith particle analysis. Dust is present around all airless bodies, generated by micrometeorite impact into their airless surfaces, which in turn lofts regolith particles into a "cloud" around the body. The composition, flux, and size-frequency distribution of dust particles can provide significant insight into the geological evolution of airless bodies [2]. For example, the Cassini Cosmic Dust Analyzer (CDA) detected salts in Enceladus' icy plume material, providing evidence for a subsurface ocean in contact with a silicate seafloor [3]. Similar instruments have flown on the Rosetta, LADEE, and Stardust missions. Such an instrument may be of great use in obtaining the elemental, isotopic and mineralogical composition measurement of dust particles originating from asteroids without returning the samples to terrestrial laboratories. We investigated the ability of a limited sample analysis capability using a dust instrument to forge links between asteroid

  3. Aqueous alteration on main-belt asteroids

    Science.gov (United States)

    Fornasier, S.; Lantz, C.; Barucci, M.; Lazzarin, M.

    2014-07-01

    The study of aqueous alteration is particularly important for unraveling the processes occurring during the earliest times in Solar System history, as it can give information both on the thermal processes and on the localization of water sources in the asteroid belt, and for the associated astrobiological implications. The aqueous alteration process produces the low temperature (< 320 K) chemical alteration of materials by liquid water which acts as a solvent and produces materials like phyllosilicates, sulphates, oxides, carbonates, and hydroxides. This means that liquid water was present in the primordial asteroids, produced by the melting of water ice by heating sources, very probably by ^{26}Al decay. Hydrated minerals have been found mainly on Mars surface, on primitive main-belt asteroids (C, G, B, F, and P-type, following the classification scheme by Tholen, 1984) and possibly also on few transneptunian objects. Reflectance spectroscopy of aqueous altered asteroids shows absorption features in the 0.6-0.9 and 2.5-3.5-micron regions, which are diagnostic of, or associated with, hydrated minerals. In this work, we investigate the aqueous alteration process on a large sample of 600 visible spectra of C-complex asteroids available in the literature. We analyzed all these spectra in a similar way to characterize the absorption-band parameters (band center, depth, and width) and spectral slope, and to look for possible correlations between the aqueous alteration process and the asteroids taxonomic classes, orbital elements, heliocentric distances, albedo, and sizes. We find that 4.6 % of P, 7.7 % of F, 9.8 % of B, 50.5 % of C, and 100 % of the G-type asteroids have absorption bands in the visible region due to hydrated silicates. Our analysis shows that the aqueous alteration sequence starts from the P-type objects, practically unaltered, and increases through the P → F → B → C → G asteroids, these last being widely aqueously altered, strengthening thus

  4. A Search for Asteroids, Moons, and Rings Orbiting White Dwarfs

    CERN Document Server

    Di Stefano, Rosanne; Kawaler, Steven D

    2009-01-01

    Do white dwarfs host asteroid systems? Although several lines of argument suggest that white dwarfs may be orbited by large populations of asteroids, transits would provide the most direct evidence. We demonstrate that the Kepler mission has the capability to detect transits of white dwarfs by asteroids. Because white-dwarf asteroid systems, if they exist, are likely to contain many asteroids orbiting in a spatially extended distribution, discoveries of asteroid transits can be made by monitoring only a small number of white dwarfs, compatible with Kepler's primary mission, which is to monitor stars with potentially habitable planets. Possible future missions that survey ten times as many stars with similar sensitivity and minute-cadence monitoring can establish the characteristics of asteroid systems around white dwarfs, such as the distribution of asteroid sizes and semimajor axes. Transits by planets would be more dramatic, but the probability that they will occur is lower. Ensembles of planetary moons and...

  5. A Fast Ellipsoid Model for Asteroids Inverted From Lightcurves

    CERN Document Server

    Lu, Xiaoping; You, Zhong

    2012-01-01

    The research about asteroids attracts more and more attention recently, especially focusing on their physical structures, such as the spin axis, the rotation period and the shape. The long distance between Earth observers and asteroids makes it impossible to get the shape and other parameters of asteroids directly with the exception of the NEAs (Near Earth Asteroids) and others passed by some spacecrafts. Generally photometric measurement is still the main way to obtain the research data for asteroids now, i.e. the lightcurves recording the brightness and positions of asteroids. Supposing that the shape of the asteroid is a triaxial ellipsoid with a stable spinning status, a new method is present in this article to reconstruct the shape models of asteroids from the lightcurves, with the other physical parameters together. By applying a special curvature function, the method calculates the brightness integration on a unit sphere and Lebedev Quadrature is employed for the discretization. At last the method sear...

  6. Human Robotic Systems (HRS): Robotic Technologies for Asteroid Missions Element

    Data.gov (United States)

    National Aeronautics and Space Administration — During 2014, the Robotic Technologies for Asteroid Missions activity has four tasks:Asteroid Retrieval Capture Mechanism Development and Testbed;Mission Operations...

  7. Thermal Tomography of Asteroid Surface Structure

    CERN Document Server

    Harris, Alan

    2016-01-01

    Knowledge of the surface thermal inertia of an asteroid can provide insight into surface structure: porous material has a lower thermal inertia than rock. We develop a means to estimate thermal inertia values of asteroids and use it to show that thermal inertia appears to increase with spin period in the case of main-belt asteroids (MBAs). Similar behavior is found on the basis of thermophysical modeling for near-Earth objects (NEOs). We interpret our results in terms of rapidly increasing material density and thermal conductivity with depth, and provide evidence that thermal inertia increases by factors of 10 (MBAs) to 20 (NEOs) within a depth of just 10 cm. Our results are consistent with a very general picture of rapidly changing material properties in the topmost regolith layers of asteroids and have important implications for calculations of the Yarkovsky effect, including its perturbation of the orbits of potentially hazardous objects and those of asteroid family members after the break-up event. Eviden...

  8. Search for a Differentiated Asteroid Family

    Science.gov (United States)

    Thomas, Cristina A.; Lim, Lucy F.; Trilling, David E.; Moskovitz, Nicholas

    2014-08-01

    Dynamical asteroid families resulting from catastrophic disruptions represent the interiors of their former parent bodies. Differentiation of a large initially chondritic parent body is expected to produce an ``onion shell" object with a metal core, a thick olivine-rich mantle, and a thin basaltic crust. However, instead of the mineralogical diversity expected from the disruption of a differentiated parent body, most asteroid families tend to show similar spectra among the members. Moreover, spectra of metal-like materials and olivine-dominated assemblages have not been detected in asteroid families in the Main Belt and the expected mantle material is missing from the meteorite record. The deficit of olivine-rich mantle material in the meteorite record and in asteroid observations is known as the ``Missing Mantle" problem. For years the best explanation for the lack of mantle material has been the ``battered to bits" hypothesis that states that all differentiated parent bodies (aside from Vesta) were disrupted very early in the solar system and the resulting olivine-rich material was collisionally broken down until the object diameters fell below our observational limits. However, in a new, competing, hypothesis, Elkins-Tanton et al. (2013) has suggested that previous work has overestimated the amount of olivine produced by the differentiation of a chondritic parent body. We propose to obtain visible spectra of asteroids within the Massalia, Merxia, and Agnia S-type families to search for compositional variations that are indicators of differentiation and to quantitatively constrain the two competing ``Missing Mantle" hypotheses.

  9. Rotational properties of Maria asteroid family

    CERN Document Server

    Kim, Myung-Jin; Moon, Hong-Kyu; Byun, Yong-Ik; Brosch, Noah; Kaplan, Murat; Kaynar, Suleyman; Uysal, Omer; Guzel, Eda; Behrend, Raoul; Yoon, Joh-Na; Mottola, Stefano; Hellmich, Stephan; Hinse, Tobias C; Eker, Zeki; Park, Jang-Hyun

    2013-01-01

    Maria family is regarded as an old-type (~3 +/- 1 Gyr) asteroid family which has experienced substantial collisional and dynamical evolution in the Main-belt. It is located nearby the 3:1 Jupter mean motion resonance area that supplies Near-Earth asteroids (NEAs) to the inner Solar System. We carried out observations of Maria family asteroids during 134 nights from 2008 July to 2013 May, and derived synodic rotational periods for 51 objects, including newly obtained periods of 34 asteroids. We found that there is a significant excess of fast and slow rotators in observed rotation rate distribution. The two-sample Kolmogorov-Smirnov test confirms that the spin rate distribution is not consistent with a Maxwellian at a 92% confidence level. From correlations among rotational periods, amplitudes of lightcurves, and sizes, we conclude that the rotational properties of Maria family asteroids have been changed considerably by non-gravitational forces such as the YORP effect. Using a lightcurve inversion method (Kaa...

  10. The Dynamical Evolution of the Asteroid Belt

    CERN Document Server

    Morbidelli, Alessandro; O'Brien, David P; Minton, David A; Bottke, William F

    2015-01-01

    The asteroid belt is the leftover of the original planetesimal population in the inner solar system. However, currently the asteroids have orbits with all possible values of eccentricities and inclinations compatible with long-term dynamical stability, whereas the initial planetesimal orbits should have been quasi-circular and almost co-planar. The total mass in the asteroid population is a small fraction of that existing primordially. Also, asteroids with different chemical/mineralogical properties are not ranked in an orderly manner with mean heliocentric distance as one could expect from the existence of a radial gradient of the temperature in the proto-planetary disk, but they are partially mixed. These properties show that the asteroid belt has been severely sculpted by one or a series of processes during its lifetime. This paper reviews the processes that have been proposed so far, discussing the properties that they explain and the problems that they are confronted with. Emphasis is paid to the interpl...

  11. Thermal Tomography of Asteroid Surface Structure

    Science.gov (United States)

    Harris, Alan W.; Drube, Line

    2016-12-01

    Knowledge of the surface thermal inertia of an asteroid can provide insight into its surface structure: porous material has a lower thermal inertia than rock. We develop a means to estimate thermal inertia values of asteroids and use it to show that thermal inertia appears to increase with spin period in the case of main-belt asteroids (MBAs). Similar behavior is found on the basis of thermophysical modeling for near-Earth objects (NEOs). We interpret our results in terms of rapidly increasing material density and thermal conductivity with depth, and provide evidence that thermal inertia increases by factors of 10 (MBAs) to 20 (NEOs) within a depth of just 10 cm. Our results are consistent with a very general picture of rapidly changing material properties in the topmost regolith layers of asteroids and have important implications for calculations of the Yarkovsky effect, including its perturbation of the orbits of potentially hazardous objects and those of asteroid family members after the break-up event. Evidence of a rapid increase of thermal inertia with depth is also an important result for studies of the ejecta-enhanced momentum transfer of impacting vehicles (“kinetic impactors”) in planetary defense.

  12. On the Discovery of the Asteroid 3784 Chopin

    Science.gov (United States)

    Elst, E. W.

    Le 31 octobre 1986 lords d'une campagne de recherche d'asteroides a l'observatoire de Haute Provence, un asteroide de septieme magnitude fut decouvert. A l'occasion de l'opposition consecutive en 1988, l'asteroide fut observe a nouveau a l'observatoire de Haute Provence, ce qui entraina la numerotation definitive. L'asteroide recoit le numero 3874 et le nom du grand compositeur polonais, Chopin.

  13. Space Rocks: A Series of Papers on Meteorites and Asteroids

    OpenAIRE

    Hooper, Nina Louise

    2016-01-01

    The subject of this work is the compositions of asteroids and meteorites. Studies of the composition of small Solar System bodies are fundamental to theories of planet formation. Meteorites, samples available for analysis in the lab, help constrain the timeline and conditions in the early Solar System. Asteroid reflectance spectra help define the links between asteroids and meteorites. Studies of the spectral types and sizes of asteroids test dynamical models. These studie...

  14. Characterization of the near-Earth Asteroid 2002NY40

    OpenAIRE

    Roberts, Jr., Lewis C.; Hall, Doyle T.; Lambert, John V.; Africano, John L.; Knox, Keith T.; Barros, Jacob K.; Hamada, Kris M.; Liang, Dennis; Sydney, Paul F.; Kervin, Paul

    2007-01-01

    In August 2002, the near-Earth asteroid 2002 NY40, made its closest approach to the Earth. This provided an opportunity to study a near-Earth asteroid with a variety of instruments. Several of the telescopes at the Maui Space Surveillance System were trained at the asteroid and collected adaptive optics images, photometry and spectroscopy. Analysis of the imagery reveals the asteroid is triangular shaped with significant self-shadowing. The photometry reveals a 20-hour period and the spectros...

  15. Asteroid Redirect Mission Proximity Operations for Reference Target Asteroid 2008 EV5

    Science.gov (United States)

    Reeves, David M.; Mazanek, Daniel D.; Cichy, Benjamin D.; Broschart, Steve B.; Deweese, Keith D.

    2016-01-01

    NASA's Asteroid Redirect Mission (ARM) is composed of two segments, the Asteroid Redirect Robotic Mission (ARRM), and the Asteroid Redirect Crewed Mission (ARCM). In March of 2015, NASA selected the Robotic Boulder Capture Option1 as the baseline for the ARRM. This option will capture a multi-ton boulder, (typically 2-4 meters in size) from the surface of a large (greater than approx.100 m diameter) Near-Earth Asteroid (NEA) and return it to cis-lunar space for subsequent human exploration during the ARCM. Further human and robotic missions to the asteroidal material would also be facilitated by its return to cis-lunar space. In addition, prior to departing the asteroid, the Asteroid Redirect Vehicle (ARV) will perform a demonstration of the Enhanced Gravity Tractor (EGT) planetary defense technique2. This paper will discuss the proximity operations which have been broken into three phases: Approach and Characterization, Boulder Capture, and Planetary Defense Demonstration. Each of these phases has been analyzed for the ARRM reference target, 2008 EV5, and a detailed baseline operations concept has been developed.

  16. Asteroid Impact and Deflection Assessment mission: the Double Asteroid Redirection Test (DART)

    Science.gov (United States)

    Cheng, A.; Michel, P.

    2015-10-01

    The Asteroid Impact & Deflection Assessment (AIDA) mission will be the first space experiment to demonstrate asteroid impact hazard mitigation by using a kinetic impactor. AIDA is a joint ESA-NASA cooperative project, which includes the ESA Asteroid Impact Mission (AIM) rendezvous spacecraft and the NASA Double Asteroid Redirection Test (DART) mission. The AIDA target is the near-Earth binary asteroid 65803 Didymos, which will make an unusually close approach to Earth in October, 2022. The ~300-kg DART spacecraft is designed to impact the Didymos secondary at 6.5 km/s and demonstrate the ability to modify its trajectory through momentum transfer. The primary goals of AIDA are (i) to investigate the binary near-Earth asteroid (65803) Didymos, (ii) to demonstrate asteroid deflection by kinetic impact and to characterize the deflection. The primary DART objectives are to demonstrate a hypervelocity impact on the Didymos moon and to determine the resulting deflection from ground-based observatories. The DART impact on the Didymos secondary will cause a measurable change in the orbital period of the binary.

  17. GEODSS Tracking Results on Asteroid 2012 DA14

    Science.gov (United States)

    2013-06-12

    GEODSS Tracking Results on Asteroid 2012 DA14...Abstract The potential effects of an asteroid passing within close proximity to the Earth...were recently realized During the February 16, 2013 event, Asteroid 2012 DA14 passed within an estimated 27,700 kilometers of the earth, well

  18. Ivar asteroid rendezvous mission system scenario and trajectory design

    Institute of Scientific and Technical Information of China (English)

    崔平远; 李立涛; 崔祜涛; 栾恩杰; 吴伟仁; 田玉龙

    2003-01-01

    The asteroid exploration opportunities are searched and calculated with launch dates in 2006 to2010, and with asteroid Ivar 1627 as the target, the spacecraft and its subsystems are designed and analyzed,and the transfer trajectory is designed using △VEGA technology for the asteroid rendezvous. The design resultssatisfied the energy requirements for small explorers.

  19. Close Approaches of Potentially Hazardous Asteroids during Two Centuries

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Asteroids are the most important small bodies in the solar system and the near-earth asteroids (NEAs) are of especial concern to the world. The reasonis that they will make close approaches to the earth in the near future. We usea reasonable dynamical model and an efficient computing method to calculate the orbits of over 160 Potentially Hazardous Asteroids (PHAs) for two centuries.

  20. Determination of pole orientations and shapes of asteroids

    Science.gov (United States)

    Magnusson, Per; Barucci, M. Antonietta; Drummond, Jack D.; Lumme, Kari; Ostro, Steven J.

    1989-01-01

    The principles of asteroid light-curve inversion are discussed together with basic principles involved in approaches for deriving asteroid pole and shape parameters from photometry data. The merits of various pole determination techniques are described and compared. Results obtained so far on the pole orientations and shapes of asteroids are presented.

  1. AIDA: the Asteroid Impact & Deflection Assessment mission

    Science.gov (United States)

    Vincent, Jean-Baptiste

    2016-07-01

    The Asteroid Impact & Deflection Assessment (AIDA) mission is a joint cooperation between European and US space agencies that consists of two separate and independent spacecraft that will be launched to a binary asteroid system, the near-Earth asteroid Didymos, to assess the possibility of deflecting an asteroid trajectory by using a kinetic impactor. The European Asteroid Impact Mission (AIM) is under Phase A/B1 study at ESA from March 2015 until summer 2016. AIM is set to rendez-vous with the asteroid system a few months prior to the impact by the US Double Asteroid Redirection Test (DART) spacecraft to fully characterize the smaller of the two binary components. AIM is a unique mission as it will be the first time that a spacecraft will investigate the surface, subsurface, and internal properties of a small binary near Earth asteroid. In addition it will perform various important technology demonstrations that can serve other space missions: AIM will release a set of CubeSats in deep space and a lander on the surface of the smaller asteroid and for the first time, deep-space inter-satellite linking will be demonstrated between the main spacecraft, the CubeSats, and the lander, and data will also be transmitted from interplanetary space to Earth by a laser communication system. The knowledge obtained by this mission will have great implications for our understanding of the history of the Solar System. Small asteroids are believed to result from collisions and other processes (e.g., spinup, shaking) that made them what they are now. Having direct information on their surface and internal properties will allow us to understand how these processes work and transform these small bodies as well as, for this particular case, how a binary system forms. So far, our understanding of the collisional process and the validation of numerical simulations of the impact process rely on impact experiments at laboratory scales. With DART, thanks to the characterization of the

  2. The Potentially Dangerous Asteroid (101955 Bennu

    Directory of Open Access Journals (Sweden)

    I. Włodarczyk

    2014-01-01

    searching for close approaches with the earth, which can lead to possible impacts up to 2200. With the A2 nongravitational parameter in the motion of the asteroid (101955 Bennu we computed possible impact solutions using different JPL planetary and lunar ephemerides and different number of additional massive perturbed asteroids. The possible impact path of risk for 2175 is presented. Additionally, we computed possible impact solutions using the normal places method of the selection of Bennu’s astrometric observations. Moreover, we computed time evolution of the mean orbital elements and the orbital nodes of Bennu 5 kyr in the backwards and 1 kyr in the future using the Yarkovsky effects. We computed the mean motion and secular orbital resonances of the Bennu. We also computed the influence of the JPL planetary and lunar ephemerides DE403, DE405, DE406, DE414, and DE423 on the close approaches of the asteroid (101955 Bennu with the earth.

  3. Measurement of Cohesion in Asteroid Regolith Materials

    Science.gov (United States)

    Kleinhenz, Julie E.; Gaier, James R.; Waters, Deborah L.; Harvey, Ralph; Zeszut, Zoe; Carreno, Brandon; Shober, Patrick

    2017-01-01

    A study has been initiated to examine cohesive forces in asteroid materials to contribute to a better understanding of low density bodies such as asteroids and Phobos, and assist in exploration missions involving interaction with their surface material. The test specimen used in this study was a lightly weathered CM2 meteorite which is spectroscopically similar to Type C (carbonaceous) asteroids, and thought to have representative surface chemistry. To account for sample heterogeneity, adhesion forces were measured between the CM2 sample and its five primary mineral phase components. These adhesive forces bound the range of cohesive force that can be expected for the bulk material. All materials were characterized using a variety of optical and spectroscopic methods. Adhesive forces on the order of 50 to 400 µN were measured using a torsion balance in an ultrahigh vacuum chamber. The mineral samples exhibited clearly different adhesive strengths in the following hierarchy: Serpentine > Siderite > Bronzite > Olivine ˜ Fe-Ni.

  4. Defining a successful commercial asteroid mining program

    Science.gov (United States)

    Andrews, Dana G.; Bonner, K. D.; Butterworth, A. W.; Calvert, H. R.; Dagang, B. R. H.; Dimond, K. J.; Eckenroth, L. G.; Erickson, J. M.; Gilbertson, B. A.; Gompertz, N. R.; Igbinosun, O. J.; Ip, T. J.; Khan, B. H.; Marquez, S. L.; Neilson, N. M.; Parker, C. O.; Ransom, E. H.; Reeve, B. W.; Robinson, T. L.; Rogers, M.; Schuh, P. M.; Tom, C. J.; Wall, S. E.; Watanabe, N.; Yoo, C. J.

    2015-03-01

    This paper summarizes a commercial Asteroid Mining Architecture synthesized by the Senior Space Design Class at the University of Washington in Winter/Spring Quarters of 2013. The main author was the instructor for that class. These results use design-to-cost development methods and focused infrastructure advancements to identify and characterize a workable space industrialization architecture including space transportation elements, asteroid exploration and mining equipment, and the earth orbit infrastructure needed to make it all work. Cost analysis predicts that for an initial investment in time and money equivalent to that for the US North Slope Oil Field, the yearly world supply of Platinum Group Metals could be increased by 50%, roughly 1500 t of LOX/LH2 propellant/year would be available in LEO, and very low cost solar panels could be assembled at GEO using asteroidal materials. The investment also would have a discounted net present value return on investment of 22% over twenty years.

  5. Rock legends the asteroids and their discoverers

    CERN Document Server

    Murdin, Paul

    2016-01-01

    This book relates the history of asteroid discoveries and christenings, from those of the early pioneering giants of Hersehel and Piazzi to modern-day amateurs. Moving from history and anecdotal information to science, the book's structure is provided by the names of the asteroids, including one named after the author. Free from a need to conform to scientific naming conventions, the names evidence hero-worship, sycophancy, avarice, vanity, whimsy, erudition and wit, revealing the human side of astronomers, especially where controversy has followed the christening. Murdin draws from extensive historical records to explore the debate over these names. Each age reveals its own biases and preferences in the naming process. < Originally regarded as “vermin of the skies,” asteroids are minor planets, rocky scraps left over from the formation of the larger planets, or broken fragments of worlds that have collided. Their scientific classification as “minor” planets makes them seem unimportant, but over th...

  6. SNC meteorites - Evidence against an asteroidal origin

    Science.gov (United States)

    Ashwal, L. D.; Warner, J. L.; Wood, C. A.

    1982-01-01

    About 1.3 billion years ago, on one or more distant planetary bodies, silicate melts formed and produced cumulate rocks which eventually made their way to earth. Nine of these rocks have been recovered. Three distinct groups are involved, including shergottites, nakhlites, and chassignites (abbreviated as SNC). The young crystallization ages and other chemical features of SNC meteorites have prompted several workers to suggest that the specimens may be samples of igneous rock, ejected from the surface of Mars during an impact event. Others have rejected the Martian origin of SNC meteorites in favor of a more traditional asteroidal parent body. The present investigation shows that the petrologic, geochemical, and isotopic evidence is inconsistent with an asteroidal origin for SNC meteorites. It is found that the characteristics of SNC meteorites argue convincingly against their origin in a planetary object as small as the largest asteroid. That these meteorites may be fragments of the Martian surface still remains the most likely possibility.

  7. A Proposed Unified Theory of Hydrated Asteroids

    Science.gov (United States)

    Rivkin, Andrew S.

    2016-10-01

    The last decade has seen tremendous growth in the study of hydrated and hydroxylated minerals (hereafter simply called "hydrated minerals") on asteroids. Several workers have used absorptions in the 3-µm region and a correlated absorption near 0.7 µm to determine not only the presence or absence of these minerals but gain insight into the compositions of asteroid surfaces. Spectra of hundreds of asteroids have been measured and published or presented at meetings, and we are in a position to use these newer datasets to globally assess the patterns and relationships we see, as previously done by Jones et al. (1990) and Takir et al. (2012). There are several points to be addressed by any such assessment. Several different band shapes are seen in the 3-µm region, only one of which is seen in the hydrated meteorites in our collections. However, each of the main 3-µm band shapes is represented among parent bodies of collisional families. There seems to be little correlation in general between asteroid spectral class and 3-µm band shape, save for the Ch meteorites which are overwhelmingly likely to share the same band shape as the CM meteorites. Ceres has an unusual but not unique band shape, which has thus far only been found on the largest asteroids. I will present an outline scenario for the formation and evolution of hydrated asteroids, where aqueous alteration serves to lithify some objects while other objects remain unlithified and still others differentiate and suffer collisional modification. While some details will no doubt be altered to account for better or new information, this scenario is offered as a starting point for discussion.

  8. Orbital Mechanics near a Rotating Asteroid

    Indian Academy of Sciences (India)

    Yu Jiang; Hexi Baoyin

    2014-03-01

    This study investigates the different novel forms of the dynamical equations of a particle orbiting a rotating asteroid and the effective potential, the Jacobi integral, etc. on different manifolds. Nine new forms of the dynamical equations of a particle orbiting a rotating asteroid are presented, and the classical form of the dynamical equations has also been found. The dynamical equations with the potential and the effective potential in scalar form in the arbitrary body-fixed frame and the special body-fixed frame are presented and discussed. Moreover, the simplified forms of the effective potential and the Jacobi integral have been derived. The dynamical equation in coefficient-matrix form has been derived. Other forms of the dynamical equations near the asteroid are presented and discussed, including the Lagrange form, the Hamilton form, the symplectic form, the Poisson form, the Poisson-bracket form, the cohomology form, and the dynamical equations on Kähler manifold and another complex manifold. Novel forms of the effective potential and the Jacobi integral are also presented. The dynamical equations in scalar form and coefficient-matrix form can aid in the study of the dynamical system, the bifurcation, and the chaotic motion of the orbital dynamics of a particle near a rotating asteroid. The dynamical equations of a particle near a rotating asteroid are presented on several manifolds, including the symplectic manifold, the Poisson manifold, and complex manifolds, which may lead to novel methods of studying the motion of a particle in the potential field of a rotating asteroid.

  9. Rotational properties of the Maria asteroid family

    Science.gov (United States)

    Kim, M.; Choi, Y.; Moon, H.; Byun, Y.; Brosch, N.; Kaplan, M.; Kaynar, S.; Uysal, O.; Guzel, E.; Behrend, R.; Yoon, J.; Mottola, S.; Hellmich, S.; Hinse, T.; Eker, Z.; Park, J.

    2014-07-01

    Introduction: The Maria family is regarded as an old-type (˜3 ± 1 Gyr) [1] asteroid family which has experienced substantial collisional and dynamical evolution in the main belt. It is located near the 3:1 Jupiter mean-motion resonance area that supplies near-Earth asteroids (NEAs) to the inner Solar System. Observations: We carried out observations of Maria family asteroids in 134 nights from July 2008 to May 2013 using 0.5-m to 2-m class telescopes at seven observatories in the northern hemisphere, and derived synodic rotational periods for 51 objects, including new periods for 34 asteroids [2]. Results: We found that there is a significant excess of fast and slow rotators in the observed rotation-rate distribution. From the correlations among rotational periods, the amplitudes of lightcurves, and the sizes, we conclude that the rotational properties of the Maria family asteroids have been changed considerably by non-gravitational forces such as the YORP effect. Using the lightcurve inversion method [3,4], we successfully determined pole orientations for 13 Maria members, and found an excess of prograde spins over retrograde spins with a ratio (N_p/N_r) of 3. This implies that the retrograde rotators could have been ejected by the 3:1 resonance into the inner Solar System since the formation of the Maria family. We estimate that approximately 37 to 75 Maria family asteroids larger than 1 km have entered the near-Earth space as per 100 Myr [2].

  10. Asteroid families - Physical properties and evolution

    Science.gov (United States)

    Chapman, Clark R.; Paolicchi, Paolo; Zappala, Vincenzo; Binzel, Richard P.; Bell, Jeffrey F.

    1989-01-01

    Asteroid families are considered to be fragments from collisional destruction of precursor bodies. However, results available on the inferred mineralogy, size distributions, and spins of family members do not confirm the expectations of the traditional model. Only a handful of nearly 100 proposed families, most of them populous, have distributions of inferred mineralogies consistent with simple cosmochemical models for parent bodies. It is suggested that most catastrophic collisions may not result in observable families, but rather in a spray of smaller particles, thus accounting for the small number of confirmed and consistent families, despite evidence for extensive collisional evolution of asteroids.

  11. Asteroidal Quadruples in non Rooted Path Graphs

    Directory of Open Access Journals (Sweden)

    Gutierrez Marisa

    2015-11-01

    Full Text Available A directed path graph is the intersection graph of a family of directed subpaths of a directed tree. A rooted path graph is the intersection graph of a family of directed subpaths of a rooted tree. Rooted path graphs are directed path graphs. Several characterizations are known for directed path graphs: one by forbidden induced subgraphs and one by forbidden asteroids. It is an open problem to find such characterizations for rooted path graphs. For this purpose, we are studying in this paper directed path graphs that are non rooted path graphs. We prove that such graphs always contain an asteroidal quadruple.

  12. Gravitational Capture of Asteroids by Gas Drag

    Directory of Open Access Journals (Sweden)

    E. Vieira Neto

    2009-01-01

    captured by the planet got its velocity reduced and could been trapped as an irregular satellite. It is well known that, depending on the time scale of the gas envelope, an asteroid will spiral and collide with the planet. So, we simulate the passage of the asteroid in the gas envelope with its density decreasing along the time. Using this approach, we found effective captures, and have a better understanding of the whole process. Finally, we conclude that the origin of the irregular satellites cannot be attributed to the gas drag capture mechanism alone.

  13. The Bering small vehicle asteroid mission concept

    DEFF Research Database (Denmark)

    Michelsen, Rene; Andersen, Anja; Haack, Henning

    2004-01-01

    The study of asteroids is traditionally performed by means of large Earth based telescopes, by means of which orbital elements and spectral properties are acquired. Space borne research, has so far been limited to a few occasional flybys and a couple of dedicated flights to a single selected target...... targets. The dilemma obviously being the resolution versus distance and the statistics versus DeltaV requirements. Using advanced instrumentation and onboard autonomy, we have developed a space mission concept whose goal is to map the flux, size, and taxonomy distributions of asteroids. The main focus...

  14. Manuel′s asteroid disruption technique

    Directory of Open Access Journals (Sweden)

    Manuel John

    2015-01-01

    Full Text Available A seventy-year-old male presented with dense asteroid hyalosis in both eyes. He had undergone cataract extraction in one eye 3 years ago, and the other eye had immature cataract. Both the autorefractor and dilated streak retinoscopy did not give readings and subjective visual improvement could not be achieved. Immediately following YAG posterior capsulotomy and anterior vitreous asteroid disruption, the vision improved to 20/20 with recordable auto refractor and streak retinoscopy values. Our initial experience indicates that the treatment is simple, safe and effective but needs controlled and prospective studies to confirm its long-term safety.

  15. Collisional evolution of the early asteroid belt

    Science.gov (United States)

    Gil-Hutton, Ricardo; Brunini, Adrián

    1999-04-01

    We present numerical results obtained by a simulation of the collisional process between asteroids and scattered comets from the Uranus-Neptune zone. This mechanism allows the use of single exponent incremental size distributions for the initial belt reaching a final distribution that matches the observed population very well. Since the cometary bombardment was extremely efficient removing mass from the primordial asteroid belt in a very short time, we always obtained belts with total masses less than 0.001 M ⊕ after ≈ 2×10 7 yrs. This result allows processes with an important initial mass preserving Vestas basaltic crust.

  16. Capturing near-Earth asteroids around Earth

    Science.gov (United States)

    Hasnain, Zaki; Lamb, Christopher A.; Ross, Shane D.

    2012-12-01

    The list of detected near-Earth asteroids (NEAs) is constantly growing. NEAs are likely targets for resources to support space industrialization, as they may be the least expensive source of certain needed raw materials. The limited supply of precious metals and semiconducting elements on Earth may be supplemented or even replaced by the reserves floating in the form of asteroids around the solar system. Precious metals make up a significant fraction NEAs by mass, and even one metallic asteroid of ˜1km size and fair enrichment in platinum-group metals would contain twice the tonnage of such metals already harvested on Earth. There are ˜1000 NEAs with a diameter of greater than 1 km. Capturing these asteroids around the Earth would expand the mining industry into an entirely new dimension. Having such resources within easy reach in Earth's orbit could provide an off-world environmentally friendly remedy for impending terrestrial shortages, especially given the need for raw materials in developing nations. In this paper, we develop and implement a conceptually simple algorithm to determine trajectory characteristics necessary to move NEAs into capture orbits around the Earth. Altered trajectories of asteroids are calculated using an ephemeris model. Only asteroids of eccentricity less than 0.1 have been studied and the model is restricted to the ecliptic plane for simplicity. We constrain the time of retrieval to be 10 years or less, based on considerations of the time to return on investment. For the heliocentric phase, constant acceleration is assumed. The acceleration required for transporting these asteroids from their undisturbed orbits to the sphere of influence of the Earth is the primary output, along with the impulse or acceleration necessary to effect capture to a bound orbit once the Earth's sphere of influence is reached. The initial guess for the constant acceleration is provided by a new estimation method, similar in spirit to Edelbaum's. Based on the

  17. NASA's Asteroid Redirect Mission: Overview and Status

    Science.gov (United States)

    Abell, Paul; Gates, Michele; Johnson, Lindley; Chodas, Paul; Brophy, John; Mazanek, Dan; Muirhead, Brian

    A major element of the National Aeronautics and Space Administration’s (NASA) new Asteroid Initiative is the Asteroid Redirect Mission (ARM). This concept was first proposed in 2011 during a feasibility study at the Keck Institute for Space Studies (KISS)[1] and is under consideration for implementation by NASA. The ARM involves sending a high-efficiency (ISP 3000 s), high-power (40 kW) solar electric propulsion (SEP) robotic vehicle that leverages technology developed by NASA’s Space Technology Mission Directorate (STMD) to rendezvous with a near-Earth asteroid (NEA) and return asteroidal material to a stable lunar distant retrograde orbit (LDRO)[2]. There are two mission concepts currently under study, one that captures an entire 7 - 10 meter mean diameter NEA[3], and another that retrieves a 1 - 10 meter mean diameter boulder from a 100+ meter class NEA[4]. Once the retrieved asteroidal material is placed into the LDRO, a two person crew would launch aboard an Orion capsule to rendezvous and dock with the robotic SEP vehicle. After docking, the crew would conduct two extra-vehicular activities (EVA) to collect asteroid samples and deploy instruments prior to Earth return. The crewed portion of the mission is expected to last approximately 25 days and would represent the first human exploration mission beyond low-Earth orbit (LEO) since the Apollo program. The ARM concept leverages NASA’s activities in Human Exploration, Space Technology, and Planetary Defense to accomplish three primary objectives and several secondary objectives. The primary objective relevant to Human Exploration is to gain operational experience with vehicles, systems, and components that will be utilized for future deep space exploration. In regard to Space Technology, the ARM utilizes advanced SEP technology that has high power and long duration capabilities that enable future missions to deep space destinations, such as the Martian system. With respect to Planetary Defense, the ARM

  18. Failure mode diagram of rubble pile asteroids: Application to (25143) asteroid Itokawa

    Science.gov (United States)

    Hirabayashi, Masatoshi; Scheeres, Daniel J.

    2016-01-01

    Proposing a diagram which shows the variation in asteroidal failure as a function of a spin period, later called the failure mode diagram, this paper considers the failure modes and conditions of asteroid (25143) Itokawa. This diagram is useful to describe when and where failure occurs in an asteroid. Assuming that Itokawa is homogeneous, we use a plastic finite element code to obtain the diagram for this object. The results show that if the bulk cohesive strength is less than 0.1 Pa, Itokawa experiences compressional failure on the neck surface at the current spin period 12.1 hours. At a spin period shorter than 4.5 hours, tension across the neck causes this asteroid to split into two components. It is also found that if the breakup spin period is longer than 5.2 hours, their motion is bounded. This implies that once Itokawa splits, the components may escape from one another.

  19. Asteroid mass estimation using Markov-Chain Monte Carlo techniques

    Science.gov (United States)

    Siltala, Lauri; Granvik, Mikael

    2016-10-01

    Estimates for asteroid masses are based on their gravitational perturbations on the orbits of other objects such as Mars, spacecraft, or other asteroids and/or their satellites. In the case of asteroid-asteroid perturbations, this leads to a 13-dimensional inverse problem where the aim is to derive the mass of the perturbing asteroid and six orbital elements for both the perturbing asteroid and the test asteroid using astrometric observations. We have developed and implemented three different mass estimation algorithms utilizing asteroid-asteroid perturbations into the OpenOrb asteroid-orbit-computation software: the very rough 'marching' approximation, in which the asteroid orbits are fixed at a given epoch, reducing the problem to a one-dimensional estimation of the mass, an implementation of the Nelder-Mead simplex method, and most significantly, a Markov-Chain Monte Carlo (MCMC) approach. We will introduce each of these algorithms with particular focus on the MCMC algorithm, and present example results for both synthetic and real data. Our results agree with the published mass estimates, but suggest that the published uncertainties may be misleading as a consequence of using linearized mass-estimation methods. Finally, we discuss remaining challenges with the algorithms as well as future plans, particularly in connection with ESA's Gaia mission.

  20. Seven Near-Earth Asteroids at Asteroids Observers (OBAS) - MPPD: 2016 June-November

    Science.gov (United States)

    Lozano, Juan; Flores, Angel; Mas, Vicente; Fornas, Gonzalo; Rodrigo, Onofre; Brines, Pedro; Forna, Alvaro; Herrero, David; Carreño, Alfonso; Arce, Enrique

    2017-04-01

    We report on the results of photometric analysis on seven near-Earth asteroids (NEA) by Asteroides Observers (OBAS). This work is part of the Minor Planet Photometric Database effort that was initiated by a group of Spanish amateur astronomers. We have managed to obtain a number of accurate and complete lightcurves as well as some additional incomplete lightcurves to help analysis at future oppositions.

  1. Twenty-one Asteroid Lightcurves at Group Observadores de Asteroides (OBAS): Late 2015 to Early 2016

    Science.gov (United States)

    Aznar Macias, Amadeo; Carreno Garcerain, Alfonso; Arce Masego, Enrique; Brines Rodriguez, Pedro; Lozano de Haro, Juan; Fornas Silva, Alvaro; Fornas Silva, Gonzalo; Mas Martinez, Vicente; Rodrigo Chiner, Onofre; Herrero Porta, David

    2016-07-01

    We report on the photometric analysis result of 21 mainbelt asteroids (MBA) done by Observadores de Asteroides (OBAS). This work is part of the Minor Planet Photometric Database task initiated by a group of Spanish amateur astronomers. We have managed to obtain a number of accurate and complete lightcurves as well as additional incomplete lightcurves to help analysis at future oppositions. This is a compilation of lightcurves obtained during last quarter of 2015 and first quarter of 2016.

  2. Hungaria Asteroid Region Telescopic Spectral Survey (HARTSS): Stony Asteroids Abundant in the Background and Family Populations

    Science.gov (United States)

    Lucas, Michael P.; Emery, Joshua P.; Pinilla-Alonso, Noemi; Lindsay, Sean S.; Lorenzi, Vania

    2016-10-01

    The Hungaria region represents a "purgatory" for the closest, preserved samples of the material from which the terrestrial planets accreted. The Hungaria region harbors a collisional family of Xe-type asteroids, which are situated among a background of predominantly S-complex asteroids. Deciphering their surface composition may provide constraints on the nature of the primordial building blocks of the terrestrial planets. We hypothesize that planetesimals in the inner part of the primordial asteroid belt experienced partial- to full-melting and differentiation, the Hungaria region should retain any petrologically-evolved material that formed there.We have undertaken an observational campaign entitled the Hungaria Asteroid Region Telescopic Spectral Survey (HARTSS) to record near-infrared (NIR) spectra to characterize taxonomy, surface mineralogy, and potential meteorite analogs. We used NIR instruments at two ground-based facilities (NASA IRTF; TNG). Our data set includes spectra of 82 Hungaria asteroids (61 background; 21 family), 65 were observed during HARTSS. We compare S-complex background asteroids to calibrations developed via laboratory analyses of ordinary chondrites, and to our analyses (EPMA, XRD, VIS+NIR spectra) of 11 primitive achondrite (acapulcoite-lodranite clan) meteorites.We find that stony S-complex asteroids dominate the Hungaria background population (~80%). Background objects exhibit considerable spectral diversity, when quantified by spectral band parameter measurements, translates to a variety of surface compositions. Two main meteorite groups are represented within the Hungaria background: unmelted, nebular L chondrites (and/or L chondrites), and partially-melted primitive achondrites. H-chondrite mineralogies appear to be absent from the Hungaria background. Xe-type Hungaria family members exhibit spectral homogeneity, consistent with the hypothesis that the family was derived from the disruption of a parent body analogous to an enstatite

  3. Asteroid modeling for testing spacecraft approach and landing.

    Science.gov (United States)

    Martin, Iain; Parkes, Steve; Dunstan, Martin; Rowell, Nick

    2014-01-01

    Spacecraft exploration of asteroids presents autonomous-navigation challenges that can be aided by virtual models to test and develop guidance and hazard-avoidance systems. Researchers have extended and applied graphics techniques to create high-resolution asteroid models to simulate cameras and other spacecraft sensors approaching and descending toward asteroids. A scalable model structure with evenly spaced vertices simplifies terrain modeling, avoids distortion at the poles, and enables triangle-strip definition for efficient rendering. To create the base asteroid models, this approach uses two-phase Poisson faulting and Perlin noise. It creates realistic asteroid surfaces by adding both crater models adapted from lunar terrain simulation and multiresolution boulders. The researchers evaluated the virtual asteroids by comparing them with real asteroid images, examining the slope distributions, and applying a surface-relative feature-tracking algorithm to the models.

  4. NASA hits back in asteroid spat

    Science.gov (United States)

    Cartlidge, Edwin

    2016-07-01

    Nathan Myhrvold, chief executive of the company Intellectual Ventures and a former chief technology officer of Microsoft, is at loggerheads with a group of NASA astrophysicists over the latter's ability to accurately measure the properties of tens of thousands of asteroids in the solar system.

  5. A note on cement in asteroids

    Science.gov (United States)

    Bilalbegović, G.

    2016-09-01

    Cement mineral tobermorite was formed in hydrothermal experiments on alternation of calcium-aluminum-rich inclusions (CAIs) in carbonaceous chondrite meteorites. Unidentified bands at 14 μm were measured for CAIs and the matrix of the Allende meteorite sample, as well as for Hektor and Agamemnon asteroids. The presence of cement nanoparticles may explain the feature at 14 μm.

  6. Spectroscopic Survey of X-type Asteroids

    CERN Document Server

    Fornasier, Sonia; Dotto, Elisabetta

    2011-01-01

    We present reflected light spectral observations from 0.4 to 2.5 micron of 24 asteroids chosen from the population of asteroids initially classified as Tholen X-type objects (Tholen, 1984). The X complex in the Tholen taxonomy comprises the E, M and P classes which have very different inferred mineralogies but which are spectrally similar to each other, with featureless spectra in visible wavelengths. The data were obtained during several observing runs in the 2004-2007 years at the NTT, TNG and IRTF telescopes. We find a large variety of near-infrared spectral behaviors within the X class, and we identify weak absorption bands in spectra of 11 asteroids. Our spectra, together with albedos published by Tedesco et al. (2002), can be used to suggest new Tholen classifications for these objects. In order to constrain the possible composition of these asteroids, we perform a least-squares search through the RELAB spectral database. Many of the best fits are consistent with meteorite analogue materials suggested i...

  7. Asteroid Risk Assessment: A Probabilistic Approach.

    Science.gov (United States)

    Reinhardt, Jason C; Chen, Xi; Liu, Wenhao; Manchev, Petar; Paté-Cornell, M Elisabeth

    2016-02-01

    Following the 2013 Chelyabinsk event, the risks posed by asteroids attracted renewed interest, from both the scientific and policy-making communities. It reminded the world that impacts from near-Earth objects (NEOs), while rare, have the potential to cause great damage to cities and populations. Point estimates of the risk (such as mean numbers of casualties) have been proposed, but because of the low-probability, high-consequence nature of asteroid impacts, these averages provide limited actionable information. While more work is needed to further refine its input distributions (e.g., NEO diameters), the probabilistic model presented in this article allows a more complete evaluation of the risk of NEO impacts because the results are distributions that cover the range of potential casualties. This model is based on a modularized simulation that uses probabilistic inputs to estimate probabilistic risk metrics, including those of rare asteroid impacts. Illustrative results of this analysis are presented for a period of 100 years. As part of this demonstration, we assess the effectiveness of civil defense measures in mitigating the risk of human casualties. We find that they are likely to be beneficial but not a panacea. We also compute the probability-but not the consequences-of an impact with global effects ("cataclysm"). We conclude that there is a continued need for NEO observation, and for analyses of the feasibility and risk-reduction effectiveness of space missions designed to deflect or destroy asteroids that threaten the Earth.

  8. Asteroid thermal modeling: recent developments and applications

    NARCIS (Netherlands)

    Harris, A. W.; Mueller, M.

    2006-01-01

    A variety of thermal models are used for the derivation of asteroid physical parameters from thermal-infrared observations Simple models based on spherical geometry are often adequate for obtaining sizes and albedos when very little information about an object is available However sophisticated ther

  9. Spectroscopic survey of M--type asteroids

    CERN Document Server

    Fornasier, S; Dotto, E; Migliorini, A; Ockert-Bell, M; Barucci, M A

    2010-01-01

    M-type asteroids, as defined in the Tholen taxonomy (Tholen, 1984), are medium albedo bodies supposed to have a metallic composition and to be the progenitors both of differentiated iron-nickel meteorites and enstatite chondrites. We carried out a spectroscopic survey in the visible and near infrared wavelength range (0.4-2.5 micron) of 30 asteroids chosen from the population of asteroids initially classified as Tholen M -types, aiming to investigate their surface composition. The data were obtained during several observing runs during the years 2004-2007 at the TNG, NTT, and IRTF telescopes. We computed the spectral slopes in several wavelength ranges for each observed asteroid, and we searched for diagnostic spectral features. We confirm a large variety of spectral behaviors for these objects as their spectra are extended into the near-infrared, including the identification of weak absorption bands, mainly of the 0.9 micron band tentatively attributed to orthopyroxene, and of the 0.43 micron band that may b...

  10. A note on cement in asteroids

    CERN Document Server

    Bilalbegovic, G

    2016-01-01

    Cement mineral tobermorite was formed in hydrothermal experiments on alternation of calcium-aluminum-rich inclusions (CAIs) in carbonaceous chondrite meteorites. Unidentified bands at 14 microns were measured for CAIs and the matrix of the Allende meteorite sample, as well as for Hektor and Agamemnon asteroids. The presence of cement nanoparticles may explain the feature at 14 microns.

  11. Collisional Excavation of Asteroid (596) Scheila

    CERN Document Server

    Bodewits, D; Li, J -Y; Landsman, W B; Besse, S; A'Hearn, M F

    2011-01-01

    We observed asteroid (596) Scheila and its ejecta cloud using the Swift UV-optical telescope. We obtained photometry of the nucleus and the ejecta, and for the first time measured the asteroid's reflection spectrum between 290 - 500 nm. Our measurements indicate significant reddening at UV wavelengths (13% per 1000 {\\AA}) and a possible broad, unidentified absorption feature around 380 nm. Our measurements indicate that the outburst has not permanently increased the asteroid's brightness. We did not detect any of the gases that are typically associated with either hypervolatile activity thought responsible for cometary outbursts (CO+, CO2+), or for any volatiles excavated with the dust (OH, NH, CN, C2, C3). We estimate that 6 x 10^8 kg of dust was released with a high ejection velocity of 57 m/s (assuming 1 {\\mu}m sized particles). While the asteroid is red in color and the ejecta have the same color as the Sun, we suggest that the dust does not contain any ice. Based on our observations, we conclude that (59...

  12. Rotation Properties of Small Jovian Trojan Asteroids

    Science.gov (United States)

    French, Linda M.; Stephens, Robert D.; James, David; Coley, Daniel R.; Warner, Brian D.; Rohl, Derrick

    2016-10-01

    Jovian Trojan asteroids are of interest both as objects in their own right (we have no spectral analogs among meteorite samples) and as possible relics of Solar System formation. Asteroid lightcurves can give information about processes that have affected a group of asteroids; they can also give information about the density of the objects when enough lightcurves have been collected. We have been carrying out a survey of Trojan lightcurve properties for comparison with small asteroids and with comets. In a recent paper (French et al. 2015) we presented evidence that a significant number of Trojans have rotation periods greater than 24 hours. We will report our latest results and compare them with results of sparsely-sampled lightcurves from the Palomar Transient Factory (Waszczak et al. 2015). LF, RS, and DR were visiting astronomers at Cerro Tololo Interamerican Observatory, operated by AURA under contract with the NSF, and with the SMARTS Consortium at CTIO. This research was sponsored by NSF Planetary Astronomy grant 1212115.ReferencesFrench, L.M. et al. 2015. Icarus 254, pp. 1-17.Waszczak, A. et al. 2015. A.J. 150, Issue 3, I.D. 35.

  13. Comet nucleus and asteroid sample return missions

    Science.gov (United States)

    1992-01-01

    Three Advanced Design Projects have been completed this academic year at Penn State. At the beginning of the fall semester the students were organized into eight groups and given their choice of either a comet nucleus or an asteroid sample return mission. Once a mission had been chosen, the students developed conceptual designs. These were evaluated at the end of the fall semester and combined into three separate mission plans, including a comet nucleus same return (CNSR), a single asteroid sample return (SASR), and a multiple asteroid sample return (MASR). To facilitate the work required for each mission, the class was reorganized in the spring semester by combining groups to form three mission teams. An integration team consisting of two members from each group was formed for each mission so that communication and information exchange would be easier among the groups. The types of projects designed by the students evolved from numerous discussions with Penn State faculty and mission planners at the Johnson Space Center Human/Robotic Spacecraft Office. Robotic sample return missions are widely considered valuable precursors to manned missions in that they can provide details about a site's environment and scientific value. For example, a sample return from an asteroid might reveal valuable resources that, once mined, could be utilized for propulsion. These missions are also more adaptable when considering the risk to humans visiting unknown and potentially dangerous locations, such as a comet nucleus.

  14. Asteroid models from the Lowell Photometric Database

    CERN Document Server

    Durech, J; Oszkiewicz, D; Vanco, R

    2016-01-01

    We use the lightcurve inversion method to derive new shape models and spin states of asteroids from the sparse-in-time photometry compiled in the Lowell Photometric Database. To speed up the time-consuming process of scanning the period parameter space through the use of convex shape models, we use the distributed computing project Asteroids@home, running on the Berkeley Open Infrastructure for Network Computing (BOINC) platform. This way, the period-search interval is divided into hundreds of smaller intervals. These intervals are scanned separately by different volunteers and then joined together. We also use an alternative, faster, approach when searching the best-fit period by using a model of triaxial ellipsoid. By this, we can independently confirm periods found with convex models and also find rotation periods for some of those asteroids for which the convex-model approach gives too many solutions. From the analysis of Lowell photometric data of the first 100,000 numbered asteroids, we derived 328 new ...

  15. Asteroids Lightcurves Analysis: 2015 October-December

    Science.gov (United States)

    Carbognani, Albino; Buzzi, Luca

    2016-04-01

    Eight asteroids, main-belt (MBA) and near-Earth (NEA), were observed in 2015 Oct-Dec: 6853 Silvanomassaglia, (112985) 2002 RS28, (155110) 2005 TB, (163899) 2003 SD220, (253106) 2002 UR3, (337866) 2001 WL15, 2015 XC, and 2015 WG9.

  16. Early formation of evolved asteroidal crust.

    Science.gov (United States)

    Day, James M D; Ash, Richard D; Liu, Yang; Bellucci, Jeremy J; Rumble, Douglas; McDonough, William F; Walker, Richard J; Taylor, Lawrence A

    2009-01-08

    Mechanisms for the formation of crust on planetary bodies remain poorly understood. It is generally accepted that Earth's andesitic continental crust is the product of plate tectonics, whereas the Moon acquired its feldspar-rich crust by way of plagioclase flotation in a magma ocean. Basaltic meteorites provide evidence that, like the terrestrial planets, some asteroids generated crust and underwent large-scale differentiation processes. Until now, however, no evolved felsic asteroidal crust has been sampled or observed. Here we report age and compositional data for the newly discovered, paired and differentiated meteorites Graves Nunatak (GRA) 06128 and GRA 06129. These meteorites are feldspar-rich, with andesite bulk compositions. Their age of 4.52 +/- 0.06 Gyr demonstrates formation early in Solar System history. The isotopic and elemental compositions, degree of metamorphic re-equilibration and sulphide-rich nature of the meteorites are most consistent with an origin as partial melts from a volatile-rich, oxidized asteroid. GRA 06128 and 06129 are the result of a newly recognized style of evolved crust formation, bearing witness to incomplete differentiation of their parent asteroid and to previously unrecognized diversity of early-formed materials in the Solar System.

  17. Massive identification of asteroids in three-body resonances

    Science.gov (United States)

    Smirnov, Evgeny A.; Shevchenko, Ivan I.

    2013-01-01

    An essential role in the asteroidal dynamics is played by the mean motion resonances. Two-body planet-asteroid resonances are widely known, due to the Kirkwood gaps. Besides, so-called three-body mean motion resonances exist, in which an asteroid and two planets participate. Identification of asteroids in three-body (namely, Jupiter-Saturn-asteroid) resonances was initially accomplished by Nesvorný and Morbidelli (Nesvorný D., Morbidelli, A. [1998]. Astron. J. 116, 3029-3037), who, by means of visual analysis of the time behaviour of resonant arguments, found 255 asteroids to reside in such resonances. We develop specialized algorithms and software for massive automatic identification of asteroids in the three-body, as well as two-body, resonances of arbitrary order, by means of automatic analysis of the time behaviour of resonant arguments. In the computation of orbits, all essential perturbations are taken into account. We integrate the asteroidal orbits on the time interval of 100,000 yr and identify main-belt asteroids in the three-body Jupiter-Saturn-asteroid resonances up to the 6th order inclusive, and in the two-body Jupiter-asteroid resonances up to the 9th order inclusive, in the set of ˜250,000 objects from the "Asteroids - Dynamic Site" (AstDyS) database. The percentages of resonant objects, including extrapolations for higher-order resonances, are determined. In particular, the observed fraction of pure-resonant asteroids (those exhibiting resonant libration on the whole interval of integration) in the three-body resonances up to the 6th order inclusive is ≈0.9% of the whole set; and, using a higher-order extrapolation, the actual total fraction of pure-resonant asteroids in the three-body resonances of all orders is estimated as ≈1.1% of the whole set.

  18. 3-µm Spectroscopy of Asteroid 16 Psyche

    Science.gov (United States)

    Takir, Driss; Reddy, Vishnu; Sanchez, Juan; Shepard, Michael K.

    2016-10-01

    Asteroid 16 Psyche, an M-type asteroid, is thought to be one of the most massive exposed iron metal object in the asteroid belt. The high radar albedos of Psyche suggest that this differentiated asteroid is dominantly composed of metal. Psyche was previously found to be featureless in the 3-µm spectral region. However, in our study we found that this asteroid exhibits a 3-µm absorption feature, possibly indicating the presence of hydrated silicates.We have observed Psyche in the 3-µm spectral region, using the long-wavelength cross-dispersed (LXD:1.9-4.2 µm) mode of the SpeX spectrograph/imager at the NASA Infrared Telescope Facility (IRTF). For data reduction, we used the IDL (Interactive Data Language)-based spectral reduction tool Spextool (v4.1). Psyche was observed over the course of three nights with an apparent visual magnitude of ~9.50: 8 December 2015 (3 sets), 9 December 2015 (1 set), and 10 March 2016 (1 set). These observations have revealed that Psyche may exhibit a 3-µm absorption feature, similar to the sharp group in the 2.9-3.3-µm spectral range. Psyche also exhibits an absorption feature similar to the one in Ceres and Ceres-like group in the spectral 3.3-4.0-µm range. These 3-µm observational results revealed that Psyche may not be as featureless as once thought in the 3-µm spectral region.Evidence for the 3-µm band was found on the surfaces of many M-type asteroids and a number of plausible alternative interpretations for the presence of this 3-µm band were previously suggested. These interpretations include the presence of anhydrous silicates containing structural OH, the presence of fluid inclusions, the presence of xenolithic hydrous meteorite components on asteroid surfaces from impacts, solar wind-implanted H, or the presence of troilite. The detection of the Ceres-like feature in the 3.3-4.0-µm spectral range, however, would rule out some of these alternative interpretations, especially the solar wind-implanted H.

  19. The partial fission of fast spinning asteroids

    Science.gov (United States)

    Tardivel, Simon; Sanchez, Paul; Scheeres, Daniel J.

    2016-10-01

    The spin rates of asteroids systematically change over time due the Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) effect. Above a certain spin rate that depends on the body's density, regions of an asteroid can enter in tension, with components held to the body by cohesive forces. When the body fails, deformation or fission can occur. Catastrophic fission leading to complete disruption has been directly observed in active asteroid P/2013 R3. Partial fission, the loss of only part of the body, has been proposed as a mechanism for the formation of binaries and is explored here.The equatorial cavities of (341843) 2008 EV5 and of (185851) 2000 DP107 (a binary system) are consistent with a localized partial fission of the body (LPSC 2016 #1036). The examination of the gravity field of these bodies reveals that a mass placed within these cavities could be shed. In this mechanism, the outward pull of inertial forces creates an average stress at the cavity interface of ≈1 Pa for 2008 EV5 and ≈3 Pa for 2000 DP107 at spin periods of ≈3.15 h for the assumed densities of 1.3 g/cm3.This work continues the study of this partial, localized fission. Specifically, it addresses the issue of the low cohesion necessary to the mechanism. These cohesion values are typically lower than global strength values inferred on other asteroids (10 - 200 Pa), meaning that partial fission may occur prior to larger-scale deformations. Yet, several processes can explain the discrepancy, as they can naturally segregate particles by size. For instance, landslides or granular convection (Brazil nut effect) could bring larger boulders to the equator of the body, while finer particles are left at higher latitudes or sink to the center. Conversely, failure of the interior could bring boulders to the surface. The peculiar profile shape of these asteroids, shared by many binaries (e.g. 1999 KW4, 1996 FG3) may also be a clue of this heterogeneity, as this "spin top" shape is obtained in simulations with

  20. Reducing the Asteroid and Comet Impact Hazard

    Science.gov (United States)

    Crawford, David

    1998-10-01

    Of the 140 impact craters known on the surface of Earth, the most famous was created about 65 million years ago when a 10 km asteroid or comet came down in shallow water near the present day town of Chicxulub, Mexico. With a kinetic energy equivalent to 100 trillion tons of TNT, the impact event lofted enough debris onto globe-straddling trajectories to flash heat much of the surface of the Earth and then darken the skies for several years. Numerous investigations have demonstrated that such an event, which happens, on average, every 100 million years, caused extreme stress on Earth's climate and most likely led to the extinction of many species. Computational simulations demonstrate that more numerous asteroids or comets as small as 1 km in diameter, impacting, on average, every 300,000 years may be globally catastrophic. Indeed, the odds of an individual dying from a relatively frequent 1 km impacting object (about 1 in 10,000) are substantially greater than from the impact of an infrequent dinosaur killer (1 in 1,000,000). What can we do to reduce the hazard from impacting comets and asteroids? First, we should find what's out there with our name on it. Only about 10 percent of the potential Earth-crossing asteroids have been found. Even at the greatly increased detection rate of recent years, it will be several decades before we've found 90 percent of the Earth-crossers. Second, we should learn everything we can about the physical, compositional and mechanical properties of asteroids and comets. A recent computational study demonstrated that weakly bound asteroids (little more than rubble piles) are easier to break than deflect(E. Asphaug, S. J. Ostro, R. S. Hudson, D. J. Scheeres and W. Benz (1998), Nature, Vol. 393, pp. 437-440.). Is this an advantage or disadvantage? Third, we should study potential means of mitigating the hazard by deflecting the object while still in space or evacuating affected regions (such as coastlines) of the Earth. Because the

  1. The Advanced Jovian Asteroid Explorer (AJAX)

    Science.gov (United States)

    Murchie, S. L.; Adams, E. Y.; Mustard, J. F.; Rivkin, A.; Peplowski, P. N.

    2015-12-01

    The Advanced Jovian Asteroid eXplorer (AJAX) is the first mission to characterize the geology, morphology, geophysical properties, and chemistry of a Trojan asteroid. The Decadal Survey outlined a notional New Frontiers class Trojan asteroid rendezvous mission to conduct geological, elemental composition, mineralogical, and geophysical investigations. AJAX, our Discovery mission proposal, addresses the Decadal Survey science goals by using a focused payload and an innovative mission design. By responding to the most important questions about the Trojan asteroids, AJAX advances our understanding of all of the Solar System. Are these objects a remnant population of the local primordial material from which the outer planets and their satellites formed, or did they originate in the Kuiper Belt? Landed measurements of major and minor elements test hypotheses for the Trojan asteroid origin, revealing the outer Solar System dynamical history. How and when were prebiotic materials delivered to the terrestrial planets? AJAX's landed measurements include C and H concentrations, necessary to determine their inventories of volatiles and organic compounds, material delivered to the inner Solar System during the Late Heavy Bombardment. What chemical and geological processes shaped the small bodies that merged to form the planets in our Solar System? AJAX investigates the asteroid internal structure, geology, and regolith by using global high-resolution stereo and multispectral imaging, determining density and estimating interior porosity by measuring gravity, and measuring regolith mechanical properties by landing. AJAX's science phase starts with search for natural satellites and dust lifted by possible cometary activity and shape and pole position determination. AJAX descends to lower altitudes for global mapping, and conducts a low flyover for high-resolution surface characterization and measurement of hydrogen abundance. Finally, it deploys a small landed package, which

  2. OSIRIS-REx, Returning the Asteroid Sample

    Science.gov (United States)

    Ajluni, Thomas, M.; Everett, David F.; Linn, Timothy; Mink, Ronald; Willcockson, William; Wood, Joshua

    2015-01-01

    This paper addresses the technical aspects of the sample return system for the upcoming Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer (OSIRIS-REx) asteroid sample return mission. The overall mission design and current implementation are presented as an overview to establish a context for the technical description of the reentry and landing segment of the mission.The prime objective of the OSIRIS-REx mission is to sample a primitive, carbonaceous asteroid and to return that sample to Earth in pristine condition for detailed laboratory analysis. Targeting the near-Earth asteroid Bennu, the mission launches in September 2016 with an Earth reentry date of September 24, 2023.OSIRIS-REx will thoroughly characterize asteroid Bennu providing knowledge of the nature of near-Earth asteroids that is fundamental to understanding planet formation and the origin of life. The return to Earth of pristine samples with known geologic context will enable precise analyses that cannot be duplicated by spacecraft-based instruments, revolutionizing our understanding of the early Solar System. Bennu is both the most accessible carbonaceous asteroid and one of the most potentially Earth-hazardous asteroids known. Study of Bennu addresses multiple NASA objectives to understand the origin of the Solar System and the origin of life and will provide a greater understanding of both the hazards and resources in near-Earth space, serving as a precursor to future human missions to asteroids.This paper focuses on the technical aspects of the Sample Return Capsule (SRC) design and concept of operations, including trajectory design and reentry retrieval. Highlights of the mission are included below.The OSIRIS-REx spacecraft provides the essential functions for an asteroid characterization and sample return mission: attitude control propulsion power thermal control telecommunications command and data handling structural support to ensure successful

  3. Geologic History of Asteroid 4 Vesta

    Science.gov (United States)

    Mittlefehldt, David W.

    2014-01-01

    Some types of meteorites - most irons, stony irons, some achondrites - hail from asteroids that were heated to the point where magmatism occurred within a very few million years of the formation of the earliest solids in the solar system. The largest clan of achondrites, the howardite, eucrite and diogenite (HED) meteorites, represent the crust of their parent asteroid]. Diogenites are cumulate harzburgites and orthopyroxenites from the lower crust whilst eucrites are basalts, diabases and cumulate gabbros from the upper crust. Howardites are impact-engendered breccias mostly of diogenites and eucrites. There remains only one large asteroid with a basaltic crust, 4 Vesta, which is thought to be the source of the HED clan. Differentiation models for Vesta are based on HED compositions. Proto-Vesta consisted of chondritic materials containing Al-26, a potent, short-lived heat source. Inferences from compositional data are that Vesta was melted to high degree (=50%) allowing homogenization of the silicate phase and separation of a metallic core. Convection of the silicate magma ocean allowed equilibrium crystallization, forming a harzburgitic mantle. After convective lockup occurred, melt collected between the mantle and the cool thermal boundary layer and underwent fractional crystallization forming an orthopyroxene-rich (diogenite) lower crust. The initial thermal boundary layer of chondritic material was replaced by a mafic upper crust through impact disruption and foundering. The mafic crust thickened over time as additional residual magma intrudes and penetrates the mafic crust forming plutons, dikes, sills and flows of cumulate and basaltic eucrite composition. This magmatic history may have taken only 2-3 Myr. This magma ocean scenario is at odds with a model of heat and magma transport that indicates that small degrees of melt would be rapidly expelled from source regions, precluding development of a magma ocean. Constraints from radiogenic Mg-26 distibutions

  4. PRIMitive Asteroids Spectroscopic Survey - PRIMASS: First Results

    Science.gov (United States)

    de Leon, Julia; Pinilla-Alonso, Noemi; Campins, Humberto; Lorenzi, Vania; Licandro, Javier; Morate, David; Tanga, Paolo; Cellino, Alberto; Delbo, Marco

    2015-11-01

    NASA OSIRIS-REx and JAXA Hayabusa 2 sample-return missions have targeted two near-Earth asteroids: (101955) Bennu and (162173) 1999 JU3, respectively. These are primitive asteroids that are believed to originate in the inner belt, where five distinct sources have been identified: four primitive collisional families (Polana, Erigone, Sulamitis, and Clarissa), and a population of low-albedo and low-inclination background asteroids. Identifying and characterizing the populations from which these two NEAs might originate will enchance the science return of the two missions.With this main objective in mind, we initiated in 2010 a spectroscopic survey in the visible and the near-infrared to characterize the primitive collisional families in the inner belt and the low-albedo background population. This is the PRIMitive Asteroids Spectroscopic Survey - PRIMASS. So far we have obtained more than 200 spectra using telescopes located at different observatories. PRIMASS uses a variety of ground based facilities. Most of the spectra have been obtained using the 10.4m Gran Telescopio Canarias (GTC), and the 3.6m Telescopio Nazionale Galileo (TNG), both located at the El Roque de los Muchachos Observatory (La Palma, Spain), and the 3.0m NASA Infrared Telescope Facility on Mauna Kea (Hawai, USA).We present the first results from our on-going survey (de Leon et al. 2015; Pinilla-Alonso et al. 2015; Morate et al. 2015), focused on the Polana and the Erigone primitive families, with visible and near-infrared spectra of more than 200 objects, most of them with no previous spectroscopic data. Our survey is already the largest database of primitive asteroids spectra, and we keep obtaining data on the Sulamitis and the Clarissa families, as well as on the background low-albedo population.

  5. Regolith Levitation on Small Fast Rotating Asteroids

    Science.gov (United States)

    Campo Bagatin, Adriano; Moreno, Fernando; Molina, Antonio

    2014-11-01

    A number of NEAs larger than few hundred meters are found with relatively high spin rates (from ~2.2 to less than 4 hr, depending on composition). On those bodies, local acceleration near their equator may be directed outwards, as in the case of the primaries of binary asteroids Didymos and 1996 FG3. They both are potential targets of future space missions. What are the effects of high spin states on regolith material at low asteroidal latitudes?NEAs come from the asteroid belt and are believed to be mostly gravitational aggregates at D > 0.5 - 1 km due to their former collisional evolution history (Campo Bagatin et al, 2001). Once in the inner Solar System, NEAs may undergo spin up evolution through YORP causing their components to disperse, shed mass or fission and eventually form binary, multiple systems or asteroid pairs (Walsh et al, 2008, Jacobson and Scheers, 2010, Pravec et al, 2009 and 2010). The end state of those events is often an object spinning above any Chandrasekhar stability limit, kept together by friction (Holsapple, 2007) and sometimes characterized by an equatorial “bulge”, as shown by radar images (Ostro et al, 2006).The centrifugal force acting on surface particles at equatorial latitudes may overcome the gravitational pull of the asteroid itself, and particles may leave its suface. Centrifugal is an apparent contact force, and as soon as particles lift off they mainly move under the gravitational field of the asteroid and the satellite, they may levitate for some time, land on the surface and repeat this cycle over and over. We are studying the motion of particles in the 1 μm to 10 cm range in the non-inertial reference frame of the rotating primary, accounting for centrifugal and Coriolis apparent forces as well as the gravitational fields of the primary, the secondary, the Sun and the radiation forces by the Sun itself. The main features of this effect are presented in the case of Didymos and 1996 FG3.

  6. Reverse Asteroids: Searching for an Effective Tool to Combat Asteroid Belt Misconceptions

    Science.gov (United States)

    Summers, F.; Eisenhamer, B.

    2014-12-01

    The public 'knows' that asteroid belts are densely packed and dangerous for spaceships to cross. Visuals from "Star Wars" to, unfortunately, the recent "Cosmos" TV series have firmly established this astronomical misconception. However, even scientifically correct graphics, such as the Minor Planet Center's plot of the inner solar system, reinforces that view. Each pixel in the image is more than a million kilometers in width, making an accurate representation of the object density impossible.To address this widespread misconception, we are investigating an educational exercise built around a computer interactive that we call "Reverse Asteroids". In the arcade classic video game, the asteroids came to the player's spaceship. For our reverse implementation, we consider an inquiry-based activity in which the spaceship must go hunting for the asteroids, using a database of real objects in our solar system. Both 3D data visualization and basic statistical analysis play crucial roles in bringing out the true space density within the asteroid belt, and perhaps a reconciliation between imagination and reality. We also emphasize that a partnership of scientists and educators is fundamental to the success of such projects.

  7. Asteroid Deflection Using a Spacecraft in Restricted Keplerian Motion

    CERN Document Server

    Ketema, Yohannes

    2016-01-01

    A method for asteroid deflection that makes use of a spacecraft moving back and forth on a segment of an appropriate Keplerian orbit about the asteroid is described and evaluated. It is shown that, on average, the spacecraft describing such a trajectory can exert a significantly larger force on the asteroid than e.g. a stationary gravity tractor, thereby reducing the time needed to effect a desired velocity change for the asteroid. Furthermore, the current method does not require canted thrusters on the spacecraft (unlike a stationary gravity tractor), markedly reducing the amount of fuel needed to create a given change in the asteroid velocity. In addition, the method allows for the simultaneous use of several spacecraft, further strengthening the overall tugging effect on the asteroid, and distributing the thrust requirement among the spacecraft.

  8. Chang'e-2 spacecraft observations of asteroid 4179 Toutatis

    CERN Document Server

    Ji, Jianghui; Zhao, Yuhui; Wang, Su; Yu, Liangliang

    2015-01-01

    On 13 December 2012, Chang'e-2 completed a successful flyby of the near-Earth asteroid 4179 Toutatis at a closest distance of 770 meters from the asteroid's surface. The observations show that Toutatis has an irregular surface and its shape resembles a ginger-root of a smaller lobe (head) and a larger lobe (body). Such bilobate shape is indicative of a contact binary origin for Toutatis. In addition, the high-resolution images better than 3 meters provide a number of new discoveries about this asteroid, such as an 800-meter depression at the end of the large lobe, a sharply perpendicular silhouette near the neck region, boulders, indicating that Toutatis is probably a rubble-pile asteroid. Chang'e-2 observations have significantly revealed new insights into the geological features and the formation and evolution of this asteroid. In final, we brief the future Chinese asteroid mission concept.

  9. Radar observations of the asteroid 2011 UW158

    Science.gov (United States)

    Ipatov, A. V.; Bondarenko, Yu. S.; Medvedev, Yu. D.; Mishina, N. A.; Marshalov, D. A.; Benner, L. A.

    2016-12-01

    In July 2015 intercontinental bistatic radar observations of the potentially dangerous asteroid 2011 UW158 during its close approach to the Earth were carried out. The asteroid was illuminated at a frequency of 8.4 GHz with the 70-m DSS-14 antenna of the Goldstone Deep Space Communications Complex, while the signal reflected from the asteroid was received with the 32-m radio telescopes of the Quasar VLBI network at the Zelenchukskaya and Badary Observatories. The spectra of the reflected radio signals were obtained. The sizes and rotation period of the asteroid consistent with photometric observations and the ratio of the powers of the reflected signals with left- and right-hand circular polarizations were determined. The derived values suggest that the asteroid has an inhomogeneous surface and a prolate shape. The observations of the Doppler shift of the reflected signal frequency were obtained, which allowed the orbital parameters of the asteroid to be improved.

  10. Chang'e-2 spacecraft observations of asteroid 4179 Toutatis

    Science.gov (United States)

    Ji, Jianghui; Jiang, Yun; Zhao, Yuhui; Wang, Su; Yu, Liangliang

    2016-01-01

    On 13 December 2012, Chang'e-2 completed a successful flyby of the near-Earth asteroid 4179 Toutatis at a closest distance of 770 meters from the asteroid's surface. The observations show that Toutatis has an irregular surface and its shape resembles a ginger-root of a smaller lobe (head) and a larger lobe (body). Such bilobate shape is indicative of a contact binary origin for Toutatis. In addition, the high-resolution images better than 3 meters provide a number of new discoveries about this asteroid, such as an 800-meter depression at the end of the large lobe, a sharply perpendicular silhouette near the neck region, boulders, indicating that Toutatis is probably a rubble-pile asteroid. Chang'e-2 observations have significantly revealed new insights into the geological features and the formation and evolution of this asteroid. In final, we brief the future Chinese asteroid mission concept.

  11. Equilibrium figures of inhomogeneous synchronous binary asteroids

    Science.gov (United States)

    Descamps, P.

    2010-06-01

    The present paper deals with the application of the classical theory of equilibrium figures of two rotating liquid masses to the case where bodies exhibit a radially stratified internal density distribution so that they can be considered as inhomogeneous bodies. The derived ellipsoidal shape solutions are applied to five real systems of equal-sized synchronous asteroids. Furthermore, internal inhomogeneity puts strong constraints on the surface grain density. A satisfactory model fit is achieved with internal densities of asteroids steadily increasing outwards. In particular, from such an approach we derived grain densities of the considered systems in agreement with their mineralogical composition inferred from reflectance spectroscopy. According to this new approach, 4492 Debussy, presently of unknown spectral type, is predicted to appear as a C-type object with a grain density on the order of 2 g/cm 3.

  12. Asteroid absolute magnitudes and slope parameters

    Science.gov (United States)

    Tedesco, Edward F.

    1991-01-01

    A new listing of absolute magnitudes (H) and slope parameters (G) has been created and published in the Minor Planet Circulars; this same listing will appear in the 1992 Ephemerides of Minor Planets. Unlike previous listings, the values of the current list were derived from fits of data at the V band. All observations were reduced in the same fashion using, where appropriate, a single basis default value of 0.15 for the slope parameter. Distances and phase angles were computed for each observation. The data for 113 asteroids was of sufficiently high quality to permit derivation of their H and G. These improved absolute magnitudes and slope parameters will be used to deduce the most reliable bias-corrected asteroid size-frequency distribution yet made.

  13. Effective stability of the Trojan asteroids

    CERN Document Server

    Skokos, C; Skokos, Ch.

    2001-01-01

    We study the spatial circular restricted problem of three bodies in the light of Nekhoroshev theory of stability over large time intervals. We consider in particular the Sun-Jupiter model and the Trojan asteroids in the neighborhood of the Lagrangian point $L_4$. We find a region of effective stability around the point $L_4$ such that if the initial point of an orbit is inside this region the orbit is confined in a slightly larger neighborhood of the equilibrium (in phase space) for a very long time interval. By combining analytical methods and numerical approximations we are able to prove that stability over the age of the universe is guaranteed on a realistic region, big enough to include one real asteroid. By comparing this result with the one obtained for the planar problem we see that the regions of stability in the two cases are of the same magnitude.

  14. New CCD photometry of asteroid (1028) Lydina

    Institute of Scientific and Technical Information of China (English)

    Yi-Bo Wang; Xiao-Bin Wang

    2012-01-01

    New CCD photometric observations for asteroid (1028) Lydina,carried out with the 1-m and 2.4-m telescopes at Yunnan Observatory from 2011 December 19 to 2012 February 3,are presented.Using the new light curves,the rotation period of 11.680±0.001 hours is derived with the Phase Dispersion Minimization (PDM) method.In addition,using the Amplitude-Aspect method,the elementary results of the pole orientation of asteroid (1028) Lydina are obtained:λp= 111°+4°-4°,βp= 31°+4°-5°.Meanwhile,the axial ratios of the tri-axial ellipsoid are estimated:a/b = 1.77+0.10-0.08and b/c = 1.17+0.07-0.09.

  15. Is 1220 Crocus a precessing, binary asteroid?

    Science.gov (United States)

    Binzel, R. P.

    1985-01-01

    Photoelectric data of the asteroid 1220 Crocus over a 13 night period in 1984 revealed the presence of two separate periods. The light curves were indicative of a precessing body, but not one in free precession due to motions induced by a collision. Closer examinations revealed periods of 30.7 and 7.9 hr with amplitudes of 0.87 and 0.15 mag, respectively. An analysis of the source of an external torque which could be causing a forced precession led to the hypothesis that 1220 Crocus has a satellite. Verification of the binary asteroid configuration will depend on more detailed light curves, the possible modulation of the shorter period by the longer, and possible use of the Space Telescope.

  16. Is 1220 Crocus a precessing, binary asteroid?

    Science.gov (United States)

    Binzel, R. P.

    1985-07-01

    Photoelectric data of the asteroid 1220 Crocus over a 13 night period in 1984 revealed the presence of two separate periods. The light curves were indicative of a precessing body, but not one in free precession due to motions induced by a collision. Closer examinations revealed periods of 30.7 and 7.9 hr with amplitudes of 0.87 and 0.15 mag, respectively. An analysis of the source of an external torque which could be causing a forced precession led to the hypothesis that 1220 Crocus has a satellite. Verification of the binary asteroid configuration will depend on more detailed light curves, the possible modulation of the shorter period by the longer, and possible use of the Space Telescope.

  17. Asteroids - the modern challenge of celestial dynamics

    Science.gov (United States)

    Dikova, Smiliana

    2002-11-01

    Among the most powerful statements in Science are those that mark absolute limits to knowledge. For example, Relativity and Quantum Theory touched the limits of speed and accuracy. Deterministic Chaos - the new scientific paradigma of our days, also falls in this class theories. Chaos means complexity in space and unpredictability in time. It shows the limit of our basic counting system and leads to a limited predictability of the long time dynamical evolution. Perhaps for that reason, in 1986 Sir James Lighthill remarked for all physicists: "We collectively wish to apologize for having misled the general educated public by spreading ideas about the determinism of systems satisfying Newton's laws of motion that, after 1960, were proved incorrect." Our main thesis is that Asteroid Dynamics is the arena where the drama Chaos versus predictability is initiated and developed. The aim of the present research is to show the way in which Deterministic Chaos restricts the long term dynamical predictability of asteroid motions.

  18. Catalogue of ISO LWS observations of asteroids

    CERN Document Server

    Hormuth, Felix

    2009-01-01

    (Abridged) The Long Wavelength Spectrometer (LWS) onboard the Infrared Space Observatory (ISO) observed the four large main-belt asteroids (1) Ceres, (2) Pallas, (4) Vesta, and (10) Hygiea multiple times. The photometric and spectroscopic data cover the wavelength range between 43 and 197 um, and are a unique dataset for future investigations and detailed characterisations of these bodies. The standard ISO archive products, produced through the last post-mission LWS pipeline, were still affected by instrument artefacts. Our goal was to provide the best possible data products to exploit the full scientific potential of these observations. We performed a refined reduction of all measurements, corrected for various instrumental effects, and re-calibrated the data. We outline the data reduction process and give an overview of the available data and the quality of the observations. We apply a thermophysical model to the flux measurements to derive far-IR based diameter and albedo values of the asteroids. The measu...

  19. Example Solar Electric Propulsion System asteroid tours using variational calculus

    Science.gov (United States)

    Burrows, R. R.

    1985-01-01

    Exploration of the asteroid belt with a vehicle utilizing a Solar Electric Propulsion System has been proposed in past studies. Some of those studies illustrated multiple asteroid rendezvous with trajectories obtained using approximate methods. Most of the inadequacies of those approximations are overcome in this paper, which uses the calculus of variations to calculate the trajectories and associated payloads of four asteroid tours. The modeling, equations, and solution techniques are discussed, followed by a presentation of the results.

  20. Design of MGA trajectories for main belt asteroid

    Institute of Scientific and Technical Information of China (English)

    崔祜涛; 乔栋; 崔平远; 栾恩杰

    2003-01-01

    Asteroid exploration is one of the most sophisticated missions currently being investigated. Gravityassist trajectories have proven valuable in interplanetary missions such as the Pioneer, Voyager and Galileo. In this paper, we design interplanetary trajectory for main belt asteroid exploration mission with the Mars gravityassist (MGA) using "pork chop" plots and patched-conic theory and give some initial valuable trajectory parameters on main belt asteroid exploration mission with MGA.

  1. Polarimetry of M-type asteroids

    Science.gov (United States)

    Gil-Hutton, R.

    2007-03-01

    Aims:Results of a polarimetric program at Complejo Astronómico El Leoncito (Casleo), San Juan, Argentina are presented. The aim of this campaign is to estimate the polarimetric properties of asteroids belonging to the X taxonomic class. In this paper results of the campaign for M-type objects are presented. Methods: The data have been obtained with Casprof and Torino polarimeters at the 2.15 m telescope. The Casprof polarimeter is a two-hole aperture polarimeter with rapid modulation and the Torino polarimeter is an instrument that allows simultaneous measurement of polarization in the U-, B-, V-, R-, and I-bands. Results: The campaign began in 2000, and data on a sample of 26 M-type asteroids were obtained. Most of these objects were polarimetricaly observed for the first time. Combining these data with those available in the literature, an estimate of the polarimetric parameters and albedo for 12 objects is presented. Furthermore, the data show that asteroids 21 Lutetia and 77 Frigga have a large inversion angle and 441 Bathilde a deep polarization minimum, implying a controversial taxonomic classification as M-type for these objects. Also, the polarimetric parameters estimated for the M-type asteroids showing in their spectra the 3 μm band and classified as W-type by Rivkin et al. (1995, Icarus, 117, 90; 2000, ApJ, 145, 351) could be different from those without that feature. Based on observations carried out at the Complejo Astronómico El Leoncito, operated under agreement between the Consejo Nacional de Investigaciones Científicas y Técnicas de la República Argentina, and the National Universities of La Plata, Córdoba and San Juan.

  2. CCD Photometry of Asteroid (147) Protogeneia

    Institute of Scientific and Technical Information of China (English)

    Xi-Liang Zhang; Xiao-Bin Wang; Li-Yun Zhang

    2006-01-01

    We measured the light-curve of the asteroid (147) Protogeneia in November 2004, with a CCD detector attached to the 1-meter telescope at the Yunnan Observatory, China. The synodic period and maximum amplitude of (147) at this apparition are 7.852 hours and 0.25 mag, respectively. The value of a/b for (147), from a preliminary estimation, is not less than 1.26:1.

  3. Simulations of asteroid impacts on water

    Science.gov (United States)

    Gisler, G. R.; Weaver, R. P.; Gittings, M. L.

    2002-05-01

    We have performed a series of two-dimensional and three-dimensional simulations of asteroid impacts into an ocean using the SAGE code from Los Alamos National Laboratory and Science Applications International Corporation. The SAGE code is a compressible Eulerian hydrodynamics code using continuous adaptive mesh refinement for following discontinuities with a fine grid while treating the bulk of the simulation more coarsely. We have used realistic equations of state for the atmosphere, sea water, the oceanic crust and mantle. In two dimensions, we threw asteroid impactors at 20 km/s vertically through an exponential atmosphere into a 5 km deep ocean. The impactors were composed of mantle material (3.32 g/cc) with diameters of 250m, 500m, and 1000m, chosen to compare with the previous work of Crawford and Mader. We also performed some runs with asteroids composed of iron (7.8 g/cc). Because some of the iron asteroids produced craters that penetrated the basalt crust, we included a layer of mantle material in all simulations. A vertical impact produces a large underwater cavity with nearly vertical walls followed by a collapse starting from the bottom and subsequent vertical jetting. Tsunamis up to a kilometer in initial height were generated and followed out to 100 km from the point of impact. In the three-dimensional run, an impactor of iron was thrown at 20 km/s at an angle of 45 degrees. Differences between this run and the vertical two-dimensional runs will be discussed.

  4. Consequences of Predicted or Actual Asteroid Impacts

    Science.gov (United States)

    Chapman, C. R.

    2003-12-01

    Earth impact by an asteroid could have enormous physical and environmental consequences. Impactors larger than 2 km diameter could be so destructive as to threaten civilization. Since such events greatly exceed any other natural or man-made catastrophe, much extrapolation is necessary just to understand environmental implications (e.g. sudden global cooling, tsunami magnitude, toxic effects). Responses of vital elements of the ecosystem (e.g. agriculture) and of human society to such an impact are conjectural. For instance, response to the Blackout of 2003 was restrained, but response to 9/11 terrorism was arguably exaggerated and dysfunctional; would society be fragile or robust in the face of global catastrophe? Even small impacts, or predictions of impacts (accurate or faulty), could generate disproportionate responses, especially if news media reports are hyped or inaccurate or if responsible entities (e.g. military organizations in regions of conflict) are inadequately aware of the phenomenology of small impacts. Asteroid impact is the one geophysical hazard of high potential consequence with which we, fortunately, have essentially no historical experience. It is thus important that decision makers familiarize themselves with the hazard and that society (perhaps using a formal procedure, like a National Academy of Sciences study) evaluate the priority of addressing the hazard by (a) further telescopic searches for dangerous but still-undiscovered asteroids and (b) development of mitigation strategies (including deflection of an oncoming asteroid and on- Earth civil defense). I exemplify these issues by discussing several representative cases that span the range of parameters. Many of the specific physical consequences of impact involve effects like those of other geophysical disasters (flood, fire, earthquake, etc.), but the psychological and sociological aspects of predicted and actual impacts are distinctive. Standard economic cost/benefit analyses may not

  5. Alien Asteroid Belt Compared to our Own

    Science.gov (United States)

    2005-01-01

    [figure removed for brevity, see original site] Figure 1: Band of Light Comparison This artist's concept illustrates what the night sky might look like from a hypothetical alien planet in a star system with an asteroid belt 25 times as massive as the one in our own solar system (alien system above, ours below; see Figure 1). NASA's Spitzer Space Telescope found evidence for such a belt around the nearby star called HD 69830, when its infrared eyes spotted dust, presumably from asteroids banging together. The telescope did not find any evidence for a planet in the system, but astronomers speculate one or more may be present. The movie begins at dusk on the imaginary world, when HD 69830, like our Sun, has begun to set over the horizon. Time is sped up to show the onset of night and the appearance of a brilliant band of light. This light comes from dust in a massive asteroid belt, which scatters sunlight. In our solar system, anybody observing the skies on a moonless night far from city lights can see the sunlight that is scattered by dust in our asteroid belt. Called zodiacal light and sometimes the 'false dawn,' this light appears as a dim band stretching up from the horizon when the Sun is about to rise or set. The light is faint enough that the disk of our Milky Way galaxy remains the most prominent feature in the sky. (The Milky Way disk is shown perpendicular to the zodiacal light in both pictures.) In contrast, the zodiacal light in the HD 69830 system would be 1,000 times brighter than our own, outshining even the Milky Way.

  6. 3382 Cassidy: A Short Period Asteroid

    Science.gov (United States)

    Risley, Ethan

    2013-04-01

    The asteroid 3382 Cassidy was observed from the Etscorn Campus Observatory (ECO, 2012) at New Mexico Institute of Mining and Technology in Socorro, NM, on nine nights over a span of 43 days in 2012 September-November. A bimodal synodic period of 4.254 ± 0.002 h and an amplitude of 0.15 ± 0.02 mag were obtained.

  7. Asteroids in the service of humanity

    CERN Document Server

    Crawford, Ian A

    2013-01-01

    There are at least three compelling reasons for the human race to initiate a major programme to explore and better understand the 'minor planets' of the Solar System: (1) Enhancing scientific knowledge; (2) Mitigating the impact hazard; and (3) Utilizing extraterrestrial resources. Strong synergies exist between all three. Moreover, all these activities would benefit from greater international cooperation in space exploration by the World's space agencies, and the recognition that asteroids are important targets for human and robotic exploration.

  8. Curation of Osiris-REx Asteroid Samples

    Science.gov (United States)

    Righter, K.; Nakamura-Messenger, K.; Lauretta, D. S.

    2013-01-01

    The New Frontiers mission, OSIRIS-REx, will encounter carbonaceous asteroid 101955 Bennu (1999 RQ36; [1]) in 2018, collect a sample and return it to Earth and deliver it to NASA-JSC for curation in 2023. The mission curation plan is being developed and an overview will be given, including the main elements of contamination control, sample recovery, cleanroom construction, and curation support once the sample is returned to Earth.

  9. A Probabilistic Asteroid Impact Risk Model

    Science.gov (United States)

    Mathias, Donovan L.; Wheeler, Lorien F.; Dotson, Jessie L.

    2016-01-01

    Asteroid threat assessment requires the quantification of both the impact likelihood and resulting consequence across the range of possible events. This paper presents a probabilistic asteroid impact risk (PAIR) assessment model developed for this purpose. The model incorporates published impact frequency rates with state-of-the-art consequence assessment tools, applied within a Monte Carlo framework that generates sets of impact scenarios from uncertain parameter distributions. Explicit treatment of atmospheric entry is included to produce energy deposition rates that account for the effects of thermal ablation and object fragmentation. These energy deposition rates are used to model the resulting ground damage, and affected populations are computed for the sampled impact locations. The results for each scenario are aggregated into a distribution of potential outcomes that reflect the range of uncertain impact parameters, population densities, and strike probabilities. As an illustration of the utility of the PAIR model, the results are used to address the question of what minimum size asteroid constitutes a threat to the population. To answer this question, complete distributions of results are combined with a hypothetical risk tolerance posture to provide the minimum size, given sets of initial assumptions. Model outputs demonstrate how such questions can be answered and provide a means for interpreting the effect that input assumptions and uncertainty can have on final risk-based decisions. Model results can be used to prioritize investments to gain knowledge in critical areas or, conversely, to identify areas where additional data has little effect on the metrics of interest.

  10. Naming asteroids for the popularisation of astronomy

    Science.gov (United States)

    Naranjo, O. A.

    2008-06-01

    We give a detailed description of how the naming of asteroids was used as a prize in competitions run by educational institutions and museums. There were two events, one in Venezuela and one in Brazil, which used this as an attractive alternative method for the popularisation of astronomy. The first competition, named Bautizo Espacial (Space Baptism), consisted of scientific stories written by high school students. The second, called Grande Desafio (Big Challenge), was a competition where teams of students were challenged to design and build prototype equipment to fight forest fires. Nationally, both events received wide publicity through newspapers, radio, TV and web pages, reaching many people in both countries. As part of both the events, several activities promoting the public knowledge of astronomy were held. The asteroids that were named in these competitions are just some of the many discovered in a search programme developed by the Group of Theoretical Astrophysics of University of Los Andes in Mérida, Venezuela (Grupo de Astrofisica Teórica de la Universidad de Los Andes) as a mainstream research programme. Finally, Asteroids for the Popularisation of Astronomy has been formally proposed to the IAU as a worldwide programme during the celebration of the International Year of Astronomy in 2009 (IYA2009).

  11. Dynamical evolution of the Cybele asteroids

    CERN Document Server

    Carruba, Valerio; Aljbaae, Safwan; Huaman, Mariela Espinoza

    2015-01-01

    The Cybele region, located between the 2J:-1A and 5J:-3A mean-motion resonances, is adjacent and exterior to the asteroid main belt. An increasing density of three-body resonances makes the region between the Cybele and Hilda populations dynamically unstable, so that the Cybele zone could be considered the last outpost of an extended main belt. The presence of binary asteroids with large primaries and small secondaries suggested that asteroid families should be found in this region, but only relatively recently the first dynamical groups were identified in this area. Among these, the Sylvia group has been proposed to be one of the oldest families in the extended main belt. In this work we identify families in the Cybele region in the context of the local dynamics and non-gravitational forces such as the Yarkovsky and stochastic YORP effects. We confirm the detection of the new Helga group at $\\simeq$3.65~AU, that could extend the outer boundary of the Cybele region up to the 5J:-3A mean-motion resonance. We o...

  12. The small binary asteroid (939) Isberga

    CERN Document Server

    Carry, B; Scheirich, P; Pravec, P; Molnar, L; Mottola, S; Carbognani, A; Jehin, E; Marciniak, A; Binzel, R P; DeMeo, F E; Birlan, M; Delbo, M; Barbotin, E; Behrend, R; Bonnardeau, M; Colas, F; Farissier, P; Fauvaud, M; Fauvaud, S; Gillier, C; Gillon, M; Hellmich, S; Hirsch, R; Leroy, A; Manfroid, J; Montier, J; Morelle, E; Richard, F; Sobkowiak, K; Strajnic, J; Vachier, F

    2014-01-01

    In understanding the composition and internal structure of asteroids, their density is perhaps the most diagnostic quantity. We aim here to characterize the surface composition, mutual orbit, size, mass, and density of the small main-belt binary asteroid (939) Isberga. For that, we conduct a suite of multi-technique observations, including optical lightcurves over many epochs, near-infrared spectroscopy, and interferometry in the thermal infrared. We develop a simple geometric model of binary systems to analyze the interferometric data in combination with the results of the lightcurve modeling. From spectroscopy, we classify Ibserga as a Sq-type asteroid, consistent with the albedo of 0.14$^{+0.09}_{-0.06}$ (all uncertainties are reported as 3-$\\sigma$ range) we determine (average albedo of S-types is 0.197 $\\pm$ 0.153, Pravec et al., 2012, Icarus 221, 365-387). Lightcurve analysis reveals that the mutual orbit has a period of 26.6304 $\\pm$ 0.0001 h, is close to circular, and has pole coordinates within 7 deg...

  13. How Many Ore-Bearing Asteroids?

    CERN Document Server

    Elvis, Martin

    2013-01-01

    A simple formalism is presented to assess how many asteroids contain ore, i.e. commercially profitable material, and not merely a high concentration of a resource. I apply this formalism to two resource cases: platinum group metals (PGMs) and water. Assuming for now that only Ni-Fe asteroids are of interest for PGMs, then 1% of NEOs are rich in PGMs. The dearth of ultra-low delta-v (= US$1 B and the population of near-Earth objects (NEOs) larger than 100 m diameter is ~20,000 (Mainzer et al. 2011) the total population of PGM ore-bearing NEOs is roughly 10. I stress that this is a conservative and highly uncertain value. For example, an order of magnitude increase in PGM ore-bearing NEOs occurs if delta-v can as large as 5.7 km s-1. Water ore for utilization in space is likely to be found in ~1/1100 NEOs. NEOs as small as 18 m diameter can be water-ore-bodies because of the high richness of water (~20%) expected in ~25% of carbonaceous asteroids, bringing the number of water-ore-bearing NEOs to ~9000 out of th...

  14. How to find metal-rich asteroids

    CERN Document Server

    Harris, Alan W

    2014-01-01

    The metal content of asteroids is of great interest, not only for theories of their origins and the evolution of the solar system but, in the case of near-Earth objects (NEOs), also for impact mitigation planning and endeavors in the field of planetary resources. However, since the reflection spectra of metallic asteroids are largely featureless, it is difficult to identify them and relatively few are known. We show how data from the Wide-field Infrared Survey Explorer (WISE)/NEOWISE thermal-infrared survey and similar surveys, fitted with a simple thermal model, can reveal objects likely to be metal rich. We provide a list of candidate metal-rich NEOs. Our results imply that future infrared surveys with the appropriate instrumentation could discover many more metal-rich asteroids, providing valuable data for assessment of the impact hazard and the potential of NEOs as reservoirs of vital materials for future interplanetary space activities and, eventually perhaps, for use on Earth.

  15. Formation and Evolution of Binary Asteroids

    CERN Document Server

    Walsh, Kevin J

    2015-01-01

    Satellites of asteroids have been discovered in nearly every known small body population, and a remarkable aspect of the known satellites is the diversity of their properties. They tell a story of vast differences in formation and evolution mechanisms that act as a function of size, distance from the Sun, and the properties of their nebular environment at the beginning of Solar System history and their dynamical environment over the next 4.5 Gyr. The mere existence of these systems provides a laboratory to study numerous types of physical processes acting on asteroids and their dynamics provide a valuable probe of their physical properties otherwise possible only with spacecraft. Advances in understanding the formation and evolution of binary systems have been assisted by: 1) the growing catalog of known systems, increasing from 33 to nearly 250 between the Merline et al. (2002) Asteroids III chapter and now, 2) the detailed study and long-term monitoring of individual systems such as 1999 KW4 and 1996 FG3, 3...

  16. The Cratering History of Asteroid (2867) Steins

    CERN Document Server

    Marchi, S; Kueppers, M; Marzari, F; Davidsson, B; Keller, H U; Besse, S; Lamy, P; Mottola, S; Massironi, M; Cremonese, G

    2010-01-01

    The cratering history of main belt asteroid (2867) Steins has been investigated using OSIRIS imagery acquired during the Rosetta flyby that took place on the 5th of September 2008. For this purpose, we applied current models describing the formation and evolution of main belt asteroids, that provide the rate and velocity distributions of impactors. These models coupled with appropriate crater scaling laws, allow the cratering history to be estimated. Hence, we derive Steins' cratering retention age, namely the time lapsed since its formation or global surface reset. We also investigate the influence of various factors -like bulk structure and crater erasing- on the estimated age, which spans from a few hundred Myrs to more than 1Gyr, depending on the adopted scaling law and asteroid physical parameters. Moreover, a marked lack of craters smaller than about 0.6km has been found and interpreted as a result of a peculiar evolution of Steins cratering record, possibly related either to the formation of the 2.1km ...

  17. The preventive destruction of a hazardous asteroid

    Science.gov (United States)

    Aleksandrova, A. G.; Galushina, T. Yu.; Prishchepenko, A. B.; Kholshevnikov, K. V.; Chechetkin, V. M.

    2016-06-01

    One means of countering a hazardous asteroid is discussed: destruction of the object using a nuclear charge. Explosion of such an asteroid shortly before its predicted collision would have catastrophic consequences, with numerous highly radioactive fragments falling onto the Earth. The possibility of exploding the asteroid several years before its impact is also considered. Such an approach is made feasible because the vast majority of hazardous objects pass by the Earth several times before colliding with it. Computations show that, in the 10 years following the explosion, only a negligible number of fragments fall onto the Earth, whose radioactivity has substantially reduced during this time. In most cases, none of these fragments collides with the Earth. Thus, this proposed method for eliminating a threat from space is reasonable in at least two cases: when it is not possible to undergo a soft removal of the object from the collisional path, and to destroy objects that are continually returning to near-Earth space and require multiple removals from hazardous orbits.

  18. Spacewatch discovery of near-Earth asteroids

    Science.gov (United States)

    Gehrels, Tom

    1992-01-01

    Our overall scientific goal is to survey the solar system to completion - that is, to find the various populations and to study their statistics, interrelations, and origins. The practical benefit to SERC is that we are finding Earth-approaching asteroids that are accessible for mining. Our system can detect Earth-approachers in the 1-km size range even when they are far away, and can detect smaller objects when they are moving rapidly past Earth. Until Spacewatch, the size range of 6-300 meters in diameter for the near-Earth asteroids was unexplored. This important region represents the transition between the meteorites and the larger observed near-Earth asteroids. One of our Spacewatch discoveries, 1991 VG, may be representative of a new orbital class of object. If it is really a natural object, and not man-made, its orbital parameters are closer to those of the Earth than we have seen before; its delta V is the lowest of all objects known thus far. We may expect new discoveries as we continue our surveying, with fine-tuning of the techniques.

  19. Photometry and models of selected main belt asteroids: IX. Introducing interactive service for asteroid models (ISAM)

    DEFF Research Database (Denmark)

    Marciniak, A.; Bartczak, P.; Santana-Ros, T.

    2012-01-01

    from other observing/modelling techniques, we created an on-line service where we allow the inversion models to be orientated interactively. Results. Our sample of objects is quite representative, containing both relatively fast and slow rotators with highly and lowly inclined spin axes. With this work...... occultations, or space probe imaging. Aims. During our ongoing work to increase the set of asteroids with known spin and shape parameters, there appeared a need for displaying the model plane-of-sky orientations for specific epochs to compare models from different techniques. It would also be instructive...... to be able to track how the complex lightcurves are produced by various asteroid shapes. Methods. Basing our analysis on an extensive photometric observational dataset, we obtained eight asteroid models with the convex lightcurve inversion method. To enable comparison of the photometric models with those...

  20. Polarization of asteroid (387) Aquitania: the newest member of a class of large inversion angle asteroids

    CERN Document Server

    Masiero, Joseph

    2008-01-01

    We present new imaging polarimetric observations of two Main Belt asteroids, (234) Barbara and (387) Aquitania, taken in the first half of 2008 using the Dual-Beam Imaging Polarimeter on the University of Hawaii 2.2 meter telescope, located on Mauna Kea, Hawaii. Barbara had been previously shown to exhibit a very unusual polarization-phase curve by Cellino, et al. (2006). Our observations confirm this result and add Aquitania to the growing class of large inversion angle objects. Interestingly, these asteroids show spinel features in their IR spectra suggesting a mineralogical origin to the phase angle-dependent polarimetric features. As spinel is associated with calcium-aluminum-rich inclusions and carbonaceous chondrites, these large inversion angle asteroids may represent some of the oldest surfaces in the solar system. Circular as well as linear polarization measurements were obtained but circular polarization was not detected.

  1. The Nature of C Asteroid Regolith from Meteorite Observations

    Science.gov (United States)

    Zolensky, M.; Mikouchi, T.; Hagiya, K.; Ohsumi, K.; Komatsu, M.; Jenniskens, P.; Le, L.; Yin, Q.-Z; Kebukawa, Y.; Fries, M.

    2013-01-01

    Regolith from C (and related) asteroid bodies are a focus of the current missions Dawn at Ceres, Hayabusa 2 and OSIRIS REx. An asteroid as large as Ceres is expected to be covered by a mature regolith, and as Hayabusa demonstrated, flat and therefore engineeringly-safe ponded deposits will probably be the sampling sites for both Hayabusa 2 and OSIRIS REx. Here we examine what we have learned about the mineralogy of fine-grained asteroid regolith from recent meteorite studies and the examination of the samples harvested from asteroid Itokawa by Hayabusa.

  2. A fast ellipsoid model for asteroids inverted from lightcurves

    Institute of Scientific and Technical Information of China (English)

    Xiao-Ping Lu; Hai-Bin Zhao; Zhong You

    2013-01-01

    Research about asteroids has recently attracted more and more attention,especially focusing on their physical structures,such as their spin axis,rotation period and shape.The long distance between observers on Earth and asteroids makes it impossible to directly calculate the shape and other parameters of asteroids,with the exception of Near Earth Asteroids and others that have passed by some spacecrafts.Photometric measurements are still generally the main way to obtain research data on asteroids,i.e.the lightcurves recording the brightness and positions of asteroids.Supposing that the shape of the asteroid is a triaxial ellipsoid with a stable spin,a new method is presented in this article to reconstruct the shape models of asteroids from the lightcurves,together with other physical parameters.By applying a special curvature function,the method calculates the brightness integration on a unit sphere and Lebedev quadrature is employed for the discretization.Finally,the method searches for the optimal solution by the Levenberg-Marquardt algorithm to minimize the residual of the brightness.By adopting this method,not only can related physical parameters of asteroids be obtained at a reasonable accuracy,but also a simple shape model of an ellipsoid can be generated for reconstructing a more sophisticated shape model.

  3. Thermal History of Near-Earth Asteroids: Implications for OSIRIS-REx Asteroid Sample Return

    Science.gov (United States)

    Springmann, Alessondra; Lauretta, Dante S.

    2016-10-01

    The connection between orbital and temperature history of small Solar System bodies has only been studied through modeling. The upcoming OSIRIS-REx asteroid sample return mission provides an opportunity to connect thermal modeling predictions with laboratory studies of meteorites to predict past heating and thus dynamical histories of bodies such as OSIRIS-REx mission target asteroid (101955) Bennu. Bennu is a desirable target for asteroid sample return due to its inferred primitive nature, likely 4.5 Gyr old, with chemistry and mineralogy established in the first 10 Myr of solar system history (Lauretta et al. 2015). Delbo & Michel (2011) studied connections between the temperature and orbital history of Bennu. Their results suggest that the surface of Bennu (assuming no regolith turnover) has a 50% probability of being heated to 500 K in the past. Further, the Delbo & Michel simulations show that the temperature within the asteroid below the top layer of regolith could remain at temperatures ~100 K below that of the surface. The Touch-And-Go Sample Acquisition Mechanism on OSIRIS-REx could access both the surface and near surface regolith, collecting primitive asteroid material for study in Earth-based laboratories in 2023. To quantify the effects of thermal metamorphism on the Bennu regolith, laboratory heating experiments on carbonaceous chondrite meteorites with compositions likely similar to that of Bennu were conducted from 300-1200 K. These experiments show mobilization and volatilization of a suite of labile elements (sulfur, mercury, arsenic, tellurium, selenium, antimony, and cadmium) at temperatures that could be reached by asteroids that cross Mercury's orbit. We are able to quantify element loss with temperature for several carbonaceous chondrites and use these results to constrain past orbital histories of Bennu. When OSIRIS-REx samples arrive for analysis we will be able to measure labile element loss in the material, determine maximum past

  4. Rotation Induced Disruption of Cohesive Asteroids

    Science.gov (United States)

    Sanchez Lana, Diego; Scheeres, D. J.

    2013-10-01

    We use a Soft-Sphere Discrete Element Method (SSDEM) code to study the evolution of self-gravitating cohesive granular aggregates that are spun to disruption as a proxy to "rubble-pile" asteroids. Calculations have shown that the fine regolith in asteroids and molecular Van der Waals forces together may act as a cohesive matrix that provides enough structural strength to hold small NEAs together even at the observed high spin rates. With this in mind we have implemented cohesive forces between the large 10 m) particles that form our aggregates; its strength being controlled by the mean particle size of the matrix. The addition of rolling friction also has allowed us to obtain cohesionless aggregates with friction angles of at least 35° as measured by the Drucker-Prager yield criterion. A series of experiments were run with the code, keeping the size, density and number of grains constant while increasing the cohesive strength of the matrix holding the grains in place. It can be shown, through a scaling analysis, that when the cohesive strength between rubble pile components is increased by a factor of f, that the effective size of the asteroid being modeled will decrease by a factor of 1/√f. To evaluate this we ran a series of 12 cases with increasing cohesive strength, effectively modeling rubble piles of size from 0.1 km up to 100 km with a constant cohesive strength of 25 Pa. Some of our main results are as follows: 1. results from simulations are compatible with a simple model of asteroid strength that predicts, in the cohesion dominated case, that the spin rate for fission is inversely proportional to the size of the asteroid; 2. aggregates may disrupt by shedding or fission, depending on the cohesive strength and the size of the aggregate (shape and heterogeneity factors have not yet been considered); 3. disruption by fission is more likely for small aggregates than for larger aggregates with the same cohesive strength. Further results with spherical and a

  5. Deflection by kinetic impact: Sensitivity to asteroid properties

    Science.gov (United States)

    Bruck Syal, Megan; Michael Owen, J.; Miller, Paul L.

    2016-05-01

    Impacting an asteroid with a spacecraft traveling at high speed delivers an impulsive change in velocity to the body. In certain circumstances, this strategy could be used to deflect a hazardous asteroid, moving its orbital path off of an Earth-impacting course. However, the efficacy of momentum delivery to asteroids by hypervelocity impact is sensitive to both the impact conditions (particularly velocity) and specific characteristics of the target asteroid. Here we numerically model asteroid response to kinetic impactors under a wide range of initial conditions, using an Adaptive Smoothed Particle Hydrodynamics code. Impact velocities spanning 1-30 km/s were investigated, yielding, for a particular set of assumptions about the modeled target material, a power-law dependence consistent with a velocity-scaling exponent of μ = 0.44. Target characteristics including equation of state, strength model, porosity, rotational state, and shape were varied, and corresponding changes in asteroid response were documented. The kinetic-impact momentum-multiplication factor, β, decreases with increasing asteroid cohesion and increasing porosity. Although increased porosity lowers β, larger porosities result in greater deflection velocities, as a consequence of reduced target masses for asteroids of fixed size. Porosity also lowers disruption risk for kinetic impacts near the threshold of disruption. Including fast (P = 2.5 h) and very fast (P = 100 s) rotation did not significantly alter β but did affect the risk of disruption by the impact event. Asteroid shape is found to influence the efficiency of momentum delivery, as local slope conditions can change the orientation of the crater ejecta momentum vector. These results emphasize the need for asteroid characterization studies to bracket the range of target conditions expected at near-Earth asteroids while also highlighting some of the principal uncertainties associated with the kinetic-impact deflection strategy.

  6. BAOBAB (Big And Outrageously Bold Asteroid Belt) Project

    Science.gov (United States)

    Mcfadden, L. A.; Thomas, C. A; Englander, J. A.; Ruesch, O.; Hosseini, S.; Goossens, S. J.; Mazarico, E. M.; Schmerr, N.

    2017-01-01

    One of the intriguing results of NASA's Dawn mission is the composition and structure of the Main Asteroid Belt's only known dwarf planet, Ceres [1]. It has a top layer of dehydrated clays and salts [2] and an icy-rocky mantle [3,4]. It is widely known that the asteroid belt failed to accrete as a planet by resonances between the Sun and Jupiter. About 20-30 asteroids >100 km diameter are probably differentiated protoplanets [5]. 1) how many more and which ones are fragments of protoplanets? 2) How many and which ones are primordial rubble piles left over from condensation of the solar nebula? 3) How would we go about gaining better and more complete characterization of the mass, interior structure and composition of the Main Belt asteroid population? 4) What is the relationship between asteroids and ocean worlds? Bulk parameters such as the mass, density, and porosity, are important to characterize the structure of any celestial body, and for asteroids in particular, they can shed light on the conditions in the early solar system. Asteroid density estimates exist but currently they are often based on assumed properties of taxonomic classes, or through astronomical survey data where interactions with asteroids are weak at best resulting in large measurement uncertainty. We only have direct density estimates from spacecraft encounters for a few asteroids at this time. Knowledge of the asteroids is significant not only to understand their role in solar system workings, but also to assess their potential as space resources, as impact hazards on Earth, or even as harboring life forms. And for the distant future, we want to know if the idea put forth in a contest sponsored by Physics Today, to surface the asteroids into highly reflecting, polished surfaces and use them as a massively segmented mirror for astrophysical exploration [6], is feasible.

  7. Asteroid Redirect Crewed Mission Nominal Design and Performance

    Science.gov (United States)

    Condon, Gerald; williams, Jacob

    2014-01-01

    In 2010, the President announced that, in 2025, the U.S. intended to launch a human mission to an asteroid [1]. This announcement was followed by the idea of a Capability Driven Framework (CDF) [2], which is based on the idea of evolving capabilities from less demanding to more demanding missions to multiple possible destinations and with increased flexibility, cost effectiveness and sustainability. Focused missions, such as a NASA inter-Center study that examined the viability and implications of sending a crew to a Near Earth Asteroid (NEA) [3], provided a way to better understand and evaluate the utility of these CDF capabilities when applied to an actual mission. The long duration of the NEA missions were contrasted with a concept described in a study prepared for the Keck Institute of Space Studies (KISS) [4] where a robotic spacecraft would redirect an asteroid to the Earth-Moon vicinity, where a relatively short duration crewed mission could be conducted to the captured asteroid. This mission concept was included in the National Aeronautics and Space Administration (NASA) fiscal year 2014 budget request, as submitted by the NASA Administrator [5]. NASA studies continued to examine the idea of a crewed mission to a captured asteroid in the Earth-Moon vicinity. During this time was an announcement of NASA's Asteroid Grand Challenge [6]. Key goals for the Asteroid Grand Challenge are to locate, redirect, and explore an asteroid, as well as find and plan for asteroid threats. An Asteroid Redirect Mission (ARM) study was being conducted, which supports this Grand Challenge by providing understanding in how to execute an asteroid rendezvous, capture it, and redirect it to Earth-Moon space, and, in particular, to a distant retrograde orbit (DRO). Subsequent to the returning of the asteroid to a DRO, would be the launch of a crewed mission to rendezvous with the redirected asteroid. This report examines that crewed mission by assessing the Asteroid Redirect Crewed

  8. Albedo and Diameter Distributions of Asteroid Families Using the Spitzer Asteroid Catalog

    NARCIS (Netherlands)

    Enga, Marie-Therese; Trilling, D.; Mueller, M.; Wasserman, L.; Sykes, M.; Blaylock, M.; Stansberry, J.; Bhattacharya, B.; Spahr, T.

    2009-01-01

    The Spitzer Asteroid Catalog contains flux measurements of asteroidsserendipitously observed in publicly available Spitzer data. At present,this catalog contains some 10,000 measurements at 24 microns only, andwill ultimately contain 100,000 measurements or more. These measurements, along with with

  9. Earth-approaching asteroids: Populations, origin, and compositional types

    Science.gov (United States)

    Shoemaker, E. M.; Helin, E. F.

    1978-01-01

    Origin, physical properties, and discovery history of smaller asteroids are reviewed. They appear to link the main belt objects, namely the comets and meteorites. Physical observations suggest that a wide variety of compositional types are represented among the near-earth asteroids; the apparent rarity of carbonaceous objects is stated.

  10. Compositional differences between meteorites and near-Earth asteroids.

    Science.gov (United States)

    Vernazza, P; Binzel, R P; Thomas, C A; DeMeo, F E; Bus, S J; Rivkin, A S; Tokunaga, A T

    2008-08-14

    Understanding the nature and origin of the asteroid population in Earth's vicinity (near-Earth asteroids, and its subset of potentially hazardous asteroids) is a matter of both scientific interest and practical importance. It is generally expected that the compositions of the asteroids that are most likely to hit Earth should reflect those of the most common meteorites. Here we report that most near-Earth asteroids (including the potentially hazardous subset) have spectral properties quantitatively similar to the class of meteorites known as LL chondrites. The prominent Flora family in the inner part of the asteroid belt shares the same spectral properties, suggesting that it is a dominant source of near-Earth asteroids. The observed similarity of near-Earth asteroids to LL chondrites is, however, surprising, as this meteorite class is relatively rare ( approximately 8 per cent of all meteorite falls). One possible explanation is the role of a size-dependent process, such as the Yarkovsky effect, in transporting material from the main belt.

  11. Taxonomic Classification of Asteroids via Broadband Near-Infrared Photometry

    NARCIS (Netherlands)

    Petersen, Eric; Thomas, C.; Trilling, D.; Emery, J.; Delbo, M.; Mueller, M.; Dave, R.

    2010-01-01

    For faint asteroids, it is not practical to obtain near-infrared spectra. However, it may be possible to use broadband photometry to infer spectral classifications and study composition. As a test of this, we processed SpeX near-infrared asteroid spectral data to simulate colors that would be obtain

  12. Modeling Asteroid Dynamics using AMUSE: First Test Cases

    NARCIS (Netherlands)

    Frantseva, Kateryna; Mueller, Michael; van der Tak, Floris; Helmich, Frank P.

    2015-01-01

    We are creating a dynamic model of the current asteroid population. The goal is to reproduce measured impact rates in the current Solar System, from which we'll derive delivery rates of water and organic material by tracing low-albedo C-class asteroids (using the measured albedo distribution from WI

  13. 78 FR 31977 - NASA Asteroid Initiative Call for Ideas

    Science.gov (United States)

    2013-05-28

    ... SPACE ADMINISTRATION NASA Asteroid Initiative Call for Ideas AGENCY: National Aeronautics and Space... announces a public forum to provide a status on the agency's asteroid initiative planning and to encourage...: This meeting will be streamed live online. Viewing options will be posted at...

  14. Physical Properties of Near-Earth Asteroid 2011 MD

    NARCIS (Netherlands)

    Mommert, M.; Farnocchia, D.; Hora, J. L.; Chesley, S. R.; Trilling, D. E.; Chodas, P. W.; Mueller, M.; Harris, A. W.; Smith, H. A.; Fazio, G. G.

    2014-01-01

    We report on observations of near-Earth asteroid 2011 MD with the Spitzer Space Telescope. We have spent 19.9 h of observing time with channel 2 (4.5 {\\mu}m) of the Infrared Array Camera and detected the target within the 2{\\sigma} positional uncertainty ellipse. Using an asteroid thermophysical mod

  15. Optimised low-thrust mission to the Atira asteroids

    Science.gov (United States)

    Di Carlo, Marilena; Romero Martin, Juan Manuel; Ortiz Gomez, Natalia; Vasile, Massimiliano

    2017-04-01

    Atira asteroids are recently-discovered celestial bodies characterised by orbits lying completely inside the heliocentric orbit of the Earth. The study of these objects is difficult due to the limitations of ground-based observations: objects can only be detected when the Sun is not in the field of view of the telescope. However, many asteroids are expected to exist in the inner region of the Solar System, many of which could pose a significant threat to our planet. In this paper, a small, low-cost, mission to visit the known Atira asteroids and to discover new Near Earth Asteroids (NEA) is proposed. The mission is realised using electric propulsion. The trajectory is optimised to maximise the number of visited asteroids of the Atira group using the minimum propellant consumption. During the tour of the Atira asteroids an opportunistic NEA discovery campaign is proposed to increase our knowledge of the asteroid population. The mission ends with a transfer to an orbit with perihelion equal to Venus's orbit radius. This orbit represents a vantage point to monitor and detect asteroids in the inner part of the Solar System and provide early warning in the case of a potential impact.

  16. Density and Macroporosity Distribution of Near Earth Asteroids

    Science.gov (United States)

    Dotson, Jessie L.; Mathias, Donovan

    2017-01-01

    The density of near earth asteroids is a fundamental property which can illuminate the structure of the asteroid, provide clues about it’s collisional history and is key in assessing the hazard of an impact of an NEA with Earth. A low density can be indicative of a rubble pile structure whereas a higher density can imply a monolith and/or a higher metal content. Unfortunately, measuring the density of asteroids is extremely difficult, has only been attempted for a tiny fraction of NEAs and usually results in measurements with large uncertainties. In the absence of density measurements for a specific object, understanding the range and distribution of likely densities can allow for probabilistic assessments of the population and facilitate estimates of the range of reasonable masses for a specific object. We have developed a candidate macroporosity distribution for near earth asteroids based on measurements of meteorite densities and asteroid densities. The macroporosity of an asteroid can be used to aid extrapolation from meteorite physical properties to asteroid physical properties. In addition, we discuss estimating an asteroid density distribution from the macroporosity distribution.

  17. A Targeted Search for Trojan Asteroids in Kepler Lightcurves

    Science.gov (United States)

    Bordenave, David; Ballard, Sarah

    2015-01-01

    'Trojan' asteroids, or asteroids trapped in stable gravitational positions preceding and trailing a planet in its orbit, accompany almost every planet of our Solar System. They were captured into their current locations in the early stages of our solar system's formation, and their presence hints at the dynamical history of bodies orbiting the Sun. However, we have no reason to assume that our own planets are alone in possessing Trojan asteroids. NASA's Kepler mission, launched in 2009, has been instrumental in the recent search for exoplanets. It has identified thousands of new worlds to date. However, exo-Trojan asteroids have as-yet eluded detection. If asteroids are captured at both Lagrangian points, their folded transit signature is not strictly periodic (since transits occur 1/6th of the planetary period before and after transit), and may be missed by traditional search algorithms. Our targeted search, at the predicted times of transit, is best suited for identifying candidate Trojans. Moreover, we have focused our investigation upon the set of Kepler Objects of Interest (KOIs) that we predict will be most fruitful for Trojan detection. However, if we are unable to detect these Trojan asteroids, we will be able to set limiting constraints on the presence of asteroids in exoplanetary systems. Observations of these Trojan asteroids, or the lack thereof, would give insight to the evolution and migration models of these systems.

  18. Near Earth Asteroids: A Classification System According to Their Shapes

    Science.gov (United States)

    Acevedo, R. D.; Rocca, M.; Rabassa, J.; Ponce, J. F.; Stinco, S.

    2012-09-01

    A new way to classify Near Earth Asteroids (NEAs) according to their shapes is proposed. This classification is based on the asteroid roundness and sphericity in the same way that it is used in geological sciences to describe clasts in mechanical sedimentary rocks.

  19. Absolute magnitudes of asteroids and a revision of asteroid albedo estimates from WISE thermal observations

    Science.gov (United States)

    Pravec, Petr; Harris, Alan W.; Kušnirák, Peter; Galád, Adrián; Hornoch, Kamil

    2012-09-01

    We obtained estimates of the Johnson V absolute magnitudes (H) and slope parameters (G) for 583 main-belt and near-Earth asteroids observed at Ondřejov and Table Mountain Observatory from 1978 to 2011. Uncertainties of the absolute magnitudes in our sample are estimates reported by asteroid surveys. With our photometric H and G data, we revised the preliminary WISE albedo estimates made by Masiero et al. (Masired, J.R. et al. [2011]. Astrophys. J. 741, 68-89) and Mainzer et al. (Mainzer, A. et al. [2011b]. Astrophys. J. 743, 156-172) for asteroids in our sample. We found that the mean geometric albedo of Tholen/Bus/DeMeo C/G/B/F/P/D types with sizes of 25-300 km is pV = 0.057 with the standard deviation (dispersion) of the sample of 0.013 and the mean albedo of S/A/L types with sizes 0.6-200 km is 0.197 with the standard deviation of the sample of 0.051. The standard errors of the mean albedos are 0.002 and 0.006, respectively; systematic observational or modeling errors can predominate over the quoted formal errors. There is apparent only a small, marginally significant difference of 0.031 ± 0.011 between the mean albedos of sub-samples of large and small (divided at diameter 25 km) S/A/L asteroids, with the smaller ones having a higher albedo. The difference will have to be confirmed and explained; we speculate that it may be either a real size dependence of surface properties of S type asteroids or a small size-dependent bias in the data (e.g., a bias towards higher albedos in the optically-selected sample of asteroids). A trend of the mean of the preliminary WISE albedo estimates increasing with asteroid size decreasing from D ∼ 30 down to ∼5 km (for S types) showed in Mainzer et al. (Mainzer, A. et al. [2011a]. Astrophys. J. 741, 90-114) appears to be mainly due to the systematic bias in the MPCORB absolute magnitudes that progressively increases with H in the corresponding range H = 10-14.

  20. Volcanic processes on early-forming asteroids.

    Science.gov (United States)

    Wilson, L.; Keil, K.

    2011-12-01

    A variety of meteorite groups represent samples of asteroids that formed while 26Al was still the dominant heat source in Solar System materials. These bodies differentiated to varying degrees beyond the temperature of FeNi-FeS melting, with sufficient silicate melting to allow metal core formation. The silicate melts segregated upward from the interiors to suffer various fates: intrusion at shallow levels, eruption onto the surface, or ejection into space in explosive eruptions in which the eruption speed exceeded the escape speed. These three styles of plutonic/volcanic activity were not mutually exclusive; their relative importance was a function of asteroid size and composition, with the major compositional factor being the total available volatile inventory. Much research has been concerned with whether silicate melts were extracted from the mantle during the period of mantle heating or while the mantle was cooling after reaching its peak temperature and degree of partial melting (a "magma ocean" stage). Traditionally, the relevant arguments have been based on the petrology and geochemistry of the meteorites sampling these bodies. Instead, we focus on the fluid dynamic aspects of eruption and intrusion processes and show how these impose additional limitations on various aspects of the igneous activity. For example, 40% melting of bodies the size of 4 Vesta (~250 km radius) and the Ureilite Parent Body (UPB, ~100 km radius) over the course of a 0.5 Ma heating period represent melt volume production rates of ~350 and 20 cubic meters per second, respectively, in each of what we demonstrate should have been ~4 volcanic provinces on each body. All differentiated asteroids must of necessity have had a surface layer ~10 km thick at sub-solidus temperatures controlled by conductive cooling. To erupt magma at the surface (or intrude magma at very shallow depth) through such a crust would have required the propagation of dikes within which the combination of dike width

  1. Why we need asteroid sample return mission?

    Science.gov (United States)

    Barucci, Maria Antonietta

    2016-07-01

    Small bodies retain evidence of the primordial solar nebula and the earliest solar system processes that shaped their evolution. They may also contain pre-solar material as well as complex organic molecules, which could have a major role to the development of life on Earth. For these reasons, asteroids and comets have been targets of interest for missions for over three decades. However, our knowledge of these bodies is still very limited, and each asteroid or comet visited by space mission has revealed unexpected scientific results, e.g. the structure and nature of comet 67P/Churyumov-Gerasimenko (67P/C-G) visited by the Rosetta mission. Only in the laboratory can instruments with the necessary precision and sensitivity be applied to individual components of the complex mixture of materials that forms a small body regolith, to determine their precise chemical and isotopic composition. Such measurements are vital for revealing the evidence of stellar, interstellar medium, pre-solar nebula and parent body processes that are retained in primitive material, unaltered by atmospheric entry or terrestrial contamination. For those reasons, sample return missions are considered a high priority by a number of the leading space agencies. Abundant within the inner Solar System and the main impactors on terrestrial planets, small bodies may have been the principal contributors of the water and organic material essential to create life on Earth. Small bodies can therefore be considered to be equivalent to DNA for unravelling our solar system's history, offering us a unique window to investigate both the formation of planets and the origin of life. A sample return mission to a primitive Near-Earth Asteroid (NEA) has been study at ESA from 2008 in the framework of ESA's Cosmic Vision (CV) programme, with the objective to answer to the fundamental CV questions "How does the Solar System work?" and "What are the conditions for life and planetary formations?". The returned material

  2. Jovian Early Bombardment: planetesimal erosion in the inner asteroid belt

    CERN Document Server

    Turrini, Diego; Magni, Gianfranco

    2012-01-01

    The asteroid belt is an open window on the history of the Solar System, as it preserves records of both its formation process and its secular evolution. The progenitors of the present-day asteroids formed in the Solar Nebula almost contemporary to the giant planets. The actual process producing the first generation of asteroids is uncertain, strongly depending on the physical characteristics of the Solar Nebula, and the different scenarios produce very diverse initial size-frequency distributions. In this work we investigate the implications of the formation of Jupiter, plausibly the first giant planet to form, on the evolution of the primordial asteroid belt. The formation of Jupiter triggered a short but intense period of primordial bombardment, previously unaccounted for, which caused an early phase of enhanced collisional evolution in the asteroid belt. Our results indicate that this Jovian Early Bombardment caused the erosion or the disruption of bodies smaller than a threshold size, which strongly depen...

  3. Asteroid spin-axis longitudes from the Lowell Observatory database

    CERN Document Server

    Bowell, E; Wasserman, L H; Muinonen, K; Penttilä, A; Trilling, D E

    2013-01-01

    By analyzing brightness variation with ecliptic longitude and using the Lowell Observatory photometric database, we estimate spin-axis longitudes for more than 350 000 asteroids. Hitherto, spin-axis longitude estimates have been made for fewer than 200 asteroids. We investigate longitude distributions in different dynamical groups and asteroid families. We show that asteroid spin-axis longitudes are not isotropically distributed as previously considered. We find that the spin-axis longitude distribution for main-belt asteroids is clearly non-random, with an excess of longitudes from the interval 30{\\deg}-110{\\deg} and a paucity between 120{\\deg}-180{\\deg}. The explanation of the non-isotropic distribution is unknown at this point. Further studies have to be conducted to determine if the shape of the distribution can be explained by observational bias, selection effects, a real physical process or other mechanism.

  4. Landslides and Mass Shedding on Spinning Spheroidal Asteroids

    CERN Document Server

    Scheeres, D J

    2014-01-01

    Conditions for regolith landslides to occur on spinning, gravitating spheroidal asteroids and their aftermath are studied. These conditions are developed by application of classical granular mechanics stability analysis to the asteroid environment. As part of our study we determine how slopes evolve across the surface of these bodies as a function of spin rate, the dynamical fate of material that exceeds the angle of repose, and an analysis of how the shape of the body may be modified based on these results. We find specific characteristics for body surfaces and shapes when spun near the surface disruption limit and develop what their observable implications are. The small, oblate and rapidly spinning asteroids such as 1999 KW4 Alpha and 2008 EV5 exhibit some of these observable traits. The detailed mechanisms outlined here can also provide insight and constraints on the recently observed active asteroids such as P/2013 P5, and the creation of asteroidal meteor streams.

  5. Two new basaltic asteroids in the Outer Main Belt

    CERN Document Server

    Duffard, R

    2007-01-01

    The identification of other basaltic objects in the asteroid belt is mandatory to explain the diversity in the collection of basaltic meteorites. This diversity requires more than one differentiated parent body, a fact that is consistent with the diversity of differentiated parent bodies implied by the iron meteorites. Based on a list of previously identified candidate basaltic (V-type) asteroids, two asteroids in the outer main belt, (7472) Kumakiri and (10537) 1991 RY16, were spectroscopically observed during an observational run in Calar Alto Observatory, Spain. We confirm the V-type character of these two asteroids that, together with (1459) Magnya, become the only known traces of basaltic found in the outer main belt up to now. We also demonstrate that the searching for candidate V-type asteroids using a photometric survey, like the Sloan Digital Sky Survey, produces reliable results.

  6. 5m Main Belt Asteroid Population Estimation Using Vesta Imagery

    Science.gov (United States)

    Rynders, Michael; Trilling, David E.

    2016-10-01

    The Main Belt is the largest source of Near-Earth asteroids, but objects 2 pixels in diameter that were counted in a 33km 2 region to give a crater density. By knowing the crater density and making some reasonable assumptions about the orbital distribution of asteroids and the age of Vesta's surface, an estimate of the population of small asteroids in the inner main belt was made. It was found that the inner region of the main asteroid belt contains approximately 20 billion asteroids larger than 5 m. These results agree well with the measured inner Main Belt Size distribution derived by the Wide-field Infrared Survey Explorer, WISE (Masiero et al. 2011).

  7. Mining the CFHT Legacy Survey for known Near Earth Asteroids

    CERN Document Server

    Vaduvescu, O; Birlan, M; Toma, R; Badea, M; Dumitru, D; Opriseanu, C; Vidican, D; 10.1002/asna.201011550

    2011-01-01

    The Canada-France-Hawaii Legacy Survey (CFHTLS) comprising about 25 000 MegaCam images was data mined to search for serendipitous encounters of known Near Earth Asteroids (NEAs) and Potentially Hazardous Asteroids (PHAs). A total of 143 asteroids (109 NEAs and 34 PHAs) were found on 508 candidate images which were field corrected and measured carefully, and their astrometry was reported to Minor Planet Centre. Both recoveries and precoveries (apparitions before discovery) were reported, including data for 27 precovered asteroids (20 NEAs and 7 PHAs) and 116 recovered asteroids (89 NEAs and 27 PHAs). Our data prolonged arcs for 41 orbits at first or last opposition, refined 35 orbits by fitting data taken at one new opposition, recovered 6 NEAs at their second opposition and allowed us to ameliorate most orbits and their Minimal Orbital Intersection Distance (MOID), an important parameter to monitor for potential Earth impact hazard in the future.

  8. The Asteroid Catalog Using AKARI IRC Slow-Scan Observations

    CERN Document Server

    Hasegawa, Sunao; Kuroda, Daisuke; Takita, Satoshi; Usui, Fumihiko

    2012-01-01

    We present an asteroidal catalog from the mid-infrared wavelength region using the slow-scan observation mode obtained by the Infrared Camera (IRC) on-board the Japanese infrared satellite AKARI. An archive of IRC slow-scan observations comprising about 1000 images was used to search for serendipitous encounters of known asteroids. We have determined the geometric albedos and diameters for 88 main-belt asteroids, including two asteroids in the Hilda region, and compared these, where possible, with previously published values. Approximately one-third of the acquired data reflects new asteroidal information. Some bodies classified as C or D-type with high albedo were also identified in the catalog.

  9. Scaling forces to asteroid surfaces: The role of cohesion

    CERN Document Server

    Scheeres, D J; Sanchez, P; Swift, M

    2010-01-01

    The scaling of physical forces to the extremely low ambient gravitational acceleration regimes found on the surfaces of small asteroids is performed. Resulting from this, it is found that van der Waals cohesive forces between regolith grains on asteroid surfaces should be a dominant force and compete with particle weights and be greater, in general, than electrostatic and solar radiation pressure forces. Based on this scaling, we interpret previous experiments performed on cohesive powders in the terrestrial environment as being relevant for the understanding of processes on asteroid surfaces. The implications of these terrestrial experiments for interpreting observations of asteroid surfaces and macro-porosity are considered, and yield interpretations that differ from previously assumed processes for these environments. Based on this understanding, we propose a new model for the end state of small, rapidly rotating asteroids which allows them to be comprised of relatively fine regolith grains held together b...

  10. New active asteroid 313P/Gibbs

    Energy Technology Data Exchange (ETDEWEB)

    Jewitt, David; Hui, Man-To; Li, Jing [Department of Earth, Planetary and Space Sciences, UCLA, 595 Charles Young Drive East, Los Angeles, CA 90095-1567 (United States); Agarwal, Jessica [Max Planck Institute for Solar System Research, Max-Planck-Str. 2, D-37191 Katlenburg-Lindau (Germany); Peixinho, Nuno [Unidad de Astronomía, Fac. de Ciencias Básicas, Universidad de Antofagasta, Avda. U. de Antofagasta 02800, Antofagasta (Chile); Weaver, Harold [The Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, Maryland, MD 20723 (United States); Mutchler, Max [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Larson, Stephen, E-mail: jewitt@ucla.edu [Lunar and Planetary Laboratory, University of Arizona, 1629 E. University Blvd. Tucson AZ 85721-0092 (United States)

    2015-02-01

    We present initial observations of the newly discovered active asteroid 313P/Gibbs (formerly P/2014 S4), taken to characterize its nucleus and comet-like activity. The central object has a radius ∼0.5 km (geometric albedo 0.05 assumed). We find no evidence for secondary nuclei and set (with qualifications) an upper limit to the radii of such objects near 20 m, assuming the same albedo. Both aperture photometry and a morphological analysis of the ejected dust show that mass-loss is continuous at rates ∼0.2–0.4 kg s{sup −1}, inconsistent with an impact origin. Large dust particles, with radii ∼50–100 μm, dominate the optical appearance. At 2.4 AU from the Sun, the surface equilibrium temperatures are too low for thermal or desiccation stresses to be responsible for the ejection of dust. No gas is spectroscopically detected (limiting the gas mass-loss rate to <1.8 kg s{sup −1}). However, the protracted emission of dust seen in our data and the detection of another episode of dust release near perihelion, in archival observations from 2003, are highly suggestive of an origin by the sublimation of ice. Coincidentally, the orbit of 313P/Gibbs is similar to those of several active asteroids independently suspected to be ice sublimators, including P/2012 T1, 238P/Read, and 133P/Elst–Pizarro, suggesting that ice is abundant in the outer asteroid belt.

  11. The Micro-mechanics of Asteroid Dust

    Science.gov (United States)

    Sanchez Lana, Diego Paul; Scheeres, Daniel J.

    2016-10-01

    Current understanding is that small asteroids in the Solar System are gravitational aggregates that are held together by gravitational, cohesive and adhesive forces. Though the mechanics of how gravitational forces work is very well understood, the same cannot be said about the other two.In our earlier research we used a Discrete-Element-Method simulation code to calculate the tensile strength of an assemblage of cohesive particles and found that the main geometrical factor controlling bulk strength was the average size of the particles (Sanchez and Scheeres 2014, MAPS). Specifically, the smaller the average size, the greater the tensile strength as r^-1, as though the magnitude of the van der Waals force applied decrease with the radius of the grains (r), the number of contacts per unit area increases with r^-2. This dependency has been corroborated by some observational evidence of the global strength of granular asteroids; however, our simulations were carried out with spherical particles and therefore in these simulations it is impossible to consider more than one contact per pair of particles. Other parameters such as different chemical composition and wider size distribution of the grains, changes in porosity and number of contacts per particle (coordination number) were not taken into direct account either. The study of each one of these parameters is of interest, and our research has started to explore the effect of these on the net cohesive force found in an asteroid's regolith and interior.Our initial study will simulate the effect of a wider size distribution in the granular material, comparing this with theoretical predictions. This parameter can cause a change in porosity and coordination number of the grains. This will have a measurable effect in the tensile strength of the aggregate and will provide a first look into the strength of a more realistic cohesive granular media. The results of this research will be shown at the conference.

  12. Microspine Gripping Mechanism for Asteroid Capture

    Science.gov (United States)

    Merriam, Ezekiel G.; Berg, Andrew B.; Willig, Andrew; Parness, Aaron; Frey, Tim; Howell, Larry L.

    2016-01-01

    This paper details the development and early testing of a compliant suspension for a microspine gripper device for asteroid capture or micro-gravity percussive drilling. The microspine gripper architecture is reviewed, and a proposed microspine suspension design is presented and discussed. Prototyping methods are discussed, as well as testing methods and results. A path forward is identified from the results of the testing completed thus far. Key findings include: the microspine concept has been established as a valid architecture and the compliant suspension exhibits the desired stiffness characteristics for good gripping behavior. These developments will aid in developing the capability to grasp irregularly shaped boulders in micro-gravity.

  13. Space Weathering Trends Among Carbonaceous Asteroids

    CERN Document Server

    Kaluna, Heather M; Meech, Karen J

    2015-01-01

    We present visible spectroscopic and albedo data of the 2.3 Gyr old Themis family and the 15 km) and small (< 15 km) Themis members suggest these phyllosilicate feature and albedo trends result from regolith variations as a function of diameter. Observations of the Beagle asteroids show a small, but notable fraction of members with phyllosilicate features. The presence of phyllosilicates and the dynamical association of the main-belt comet 133P/Elst-Pizarro with the Beagle family imply the Beagle parent body was a heterogenous mixture of ice and aqueously altered minerals.

  14. NASA's Near Earth Asteroid Scout Mission

    Science.gov (United States)

    Johnson, Les; McNutt, Leslie; Castillo-Rogez, Julie

    2017-01-01

    NASA is developing solar sail propulsion for a near-term Near Earth Asteroid (NEA) reconnaissance mission and laying the groundwork for their future use in deep space science and exploration missions. The NEA Scout mission, funded by NASA's Advanced Exploration Systems Program and managed by NASA MSFC, will use the sail as primary propulsion allowing it to survey and image one or more NEA's of interest for possible future human exploration. NEA Scout uses a 6U cubesat (to be provided by NASA's Jet Propulsion Laboratory), an 86 m2 solar sail and will weigh less than 14 kilograms. The solar sail for NEA Scout will be based on the technology developed and flown by the NASA NanoSail-D and The Planetary Society's Lightsail-A. Four 7 m stainless steel booms wrapped on two spools (two overlapping booms per spool) will be motor deployed and pull the sail from its stowed volume. The sail material is an aluminized polyimide approximately 3 microns thick. NEA Scout will launch on the Space Launch System (SLS) first mission in 2018 and deploy from the SLS after the Orion spacecraft is separated from the SLS upper stage. The NEA Scout spacecraft will stabilize its orientation after ejection using an onboard cold-gas thruster system. The same system provides the vehicle Delta-V sufficient for a lunar flyby. After its first encounter with the moon, the 86 m2 sail will deploy, and the sail characterization phase will begin. A mechanical Active Mass Translation (AMT) system, combined with the remaining ACS propellant, will be used for sail momentum management. Once the system is checked out, the spacecraft will perform a series of lunar flybys until it achieves optimum departure trajectory to the target asteroid. The spacecraft will then begin its two year-long cruise. About one month before the asteroid flyby, NEA Scout will pause to search for the target and start its approach phase using a combination of radio tracking and optical navigation. The solar sail will provide

  15. The Nearest of the Near Earth Asteroids

    Science.gov (United States)

    Kortenkamp, Stephen J.

    2014-11-01

    While the orbits of many known near-Earth objects (NEOs) may cross that of Earth, very few NEOs actually approach near to Earth itself. In fact, the majority of NEOs spend most of their orbital periods in the asteroid belt beyond Mars. However, there is a subset of NEOs on orbits which allow for repeated close-encounters with Earth. These objects are locked in a co-orbital resonance with Earth, orbiting the sun in exactly one year. This unusual one-to-one resonance causes the NEOs to appear to be orbiting Earth and gives them their name; quasi-satellites.Despite their close proximity to Earth, only recently have the first quasi-satellites of Earth been detected. These are the asteroids 2003 YN107, 2004 GU9, and 2006 FV35. We carried out N-body computer simulations of these asteroids as well as a larger theoretical population. We demonstrate that quasi-satellite asteroids always remain exceptionally close to Earth, typically just 20-60 times farther than the moon, and undergo two close-encounters with Earth each year. Furthermore, quasi-satellites that eventually escape the resonance can have extremely deep low-velocity close-encounters with Earth as they leave the resonance, some coming well inside the orbit of the moon.When weak drag forces are included in the simulations quasi-satellite objects evolve onto more Earth-like orbits and spiral closer and closer to Earth. This dramatically reduces the relative velocity and distance of closest approach between Earth and the quasi-satellite object. Under the influence of weak drag quasi-satellites objects can develop effective encounter velocities of just a few hundred meters per second, often much less. These low encounter velocities lead to a strong enhancement in Earth’s gravitationally enhanced impact cross-section compared to close-encounters of non-resonant objects with similar initial orbital elements.This research is supported by NASA grant NNX14AN23G.

  16. Period Determination of Six Main Belt Asteroids

    Science.gov (United States)

    Ferrero, Andrea

    2014-07-01

    Observations of six main-belt asteroids (MBA) produced lightcurve parameters of: 487 Venetia, P = 13.34 ± 0.01 h, A = 0.20 mag; 684 Hildburg, P = 15.89 ± 0.01 h, A = 0.22 mag; 772 Tanete, P = 8.629 ± 0.001 h, A = 0.18 mag.; 1181 Lilith, P = 15.04 ± 0.01 h, A = 0.11 mag.; 1246 Chaka, P = 25.44 ± 0.01 h, A = 0.25 mag.; and 2834 Christy Carol, P = 12.79 ± 0.01 h, A = 0.39 mag.

  17. Impulsive orbit control for spacecraft around asteroid

    Institute of Scientific and Technical Information of China (English)

    崔祜涛; 崔平远; 栾恩杰

    2003-01-01

    An impulse feedback control law to change the mean orbit elements of spacecraft around asteroid is presented. First, the mean orbit elements are transferred to the osculating orbit elements at the burning time.Then, the feedback control law based on Gauss' s perturbation equations of motion is given. And the impulse control for targeting from the higher circulation orbit to the specified periapsis is developed. Finally, the numerical simulation is performed and the simulation results show that the presented impulse control law is effective.

  18. Formation and Dynamical Evolution of the Asteroid Belt

    Science.gov (United States)

    Bottke, William F.

    2015-08-01

    Asteroids are critical to our desire to unravel the origin of the Solar System because they supply unique, relatively pristine snapshots of the environment in which the Earth formed and evolved. This is due to the fact that, although the asteroids and Earth have followed very different evolutionary pathways, they all formed from the same set of physical processes and share a common ancestry. The asteroid belt presents a particular challenge to understanding terrestrial planet formation because of its small mass. Models of the protoplanetary disk suggest the region between 2-3 AU should contain roughly 3 Earth masses, while less than 0.001 of an Earth mass is actually found there.A long-standing explanation for the asteroid belt's small mass is that it is due to the gravitational influence of Jupiter and Saturn. Some have suggested protoplanets grew there before they were dynamically removed from the asteroid belt by resonances with the gas giants. This left the asteroid belt dynamically excited (which is observed) and heavily depleted in mass. More recently, however, detailed models have shown that this process produces an asteroid belt that is inconsistent with observations.Two recent models propose new ways to match asteroid belt constraints. The first, the so-called ‘Grand Tack’ scenario, uses the results of hydrodynamic simulations to show that Jupiter (and Saturn) migrated both inward and outward across the asteroid belt while interacting with the protoplanetary gas disk. The Grand Tack not only reproduces the mass and mixture of spectral types in the asteroid belt, but it also truncates the planetesimal disk from which the terrestrial planets form, potentially explaining why Mars is less massive than Earth. In a second scenario, planetesimals that form directly from cm- to meter-sized objects, known as “pebbles”, are rapidly converted to 100 to 1000 km asteroid-like object that subsequently grow by accreting even more pebbles. Pebble accretion models

  19. Galileo photometry of asteroid 243 Ida

    Science.gov (United States)

    Helfenstein, P.; Veverka, J.; Thomas, P.C.; Simonelli, D.P.; Klaasen, K.; Johnson, T.V.; Fanale, F.; Granahan, J.; McEwen, A.S.; Belton, M.; Chapman, C.

    1996-01-01

    Galileo imaging observations over phase angles 19.5?? to 109.8?? are combined with near-opposition Earth-based data to derive the photometric properties of Ida. To first order these properties are uniform over the surface and well modeled at ?? = 0.55 ??m by Hapke parameters ????0 = 0.22, h = 0.020, B0 = 1.5, g = -0.33, and ?? = 18?? with corresponding geometric albedo p = 0.21??0.030.01 and Bond albedo AB = 0.081??0.0170.008. Ida's photometric properties are more similar to those of "average S-asteroids" (P. Helfenstein and J. Veverka 1989, Asteroids II, Univ. of Arizona Press, Tucson) than are those of 951 Gaspra. Two primary color units are identified on Ida: Terrain A exhibits a spectrum with relatively shallower 1-??m absorption and a relatively steeper red spectral slope than average Ida, while Terrain B has a deeper 1-??m absorption and a less steep red slope. The average photometric properties of Ida and Terrain A are similar while those of Terrain B differ mostly in having a slightly higher value of ????0 (0.22 versus 0.21), suggesting that Terrain B consists of slightly brighter, more transparent regolith particles. Galileo observations of Ida's satellite Dactyl over phase angles 19.5?? to 47.6?? suggest photometric characteristics similar to those of Ida, the major difference being Dactyl's slightly lower albedo (0.20 compared to 0.21). ?? 1990 Academic Press, Inc.

  20. Can Asteroid Airbursts Cause Dangerous Tsunami?.

    Energy Technology Data Exchange (ETDEWEB)

    Boslough, Mark B. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-10-01

    I have performed a series of high-resolution hydrocode simulations to generate “source functions” for tsunami simulations as part of a proof-of-principle effort to determine whether or not the downward momentum from an asteroid airburst can couple energy into a dangerous tsunami in deep water. My new CTH simulations show enhanced momentum multiplication relative to a nuclear explosion of the same yield. Extensive sensitivity and convergence analyses demonstrate that results are robust and repeatable for simulations with sufficiently high resolution using adaptive mesh refinement. I have provided surface overpressure and wind velocity fields to tsunami modelers to use as time-dependent boundary conditions and to test the hypothesis that this mechanism can enhance the strength of the resulting shallow-water wave. The enhanced momentum result suggests that coupling from an over-water plume-forming airburst could be a more efficient tsunami source mechanism than a collapsing impact cavity or direct air blast alone, but not necessarily due to the originally-proposed mechanism. This result has significant implications for asteroid impact risk assessment and airburst-generated tsunami will be the focus of a NASA-sponsored workshop at the Ames Research Center next summer, with follow-on funding expected.

  1. The Albedo Distribution of Near Earth Asteroids

    CERN Document Server

    Wright, Edward L; Masiero, Joseph; Grav, Tommy; Bauer, James

    2016-01-01

    The cryogenic WISE mission in 2010 was extremely sensitive to asteroids and not biased against detecting dark objects. The albedos of 428 Near Earth Asteroids (NEAs) observed by WISE during its fully cryogenic mission can be fit quite well by a 3 parameter function that is the sum of two Rayleigh distributions. The Rayleigh distribution is zero for negative values, and follows $f(x) = x \\exp[-x^2/(2\\sigma^2)]/\\sigma^2$ for positive x. The peak value is at x=\\sigma, so the position and width are tied together. The three parameters are the fraction of the objects in the dark population, the position of the dark peak, and the position of the brighter peak. We find that 25.3% of the NEAs observed by WISE are in a very dark population peaking at $p_V = 0.03$, while the other 74.7% of the NEAs seen by WISE are in a moderately dark population peaking at $p_V = 0.168$. A consequence of this bimodal distribution is that the Congressional mandate to find 90% of all NEAs larger than 140 m diameter cannot be satisfied by...

  2. Asteroid Regolith Simulants: Development, Characteristics, and Testing

    Science.gov (United States)

    Britt, D. T.

    2015-12-01

    As part of a NASA Small Business Innovation Research (SBIR) award to the University of Central Florida and Deep Space Industries, we are developing a family of asteroid regolith simulants based on meteorite mineralogies but using terrestrial materials, to support NASAs exploration goals for asteroids. We are planning on developing five types of simulant based on the following meteorite types: CI-carbonaceous chondrite, CM-carbonaceous chondrite, Tagish Lake, L-ordinary chondrite, and iron. To the greatest extent reasonable (based on input costs and health/safety) we will duplicate the mineralogy, chemistry, oxidation state, hydration state, and particle size distribution found in regolith meteorites of each type. The major limitations on the fidelity of simulant will be health and safety issues for the users of the simulants. For example, much of the organic component of volatile-rich carbonaceous chondrites are in the form of Polycyclic Aromatic Hydrocarbons (PAHs). These are essentially combustion residues, possibly of complex regolith processing, with more carbon atoms than hydrogen. However, many PAHs are toxic, carcinogenic, and/or mutagenic. Several are banned in the European Union and California. This sort of material would endanger users, be impossible to distribute, and not make a useable regolith simulant. There are several reasonable, no-toxic alternatives to PAHs. We will report on the status of simulant development and the progress of our validation experiments.

  3. Self-organizing control strategy for asteroid intelligent detection swarm based on attraction and repulsion

    Science.gov (United States)

    An, Meiyan; Wang, Zhaokui; Zhang, Yulin

    2017-01-01

    The self-organizing control strategy for asteroid intelligent detection swarm, which is considered as a space application instance of intelligent swarm, is developed. The leader-follower model for the asteroid intelligent detection swarm is established, and the further analysis is conducted for massive asteroid and small asteroid. For a massive asteroid, the leader spacecraft flies under the gravity field of the asteroid. For a small asteroid, the asteroid gravity is negligible, and a trajectory planning method is proposed based on elliptic cavity virtual potential field. The self-organizing control strategy for the follower spacecraft is developed based on a mechanism of velocity planning and velocity tracking. The simulation results show that the self-organizing control strategy is valid for both massive asteroid and small asteroid, and the exploration swarm forms a stable configuration.

  4. Asteroid detection using a single multi-wavelength CCD scan

    Science.gov (United States)

    Melton, Jonathan

    2016-09-01

    Asteroid detection is a topic of great interest due to the possibility of diverting possibly dangerous asteroids or mining potentially lucrative ones. Currently, asteroid detection is generally performed by taking multiple images of the same patch of sky separated by 10-15 minutes, then subtracting the images to find movement. However, this is time consuming because of the need to revisit the same area multiple times per night. This paper describes an algorithm that can detect asteroids using a single CCD camera scan, thus cutting down on the time and cost of an asteroid survey. The algorithm is based on the fact that some telescopes scan the sky at multiple wavelengths with a small time separation between the wavelength components. As a result, an object moving with sufficient speed will appear in different places in different wavelength components of the same image. Using image processing techniques we detect the centroids of points of light in the first component and compare these positions to the centroids in the other components using a nearest neighbor algorithm. The algorithm was used on a test set of 49 images obtained from the Sloan telescope in New Mexico and found 100% of known asteroids with only 3 false positives. This algorithm has the advantage of decreasing the amount of time required to perform an asteroid scan, thus allowing more sky to be scanned in the same amount of time or freeing a telescope for other pursuits.

  5. Multiple-hopping trajectories near a rotating asteroid

    Science.gov (United States)

    Shen, Hong-Xin; Zhang, Tian-Jiao; Li, Zhao; Li, Heng-Nian

    2017-03-01

    We present a study of the transfer orbits connecting landing points of irregular-shaped asteroids. The landing points do not touch the surface of the asteroids and are chosen several meters above the surface. The ant colony optimization technique is used to calculate the multiple-hopping trajectories near an arbitrary irregular asteroid. This new method has three steps which are as follows: (1) the search of the maximal clique of candidate target landing points; (2) leg optimization connecting all landing point pairs; and (3) the hopping sequence optimization. In particular this method is applied to asteroids 433 Eros and 216 Kleopatra. We impose a critical constraint on the target landing points to allow for extensive exploration of the asteroid: the relative distance between all the arrived target positions should be larger than a minimum allowed value. Ant colony optimization is applied to find the set and sequence of targets, and the differential evolution algorithm is used to solve for the hopping orbits. The minimum-velocity increment tours of hopping trajectories connecting all the landing positions are obtained by ant colony optimization. The results from different size asteroids indicate that the cost of the minimum velocity-increment tour depends on the size of the asteroids.

  6. THE ORIGIN OF ASTEROID 162173 (1999 JU{sub 3})

    Energy Technology Data Exchange (ETDEWEB)

    Campins, Humberto [Physics Department, University of Central Florida, P.O. Box 162385, Orlando, FL 32816-2385 (United States); De Leon, Julia [Department of Edaphology and Geology, University of La Laguna, E-38071 Tenerife (Spain); Morbidelli, Alessandro; Gayon-Markt, Julie; Delbo, Marco; Michel, Patrick [Observatoire de la Cote d' Azur, Universite de Nice Sophia Antipolis (UNS), CNRS UMR7293, F-06108 Nice Cedex 2 (France); Licandro, Javier [Instituto de Astrofisica de Canarias (IAC), C/Via Lactea s/n, E-38205 La Laguna (Spain)

    2013-08-01

    Near-Earth asteroid (162173) 1999 JU{sub 3} (henceforth JU{sub 3}) is a potentially hazardous asteroid and the target of the Japanese Aerospace Exploration Agency's Hayabusa-2 sample return mission. JU{sub 3} is also a backup target for two other sample return missions: NASA's OSIRIS-REx and the European Space Agency's Marco Polo-R. We use dynamical information to identify an inner-belt, low-inclination origin through the {nu}{sub 6} resonance, more specifically, the region with 2.15 AU < a < 2.5 AU and i < 8 Degree-Sign . The geometric albedo of JU{sub 3} is 0.07 {+-} 0.01, and this inner-belt region contains four well-defined low-albedo asteroid families (Clarissa, Erigone, Polana, and Sulamitis), plus a recently identified background population of low-albedo asteroids outside these families. Only two of these five groups, the background and the Polana family, deliver JU{sub 3}-sized asteroids to the {nu}{sub 6} resonance, and the background delivers significantly more JU{sub 3}-sized asteroids. The available spectral evidence is also diagnostic; the visible and near-infrared spectra of JU{sub 3} indicate it is a C-type asteroid, which is compatible with members of the background, but not with the Polana family because it contains primarily B-type asteroids. Hence, this background population of low-albedo asteroids is the most likely source of JU{sub 3}.

  7. Granular convection and its application to asteroidal resurfacing timescale

    Science.gov (United States)

    Yamada, Tomoya; Ando, Kosuke; Morota, Tomokatsu; Katsuragi, Hiroaki

    2016-04-01

    A model for the asteroid resurfacing resulting from regolith convection is built to estimate its timescale. The regolith convection by impact-induced global seismic shaking could be a possible reason for regolith migration and resultant segregated terrain which were found on the asteroids Itokawa [1]. Some recent studies [2, 3] experimentally investigated the convective velocity of the vibrated granular bed to discuss the feasibility of regolith convection under the microgravity condition such as small asteroids. These studies found that the granular convective velocity is almost proportional to the gravitational acceleration [2, 3]. Namely, the granular (regolith) convective velocity would be very low under the microgravity condition. Therefore, the timescale of resurfacing by regolith convection would become very long. In order to examine the feasibility of the resurfacing by regolith convection on asteroids, its timescale have to be compared with the surface age or the lifetime of asteroids. In this study, we aim at developing a model of asteroid resurfacing process induced by regolith convection. The model allows us to estimate the resurfacing timescale for various-sized asteroids covered with regolith. In the model, regolith convection is driven by the impact-induced global seismic shaking. The model consists of three phases, (i) Impact phase: An impactor intermittently collides with a target asteroid [4], (ii) Vibration phase: The collision results in a global seismic shaking [5], (iii) Convection phase: The global seismic shaking induces the regolith convection on the asteroid [3]. For the feasibility assessment of the resurfacing process driven by regolith convection, we estimate the regolith-convection-based resurfacing timescale T as a function of the size of a target asteroid Da. According to the estimated result, the resurfacing time scale is 40 Myr for the Itokawa-sized asteroid, and this value is shorter than the mean collisional lifetime of Itokawa

  8. A Spectroscopically Unique Main Belt Asteroid: 10537 (1991 RY16)

    CERN Document Server

    Moskovitz, Nicholas A; Jedicke, Robert; Willman, Mark; Haghighipour, Nader; Bus, Schelte J; Gaidos, Eric

    2008-01-01

    We present visible and near-infrared reflectance spectra and interpreted surface mineralogy for asteroid 10537 (1991 RY16). The spectrum of this object is without precedent amongst the Main Belt asteroids. A unique absorption band centered at 0.63 microns could be attributed to one of several mineralogies. Pronounced 1- and 2-micron absorption bands suggest that the composition of 10537 is a mixture of pyroxenes and olivine and that it originated from a parent body that was partially or fully differentiated. The closest available analog is the large Main Belt asteroid 349 Dembowska but 10537 may be an isolated fragment from a completely eroded parent body.

  9. NEOWISE REACTIVATION MISSION YEAR ONE: PRELIMINARY ASTEROID DIAMETERS AND ALBEDOS

    Energy Technology Data Exchange (ETDEWEB)

    Nugent, C. R.; Cutri, R. M. [Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125 (United States); Mainzer, A.; Masiero, J.; Bauer, J.; Kramer, E.; Sonnett, S.; Stevenson, R. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Grav, T. [Planetary Science Institute, Tucson, AZ (United States); Wright, E. L., E-mail: cnugent@ipac.caltech.edu [Department of Physics and Astronomy, University of California, Los Angeles, CA 90095 (United States)

    2015-12-01

    We present preliminary diameters and albedos for 7956 asteroids detected in the first year of the NEOWISE Reactivation mission. Of those, 201 are near-Earth asteroids and 7755 are Main Belt or Mars-crossing asteroids. 17% of these objects have not been previously characterized using the Near-Earth Object Wide-field Infrared Survey Explorer, or “NEOWISE” thermal measurements. Diameters are determined to an accuracy of ∼20% or better. If good-quality H magnitudes are available, albedos can be determined to within ∼40% or better.

  10. Photometry and shape modeling of Mars crosser asteroid (1011 Laodamia

    Directory of Open Access Journals (Sweden)

    Apostolovska G.

    2014-01-01

    Full Text Available An analysis of photometric observations of Mars crosser asteroid 1011 Laodamia conducted at Bulgarian National Astronomical Observatory Rozhen over a twelve year interval (2002, 2003, 2004, 2006, 2007, 2008, 2011, 2012 and 2013 is made. Based on the obtained lightcurves the spin vector, sense of rotation, and preliminary shape model of (1011 Laodamia have been determined using the lightcurve inversion method. The aim of this investigation is to increase the set of asteroids with known spin and shape parameters and to contribute in improving the model in combination with other techniques and sparse data produced by photometric asteroid surveys such as Pan-STARRS or GAIA.

  11. Asteroid Sufaces/Regoliths Deduced by Remote Sensing

    Science.gov (United States)

    Price, S.

    Resolved imagery on a small number of asteroids provides information about the size, density and surface relief from which inferences may be made regarding their regoliths; Eros Eros is the best studied asteroid in this regard However, remote sensing is necessary to deduce properties for the large majority of objects. These techniques include: spectroscopy and multi-spectral band photometry, which provide clues as to the chemical composition of the surface, infrared (plus visible) radiometry, from which physical bulk and surface properties may be inferred through the derived albedo and thermal inertia, and radar, which permits one to deduce the near surface bulk density. This article reviews what these techniques have revealed about the surface characteristics of asteroids. Asteroids have been classified by the broad emissive properties of the surface as indicated by filter band photometry. Recently, observations from large scale surveys - 2MASS (Denis to a lesser extent) and the Sloan Digital Sky Survey - provided taxonomic classifications for thousands of asteroids. The mineralogy is more secure at higher spectral resolution. Silicates on the surface of asteroids have been inferred from IRAS, ISO and Kuiper Airborne infrared spectra. Infrared radiometry has been used to derive the albedos and diameters of ~2300 asteroids observed by IRAS and MSX. The simplified Standard Thermal Model (STM) works well for main belt asteroids. The model assumes that the asteroid does not rotate and is in instantaneous thermal equilibrium between absorbed sunlight and emitted radiation. Empirical factors for flux enhancement (beaming) and phase function are adopted. There is a dichotomy between large and small asteroids in this database. About 20% of the asteroids with diameters inertia, rotation rate, orientation of the rotation pole, surface roughness and degree of cratering. A complex model is required to account for all the variables. Such a model was developed using full

  12. Redox effects in ordinary chondrites and implications for asteroid spectrophotometry

    Science.gov (United States)

    Mcsween, Harry Y., Jr.

    1992-01-01

    The sensitivity of reflectance spectra to mean ferrous iron content and olivine and pyroxene proportion enhancements in the course of metamorphic oxidation is presently used to examine whether metamorphically-induced ranges in mineralogy, and corresponding spectral parameters, may explain the observed variations in S-asteroid rotational spectra. The predicted spectral variations within any one chondrite class are, however, insufficient to account for S-asteroid rotational spectra, and predicted spectral-range slopes have a sign opposite to the rotational measurements. Metamorphic oxidation is found unable to account for S-asteroid rotational spectra.

  13. Deep space flight of Hayabusa asteroid explorer

    Science.gov (United States)

    Kuninaka, Hitoshi; Kawaguchi, Jun'ichiro

    2008-04-01

    The Hayabusa spacecraft rendezvoused with the asteroid Itokawa in 2005 after the powered flight in the deep space by the μ10 cathode-less electron cyclotron resonance ion engines. Though the spacecraft was seriously damaged after the successful soft-landing and lift-off, the xenon cold gas jets from the ion engines rescued it. New attitude stabilization method using a single reaction wheel, the ion beam jets, and the photon pressure was established and enabled the homeward journey from April 2007 aiming the Earth return on 2010. The total accumulated operational time of the ion engines reaches 31,400 hours at the end of 2007. One of four thrusters achieved 13,400-hour space operation.

  14. The Near Earth Asteroid Medical Conditions List

    Science.gov (United States)

    Barr, Yael R.; Watkins, S. D.

    2011-01-01

    Purpose: The Exploration Medical Capability (ExMC) element is one of six elements within NASA s Human Research Program (HRP) and is responsible for addressing the risk of "the inability to adequately recognize or treat an ill or injured crewmember" for exploration-class missions. The Near Earth Asteroid (NEA) Medical Conditions List, constructed by ExMC, is the first step in addressing the above-mentioned risk for the 13-month long NEA mission. The NEA mission is being designed by NASA's Human Space Flight Architecture Team (HAT). The purpose of the conditions list is to serve as an evidence-based foundation for determining which medical conditions could affect a crewmember during the NEA mission, which of those conditions would be of concern and require treatment, and for which conditions a gap in knowledge or technology development exists. This information is used to focus research efforts and technology development to ensure that the appropriate medical capabilities are available for exploration-class missions. Scope and Approach: The NEA Medical Conditions List is part of a broader Space Medicine Exploration Medical Conditions List (SMEMCL), which incorporates various exploration-class design reference missions (DRMs). The conditions list contains 85 medical conditions which could occur during space flight and which are derived from several sources: Long-Term Surveillance of Astronaut Health (LSAH) in-flight occurrence data, The Space Shuttle (STS) Medical Checklist, The International Space Station (ISS) Medical Checklist, and subject matter expert opinion. Each medical condition listed has been assigned a clinical priority and a clinical priority rationale based on incidence, consequence, and mitigation capability. Implementation: The conditions list is a "living document" and as such, new conditions can be added to the list, and the priority of conditions on the list can be adjusted as the DRM changes, and as screening, diagnosis, or treatment capabilities

  15. An ancient core dynamo in asteroid Vesta.

    Science.gov (United States)

    Fu, Roger R; Weiss, Benjamin P; Shuster, David L; Gattacceca, Jérôme; Grove, Timothy L; Suavet, Clément; Lima, Eduardo A; Li, Luyao; Kuan, Aaron T

    2012-10-12

    The asteroid Vesta is the smallest known planetary body that has experienced large-scale igneous differentiation. However, it has been previously uncertain whether Vesta and similarly sized planetesimals formed advecting metallic cores and dynamo magnetic fields. Here we show that remanent magnetization in the eucrite meteorite Allan Hills A81001 formed during cooling on Vesta 3.69 billion years ago in a surface magnetic field of at least 2 microteslas. This field most likely originated from crustal remanence produced by an earlier dynamo, suggesting that Vesta formed an advecting liquid metallic core. Furthermore, the inferred present-day crustal fields can account for the lack of solar wind ion-generated space weathering effects on Vesta.

  16. Detecting stars, galaxies, and asteroids with Gaia

    CERN Document Server

    de Bruijne, J H J; Azaz, S; Krone-Martins, A; Prod'homme, T; Hestroffer, D

    2015-01-01

    (Abridged) Gaia aims to make a 3-dimensional map of 1,000 million stars in our Milky Way to unravel its kinematical, dynamical, and chemical structure and evolution. Gaia's on-board detection software discriminates stars from spurious objects like cosmic rays and Solar protons. For this, parametrised point-spread-function-shape criteria are used. This study aims to provide an optimum set of parameters for these filters. We developed an emulation of the on-board detection software, which has 20 free, so-called rejection parameters which govern the boundaries between stars on the one hand and sharp or extended events on the other hand. We evaluate the detection and rejection performance of the algorithm using catalogues of simulated single stars, double stars, cosmic rays, Solar protons, unresolved galaxies, and asteroids. We optimised the rejection parameters, improving - with respect to the functional baseline - the detection performance of single and double stars, while, at the same time, improving the rejec...

  17. Serendipitous asteroid observations by OSIRIS/Rosetta

    Science.gov (United States)

    Carry, B.; Berthier, J.; Vachier, F.; Küppers, M.

    2012-09-01

    In recent years, many efforts have been undertaken to extract the astrometry, photometry, and colors of Solar System Small Bodies from large surveys and widefield camera, such as the SDSS Moving Object Catalog [2] or EuroNear [3]. Since 2006, the IMCCE provides a service, called SkyBoT [1], that list all the Solar System Objects in a given field of view for a given epoch. Such a tool is of high interest for any data mining purpose of large archives. We will present an extension of SkyBoT from ground-based to space-based geometries. As a demonstration, we will present our search for serendipitously observed asteroids in the data archive of the OSIRIS instrument on-board the ESA Rosetta mission.

  18. Systematic ranging and late warning asteroid impacts

    CERN Document Server

    Farnocchia, D; Micheli, M

    2015-01-01

    We describe systematic ranging, an orbit determination technique especially suitable to assess the near-term Earth impact hazard posed by newly discovered asteroids. For these late warning cases, the time interval covered by the observations is generally short, perhaps a few hours or even less, which leads to severe degeneracies in the orbit estimation process. The systematic ranging approach gets around these degeneracies by performing a raster scan in the poorly-constrained space of topocentric range and range rate, while the plane of sky position and motion are directly tied to the recorded observations. This scan allows us to identify regions corresponding to collision solutions, as well as potential impact times and locations. From the probability distribution of the observation errors, we obtain a probability distribution in the orbital space and then estimate the probability of an Earth impact. We show how this technique is effective for a number of examples, including 2008 TC3 and 2014 AA, the only tw...

  19. GRASPING THE NATURE OF POTENTIALLY HAZARDOUS ASTEROIDS

    Energy Technology Data Exchange (ETDEWEB)

    Perna, D.; Barucci, M. A.; Fornasier, S.; Deshapriya, J. D. P. [LESIA—Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC Univ. Paris 06, Univ. Paris Diderot, Sorbonne Paris Cité, 5 place Jules Janssen, F-92195 Meudon (France); Dotto, E.; Ieva, S.; Epifani, E. Mazzotta [INAF—Osservatorio Astronomico di Roma, Via Frascati 33, I-00040 Monte Porzio Catone (Roma) (Italy); Bernardi, F. [SpaceDyS, via Mario Giuntini 63, I-56023 Cascina (Pisa) (Italy); Luise, F. De [INAF—Osservatorio Astronomico di Teramo, via Mentore Maggini snd, I-64100 Teramo (Italy); Perozzi, E. [Deimos Space, Strada Buchesti 75-77, Bucharest (Romania); Rossi, A. [IFAC—CNR, via Madonna del Piano 10, I-50019 Sesto Fiorentino (Firenze) (Italy); Micheli, M., E-mail: davide.perna@obspm.fr [ESA—NEOCC, ESRIN, via Galileo Galilei 64, I-00044 Frascati (Rome) (Italy)

    2016-01-15

    Through their delivery of water and organics, near-Earth objects (NEOs) played an important role in the emergence of life on our planet.  However, they also pose a hazard to the Earth, as asteroid impacts could significantly affect our civilization. Potentially hazardous asteroids (PHAs) are those that, in principle, could possibly impact the Earth within the next century, producing major damage. About 1600 PHAs are currently known, from an estimated population of 4700 ± 1450. However, a comprehensive characterization of the PHA physical properties is still missing. Here we present spectroscopic observations of 14 PHAs, which we have used to derive their taxonomy, meteorite analogs, and mineralogy. Combining our results with the literature, we investigated how PHAs are distributed as a function of their dynamical and physical properties. In general, the “carbonaceous” PHAs seem to be particularly threatening, because of their high porosity (limiting the effectiveness of the main deflection techniques that could be used in space) and low inclination and minimum orbit intersection distance (MOID) with the Earth (favoring more frequent close approaches). V-type PHAs also present low MOID values, which can produce frequent close approaches (as confirmed by the recent discovery of a limited space weathering on their surfaces). We also identified those specific objects that deserve particular attention because of their extreme rotational properties, internal strength, or possible cometary nature. For PHAs and NEOs in general, we identified a possible anti-correlation between the elongation and the rotational period, in the range of P{sub rot} ≈ 5–80 hr. This would be compatible with the behavior of gravity-dominated aggregates in rotational equilibrium. For periods ≳80–90 hr, such a trend stops, possibly under the influence of the YORP effect and collisions. However, the statistics is very low, and further observational and theoretical work is required

  20. El destino del asteroide Albert (719)

    Science.gov (United States)

    Orellana, R. B.; Melita, M. D.; Brunini, A.

    Albert is the only numbered asteroid that remains lost at present. This object has been discovered while it was making a close apporach to the Earth by Johann Palisa in the Imperial Observatory of Vienna. According to the standard procedure of the time, a number was assigned to it shortly after a preliminar orbit has been obtained and it was named after a great benefactor of Imperial Observatory, Baron Albert von Rothschild. In this work we analyze why this body could not be recovered in its subsequent approaches to the Earth. Basicaly the cause of the loss can be summarized as follows. Given the high absolute magnitude of the object it can only be observed when it is close to the Earth. But naturally, at the close approches, the uncertanty in the position in the celestial sphere is the greatest due to a parallax effect. We have estimated the uncertanty in R.A. and declination by the non-linear propagation of the initial obervational uncertanty. We have determined that, when the aparent magnitude was low enough to observe the object with the instruments available at the time, the uncertainty region exceeded noticeably the region where it was searched. Regarding its possible recovery at present, the uncertainty in its position practicaly covers the whole sky. Nevertheless, the plane of the orbit is bounded in a narrow strip for a considerable length of time, which makes its recovery posible in old plates. The causes of the loss of Albert (719) are common to all NEO's, which is distintive about it is that it was numbered after just a few obervations, while at present the standard procedure requires that the orbit should be very well established before a denomination is given. Given the almost imposibility of its systematic recovery, in the future Albert (719) might be the first asteroid whose denomination is reassigned to another object.

  1. Sparse source configurations for asteroid tomography

    Science.gov (United States)

    Pursiainen, S.; Kaasalainen, M.

    2014-04-01

    The objective of our recent research has been to develop non-invasive imaging techniques for future planetary research and mining activities involving a challenging in situ environment and tight payload limits [1]. This presentation will deal in particular with an approach in which the internal relative permittivity ∈r or the refractive index n = √ ∈r of an asteroid is to be recovered based on radio signal transmitted by a sparse set [2] of fixed or movable landers. To address important aspects of mission planning, we have analyzed different signal source configurations to find the minimal number of source positions needed for robust localization of anomalies, such as internal voids. Characteristic to this inverse problem are the large relative changes in signal speed caused by the high permittivity of typical asteroid minerals (e.g. basalt), leading to strong refractions and reflections of the signal. Finding an appropriate problemspecific signaling arrangement is an important premission goal for successful in situ measurements. This presentation will include inversion results obtained with laboratory-recorded travel time data y of the form in which n δ denotes a perturbation of a refractive index n = n δ + nbg; gi estimates the total noise due to different error sources; (ybg)i = ∫Ci nbg ds is an entry of noiseless background data ybg; and Ci is a signal path. Also simulated time-evolution data will be covered with respect to potential u satisfying the wave equation ∈rδ2/δt2+ ōδu/δt-∆u = f, where ō is a (latent) conductivity distribution and f is a source term. Special interest will be paid to inversion robustness regarding changes of the prior model and source positioning. Among other things, our analysis suggests that strongly refractive anomalies can be detected with three or four sources independently of their positioning.

  2. Radar reconnaissance of near-Earth asteroids

    Science.gov (United States)

    Ostro, Steven J.; Giorgini, Jon D.; Benner, Lance A. M.

    2007-05-01

    Radar is a uniquely powerful source of information about near-Earth asteroid (NEA) physical properties and orbits. Measurements of the distribution of echo power in time delay (range) and Doppler frequency (radial velocity) constitute two-dimensional images that can provide spatial resolution finer than a decameter. The best radar images reveal geologic details, including craters and blocks. Radar wavelengths (13 cm at Arecibo, 3.5 cm at Goldstone) are sensitive to the bulk density (a joint function of mineralogy and porosity) and the degree of decimeter-scale structural complexity of the uppermost meter or so of the surface. Radar can determine the masses of binary NEAs via Kepler's third law and of solitary NEAs via measurement of the Yarkovsky acceleration. With adequate orientational coverage, a sequence of images can be used to construct a three-dimensional model, to define the rotation state, to determine the distribution of radar surface properties, and to constrain the internal density distribution. As of mid 2006, radar has detected echoes from 193 NEAs, of which 107 are designated Potentially Hazardous Asteroids. Radar has revealed both stony and metallic objects, principal-axis and non-principal-axis rotators, smooth and extremely rough surfaces, objects that appear to be monolithic fragments and objects likely to be nearly strengthless gravitational aggregates, spheroids and highly elongated shapes, contact-binary shapes, and binary systems. Radar can add centuries to the interval over which close Earth approaches can accurately be predicted, significantly refining collision probability estimates compared to those based on optical astrometry alone. If a small body is on course for a collision with Earth in this century, delay-Doppler radar echoes could almost immediately let us recognize this by distinguishing between an impact trajectory and a near miss, and would dramatically reduce the difficulty and cost of any effort to prevent the collision.

  3. Extrasolar Asteroid Mining as Forensic Evidence for Extraterrestrial Intelligence

    CERN Document Server

    Forgan, Duncan

    2011-01-01

    The development of civilisations like ours into spacefaring, multi-planet entities requires significant raw materials to construct vehicles and habitats. Interplanetary debris, including asteroids and comets, may provide such a source of raw materials. In this article we present the hypothesis that extraterrestrial intelligences (ETIs) engaged in asteroid mining may be detectable from Earth. Considering the detected disc of debris around Vega as a template, we explore the observational signatures of targeted asteroid mining (TAM), such as unexplained deficits in chemical species, changes in the size distribution of debris and other thermal signatures which may be detectable in the spectral energy distribution (SED) of a debris disc. We find that individual observational signatures of asteroid mining can be explained by natural phenomena, and as such they cannot provide conclusive detections of ETIs. But, it may be the case that several signatures appearing in the same system will prove harder to model without...

  4. 313 new asteroid rotation periods from Palomar Transient Factory observations

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Chan-Kao; Ip, Wing-Huen; Lin, Hsing-Wen; Cheng, Yu-Chi; Ngeow, Chow-Choong; Yang, Ting-Chang [Institute of Astronomy, National Central University, Jhongli, Taiwan (China); Waszczak, Adam [Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125 (United States); Kulkarni, Shrinivas R.; Levitan, David; Sesar, Branimir; Prince, Thomas A. [Division of Physics, Mathematics and Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States); Laher, Russ; Surace, Jason, E-mail: rex@astro.ncu.edu.tw [Spitzer Science Center, California Institute of Technology, M/S 314-6, Pasadena, CA 91125 (United States)

    2014-06-10

    A new asteroid rotation period survey has been carried out by using the Palomar Transient Factory (PTF). Twelve consecutive PTF fields, which covered an area of 87 deg{sup 2} in the ecliptic plane, were observed in the R band with a cadence of ∼20 minutes during 2013 February 15-18. We detected 2500 known asteroids with a diameter range of 0.5 km ≤D ≤ 200 km. Of these, 313 objects had highly reliable rotation periods and exhibited the 'spin barrier' at ∼2 hr. In contrast to the flat spin-rate distribution of the asteroids with 3 km ≤D ≤ 15 km shown by Pravec et al., our results deviated somewhat from a Maxwellian distribution and showed a decrease at the spin rate greater than 5 rev day{sup –1}. One superfast rotator candidate and two possible binary asteroids were also found in this work.

  5. 313 new asteroid rotation periods from Palomar Transient Factory observations

    CERN Document Server

    Chang, Chan-Kao; Lin, Hsing-Wen; Cheng, Yu-Chi; Ngeow, Chow-Choong; Yang, Ting-Chang; Waszczak, Adam; Kulkarni, Shrinivas R; Levitan, David; Sesar, Branimir; Laher, Russ; Surace, Jason; Prince, Thomas A

    2014-01-01

    A new asteroid rotation period survey have been carried out by using the Palomar Transient Factory (PTF). Twelve consecutive PTF fields, which covered an area of 87 deg$^2$ in the ecliptic plane, were observed in $R$ band with a cadence of $\\sim$20 min during February 15--18, 2013. We detected 2500 known asteroids with a diameter range of 0.5 km $\\leq D \\leq$ 200 km. Of these, 313 objects had highly reliable rotation periods and exhibited the "spin barrier" at $\\sim2$ hours. In contrast to the flat spin rate distribution of the asteroids with 3 km $\\leq D \\leq$ 15 km shown by Pravec et al. (2008), our results deviated somewhat from a Maxwellian distribution and showed a decrease at the spin rate greater than 5 rev/day. One super-fast-rotator candidate and two possible binary asteroids were also found in this work.

  6. Hardersen IRTF Asteroid NIR Reflectance Spectra V1.0

    Science.gov (United States)

    Hardersen, P. S.

    2016-06-01

    This dataset includes average near-infrared (NIR) reflectance spectra for 68 main-belt asteroids that were observed at the NASA Infrared Telescope Facility (IRTF), Mauna Kea, Hawaii, from April 2001 to January 2015. Raw NIR spectral data were obtained under mostly uniform instrumental conditions and include observations of the asteroids, extinction stars, and solar analog stars that were necessary for data reduction and production of the final average asteroid NIR reflectance spectra. SpecPR and Spextool were used during data reduction to produce the final spectra and both programs utilize similar functions that include sky background subtraction, telluric corrections, channel shifting, and averaging routines. The set of asteroids observed include a wide variety of taxonomic types and include V-, S-, M-, X-types that correspond to a wide variety of surface mineralogies, rock types, and potential meteorite analogs.

  7. Constraints on the original ejection velocity fields of asteroid families

    CERN Document Server

    Carruba, Valerio

    2016-01-01

    Asteroid families form as a result of large-scale collisions among main belt asteroids. The orbital distribution of fragments after a family-forming impact could inform us about their ejection velocities. Unfortunately, however, orbits dynamically evolve by a number of effects, including the Yarkovsky drift, chaotic diffusion, and gravitational encounters with massive asteroids, such that it is difficult to infer the ejection velocities eons after each family's formation. Here we analyze the inclination distribution of asteroid families, because proper inclination can remain constant over long time intervals, and could help us to understand the distribution of the component of the ejection velocity that is perpendicular to the orbital plane ($v_{W}$). From modeling the initial breakup, we find that the distribution of $v_{W}$ of the fragments, which manage to escape the parent body's gravity, should be more peaked than a Gaussian distribution (i.e., be leptokurtic) even if the initial distribution was Gaussia...

  8. A polarimetric study of asteroids: Fitting phase - polarization curves

    CERN Document Server

    Cellino, A; Gil-Hutton, R; Tanga, P; Canada-Assandri, M; Tedesco, E F

    2015-01-01

    By considering all asteroid linear polarization data available in the literature, it is possible to obtain updated phase - polarization curves for several tens of objects. In a separate paper (Cellino et al., 2015a, MNRAS, 451, 3473) we have produced new calibrations of different relations between the geometric albedo and several polarimetric parameters, based on an analysis of a limited sample of asteroids for which the albedo is known with sufficient accuracy. In this paper, we present the main polarization parameters and corresponding albedos for a larger dataset of asteroids which we did not use for calibration purposes. We find a good agreement between the albedo values computed using different polarization parameters. Conversely, in the case of the so-called Barbarian asteroids the situation is rather unclear. Moreover, we present an updated analysis of the distributions of different polarimetric parameters, including the so-called inversion angle and the solar phase angle corresponding to the extreme v...

  9. Small Near-Earth Asteroids as a Source of Meteorites

    CERN Document Server

    Borovička, Jiří; Brown, Peter

    2015-01-01

    Small asteroids intersecting Earth's orbit can deliver extraterrestrial rocks to the Earth, called meteorites. This process is accompanied by a luminous phenomena in the atmosphere, called bolides or fireballs. Observations of bolides provide pre-atmospheric orbits of meteorites, physical and chemical properties of small asteroids, and the flux (i.e. frequency of impacts) of bodies at the Earth in the centimeter to decameter size range. In this chapter we explain the processes occurring during the penetration of cosmic bodies through the atmosphere and review the methods of bolide observations. We compile available data on the fireballs associated with 22 instrumentally observed meteorite falls. Among them are the heterogeneous falls Almahata Sitta (2008 TC$_3$) and Bene\\v{s}ov, which revolutionized our view on the structure and composition of small asteroids, the P\\v{r}\\'{\\i}bram-Neuschwanstein orbital pair, carbonaceous chondrite meteorites with orbits on the asteroid-comet boundary, and the Chelyabinsk fal...

  10. Detecting extrasolar asteroid belts through their microlensing signatures

    Science.gov (United States)

    Lake, Ethan; Zheng, Zheng; Dong, Subo

    2017-02-01

    We propose that extrasolar asteroid belts can be detected through their gravitational microlensing signatures. Asteroid belt + star lens systems create so-called 'pseudo-caustics', regions in the source plane where the magnification exhibits a finite but discontinuous jump. These features allow such systems to generate distinctive signatures in the microlensing light curves for a wide range of belt configurations, with source trajectories as far as tenths of the Einstein ring radius from the centre of the lens. Sample light curves for a range of asteroid belt parameters are presented. In the near future, space-based microlensing surveys like WFIRST, which will have the power of detecting per cent-level changes in microlensing light curves even with subminute exposure times, may be able to discover extrasolar asteroid belts with masses of the order of an earth mass.

  11. Radar observations of near-Earth asteroids from Arecibo Observatory

    Science.gov (United States)

    Rivera-Valentin, Edgard G.; Taylor, Patrick A.; Rodriguez-Ford, Linda A.; Zambrano Marin, Luisa Fernanda; Virkki, Anne; Aponte Hernandez, Betzaida

    2016-10-01

    The Arecibo S-Band (2.38 GHz, 12.6 cm, 1 MW) planetary radar system at the 305-m William E. Gordon Telescope in Arecibo, Puerto Rico is the most active and most sensitive planetary radar facility in the world. Since October 2015, we have detected 56 near-Earth asteroids, of which 17 are classified as potentially hazardous to Earth and 22 are compliant with the Near-Earth Object Human Space Flight Accessible Target Study (NHATS) as possible future robotic- or human-mission destinations. We will present a sampling of the asteroid zoo observed by the Arecibo radar since the 2015 DPS meeting. This includes press-noted asteroids 2015 TB145, the so-called "Great Pumpkin", and 2003 SD220, the so-called "Christmas Eve asteroid".

  12. Meteoroid impacts onto asteroids: a competitor for Yarkovsky and YORP

    CERN Document Server

    Wiegert, Paul A

    2014-01-01

    The impact of a meteoroid onto an asteroid transfers linear and angular momentum to the larger body, which may affect its orbit and its rotational state. Here we show that the meteoroid environment of our Solar System can have an effect on small asteroids that is comparable to the Yarkovsky and Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) effects under certain conditions. The momentum content of the meteoroids themselves is expected to generate an effect much smaller than that of the Yarkovsky effect. However, momentum transport by ejecta may increase the net effective force by two orders of magnitude for impacts into bare rock surfaces. This result is sensitive to the extrapolation of laboratory microcratering experiment results to real meteoroid-asteroid collisions and needs further study. If this extrapolation holds, then meteoroid impacts are more important to the dynamics of small asteroids than had previously been considered.

  13. Concept Design and Operation of an Asteroid Mining Vehicle

    Science.gov (United States)

    Claus, M.; Kumanan, D.

    2014-04-01

    The objective of this extended abstract is to provide an outline of the space activities undertaken within the astronautics group at Kingston University, before moving on to the current asteroid mining research.

  14. Asteroid thermal modeling in the presence of reflected sunlight

    Science.gov (United States)

    Myhrvold, Nathan

    2016-10-01

    This study addresses thermal modeling of asteroids with a new derivation of the Near Earth Asteroid Thermal (NEATM) model which correctly accounts for the presence of reflected sunlight in short wave IR bands. Kirchhoff's law of thermal radiation applies to this case and has important implications. New insight is provided into the ???? parameter in the NEATM model and it is extended to thermal models besides NEATM. The role of surface material properties on ???? is examined using laboratory spectra of meteorites and other asteroid compositional proxies; the common assumption that emissivity ????=0.9 in asteroid thermal models may not be justified and can lead to misestimating physical parameters. In addition, indeterminacy in thermal modeling can limit its ability to uniquely determine temperature and other physical properties. A new curve-fitting approach allows thermal modeling to be done independently of visible-band observational parameters, such as the absolute magnitude ????.

  15. Water and ice in asteroids: Connections between asteroid observations and the chondritic meteorite record

    Science.gov (United States)

    Schmidt, B.; Dyl, K.

    2014-07-01

    The mid-outer main belt is rich in possible parent bodies for the water-bearing carbonaceous chondrites, given their dark surfaces and frequent presence of hydrated minerals (e.g., Feierberg et al. 1985). Ceres (Thomas et al. 2005) and Pallas (Schmidt et al. 2009) possess shapes that indicate that these bodies have achieved hydrostatic equilibrium and may be differentiated (rock from ice). Dynamical calculations suggest asteroids formed rapidly to large sizes to produce the size frequency distribution within today's main belt (e.g., Morbidelli et al. 2009). Water-ice bound to organics has now been detected on the surface of Themis (Rivkin and Emery 2009, Campins et al. 2009), and indirect evidence for ice on many of the remaining family members, including main-belt comets (Hsieh & Jewitt 2006, Castillo-Rogez & Schmidt 2010), supports the theory that the ''C-class'' asteroids formed early and ice-rich. The carbonaceous chondrites represent a rich history of the thermal and aqueous evolution of early planetesimals (e.g., McSween 1979, Bunch and Chang, 1980, Zolensky and McSween 1988, Clayton 1993, Rowe et al., 1994). The composition of these meteorites reflects the timing and duration of water flow, as well as subsequent mineral alteration and isotopic evolution that can constrain temperature and water-rock ratios in which these systematics were set (e.g., Young et al. 1999, Dyl et al. 2012). Debate exists as to how the chemical and thermal consequences of fluid flow on carbonaceous chondrite parent bodies relate to parent-body characteristics: small, static water bodies (e.g., McSween 1979); small, convecting but homogeneous bodies (e.g., Young et al. 1999, 2003); or larger convecting bodies (e.g., Grimm and McSween 1989, Palguta et al. 2010). Heterogeneous thermal and aqueous evolution on larger asteroids that suggests more than one class of carbonaceous chondrite may be produced on the same body (e.g., Castillo-Rogez & Schmidt 2010, Elkins-Tanton et al. 2011

  16. In Search of Fresh Material on Asteroid Pairs

    Science.gov (United States)

    Polishook, David; Moskovitz, N.; Binzel, R. P.; DeMeo, F.; Vokrouhlicky, D.

    2013-10-01

    Asteroid Pairs are those found to share almost identical orbital elements. Studies have shown that each pair had a single progenitor that split in the last ~1 Myrs due to rotational-fission of a ‘rubble-pile’ structured body. This process may have exposed non-weathered sub-surface material, thus examining pairs' reflectance spectra could inform us about the physics of the rotational-fission mechanism. We report near-IR spectroscopic observations of a sample of 25 asteroid pairs, performed with the IRTF and Magellan telescopes. Since the rough division of the spectral taxonomy has arbitrary borders, and in order to quantify the extent of weathering, we analyzed the features of the spectra: the slope and the center and width of the 1-micron absorption band. We compared these values to those of asteroids of the background population that were measured in the same manner and were chosen to match the range of absolute magnitude and an orbit within the main belt. While the preliminary results show that the pairs’ band parameters are distributed most similarly to those of fresh objects (Q-type) than of weathered asteroids (S-type), a careful examination reveals that asteroid pairs of the Ordinary Chondrite type may be observationally biased towards Olivine-rich asteroids (the meteoritic LL-type) that share some of the band parameters of Q-type asteroids. Since Olivine-rich asteroids are more common in the inner main belt (the Flora family) they are just easier to observe, therefore more pairs are identified within this group, even though other types of asteroids can split by rotational-fission as well. The spectral slope distributions of asteroid pairs and of the background population resemble one another with no significant distinction. This suggests that on average, there may be no readily evident for excess in fresh material that is excavated and exposed on the surfaces of asteroid pairs. This leads to a model of a gentle breakup of the fast rotating progenitor

  17. Photometry of Main Belt and Trojan asteroids with K2

    Science.gov (United States)

    Szabó, Gyula; Kiss, Csaba; Pal, Andras; Szabo, Robert

    2016-10-01

    Due to the failure of the second reaction wheel, a new mission was conceived for the otherwise healthy Kepler space telescope. In the course of the K2 Mission, the telescope is staring at the plane of the Ecliptic, hence thousands of Solar System bodies cross the K2 fields, usually causing extra noise in the highly accurate photometric data.We could measure the first continuous asteroid light curves, covering several days wthout interruption, that has been unprecedented to date. We studied the K2 superstamps covering the M35 and Neptune/Nereid fields observed in the long cadence (29.4-min sampling) mode. Asteroid light curves are generated by applying elongated apertures. We investigated the photometric precision that the K2 Mission can deliver on moving Solar System bodies, and determined the first uninterrupted optical light curves of main-belt and Trojan asteroids. We use thed Lomb-Scargle method to find periodicities due to rotation.We derived K2 light curves of 924 main-belt asteroids in the M35 field, and 96 in the path of Neptune and Nereid. Due to the faintness of the asteroids and the high density of stars in the M35 field, 4.0% of the asteroids with at least 12 data points show clear periodicities or trend signalling a long rotational period, as opposed to 15.9% in the less crowded Neptune field. We found that the duty cycle of the observations had to reach ˜ 60% in order to successfully recover rotational periods.The derived period-amplitude diagram is consistent to the known distribution of Main Belt asteroids. For Trojan asteroids, the contribution of our 56 objects with newly determined precise period and amplitude is in the order of all previously known asteroids. The comparison with earth-based determinations showed a previous bias toward short periods and has also proven that asteroid periods >20 hour can be unreliable in a few cases because of daylight time and diurnal calibrations. These biases are avoided from the space. We present an unbiased

  18. A new mechanism for the formation of regolith on asteroids

    Science.gov (United States)

    Delbo, Marco; Libourel, Guy; Wilkerson, Justin; Murdoch, Naomi; Michel, Patrick; Ramesh, Kt; Ganino, Clement; Verati, Chrystele; Marchi, Simone

    2014-11-01

    The soil of asteroids, like that of the Moon, and other rocky, airless bodies in the Solar System, is made of a layer of pebbles, sand, and dust called regolith.Previous works suggested that the regolith on asteroids is made from material ejected from impacts and re-accumulated on the surface and from surface rocks that are broken down by micrometeoroid impacts. However, this regolith formation process has problems to explain the regolith on km-sized and smaller asteroids: it is known that impact fragments can reach escape velocities and breaks free from the gravitational forces of these small asteroids, indicating the impact mechanism is not the dominant process for regolith creation. Other studies also reveal that there is too much regolith on small asteroids’ surfaces to have been deposited there solely by impacts over the millions of years of asteroids’ evolution.We proposed that another process is capable of gently breaking rocks at the surface of asteroids: thermal fatigue by temperature cycling. As asteroids spin about their rotation axes, their surfaces go in and out of shadow resulting in large surface temperature variations. The rapid heating and cooling creates thermal expansion and contraction in the asteroid material, initiating cracking and propagating existing cracks. As the process is repeated over and over, the crack damage increases with time, leading eventually to rock fragmentation (and production of new regolith).To study this process, in the laboratory, we subjected meteorites, used as asteroid material analogs, to 37 days of thermal cycles similar to those occurring on asteroids. We measured cracks widening at an average rate of 0.5 mm/y. Some fragments were also produced, indicating meteorite fragmentation. To scale our results to asteroid lifetime, we incorporated our measurements into a fracture model and we deduced that thermal cycling is more efficient than micrometeorite bombardment at fragmenting rock over millions of years on

  19. Analyzing Serendipitous Asteroid Observations in Imaging Data using PHOTOMETRYPIPELINE

    Science.gov (United States)

    Ard, Christopher; Mommert, Michael; Trilling, David E.

    2016-10-01

    Asteroids are nearly ubiquitous in the night sky, making them present in the majority of imaging data taken every night. Serendipitous asteroid observations represent a treasure trove to Solar System researchers: accurate positional measurements of asteroids provide important constraints on their sometimes highly uncertain orbits, whereas calibrated photometric measurements can be used to establish rotational periods, intrinsic colors, or photometric phase curves.We present an add-on to the PHOTOMETRYPIPELINE (PP, github.com/mommermi/photometrypipeline, see Poster presentation 123.42) that identifies asteroids that have been observed serendipitously and extracts astrometry and calibrated photometry for these objects. PP is an open-source Python 2.7 software suite that provides image registration, aperture photometry, photometric calibration, and target identification with only minimal human interaction.Asteroids are identified based on approximate positions that are pre-calculated for a range of dates. Using interpolated coordinates, we identify potential asteroids that might be in the observed field and query their exact positions and positional uncertainties from the JPL Horizons system. The method results in robust astrometry and calibrated photometry for all asteroids in the field as a function of time. Our measurements will supplement existing photometric databases of asteroids and improve their orbits.We present first results using this procedure based on imaging data from the Vatican Advanced Technology Telescope.This work was done in the framework of NAU's REU summer program that is supported by NSF grant AST-1461200. PP was developed in the framework of the "Mission Accessible Near-Earth Object Survey" (MANOS) and is supported by NASA SSO grants NNX15AE90G and NNX14AN82G.

  20. The cool surfaces of binary near-Earth asteroids

    OpenAIRE

    Delbo, Marco; Walsh, Kevin; Mueller, Michael; Harris, Alan W.; Howell, Ellen S.

    2011-01-01

    Abstract Here we show results from thermal-infrared observations of km-sized binary Near-Earth Asteroids (NEAs). We combine previously published thermal properties for NEAs with newly derived values for three binary NEAs. The ?value derived from the Near-Earth Asteroid Thermal Model (NEATM) for each object is then used to estimate an average thermal inertia for the population of binary NEAs and compared against similar estimates for the population of non-binaries. We find that thes...

  1. Volatile Survival on Near-Earth Asteroid 2008 EV5

    Science.gov (United States)

    Pohl, Leos; Britt, Daniel

    2016-10-01

    Asteroid 2008 EV5 is currently one of the possible targets of NASA Asteroid Redirect Mission (ARM). The objective of this mission is to recover a boulder from the surface of an asteroid. The selection of the final target requires understanding the physical characteristics of the asteroid such as the size-frequency distribution of boulders on the asteroid's surface, the presence of volatiles on the surface and below, the strength of the surface materials and the degree of their alteration. In our work, we focus on the second criterion, the possibility of volatiles presence on 2008 EV5. These can be expected to survive embedded within the crystal lattice of various phyllosilicates. The positive presence of volatiles on the surface of and inside the asteroid is important especially for ISRU hardware demonstrations. Spectral data suggest that 2008 EV5 is a member of CI chondrite group which is characterized by high phyllosilicate content (~70%) but there is also the possibility of it being a CR chondrite where the phyllosilicate content ranges significantly, from samples with negligible phyllosilicate content to samples with almost 70% phyllosilicate content. If the dynamical history of the asteroid brought it close enough to the Sun, the lattice of phyllosilicates could have disintegrated and released the volatiles (water) and the material could have dehydrated. The depth at which the dehydration might have taken place depends on the characteristic depth of heat wave penetration which in turn depends on material characteristics such as density, heat capacity and heat conductivity. These are in turn are closely linked to the porosity. The characteristic heat penetration depth also depends on orbital geometry and rotational and orbital periods. Besides the temperature itself, the dehydration is also affected by the duration of the crystal lattice breakup temperatures. We use thermal model in conjunction with available experimental data on the dehydration of clays and

  2. Capturing small asteroids into a Sun-Earth Lagrangian point

    Science.gov (United States)

    Lladó, Neus; Ren, Yuan; Masdemont, Josep J.; Gómez, Gerard

    2014-02-01

    In this paper we address the feasibility of capturing small Near-Earth Asteroids (NEAs) into the vicinity of the Sun-Earth L2 libration point using a continuous-thrust propulsion system assumed to be attached to the asteroid. The vicinity of this libration point is a gateway to the Earth-Moon neighborhood and using it for capture, or for transit, small NEAs could be interesting for mining or science purposes.

  3. Extrasolar Asteroid Mining as Forensic Evidence for Extraterrestrial Intelligence

    OpenAIRE

    Forgan, Duncan; Elvis, Martin

    2011-01-01

    The development of civilisations like ours into spacefaring, multi-planet entities requires significant raw materials to construct vehicles and habitats. Interplanetary debris, including asteroids and comets, may provide such a source of raw materials. In this article we present the hypothesis that extraterrestrial intelligences (ETIs) engaged in asteroid mining may be detectable from Earth. Considering the detected disc of debris around Vega as a template, we explore the observational signat...

  4. The OSIRIS-REx Asteroid Sample Return Mission

    Science.gov (United States)

    Beshore, Edward; Lauretta, Dante; Boynton, William; Shinohara, Chriss; Sutter, Brian; Everett, David; Gal-Edd, Jonathan S.; Mink, Ronald G.; Moreau, Michael; Dworkin, Jason

    2015-01-01

    Interpretation, Resource Identification, Security, Regolith EXplorer) spacecraft will depart for asteroid (101955) Bennu, and when it does, humanity will turn an important corner in the exploration of the Solar System. After arriving at the asteroid in the Fall of 2018, it will undertake a program of observations designed to select a site suitable for retrieving a sample that will be returned to the Earth in 2023..

  5. Research on the tether assisted observation of an asteroid

    Science.gov (United States)

    Zhong, Rui; Wang, Yue

    2016-06-01

    The exploration of asteroids attracts much attention due to its potential in both scientific research and engineering application. However, the observation of an asteroid is a difficult task as the gravitational attraction of the asteroid is limited and complex. This paper proposes a concept of keeping probes in hovering above the asteroid by space tethers. The dynamics of a tethered probe attached to the surface of an asteroid is analyzed and the equations of motion are derived using Lagrange's equation. Then the equilibrium points of the dynamic system are calculated. The equilibrium tether libration angles are determined by the tether length and tether attaching location, while subjected to the constraint of positive tether tension. Afterwards, the stability of the equilibrium points are studied based on Lyapunov's theory. The variation of the equilibrium points with respect to the tether attaching location is numerically analyzed in the scenarios of different tether lengths. A parametric study of the stability of the equilibrium points is also provided. Finally, the dynamic behavior of a tethered probe perturbed from the equilibrium states is simulated to verify the proposed tether assisted technology for the observation of the asteroid.

  6. Delivery of organics to Mars through asteroid and comet impacts

    Science.gov (United States)

    Frantseva, Kateryna; Mueller, Michael; ten Kate, Inge L.; van der Tak, Floris

    2016-10-01

    Despite intensive search, the presence of organic molecules on Mars could only recently be demonstrated, through Curiosity measurements. On the surface of Mars, organics are highly unstable to photodissociation, but may last longer in the subsurface. It is therefore believed that organics observable today were delivered in geologically recent times; possible parent bodies are certain asteroids, comets, and/orinterplanetary dust particles.We are studying how much organics the known asteroids and comets can deliver to Mars. Comets and certain asteroids (C-class) are known to be organic rich.To this end we perform numerical gravity simulations to study impact rates on Mars within the past few Myr. We use the N-body integrator RMVS/Swifter to propagate the Sun and the eight planets from their current positions. We separately add comets and asteroids to the simulations as massless test particles, based on their current orbital distributions. In our asteroid simulations we differentiate between organic-rich (C-class) asteroids and other taxonomic types, using WISE albedo as a proxy. We expect to present first results at the meeting.

  7. Study of the Dynamics of Asteroids - Companions to Venus

    Science.gov (United States)

    Galushina, T. Yu.; Skripnichenko, P. V.; Titarenko, E. Yu.

    2017-01-01

    The present work is devoted to a study of motion of near-Earth asteroids (NEA) 2002 VE68 and 2013 ND15 moving in the vicinity of the 1:1 resonance with Venus. To construct the probability domain of these NEA, 10 thousand clones covering the initial probability domain of the object were used. The investigation time intervals chosen individually are 4500 and 1520 years, respectively. The orbit of asteroid 2013 ND15 is illdefined that allows no conclusion to be made on its capture in a resonance. The given object regularly approaches to Mercury, Venus, and the Earth thereby causing a substantial growth of the probability domain. Our study shows that new observations of the asteroid from the Earth surface are impossible till 2021. An analysis of the evolution of the average MEGNO parameter demonstrates that the predictability time of motion of the given object is about 250 years. Asteroid 2002 VE68 behaves differently. A study of perturbation structure demonstrates that for this object it is necessary to take into account the influence of major planets, the Moon, the Sun oblateness, and relativistic effects of the Sun. On the entire investigation time interval the asteroid moves in the vicinity of stable resonance and its critical argument librates. Asteroid 2002 VE68 approaches to Mercury and Venus, but not very close. The predictability time of motion is about 800 years.

  8. On the puzzle of space weathering alteration of basaltic asteroids

    CERN Document Server

    Marchi, S; Lazzarin, M; Magrin, S

    2010-01-01

    The majority of basaltic asteroids are found in the inner main belt, although a few have also been observed in the outer main belt and near-Earth space. These asteroids -referred to as V-types- have surface compositions that resemble that of the 530km sized asteroid Vesta. Besides the compositional similarity, dynamical evidence also links many V-type asteroids to Vesta. Moreover, Vesta is one of the few asteroids to have been identified as source of specific classes of meteorites, the howardite, eucrite, diogenite achondrites (HEDs). Despite the general consensus on the outlined scenario, several questions remain unresolved. In particular, it is not clear if the observed spectral diversity among Vesta, V-types and HEDs is due to space weathering, as is thought to be the case for S-type asteroids. In this paper, SDSS photometry is used to address the question of whether the spectral diversity among candidate V-types and HEDs can be explained by space weathering. We show that visible spectral slopes of V-types...

  9. NEOWISE Studies of Asteroids with Sloan Photometry: Preliminary Results

    CERN Document Server

    Mainzer, A; Grav, T; Bauer, J; Tholen, D J; McMillan, R S; Wright, E; Spahr, T; Cutri, R M; Walker, R; Mo, W; Watkins, J; Hand, E; Maleszewski, C

    2011-01-01

    We have combined the NEOWISE and Sloan Digital Sky Survey data to study the albedos of 24,353 asteroids with candidate taxonomic classifications derived using Sloan photometry. We find a wide range of moderate to high albedos for candidate S-type asteroids that are analogous to the S-complex defined by previous spectrophotometrically-based taxonomic systems. The candidate C-type asteroids, while generally very dark, have a tail of higher albedos that overlaps the S types. The albedo distribution for asteroids with a photometrically derived Q classification is extremely similar to those of the S types. Asteroids with similar colors to (4) Vesta have higher albedos than the S types, and most have orbital elements similar to known Vesta family members. Finally, we show that the relative reflectance at 3.4 and 4.6 $\\mu$m is higher for D-type asteroids and suggest that their red visible and near-infrared spectral slope extends out to these wavelengths. Understanding the relationship between size, albedo, and taxon...

  10. V-type asteroids in the middle Main Belt

    CERN Document Server

    Roig, F; Gil-Hutton, R; Lazzaro, D

    2007-01-01

    The recent discovery of the first V-type asteroid in the middle belt, (21238) 1995WV7, located at ~2.54 AU, raises the question of whether it came from (4) Vesta or not. In this paper, we present spectroscopic observations indicating the existence of another V-type asteroid at ~2.53 AU, (40521) 1999RL95, and we investigate the possibility that these two asteroids evolved from the Vesta family to their present orbits by drifting in semi-major axis due to the Yarkovsky effect. The main problem with this scenario is that the asteroids need to cross the 3/1 mean motion resonance with Jupiter, which is highly unstable. Combining numerical simulations of the orbital evolution, that include the Yarkovsky effect, with Monte Carlo models, we compute the probability of an asteroid of given diameter D to evolve from the Vesta family and to cross over the 3/1 resonance, reaching a stable orbit in the middle belt. Our results indicate that an asteroid like (21238) 1995WV7 has a low probability of having evolved through th...

  11. The effect of asteroid topography on surface ablation deflection

    Science.gov (United States)

    McMahon, Jay W.; Scheeres, Daniel J.

    2017-02-01

    Ablation techniques for deflecting hazardous asteroids deposit energy into the asteroid's surface, causing an effective thrust on the asteroid as the ablating material leaves normal to the surface. Although it has long been recognized that surface topography plays an important role in determining the deflection capabilities, most studies to date have ignored this aspect of the model. This paper focuses on understanding the topography for real asteroid shapes, and how this topography can change the deflection performance of an ablation technique. The near Earth asteroids Golevka, Bennu, and Itokawa are used as the basis for this study, as all three have high-resolution shape models available. This paper shows that naive targeting of an ablation method without accounting for the surface topography can lower the deflection performance by up to 20% in the cases studied in terms of the amount of acceleration applied in the desired direction. If the ablation thrust level is assumed to be 100 N, as used elsewhere in the literature, this misapplication of thrust translates to tens of kilometers per year in decreased semimajor axis change. However, if the ablation method can freely target any visible point on the surface of the asteroid, almost all of this performance can be recovered.

  12. A Novel and Simple Means to Estimate Asteroid Thermal Inertia

    Science.gov (United States)

    Drube, Line; Harris, Alan

    2016-10-01

    Calculating accurate values of thermal inertia for asteroids is a difficult process requiring a shape model, thermal-infrared observations of the object obtained over broad ranges of rotation period and aspect angle, and detailed thermophysical modeling. Consequently, reliable thermal inertia values are currently available for relatively few asteroids. On the basis of simple asteroid thermal modeling we have developed an empirical relationship enabling the thermal inertia of an asteroid to be estimated given adequate measurements of its thermal-infrared continuum and knowledge of its spin vector. In particular, our thermal-inertia estimator can be applied to hundreds of objects in the WISE cryogenic archive (limited by the availability of spin vectors). To test the accuracy of our thermal-inertia estimator we have used it to estimate thermal inertia for near-Earth asteroids, main-belt asteroids, Centaurs, and trans-Neptunian objects with known thermal inertia values derived from detailed thermophysical modeling. In nearly all cases the estimates agree within the error bars with the values derived from thermophysical modeling.

  13. Spacecraft Conceptual Design for Returning Entire Near-Earth Asteroids

    Science.gov (United States)

    Brophy, John R.; Oleson, Steve

    2012-01-01

    In situ resource utilization (ISRU) in general, and asteroid mining in particular are ideas that have been around for a long time, and for good reason. It is clear that ultimately human exploration beyond low-Earth orbit will have to utilize the material resources available in space. Historically, the lack of sufficiently capable in-space transportation has been one of the key impediments to the harvesting of near-Earth asteroid resources. With the advent of high-power (or order 40 kW) solar electric propulsion systems, that impediment is being removed. High-power solar electric propulsion (SEP) would be enabling for the exploitation of asteroid resources. The design of a 40-kW end-of-life SEP system is presented that could rendezvous with, capture, and subsequently transport a 1,000-metric-ton near-Earth asteroid back to cislunar space. The conceptual spacecraft design was developed by the Collaborative Modeling for Parametric Assessment of Space Systems (COMPASS) team at the Glenn Research Center in collaboration with the Keck Institute for Space Studies (KISS) team assembled to investigate the feasibility of an asteroid retrieval mission. Returning such an object to cislunar space would enable astronaut crews to inspect, sample, dissect, and ultimately determine how to extract the desired materials from the asteroid. This process could jump-start the entire ISRU industry.

  14. Metalliferous asteroids as potential sources of precious metals

    Science.gov (United States)

    Kargel, Jeffrey S.

    1994-10-01

    Recent discoveries of near-Earth asteroids (NEAs) and chemical analyses of fragments of asteroids (meteorites) suggest that there may be a gold mine, literally, in near-Earth space. Judged from meteorite analyses, two types of asteroids offer particularly bright prospects for recovery of large quantities of precious metals (defined as Au, Pt, Ir, Os, Pd, Rh, and Ru), the ordinary LL chondrites, which contain 1.2-5.3% Fe-Ni metal containing 50-220 ppm of precious metals, and metallic asteroids, which consist almost wholly of Fe-Ni phases and contain variable amounts of precious metals up to several hundred ppm. The pulverized regolith of LL chondrite asteroids could be electromagnetically raked to separate the metallic grains. Suitable metallic asteroids could be processed in their entirety. Statistically, there should be approximately six metallic NEAs larger than 1 km in diameter that contain over 100 ppm of precious metals. Successful recovery of 400,000 tons or more of precious metals contained in the smallest and least rich of these metallic NEAs could yield products worth $5.1 trillion (US) at recent market prices.

  15. Control of asteroid retrieval trajectories to libration point orbits

    Science.gov (United States)

    Ceriotti, Matteo; Sanchez, Joan Pau

    2016-09-01

    The fascinating idea of shepherding asteroids for science and resource utilization is being considered as a credible concept in a not too distant future. Past studies identified asteroids which could be efficiently injected into manifolds which wind onto periodic orbits around collinear Lagrangian points of the Sun-Earth system. However, the trajectories are unstable, and errors in the capture maneuver would lead to complete mission failure, with potential danger of collision with the Earth, if uncontrolled. This paper investigates the controllability of some asteroids along the transfers and the periodic orbits, assuming the use of a solar-electric low-thrust system shepherding the asteroid. Firstly, an analytical approach is introduced to estimate the stability of the trajectories from a dynamical point of view; then, a numerical control scheme based on a linear quadratic regulator is proposed, where the gains are optimized for each trajectory through a genetic algorithm. A stochastic simulation with a Monte Carlo approach is used to account for different perturbed initial conditions and the epistemic uncertainty on the asteroid mass. Results show that only a small subset of the considered combinations of trajectories/asteroids are reliably controllable, and therefore controllability must be taken into account in the selection of potential targets.

  16. Dynamical transport of asteroid fragments from the nu6 resonance

    CERN Document Server

    Ito, T; Ito, Takashi; Malhotra, Renu

    2006-01-01

    A large disruption in the main asteroid belt can cause a large flux, an "asteroid shower", on the terrestrial planets. We quantitatively examine the hypothesis that such an event was the cause of the lunar late heavy bombardment (LHB). We performed numerical integrations of about 20000 test particles starting in the vicinity of the nu6 secular resonance in the main asteroid belt. The purpose of these integrations is to calculate, for each of the terrestrial planets, the collision probability of asteroids coming from an asteroid break-up event in the inner part of the main belt. Compared with previous studies, we simulate nearly two orders of magnitude larger number of particles, and we include the orbital effects of the eight planets, Mercury to Neptune. We also examined in detail the orbital evolution of asteroid fragments once they enter the Earth's activity sphere, including the effect of the Earth-Moon orbit. We obtained the collision probability, the distributions of impact velocities, impact positions, ...

  17. The composition of the Eureka family of Martian Trojan asteroids

    Science.gov (United States)

    Borisov, Galin; Christou, Apostolos; Bagnulo, Stefano

    2016-10-01

    The so-called Martian Trojan asteroids orbit the Sun just inside the terrestrial planet region. They are thought to date from the earliest period of the solar system's history (Scholl et al, Icarus, 2005). Recently, Christou (Icarus, 2013) identified an orbital concentration of Trojans, named the "Eureka" cluster after its largest member, 5261 Eureka. This asteroid belongs to the rare olivine-rich A taxonomic class (Rivkin et al, Icarus, 2007; Lim et al, DPS/EPSC 2011). Unlike asteroids belonging to other taxonomies (e.g. C or S), no orbital concentrations or families of A-types are currently known to exist. These asteroids may represent samples of the building blocks that came together to form Mars and the other terrestrial planets but have since been destroyed by collisions (Sanchez et al, Icarus, 2014, and references therein).We have used the X-SHOOTER echelle spectrograph on the ESO VLT KUEYEN to obtain vis-NIR reflectance spectra of asteroids in the cluster and test their genetic relationship to Eureka. During the presentation we will show the spectra, compare them with available spectra for Eureka itself and discuss the implications for the origin of this cluster and for other olivine-dominated asteroids in the Main Belt.Based on observations made with ESO Telescopes at the La Silla-Paranal Observatory under programme ID 296.C-5030 (PI: A. Christou). Astronomical Research at Armagh Observatory is funded by the Northern Ireland Department of Culture, Arts and Leisure (DCAL).

  18. A search for differentiated fragments within asteroid families

    Science.gov (United States)

    DeMeo, Francesca E.; Carry, Benoit; Polishook, David; Binzel, Richard; Burt, Brian; Moskovitz, Nicholas

    2016-10-01

    The existence of iron meteorite samples suggest that a number of planetesimals differentiated fully and were subsequently disrupted. Within the current asteroid belt, there is little evidence of bodies that fully differentiated into core, mantle and crust layers (Moskovitz et al. 2008). However, because it has been suggested that differentiation can occur within the interior of a body while the primitive exterior remains intact (Elkins-Tanton et al. 2011), an understanding of the diversity of compositions from differentiated parent bodies is critical. Asteroid families, as constituents of a disrupted progenitor body, provide a glimpse into the interior of their progenitors. However, asteroid families, while spectrally unique from one another, are spectrally similar within each family (Parker et al., 2008, Masiero et al. 2011). Using the Sloan Digital Sky Survey (SDSS) to search for a "needle in a haystack" we identify candidate basaltic and olivine-rich asteroids that are dynamically associated with asteroid families to constrain the amount of differentiation that could have occurred within the parent asteroid. Using FIRE on the 6-meter Magellan Telescope and SpeX on the 3-meter IRTF Telescope we measure near-infrared spectra of more than thirty of these candidates, most of which are part of the Eunomia and Flora families. Results of these observations are presented in this talk.

  19. Science case for the Asteroid Impact Mission (AIM): A component of the Asteroid Impact & Deflection Assessment (AIDA) mission

    Science.gov (United States)

    Michel, Patrick; Cheng, A.; Küppers, M.; Pravec, P.; Blum, J.; Delbo, M.; Green, S. F.; Rosenblatt, P.; Tsiganis, K.; Vincent, J. B.; Biele, J.; Ciarletti, V.; Hérique, A.; Ulamec, S.; Carnelli, I.; Galvez, A.; Benner, L.; Naidu, S. P.; Barnouin, O. S.; Richardson, D. C.; Rivkin, A.; Scheirich, P.; Moskovitz, N.; Thirouin, A.; Schwartz, S. R.; Campo Bagatin, A.; Yu, Y.

    2016-06-01

    The Asteroid Impact & Deflection Assessment (AIDA) mission is a joint cooperation between European and US space agencies that consists of two separate and independent spacecraft that will be launched to a binary asteroid system, the near-Earth asteroid Didymos, to test the kinetic impactor technique to deflect an asteroid. The European Asteroid Impact Mission (AIM) is set to rendezvous with the asteroid system to fully characterize the smaller of the two binary components a few months prior to the impact by the US Double Asteroid Redirection Test (DART) spacecraft. AIM is a unique mission as it will be the first time that a spacecraft will investigate the surface, subsurface, and internal properties of a small binary near-Earth asteroid. In addition it will perform various important technology demonstrations that can serve other space missions. The knowledge obtained by this mission will have great implications for our understanding of the history of the Solar System. Having direct information on the surface and internal properties of small asteroids will allow us to understand how the various processes they undergo work and transform these small bodies as well as, for this particular case, how a binary system forms. Making these measurements from up close and comparing them with ground-based data from telescopes will also allow us to calibrate remote observations and improve our data interpretation of other systems. With DART, thanks to the characterization of the target by AIM, the mission will be the first fully documented impact experiment at asteroid scale, which will include the characterization of the target's properties and the outcome of the impact. AIDA will thus offer a great opportunity to test and refine our understanding and models at the actual scale of an asteroid, and to check whether the current extrapolations of material strength from laboratory-scale targets to the scale of AIDA's target are valid. Moreover, it will offer a first check of the

  20. Asteroid observations with the Hubble Space Telescope and the Space Infrared Telescope Facility

    Science.gov (United States)

    Zellner, B.; Wells, Eddie N.; Chapman, Clark R.; Cruikshank, D. P.

    1989-01-01

    The ways that the asteroids can be studied with the Hubble Space Telescope (HST) and the Space Infrared Telescope Facility (SIRTF) are examined. Spectrophotometry of asteroids and the study of asteroid surfaces, shape, spins, configuration, normal reflectance, and limb darkening of asteroids using the HST are addressed along with the detection of asteroid satellites and the discovery of small asteroids using the HST. The relation of the HST to its ground system is described, as are the spectrophotometric instruments of the HST. Imaging with the HST using the Faint Object Camera and the Wide Field and Planetary Camera is examined. Finally, the SIRTF observatory, instrumentation, and capabilities for solar system science are discussed.

  1. Near Earth Asteroid redirect missions based on gravity assist maneuver

    Science.gov (United States)

    Ledkov, Anton; Shustov, Boris M.; Eismont, Natan; Boyarsky, Michael; Nazirov, Ravil; Fedyaev, Konstantin

    During last years several events attracted world community attention to the hazards of hitting the Earth by sky objects. One of these objects is Apophis asteroid what was expected with nonzero probability to hit the Earth in 2036. Luckily after more precise measurements this event is considered as practically improbable. But the other object has really reached the Earth, entered the atmosphere in the Chelyabinsk area and caused vast damages. After this the hazardous near Earth objects problem received practical confirmation of the necessity to find the methods of its resolution. The methods to prevent collision of the dangerous sky object with the Earth proposed up to now look not practical enough if one mentions such as gravitational tractor or changing the reflectivity of the asteroid surface. Even the method supposing the targeting of the spacecraft to the hazardous object in order to deflect it from initial trajectory by impact does not work because its low mass as compared with the mass of asteroid to be deflected. For example the mass of the Apophis is estimated to be about 40 million tons but the spacecraft which can be launched to intercept the asteroid using contemporary launchers has the mass not more than 5 tons. So the question arises where to find the heavier projectile which is possible to direct to the dangerous object? The answer proposed in our paper is very simple: to search it among small near Earth asteroids. As small ones we suppose those which have the cross section size not more than 12-15 meters and mass not exceeding 1500 -1700 tons. According to contemporary estimates the number of such asteroids is not less than 100000. The other question is how to redirect such asteroid to the dangerous one. In the paper the possibilities are studied to use for that purpose gravity assist maneuvers near Earth. It is shown that even among asteroids included in contemporary catalogue there are the ones which could be directed to the trajectory of the

  2. Large Halloween asteroid at lunar distance

    Science.gov (United States)

    Müller, T. G.; Marciniak, A.; Butkiewicz-Bąk, M.; Duffard, R.; Oszkiewicz, D.; Käufl, H. U.; Szakáts, R.; Santana-Ros, T.; Kiss, C.; Santos-Sanz, P.

    2017-02-01

    The near-Earth asteroid (NEA) 2015 TB145 had a very close encounter with Earth at 1.3 lunar distances on October 31, 2015. We obtained 3-band mid-infrared observations of this asteroid with the ESO VLT-VISIR instrument covering approximately four hours in total. We also monitored the visual lightcurve during the close-encounter phase. The NEA has a (most likely) rotation period of 2.939 ± 0.005 h and the visual lightcurve shows a peak-to-peak amplitude of approximately 0.12 ± 0.02 mag. A second rotation period of 4.779 ± 0.012 h, with an amplitude of the Fourier fit of 0.10 ± 0.02 mag, also seems compatible with the available lightcurve measurements. We estimate a V-R colour of 0.56 ± 0.05 mag from different entries in the MPC database. A reliable determination of the object's absolute magnitude was not possible. Applying different phase relations to the available R-/V-band observations produced HR = 18.6 mag (standard H-G calculations) or HR = 19.2 mag and HV = 19.8 mag (via the H-G12 procedure for sparse and low-quality data), with large uncertainties of approximately 1 mag. We performed a detailed thermophysical model analysis by using spherical and partially also ellipsoidal shape models. The thermal properties are best explained by an equator-on (±≈30°) viewing geometry during our measurements with a thermal inertia in the range 250-700 J m-2 s-0.5 K-1 (retrograde rotation) or above 500 J m-2 s-0.5 K-1 (prograde rotation). We find that the NEA has a minimum size of approximately 625 m, a maximum size of just below 700 m, and a slightly elongated shape with a/b ≈ 1.1. The best match to all thermal measurements is found for: (i) thermal inertia Γ = 900 J m-2 s-0.5 K-1; Deff = 644 m, pV = 5.5% (prograde rotation with 2.939 h); regolith grain sizes of ≈50-100 mm; (ii) thermal inertia Γ = 400 J m-2 s-0.5 K-1; Deff = 667 m, pV = 5.1% (retrograde rotation with 2.939 h); regolith grain sizes of ≈10-20 mm. A near-Earth asteroid model (NEATM) confirms

  3. AsteroidFinder - The Space-Borne Telescope to Search for NEO Asteroids

    Science.gov (United States)

    Hartl, M.; Mosebach, H.; Schubert, J.; Michaelis, H.; Mottola, S.; Kührt, E.; Schindler, K.

    2010-10-01

    This paper presents the mission profile as well as the optical configuration of the space-borne AsteroidFinder telescope. Its main objective is to retrieve asteroids with orbits interior to the earth's orbit. The instrument requires high sensitivity to detect asteroids with a limiting magnitude of equal or larger than 18.5mag (V-Band) and astrometric accuracy of 1arcsec (1σ). This requires a telescope aperture greater than 400cm2, high image stability, detector with high quantum efficiency (peak > 90%) and very low noise, which is only limited by zodiacal background. The telescope will observe the sky between 30° and 60° in solar elongation. The telescope optics is based on a Cook type TMA. An effective 2°×2° field of view (FOV) is achieved by a fast F/3.4 telescope with near diffraction-limited performance. The absence of centre obscuration or spiders in combination with an accessible intermediate field plane and exit pupil allow for efficient stray light mitigation. Design drivers for the telescope are the required point spread function (PSF) values, an extremely efficient stray light suppression (due to the magnitude requirement mentioned above), the detector performance, and the overall optical and mechanical stability for all orientations of the satellite. To accommodate the passive thermal stabilization scheme and the necessary structural stability, the materials selection for the telescope main structure and the mirrors are of vital importance. A focal plane with four EMCCD detectors is envisaged. The EMCCD technology features shorter integration times, which is in favor regarding the pointing performance of the satellite. The launch of the mission is foreseen for the year 2013 with a subsequent mission lifetime of at least 1 year.

  4. The Double Asteroid Redirection Test in the AIDA Project

    Science.gov (United States)

    Cheng, Andrew; Rivkin, Andrew; Michel, Patrick

    2016-04-01

    The Asteroid Impact & Deflection Assessment (AIDA) mission will be the first space experiment to demonstrate asteroid impact hazard mitigation by using a kinetic impactor. AIDA is a joint ESA-NASA cooperative project, that includes the ESA Asteroid Impact Mission (AIM) rendezvous mission and the NASA Double Asteroid Redirection Test (DART) mission. The AIDA target is the near-Earth binary asteroid 65803 Didymos, which will make an unusually close approach to Earth in October, 2022. The ~300-kg DART spacecraft is designed to impact the Didymos secondary at 7 km/s and demonstrate the ability to modify its trajectory through momentum transfer. DART and AIM are currently Phase A studies supported by NASA and ESA respectively. The primary goals of AIDA are (1) perform a full-scale demonstration of the spacecraft kinetic impact technique for deflection of an asteroid, by targeting an object larger than ~100 m and large enough to qualify as a Potentially Hazardous Asteroid; (2) measure the resulting asteroid deflection, by targeting the secondary member of a binary NEO and measuring the period change of the binary orbit; (3) understand the hyper-velocity collision effects on an asteroid, including the long-term dynamics of impact ejecta; and validate models for momentum transfer in asteroid impacts, based on measured physical properties of the asteroid surface and sub-surface. The primary DART objectives are to demonstrate a hyper-velocity impact on the Didymos moon and to determine the resulting deflection from ground-based observatories. The DART impact on the Didymos secondary will cause a measurable change in the orbital period of the binary. Supporting Earth-based optical and radar observations and numerical simulation studies are an integral part of the DART mission. The baseline DART mission launches in December, 2020 to impact the Didymos secondary in September, 2022. There are multiple launch opportunities for DART leading to impact around the 2022 Didymos close

  5. Reconstructing the spin distributions of main-belt asteroids

    Science.gov (United States)

    Holsapple, K.

    2014-07-01

    INTRODUCTION: We now have spin data for almost six thousand asteroids, each value being a result of that asteroid's history. Some features of that distribution are now evident. The gravity spin limit at the period of about 2.3 h for asteroids with a diameter greater than a few kilometers is well established (Harris 1996, Pravec and Harris 2000, Holsapple 2001, and others). The strength of smaller asteroids as inferred from the ''fast spinners'' has been presented by Holsapple (2007), Sanchez and Scheeres (2014), and others. Several statistical analyses of the database have been presented (e.g., Pravec and Harris 2002). Here that database is used as a means of investigating the prior history of the asteroid belt. THEORETICAL APPROACHES: A way to understand the data is to attempt to reproduce it using theoretical models and numerical simulations of the physics of the processes that created it. Such studies have evolved since McAdoo and Burns (1973) first suggested collisions as a source of the spins; they include Davis et al. (1979), Dobrovolskis and Burns (1984), Harris (1979), Davis et al. (1989), Farinella et al. (1992), Henych and Pravec (2013), and others. These analyses are based upon averaging the effects of a number of individual impacts into a given target asteroid. I retrace the path and analyses of those authors in this work, but make important modifications and updates. The primary elements introduced in those prior studies include: 1) a population of asteroids in a given space; 2) a distribution of impact velocities and angles; 3) the efficiency of angular-momentum transfer in an impact; 4) the loss or gain of mass and angular inertia; 5) the amount, direction, and speed of the cratering ejecta. The characteristics of the ejecta are especially important: they determine the ''angular-momentum drain'' first identified by Dobrovolskis and Burns (1984). It is caused by the preferential escape of ejecta in the downrange spin direction. Here I revisit, update

  6. Asteroid Geophysics and Quantifying the Impact Hazard

    Science.gov (United States)

    Sears, D.; Wooden, D. H.; Korycanksy, D. G.

    2015-01-01

    Probably the major challenge in understanding, quantifying, and mitigating the effects of an impact on Earth is understanding the nature of the impactor. Of the roughly 25 meteorite craters on the Earth that have associated meteorites, all but one was produced by an iron meteorite and only one was produced by a stony meteorite. Equally important, even meteorites of a given chemical class produce a wide variety of behavior in the atmosphere. This is because they show considerable diversity in their mechanical properties which have a profound influence on the behavior of meteorites during atmospheric passage. Some stony meteorites are weak and do not reach the surface or reach the surface as thousands of relatively harmless pieces. Some stony meteorites roll into a maximum drag configuration and are strong enough to remain intact so a large single object reaches the surface. Others have high concentrations of water that may facilitate disruption. However, while meteorite falls and meteorites provide invaluable information on the physical nature of the objects entering the atmosphere, there are many unknowns concerning size and scale that can only be determined by from the pre-atmospheric properties of the asteroids. Their internal structure, their thermal properties, their internal strength and composition, will all play a role in determining the behavior of the object as it passes through the atmosphere, whether it produces an airblast and at what height, and the nature of the impact and amount and distribution of ejecta.

  7. The Complex History of Trojan Asteroids

    CERN Document Server

    Emery, Joshua P; Morbidelli, Alessandro; French, Linda M; Grav, Tommy

    2015-01-01

    The Trojan asteroids provide a unique perspective on the history of Solar System. As a large population of small bodies, they record important gravitational interactions and dynamical evolution of the Solar System. In the past decade, significant advances have been made in understanding physical properties, and there has been a revolution in thinking about the origin of Trojans. The ice and organics generally presumed to be a significant part of Trojan compositions have yet to be detected directly, though low density of the binary system Patroclus (and possibly low density of the binary/moonlet system Hektor) is consistent with an interior ice component. By contrast, fine-grained silicates that appear to be similar to cometary silicates in composition have been detected, and a color bimodality may indicate distinct compositional groups among the Trojans. Whereas Trojans had traditionally been thought to have formed near 5 AU, a new paradigm has developed in which the Trojans formed in the proto-Kuiper Belt, a...

  8. New Active Asteroid 313P/Gibbs

    CERN Document Server

    Jewitt, David; Peixinho, Nuno; Weaver, Harold; Mutchler, Max; Hui, Man-To; Li, Jing; Larson, Stephen

    2014-01-01

    We present initial observations of the newly-discovered active asteroid 313P/Gibbs (formerly P/2014 S4), taken to characterize its nucleus and comet-like activity. The central object has a radius $\\sim$0.5 km (geometric albedo 0.05 assumed). We find no evidence for secondary nuclei and set (with qualifications) an upper limit to the radii of such objects near 25 m, assuming the same albedo. Both aperture photometry and a morphological analysis of the ejected dust show that mass-loss is continuous at rates $\\sim$0.2 to 0.4 kg s$^{-1}$, inconsistent with an impact origin. Large dust particles, with radii $\\sim$50 to 100 $\\mu$m, dominate the optical appearance. At 2.4 AU from the Sun, the surface equilibrium temperatures are too low for thermal or desiccation stresses to be responsible for the ejection of dust. No gas is spectroscopically detected (limiting the gas mass loss rate to $<$1.8 kg s$^{-1}$). However, the protracted emission of dust seen in our data and the detection of another episode of dust rele...

  9. Un asteroide proveniente de la Luna

    Science.gov (United States)

    Tancredi, G.

    El descubrimiento de un débil objeto en movimiento por el telescopio Spacewatch (un instrumento dedicado a la búsqueda de Asteroides Cercanos a la Tierra) en 1991, ha generado una gran controversia en la comunidad planetaria. El objeto, denominado 1991 VG, tiene elementos orbitales llamativamente similares a los de la Tierra, lo que ha llevado a B. G. Marsden a aventurar:``El objeto podría ser una nave espacial en retorno (IAUC 5387)". Luego de analizar las características dinámicas de 1991 VG y las diferentes hipótesis sobre su origen, favorecemos la alternativa de que el objeto es un gran fragmento de material eyectado de la Luna durante un reciente impacto (en las últimas decenas de miles de años). El hallazgo en 1983 en la Antártida de meteoritos con composición tipo lunar, confirma la posibilidad de que material de la superficie del satélite puede ser eyectado a velocidades superiores a la de escape del sistema Tierra-Luna y alcance órbitas heliocéntricas. Los elementos orbitales de 1991 VG corresponden a los valores alcanzados por partículas que apenas escapan de la gravedad lunar y entran en órbitas heliocéntricas a través del punto Lagrangiano exterior del sistema Tierra-Sol.

  10. Asteroid hyalosis: clinical review of 58 cases

    Directory of Open Access Journals (Sweden)

    José Nuno Vargas Galveia

    2013-10-01

    Full Text Available OBJECTIVE: Understand the behavior, functional repercussion and relationship with epidemiological factors of asteroid hyalosis (AH and retrospective observational case series. METHODS: Fifty-eight patients diagnosed with AH (24 women and 34 men were studied. All patients were submitted to a thorough ophthalmological examination. RESULTS: We observed a statistical association between the presence of AH and male sex (p=0,042. An increase in prevalence of this pathology was observed with increasing age. We determined an odds ration of 5,24 of a patient over 50 years old having AH, when compared to patients bellow this threshold. Eighty-six percent of patients had unilateral vitreous deposits. We measured a lower IOP in the affected eye, with the difference being in average 2,68 ± 1,45 mmHg (p=0,037. We observed no statistical association between AH and age related macular degeneration, diabetes or glaucoma. Five eyes were submitted to facoemulsification combined with pars plana vitrectomy with an average gain of 7 lines (Snellen in visual acuity (p=0,03. CONCLUSION: In our sample a clear association between AH, ageing and male sex was observed. The majority of patients had unilateral vitreous deposits. Vitrectomy in association with facoemulsification is a safe and effective intervention in this group of patients.

  11. Large Halloween Asteroid at Lunar Distance

    CERN Document Server

    Müller, T G; Butkiewicz-Bąk, M; Duffard, R; Oszkiewicz, D; Käufl, H U; Szakáts, R; Santana-Ros, T; Kiss, C; Santos-Sanz, P

    2016-01-01

    The near-Earth asteroid (NEA) 2015 TB145 had a very close encounter with Earth at 1.3 lunar distances on October 31, 2015. We obtained 3-band mid-infrared observations with the ESO VLT-VISIR instrument and visual lightcurves during the close-encounter phase. The NEA has a (most likely) rotation period of 2.939 +/- 0.005 hours and the visual lightcurve shows a peak-to-peak amplitude of approximately 0.12+/-0.02 mag. We estimate a V-R colour of 0.56+/-0.05 mag from MPC database entries. Applying different phase relations to the available R-/V-band observations produced H_R = 18.6 mag (standard H-G calculations) or H_R = 19.2 mag & H_V = 19.8 mag (via the H-G12 procedure), with large uncertainties of approximately 1 mag. We performed a detailed thermophysical model analysis by using spherical and ellipsoidal shape models. The thermal properties are best explained by an equator-on (+/- ~30 deg) viewing geometry during our measurements with a thermal inertia in the range 250-700 Jm-2s-0.5K-1 (retrograde rotati...

  12. Composition of Rheasilvia Basin on Asteroid Vesta

    Science.gov (United States)

    Ammannito, Eleonora; DeSanctis, Maria Christina; Capaccioni, Fabrizio; Capria, Maria Teresa; Combe, Jean Philippe; Frigeri, Alessandro; Jaumann, Ralf; Longobardo, Andrea; Marchi, Somone; McCord, Thomas B.; McSween, Harry Y., Jr.; Mittlefehldt, David W.; Stephan, Katrin; Tosi, Federico; Raymond, Carol A.; Russell, Christopher T.

    2014-01-01

    The focus of the present study is the compositional analysis of small-scale surface features within the Rheasil-Aa basin on asteroid Vesta. We are using data acquired by the Visible and InfraRed mapping Spectrometer (VIR) on the Dawn mission. Nominal spatial resolution of the data set considered in this study is 70m/px. The portion of Rheasil-Aa basin below 65degS has a howarditic composition, with the higher concentration of diogenitic versus eucritic material in the region between 45deg and 225degE-lon. However, there are several locations, such as craters Tarpeia and Severina and Parentatio Rupes, with lithologic characteristics different from the surroundings regions. Tarpeia crater has a eucritic patch in the west side of the crater, the bottom part ofthe wall and part of the floor. Severina, located in a region of Mg-rich pyroxene, has some diogenitic units on the walls of the crater. Also the Parentatio Rupes has an ob-AOUS diogenitic unit. These units extend for 10-20km, and their location, especially in the case of the two craters, suggests they formed before the cratering events and also before the Rheasil-Aa impact event. The origin of these units is still unclear; however, their characteristics and locations suggests heterogeneity in the composition of the ancient Vestan crust in this particular location of the surface.

  13. Optical spectroscopy and photometry of main-belt asteroids with a high orbital inclination

    Science.gov (United States)

    Iwai, Aya; Itoh, Yoichi; Terai, Tsuyoshi; Gupta, Ranjan; Sen, Asoke; Takahashi, Jun

    2017-02-01

    We carried out low-resolution optical spectroscopy of 51 main-belt asteroids, most of which have highly-inclined orbits. They are selected from D-type candidates in the SDSS-MOC 4 catalog. Using the University of Hawaii 2.2 m telescope and the Inter-University Centre for Astronomy and Astrophysics 2 m telescope in India, we determined the spectral types of 38 asteroids. Among them, eight asteroids were classified as D-type asteroids. Fractions of D-type asteroids are 3.0+/-1.1 for low orbital inclination main-belt asteroids and 7.3+/-2.0 for high orbital inclination main-belt asteroids. The results of our study indicate that some D-type asteroids were formed within the ecliptic region between the main belt and Jupiter, and were then perturbed by Jupiter.

  14. Robotic Asteroid Prospector (RAP) Staged from L-1: Start of the Deep Space Economy Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The objectives of the Robotic Asteroid Prospector (RAP) project are to examine and evaluate the feasibility of asteroid mining in terms of means, methods, and...

  15. The Double Asteroid Redirection Test in the AIDA Mission

    Science.gov (United States)

    Cheng, Andrew; Reed, Cheryl; Rivkin, Andrew

    2016-07-01

    The Asteroid Impact & Deflection Assessment (AIDA) mission will be the first space experiment to demonstrate asteroid impact hazard mitigation by using a kinetic impactor. AIDA is a joint ESA-NASA cooperative project, consisting of the ESA Asteroid Impact Mission (AIM) rendezvous mission and the NASA Double Asteroid Redirection Test (DART) mission. The AIDA target is the near-Earth binary asteroid 65803 Didymos, which will make an unusually close approach to Earth in October, 2022. The DART spacecraft is designed to impact the Didymos secondary at 7 km/s and demonstrate the ability to modify its trajectory through momentum transfer. DART and AIM are currently Phase A studies supported by NASA and ESA respectively. The primary goals of AIDA are (1) perform a full-scale demonstration of the spacecraft kinetic impact technique for deflection of an asteroid; (2) measure the resulting asteroid deflection, by targeting the secondary member of a binary NEO and measuring the resulting changes of the binary orbit; and (3) study hyper-velocity collision effects on an asteroid, validating models for momentum transfer in asteroid impacts based on measured physical properties of the asteroid surface and sub-surface, and including long-term dynamics of impact ejecta. The primary DART objectives are to demonstrate a hyper-velocity impact on the Didymos moon and to determine the resulting deflection from ground-based observations. The DART impact on the Didymos secondary will change the orbital period of the binary which can be measured by supporting Earth-based optical and radar observations. The baseline DART mission launches in December, 2020 to impact the Didymos secondary in September,2022. There are multiple launch opportunities for DART leading to impact around the 2022 Didymos close approach to Earth. The AIM spacecraft will be launched in Dec. 2020 and arrive at Didymos in spring, 2022, several months before the DART impact. AIM will characterize the Didymos binary system

  16. Polarimetric survey of main-belt asteroids. V. The unusual polarimetric behavior of V-type asteroids

    Science.gov (United States)

    Gil-Hutton, R.; López-Sisterna, C.; Calandra, M. F.

    2017-03-01

    Aims: We present the results of a polarimetric survey of main-belt asteroids at Complejo Astronómico El Leoncito (CASLEO), San Juan, Argentina. The aims of this survey are to increase the database of asteroid polarimetry, to estimate diversity in polarimetric properties of asteroids that belong to different taxonomic classes, and to search for objects that exhibit anomalous polarimetric properties. Methods: The data were obtained using the CASPROF and CASPOL polarimeters at the 2.15 m telescope. The CASPROF polarimeter is a two-hole aperture polarimeter with rapid modulation and CASPOL is a polarimeter based on a CCD detector, which allows us to observe fainter objects with better signal-to-noise ratio. Results: The survey began in 1995 and data on a large sample of asteroids were obtained until 2012. A second period began in 2013 using a polarimeter with a more sensitive detector in order to study small asteroids, families, and special taxonomic groups. We obtained 55 polarimetric measurements for 28 V-type main belt asteroids, all of them polarimetrically observed for the first time. The data obtained in this survey let us find polarimetric parameters for (1459) Magnya and for a group of 11 small V-type objects with similar polarimetric behavior. These polarization curves are unusual since they show a shallow minimum and a small inversion angle in comparison with (4) Vesta, although they have a steeper slope at α0. This polarimetric behavior could be explained by differences in the regoliths of these asteroids. The observations of (2579) Spartacus, and perhaps also (3944) Halliday, indicate a inversion angle larger than 24-25°. Based on observations carried out at the Complejo Astronómico El Leoncito, operated under agreement between the Consejo Nacional de Investigaciones Científicas y Técnicas de la República Argentina and the National Universities of La Plata, Córdoba, and San Juan.

  17. Driving Mechanism of the Brazil Nut Effect in Asteroids

    Science.gov (United States)

    Perera, Viranga; Jackson, Alan P.; Asphaug, Erik; Ballouz, Ronald

    2016-10-01

    Asteroids are remnant objects from the early planet formation process. Most asteroids are considered rubble-piles since they are likely conglomerates of smaller objects held together by gravity and possibly cohesion. Due to that particular structure, asteroids may be studied using techniques of granular flow. One particular effect called the Brazil Nut Effect (BNE) has previously been proposed to be relevant to asteroids. This effect entails the size-sorting of particles when shaken, where larger particles migrate against the direction of gravity while the smaller particles migrate towards the direction of gravity. Analysis of data from the Hayabusa mission led to asteroid 25143 Itokawa being considered an example where the BNE has occurred bringing large boulders to its surface. Since spacecraft data are limited due to the cost of space missions, there are two other methods of studying this effect: experiments and computer simulations. Though experiments have been done under terrestrial gravity and in low-gravity conditions on parabolic flights, experimental setups cannot fully model the BNE for three-dimensional, self-gravitating, conglomerate objects such as asteroids. Computer simulations have been done in low-gravity conditions utilizing rectangular and cylindrical box configurations and recently in a spherical configuration of particles. Most works have focused on using one large particle embedded with smaller particles (i.e. the intruder model). This has been due to the simplicity and the lack of detailed knowledge about the interior of asteroids. However, in this work we show that the intruder BNE, though important in a wider granular flow context, is not relevant to asteroids. We have run BNE simulations for one, two, and three intruders in a spherical configuration of particles and we find that unless the intruder starts off near the surface of our simulated aggregates they generally do not rise to the surface. This contrasts with a bimodal population of

  18. The Double Asteroid Redirection Test (DART) for the AIDA Mission

    Science.gov (United States)

    Stickle, Angela; Cheng, Andy F.; Michel, Patrick; Barnouin, Olivier S.; Campo Bagatin, Adriano; Miller, Paul L.; Pravec, Petr; Richardson, Derek C.; Schwartz, Stephen R.; Tsiganis, Kleomenis; Ulamec, Stephan; AIDA Impact Modeling and Simulation Working Group

    2016-10-01

    The Asteroid Impact Deflection Assessment (AIDA) mission will be the first space experiment to demonstrate asteroid impact hazard mitigation using a kinetic impactor. AIDA is a joint ESA-NASA cooperative project, consisting of the NASA Double Asteroid Redirection Test (DART) mission, which provides the kinetic impactor, and the ESA Asteroid Impact Mission (AIM) rendezvous spacecraft. DART is a Phase A study supported by NASA, and AIM is a Phase B1 study supported by ESA. The AIDA target is the near-Earth binary asteroid 65803 Didymos, which will make a close approach to Earth in October, 2022. The DART spacecraft is designed to impact the Didymos secondary at ~6 km/s and deflect its trajectory, changing the orbital period of the binary. This change can be measured by Earth-based optical and radar observations. The primary goals of AIDA are to (1) perform a full-scale demonstration of asteroid deflection by kinetic impact; (2) measure the resulting deflection; and (3) validate and improve models for momentum transfer in high-speed impacts on an asteroid. The combined DART and AIM missions will provide the first measurements of momentum transfer efficiency from a kinetic impact at full scale on an asteroid, where the impact conditions of the projectile are known, and physical properties and internal structures of the target asteroid are also characterized. In addition to a predicted 4.4 minute change in the binary orbit period, assuming unit momentum transfer efficiency, the DART kinetic impact is predicted to induce forced librations of the Didymos secondary of possibly several degrees amplitude. Models predict the impact will create a 6-17 meter diameter crater, depending on target physical properties, and it will release a volume of particulate ejecta that may be directly observable from Earth or even resolvable as a coma or an ejecta tail by ground-based telescopes. Current simulations of the DART impact provide predictions for momentum transfer, crater size, and

  19. Hungaria Asteroid Family as the Source of Aubrite Meteorites

    CERN Document Server

    Ćuk, Matija; Nesvorný, David

    2014-01-01

    The Hungaria asteroids are interior to the main asteroid belt, with semimajor axes between 1.8 and 2 AU, low eccentricities and inclinations of 16-35 degrees. Small asteroids in the Hungaria region are dominated by a collisional family associated with (434) Hungaria. The dominant spectral type of the Hungaria group is the E or X-type (Warner et al, 2009), mostly due to the E-type composition of Hungaria and its genetic family. It is widely believed the E-type asteroids are related to the aubrite meteorites, also known as enstatite achondrites (Gaffey et al, 1992). Here we explore the hypothesis that aubrites originate in the Hungaria family. In order to test this connection, we compare model Cosmic Ray Exposure ages from orbital integrations of model meteoroids with those of aubrites. We show that long CRE ages of aubrites (longest among stony meteorite groups) reflect the delivery route of meteoroids from Hungarias to Earth being different than those from main-belt asteroids. We find that the meteoroids from...

  20. Hayabusa2 Sampler: Collection of Asteroidal Surface Material

    Science.gov (United States)

    Sawada, Hirotaka; Okazaki, Ryuji; Tachibana, Shogo; Sakamoto, Kanako; Takano, Yoshinori; Okamoto, Chisato; Yano, Hajime; Miura, Yayoi; Abe, Masanao; Hasegawa, Sunao; Noguchi, Takaaki

    2017-02-01

    Japan Aerospace Exploration Agency (JAXA) launched the asteroid exploration probe "Hayabusa2" in December 3rd, 2014, following the 1st Hayabusa mission. With technological and scientific improvements from the Hayabusa probe, we plan to visit the C-type asteroid 162137 Ryugu (1999 JU3), and to sample surface materials of the C-type asteroid that is likely to be different from the S-type asteroid Itokawa and contain more pristine materials, including organic matter and/or hydrated minerals, than S-type asteroids. We developed the Hayabusa2 sampler to collect a minimum of 100 mg of surface samples including several mm-sized particles at three surface locations without any severe terrestrial contamination. The basic configuration of the sampler design is mainly as same as the 1st Hayabusa (Yano et al. in Science, 312(5778):1350-1353, 2006), with several minor but important modifications based on lessons learned from the Hayabusa to fulfill the scientific requirements and to raise the scientific value of the returned samples. In this paper, we will report the details of the sampling system of Hayabusa2 with results of performance tests during the development and the current status of the sampling system.

  1. Spins of Asteroids: The tale of the long tail

    CERN Document Server

    Steinberg, Elad

    2014-01-01

    The Asteroid Belt and the Kuiper Belt are relics from the formation of our solar system. Understanding the size and spin distribution of the two belts is crucial for a deeper understanding of the formation of our solar system and the dynamical process that govern it. In this paper, we investigate the effect of collisions on the evolution of the spin distribution of asteroids and KBO's. We find that the power law nature of the impactors' size distribution leads to a L\\'evy distribution of the spin rates. This results in a power law tail of the spin distribution, in stark contrast to the usually quoted Maxwellian distribution. We show that for bodies larger than 10 km, collisions alone lead to spin rates peaking at 0.15-0.5 revolutions per day. Comparing that to the observed spin rates of large asteroids ($R>50$ km), we find that the spins of large asteroids, peaking at $\\sim1-2$ revolutions per day, are dominated by a primordial component that reflects the formation mechanism of the asteroids. Similarly, the K...

  2. Target selection and transfer trajectories design for exploring asteroid mission

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Technique of target selection and profiles of transfer trajectory for Chinese asteroid exploring mission are studied systemically.A complete set of approaches to selecting mission targets and designing the transfer trajectory is proposed.First,when selecting a target for mission,some factors regarded as the scientific motivations are discussed.Then,when analyzing the accessibility of targets,instead of the classical strategy,the multiple gravity-assist strategy is provided.The suitable and possible targets,taking into account scientific value and technically feasible,are obtained via selection and estimation.When designing the transfer trajectory for exploring asteroid mission,an approach to selecting gravity-assist celestial body is proposed.Finally,according to the mission constraints,the trajectory profile with 2-years △V-EGA for exploring asteroid is presented.Through analyzing the trajectory profile,unexpected result that the trajectory would pass by two main-belts asteroids is found.So,the original proposal is extended to the multiple flybys mission.It adds the scientific return for asteroid mission.

  3. A retrograde co-orbital asteroid of Jupiter.

    Science.gov (United States)

    Wiegert, Paul; Connors, Martin; Veillet, Christian

    2017-03-29

    Recent theoretical work in celestial mechanics has revealed that an asteroid may orbit stably in the same region as a planet, despite revolving around the Sun in the sense opposite to that of the planet itself. Asteroid 2015 BZ509 was discovered in 2015, but with too much uncertainty in its measured orbit to establish whether it was such a retrograde co-orbital body. Here we report observations and analysis that demonstrates that asteroid 2015 BZ509 is indeed a retrograde co-orbital asteroid of the planet Jupiter. We find that 2015 BZ509 has long-term stability, having been in its current, resonant state for around a million years. This is long enough to preclude precise calculation of the time or mechanism of its injection to its present state, but it may be a Halley-family comet that entered the resonance through an interaction with Saturn. Retrograde co-orbital asteroids of Jupiter and other planets may be more common than previously expected.

  4. Testing the inversion of Gaia photometry of asteroids

    Science.gov (United States)

    Santana-Ros, Toni; Bartczak, Przemysław; Michałowski, Tadeusz; Tanga, Paolo; Cellino, Alberto

    2016-06-01

    We studied the performance of the Gaia inversion algorithm under different scenarios. The test consisted of feeding the algorithm with several sets of photometric simulations for ten thousand asteroids having different spin axis orientations, rotational periods and shapes, including binaries. We used the Gaia mission simulator to generate the observational epochs, while the brightnesses were generated using a Z-buffer standard graphic method. It was found that results are biased against asteroids presenting low lightcurve amplitude and low pole latitudes. The analysis of the inversion results led to the confirmation that synchronous binary systems can be successfully modelled with a simple triaxial ellipsoid body. On the basis of these simulations, it was also possible to develop strategies for binary asteroid detection. The presented quantitative results include the semi-major axis values of the triaxial ellipsoid model with a high probability of hosting binary systems. We also present the Gaia-Groundbased Observation Service for Asteroids (Gaia-GOSA), which aims to support ground-based observation campaigns of asteroids.

  5. Simulations of directed energy thrust on rotating asteroids

    Science.gov (United States)

    Griswold, Janelle; Madajian, Jonathan; Johansson, Isabella; Pfau, Krysten; Lubin, Philip; Hughes, Gary B.; Gilkes, Aidan; Meinhold, Peter; Motta, Caio; Brashears, Travis; Zhang, Qicheng

    2015-09-01

    Asteroids that threaten Earth could be deflected from their orbits using directed energy to vaporize the surface, because the ejected plume creates a reaction thrust that alters the asteroid's trajectory. One concern regarding directed energy deflection is the rotation of the asteroid, as this will reduce the average thrust magnitude and modify the thrust direction. Flux levels required to evaporate surface material depend on surface material composition and albedo, thermal, and bulk mechanical properties of the asteroid, and rotation rate. The observed distribution of asteroid rotation rates is used, along with an estimated range of material and mechanical properties, as input to a 3D thermal-physical model to calculate the resultant thrust vector. The model uses a directed energy beam, striking the surface of a rotating sphere with specified material properties, beam profile, and rotation rate. The model calculates thermal changes in the sphere, including vaporization and mass ejection of the target material. The amount of vaporization is used to determine a thrust magnitude that is normal to the surface at each point on the sphere. As the object rotates beneath the beam, vaporization decreases, as the temperature drops and causes both a phase shift and magnitude decrease in the average thrust vector. A surface integral is calculated to determine the thrust vector, at each point in time, producing a 4D analytical model of the expected thrust profile for rotating objects.

  6. Identification and Calculation of the Three-Dimensional Orbit of an Asteroid

    Science.gov (United States)

    Pereira, Vincent; Millan, Justin; Martin, Emerick

    2013-01-01

    Asteroids are clumps of rock, the sizes of which range from less than a kilometer to a few hundred kilometers in diameter. They are generally found in the unusually large gap between Mars and Jupiter. There are probably more than 40,000 asteroids in this gap called the "asteroid belt." In this paper we describe our efforts in confirming…

  7. The Asteroid Impact Mission (AIM): Studying the geophysics of small binaries, measuring asteroid deflection and studying impact physics

    Science.gov (United States)

    Kueppers, Michael; Michel, Patrick; AIM Team

    2016-10-01

    Binary asteroids and their formation mechanisms are of particular interest for understanding the evolution of the small bodies in the solar system. Also, hazards to Earth from impact of near-Earth asteroids and their mitigation have drawn considerable interest over the last decades.Those subjects are both addressed by ESA's Asteroid Impact mission, which is part of the Asteroid Impact & Deflection Assessment (AIDA) currently under study in collaboration between NASA and ESA. NASA's DART mission will impact a projectile into the minor component of the binary near-Earth asteroid (65803) Didymos in 2022. The basic idea is to demonstrate the effect of the impact on the orbital period of the secondary around the primary. ESA's AIM will monitor the Didymos system for several months around the DART impact time.AIM will be launched in aurumn 2020. It is foreseen to arrive at Didymos in April 2022. The mission takes advantage of a close approach of Didymos to Earth. The next opportunity would arise in 2040 only.AIM will stay near Didymos for approximately 6 months. Most of the time it will be placed on the illuminated side of the system, at distances of approximately 35 km and 10 km. AIM is expected to move away from Didymos for some time around the DART impact.The reference payload for AIM includes two visual imagers, a hyperspectral camera, a lidar, a thermal infrared imager, a monostatic high frequency radar, and a bistatic low frequency radar. In addition, AIM will deploy a small lander on the secondary asteroid, and two cubesats that will be used for additional, more risky investigations close to or on the surface of the asteroid.Major contributions from AIM are expected in the study of the geophysics of small asteroids (including for the first time, radar measurements of an interior structure), the formation of binary asteroids, the momentum enhancement factor from the DART impact (through measuring the mass and the change of orbit of the seondary), and impact physics

  8. Chelyabinsk meteorite explains unusual spectral properties of Baptistina Asteroid Family

    CERN Document Server

    Reddy, Vishnu; Bottke, William; Cloutis, Ed; Izawa, Matt; O'Brien, Dave; Mann, Paul; Cuddy, Matt; Corre, Lucille Le; Gaffey, Michael; Fujihara, Gary

    2014-01-01

    We investigated the spectral and compositional properties of Chelyabinsk meteorite to identify its possible parent body in the main asteroid belt. Our analysis shows that the meteorite contains two spectrally distinct but compositionally indistinguishable components of LL5 chondrite and shock blackened/impact melt material. Our X-ray diffraction analysis confirms that the two lithologies of the Chelyabinsk meteorite are extremely similar in modal mineralogy. The meteorite is compositionally similar to LL chondrite and its most probable parent asteroid in the main belt is a member of the Flora family. Intimate mixture of LL5 chondrite and shock blackened/impact melt material from Chelyabinsk provides a spectral match with (8) Flora, the largest asteroid in the Flora family. The Baptistina family and Flora family overlap each other in dynamical space. Mineralogical analysis of (298) Baptistina and 9 small family members shows that their surface compositions are similar to LL chondrites, although their absorptio...

  9. Observed Asteroid Surface Area in the Thermal Infrared

    Science.gov (United States)

    Nugent, C. R.; Mainzer, A.; Masiero, J.; Wright, E. L.; Bauer, J.; Grav, T.; Kramer, E.; Sonnett, S.

    2017-02-01

    The rapid accumulation of thermal infrared observations and shape models of asteroids has led to increased interest in thermophysical modeling. Most of these infrared observations are unresolved. We consider what fraction of an asteroid’s surface area contributes the bulk of the emitted thermal flux for two model asteroids of different shapes over a range of thermal parameters. The resulting observed surface in the infrared is generally more fragmented than the area observed in visible wavelengths, indicating high sensitivity to shape. For objects with low values of the thermal parameter, small fractions of the surface contribute the majority of thermally emitted flux. Calculating observed areas could enable the production of spatially resolved thermal inertia maps from non-resolved observations of asteroids.

  10. On the oldest asteroid families in the main belt

    CERN Document Server

    Carruba, V; Aljbaae, S; Domingos, R C; Huaman, M

    2016-01-01

    Asteroid families are groups of minor bodies produced by high-velocity collisions. After the initial dispersions of the parent bodies fragments, their orbits evolve because of several gravitational and non-gravitational effects,such as diffusion in mean-motion resonances, Yarkovsky and YORP effects, close encounters of collisions, etc. The subsequent dynamical evolution of asteroid family members may cause some of the original fragments to travel beyond the conventional limits of the asteroid family. Eventually, the whole family will dynamically disperse and no longer be recognizable. A natural question that may arise concerns the timescales for dispersion of large families. In particular, what is the oldest still recognizable family in the main belt? Are there any families that may date from the late stages of the Late Heavy Bombardment and that could provide clues on our understanding of the primitive Solar System? In this work, we investigate the dynamical stability of seven of the allegedly oldest familie...

  11. NEOWISE Reactivation Mission Year Two: Asteroid Diameters and Albedos

    CERN Document Server

    Nugent, C R; Bauer, J; Cutri, R M; Kramer, E A; Grav, T; Masiero, J; Sonnett, S; Wright, E L

    2016-01-01

    The Near-Earth Object Wide-Field Infrared Survey Explorer (NEOWISE) mission continues to detect, track, and characterize minor planets. We present diameters and albedos calculated from observations taken during the second year since the spacecraft was reactivated in late 2013. These include 207 near-Earth asteroids and 8,885 other asteroids. $84\\%$ of the near-Earth asteroids did not have previously measured diameters and albedos by the NEOWISE mission. Comparison of sizes and albedos calculated from NEOWISE measurements with those measured by occultations, spacecraft, and radar-derived shapes shows accuracy consistent with previous NEOWISE publications. Diameters and albedos fall within $ \\pm \\sim20\\%$ and $\\pm\\sim40\\%$, 1-sigma, respectively, of those measured by these alternate techniques. NEOWISE continues to preferentially discover near-Earth objects which are large ($>100$ m), and have low albedos.

  12. VLBI Radar of the 2012 DA14 Asteroid

    Science.gov (United States)

    Nechaeva, M. B.; Dugin, N. A.; Antipenko, A. A.; Bezrukov, D. A.; Bezrukov, V. V.; Voytyuk, V. V.; Dement'ev, A. F.; Jekabsons, N.; Klapers, M.; Konovalenko, A. A.; Kulishenko, V. F.; Nabatov, A. S.; Nesteruk, V. N.; Putillo, D.; Reznichenko, A. M.; Salerno, E.; Snegirev, S. D.; Tikhomirov, Yu. V.; Khutornoy, R. V.; Skirmante, K.; Shmeld, I.; Chagunin, A. K.

    2015-03-01

    An experiment on VLBI radar of the 2012 DA14 asteroid was carried out on February 15-16, 2011 at the time of its closest approach to the Earth. The research teams of Kharkov (Institute of Radio Astronomy of the National Academy of Sciences of Ukraine), Evpatoria (National Space Facilities Control and Test Center), Nizhny Novgorod (Radiophysical Research Institute), Bologna (Istituto di Radioastronomia (INAF)), and Ventspils (Ventspils International Radioastronomy Center) took part in the experiment. The asteroid was irradiated by the RT-70 planetary radar (Evpatoria) at a frequency of 5 GHz. The reflected signal was received using two 32-m radio telescopes in Medicina (Italy) and Irbene (Latvia) in radiointerferometric mode. The Doppler frequency shifts in bi-static radar mode and interference frequency in VLBI mode were measured. Accuracy of the VLBI radar method for determining the radial and angular velocities of the asteroid were estimated.

  13. Improved Asteroid Astrometry and Photometry with Trail Fitting

    CERN Document Server

    Vereš, Peter; Denneau, Larry; Wainscoat, Richard; Holman, Matthew J; Lin, Hsing-Wen

    2012-01-01

    Asteroid detections in astronomical images may appear as trails due to a combination of their apparent rate of motion and exposure duration. Nearby asteroids in particular typically have high apparent rates of motion and acceleration. Their recovery, especially on their discovery apparition, depends upon obtaining good astrometry from the trailed detections. We present an analytic function describing a trailed detection under the assumption of a Gaussian point spread function (PSF) and constant rate of motion. We have fit the function to both synthetic and real trailed asteroid detections from the Pan-STARRS1 survey telescope to obtain accurate astrometry and photometry. For short trails our trailing function yields the same astrometric and photometry accuracy as a functionally simpler 2-d Gaussian but the latter underestimates the length of the trail - a parameter that can be important for measuring the object's rate of motion and assessing its cometary activity. For trails longer than about 10 pixels (> 3xP...

  14. Automatic detection of asteroids and meteoroids. A Wide Field Survey

    Science.gov (United States)

    Vereš, P.; Tóth, J.; Jedicke, R.; Tonry, J.; Denneau, L.; Wainscoat, R.; Kornoš, L.; Šilha, J.

    2014-07-01

    We propose a low-cost robotic optical survey aimed at 1-300 m Near Earth Objects (NEO) based on four state-of-the-art telescopes having extremely wide field of view. The small Near-Earth Asteroids (NEA) represent a potential risk but also easily accessible space resources for future robotic or human space in-situ exploration, or commercial activities. The survey system will be optimized for the detection of fast moving-trailed-asteroids, space debris and will provide real-time alert notifications. The expected cost of the system including 1-year development and 2-year operation is 1,000,000 EUR. The successful demonstration of the system will promote cost-effectiveicient ADAM-WFS (Automatic Detection of Asteroids and Meteoroids -- A Wide Field Survey) systems to be built around the world.

  15. Near-field effects of asteroid impacts in deep water

    Energy Technology Data Exchange (ETDEWEB)

    Gisler, Galen R [Los Alamos National Laboratory; Weaver, Robert P [Los Alamos National Laboratory; Gittings, Michael L [Los Alamos National Laboratory

    2009-06-11

    Our previous work has shown that ocean impacts of asteroids below 500 m in diameter do not produce devastating long-distance tsunamis. Nevertheless, a significant portion of the ocean lies close enough to land that near-field effects may prove to be the greatest danger from asteroid impacts in the ocean. Crown splashes and central jets that rise up many kilometres into the atmosphere can produce, upon their collapse, highly non-linear breaking waves that could devastate shorelines within a hundred kilometres of the impact site. We present illustrative calculations, in two and three dimensions, of such impacts for a range of asteroid sizes and impact angles. We find that, as for land impacts, the greatest dangers from oceanic impacts are the short-term near-field, and long-term atmospheric effects.

  16. The violent collisional history of asteroid 4 Vesta.

    Science.gov (United States)

    Marchi, S; McSween, H Y; O'Brien, D P; Schenk, P; De Sanctis, M C; Gaskell, R; Jaumann, R; Mottola, S; Preusker, F; Raymond, C A; Roatsch, T; Russell, C T

    2012-05-11

    Vesta is a large differentiated rocky body in the main asteroid belt that accreted within the first few million years after the formation of the earliest solar system solids. The Dawn spacecraft extensively imaged Vesta's surface, revealing a collision-dominated history. Results show that Vesta's cratering record has a strong north-south dichotomy. Vesta's northern heavily cratered terrains retain much of their earliest history. The southern hemisphere was reset, however, by two major collisions in more recent times. We estimate that the youngest of these impact structures, about 500 kilometers across, formed about 1 billion years ago, in agreement with estimates of Vesta asteroid family age based on dynamical and collisional constraints, supporting the notion that the Vesta asteroid family was formed during this event.

  17. Automatic Detection of Asteroids and Meteoroids - A Wide Field Survey

    CERN Document Server

    Vereš, P; Jedicke, R; Tonry, J; Denneau, L; Wainscoat, R; Kornoš, L; Šilha, J

    2014-01-01

    We propose a low-cost robotic optical survey aimed at $1-300$ m Near Earth Objects (NEO) based on four state-of-the-art telescopes having extremely wide field of view. The small Near-Earth Asteroids (NEA) represent a potential risk but also easily accessible space resources for future robotic or human space in-situ exploration, or commercial activities. The survey system will be optimized for the detection of fast moving - trailed - asteroids, space debris and will provide real-time alert notifications. The expected cost of the system including 1-year development and 2-year operation is 1,000,000 EUR. The successful demonstration of the system will promote cost-efficient ADAM-WFS (Automatic Detection of Asteroids and Meteoroids - A Wide Field Survey) systems to be built around the world.

  18. Accretion of jet streams and formation of asteroids

    Science.gov (United States)

    Hu, Zhong-wei; Tong, Yi

    1983-03-01

    Our basic view on the formation of asteroids, stated in [1], is that the initial physical and chemical conditions in the asteroid region led to a slow growth of planetesimals in the region and a transfer of accretable matter to the Jupitor region, resulting in the planetesimals stopping at the "half-finished" stage, eventually forming only asteroids and not major planets. In this paper, using the conditions of the nebular disk obtained in that paper and the formula for gravitational instability and regarding the rings resulting from gravitational instability as "jet streams", we apply the theory of accretion of jet streams to calculate the growth of the planetesimals and discuss the question of the transfer of accretable material, providing further confirmation of our basic view.

  19. Flight status of robotic asteroid sample return mission Hayabusa2

    Science.gov (United States)

    Tsuda, Yuichi; Nakazawa, Satoru; Kushiki, Kenichi; Yoshikawa, Makoto; Kuninaka, Hitoshi; Watanabe, Seiichiro

    2016-10-01

    The Japan Aerospace Exploration Agency launched the asteroid sample return spacecraft "Hayabusa2" on December 3, 2014. Hayabusa2 will reach the C-type asteroid 1999 JU3 in 2018, and return back to the Earth in 2020. Sample collections from three sites, four surface rovers deployment and a 4 MJ-class kinetic impact crater generation are planned in the 1.5 years of the asteroid-proximity operation. The mission objective of Hayabusa2 has three aspects, science, engineering and exploration, all of which would be expanded by the successful round-trip journey. This paper describes the outline of the Hayabusa2 mission and the current flight status after the seven month of the interplanetary cruise.

  20. Asteroid-Comet Continuum Objects in the Solar System

    CERN Document Server

    Hsieh, Henry H

    2016-01-01

    In this review presented at the Royal Society meeting, "Cometary Science After Rosetta", I present an overview of studies of small solar system objects that exhibit properties of both asteroids and comets (with a focus on so-called active asteroids). Sometimes referred to as "transition objects", these bodies are perhaps more appropriately described as "continuum objects", to reflect the notion that rather than necessarily representing actual transitional evolutionary states between asteroids and comets, they simply belong to the general population of small solar system bodies that happen to exhibit a continuous range of observational, physical, and dynamical properties. Continuum objects are intriguing because they possess many of the properties that make classical comets interesting to study (e.g., relatively primitive compositions, ejection of surface and subsurface material into space where it can be more easily studied, and orbital properties that allow us to sample material from distant parts of the sol...

  1. Galileo Photometry of Asteroid 951 Gaspra

    Science.gov (United States)

    Helfenstein, P.; Veverka, J.; Thomas, P.C.; Simonelli, D.P.; Lee, P.; Klaasen, K.; Johnson, T.V.; Breneman, H.; Head, J.W.; Murchie, S.; Fanale, F.; Robinson, M.; Clark, B.; Granahan, J.; Garbeil, H.; McEwen, A.S.; Kirk, R.L.; Davies, M.; Neukum, G.; Mottola, S.; Wagner, R.; Belton, M.; Chapman, C.; Pilcher, C.

    1994-01-01

    Galileo images of Gaspra make it possible for the first time to determine a main-belt asteroid's photometric properties accurately by providing surface-resolved coverage over a wide range of incidence and emission angles and by extending the phase angle coverage to phases not observable from Earth. We combine Earth-based telescopic photometry over phase angles 2?? ??? ?? ??? 25?? with Galileo whole-disk and disk-resolved data at 33?? ??? ?? ??? 51?? to derive average global photometric properties in terms of Hapke's photometric model. The microscopic texture and particle phase-function behavior of Gaspra's surface are remarkably like those of other airless rocky bodies such as the Moon. The macroscopic surface roughness parameter, ??̄ = 29??, is slightly larger than that reported for typical lunar materials. The particle single scattering albedo, ??́0 = 0.36 ?? 0.07, is significantly larger than for lunar materials, and the opposition surge amplitude, B0 = 1.63 ?? 0.07, is correspondingly smaller. We determine a visual geometric albedo pv = 0.22 ?? 0.06 for Gaspra, in close agreement with pv = 0.22 ?? 0.03 estimated from Earth-based observations. Gaspra's phase integral is 0.47, and the bolometric Bond albedo is estimated to be 0.12 ?? 0.03. An albedo map derived by correcting Galileo images with our average global photometric function reveals subdued albedo contrasts of ??10% or less over Gaspra's northern hemisphere. Several independent classification algorithms confirm the subtle spectral heterogeneity reported earlier (S. Mottola, M. DiMartino, M. Gonano-Beurer, H. Hoffman, and G. Neukum, 1993, Asteroids, Comets, Meteors, pp. 421-424; M. J. S. Belton et al., 1992, Science 257, 1647-1652). Whole-disk colors (0.41 ??? ?? ??? 0.99 ??m) vary systematically with longitude by about ??5%, but color differences as large as 30% occur locally. Colors vary continuously between end-member materials whose areal distribution correlates with regional topography. Infrared

  2. The Complex History of Trojan Asteroids

    Science.gov (United States)

    Emery, J. P.; Marzari, F.; Morbidelli, A.; French, L. M.; Grav, T.

    The Trojan asteroids, orbiting the Sun in Jupiter's stable Lagrange points, provide a unique perspective on the history of our solar system. As a large population of small bodies, they record important gravitational interactions in the dynamical evolution of the solar system. As primitive bodies, their compositions and physical properties provide windows into the conditions in the solar nebula in the region in which they formed. In the past decade, significant advances have been made in understanding their physical properties, and there has been a revolution in thinking about the origin of Trojans. The ice and organics generally presumed to be a significant part of Trojan composition have yet to be detected directly, although the low density of the binary system Patroclus (and possibly low density of the binary/moonlet system Hektor) is consistent with an interior ice component. By contrast, fine-grained silicates that appear to be similar to cometary silicates in composition have been detected, and a color bimodality may indicate distinct compositional groups among the Trojans. Whereas Trojans had traditionally been thought to have formed near 5 AU, a new paradigm has developed in which the Trojans formed in the proto-Kuiper belt, and were scattered inward and captured in the Trojan swarms as a result of resonant interactions of the giant planets. Whereas the orbital and population distributions of current Trojans are consistent with this origin scenario, there are significant differences between current physical properties of Trojans and those of Kuiper belt objects. These differences may be indicative of surface modification due to the inward migration of objects that became the Trojans, but understanding of appropriate modification mechanisms is poor and would benefit from additional laboratory studies. Many open questions about this intriguing population remain, and the future promises significant strides in our understanding of Trojans. The time is ripe for a

  3. M4AST - A Tool for Asteroid Modelling

    Science.gov (United States)

    Birlan, Mirel; Popescu, Marcel; Irimiea, Lucian; Binzel, Richard

    2016-10-01

    M4AST (Modelling for asteroids) is an online tool devoted to the analysis and interpretation of reflection spectra of asteroids in the visible and near-infrared spectral intervals. It consists into a spectral database of individual objects and a set of routines for analysis which address scientific aspects such as: taxonomy, curve matching with laboratory spectra, space weathering models, and mineralogical diagnosis. Spectral data were obtained using groundbased facilities; part of these data are precompiled from the literature[1].The database is composed by permanent and temporary files. Each permanent file contains a header and two or three columns (wavelength, spectral reflectance, and the error on spectral reflectance). Temporary files can be uploaded anonymously, and are purged for the property of submitted data. The computing routines are organized in order to accomplish several scientific objectives: visualize spectra, compute the asteroid taxonomic class, compare an asteroid spectrum with similar spectra of meteorites, and computing mineralogical parameters. One facility of using the Virtual Observatory protocols was also developed.A new version of the service was released in June 2016. This new release of M4AST contains a database and facilities to model more than 6,000 spectra of asteroids. A new web-interface was designed. This development allows new functionalities into a user-friendly environment. A bridge system of access and exploiting the database SMASS-MIT (http://smass.mit.edu) allows the treatment and analysis of these data in the framework of M4AST environment.Reference:[1] M. Popescu, M. Birlan, and D.A. Nedelcu, "Modeling of asteroids: M4AST," Astronomy & Astrophysics 544, EDP Sciences, pp. A130, 2012.

  4. Amor: Investigating The Triple Asteroid System 2001 SN263

    Science.gov (United States)

    Jones, T.; Bellerose, Julie; Lee, P.; Prettyman, T.; Lawrence, D.; Smith, P.; Gaffey, M.; Nolan, M.; Goldsten, J.; Thomas, P.; Veverka, J.; Farquhar, R.; Heldmann, J.; Reddy, V.; Williams, B.; Chartres, J.; DeRosee, R.; Dunham, D.

    2010-10-01

    The Amor mission will rendezvous and land at the triple Near-Earth Asteroid system (153591) 2001 SN263 and execute detailed, in-situ science investigations. The spacecraft reaches 2001 SN263 by using a two-year ΔVEGA (ΔV-Earth Gravity Assist) trajectory with a relatively low launch C3 of 33.5 km2/s2. Rendezvous will enable reconnaissance activities including global and regional imaging, shape modeling, system dynamics, and compositional mapping. After landing, Amor will conduct in-situ imaging (panoramic to microscopic scale) and compositional measurements to include elemental abundance. The main objectives are to 1) establish in-situ the long-hypothesized link between C-type asteroids and the primitive carbonaceous chondrite (CC) meteorites, 2) investigate the nature, origin and evolution of C-type asteroids, and 3) investigate the origin and evolution of a multiple asteroid system. The mission also addresses the distribution of volatiles and organic materials, impact hazards, and resources for future exploration. Amor is managed by NASA Ames Research Center in partnership with Orbital Sciences, KinetX, MDA, and Draper with heritage instruments provided by Ball Aerospace, JHU/APL, and Firestar Engineering. The science team brings experience from NEAR, Hayabusa, Deep Impact, Dawn, LCROSS, Kepler, and Mars missions. In this paper, we describe the science, mission design, and main operational challenges of performing in-situ science at this triple asteroid system. Challenges include landing on the asteroid components, thermal environment, short day-night cycles, and the operation of deployed instruments in a low gravity (10^-5 g) environment.

  5. Hungaria asteroid family as the source of aubrite meteorites

    Science.gov (United States)

    Ćuk, Matija; Gladman, Brett J.; Nesvorný, David

    2014-09-01

    The Hungaria asteroids are interior to the main asteroid belt, with semimajor axes between 1.8 and 2 AU, low eccentricities and inclinations of 16-35°. Small asteroids in the Hungaria region are dominated by a collisional family associated with (434) Hungaria. The dominant spectral type of the Hungaria group is the E or X-type (Warner et al. [2009]. Icarus, 204, 172-182), mostly due to the E-type composition of Hungaria and its genetic family. It is widely believed the E-type asteroids are related to the aubrite meteorites, also known as enstatite achondrites (Gaffey et al. [1992]. Icarus, 100, 95-109). Here we explore the hypothesis that aubrites originate in the Hungaria family. In order to test this connection, we compare model Cosmic Ray Exposure ages from orbital integrations of model meteoroids with those of aubrites. We show that long CRE ages of aubrites (longest among stony meteorite groups) reflect the delivery route of meteoroids from Hungarias to Earth being different than those from main-belt asteroids. We find that the meteoroids from Hungarias predominantly reach Earth by Yarkovsky-drifting across the orbit of Mars, with no assistance from orbital resonances. We conclude that the CRE ages of aubrites are fully consistent with a dominant source at the inner boundary of the Hungaria family at 1.7 AU. From here, meteoroids reach Earth through the Mars-crossing region, with relatively quick delivery times favored due to collisions (with Hungarias and the inner main-belt objects). We find that, after Vesta, (434) Hungaria is the best candidate for an asteroidal source of an achondrite group.

  6. NASA's asteroid redirect mission: Robotic boulder capture option

    Science.gov (United States)

    Abell, P.; Nuth, J.; Mazanek, D.; Merrill, R.; Reeves, D.; Naasz, B.

    2014-07-01

    NASA is examining two options for the Asteroid Redirect Mission (ARM), which will return asteroid material to a Lunar Distant Retrograde Orbit (LDRO) using a robotic solar-electric-propulsion spacecraft, called the Asteroid Redirect Vehicle (ARV). Once the ARV places the asteroid material into the LDRO, a piloted mission will rendezvous and dock with the ARV. After docking, astronauts will conduct two extravehicular activities (EVAs) to inspect and sample the asteroid material before returning to Earth. One option involves capturing an entire small (˜4--10 m diameter) near-Earth asteroid (NEA) inside a large inflatable bag. However, NASA is also examining another option that entails retrieving a boulder (˜1--5 m) via robotic manipulators from the surface of a larger (˜100+ m) pre-characterized NEA. The Robotic Boulder Capture (RBC) option can leverage robotic mission data to help ensure success by targeting previously (or soon to be) well-characterized NEAs. For example, the data from the Japan Aerospace Exploration Agency's (JAXA) Hayabusa mission has been utilized to develop detailed mission designs that assess options and risks associated with proximity and surface operations. Hayabusa's target NEA, Itokawa, has been identified as a valid target and is known to possess hundreds of appropriately sized boulders on its surface. Further robotic characterization of additional NEAs (e.g., Bennu and 1999 JU_3) by NASA's OSIRIS REx and JAXA's Hayabusa 2 missions is planned to begin in 2018. This ARM option reduces mission risk and provides increased benefits for science, human exploration, resource utilization, and planetary defense.

  7. Origin of the Asteroid Belt and Mars' Small Mass

    Science.gov (United States)

    Walsh, Kevin J.; Morbidelli, A.; Raymond, S. N.; O'Brien, D. P.; Mandell, A.

    2010-10-01

    Reproducing the small mass of Mars is a major problem for modern simulations of terrestrial planet accretion (Raymond et al. 2009). Terrestrial planet formation simulations using a planetesimal disk with an outer edge at 1.0 AU have been found to form good Mars analogs (Hansen et al. 2009). However, these initial conditions appear inconsistent with solar system evolution and the asteroid belt. Hydrodynamical simulations show that the evolution of Jupiter and Saturn in a gas-disk generically leads to a two-stage, inward-then-outward migration (Masset & Snellgrove 2001, Morbidelli & Crida 2007, Pierens & Nelson 2008). We present simulations showing that if Jupiter's minimal orbital radius was 1.5 AU, this evolution both truncates the planetesimal disk at 1.0 AU and repopulates the asteroid belt from two distinct parent populations. Our model links the origin of the inner solar system - explaining both the mass of Mars and the properties of the asteroid belt - to a realistic evolution of the giant planets. This scenario represents a paradigm shift in our understanding of the early evolution of the inner solar system. Previously S- and C-type asteroids were thought to have both originated in the 2--3 AU region, with comets forming far away beyond the giant planets. This posed problems in explaining the vast physical differences between S- and C-type asteroids, and the physical similarities between comets and C-type asteroids as shown by Stardust and micrometeorite samples (Brownlee et al. 2006, Gounelle et al. 2008). Our presented scenario finds that S-types likely formed in the 1--3 AU region, with C-types and comets forming in the outer regions of the disk. This provides a much better qualitative explanation of the observed differences and similarities. This work is part of the Helmholtz Alliances "Planetary Evolution and Life", which KJW and AM thank for financial support.

  8. Asteroid retrieval missions enabled by invariant manifold dynamics

    Science.gov (United States)

    Sánchez, Joan Pau; García Yárnoz, Daniel

    2016-10-01

    Near Earth Asteroids are attractive targets for new space missions; firstly, because of their scientific importance, but also because of their impact threat and prospective resources. The asteroid retrieval mission concept has thus arisen as a synergistic approach to tackle these three facets of interest in one single mission. This paper reviews the methodology used by the authors (2013) in a previous search for objects that could be transported from accessible heliocentric orbits into the Earth's neighbourhood at affordable costs (or Easily Retrievable Objects, a.k.a. EROs). This methodology consisted of a heuristic pruning and an impulsive manoeuvre trajectory optimisation. Low thrust propulsion on the other hand clearly enables the transportation of much larger objects due to its higher specific impulse. Hence, in this paper, low thrust retrieval transfers are sought using impulsive trajectories as first guesses to solve the optimal control problem. GPOPS-II is used to transcribe the continuous-time optimal control problem to a nonlinear programming problem (NLP). The latter is solved by IPOPT, an open source software package for large-scale NLPs. Finally, a natural continuation procedure that increases the asteroid mass allows to find out the largest objects that could be retrieved from a given asteroid orbit. If this retrievable mass is larger than the actual mass of the asteroid, the asteroid retrieval mission for this particular object is said to be feasible. The paper concludes with an updated list of 17 EROs, as of April 2016, with their maximum retrievable masses by means of low thrust propulsion. This ranges from 2000 tons for the easiest object to be retrieved to 300 tons for the least accessible of them.

  9. Spatial Reasoning Training Through Light Curves Of Model Asteroids

    Science.gov (United States)

    Ziffer, Julie; Nakroshis, Paul A.; Rudnick, Benjamin T.; Brautigam, Maxwell J.; Nelson, Tyler W.

    2015-11-01

    Recent research has demonstrated that spatial reasoning skills, long known to be crucial to math and science success, are teachable. Even short stints of training can improve spatial reasoning skills among students who lack them (Sorby et al., 2006). Teaching spatial reasoning is particularly valuable to women and minorities who, through societal pressure, often doubt their spatial reasoning skill (Hill et al., 2010). We have designed a hands on asteroid rotation lab that provides practice in spatial reasoning tasks while building the student’s understanding of photometry. For our tool, we mount a model asteroid, with any shape of our choosing, on a slowly rotating motor shaft, whose speed is controlled by the experimenter. To mimic an asteroid light curve, we place the model asteroid in a dark box, shine a movable light source upon our asteroid, and record the light reflected onto a moveable camera. Students may then observe changes in the light curve that result from varying a) the speed of rotation, b) the model asteroid’s orientation with respect to the motor axis, c) the model asteroid’s shape or albedo, and d) the phase angle. After practicing with our tool, students are asked to pair new objects to their corresponding light curves. To correctly pair objects to their light curves, students must imagine how light scattering off of a three dimensional rotating object is imaged on a ccd sensor plane, and then reduced to a series of points on a light curve plot. Through the use of our model asteroid, the student develops confidence in spatial reasoning skills.

  10. Discovery of Spin-Rate-Dependent Asteroid Thermal Inertia

    Science.gov (United States)

    Harris, Alan; Drube, Line

    2016-10-01

    Knowledge of the surface thermal inertia of an asteroid can provide insight into surface structure: porous material has a lower thermal inertia than rock. Using WISE/NEOWISE data and our new asteroid thermal-inertia estimator we show that the thermal inertia of main-belt asteroids (MBAs) appears to increase with spin period. Similar behavior is found in the case of thermophysically-modeled thermal inertia values of near-Earth objects (NEOs). We interpret our results in terms of rapidly increasing material density and thermal conductivity with depth, and provide evidence that thermal inertia increases by factors of 10 (MBAs) to 20 (NEOs) within a depth of just 10 cm. On the basis of a picture of depth-dependent thermal inertia our results suggest that, in general, thermal inertia values representative of solid rock are reached some tens of centimeters to meters below the surface in the case of MBAs (the median diameter in our dataset = 24 km). In the case of the much smaller (km-sized) NEOs a thinner porous surface layer is indicated, with large pieces of solid rock possibly existing just a meter or less below the surface. These conclusions are consistent with our understanding from in-situ measurements of the surfaces of the Moon, and a few asteroids, and suggest a very general picture of rapidly changing material properties in the topmost regolith layers of asteroids. Our results have important implications for calculations of the Yarkovsky effect, including its perturbation of the orbits of potentially hazardous objects and those of asteroid family members after the break-up event. Evidence of a rapid increase of thermal inertia with depth is also an important result for studies of the ejecta-enhanced momentum transfer of impacting vehicles ("kinetic impactors") in planetary defense.

  11. 3-D Printed Asteroids for Outreach Astronomy Education

    Science.gov (United States)

    Russell, April

    2015-11-01

    3-D printed asteroids provide new opportunities for outreach astronomy education due to their low cost, interactive potential, and high interest value. Telescopes are expensive, bulky, fragile, and cannot be used effectively during the day. 3-D printing of asteroids combines exciting new technology with astronomy, appealing to a broader audience. The printed models are scientifically accurate, as their shapes have been modeled using light-curve inversion techniques using and occultation data to provide a jumping off point for discussions of these advanced and exciting topics.

  12. Comet or asteroid shower in the late Eocene?

    Science.gov (United States)

    Tagle, Roald; Claeys, Philippe

    2004-07-23

    The passage of a comet shower approximately 35 million years ago is generally advocated to explain the coincidence during Earth's late Eocene of an unusually high flux of interplanetary dust particles and the formation of the two largest craters in the Cenozoic, Popigai and the Chesapeake Bay. However, new platinum-group element analyses indicate that Popigai was formed by the impact of an L-chondrite meteorite. Such an asteroidal projectile is difficult to reconcile with a cometary origin. Perhaps instead the higher delivery rate of extraterrestrial matter, dust, and large objects was caused by a major collision in the asteroid belt.

  13. SOFIA + FORCAST Observations of 10 Aqueously Altered Asteroids

    Science.gov (United States)

    McAdam, Margaret; Sunshine, Jessica M.; Kelley, Michael S.; Bus, Schelte J.

    2016-10-01

    Aqueous alteration, or the reaction of water and minerals to produce hydrated minerals, has affected certain groups of carbonaceous meteorites (e.g., the CM and CI meteorites) and asteroids. In the visible/near-infrared (VNIR), CM/CI meteorites and some dark C-complex asteroids are known to have 0.7-µm absorptions that indicate the presence of hydrated minerals [1, 2, 3]. However, this feature does not provide any information about the amount of hydrated minerals in asteroids or meteorites [1]. In contrast, at mid-infrared (MIR) wavelengths, strong spectral features change continuously with amount of hydrated minerals in a suite of well-characterized CM/CI meteorites [1].Using these results, we analyze the spectra of 10 C-complex asteroids observed by SOFIA + FORCAST. These targets are large objects (>95 km diameter) situated in the mid to outer Main Asteroid Belt (2.4 – 3.4 AU). We present spectra of the following asteroids, spectral types in parentheses: 36 Atalante (C), 38 Leda (Cgh), 62 Erato (Ch), 121 Hermione (Ch), 165 Loreley (Cb), 194 Prokne (C), 203 Pompeja (C), 266 Aline (Ch), 52 Europa (Ch), and 19 Fortuna (Ch). Spectra were obtained in two wavelength regions: 8.5-13.6-μm and 17.6-27.7-μm. In these spectral regions, mineralogical features that are known to change continuously with amount of hydrated minerals appear. Most of these targets are known to have hydrated minerals on their surfaces by the presence of the 0.7-μm feature [e.g. 3, 4] or from observations in the 3-μm region [5]. We interpret the spectral features observed using SOFIA and estimate the abundances of hydrated minerals for each asteroid. Additionally, we compare these observations to Spitzer observations of similar objects. A subset of these asteroids have also been measured in VNIR, which allows us to directly compare the signatures of hydration in both the VNIR and the MIR.[1] McAdam et al., (2015), Icarus, 245, 320-332. [2] Cloutis, et al., (2011), Icarus, 216, 309-346. [3

  14. Photometry and Lightcurve Analysis of 7 Main-Belt Asteroids

    Science.gov (United States)

    Violante, Renata; Leake, M. A.

    2013-01-01

    We report the synodic periods and lightcurves for three main-belt asteroids and provide lightcurves for four other main-belt asteroids. 676 Melitta has a period of 8.35 ± 0.05 hours, with an amplitude of 0.056 ± 0.026 magnitude; 688 Melanie has a period of 16.10 ± 0.05 hours, and an amplitude of 0.091 ± 0.019 magnitude; 1677 Tycho Brahe has a period of 3.89 ± 0.06 hours, and an amplitude of 0.564 ± 0.011 magnitude.

  15. Note about the impact possibilities of asteroid (99942) Apophis

    OpenAIRE

    2010-01-01

    The Monte Carlo method of the nominal orbit clonning was applied to the case of 99942 Apophis, the asteroid from the Aten group. Calculations based on observations from the time interval of 2004 03 15 - 2008 01 09 have shown that the asteroid will pass near Earth in 2029 at the minimum distance of 5.921 \\pm 0.042 R_{Earth}, what implies that the likelihood that Apophis strikes the planet at 2036 April 13 increased to 4.5\\times 10^{-6} (from about 6\\times 10^{-7} previously announced by us in ...

  16. Guide to the universe asteroids, comets, and dwarf planets

    CERN Document Server

    Rivkin, Andrew

    2009-01-01

    This volume in the Greenwood Guides to the Universe series covers asteroids, comets, and dwarf planets-those small bodies that revolve the Sun-and provides readers with the most up-to-date understanding of the current state of scientific knowledge about them. Scientifically sound, but written with the student in mind, Asteroids, Comets, and Dwarf Planets is an excellent first step for researching the exciting scientific discoveries of the smallest celestial bodies in the solar system.||The book will introduce students to all of the areas of research surrounding the subject, answering many intr

  17. IMPROVED ALGORITHMS FOR RADAR-BASED RECONSTRUCTION OF ASTEROID SHAPES

    Energy Technology Data Exchange (ETDEWEB)

    Greenberg, Adam H.; Margot, Jean-Luc [University California, Los Angeles, CA (United States)

    2015-10-15

    We describe our implementation of a global-parameter optimizer and Square Root Information Filter into the asteroid-modeling software shape. We compare the performance of our new optimizer with that of the existing sequential optimizer when operating on various forms of simulated data and actual asteroid radar data. In all cases, the new implementation performs substantially better than its predecessor: it converges faster, produces shape models that are more accurate, and solves for spin axis orientations more reliably. We discuss potential future changes to improve shape's fitting speed and accuracy.

  18. EVIDENCE FOR GAS FROM A DISINTEGRATING EXTRASOLAR ASTEROID

    Energy Technology Data Exchange (ETDEWEB)

    Xu, S. [European Southern Observatory, Karl-Schwarzschild-Straße 2, D-85748 Garching (Germany); Jura, M.; Zuckerman, B. [Department of Physics and Astronomy, University of California, Los Angeles CA 90095-1562 (United States); Dufour, P., E-mail: sxu@eso.org, E-mail: jura@astro.ucla.edu, E-mail: ben@astro.ucla.edu, E-mail: dufourpa@astro.umontreal.ca [Institut de Recherche sur les Exoplanètes (iREx), Université de Montréal, Montréal, QC H3C 3J7 (Canada)

    2016-01-10

    We report high-resolution spectroscopic observations of WD 1145+017—a white dwarf that was recently found to be transitted by multiple asteroid-sized objects within its tidal radius. We discovered numerous circumstellar absorption lines with linewidths of ∼300 km s{sup −1} from Mg, Ca, Ti, Cr, Mn, Fe, and Ni, possibly from several gas streams produced by collisions among the actively disintegrating objects. The atmosphere of WD 1145+017 is polluted with 11 heavy elements, including O, Mg, Al, Si, Ca, Ti, V:, Cr, Mn, Fe, and Ni. Evidently, we are witnessing the active disintegration and subsequent accretion of an extrasolar asteroid.

  19. Size Sorting on the Rubble-Pile Asteroid Itokawa

    Science.gov (United States)

    Shinbrot, Troy; Sabuwala, Tapan; Siu, Theo; Vivar Lazo, Miguel; Chakraborty, Pinaki

    2017-03-01

    Photographs of the asteroid Itokawa reveal unexpectedly strong size segregation between lowlands populated almost entirely by small pebbles and highlands consisting of larger boulders. We propose that this segregation may be caused by a simple and unexplored effect: pebbles accreting onto the asteroid rebound from boulders, but sink into pebbly regions. By number, overwhelmingly more particles on Itokawa are pebbles, and collisions involving these pebbles must unavoidably cause pebbly regions to grow. We carry out experiments and simulations that demonstrate that this mechanism of size sorting based on simple counting of grains produces strong lateral segregation that reliably obeys an analytic formula.

  20. Nuclear cycler: An incremental approach to the deflection of asteroids

    Science.gov (United States)

    Vasile, Massimiliano; Thiry, Nicolas

    2016-04-01

    This paper introduces a novel deflection approach based on nuclear explosions: the nuclear cycler. The idea is to combine the effectiveness of nuclear explosions with the controllability and redundancy offered by slow push methods within an incremental deflection strategy. The paper will present an extended model for single nuclear stand-off explosions in the proximity of elongated ellipsoidal asteroids, and a family of natural formation orbits that allows the spacecraft to deploy multiple bombs while being shielded by the asteroid during the detonation.

  1. Power Supply for a Manned International Asteroid Mission

    Science.gov (United States)

    Weingartner, Stefan; Nahra, Henry K.; Kohout, Lisa L.; Larin, Max

    1991-01-01

    A feasibility study considering the exploitation of a near Earth asteroid was performed. The power requirements and proposed power systems for the crew vehicle, cargo vehicles, mining and processing equipment are described. A photovoltaic power system was selected to meet the 52.1 kWe and the 3.9 kWe power requirements of the crew and cargo vehicles, respectively. A nuclear power plant using a thermodynamic Rankine cycle with a total mass of 62.1 tons was chosen to provide the 7.225 MWe and the 5.5 MWth required for the mining and processing activities at the asteroid.

  2. Asteroid data mining and precoveries in the Gaia area

    OpenAIRE

    Thuillot, William; Bancelin, David; Desmars, Josselin; Hestroffer, Daniel

    2012-01-01

    Program available at: http://www.imcce.fr/hosted_sites/naroo/program.html; International audience; Asteroids are components of a very large family of the Solar System. We denote more than 590 000 such objects at the present date. As soon as there is a discovery of an asteroid, a preliminary orbit can be calculated and the improvement of this orbit can be performed thanks to new observations to be done starting from their discovery. But ancient observations can also be retrieved in the past. T...

  3. Constraining the wavelength dependence of polarization for various asteroid taxonomies

    Science.gov (United States)

    Maleszewski, Chester; Smith, Paul S.; McMillan, Robert S.

    2016-10-01

    The polarization of sunlight reflected from asteroids is known to be inversely proportional to geometric albedo (Umov 1905). However, that was mainly derived from observations in the V-filter. Preliminary observations of the wavelength dependence were conducted by Belskaya et al. (2009) in the major asteroid taxonomic classes. The limited UBVRI data revealed trends of spectral slope vs. phase angle. To study the wavelength dependence of asteroid polarization more robustly, we have used the SPOL spectropolarimeter at the 2.3-m Bok and 1.6-m Kuiper telescopes. The finer spectral resolution of spectropolarimetry is needed to confirm the linearity of the wavelength dependence of polarization.We present polarization spectra from four asteroid taxonomic groups: B-, C-, S-, and X-types. Across the observed wavelength range (0.45 to 0.7 microns), the linear trend described by Belskaya et al. is confirmed and we determined the best-fit linear slope of each spectrum. For the S-type asteroids, the slope of the polarization spectra becomes more negative as the phase angle increases. The rate at which the polarization slope changes increases at phase angles greater than the inversion angle. C-type asteroids behave differently from the S-types in two ways. First, the polarization spectra for the C-types are positively sloped as opposed to negative (also noted in Belskaya et al.). Also, as you observe the C-types closer to the inversion angle (~20 degrees phase angle), the polarization slopes tend to flatten as opposed to steepen. The polarization spectra of B-type asteroids are positively sloped, but the tendency to flatten near the inversion angle like the C-type spectra is not evident. Our observations of low albedo X-types exhibit positive polarization slopes, while the high albedo observations exhibit negative slopes. Differences in the wavelength dependencies of polarization between various asteroid types appear to be driven by differences in their geometric albedos. Better

  4. Temporary Capture of Asteroids by a Planet: Dependence of Prograde/Retrograde Capture on Asteroids' Semimajor Axes

    CERN Document Server

    Higuchi, Arika

    2015-01-01

    We have investigated the dependence of the prograde/retrograde temporary capture of asteroids by a planet on their original heliocentric semimajor axes through analytical arguments and numerical orbital integrations in order to discuss the origins of irregular satellites of giant planets. We found that capture is mostly retrograde for the asteroids near the planetary orbit and is prograde for those from further orbits. An analytical investigation reveals the intrinsic dynamics of these dependences and gives boundary semimajor axes for the change in prograde/retrograde capture. The numerical calculations support the idea of deriving the analytical formulae and confirm their dependence. Our numerical results show that the capture probability is much higher for bodies from the inner region than for outer ones. These results imply that retrograde irregular satellites of Jupiter are most likely to be captured bodies from the nearby orbits of Jupiter that may have the same origin as Trojan asteroids, while prograde...

  5. THE UV/BLUE EFFECTS OF SPACE WEATHERING MANIFESTED IN S-COMPLEX ASTEROIDS. I. QUANTIFYING CHANGE WITH ASTEROID AGE

    Energy Technology Data Exchange (ETDEWEB)

    Vilas, Faith [MMT Observatory, Tucson, AZ (United States); Hendrix, Amanda R., E-mail: fvilas@psi.edu [Planetary Science Institute, 1700 E. Fort Lowell Rd., Suite 106, Tucson, AZ 85719 (United States)

    2015-08-15

    Evidence for the manifestation of space weathering in S-complex asteroids as a bluing of the UV/blue reflectance spectrum is extended using high resolution CCD reflectance spectra of 21 main-belt, 1 Mars-crossing, and 3 near-Earth asteroids covering a wavelength range of 320–620 nm. Demonstration of the transition of iron-bearing materials from volume scattering to surface (Fresnel) scattering is apparent as an abrupt downturn at wavelengths just short of 400 nm in reflectance spectra of fresh asteroid surfaces. The weathering away of this downturn is demonstrated by its absence in reflectance spectra of mature S-complex asteroids, consistent with an increase in npFe{sup 0} on the material's surface. Modeling of the effects of the addition of small amounts of npFe{sup 0} to particles from both a hypothetical mineral and a terrestrial basalt shows that evidence of the addition of 0.0001% npFe{sup 0} affects the reflectance at UV/blue wavelengths, while the addition of 0.01% is required to see the visible/near-infrared reddening and diminution of absorption features. Thus, the UV/blue reflectance characteristics allow earlier detection of the onset of space weathering effects. Combining UV/blue spectral characteristics of asteroids and ordinary chondrite meteorites with estimated ages of the young Datura family, we establish a method of dating asteroid surface ages during the early stages of space weathering. We demonstrate by dating the surface of NEA 163249 2002 GT to be 109 (±18) to 128 (±10) Kyr.

  6. NASA's Human Mission to a Near-Earth Asteroid: Landing on a Moving Target

    Science.gov (United States)

    Smith, Jeffrey H.; Lincoln, William P.; Weisbin, Charles R.

    2011-01-01

    This paper describes a Bayesian approach for comparing the productivity and cost-risk tradeoffs of sending versus not sending one or more robotic surveyor missions prior to a human mission to land on an asteroid. The expected value of sample information based on productivity combined with parametric variations in the prior probability an asteroid might be found suitable for landing were used to assess the optimal number of spacecraft and asteroids to survey. The analysis supports the value of surveyor missions to asteroids and indicates one launch with two spacecraft going simultaneously to two independent asteroids appears optimal.

  7. AcuA: the AKARI/IRC Mid-infrared Asteroid Survey

    CERN Document Server

    Usui, Fumihiko; Mueller, Thomas G; Hasegawa, Sunao; Ishiguro, Masateru; Ootsubo, Takafumi; Ishihara, Daisuke; Kataza, Hirokazu; Takita, Satoshi; Oyabu, Shinki; Ueno, Munetaka; Matsuhara, Hideo; Onaka, Takashi

    2011-01-01

    We present the results of an unbiased asteroid survey in the mid-infrared wavelength with the Infrared Camera (IRC) onboard the Japanese infrared satellite AKARI. About 20% of the point source events recorded in the AKARI All-Sky Survey observations are not used for the IRC Point Source Catalog (IRC-PSC) in its production process because of the lack of multiple detection by position. Asteroids, which are moving objects on the celestial sphere, remain in these "residual events". We identify asteroids out of the residual events by matching them with the positions of known asteroids. For the identified asteroids, we calculate the size and albedo based on the Standard Thermal Model. Finally we have a brand-new catalog of asteroids, named the Asteroid Catalog Using Akari (AcuA), which contains 5,120 objects, about twice as many as the IRAS asteroid catalog. The catalog objects comprise 4,953 main belt asteroids, 58 near Earth asteroids, and 109 Jovian Trojan asteroids. The catalog will be publicly available via th...

  8. Digital Tracking Observations Can Discover Asteroids Ten Times Fainter than Conventional Searches

    CERN Document Server

    Heinze, Aren; Trollo, Joseph

    2015-01-01

    We describe digital tracking, a method for asteroid searches that greatly increases the sensitivity of a telescope to faint unknown asteroids. It has been previously used to detect faint Kuiper Belt objects using the Hubble Space Telescope and large ground-based instruments, and to find a small, fast-moving asteroid during a close approach to Earth. We complement this earlier work by developing digital tracking methodology for detecting asteroids using large-format CCD imagers. We demonstrate that the technique enables the ground-based detection of large numbers of new faint asteroids. Our methodology resolves or circumvents all major obstacles to the large-scale application of digital tracking for finding main belt and near-Earth asteroids. We find that for both asteroid populations, digital tracking can deliver a factor of ten improvement over conventional searches. Digital tracking has long been standard practice for deep Kuiper Belt surveys, but even there our methodology enables deeper integrations than ...

  9. Earth-crossing asteroids - Orbital classes, collision rates with earth, and origin

    Science.gov (United States)

    Shoemaker, E. M.; Williams, J. G.; Helin, E. F.; Wolfe, R. F.

    1979-01-01

    Asteroids that can intersect the orbit of the earth are discussed, which include Aten asteroids (semimajor axis (a) less than 1 AU, aphelion greater than 0.983 AU), Apollo asteroids (a greater than 1 AU, perihelion less than 1.017 AU), and Amor asteroids (perihelion distance between 1.017 and 1.3 AU). The principal sources of earth-crossing asteroids appear to be extinct comet nuclei and collision fragments from regions in the main asteroid belt. The total population of earth-crossers is estimated at 13,000, of which approximately 8% are Atens, 50% are Apollos, and 40% are Amors,and the present collision rate of such asteroids with the earth is estimated at about 3.5 objects, to absolute magnitude 18, per million years.

  10. Orbital stability zones about asteroids. II - The destabilizing effects of eccentric orbits and of solar radiation

    Science.gov (United States)

    Hamilton, Douglas P.; Burns, Joseph A.

    1992-03-01

    Recently, Hamilton and Burns (1991) characterized the size and shape of a stability zone around an asteroid on a circular heliocentric orbit within which asteroid material could remain bound for an extended period of time. The present paper considers two additional effects: the asteroid's nonzero heliocentric eccentricity and solar radiation pressure. Results of numerical analyses show that, for an asteroid on an eccentric orbit, the stability zone scales roughly as the size of the Hill sphere calculated at the asteroid's pericenter. It was also found that solar radiation pressure is a very efficient mechanism for removing small (on the order of 0.1 mm) particles from circular asteroidal zone. Particles larger than a few centimeters are only slightly affected by radiation pressure. The results are applied to the Gaspra 951 asteroid.

  11. Footprints of a possible Ceres asteroid paleo-family

    CERN Document Server

    Carruba, V; Marchi, S; Aljbaae, S

    2016-01-01

    Ceres is the largest and most massive body in the asteroid main belt. Observational data from the Dawn spacecraft reveal the presence of at least two impact craters about 280~km in diameter on the Ceres surface, that could have expelled a significant number of fragments. Yet, standard techniques for identifying dynamical asteroid families have not detected any Ceres family. In this work, we argue that linear secular resonances with Ceres deplete the population of objects near Ceres. Also, because of the high escape velocity from Ceres, family members are expected to be very dispersed, with a considerable fraction of km-sized fragments that should be able to reach the pristine region of the main belt, the area between the 5J:-2A and 7J:-3A mean-motion resonances, where the observed number of asteroids is low. Rather than looking for possible Ceres family members near Ceres, here we propose to search in the pristine region. We identified 156 asteroids whose taxonomy, colors, albedo could be compatible with bein...

  12. Extrasolar asteroid mining as forensic evidence for extraterrestrial intelligence

    Science.gov (United States)

    Forgan, Duncan H.; Elvis, Martin

    2011-10-01

    The development of civilisations like ours into spacefaring, multi-planet entities requires significant raw materials to construct vehicles and habitats. Interplanetary debris, including asteroids and comets, may provide such a source of raw materials. In this article we present the hypothesis that extraterrestrial intelligences (ETIs) engaged in asteroid mining may be detectable from Earth. Considering the detected disc of debris around Vega as a template, we explore the observational signatures of targeted asteroid mining (TAM), such as unexplained deficits in chemical species, changes in the size distribution of debris and other thermal signatures which may be detectable in the spectral energy distribution (SED) of a debris disc. We find that individual observational signatures of asteroid mining can be explained by natural phenomena, and as such they cannot provide conclusive detections of ETIs. But, it may be the case that several signatures appearing in the same system will prove harder to model without extraterrestrial involvement. Therefore signatures of TAM are not detections of ETI in their own right, but as part of "piggy-back" studies carried out in tandem with conventional debris disc research, they could provide a means of identifying unusual candidate systems for further study using other SETI techniques.

  13. Fourth-order gravity gradient torque of spacecraft orbiting asteroids

    CERN Document Server

    Wang, Yue; Xu, Shijie

    2014-01-01

    The dynamical behavior of spacecraft around asteroids is a key element in design of such missions. An asteroid's irregular shape, non-spherical mass distribution and its rotational sate make the dynamics of spacecraft quite complex. This paper focuses on the gravity gradient torque of spacecraft around non-spherical asteroids. The gravity field of the asteroid is approximated as a 2nd degree and order-gravity field with harmonic coefficients C20 and C22. By introducing the spacecraft's higher-order inertia integrals, a full fourth-order gravity gradient torque model of the spacecraft is established through the gravitational potential derivatives. Our full fourth-order model is more precise than previous fourth-order model due to the consideration of higher-order inertia integrals of the spacecraft. Some interesting conclusions about the gravity gradient torque model are reached. Then a numerical simulation is carried out to verify our model. In the numerical simulation, a special spacecraft consisted of 36 po...

  14. Itokawa is not Brazil: granular segregation on asteroids

    Science.gov (United States)

    Shinbrot, Troy; Chakraborty, Pinaki; Sabuwala, Tapan

    2015-11-01

    Recent photographs of the asteroid Itokawa have revealed strong separation between regions populated almost entirely by sand and other regions consisting only of larger boulders. This size separation has been attributed to the Brazil Nut Effect (BNE), however we point out here that the BNE depends on conditions such as isotropic gravity, parallel sidewalls and periodic vertical shaking that are wholly absent on asteroids. On the other hand, surface areas of boulders and sand appear to be comparable on Itokawa, and in this situation it follows that the asteroid must have suffered many orders of magnitude more collisions with sand particles than with boulders. We observe that a sand particle will tend to bounce off of a boulder but will sink into a sea of similar sand particles, and so we predict that sand seas must grow on such asteroids. We carry out experiments and simulations to evaluate this and related predictions, and we demonstrate that this new mechanism of segregation based on simple counting of grains can produce the strong separation of sizes reported.

  15. On the Title of Moriarty's 'Dynamics of an Asteroid'

    CERN Document Server

    Jenkins, Alejandro

    2013-01-01

    We propose an explanation of the title of Prof. James Moriarty's treatise_Dynamics of an Asteroid_, a scientific work mentioned by Sherlock Holmes in_The Valley of Fear_ and prominently featured in Guy Ritchie's 2011 film_Sherlock Holmes: A Game of Shadows_. Our views on the subject differ from those expressed in Isaac Asimov's "The Ultimate Crime".

  16. Modeling Orbital Gamma-Ray Spectroscopy Experiments at Carbonaceous Asteroids

    CERN Document Server

    Lim, Lucy F; Evans, Larry G; Parsons, Ann M; Zolensky, Michael E; Boynton, William V

    2016-01-01

    To evaluate the feasibility of measuring differences in bulk composition among carbonaceous meteorite parent bodies from an asteroid or comet orbiter, we present the results of a performance simulation of an orbital gamma-ray spectroscopy ("GRS") experiment in a Dawn-like orbit around spherical model asteroids with a range of carbonaceous compositions. The orbital altitude was held equal to the asteroid radius for 4.5 months. Both the asteroid gamma-ray spectrum and the spacecraft background flux were calculated using the MCNPX Monte-Carlo code. GRS is sensitive to depths below the optical surface (to ~20--50 cm depth depending on material density). This technique can therefore measure underlying compositions beneath a sulfur-depleted (e.g., Nittler et al. 2001) or desiccated surface layer. We find that 3\\sigma\\ uncertainties of under 1 wt% are achievable for H, C, O, Si, S, Fe, and Cl for five carbonaceous meteorite compositions using the heritage Mars Odyssey GRS design in a spacecraft- deck-mounted configu...

  17. Modeling orbital gamma-ray spectroscopy experiments at carbonaceous asteroids

    Science.gov (United States)

    Lim, Lucy F.; Starr, Richard D.; Evans, Larry G.; Parsons, Ann M.; Zolensky, Michael E.; Boynton, William V.

    2017-01-01

    To evaluate the feasibility of measuring differences in bulk composition among carbonaceous meteorite parent bodies from an asteroid or comet orbiter, we present the results of a performance simulation of an orbital gamma-ray spectroscopy (GRS) experiment in a Dawn-like orbit around spherical model asteroids with a range of carbonaceous compositions. The orbital altitude was held equal to the asteroid radius for 4.5 months. Both the asteroid gamma-ray spectrum and the spacecraft background flux were calculated using the MCNPX Monte-Carlo code. GRS is sensitive to depths below the optical surface (to ≈20-50 cm depth depending on material density). This technique can therefore measure underlying compositions beneath a sulfur-depleted (e.g., Nittler et al.) or desiccated surface layer. We find that 3σ uncertainties of under 1 wt% are achievable for H, C, O, Si, S, Fe, and Cl for five carbonaceous meteorite compositions using the heritage Mars Odyssey GRS design in a spacecraft-deck-mounted configuration at the Odyssey end-of-mission energy resolution, FWHM = 5.7 keV at 1332 keV. The calculated compositional uncertainties are smaller than the compositional differences between carbonaceous chondrite subclasses.

  18. Dynamical evolution and chronology of the Hygiea asteroid family

    CERN Document Server

    Carruba, V; Huaman, M E; Santos, C R dos; Souami, D

    2013-01-01

    The asteroid (10) Hygiea is the fourth largest asteroid of the Main Belt, by volume and mass, and it is the largest member of its own family. Previous works investigated the long-term effects of close encounters with (10) Hygiea of asteroids in the orbital region of the family, and analyzed the taxonomical and dynamical properties of members of this family. In this paper we apply the high-quality SDSS-MOC4 taxonomic scheme of DeMeo and Carry (2013) to members of the Hygiea family core and halo, we obtain an estimate of the minimum time and number of encounter necessary to obtain a $3\\sigma$ (or 99.7%) compatible frequency distribution function of changes in proper $a$ caused by close encounters with (10) Hygiea, we study the behavior of asteroids near secular resonance configurations, in the presence and absence of the Yarkovsky force, and obtain a first estimate of the age of the family based on orbital diffusion by the Yarkovsky and YORP effects with two methods. The Hygiea family is at least 2 Byr old, wit...

  19. A multi-domain approach to asteroid families identification

    CERN Document Server

    Carruba, V; Nesvorný, D; Roig, F; Huaman, M E; Souami, D

    2013-01-01

    Previous works have identified families halos by an analysis in proper elements domains, or by using Sloan Digital Sky Survey-Moving Object Catalog data, fourth release (SDSS-MOC4) multi-band photometry to infer the asteroid taxonomy, or by a combination of the two methods. The limited number of asteroids for which geometric albedo was known until recently discouraged in the past the extensive use of this additional parameter, which is however of great importance in identifying an asteroid taxonomy. The new availability of geometric albedo data from the Wide-field Infrared Survey Explorer (WISE) mission for about 100,000 asteroids significantly increased the sample of objects for which such information, with some errors, is now known. In this work we proposed a new method to identify families halos in a multi-domain space composed by proper elements, SDSS-MOC4 (a*,i-z) colors, and WISE geometric albedo for the whole main belt (and the Hungaria and Cybele orbital regions). Assuming that most families were crea...

  20. Asteroids, comets, meteors, and their interrelations. Part II: Editorial review

    Science.gov (United States)

    Muinonen, Karri; Granvik, Mikael; Penttilä, Antti; Gritsevich, Maria

    2016-04-01

    The Asteroids, Comets, Meteors 2014 (ACM 2014) conference was organized in Helsinki in June 30-July 4, 2014, with the first collection of the peer-reviewed papers published in December 2015 in the Special Issue of Planetary and Space Science (Muinonen et al., 2015). The present issue contains the second collection of papers from ACM 2014.

  1. Albedo polarimétrico de asteroides del grupo Hungaria

    Science.gov (United States)

    Gil-Hutton, R.; Benavidez, P.

    La región del cinturón de asteroides en donde se encuentra el grupo de los Hungarias (a= 1.79 a 1.98 UA, i=15 a 40 grados) es la única zona donde es común encontrar objetos de tipo taxonómico E, caracterizados por altos albedos, colores relativamente neutros y espectros sin detalles. Este tipo de asteroides está relacionado espectralmente con ciertos meteoritos (aubritas) que indican la existencia de episodios de gran calentamiento que ocurrieron durante la formación del Sistema Solar. Como el espectro de los asteroides de tipo E es idéntico a los de tipo M y P, la única forma de clasificar un asteroide en alguno de estos tres tipos taxonómicos es mediante el albedo. En este trabajo se presentan resultados preliminares sobre la determinación polarimétrica de albedos para objetos de este grupo utilizando el polarímetro CASPROF de CASLEO.

  2. Sparse source configurations in radio tomography of asteroids

    Science.gov (United States)

    Pursiainen, S.; Kaasalainen, M.

    2014-07-01

    Our research targets at progress in non-invasive imaging of asteroids to support future planetary research and extra-terrestrial mining activities. This presentation concerns principally radio tomography in which the permittivity distribution inside an asteroid is to be recovered based on the radio frequency signal transmitted from the asteroid's surface and gathered by an orbiter. The focus will be on a sparse distribution (Pursiainen and Kaasalainen, 2013) of signal sources that can be necessary in the challenging in situ environment and within tight payload limits. The general goal in our recent research has been to approximate the minimal number of source positions needed for robust localization of anomalies caused, for example, by an internal void. Characteristic to the localization problem are the large relative changes in signal speed caused by the high permittivity of typical asteroid minerals (e.g. basalt), meaning that a signal path can include strong refractions and reflections. This presentation introduces results of a laboratory experiment in which real travel time data was inverted using a hierarchical Bayesian approach combined with the iterative alternating sequential (IAS) posterior exploration algorithm. Special interest was paid to robustness of the inverse results regarding changes of the prior model and source positioning. According to our results, strongly refractive anomalies can be detected with three or four sources independently of their positioning.

  3. Spectral properties of the largest asteroids associated with Taurid Complex

    CERN Document Server

    Popescu, M; Nedelcu, D A; Vaubaillon, J; Cristescu, C P

    2014-01-01

    We obtained spectra of six of the largest asteroids (2201, 4183, 4486, 5143, 6063, and 269690) associated with Taurid complex. The observations were made with the IRTF telescope equipped with the spectro-imager SpeX. Their taxonomic classification is made using Bus-DeMeo taxonomy. The asteroid spectra are compared with the meteorite spectra from the Relab database. Mineralogical models were applied to determine their surface composition. All the spectral analysis is made in the context of the already published physical data. Five of the objects studied in this paper present spectral characteristics similar to the S taxonomic complex. The spectra of ordinary chondrites (spanning H, L, and LL subtypes) are the best matches for these asteroid spectra. {\\bf The asteroid} (269690) 1996 RG3 presents a flat featureless spectrum which could be associated to a primitive C-type object. The increased reflectance above 2.1 microns constrains its geometrical albedo to a value around 0.03. While there is an important dynam...

  4. Variability of Thermal Infrared Emission from Near-Earth Asteroids

    NARCIS (Netherlands)

    Taylor, Patrick A.; Howell, E. S.; Magri, C.; Vervack, R. J.; Nolan, M. C.; Fernandez, Y. R.; Rivkin, A. S.; Mueller, M.

    2009-01-01

    We have measured thermal emission between 2 and 4 microns for several near-Earth asteroids (NEAs) of different taxonomic types with SpeX on the NASA IRTF. Initial results for individual P-, V-, and E-type NEAs were presented at last year's meeting (Howell et al., 2008). Here we present results for t

  5. The H and G magnitude system for asteroids

    Science.gov (United States)

    Dymock, R.

    2007-12-01

    This article is based on a presentation given at the Observers' Workshop held at the Open University in Milton Keynes on 2007 February 24. It can be viewed on the Asteroids and Remote Planets Section website at http://homepage.ntlworld.com/roger.dymock/index.htm

  6. On the possible origin of the asteroid (1) Ceres

    CERN Document Server

    Rogozin, Yury I

    2014-01-01

    The last three decades the asteroid (1) Ceres is an object of the intensive ground-and space-based observations. A new unusual contributing to these studies represents the recent detection of localized sources of water vapour releasing from its surface at a rate about 6 kg s-1 (K\\"uppers et al 2014). A drastic distinction between asteroid (1) Ceres and nearest the large asteroid (4) Vesta in terms of their composition and appearance emphasizes an urgent state of a problem of the possible origin of Ceres in the main asteroid belt. By analogy with the early assumptions of some well-known astronomers of Mercury and Mars as the escaped satellites of their host planets we have put forward and semi-empirically have justified a hypothesis for the plausible origin of Ceres as the satellite of a disrupted planet in the past orbited the Sun of ~ 5 AU. The orbital location of this host of Ceres beyond the snow line of the Solar System explains a formation the icy mantle of Ceres, which appears may be a water vapour sour...

  7. Scaling of granular convective velocity and timescale of asteroidal resurfacing

    Science.gov (United States)

    Yamada, Tomoya; Ando, Kousuke; Morota, Tomokatsu; Katsuragi, Hiroaki

    Granular convection is one of the well-known phenomena observed in a vertically vibrated granular bed. Recently, the possbile relation between granular convection and asteroidal surface processes has been discussed. The granular convection on the surface of small asteroids might be induced by seismic vibration resulting from meteorite impacts. To quantitatively evaluate the timescale of asteroidal resurfacing by granular convection, the granular convective velocity under various conditions must be revealed. As a first step to approach this problem, we experimentally study the velocity scaling of granular convection using a vertically vibrated glass-beads layer. By systematic experiments, a scaling form of granular convective velocity has been obtained. The obtained scaling form implies that the granular convective velocity can be written by a power-law product of two characteristic velocity components: vibrational and gravitational velocities. In addition, the system size dependence is also scaled. According to the scaling form, the granular convective velocity is almost proportional to gravitatinal acceleration. Using this scaling form, we have estimated the resurfacing timescale on small asteroid surface.

  8. Phase space transport in a map of asteroid motion

    Institute of Scientific and Technical Information of China (English)

    LiyongZHOU; YisuiSUN; JilinZHOU

    2000-01-01

    We have studied the chaotic transport in a nonlinear model directly applicable to asteroid motion. An exponential and an algebraic diffusion law are observed in different regions of the phase space. We have also investigated the effects of small perturbations and found they can not only accelerate but also decelerate the transport.

  9. SIMULTANEOUS LINEAR AND CIRCULAR OPTICAL POLARIMETRY OF ASTEROID (4) VESTA

    Energy Technology Data Exchange (ETDEWEB)

    Wiktorowicz, Sloane J.; Nofi, Larissa A., E-mail: sloanew@ucolick.org [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States)

    2015-02-10

    From a single 3.8 hr observation of the asteroid (4) Vesta at 13.°7 phase angle with the POlarimeter at Lick for Inclination Studies of Hot jupiters 2 (POLISH2) at the Lick Observatory Shane 3 m telescope, we confirm rotational modulation of linear polarization in the B and V bands. We measure the peak-to-peak modulation in the degree of linear polarization to be ΔP = (294 ± 35) × 10{sup −6} (ppm) and time-averaged ΔP/P = 0.0575 ± 0.0069. After rotating the plane of linear polarization to the scattering plane, asteroidal rotational modulation is detected with 12σ confidence and observed solely in Stokes Q/I. POLISH2 simultaneously measures Stokes I, Q, U (linear polarization), and V (circular polarization), but we detect no significant circular polarization with a 1σ upper limit of 78 ppm in the B band. Circular polarization is expected to arise from multiple scattering of sunlight by rough surfaces, and it has previously been detected in nearly all other classes of solar system bodies except for asteroids. Subsequent observations may be compared with surface albedo maps from the Dawn Mission, which may allow the identification of compositional variation across the asteroidal surface. These results demonstrate the high accuracy achieved by POLISH2 at the Lick 3 m telescope, which is designed to directly detect scattered light from spatially unresolvable exoplanets.

  10. Delivery of Organic Material and Water through Asteroid Impacts

    NARCIS (Netherlands)

    Mueller, Michael; Frantseva, Kateryna; van der Tak, Floris; Helmich, Frank P.

    2014-01-01

    Meteorites, specifically carbonaceous chondrites, are frequently invoked as the primary source of Earth's water and organic materials, crucial ingredients for the formation of life. We have started developing a dynamical model of the delivery of their parent bodies, primitive low-albedo asteroids, f

  11. Radar observations and physical model of asteroid 6489 Golevka

    Science.gov (United States)

    Hudson, R.; Ostro, S.; Jurgens, R.; Rosema, K.; Giorgini, J.; Winkler, R.; Rose, R.; Choate, D.; Cormier, R.; Franck, C.; Frye, R.; Howard, D.; Kelley, D.; Littlefair, R.; Slade, M.; Benner, L.; Thomas, M.; Mitchell, D.; Chodas, P.; Yeomans, D.; Scheeres, D.; Palmer, P.; Zaitsev, A.; Koyama, Y.; Nakamura, A.

    2000-01-01

    We report 8510-MHz (3,5-cm) radar observations of the Earth crossing asteroid (ECA) 6489 Golevka (1991 JX) obtained between June 3 and June 15, 1995, at Goldstone, the Very Large Array and the Evpatoria (Ukraine) and Kashima (Japan) radio antennas.

  12. The Distribution of Basaltic Asteroids in the Main Belt

    CERN Document Server

    Moskovitz, Nicholas A; Gaidos, Eric; Willman, Mark; Nesvorny, David; Fevig, Ronald; Ivezic, Zeljko

    2008-01-01

    We present the observational results of a survey designed to target and detect asteroids whose colors are similar to those of Vesta family members and thus may be considered as candidates for having a basaltic composition. Fifty basaltic candidates were selected with orbital elements that lie outside of the Vesta dynamical family. Optical and near-infrared spectra were used to assign a taxonomic type to 11 of the 50 candidates. Ten of these were spectroscopically confirmed as V-type asteroids, suggesting that most of the candidates are basaltic and can be used to constrain the distribution of basaltic material in the Main Belt. Using our catalog of V-type candidates and the success rate of the survey, we calculate unbiased size-frequency and semi-major axis distributions of V-type asteroids. These distributions, in addition to an estimate for the total mass of basaltic material, suggest that Vesta was the predominant contributor to the basaltic asteroid inventory of the Main Belt, however scattered planetesim...

  13. Treatment of Star Catalog Biases in Asteroid Astrometric Observations

    Science.gov (United States)

    2010-01-01

    orbit determinations are subject to catalog bias. Aside from events associated with 1 Ceres or 4 Vesta , most asteroid mass determination events thus far...Ceres or 4 Vesta ) with encounters after 1997, and with a significance (de- fined as the ratio of mass to mass uncertainty) greater than 2.5. The ‘‘best

  14. Asteroid families classification: exploiting very large data sets

    CERN Document Server

    Milani, Andrea; Knezevic, Zoran; Novakovic, Bojan; Spoto, Federica; Paolicchi, Paolo

    2013-01-01

    The number of asteroids with accurately determined orbits increases fast. The catalogs of asteroid physical observations have also increased, although the number of objects is still smaller than in the orbital catalogs. We developed a new approach to the asteroid family classification by combining the Hierarchical Clustering Method (HCM) with a method to add new members to existing families. This procedure makes use of the much larger amount of information contained in the proper elements catalogs, with respect to classifications using also physical observations for a smaller number of asteroids. Our work is based on the large catalog of the high accuracy synthetic proper elements (available from AstDyS). We first identify a number of core families; to these we attribute the next layer of smaller objects. Then, we remove all the family members from the catalog, and reapply the HCM to the rest. This gives both halo families which extend the core families and new independent families, consisting mainly of small...

  15. A new method for astrometric observations of asteroids

    Science.gov (United States)

    Pauwels, Thierry

    1992-01-01

    In this paper we propose a new method for photographic astrometric observations of asteroids. We discuss its advantages and disadvantages and compare them to the advantages and disadvantages of the classical photographic methods. The new method is best suited for observations on a spot where no CCD cameras, blink or stereo comparators are available and when a fast detection of unknown objects is required.

  16. Radar Observations of Main-Belt M-class Asteroids

    NARCIS (Netherlands)

    Shepard, Michael K.; Clark, B. E.; Ockert-Bell, M.; Nolan, M. C.; Howell, E. S.; Magri, C.; Giorgini, J. D.; Benner, L. A. M.; Ostro, S. J.; Harris, A. W.; Warner, B. D.; Stephens, R. D.; Mueller, M.

    2009-01-01

    Using the S-band radar at Arecibo Observatory, we have observed 19 Tholen M-class asteroids. The mean radar albedo for all our targets is 0.28 ± 0.13, considerably higher than the mean radar albedo of every other class (Magri et al. 2007, Icarus 186, 126-151). We find approximately one-third (six) o

  17. Meteorites in meteorites - Evidence for mixing among the asteroids

    Science.gov (United States)

    Wilkening, L. L.

    1977-01-01

    Inclusions of one type of meteorite enclosed in another have been found in several gas-rich meteorites, unequilibrated chondrites and mesosiderites. The inclusions in all but one case are chondritic; a majority are mineralogically and isotopically similar to carbonaceous chondrites. These meteorite mixtures most probably resulted from collisions among asteroids.

  18. Yarkovsky V-shape identification of asteroid families

    Science.gov (United States)

    Bolin, Bryce T.; Delbo, Marco; Morbidelli, Alessandro; Walsh, Kevin J.

    2016-10-01

    There are only a few known main belt (MB) asteroid families with ages greater than 2 Gyrs. Estimates based on the family producing collision rate suggest that the lack of >2 Gyr-old families may be due to a selection bias in current techniques used to identify families. Family fragments disperse in their orbital elements, semi-major axis, a, eccentricity, e and inclination, i due to secular resonances, close encounters with massive asteroids and the non-gravitational Yarkovsky force. This causes the family fragments to be indistinguishable from the background of the main belt making them more difficult to identify with the hierarchical clustering method (HCM) with increasing family age. The discovery of the Eulalia and Polana families in the inner belt relied on new techniques because they were overlapping families, also, or primarily, because Yarkovsky spreading over their 2 Gyr-old lifetime made them too disperse to be identified using the classical HCM. The techniques used to discover the Polana and Eulalia are modified here to identify asteroid families by searching for correlations between a and absolute magnitude, H, the family's characteristic V-shape. In addition to demonstrating the V-shape technique on known families such as Erigone, Vesta, Flora and Polana, we will present a new investigation of the asteroid belt with this new tool looking for old, previously unidentified families.

  19. Do Planetary Encounters Reset Surfaces of Near Earth Asteroids?

    CERN Document Server

    Nesvorny, David; Vokrouhlicky, David; Chapman, Clark R; Rafkin, Scot

    2010-01-01

    Processes such as the solar wind sputtering and micrometeorite impacts can modify optical properties of surfaces of airless bodies. This explains why spectra of the main belt asteroids, exposed to these `space weathering' processes over eons, do not match the laboratory spectra of ordinary chondrite (OC) meteorites. In contrast, an important fraction of Near Earth Asteroids (NEAs), defined as Q-types in the asteroid taxonomy, display spectral attributes that are a good match to OCs. Here we study the possibility that the Q-type NEAs underwent recent encounters with the terrestrial planets and that the tidal gravity (or other effects) during these encounters exposed fresh OC material on the surface (thus giving it the Q-type spectral properties). We used numerical integrations to determine the statistics of encounters of NEAs to planets. The results were used to calculate the fraction and orbital distribution of Q-type asteroids expected in the model as a function of the space weathering timescale, t_sw (see m...

  20. Sensitivity of Airburst Damage Prediction to Asteroid Characterization Uncertainty

    Science.gov (United States)

    Mathias, Donovan; Wheeler, Lorien; Dotson, Jessie L.

    2016-10-01

    Characterizing the level of risk posed by asteroid impacts is quintessential to developing informed mitigation criteria, response plans, and long-term survey and characterization strategies for potentially hazardous asteroids. A physics-based impact risk (PBIR) model has been created to assess the consequences of potential asteroid strikes by combining probabilistic sampling of uncertain impact parameters with numerical simulation of the atmospheric flight, breakup, and resulting ground damage for each sampled impact case. The model incudes a Monte Carlo framework that allows the uncertainties in the potential impact parameters to be described in terms of probability distributions, and produces statistical results that support inference regarding the threat level across those ranges. This work considers the PBIR model outputs in terms of potential threat characterization metrics for decision support. Several metrics are assessed, from the single estimated casualty (Ec) parameter to more descriptive distribution functions. Distributions are shown for aggregate risk, risk versus asteroid size, and risk to specific geographic regions. In addition, these results show how the uncertain properties of potential impactors can lead to different conclusions about optimal survey and characterization strategies.

  1. Evidence for the Nature of Space Weathering Spectral Signatures on Low Albedo Asteroids

    Science.gov (United States)

    Lantz, Cateline; Clark, B. E.; Barucci, M. A.

    2012-10-01

    We address an existing problem in understanding the reflected light spectral signatures of carbonaceous (low-albedo) asteroids. We know from observations of the moon and high-albedo asteroids that interplanetary surface processes (solar wind and micrometeorite bombardment) can alter the spectral properties of silicates. The problem is that we don’t understand how carbonaceous surfaces respond to surface processes. The question is, what are the spectral signatures of surface processes on low albedo asteroids? To answer this question, we need to study reflected light spectra of asteroid subsurface materials, and compare them with asteroid surface materials. In this work, we assume that primitive asteroids are the parent bodies of carbonaceous chondrites. We begin with a fairly well-established meteorite-asteroid link: several studies have found evidence that links the CM meteorites with the Ch/Cgh asteroids [Hiroi et ao. 1996; Fornasier et al. 1999]. Assuming this link, we reason that differences between spectra of particulate samples of the CM meteorites and spectra of the regolith of the asteroids can be due to either differences in textural properties, or differences caused by surface processes on the asteroid. Previous work has resulted in contradictory predictions. Asteroid color survey data analyzed by Lazzarin et al. (2006) predicted spectral reddening for low albedo asteroids. Laser irradiation experiments by Moroz et al. (1996; 2004; 2004b) indicated both reddening and blueing of various degrees. Our initial results indicate spectral blueing of up to 50%, with little to no concurrent albedo change. We used telescopic observations of 43 Ch and Cgh-type asteroids (0.4 to 2.5 microns) from Binzel, DeMeo, et al. (MIT) and Fornasier et al. (Obs. Paris). We compare them statistically with 106 CM meteorite spectra from RELAB. The goal of this work is to predict what the OSIRIS-REx mission will see at B-type asteroid (101955) 1999RQ36.

  2. NASA’s Asteroid Redirect Mission: The Boulder Capture Option

    Science.gov (United States)

    Abell, Paul; Nuth, Joseph A.; Mazanek, Dan D.; Merrill, Raymond G.; Reeves, David M.; Naasz, Bo J.

    2014-11-01

    NASA is examining two options for the Asteroid Redirect Mission (ARM), which will return asteroid material to a Lunar Distant Retrograde Orbit (LDRO) using a robotic solar-electric-propulsion spacecraft, called the Asteroid Redirect Vehicle (ARV). Once the ARV places the asteroid material into the LDRO, a piloted mission will rendezvous and dock with the ARV. After docking, astronauts will conduct two extravehicular activities (EVAs) to inspect and sample the asteroid material before returning to Earth. One option involves capturing an entire small (˜4-10 m diameter) near-Earth asteroid (NEA) inside a large inflatable bag. However, NASA is examining another option that entails retrieving a boulder (˜1-5 m) via robotic manipulators from the surface of a larger (˜100+ m) pre-characterized NEA. This option can leverage robotic mission data to help ensure success by targeting previously (or soon to be) well-characterized NEAs. For example, the data from the Hayabusa mission has been utilized to develop detailed mission designs that assess options and risks associated with proximity and surface operations. Hayabusa’s target NEA, Itokawa, has been identified as a valid target and is known to possess hundreds of appropriately sized boulders on its surface. Further robotic characterization of additional NEAs (e.g., Bennu and 1999 JU3) by NASA’s OSIRIS REx and JAXA’s Hayabusa 2 missions is planned to begin in 2018. The boulder option is an extremely large sample-return mission with the prospect of bringing back many tons of well-characterized asteroid material to the Earth-Moon system. The candidate boulder from the target NEA can be selected based on inputs from the world-wide science community, ensuring that the most scientifically interesting boulder be returned for subsequent sampling. This boulder option for NASA’s ARM can leverage knowledge of previously characterized NEAs from prior robotic missions, which provides more certainty of the target NEA

  3. The Spherical Brazil Nut Effect and its Significance to Asteroids

    Science.gov (United States)

    Perera, Viranga; Jackson, Alan P.; Asphaug, Erik; Ballouz, Ronald-Louis

    2015-11-01

    Asteroids are intriguing remnant objects from the early solar system. They can inform us on how planets formed, they could possibly impact the earth in the future, and they likely contain precious metals; for those reasons, there will be future exploration and mining space missions to them. Telescopic observations and spacecraft data have helped us understand basic properties such as their size, mass, spin rate, orbital elements, and their surface properties. However, their interior structures have remained elusive. In order to fully characterize the interiors of these bodies, seismic data will be necessary. However, we can infer their interior structures by combining several key factors that we know about them: 1). Past work has shown that asteroids between 150 m to 10 km in size are rubble-piles that are a collection of particles held together by gravity and possibly cohesion. 2). Asteroid surfaces show cratering that suggests that past impacts would have seismically shaken these bodies. 3). Spacecraft images show that some asteroids have large protruding boulders on their surfaces. A rubble-pile object made of particles of different sizes and that undergoes seismic shaking will experience granular flow. Specifically, a size sorting effect known as the Brazil Nut Effect will lead larger particles to move towards the surface while smaller particles will move downwards. Previous work has suggested that this effect could possibly explain not only why there are large boulders on the surfaces of some asteroids but also might suggest that the interior particles of these bodies would be organized by size. Previous works have conducted computer simulations and lab experiments; however, all the particle configurations used have been either cylindrical or rectangular boxes. In this work we present a spherical configuration of self-gravitating particles that is a better representation of asteroids. Our results indicate that while friction is not necessary for the Brazil Nut

  4. Approximate Equilibrium Shapes for Spinning, Gravitating Rubble Asteroids

    Science.gov (United States)

    Burns, Joseph A.; Sharma, I.; Jenkins, J. T.

    2007-10-01

    Approximate Equilibrium Shapes for Spinning, Gravitating Rubble Asteroids Joseph A. Burns, Ishan Sharma and James T. Jenkins Many asteroids are thought to be particle aggregates held together principally by self-gravity. Here we study those equilibrium shapes of spinning asteroids that are permitted for rubble piles. As in the case of spinning fluid masses, not all shapes may be compatible with a granular rheology. We take the asteroid to always be an ellipsoid with an interior modeled as a rigid-plastic, cohesion-less material. Using an approximate volume-averaged procedure, based on the classical method of moments, we investigate the dynamical process by which such objects may achieve equilibrium. First, to instill confidence in our approach, we have collapsed our dynamical approach to its statical limit to re-derive regions in spin-shape parameter space that allow equilibrium solutions to exist. Not surprisingly, our results duplicate static results reported by Holsapple (Icarus 154 [2001], 432; 172 [2004], 272) since the two sets of final equations match, although the formalisms to reach these expressions differ. We note that the approach applied here was obtained independently by I.S. in his Ph.D. dissertation (Cornell University, 2004); it provides a general, though approximate, framework that is amenable to systematic improvements and flexible enough to incorporate the dynamical effects of a changing shape, different rheologies and complex rotational histories. To demonstrate the power of our technique, we investigate the non-equilibrium dynamics of rigid-plastic, spinning, prolate asteroids to watch the simultaneous histories of shape and spin rate for rubble piles. We have succeeded in recovering most results of Richardson et al. (Icarus 173 [2004], 349), who obtained equilibrium shapes by studying numerically the passage into equilibrium of aggregates containing discrete, interacting, frictionless, spherical particles. Our mainly analytical approach aids

  5. Overview and Updated Status of the Asteroid Redirect Mission (ARM)

    Science.gov (United States)

    Abell, Paul; Mazanek, Daniel D.; Reeves, David M.; Chodas, Paul; Gates, Michele; Johnson, Lindley N.; Ticker, Ronald

    2016-10-01

    The National Aeronautics and Space Administration (NASA) is developing a mission to visit a large near-Earth asteroid (NEA), collect a multi-ton boulder and regolith samples from its surface, demonstrate a planetary defense technique known as the enhanced gravity tractor, and return the asteroidal material to a stable orbit around the Moon. Once returned to cislunar space in the mid-2020s, astronauts will explore the boulder and return to Earth with samples. This Asteroid Redirect Mission (ARM) is part of NASA's plan to advance the technologies, capabilities, and spaceflight experience needed for a human mission to the Martian system in the 2030s and other destinations, as well as provide other broader benefits. Subsequent human and robotic missions to the asteroidal material would also be facilitated by its return to cislunar space. Although ARM is primarily a capability demonstration mission (i.e., technologies and associated operations), there exist significant opportunities to advance our knowledge of small bodies in the synergistic areas of science, planetary defense, asteroidal resources and in-situ resource utilization (ISRU), and capability and technology demonstrations. Current plans are for the robotic mission to be launched in late 2021 with the crewed mission segment conducted using an Orion capsule via a Space Launch System rocket in 2026. In order to maximize the knowledge return from the mission, NASA is providing accommodations for payloads to be carried on the robotic segment of the mission and also organizing an ARM Investigation Team. The Investigation Team will be comprised of scientists, technologists, and other qualified and interested individuals from US industry, government, academia, and international institutions to help plan the implementation and execution of ARM. The presentation will provide a mission overview and the most recent update concerning the robotic and crewed segments of ARM, including the mission requirements, and potential

  6. The young Datura asteroid family. Spins, shapes, and population estimate

    Science.gov (United States)

    Vokrouhlický, D.; Pravec, P.; Durech, J.; Bolin, B.; Jedicke, R.; Kušnirák, P.; Galád, A.; Hornoch, K.; Kryszczyńska, A.; Colas, F.; Moskovitz, N.; Thirouin, A.; Nesvorný, D.

    2017-02-01

    Context. Asteroid families are the outcomes of disruption or cratering events on a size and energy scales that are not reproducible in laboratory experiments. Overall structure, as well as properties of individual members, in the old families could have been changed since their formation. Therefore young families preserve best the characteristics of the initial event. Aims: We study the most suitable known asteroid family with an age of less than 1 Myr, the Datura family. We aim (i) to obtain information about rotation state and shape of the largest members in the family; and (ii) to constrain its debiased population down to couple of hundreds of meters in size. Methods: We have analyzed the up-to-date catalog of orbital elements of main belt asteroids. We evaluated the detection efficiency of Catalina Sky Survey (CSS) in regard to detections of members in the Datura family, and we have used our photometric observations and lightcurve inversion methods to determine the rotation states and shapes of the largest members of the family. Results: We determined rotation periods of the seven largest members of the Datura family, and we also derived accurate mean absolute magnitudes for six of them. Except for the largest fragment (1270) Datura, the asteroids tend to have long rotation periods and large amplitude of the lightcurve, witnessing an elongated shape. For the four largest asteroids, our observations allow us to resolve rotation pole and a rough shape. All of them are prograde-rotating and have the latitude of the rotation pole >50°. Our search in orbital catalogs resulted in the discovery of many small, sub-kilometer members of the Datura family. Using the CSS detection efficiency, we inverted this information into the debiased population of Datura family members. We show that the mass and angular momentum content in small fragments is negligible compared to the largest fragment (1270) Datura. These findings may help to constrain the formation mechanism of the

  7. Moving an asteroid with electric solar wind sail

    Science.gov (United States)

    Merikallio, S.; Janhunen, P.

    2010-12-01

    The electric solar wind sail (E-Sail) is a new propulsion method for interplanetary travel which was invented in 2006 and is currently under development. The E-Sail uses charged tethers to extract momentum from the solar wind particles to obtain propulsive thrust. According to current estimates, the E-Sail is 2-3 orders of magnitude better than traditional propulsion methods (chemical rockets and ion engines) in terms of produced lifetime-integrated impulse per propulsion system mass. Here we analyze the problem of using the E-Sail for directly deflecting an Earth-threatening asteroid. The problem then culminates into how to attach the E-Sail device to the asteroid. We assess alternative attachment strategies, namely straightforward direct towing with a cable and the gravity tractor method which works for a wider variety of situations. We also consider possible techniques to scale up the E-Sail force beyond the baseline one Newton level to deal with more imminent or larger asteroid or cometary threats. As a baseline case we consider an asteroid of effective diameter of 140 m and mass of 3 million tons, which can be deflected with a baseline 1 N E-Sail within 10 years. With a 5 N E-Sail the deflection could be achieved in 5 years. Once developed, the E-Sail would appear to provide a safe and reasonably low-cost way of deflecting dangerous asteroids and other heavenly bodies in cases where the collision threat becomes known several years in advance.

  8. The geologic mapping of asteroid Vesta

    Science.gov (United States)

    Williams, D.; Yingst, A.; Garry, B.

    2014-07-01

    As part of NASA's Dawn mission [1,2] we conducted a geologic mapping campaign to provide a systematic, cartography-based initial characterization of the global and regional geology of asteroid Vesta. The goal of geological maps is to place observations of surface features into their stratigraphic context to develop a geologic history of the evolution of planetary surfaces. Geologic mapping reduces the complexity of heterogeneous planetary surfaces into comprehensible portions, defining and characterizing discrete material units based upon physical attributes related to the geologic processes that produced them, and enabling identification of the relative roles of various processes (impact cratering, tectonism, volcanism, erosion and deposition) in shaping planetary surfaces [3,4]. The Dawn Science Team produced cartographic products of Vesta from the Framing Camera images, including global mosaics as well as 15 regional quadrangles [5], which served as bases for the mapping. We oversaw the geologic mapping campaign during the Nominal Mission, including production of a global geologic map at scale 1:500,000 using images from the High Altitude Mapping Orbit [6] and 15 quadrangle geologic maps at scale 1:250,000 using images from the Low Altitude Mapping Orbit [7]. The goal was to support the Dawn Team by providing geologic and stratigraphic context of surface features and supporting the analysis of data from the Visible and Infrared Spectrometer (VIR) and the Gamma Ray and Neutron Detector (GRaND). Mapping was done using ArcGIS™ software, in which quadrangle mapping built on interpretations derived from the global geologic map but were updated and modified to take advantage of the highest spatial resolution data. Despite challenges (e.g., Vesta's highly sloped surface [8] deforms impact craters and produces mass movements that buries contacts), we were successfully able to map the whole surface of Vesta and identify a geologic history as represented in our maps and

  9. Capillary Action in a Crack on the Surface of Asteroids with an Application to 433 Eros

    CERN Document Server

    Jiang, Yu

    2016-01-01

    Some asteroids contain water ice, and a space mission landing on an asteroid may take liquid to the surface of the asteroid. Gas pressure is very weak on the surface of asteroids. Here we consider the capillary action in a crack on the surface of irregular asteroids. The crack is modelled as a capillary which has a fixed radius. An asteroid s irregular gravitational potential influences the height of the liquid in the capillary. The height of the liquid in the capillary on the surface of such asteroids is derived from the asteroid s irregular gravitational potential. Capillary mechanisms are expected to produce an inhomogeneaous distribution of emergent liquid on the surface. This result is applied to asteroid 433 Eros, which has an irregular, elongated, and concave shape. Two cases are considered 1) we calculate the height of the liquid in the capillary when the direction of the capillary is perpendicular to the local surface of the asteroid; 2) we calculate the height of the liquid in the capillary when the...

  10. Earth encounters as the origin of fresh surfaces on near-Earth asteroids.

    Science.gov (United States)

    Binzel, Richard P; Morbidelli, Alessandro; Merouane, Sihane; Demeo, Francesca E; Birlan, Mirel; Vernazza, Pierre; Thomas, Cristina A; Rivkin, Andrew S; Bus, Schelte J; Tokunaga, Alan T

    2010-01-21

    Telescopic measurements of asteroids' colours rarely match laboratory reflectance spectra of meteorites owing to a 'space weathering' process that rapidly reddens asteroid surfaces in less than 10(6) years. 'Unweathered' asteroids (those having spectra matching the most commonly falling ordinary chondrite meteorites), however, are seen among small bodies the orbits of which cross inside Mars and the Earth. Various explanations have been proposed for the origin of these fresh surface colours, ranging from collisions to planetary encounters. Less reddened asteroids seem to cross most deeply into the terrestrial planet region, strengthening the evidence for the planetary-encounter theory, but encounter details within 10(6) years remain to be shown. Here we report that asteroids displaying unweathered spectra (so-called 'Q-types') have experienced orbital intersections closer than the Earth-Moon distance within the past 5 x 10(5) years. These Q-type asteroids are not currently found among asteroids showing no evidence of recent close planetary encounters. Our results substantiate previous work: tidal stress, strong enough to disturb and expose unweathered surface grains, is the most likely dominant short-term asteroid resurfacing process. Although the seismology details are yet to be worked out, the identification of rapid physical processes that can produce both fresh and weathered asteroid surfaces resolves the decades-long puzzle of the difference in colour of asteroids and meteorites.

  11. M-class Asteroids: Soft Rock, Heavy Metal, Or None Of That Jazz?

    Science.gov (United States)

    Rivkin, Andrew S.

    2008-09-01

    M-class asteroids in the Tholen taxonomy have featureless spectra in the 0.3-1.0 micrometer region and moderate albedos. Taxonomic studies using reflectance spectra have long associated M-class asteroids with iron meteorites. Dozens of parent bodies are required by cosmochemists in order to generate the diversity seen in the iron meteorite population, representing both the disrupted cores of differentiated parent bodies as well as objects with more exotic histories. Unfortunately, the featureless spectrum of iron-nickel metal in the visible and near-IR can be matched by other mineralogies unrelated to iron meteorites. For instance, the primitive enstatite chondrites are also matches to M asteroids (Burbine et al. 2002). The past 20 years have led to increased recognition that the M asteroid class includes a diverse set of objects. Polarimetric, spectral, and radar observations in the 1980s and 1990s showed that at least some M asteroids were not iron-meteorite-like. In particular, observations by Jones et al. (1990), Rivkin et al. (1995), and Rivkin et al. (2000) found several M asteroids with absorptions near 3 micrometers, interpreted as hydrated minerals. This led to the proposal to separate those asteroids with bands into a new W class. Since 2000, new observations have been made by various workers in the near and mid-IR from the ground and with Spitzer. An increase in the sample size of radar-detected asteroids has provided additional insight into M and W asteroids. New meteorite classes have been delimited and characterized, some of which are of direct relevance to the M asteroid population. Discoveries of binary M-class asteroids have allowed densities to be measured Finally, the Rosetta spacecraft will fly by the M (W) asteroid 21 Lutetia in 2010. I will discuss the M/W asteroid class in the context of all of these new data. Thanks to the NASA PAST and PGG programs.

  12. Discovery of the first asteroid, Ceres historical studies in asteroid research

    CERN Document Server

    Cunningham, Clifford

    2016-01-01

    Based on extensive primary sources, many never previously translated into English, this is the definitive account of the origins of Ceres as it went from being classified as a new planet to reclassification as the first of a previously unknown group of celestial objects. Cunningham opens this critical moment of astronomical discovery to full modern analysis for the first time. This book includes all the voluminous correspondence, translated into English, between the astronomers of Europe about the startling discovery of Ceres by Piazzi in 1801. It covers the period up to March 1802, at which time Pallas was discovered. Also included are Piazzi's two monographs about Ceres, and the sections of two books dealing with Ceres, one by Johann Bode, the other by Johann Schroeter. The origin of the word 'asteroid' is explained, along with several chapters on the antecedents of the story going back to ancient Greek times. The formulation of Bode's Law is given, as are the details on the efforts of Baron von Zach to org...

  13. New insights into main belt asteroid collisional lifetimes

    Science.gov (United States)

    Henych, Tomas; Holsapple, Keith

    2016-10-01

    We are developing a new Monte Carlo code to study the collisional and spin evolution of main belt asteroids. A byproduct is information on asteroid lifetimes. We find new interpretations and values of those lifetimes.In the conventional approach, the "collisional lifetime" is measured by the time when an asteroid is struck by an impactor large enough to remove one-half of the target's mass. That event is called a catastrophic disruption (CD). From an assumed population of impactors and Poisson statistics, one can estimate the largest expected impactor to impact in a given time interval to get its expected collisional lifetime. However, our Monte Carlo simulations give lifetimes that are distinctly shorter. That raises questions about the basic definition of catastrophic disruption.During its presence in the main belt, many other asteroids of all sizes continually strike a target asteroid. Before the CD one happens, there are many small impacts, and a few less than but not equal to the CD one. Each impact erodes the target asteroid. Very commonly, it is eroded to a much smaller mass before some CD event. We will present examples.So what shall we define as its collisional lifetime? Should it be the time for which its mass is reduced to one-half of its original mass, irrespective of how that happened, perhaps from many impacts? Or when any single impact reduces its mass to one-half of its original mass? Or when a single impact reduces it to one-half of its current mass?We propose that collisional lifetime is defined as the time at which it reaches 50% of its original mass, from any combination of small and/or large events. We use cratering and ejecta scaling formulas (e.g. Holsapple, 1993, Housen and Holsapple, 2011) to calculate the eroded mass history of the target for a history of impactors and calculate the outcome of any impact using the current size. In the gravity regime, the eroded body is easier to disrupt. We will present our lifetime estimates and those of

  14. Growth of asteroids, planetary embryos and Kuiper belt objects by chondrule accretion

    CERN Document Server

    Johansen, Anders; Lacerda, Pedro; Bizzarro, Martin

    2015-01-01

    Chondrules are millimeter-sized spherules that dominate primitive meteorites (chondrites) originating from the asteroid belt. The incorporation of chondrules into asteroidal bodies must be an important step in planet formation, but the mechanism is not understood. We show that the main growth of asteroids can result from gas-drag-assisted accretion of chondrules. The largest planetesimals of a population with a characteristic radius of 100 km undergo run-away accretion of chondrules within ~3 Myr, forming planetary embryos up to Mars sizes along with smaller asteroids whose size distribution matches that of main belt asteroids. The aerodynamical accretion leads to size-sorting of chondrules consistent with chondrites. Accretion of mm-sized chondrules and ice particles drives the growth of planetesimals beyond the ice line as well, but the growth time increases above the disk life time outside of 25 AU. The contribution of direct planetesimal accretion to the growth of both asteroids and Kuiper belt objects is...

  15. Discovery, Observational Data and the Orbit of the Amor Group Asteroid 2010 BT3

    Science.gov (United States)

    Černis, K.; Zdanavičius, J.; Wlodarczyk, I.; Stonkutė, E.

    A project devoted to astrometric and photometric observations of asteroids at the Molėtai Observatory is described. One of its most important results is the discovery of the asteroid 2010 BT3 belonging to the Amor group of the near-Earth objects. The results of astrometric and photometric observations of the asteroid are presented. The brightness variations of the asteroid are found to be about 0.2 mag in R. The orbit of the asteroid was computed from 96 observations. This orbit, combined with the apparent brightness, gives the absolute magnitude 21.34 mag and the diameter between 160 m and 360 m, taking albedos of S-type and C-type asteroids, respectively.

  16. Effect of rotational disruption on the size-frequency distribution of the Main Belt asteroid population

    CERN Document Server

    Jacobson, Seth A; Rossi, Alessandro; Scheeres, Daniel J; Davis, Donald R

    2014-01-01

    The size distribution of small asteroids in the Main Belt is assumed to be determined by an equilibrium between the creation of new bodies out of the impact debris of larger asteroids and the destruction of small asteroids by collisions with smaller projectiles. However, for a diameter less than 6 km we find that YORP-induced rotational disruption significantly contributes to the erosion even exceeding the effects of collisional fragmentation. Including this additional grinding mechanism in a collision evolution model for the asteroid belt, we generate size-frequency distributions from either an accretional (Weidenschilling, 2011) or an "Asteroids were born big" (Morbidelli, 2009) initial size-frequency distribution that are consistent with observations reported in Gladman et al. (2009). Rotational disruption is a new mechanism that must be included in all future collisional evolution models of asteroids.

  17. Modeling the onset of photosynthesis after the Chicxulub asteroid impact

    CERN Document Server

    Perez, Noel; Martin, Osmel; Rojas, Reinaldo

    2012-01-01

    We do a preliminary modelling of the photosynthetic rates of phytoplankton at the very beginning of the Paleogene, just after the impact of the Chicxulub asteroid, which decisively contributed to the last known mass extinction of the Phanerozoic eon. We assume the worst possible scenario from the photobiological point of view: an already clear atmosphere with no ozone, as the timescale for soot and dust settling (years) is smaller than that of the full ozone regeneration (decades). Even in these conditions we show that most phytoplankton species would have had reasonable potential for photosynthesis in all the three main optical ocean water types. This modelling could help explain why the recovery of phytoplankton was relatively rapid after the huge environmental stress of that asteroid impact. In a more general scope, it also reminds us of the great resilience of the unicellular biosphere against huge environmental perturbations.

  18. Bounded relative orbits about asteroids for formation flying and applications

    Science.gov (United States)

    Baresi, Nicola; Scheeres, Daniel J.; Schaub, Hanspeter

    2016-06-01

    The relative motion about 4179 Toutatis is studied in order to investigate the feasibility of formation flying as an alternative concept for future asteroid exploration missions. In particular, the existence of quasi-frozen orbits about slowly rotating bodies allows us to compute families of periodic orbits in the body-fixed frame of the asteroid. Since these periodic orbits are of the center×center type, quasi-periodic invariant tori are calculated via fully numerical procedures and used to initialize spacecraft formations about the central body. Numerical simulations show that the resulting in-plane and out-of-plane relative trajectories remain bounded over long time spans; i.e., more than 30 days.

  19. Note about the impact possibilities of asteroid (99942) Apophis

    CERN Document Server

    Krolikowska, Malgorzata

    2010-01-01

    The Monte Carlo method of the nominal orbit clonning was applied to the case of 99942 Apophis, the asteroid from the Aten group. Calculations based on observations from the time interval of 2004 03 15 - 2008 01 09 have shown that the asteroid will pass near Earth in 2029 at the minimum distance of 5.921 \\pm 0.042 R_{Earth}, what implies that the likelihood that Apophis strikes the planet at 2036 April 13 increased to 4.5\\times 10^{-6} (from about 6\\times 10^{-7} previously announced by us in Paper~I (Krolikowska, Sitarski and Soltan, 2009, MNRAS 399, 1964). This value is identical with that given by Chesley, Baer, and Monet (2010, Icarus, in press).

  20. Asteroids and Dwarf Planets and How to Observe Them

    CERN Document Server

    Dymock, Roger

    2010-01-01

    ASTRONOMERS’ OBSERVING GUIDES provide up-to-date information for amateur astronomers who want to know all about what it is they are observing. This is the basis of the first part of the book. The second part details observing techniques for practical astronomers, working with a range of different instruments. ------------------------------------------------------------------------------------------------------ We live in a violent universe. The media constantly remind us of the possibility of an object suddenly appearing and hitting Earth. A hit by an asteroid is believed to have spelled the end of the dinosaurs. Such a collision by an object from space could cause another extinction event, if the object were large enough. And such objects are definitely out there. Often called “the vermin of the sky,” asteroids roam our Solar System often unseen. Many have been tracked, and their orbits calculated. But there are still many to be discovered and assessed. Many amateur astronomers are helping in this effo...

  1. Moon Search Algorithms for NASA's Dawn Mission to Asteroid Vesta

    CERN Document Server

    Memarsadeghi, Nargess; Skillman, David; McLean, Brian; Mutchler, Max; Carsenty, Uri; Palmer, Eric E; 10.1117/12.915564

    2013-01-01

    A moon or natural satellite is a celestial body that orbits a planetary body such as a planet, dwarf planet, or an asteroid. Scientists seek understanding the origin and evolution of our solar system by studying moons of these bodies. Additionally, searches for satellites of planetary bodies can be important to protect the safety of a spacecraft as it approaches or orbits a planetary body. If a satellite of a celestial body is found, the mass of that body can also be calculated once its orbit is determined. Ensuring the Dawn spacecraft's safety on its mission to the asteroid (4) Vesta primarily motivated the work of Dawn's Satellite Working Group (SWG) in summer of 2011. Dawn mission scientists and engineers utilized various computational tools and techniques for Vesta's satellite search. The objectives of this paper are to 1) introduce the natural satellite search problem, 2) present the computational challenges, approaches, and tools used when addressing this problem, and 3) describe applications of various...

  2. DIFFUSION CHARACTERS OF THE ORBITS IN THE ASTEROID MOTION

    Institute of Scientific and Technical Information of China (English)

    周礼勇; 孙义燧; 周济林

    2001-01-01

    A symplectic mapping is studied carefully. The exponential diffusion law in developed chaotic region and algebraic law in mixed region were observed. An area was found where the diffusion follows a logarithmic law. It is shown in the vicinity of an island,the logarithm of the escape time decreases linearily as the initial position moves away from the island. But when approaching close to the island, the escape time goes up very quickly,consistent with the superexponential stability of the invariant curve. When applied to the motion of asteroid, this mapping' s fixed points and their stabilities give an explanation of the distribution of asteroids. The diffusion velocities in 4: 3, 3: 2 and 2: 1 jovian resonances are also investigated.

  3. EXTREME AO OBSERVATIONS OF TWO TRIPLE ASTEROID SYSTEMS WITH SPHERE

    Energy Technology Data Exchange (ETDEWEB)

    Yang, B.; Wahhaj, Z.; Dumas, C.; Marsset, M. [European Southern Observatory, Santiago (Chile); Beauvalet, L. [National Observatory, Rio de Janeiro (Brazil); Marchis, F.; Nielsen, E. L. [Carl Sagan Center at the SETI Institute, Mountain View, CA (United States); Vachier, F., E-mail: byang@eso.org [Institut de Mécanique Céleste et de Calcul des Éphémérides, Paris (France)

    2016-04-01

    We present the discovery of a new satellite of asteroid (130) Elektra—S/2014 (130) 1—in differential imaging and in integral field spectroscopy data over multiple epochs obtained with Spectro-Polarimetric High-contrast Exoplanet Research/Very Large Telescope. This new (second) moonlet of Elektra is about 2 km across, on an eccentric orbit, and about 500 km away from the primary. For a comparative study, we also observed another triple asteroid system, (93) Minerva. For both systems, component-resolved reflectance spectra of the satellites and primary were obtained simultaneously. No significant spectral difference was observed between the satellites and the primary for either triple system. We find that the moonlets in both systems are more likely to have been created by sub-disruptive impacts as opposed to having been captured.

  4. Near-Earth Asteroids as Possible Parent Bodies of Meteor Streams

    Directory of Open Access Journals (Sweden)

    M.G. Sokolova

    2016-12-01

    Full Text Available The genetic relationship of meteor streams with near-Earth asteroids (NEAs is being actively studied. A genetic link with the asteroid is possible only for streams in which meteoroids have the geocentric speed smaller than 50 km/s, thereby meaning the proportionality of their orbits with the orbits of asteroids. To date, there are about 40 such orphan streams with unknown parent bodies. In the paper, NEA groups (Aten, Apollo, Amor, and Atira have been considered from the perspective of possible search for the parent bodies of meteor streams among them. The groups have been compared based on the following parameters: eccentricity of asteroid orbits, as well as size and chemical composition of asteroids. Currently, it is considered that the surface of asteroids with elongated orbits is subjected to temperature fall: it is heated in perihelion and cooled in aphelion. Due to small orbital periods around the Sun (about 2–4 years, this may lead to formation of meteoroid clusters. Therefore, comparison of asteroids by their orbit shape and physicochemical parameters enables us to distinguish between NEA groups of asteroids and the Apollo group as most probable candidates to search for the parent bodies of meteor streams among NEAs. Unfortunately, finding physicochemical parameters poses great difficulties, since they are only detectable for some asteroids. At the same time, it is impossible to study asteroids dynamics, evolution, and relation with other bodies of the Solar system, as well as to realistically assess the impact of NEAs and products of their disintegration collision with the Earth and to develop systems of anti-asteroid protection without knowing the following parameters of asteroids: mineralogical composition, density, size, and accurate mass.

  5. "Prospecting Asteroids: Indirect technique to estimate overall density and inner composition"

    Science.gov (United States)

    Such, Pamela

    2016-07-01

    Spectroscopic studies of asteroids make possible to obtain some information on their composition from the surface but say little about the innermost material, porosity and density of the object. In addition, spectroscopic observations are affected by the effects of "space weathering" produced by the bombardment of charged particles for certain materials that change their chemical structure, albedo and other physical properties, partly altering their chances of identification. Data such as the mass, size and density of the asteroids are essential at the time to propose space missions in order to determine the best candidates for space exploration and is of great importance to determine a priori any of them remotely from Earth. From many years ago its determined masses of largest asteroids studying the gravitational effects they have on smaller asteroids when they approach them (see Davis and Bender, 1977; Schubart and Matson, 1979; School et al 1987; Hoffman, 1989b, among others), but estimates of the masses of the smallest objects is limited to the effects that occur in extreme close encounters to other asteroids of similar size. This paper presents the results of a search for approaches of pair of asteroids that approximate distances less than 0.0004 UA (50,000 km) of each other in order to study their masses through the astrometric method and to estimate in a future their densities and internal composition. References Davis, D. R., and D. F. Bender. 1977. Asteroid mass determinations: search for futher encounter opportunities. Bull. Am. Astron. Soc. 9, 502-503. Hoffman, M. 1989b. Asteroid mass determination: Present situation and perspectives. In asteroids II (R. P. Binzel, T. Gehreis, and M. S. Matthews, Eds.), pp 228-239. Univ. Arizona Press, Tucson. School, H. L. D. Schmadel and S. Roser 1987. The mass of the asteroid (10) Hygiea derived from observations of (829) Academia. Astron. Astrophys. 179, 311-316. Schubart, J. And D. L. Matson 1979. Masses and

  6. Resistance forces during boulder extraction from an asteroid

    Science.gov (United States)

    Kulchitsky, Anton V.; Johnson, Jerome B.; Reeves, David M.

    2016-10-01

    Planning for NASA's Asteroid Redirect Mission (ARM) requires estimating the forces that appear during extraction of a boulder from the surface of an asteroid with unknown surface regolith properties. These forces are estimated for a vertical constant force or acceleration pull and a rolling, constant force, torque (peel) on a 4-m diameter spherical boulder using both analytic and discrete element method (DEM) models considering the effects of microgravity and regolith cohesion using Johnson-Kendall-Roberts (JKR) model. Estimates of the bulk asteroid regolith cohesion strength derived from lunar and asteroid regolith studies ranged from 25 Pa to 250 Pa. JKR cohesive forces at particle contacts depend on particle surface energy and effective curvature radius (particle size). DEM particle size dependent cohesion parameters are linked to estimated regolith cohesion strength by simulating shear and tension tests over a range of DEM particle surface energies resulting in the formulation of the dependence of particle surface energy as a function of cohesion strength and particle size. Maximum extraction forces occur for a vertical pull through the boulder center of mass with constant acceleration. Extraction force decreases for a constant force pull to 0.62pc S where S is the boulder surface area embedded in the regolith and pc is the cohesion strength of the regolith. Boulder extraction by peeling produces the smallest forces by up to more than a factor of 2, as the failure across the boulder surface increases progressively rather than being fully engaged as occurs during a vertical pull extraction. Variations between DEM and analytic results differed from 9% to 17% over the range of regolith cohesion values and peel extraction leverage.

  7. Radar Observations of Asteroids 64 Angelina and 69 Hesperia

    Science.gov (United States)

    Shepard, Michael K.; Clark, B. E.; Ockert-Bell, M.; Nolan, M. C.; Howell, E. S.; Magri, C.; Benner, L. A. M.; Giorgini, J. D.

    2010-10-01

    Using the S-band radar at Arecibo Observatory, we observed the E-class asteroid 64 Angelina and the M-class asteroid 69 Hesperia. We obtained a single run on Angelina on 31 Jan 2010 with a signal-to-noise (SNR) of 10. We find its circular polarization ratio (SC/OC) to be muc = 0.8 +/- 0.1, tied with 434 Hungaria for the highest value measured for any main-belt asteroid (Shepard et al. 195, 220-225, 2008). This is consistent with the high polarization ratios observed for the E-class asteroids in general (Benner et al. Icarus 198, 294-304, 2008). Our estimate of the echo's bandwidth is B = 35 +/- 5 Hz. This is inconsistent with a published diameter of 60 km (Morrison and Chapman, ApJ 204, 934-939, 1976) and published rotation pole (lambda/beta 138/+31 deg, uncertainties +/- 10 deg, Shevchenko et al. PSS 51, 525-532, 2003). Either the pole is significantly different, the diameter is smaller, or some combination of these. We obtained two runs on 69 Hesperia on 3 Feb 2010 with a total SNR of 24. We estimate a bandwidth of B = 440 +/- 40 Hz that is 75% of the expected value based on the published diameter (IRAS, 138 km) and pole direction (lambda/beta 73 / -45 deg, Torppa et al. Icarus 164, 346-383, 2003). We estimate a radar albedo of 0.4 for the first run, placing it in the high-metal M-class (Mm) class defined by Shepard et al. (Icarus, 208, 221-237, 2010). Acknowledgements: This work was funded by NSF grant AST-0908098 to MKS and AST-0908217 to BEC.

  8. The OSIRIS-REx Sample Return Mission from Asteroid Bennu

    Science.gov (United States)

    Lauretta, Dante; Clark, Benton

    2016-07-01

    The primary objective of the Origins, Spectral Interpretation, Resource Identification, and Security‒Regolith Explorer (OSIRIS-REx) mission is to return and analyze a sample of pristine regolith from asteroid 101955 Bennu, a primitive carbonaceous asteroid and also a potentially hazardous near-Earth object. Returned samples are expected to contain primitive ancient Solar System materials formed in planetary, nebular, interstellar, and circumstellar environments. In addition, the OSIRIS-REx mission will obtain valuable information on sample context by imaging the sample site; characterize its global geology; map global chemistry and mineralogy; investigate dynamic history by measuring the Yarkovsky effect; and advance asteroid astronomy by characterizing surface properties for direct comparison with ground-based telescopic observations of the entire asteroid population. Following launch in September 2016, the spacecraft will encounter Bennu in August 2018, then embark on a systematic study of geophysical and morphological characteristics of this ~500-meter-diameter object, including a systematic search for satellites and plumes. For determination of context, composition, and sampleability of various candidate sites, advanced instruments for remote global observations include OVIRS (visible to mid-IR spectrometric mapper), OTES (mid- to far-IR mineral and thermal emission mapper), OLA (mapping laser altimeter), and a suite of scientific cameras (OCAMS) with sub-cm pixel size from low-altitude Reconnaissance passes. A unique sample acquisition mechanism (SAM) capable of collecting up to one liter of regolith under ideal conditions (abundant small particulates tested in ground tests, and also on reduced-gravity airplane flights, to evaluate collection efficiency for various surfaces. Special cleaning techniques and contamination monitoring with in-flight witness plates are employed to assure a pristine sample. In September 2023, the entire TAGSAM end-effector stowed

  9. Linking Scarce Asteroid Astrometry At Discovery And Over Apparitions

    Science.gov (United States)

    Granvik, Mikael; Muinonen, K.

    2007-10-01

    Currently about 10% of all asteroid astrometry reported to the Minor Planet Center (MPC) belong to single-night observation sets. Similarly, roughly 10-15% of the asteroids that have received a designation by the MPC have been observed only during one apparition. Due to the scarce astrometry, which leads to large ephemeris uncertainties, most of the underlying asteroids have essentially been lost. However, by linking a few of these scarce data sets, the underlying object can be recovered. Due to challenges such as short observational time spans, a small amount of observed positions, astrometric uncertainties, long linking intervals, parallax, and --- particularly in the future --- massive amounts of data, the linking task is highly non-trivial. We have developed novel linking methods capable of dealing with the challenges posed both by the short-term linking of single-night astrometry and by the long-term linking of single-apparition astrometry. The methods are based on statistical inversion of asteroid astrometry for the probability-density functions of the orbital elements. Through the use of dimensionality-reduction techniques and efficient data structures the methods scale as Ο(n log n), where n is the number of included observation sets. The methods are thus suitable for future large-scale surveys which anticipate a substantial increase in the astrometric data rate. We will present the methods and the key techniques used, with an emphasis on the new long-term linking method. We will also show results obtained for both simulated and real astrometry. The focus will be on the results obtained when searching for linkages among the tens of thousands of real observation sets spanning less than two days.

  10. Exploring Exogenic Sources for the Olivine on Asteroid (4) Vesta

    OpenAIRE

    Corre, Lucille Le; Reddy, Vishnu; Sanchez, Juan A.; Dunn, Tasha; Cloutis, Edward A.; Izawa, Matthew R. M.; Mann, Paul; Nathues, Andreas

    2015-01-01

    The detection of olivine on Vesta is interesting because it may provide critical insights into planetary differentiation early in our Solar System's history. Ground-based and Hubble Space Telescope (HST) observations of asteroid (4) Vesta have suggested the presence of olivine on the surface. These observations were reinforced by the discovery of olivine-rich HED meteorites from Vesta in recent years. However, analysis of data from NASA's Dawn spacecraft has shown that this olivine-bearing un...

  11. Physical properties of Aten, Apollo and Amor asteroids

    Science.gov (United States)

    Mcfadden, Lucy-Ann; Tholen, David J.; Veeder, Glenn J.

    1989-01-01

    Data available on the physical properties of a group of planet-crossing asteroids, the Aten, Apollo, and Amor objects (AAAO) (include data on the taxonomy, mineralogical surface composition, diameter, rotation rate, shape, and surface texture) are presented together with the type of observations used for obtaining these data. These data show that the population of the AAAO is diverse in all of their physical characteristics. This diversity implies that the AAAO come from multiple sources and had different evolutionary histories.

  12. SPH-based simulation of multi-material asteroid collisions

    CERN Document Server

    Maindl, Thomas I; Speith, Roland; Süli, Áron; Forgács-Dajka, Emese; Dvorak, Rudolf

    2013-01-01

    We give a brief introduction to smoothed particle hydrodynamics methods for continuum mechanics. Specifically, we present our 3D SPH code to simulate and analyze collisions of asteroids consisting of two types of material: basaltic rock and ice. We consider effects like brittle failure, fragmentation, and merging in different impact scenarios. After validating our code against previously published results we present first collision results based on measured values for the Weibull flaw distribution parameters of basalt.

  13. Are There Meteors Originated from Near Earth Asteroid (25143) Itokawa?

    CERN Document Server

    Ohtsuka, K; Abe, M; Yano, H; Watanabe, J

    2008-01-01

    As a result of a survey of Itokawid meteors (i.e., meteors originated from Near Earth Asteroid (25143) Itokawa = 1998SF36), from among the multi-station optical meteor orbit data of ~15000 orbits, and applying the D-criteria, we could find five Itokawid meteor candidates. We also analyzed corresponding mineral materials of the Itokawid candidates through their trajectory and atmospheric data. We conclude, on the basis of our investigation, that the fireball, MORP172, is the strongest Itokawid candidate.

  14. A photometric search for activity among asteroids and Centaurs

    Science.gov (United States)

    Sosa Oyarzabal, A.; Mammana, L.; Fernández, J. A.

    2014-07-01

    We present the first results of a long-term observational campaign focused on the detection of activity in selected asteroids and centaurs. Our observational targets are near-Earth asteroids in cometary orbits (cf. [2]), the so called ''main-belt comets'' or ''active asteroids'' (well-known objects as well as potential candidates), and bright centaurs with good orbits, all close to their perihelion passages. In those objects with a former detection of activity, our aim is to contribute to a better physical knowledge of them, and determine, for instance, if the observed activity is transient or permanent. To achieve our goals, we analyzed CCD-filtered images of each observable target acquired with the 2.15-m telescope ''Jorge Sahade'' at CASLEO (San Juan, Argentina), during two runs of three consecutive nights each (during August 2013 and January 2014, respectively). Our study will be completed by future runs with the same instrumentation already assigned to our campaign. As preliminary results, we observed activity in the main-belt comets P/2013 P5 (PANSTARRS) and 133P/(7968) Elst-Pizarro. We also observed the main-belt comet (596) Scheila, which showed an unequivocally stellar appearance. We observed the main-belt comet candidate (3646) Aduatiques (cf. [1]), and noticed in this object a curious feature whose connection to some kind of activity is not well determined yet. We also observed the near-Earth asteroid in cometary orbit 2006 XL_5 (cf. [3]), and the centaurs (281371) 2008 FC_{76}, (332685) 2009 HH_{36}), (382004) 2010 RM_{64}, 2010 XZ_{78}, and 2011 UR_{402}. We have not detected activity in these objects, but an improved analysis is still in progress. %Corresponding author: Andrea Sosa (asosa@fisica.edu.uy)

  15. Asteroid phase curves from Lowell observatory photometric database

    Directory of Open Access Journals (Sweden)

    D. A. Oszkiewicz

    2011-09-01

    Full Text Available We present results obtained from processing large photometric data base. We make use of low-precision (generally rounded to 0.1 mag and low-accuracy (rms magnitude uncertainties of ±0.2 to 0.3 mag data obtained from the Minor Planet Center and modified at Lowell Observatory. We explore first correlations between slope parameter(s and albedo, and second distributions of slope parameter(s in asteroid families and taxa.

  16. Rotational Period of Three Main-belt Asteroids

    Science.gov (United States)

    Ferrro, Andrea

    2017-04-01

    CCD photometric observations of three main-belt asteroids were made to find the synodic period and amplitude of their lightcurves: 1264 Letaba, P = 33.27 ± 0.01 h, A = 0.15 mag; 2407 Haug, P = 6.162 ± 0.002 h, A = 0.32 mag; and 5464 Weller, P = 3.288 ± 0.002 h, A = 0.35 mag.

  17. Diffusion in a Symplectic Map with Application to Asteroid Motion

    Institute of Scientific and Technical Information of China (English)

    ZHOU Li-Yong; SUN Yi-Sui; ZHOU Ji-Lin

    2000-01-01

    In studying a 2-dimensional symplectic map, the exponential law and algebraic law are observed in the diffusion of orbits in the phase space. The diffusion time in the vicinity of an island is investigated carefully and a logarithm law is found for the first time. The distribution of asteroids in the main belt and the diffusion velocities in 3:2 nd 4:3 resonances are discussed using this map.

  18. Earth resonant gravity assists for asteroid retrieval missions

    OpenAIRE

    Sanchez, J. P.; E. M. Alessi; D. G. Yarnoz; McInnes, C.R.

    2013-01-01

    Asteroids and comets are of strategic importance for science in an effort to uncover the formation, evolution and composition of the Solar System. Near-Earth objects (NEOs) are of particular interest because of their accessibility from Earth, but also because of their speculated wealth of material resources. The possibility of retrieving entire NEOs from accessible heliocentric orbits and moving them into the Earth’s neighbourhood is today a credible possibility considered by NASA, within its...

  19. Asteroid Lightcurve Analysis at Elephant Head Observatory: 2013 August- October

    Science.gov (United States)

    Alkema, Michael S.

    2014-01-01

    Photometric observations of two main-belt asteroids, 541 Deborah and 1468 Zomba, were made from Elephant Head Observatory during 2013 August to October. The period and amplitude results are, respectively, P = 29.368 ± 0.005 h, A = 0.10 ± 0.01 mag; P = 2.773 ± 0.001 h, A = 0.34 ± 0.02 mag.

  20. Rotation Period Determination of Four Main-belt Asteroids

    Science.gov (United States)

    Ferrero, Andrea

    2016-10-01

    Observations of four main-belt asteroids (MBA) revealed the following rotation periods and lightcurve amplitudes: 3861 Lorenz, P = 11.91 ± 0.01 h, A = 0.28 mag; 6173 Jimwestphal P = 2.908 ± 0.001 h, A = 0.41 mag; 10259 Osipovyurij, P = 6.356 ± 0.001 h, A = 0.30 mag; 29470 Higgs, P = 36.31 ± 0.01 h, A = 0.48 mag.

  1. The mineralogy of ordinary chondrites and implications for asteroid spectrophotometry

    Science.gov (United States)

    Mcsween, Harry Y., Jr.; Bennett, Marvin E., III; Jarosewich, Eugene

    1991-01-01

    Published data from bulk chemical analyses of 94 ordinary chondrites are compiled in a table of normative mineralogy and discussed in detail. Significant variations in olivine, pyroxene, and metal abundance ratios are found within each chondrite class and attributed to redox processes superimposed on initial differences in metal/silicate ratios. The use of the diagrams constructed here to predict the mineralogic characteristics of asteroids on the basis of spectrophotometric observations is suggested.

  2. The OSIRIS-REx Asteroid Sample Return Mission Operations Design

    Science.gov (United States)

    Gal-Edd, Jonathan S.; Cheuvront, Allan

    2015-01-01

    OSIRIS-REx is an acronym that captures the scientific objectives: Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer. OSIRIS-REx will thoroughly characterize near-Earth asteroid Bennu (Previously known as 1019551999 RQ36). The OSIRIS-REx Asteroid Sample Return Mission delivers its science using five instruments and radio science along with the Touch-And-Go Sample Acquisition Mechanism (TAGSAM). All of the instruments and data analysis techniques have direct heritage from flown planetary missions. The OSIRIS-REx mission employs a methodical, phased approach to ensure success in meeting the mission's science requirements. OSIRIS-REx launches in September 2016, with a backup launch period occurring one year later. Sampling occurs in 2019. The departure burn from Bennu occurs in March 2021. On September 24, 2023, the Sample Return Capsule (SRC) lands at the Utah Test and Training Range (UTTR). Stardust heritage procedures are followed to transport the SRC to Johnson Space Center, where the samples are removed and delivered to the OSIRIS-REx curation facility. After a six-month preliminary examination period the mission will produce a catalog of the returned sample, allowing the worldwide community to request samples for detailed analysis. Traveling and returning a sample from an Asteroid that has not been explored before requires unique operations consideration. The Design Reference Mission (DRM) ties together spacecraft, instrument and operations scenarios. Asteroid Touch and Go (TAG) has various options varying from ground only to fully automated (natural feature tracking). Spacecraft constraints such as thermo and high gain antenna pointing impact the timeline. The mission is sensitive to navigation errors, so a late command update has been implemented. The project implemented lessons learned from other "small body" missions. The key lesson learned was 'expect the unexpected' and implement planning tools early in the lifecycle

  3. Quantifying the lack of differentiated material amongst asteroid families

    Science.gov (United States)

    Jacobson, Seth A.; Morbidelli, Alessandro

    2016-10-01

    Asteroid families are created during catastrophic and cratering events on parent bodies. Family identification and parent body reconstruction has been a focus of a number of prior works (e.g. Tanga et al. 1999, Durda et al. 2007, Broz et al. 2003). These works used identified family members from dynamical hierarchical clustering methods to estimate family size distributions. From these size distributions parent body masses can be estimated. The asteroid family parent body mass is a lower limit on the accreted planetesimal mass, since it could have been a fragment of some larger body. Different models of planetesimal accretion make different predictions for the size at which significant melting and differentiation should occur. Here, we test these models by comparing the lower limit on the accreted planetesimal mass to the amount of expected exposed crust, mantle and core material. The fraction of mass in the largest remnant compared to the parent body mass can differentiate between catastrophic and cratering events as well as provide an assessment for the minimum exposed depth of the parent body. We make upper limit estimates on the amount of differentiated mass contained in each family using spectroscopic and color surveys have become complete for V-type and A-type asteroids at relevant sizes. We compare these masses with those expected from totally and partially differentiated bodies.

  4. Triplicity and Physical Characteristics of Asteroid (216) Kleopatra

    CERN Document Server

    Descamps, Pascal; Berthier, J; Emery, J P; Duchêne, G; de Pater, I; Wong, M H; Lim, L; Hammel, H B; Vachier, F; Wiggins, P; Teng-Chuen-Yu, J -P; Peyrot, A; Pollock, J; Assafin, M; Vieira-Martins, R; Camargo, J I B; Braga-Ribas, F; Macomber, B

    2010-01-01

    To take full advantage of the September 2008 opposition passage of the M-type asteroid (216) Kleopatra, we have used near-infrared adaptive optics (AO) imaging with the W.M. Keck II telescope to capture unprecedented high resolution images of this unusual asteroid. Our AO observations with the W.M. Keck II telescope, combined with Spitzer/IRS spectroscopic observations and past stellar occultations, confirm the value of its IRAS radiometric radius of 67.5 km as well as its dog-bone shape suggested by earlier radar observations. Our Keck AO observations revealed the presence of two small satellites in orbit about Kleopatra (see Marchis et al., 2008). Accurate measurements of the satellite orbits over a full month enabled us to determine the total mass of the system to be 4.64+/-0.02 10^18 Kg. This translates into a bulk density of 3.6 +/-0.4 g/cm3, which implies a macroscopic porosity for Kleopatra of ~ 30-50%, typical of a rubble-pile asteroid. From these physical characteristics we measured its specific angu...

  5. Thermal conductivity determination of cometary and asteroid material analogues

    Science.gov (United States)

    Banaszkiewicz, M.; Seweryn, K.; Wawrzaszek, R.

    Measurements of physical properties of surface and subsurface layers of planetary bodies often provide important information about the structure of the medium and processes that occur there Thermal properties of cometary nuclues subsurface material are crucial in determining the heat and gas transport Similarly asteroid s regolith is a buffering zone in heat transfer from to surface to from interior of a body There are space experiments planned to perform temperature and thermal conductivity measurements on a comet ROSETTA and one can easily foresee such measurements carried out by future robotic missions on Mars planetary satellites and asteroids In the paper we present the results of measurements carried out with a new type of thermal sensors The elementary cylindrical sensor is made of platinum wire resistance thermometer and isotan wire heating element that can operate independently By choosing these materials the problems of temperature measurement calibration and constant heating power are resolved We confront the results of measurements made for a number of sensors combined into a long cylinder in delrin basalt ice-dust mixture comet analogue and regolith-like material with models and show that agreement is very good Therefore we can recommend both the sensors and the method of data interpretation for the thermal conductivity determination as very useful tools in future space missions and in laboratory experiments on cometary and asteroid material analogues

  6. Asteroid Rendezvous Mission Design Using Multiobjective Particle Swarm Optimization

    Directory of Open Access Journals (Sweden)

    Ya-zhong Luo

    2014-01-01

    Full Text Available A new preliminary trajectory design method for asteroid rendezvous mission using multiobjective optimization techniques is proposed. This method can overcome the disadvantages of the widely employed Pork-Chop method. The multiobjective integrated launch window and multi-impulse transfer trajectory design model is formulated, which employes minimum-fuel cost and minimum-time transfer as two objective functions. The multiobjective particle swarm optimization (MOPSO is employed to locate the Pareto solution. The optimization results of two different asteroid mission designs show that the proposed approach can effectively and efficiently demonstrate the relations among the mission characteristic parameters such as launch time, transfer time, propellant cost, and number of maneuvers, which will provide very useful reference for practical asteroid mission design. Compared with the PCP method, the proposed approach is demonstrated to be able to provide much more easily used results, obtain better propellant-optimal solutions, and have much better efficiency. The MOPSO shows a very competitive performance with respect to the NSGA-II and the SPEA-II; besides a proposed boundary constraint optimization strategy is testified to be able to improve its performance.

  7. Asteroid Perturbations and Mass Determination for the ASTROD Space Mission

    CERN Document Server

    Tang, C J; Tang, Chien-Jen; Ni, Wei-Tou

    2004-01-01

    Due to the high-precision nature of the ASTROD (Astrodynamical Space Test of Relativity using Optical Devices) mission concept, the asteroid perturbations on the ASTROD spacecraft is crucial. These perturbations need to be modelled and determined together with relativistic effects and other solar-system parameters. In a previous investigation (Su et al., Planetary and Space Science, 47, 339-43[1999]), we used the mass estimation of Ceres, Pallas and Vesta in the literature to calculate their perturbations on the ASTROD spacecraft. Recently, we established an ephemeris framework (CGC 1) including the 3 big asteroids and used this ephemeris framework to simulate the determination of their masses together with other solar-system parameters and relativistic-gravity parameters. In this paper, we extend the CGC 1 to CGC 2 ephemeris framework to include 492 asteroids (with diameter > 65 km) . We then use CGC 2 to simulate the determination of ten parameters -- the masses of Ceres, Pallas and Vesta, the six average d...

  8. Photometric Analysis of Asteroid (2867) Steins from Rosetta OSIRIS Images

    Science.gov (United States)

    La Forgia, F.; Magrin, S.; Bertini, I.; Lazzarin, M.; Pajola, M.; Barbieri, C.

    We present a method for analyzing the reflectance properties of atmosphereless bodies as asteroids and comet nuclei. The method is self-consistent, independent of the shape model of the object and can be easily applied for any space mission target. We used it for the E-type Main Belt asteroid (2867) Steins, observed from the OSIRIS-WAC camera onboard Rosetta spacecraft during a close approach on September 5, 2008. We investigate the reflectance dependence on phase angle which is interpreted in terms of the Hapke's theory of bidirectional reflectance. A deeper analysis allows to obtain an estimate of the typical size of the regolith grains. Steins regolith layer seems to be made of large, highly scattering iron-poor opaque silicate particles. The macroscopic roughness, probably influenced by the global irregular shape, appears fairly high, comparable with radar measurements of other E-type asteroids. Assuming an enstatite composition, we estimated a grain size of about 30-130 mu m and we noticed a correlation between grain size and wavelength, suggesting the existence of a grain size distribution, as expected from real surfaces. The comparison with more accurate calculations (Spjuth \\textit{et al.}, 2009) shows that our simplified method is robust and reliable for a preliminary and shape-independent analysis of the reflectance properties of atmosphereless bodies.

  9. Near Earth Asteroid Scout Thrust and Torque Model

    Science.gov (United States)

    Heaton, Andrew; Ahmad, Naeem; Miller, Kyle

    2017-01-01

    The Near Earth Asteroid (NEA) Scout is a solar sail mission whose objective is to scout at least one Near Earth Asteroid in preparation for manned missions to asteroids. NEA Scout will use a solar sail as the primary means of propulsion. Thus it is important for mission planning to accurately characterize the thrust of the sail. Additionally, the solar sail creates a relatively large solar disturbance torque that must be mitigated. For early mission design studies a flat plate model of the solar sail with a fixed center of pressure was adequate, but as mission concepts and the sail design matured, greater fidelity was required. Here we discuss the progress to a three-dimensional sail model that includes the effects of tension and thermal deformation that has been derived from a large structural Finite Element Model (FEM) developed by the Langley Research Center. We have found that the deformed sail membrane affects torque relatively much more than thrust. We have also found that other than uncertainty over the precise shape, the effect of small (approximately millimeter scale) wrinkles on the diffusivity of the sail is the leading remaining source of uncertainty. We demonstrate that millimeter-scale wrinkles can be modeled analytically as a change in the fraction of specular reflection. Finally we discuss the implications of these results for the NEA Scout mission.

  10. An integrated view of asteroid regeneration: tissues, cells and molecules.

    Science.gov (United States)

    Ben Khadra, Yousra; Sugni, Michela; Ferrario, Cinzia; Bonasoro, Francesco; Varela Coelho, Ana; Martinez, Pedro; Candia Carnevali, Maria Daniela

    2017-03-22

    The potential for repairing and replacing cells, tissues, organs and body parts is considered a primitive attribute of life shared by all the organisms, even though it may be expressed to a different extent and which is essential for the survival of both individual and whole species. The ability to regenerate is particularly evident and widespread within invertebrates. In spite of the wide availability of experimental models, regeneration has been comprehensively explored in only a few animal systems (i.e., hydrozoans, planarians, urodeles) leaving many other animal groups unexplored. The regenerative potential finds its maximum expression in echinoderms. Among echinoderm classes, asteroids offer an impressive range of experimental models in which to study arm regeneration at different levels. Many studies have been recently carried out in order to understand the regenerative mechanisms in asteroids and the overall morphological processes have been well documented in different starfish species, such as Asterias rubens, Leptasterias hexactis and Echinaster sepositus. In contrast, very little is known about the molecular mechanisms that control regeneration development and patterning in these models. The origin and the fate of cells involved in the regenerative process remain a matter of debate and clear insights will require the use of complementary molecular and proteomic approaches to study this problem. Here, we review the current knowledge regarding the cellular, proteomic and molecular aspects of asteroid regeneration.

  11. Thermophysical modeling of Didymos' moon for the Asteroid Impact Mission

    Science.gov (United States)

    Pelivan, Ivanka; Drube, Line; Kührt, Ekkehard; Helbert, Jörn; Biele, Jens; Maibaum, Michael; Cozzoni, Barbara; Lommatsch, Valentina

    2017-04-01

    Although typically less resolved through observations, the secondary in a binary system of asteroids is an interesting target for space missions such as the Asteroid Impact Mission. Estimates of the surface temperature distribution are important for mission design. Based on known, assumed and derived physical properties, a thermophysical model of the smaller body in the 65803 Didymos system is established. Because of the unknown thermal inertia, a parameter study has been carried out for a thermal inertia range of Γ = 50 -1000 J m-2 K-1 s-1/2. Results are presented for the minimum and maximum values of this range and a likely value of Γ = 500 J m-2 K-1 s-1/2. The parameter study extends from the unshadowed to the eclipsed case where shadowing through the primary is simulated in a simplified manner assuming that the orbit of the moon lies in the equatorial plane of the primary with its z-axis normal to this plane. Results from this study are used to investigate performance for instruments foreseen for the Asteroid Impact Mission. Preliminary results are obtained for the signal-to-noise ratio of a proposed thermal infrared imager. Furthermore, MASCOT-2 Lander thermal survivability has been investigated for several possible landing sites and specific settings.

  12. The spherical Brazil Nut Effect and its significance to asteroids

    CERN Document Server

    Perera, Viranga; Asphaug, Erik; Ballouz, Ronald-Louis

    2016-01-01

    Many asteroids are likely rubble-piles that are a collection of smaller objects held together by gravity and possibly cohesion. These asteroids are seismically shaken by impacts, which leads to excitation of their constituent particles. As a result it has been suggested that their surfaces and sub-surface interiors may be governed by a size sorting mechanism known as the Brazil Nut Effect. We study the behavior of a model asteroid that is a spherical, self-gravitating aggregate with a binary size-distribution of particles under the action of applied seismic shaking. We find that above a seismic threshold, larger particles rise to the surface when friction is present, in agreement with previous studies that focussed on cylindrical and rectangular box configurations. Unlike previous works we also find that size sorting takes place even with zero friction, though the presence of friction does aid the sorting process above the seismic threshold. Additionally we find that while strong size sorting can take place n...

  13. Asteroid fragmentation approaches for modeling atmospheric energy deposition

    Science.gov (United States)

    Register, Paul J.; Mathias, Donovan L.; Wheeler, Lorien F.

    2017-03-01

    During asteroid entry, energy is deposited in the atmosphere through thermal ablation and momentum-loss due to aerodynamic drag. Analytic models of asteroid entry and breakup physics are used to compute the energy deposition, which can then be compared against measured light curves and used to estimate ground damage due to airburst events. This work assesses and compares energy deposition results from four existing approaches to asteroid breakup modeling, and presents a new model that combines key elements of those approaches. The existing approaches considered include a liquid drop or "pancake" model where the object is treated as a single deforming body, and a set of discrete fragment models where the object breaks progressively into individual fragments. The new model incorporates both independent fragments and aggregate debris clouds to represent a broader range of fragmentation behaviors and reproduce more detailed light curve features. All five models are used to estimate the energy deposition rate versus altitude for the Chelyabinsk meteor impact, and results are compared with an observationally derived energy deposition curve. Comparisons show that four of the five approaches are able to match the overall observed energy deposition profile, but the features of the combined model are needed to better replicate both the primary and secondary peaks of the Chelyabinsk curve.

  14. Simultaneous Linear and Circular Optical Polarimetry of Asteroid (4) Vesta

    CERN Document Server

    Wiktorowicz, Sloane J

    2014-01-01

    From a single, 3.8-hour observation of asteroid (4) Vesta at $13.7^\\circ$ phase angle with the POLISH2 polarimeter at the Lick Observatory Shane 3-m telescope, we confirm rotational modulation of linear polarization in $B$ and $V$ bands. We measure the peak-to-peak modulation in degree of linear polarization to be $\\Delta P = (294 \\pm 35) \\times 10^{-6}$ (ppm) and time-averaged $\\Delta P / P = 0.0577 \\pm 0.0069$. After rotating the plane of linear polarization to the scattering plane, asteroidal rotational modulation is detected with $12 \\sigma$ confidence and observed solely in Stokes $Q/I$. POLISH2 simultaneously measures Stokes $I$, $Q$, $U$ (linear polarization), and $V$ (circular polarization), but we detect no significant circular polarization with a $1 \\sigma$ upper limit of 140 ppm in $B$ band. Circular polarization is expected to arise from multiple scattering of sunlight by rough surfaces, and it has previously been detected in nearly all other classes of Solar System bodies save asteroids. Subseque...

  15. Initial sizes of planetesimals and accretion of the asteroids

    Science.gov (United States)

    Weidenschilling, S. J.

    2011-08-01

    The present size frequency distribution (SFD) of bodies in the asteroid belt appears to have preserved some record of the primordial population, with an excess of bodies of diameter D ˜ 100 km relative to a simple power law. The survival of Vesta's basaltic crust also implies that the early SFD had a shallow slope in the range ˜10-100 km. (Morbidelli, A., Bottke, W.F., Nesvorny, D., Levison, H.F. [2009]. Icarus 204, 558-573) were unable to produce these features by accretion from an initial population of km-sized planetesimals. They concluded that bodies with sizes in the range ˜100-1000 km and a SFD similar to the current population were produced directly from solid particles of sub-meter scale, without experiencing accretion through intermediate sizes. We present results of new accretion simulations in the primordial asteroid region. The requisite SFD can be produced from an initial population of planetesimals of sizes ≲0.1 km, smaller than the usual assumption of km-sized bodies. The bump at D ˜ 100 km is produced by a transition from dispersion-dominated runaway growth to a regime dominated by Keplerian shear, before the formation of large protoplanetary embryos. Thus, accretion of the asteroids from an initial population of small (sub-km) planetesimals cannot be ruled out.

  16. Adapted G-mode Clustering Method applied to Asteroid Taxonomy

    Science.gov (United States)

    Hasselmann, Pedro H.; Carvano, Jorge M.; Lazzaro, D.

    2013-11-01

    The original G-mode was a clustering method developed by A. I. Gavrishin in the late 60's for geochemical classification of rocks, but was also applied to asteroid photometry, cosmic rays, lunar sample and planetary science spectroscopy data. In this work, we used an adapted version to classify the asteroid photometry from SDSS Moving Objects Catalog. The method works by identifying normal distributions in a multidimensional space of variables. The identification starts by locating a set of points with smallest mutual distance in the sample, which is a problem when data is not planar. Here we present a modified version of the G-mode algorithm, which was previously written in FORTRAN 77, in Python 2.7 and using NumPy, SciPy and Matplotlib packages. The NumPy was used for array and matrix manipulation and Matplotlib for plot control. The Scipy had a import role in speeding up G-mode, Scipy.spatial.distance.mahalanobis was chosen as distance estimator and Numpy.histogramdd was applied to find the initial seeds from which clusters are going to evolve. Scipy was also used to quickly produce dendrograms showing the distances among clusters. Finally, results for Asteroids Taxonomy and tests for different sample sizes and implementations are presented.

  17. Near Earth Asteroids- Prospection, Orbit Modification and Mining

    Science.gov (United States)

    Grandl, W.; Bazso, A.

    2014-04-01

    The number of known Near Earth Asteroids (NEAs) has increased continuously during the last decades. Now we understand the role of asteroid impacts for the evolution of life on Earth. To ensure that mankind will survive in the long run, we have to face the "asteroid threat" seriously. On one hand we will have to develop methods of detection and deflection for Hazardous Asteroids, on the other hand we can use these methods to modify their orbits and exploit their resources. Rare-earth elements, rare metals like platinum group elements, etc. may be extracted more easily from NEAs than from terrestrial soil, without environmental pollution or political and social problems. In a first step NEAs, which are expected to contain resources like nickel-iron, platinum group metals or rare-earth elements, will be prospected by robotic probes. Then a number of asteroids with a minimum bulk density of 2 g/cm^3 and a diameter of 150 to 500 m will be selected for mining. Given the long duration of an individual mission time of 10-20 years, the authors propose a "pipeline" concept. While the observation of NEAs can be done in parallel, the precursor missions of the the next phase can be launched in short intervals, giving time for technical corrections and upgrades. In this way a continuous data flow is established and there are no idle times. For our purpose Potentially Hazardous Asteroids (PHAs) seem to be a favorable choice for the following reasons: They have frequent closeencounters to Earth, their minimum orbit intersection distance is less than 0.05 AU (Astronomic Units) and they have diameters exceeding 150 meters. The necessary velocity change (delta V) for a spaceship is below 12 km/s to reach the PHA. The authors propose to modify the orbits of the chosen PHAs by orbital maneuvers from solar orbits to stable Earth orbits beyond the Moon. To change the orbits of these celestial bodies it is necessary to develop advanced propulsion systems. They must be able to deliver high

  18. Photometric Observation and Modeling Study of the Asteroid (26) Proserpina

    Science.gov (United States)

    Bin, Li; Hai-bin, Zhao; Xin, Wang

    2016-07-01

    We present the new CCD observations on the asteroid (26) Proserpina performed between 2011 December and 2012 February. Based upon the new observations, a synodic rotation period of (13.107 ± 0.002) h is obtained. Using all the light curves available sofar, the rotation vector, rotation period, and the shape model of the asteroid are determined with the convex-hull inversion method. Further more, a bootstrap method is applied to estimating the uncertainties of the rotation parameters. We derive a pair of possible rotation poles for (26) Proserpina, and believe that it has a retrograde rotation. The rotation poles are determined to be λ1 = 90.8° ± 1.4°, β1 = -53.1° ± 3.2°, and λ2 = 259.3° ± 2.2°, β2 = -62.0° ± 2.0°. The sidereal rotation periods corresponding to the two poles are almost the same as (13.109777 ± 3.8 × 10-6) h. And corresponding to this pair of rotation poles, the convex-hull shapes of the asteroid are the mirror images of each other.

  19. An anisotropic distribution of spin vectors in asteroid families

    CERN Document Server

    Hanuš, J; Ďurech, J; Warner, B D; Brinsfield, J; Durkee, R; Higgins, D; Koff, R A; Oey, J; Pilcher, F; Stephens, R; Strabla, L P; Ulisse, Q; Girelli, R

    2013-01-01

    Current amount of ~500 asteroid models derived from the disk-integrated photometry by the lightcurve inversion method allows us to study not only the spin-vector properties of the whole population of MBAs, but also of several individual collisional families. We create a data set of 152 asteroids that were identified by the HCM method as members of ten collisional families, among them are 31 newly derived unique models and 24 new models with well-constrained pole-ecliptic latitudes of the spin axes. The remaining models are adopted from the DAMIT database or the literature. We revise the preliminary family membership identification by the HCM method according to several additional criteria - taxonomic type, color, albedo, maximum Yarkovsky semi-major axis drift and the consistency with the size-frequency distribution of each family, and consequently we remove interlopers. We then present the spin-vector distributions for eight asteroidal families. We use a combined orbital- and spin-evolution model to explain ...

  20. Asteroid spin and shape modelling using two lightcurve inversion methods

    Science.gov (United States)

    Marciniak, Anna; Bartczak, Przemyslaw; Konstanciak, Izabella; Dudzinski, Grzegorz; Mueller, Thomas G.; Duffard, Rene

    2016-10-01

    We are conducting an observing campaign to counteract strong selection effects in photometric studies of asteroids. Our targets are long-period (P>12 hours) and low-amplitude (a_maxinversion methods: convex inversion (Kaasalainen et al. 2001, Icarus, 153, 37) and nonconvex SAGE modelling algorithm (Shaping Asteroids with Genetic Evolution, Bartczak et al. 2014, MNRAS, 443, 1802). These two methods are independent from each other, and are based on different assumptions for the shape.Thus, the results obtained on the same datasets provide a cross-check of both the methods and the resulting spin and shape models. The results for the spin solutions are highly consistent, and the shape models are similar, though the ones from SAGE algorithm provide more details of the surface features. Nonconvex shape produced by SAGE have been compared with direct images from spacecrafts and the first results for targets like Eros or Lutetia (Batczak et al. 2014, ACM conf. 29B) provide a high level of agreement.Another way of validation is the shape model comparison with the asteroid shape contours obtained using different techniques (like the stellar occultation timings or adaptive optics imaging) or against data in thermal infrared range gathered by ground and space-bound observatories. The thermal data could provide assignment of size and albedo, but also can help to resolve spin-pole ambiguities. In special cases, the thermal data from Spitzer and Wise/NEOWise might even help in testing specific shape features via thermal infrared lightcurves.

  1. ALMA Observations of Asteroid 3 Juno at 60 Kilometer Resolution

    CERN Document Server

    Partnership, ALMA; Kneissl, R; Moullet, A; Brogan, C L; Fomalont, E B; Vlahakis, C; Asaki, Y; Barkats, D; Dent, W R F; Hills, R; Hirota, A; Hodge, J A; Impellizzeri, C M V; Liuzzo, E; Lucas, R; Marcelino, N; Matsushita, S; Nakanishi, K; Perez, L M; Phillips, N; Richards, A M S; Toledo, I; Aladro, R; Broguiere, D; Cortes, J R; Cortes, P C; Dhawan, V; Espada, D; Galarza, F; Garcia-Appadoo, D; Guzman-Ramirez, L; Hales, A S; Humphreys, E M; Jung, T; Kameno, S; Laing, R A; Leon, S; Marconi, G; Nikolic, B; Nyman, L -A; Radiszcz, M; Remijan, A; Rodon, J A; Sawada, T; Takahashi, S; Tilanus, R P J; Vilaro, B Vila; Watson, L C; Wiklind, T; de Gregorio, I; Di Francesco, J; Mangum, J; Francke, H; Gallardo, J; Garcia, J; Gonzalez, S; Hill, T; Kaminski, T; Kurono, Y; Lopez, C; Morales, F; Plarre, K; Randall, S; van kempen, T; Videla, L; Villard, E; Andreani, P; Hibbard, J E; Tatematsu, K

    2015-01-01

    We present Atacama Large Millimeter/submillimeter Array (ALMA) 1.3 mm continuum images of the asteroid 3 Juno obtained with an angular resolution of 0.042 arcseconds (60 km at 1.97 AU). The data were obtained over a single 4.4 hr interval, which covers 60% of the 7.2 hr rotation period, approximately centered on local transit. A sequence of ten consecutive images reveals continuous changes in the asteroid's profile and apparent shape, in good agreement with the sky projection of the three-dimensional model of the Database of Asteroid Models from Inversion Techniques. We measure a geometric mean diameter of 259pm4 km, in good agreement with past estimates from a variety of techniques and wavelengths. Due to the viewing angle and inclination of the rotational pole, the southern hemisphere dominates all of the images. The median peak brightness temperature is 215pm13 K, while the median over the whole surface is 197pm15 K. With the unprecedented resolution of ALMA, we find that the brightness temperature varies ...

  2. Uncertainty maps for asteroid shape and pole solutions

    Science.gov (United States)

    Bartczak, Przemyslaw; Dudzinski, Grzegorz

    2016-10-01

    SAGE (Shaping Asteroids with Genetic Evolution) inversion method is based on genetic algorithm to obtain pole solutions, rotation periods and non-convex shapes of asteroids (Bartczak et.al, 2014). During the process computer graphics methods are used to compare model's synthetic lightcurves to photometric observations. The method is suitable for modelling both single and binary objects. A modelling run starts with a sphere, with no assumptions about the shape, and subsequently it converges to a stable spin and shape solution. Center of mas and moment of inertia are calculated for each model.Modelling of an asteroid consists of multiple runs of the process, each of them following different path towards a stable solution. As a result we obtain a family of solutions. If enough data is provided, solutions are consistent with each other and can be used for error estimation.We choose only the best models from a family of solutions, meaning every model that fits 5% threshold above best χ2 found. By comparing them we are able to construct a map of uncertainties for the shape, showing areas in good and poor agreement with chosen models. Such map can then be represented with a 3D visualisation. Moreover, we create a map of errors for pole solutions and periods.

  3. C-complex asteroids: Two main compositional families?

    Science.gov (United States)

    Vernazza, Pierre; Marsset, Michael; Beck, Pierre; Binzel, Richard; DeMeo, Francesca; Birlan, Mirel; Brunetto, Rosario; Groussin, Olivier; Marchis, Franck; Emery, Joshua P.

    2016-10-01

    An important goal of asteroid science is to link extraterrestrial materials (meteorites, IDPs) to their parent bodies in order to constrain their formation and evolution. To accomplish this task, we need to combine data from several different disciplines: ground based spectroscopic observations, laboratory studies (petrology, mineralogy), and thermal modeling. Here we report the result of a large observing campaign aimed at investigating the surface composition of the most massive C-complex Main Belt Asteroids (MBAs). We observed more than 100 of these C-types with SpeX/IRTF in the near-infrared thus complementing the existing visible part of the spectrum. We also analyzed their spectral properties in the mid-infrared, when available. We will show that by comparing the mineralogical composition of these C-type asteroids with the composition of CC meteorites and IDPs we are able to identify two main compositional families among C-types (CM-like and IDP-like). A further comparison with thermal evolution models supports the idea that these two populations likely formed in two different environments.

  4. Size Distribution of Main-Belt Asteroids with High Inclination

    CERN Document Server

    Terai, Tsuyoshi

    2010-01-01

    We investigated the size distribution of high-inclination main-belt asteroids (MBAs) to explore asteroid collisional evolution under hypervelocity collisions of around 10 km/s. We performed a wide-field survey for high-inclination sub-km MBAs using the 8.2-m Subaru Telescope with the Subaru Prime Focus Camera (Suprime-Cam). Suprime-Cam archival data were also used. A total of 616 MBA candidates were detected in an area of 9.0 deg^2 with a limiting magnitude of 24.0 mag in the SDSS r filter. Most of candidate diameters were estimated to be smaller than 1 km. We found a scarcity of sub-km MBAs with high inclination. Cumulative size distributions (CSDs) were constructed using Subaru data and published asteroid catalogs. The power-law indexes of the CSDs were 2.17 +/- 0.02 for low-inclination ( 15 deg) MBAs in the 0.7-50 km diameter range. The high-inclination MBAs had a shallower CSD. We also found that the CSD of S-like MBAs had a small slope with high inclination, whereas the slope did not vary with inclinatio...

  5. BILLIARDS: A Demonstration Mission for Hundred-Meter Class Near Earth Asteroid Disruption

    Science.gov (United States)

    Marcus, Matthew; Sloane, Joshua; Ortiz, Oliver; Barbee, Brent W.

    2015-01-01

    Currently, no planetary defense demonstration mission has ever been flown. While Nuclear Explosive Devices (NEDs) have significantly more energy than a kinetic impactor launched directly from Earth, they present safety and political complications, and therefore may only be used when absolutely necessary. The Baseline Instrumented Lithology Lander, Inspector, and Asteroid Redirection Demonstration System (BILLIARDS) is a demonstration mission for planetary defense, which is capable of delivering comparable energy to the lower range of NED capabilities in the form of a safer kinetic impactor. A small asteroid (disrupt the larger asteroid. To reduce the cost and complexity, an asteroid pair which has a natural close approach is selected.

  6. The problem of the near-earth asteroids encountering the earth

    Institute of Scientific and Technical Information of China (English)

    季江徽[1; 刘林[2

    2000-01-01

    The asteroids are the most important small bodies in the solar system, while the movement of the near-earth-asteroids (NEAs) is specially concerned by the world. The focus on these asteroids is that they encounter the earth. The orbital evolution of this kind of asteroid is studied by analyzing and comparing them; reasonable dynamical models and corresponding algorithm are given, and the formal numbered NEAs are calculated. The results of the minimal distance and the very close-approach time with the earth agree well with those announced by the Minor Planet Center (MFC).

  7. The problem of the near-earth asteroids encountering the earth

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The asteroids are the most important small bodies in the solar system, while the movement of the near-earth-asteroids (NEAs) is specially concerned by the world. The focus on these asteroids is that they encounter the earth. The orbital evolution of this kind of asteroid is studied by analyzing and comparing them; reasonable dynamical models and corresponding algorithm are given, and the formal numbered NEAs are calculated. The results of the minimal distance and the very close-approach time with the earth agree well with those announced by the Minor Planet Center (MPC).

  8. Towing Asteroids with Gravity Tractors Enhanced by Tethers and Solar Sails

    Science.gov (United States)

    Shen, Haijun; Roithmayr, Carlos M.

    2015-01-01

    Material collected from an asteroid's surface can be used to increase gravitational attraction between the asteroid and a Gravity Tractor (GT); the spacecraft therefore operates more effectively and is referred to as an Enhanced Gravity Tractor (EGT). The use of tethers and solar sails to further improve effectiveness and simplify operations is investigated. By employing a tether, the asteroidal material can be placed close to the asteroid while the spacecraft is stationed farther away, resulting in a better safety margin and improved thruster efficiency. A solar sail on a spacecraft can naturally provide radial offset and inter-spacecraft separation required for multiple EGTs.

  9. The Orbital Evolution of 2007 VA85, an Amor-type Asteroid on a Retrograde Orbit.

    Science.gov (United States)

    Kankiewicz, P.; Włodarczyk, I.

    2010-06-01

    Among the known population of asteroids on retrograde orbits (i > 90°) we found an object classified as an Amor-type asteroid. During the analysis of the first results of astrometry, we found some possible Earth-impact solutions for this asteroid. After taking into account the latest observations, we excluded any significant impact solution. However, this asteroid is the first known example of potentially hazardous object on a retrograde orbit. We also investigated the orbital evolution of 2007 VA85 (1 My in the past), obtaining possible scenarios of its dynamical origin.

  10. Rotational and translational considerations in kinetic impact deflection of potentially hazardous asteroids

    Science.gov (United States)

    Zhang, Fei; Xu, Bo; Circi, Christian; Zhang, Lei

    2017-04-01

    Kinetic impact may be the most reliable and easily implemented method to deflect hazardous asteroids using current technology. Depending on warning time, it can be effective on asteroids with diameters of a few hundred meters. Current impact deflection research often focuses on the orbital dynamics of asteroids. In this paper, we use the ejection outcome of a general oblique impact to calculate how an asteroid's rotational and translational state changes after impact. The results demonstrate how small impactors affect the dynamical state of small asteroids having a diameter of about 100 m. According to these consequences, we propose using several small impactors to hit an asteroid continuously and gently, making the deflection mission relatively flexible. After calculating the rotational variation, we find that the rotational state, especially of slender non-porous asteroids, can be changed significantly. This gives the possibility of using multiple small impactors to mitigate a potentially hazardous asteroid by spinning it up into pieces, or to despin one for future in-situ investigation (e.g., asteroid retrieval or mining).

  11. Comets, Asteroids and Rubble Piles: not just debris

    Science.gov (United States)

    Harold, J. B.; Dusenbery, P.

    2010-12-01

    The National Center for Interactive Learning at the Space Science Institute (NCIL @ SSI) is developing a variety of asteroids related education activities as part of several E/PO projects, including Finding NEO (funded through NSF and NASA SMD); Great Balls of Fire! (funded through NSF); and a partnership with the WISE (Wide-field Infrared Survey Explorer) mission. These activities range from a web site to traveling exhibits in three different sizes. The Killer Asteroids web site (www.killerasteroids.org) includes background information on comets and asteroids as well as a number of interactive activities and games. These include a game that compares the risk of death from an asteroid impact to other hazards; a game and video vignettes on the role of backyard astronomers in light curve research; a physics-based asteroid deflection game; and a Google Earth -based "drop a rock on your house" activity. In addition, the project is developing a small, portable exhibit suitable for use in libraries or visitors centers. Great Balls of Fire! includes two separate traveling exhibitions: a 3000 square foot exhibition for science centers, and a 500 square foot version for smaller venues. Both will begin national tours in the summer of 2011. The Great Balls of Fire! exhibit program includes a free Education Program for docents and educators, and an Outreach Program to amateur astronomers around the country through the Astronomical Society of the Pacific’s (ASP) Astronomy from the Ground Up program. The project will facilitate partnerships between host venues and local astronomy clubs that can interact with the public using a toolkit of activities developed by ASP. Great Balls of Fire! Represents a collaboration between scientists, educators, exhibit designers, graphic artists, evaluators, education researchers, and three teams of middle school students who acted as advisors. The project’s exhibit design firm is Jeff Kennedy Associates Inc. We will present a summary of the

  12. LSST's Projected Near-Earth Asteroid Discovery Performance

    Science.gov (United States)

    Chesley, Steven R.; Veres, Peter

    2016-10-01

    The Large Synoptic Survey Telescope (LSST) is an ambitious project that has the potential to make major advances in Near-Earth Asteroid search efforts. With construction already underway and major optical elements complete, first light is set for 2020, followed by two years of commissioning. Once regular survey operations begin in 2022, LSST will systematically survey the observable sky over a ten-year period from its site on Cerro Pachon, Chile. With an 8.4 m aperture (6.5 m effective), 9.6 square degree field of view, and a 3.2-Gigapixel camera, LSST represents the most capable asteroid survey instrument ever built. LSST will be able cover over 6000 square degrees of sky per clear night with single visit exposures of 30 s, reaching a faint limit of 24.5 mag in the r band. However the cadence of survey operations is a critical factor for the near-Earth asteroid search performance, and there are multiple science drivers with different cadence objectives that are competing to shape the final survey strategy. We examine the NEA search performance of various LSST search strategies, paying particular attention to the challenges of linking large numbers asteroid detections in the presence of noise. Our approach is to derive lists of synthetic detections for a given instantiation of the LSST survey, based on an assumed model for the populations of solar system objects from the main asteroid belt inwards to the near-Earth population. These detection lists are combined with false detection lists that model both random noise and non-random artifacts resulting from image differencing algorithms. These large detection lists are fed to the Moving Object Processing System (MOPS), which attempts to link the synthetic detections correctly without becoming confused or overwhelmed by the false detections. The LSST baseline survey cadence relies primarily on single night pairs of detections, with roughly 30-60 min separating elements of the pair. The strategy of using pairs is an

  13. Yarkovsky V-shape identification of asteroid families

    Science.gov (United States)

    Bolin, Bryce T.; Delbo, Marco; Morbidelli, Alessandro; Walsh, Kevin J.

    2017-01-01

    There are only a few known main belt (MB) asteroid families with ages greater than 2 Gyr (Brož et al., 2013; Spoto et al., 2015). Estimates based on the family producing collision rate suggest that the lack of > 2 Gyr-old families may be due to a selection bias in current techniques used to identify families. Family fragments disperse in their orbital elements, semi-major axis, a, eccentricity, e, and inclination, i, due to secular resonances, close encounters with massive asteroids and the non-gravitational Yarkovsky force. This causes the family fragments to be indistinguishable from the background of the main belt making them more difficult to identify with the hierarchical clustering method (HCM) with increasing family age. The discovery of the Eulalia and new Polana families in the inner belt relied on new techniques because Yarkovsky spreading made them too disperse to be identified using the classical HCM. The techniques used to discover the new Polana and Eulalia families are modified here to identify asteroid families by searching for correlations between a and asteroid diameter, D, or absolute magnitude, H. A group of asteroids is identified as a collisional family if its boundary in the a vs. 1/D or a vs. H planes has a characteristic V-shape which is due to the size dependent Yarkovsky spreading. The V-shape boundary is identified with two separate techniques. The first technique identifies a border by measuring a steep drop between the number of objects inside and outside of the border. The second technique identifies the V-shape border by measuring a peak in the number density of objects in a vs. 1/D , H space. Families are identified with just one or both V-shape identifying techniques. The V-shape techniques are demonstrated on the known families of Erigone, Vesta, Koronis, and families difficult to identify by HCM such as Flora, Baptistina, new Polana, Eulalia and Karin. Future applications of the technique, such as in a large scale search for > 2

  14. Jupiter Magnetospheric Orbiter and Trojan Asteroid Explorer in EJSM

    Science.gov (United States)

    Sasaki, Sho; Fujimoto, Masaki; Yano, Hajime; Takashima, Takeshi; Kasaba, Yasumasa; Funase, Ryu; Tsuda, Yuichi; Kawaguchi, Junichiro; Kawakatsu, Yasuhiro; Mori, Osamu; Morimoto, Mutsuko; Yoshida, Fumi; Takato, Naruhisa

    The international mission to explore the Jovian system is planned as Europa Jupiter System Mission (EJSM) aiming at the launch in 2020. EJSM consists of (1) the Jupiter Europa Orbiter (JEO) by NASA, (2) the Jupiter Ganymede Orbiter (JGO) by ESA, and (3) the Jupiter Magnetospheric Orbiter (JMO) studied by JAXA (Japan Aerospace Exploration Agency). In February 2009, NASA and ESA decided to continue the study of EJSM as a candidate of the outer solar system mission. In JAXA, a mission plan combining Trojan asteroid explorer with JMO started. According to the mission plan, as the main spacecraft flies by Jupiter, it will deploy the JMO satellite around Jupiter. Then the main will target one (or two) Trojan asteroids. JMO is a spin-stabilized satellite which will have magnetometers, low-energy plasma spectrome-ters, medium energy particle detectors, energetic particle detectors, electric field / plasma wave instruments, an ENA imager, an EUV spectrometer, and a dust detector. Collaborating with plasma instruments on board JEO and JGO, JMO will investigate the fast-rotating huge mag-netosphere to clarify the energy procurement from the rotation of Jupiter to the magnetosphere and to clarify the interaction between the solar wind and the magnetosphere. JAXA started the study of a solar power sail for deep space explorations. In addition to the function of a solar sail (photon propulsion), the solar power sail system has very efficient ion engines where electric power is produced solar panels within the sail. Currently we are studying a mission to Jupiter and Trojan asteroids using a large (100m-scale) solar power sail that can transfer large payload as far as Jupiter. Trojan asteroids, which orbit around Jupiter's Lagrangian points, are primitive bodies with information of the early solar system as well as raw solid materials of Jovian system. Proposed instruments for the Trojan spacecraft are cameras, IR spectrometers, XRS, a laser altimeter, and a small surface rover

  15. Analytical model of impact disruption of satellites and asteroids

    Science.gov (United States)

    Leliwa-Kopystyński, J.; Włodarczyk, I.; Burchell, M. J.

    2016-04-01

    A model of impact disruption of the bodies with sizes from the laboratory scale to that of an order of 100 km is developed. On the lowermost end of the target size the model is based on the numerous laboratory data related to the mass-velocity distribution of the impact produced fragments. On the minor-planets scale the model is supported by the data related to the largest observed craters on small icy satellites and on some asteroids (Leliwa-Kopystynski, J., Burchell, M.J., Lowen, D. [2008]. Icarus 195, 817-826). The model takes into account the target disruption and the dispersion of the impact produced fragments against the intermolecular forces acting on the surfaces of the contacts of the fragments and against self-gravitation of the target. The head-on collisions of non-rotating and non-porous targets and impactors are considered. The impactor delivers kinetic energy but its mass is neglected in comparison to mass of the target. For this simple case the analytical formulae for specific disruption energy as well as for specific energy of formation of the largest craters are found. They depend on a set of parameters. Of these the most important (i.e. with the greatest influence on the final result) are three rather weakly known parameters. They are: (i) The exponent γ in the distribution function of the fragments. (ii) The characteristic velocity v0 that appears in the velocity distribution of the ejected fragments. (iii) The exponent β in the mass-velocity distribution. The influence of the choice of the numerical values of these parameters on the final results has been studied. Another group of parameters contains the relevant material data. They are: (a) The energy σ of breaking of the intermolecular bonds of the target material per unit of the fragment surface and (b) the density ρ of the target. According to our calculations the transition between the strength regime and the gravitational regime is in the range of the target radius from ∼0.4 km to

  16. COMPOSITION OF POTENTIALLY HAZARDOUS ASTEROID (214869) 2007 PA8: AN H CHONDRITE FROM THE OUTER ASTEROID BELT

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez, Juan A.; Reddy, Vishnu; Corre, Lucille Le [Planetary Science Institute, Tucson, AZ 85719 (United States); Dykhuis, Melissa [Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85719 (United States); Lindsay, Sean, E-mail: jsanchez@psi.edu [Atmospheric, Oceanic, and Planetary Physics, University of Oxford (United Kingdom)

    2015-07-20

    Potentially hazardous asteroids (PHAs) represent a unique opportunity for physical characterization during their close approaches to Earth. The proximity of these asteroids makes them accessible for sample-return and manned missions, but could also represent a risk for life on Earth in the event of collision. Therefore, a detailed mineralogical analysis is a key component in planning future exploration missions and developing appropriate mitigation strategies. In this study we present near-infrared spectra (∼0.7–2.55 μm) of PHA (214869) 2007 PA8 obtained with the NASA Infrared Telescope Facility during its close approach to Earth on 2012 November. The mineralogical analysis of this asteroid revealed a surface composition consistent with H ordinary chondrites. In particular, we found that the olivine and pyroxene chemistries of 2007 PA8 are Fa{sub 18}(Fo{sub 82}) and Fs{sub 16}, respectively. The olivine–pyroxene abundance ratio was estimated to be 47%. This low olivine abundance and the measured band parameters, close to the H4 and H5 chondrites, suggest that the parent body of 2007 PA8 experienced thermal metamorphism before being catastrophically disrupted. Based on the compositional affinity, proximity to the J5:2 resonance, and estimated flux of resonant objects we determined that the Koronis family is the most likely source region for 2007 PA8.

  17. Composition of Potentially Hazardous Asteroid (214869) 2007 PA8: An H Chondrite from the Outer Asteroid Belt

    CERN Document Server

    Sanchez, Juan A; Dykhuis, Melissa; Lindsay, Sean; Corre, Lucille Le

    2015-01-01

    Potentially hazardous asteroids (PHAs) represent a unique opportunity for physical characterization during their close approaches to Earth. The proximity of these asteroids makes them accessible for sample-return and manned missions, but could also represent a risk for life on Earth in the event of collision. Therefore, a detailed mineralogical analysis is a key component in planning future exploration missions and developing appropriate mitigation strategies. In this study we present near-infrared spectra (0.7-2.55 microns) of PHA (214869) 2007 PA8 obtained with the NASA Infrared Telescope Facility during its close approach to Earth on November 2012. The mineralogical analysis of this asteroid revealed a surface composition consistent with H ordinary chondrites. In particular, we found that the olivine and pyroxene chemistries of 2007 PA8 are Fa18(Fo82) and Fs16, respectively. The olivine-pyroxene abundance ratio was estimated to be 47%. This low olivine abundance and the measured band parameters, close to t...

  18. The Physical Characterization of the Potentially-Hazardous Asteroid 2004 BL86: A Fragment of a Differentiated Asteroid

    CERN Document Server

    Reddy, Vishnu; Sanchez, Juan A; Takir, Driss; Thomas, Cristina A; Hardersen, Paul S; Ogmen, Yenal; Benni, Paul; Kaye, Thomas G; Gregorio, Joao; Garlitz, Joe; Polishook, David; Corre, Lucille Le; Nathues, Andreas

    2015-01-01

    The physical characterization of potentially hazardous asteroids (PHAs) is important for impact hazard assessment and evaluating mitigation options. Close flybys of PHAs provide an opportunity to study their surface photometric and spectral properties that enable identification of their source regions in the main asteroid belt. We observed PHA (357439) 2004 BL86 during a close flyby of the Earth at a distance of 1.2 million km (0.0080 AU) on January 26, 2015, with an array of ground-based telescopes to constrain its photometric and spectral properties. Lightcurve observations showed that the asteroid was a binary and subsequent radar observations confirmed the binary nature and gave a primary diameter of 300 meters and a secondary diameter of 50-100 meters. Our photometric observations were used to derive the phase curve of 2004 BL86 in the V-band. Two different photometric functions were fitted to this phase curve, the IAU H-G model (Bowell et al. 1989) and the Shevchenko model (Shevchenko 1996). From the fi...

  19. Using asteroid families to test planetesimal differentiation hypotheses

    Science.gov (United States)

    Jacobson, S.; Campins, H.; Delbo', M.; Michel, P.; Tanga, P.; Hanuš, J.; Morbidelli, A.

    2014-07-01

    There have been a series of papers (e.g., Weiss et al. 2008, 2010, 2012; Carporzen et al. 2011; Elkins-Tanton et al. 2011) suggesting that large planetesimals should have metamorphic grading within their crusts and possibly fully-differentiated interiors with mantles and cores. This is a very attractive hypothesis consistent with ideas that planetesimals form as large bodies (Johansen et al. 2007, Cuzzi et al. 2008, Morbidelli et al. 2009) and form early in Solar System history when radioactive heating is still important. It is natural to look to the asteroid belt, our prime reservoir of terrestrial planet building blocks (i.e., left-over planetesimals), for confirmation of this idea. Asteroid families, long known to be the debris from catastrophic disruptions (Hirayama 1918, Michel et al. 2003) conveniently expose the interiors of these left-overs. From simulations of the catastrophic disruption process, we know that not all material is ejected equally. Material near the surface is given higher expulsion velocities and divided into smaller pieces (Michel et al. 2004). Furthermore, while catastrophic disruptions appear to be a messy process, the largest remnants, including those formed by re-accumulation of smaller fragments, come from coherent sections of the progenitor body, although the extent and depth of these sections within the progenitor depend on its internal structure (Michel et al. 2014). This suggests that the ejected material should also maintain a coherent compositional structure (Michel et al., 2004). Therefore, compositional gradients within planetesimals should expose themselves within asteroid families. While all asteroid families share a number of common features, there is a large diversity of membership numbers, progenitor masses, collision energy, formation times, and spectroscopic type and sub-type both between and within families (Zappala et al. 1995, Nesvorny 2012). This compositional diversity allows for a thorough exploration of the

  20. Physical studies of asteroids at the Yunnan Observatories

    Science.gov (United States)

    Wang, X.; Muinonen, K.

    2014-07-01

    The Yunnan observatories are among the major astronomical observatories in China. There are three sites for the Yunnan observatories: Kunming, Lijiang, and Fuxian lake. There is a 1.0-m telescope at the Kunming site and a 2.4-m telescope at the Lijiang site; these are usually used for asteroid studies and are thus discussed here. Asteroids are thought to be remnants of planetesimals in the Solar System. Their physical properties, such as their spins and shapes, can provide important constraints on the formation and evolution of the entire Solar System as well as the individual small bodies themselves. Because the two telescopes are located at low latitudes (of about 25 degrees), they are useful for the observation of small Solar System bodies. With the photometric data obtained by the two telescopes, we have carried out studies on the determination of physical parameters for selected asteroids, e.g., the spin parameters and the convex shape. We analyze the surface characteristics of asteroids with the help of the spectral data from the 2.4-m telescope. For the determination of the spin parameters and the convex shape, several inversion methods have been developed [1,2; also, Muinonen et al., present meeting], e.g., the convex inversion method [3,4]. Under the frame of a collaboration between the Yunnan Observatories and the University of Helsinki, we carried out studies on lightcurve inversion. Here, with the virtual-photometry Monte Carlo method (cf., [5]), we investigate the relationship between the uncertainties of the solutions of the convex inversion and the photometric data for some selected asteroids with different orbital inclinations. For the spin parameters and parameters related to the scattering law of the surface, uncertainties are estimated from the distributions of the parameter values derived from the virtual photometric data. As for the modeled shape, the corresponding virtual shapes are compared with a best-fit shape. The reliability of the