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 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.

  4. 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

  5. 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.

  6. Asteroid rotation rates

    Science.gov (United States)

    Dermott, S. F.; Harris, A. W.; Murray, C. D.

    1984-01-01

    A trend of increasing mean rotational frequency with increasing diameter is noted in asteroids with diameters greater than 120 km, irrespective of M-, S-, and C-type asteroid subset and family or nonfamily membership. This trend cannot be accounted for by observational selection. For asteroids with diameters smaller than 120 km mean rotational frequency increases with decreasing diameter, but within this group there is a subset with exceptionally long rotational periods. This marked change in the distribution at 120-km diameter could separate primordial asteroids from their collision products. It is also noted that, for asteroids of a given diameter, M asteroids rotate faster than S asteroids, which in turn rotate faster than C asteroids. For all types, family members rotate faster than nonfamily members.

  7. 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...

  8. The Active Asteroids

    CERN Document Server

    Jewitt, David; Agarwal, Jessica

    2015-01-01

    Some asteroids eject dust, producing transient, comet-like comae and tails; these are the active asteroids. The causes of activity in this newly-identified population are many and varied. They include impact ejection and disruption, rotational instabilities, electrostatic repulsion, radiation pressure sweeping, dehydration stresses and thermal fracture, in addition to the sublimation of asteroidal ice. These processes were either unsuspected or thought to lie beyond the realm of observation before the discovery of asteroid activity. Scientific interest in the active asteroids lies in their promise to open new avenues into the direct study of asteroid destruction, the production of interplanetary debris, the abundance of asteroid ice and the origin of terrestrial planet volatiles.

  9. The asteroid ring

    Science.gov (United States)

    Dermott, S. F.; Murray, C. D.

    1982-01-01

    From a statistical analysis of asteroid orbital period data, it is shown that the present distribution of asteroids is strongly correlated with the present orbital period of Jupiter (to 1 part in 5000). By analyzing the distribution of orbital eccentricities and inclinations it is shown that the resonant structure of the belt was formed after the asteroids dispersed from the near-coplanar disk in which they accreted.

  10. An overview of the asteroids

    Science.gov (United States)

    Binzel, Richard P.

    1989-01-01

    An introductory overview of the field of asteroid science is presented, with emphasis placed on the accomplishments of the 1980s. Following the survey of known asteroids, attention is given to the observations of asteroids with the IRAS. Particular consideration is given to the origin and evolution of asteroids and their interrelations. Possible future directions of asteroid research are discussed together with the potential of the Hubble Space Telescope for providing new data on asteroid surface chemistry, geology, structure, and morphology.

  11. Modeling of Asteroid Shapes

    CERN Document Server

    Kokorev, Andrii

    2016-01-01

    In this article we consider different methods of modeling asteroid shapes, especially lightcurve inversion technique, and scattering laws used for it. We also introduce our program, which constructs lightcurves for a given asteroid shape model. It can be used to comparing shape model with observational data.

  12. Global Asteroid Risk Analysis

    CERN Document Server

    Rumpf, Clemens

    2014-01-01

    Potentially impacting asteroids were analysed for their impact risk on the Earth. To this end, the Asteroid Risk Mitigation Optimization and Research (ARMOR) tool is currently being developed. The tool's modules are described and their validation is documented. Based on the asteroid ephemeris, the tool calculates the impact location probability distribution on the surface of the Earth (in the literature, occasionally referred to as risk corridor). NASA's Near Earth Object (NEO) risk list served as the source for asteroid ephemerides. The Line of Variation (LOV) method was employed to find virtual impactors. While offering a simple and fast way of identifying virtual impactors, the method provides a low impactor identification rate. This is because the search space is tightly constricted to the LOV and thus excludes virtual impactors located elsewhere in the asteroid position uncertainty region. The method's performance was evaluated and suggestions for improvements are provided. Application of the tool showed...

  13. Polarimetric properties of asteroids

    Science.gov (United States)

    Shestopalov, D. I.; Golubeva, L. F.

    2015-11-01

    Quite frequently astronomic polarimetric observations of different celestial bodies do not guarantee a proper phase angle coverage that is required for estimating all of the attributes of their polarization phase curves with a high accuracy. To approximate the phase dependences of polarization observed for particulate surfaces, we use a simple empiric formula recently suggested by Shestopalov (2004). The efficiency of the approximating function in a wide range of phase angles is illustrated with the use of the results of polarimetric measurements of lunar areas, lunar samples, and near-Earth asteroids. For asteroids of various types, we can reproduce their negative polarization branches with adequate accuracy and roughly estimate a probable value of the maximum polarization degree at an appropriate phase angle. From the polarimetric database available at NASA PDS [Asteroid Polarimetric Database V7.0 (2012)] we calculated the main parameters of 153 polarimetric curves of asteroids in various spectral bands with the accuracy comparable to the observation errors. One more purpose of our analysis was to find correlations between the polarimetric and photometric properties of asteroids. For C-, M-, S-, E-type asteroids, the characteristics of the negative branch of polarization curves turned out to correlate closely with the phase coefficient of the photometric function of asteroids and the photometric roughness of asteroid surfaces. This implies that the complex geometry of the surface microrelief affects the polarization properties of asteroids. In particular, the data scattering around regression lines on the plots of the albedo versus the depth of negative polarization branch and the slope of the polarimetric function at inversion angle strongly depends on the differences in the photometric roughness of asteroid surfaces.

  14. 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...

  15. 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...

  16. 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

  17. Threat Mitigation: The Asteroid Tugboat

    OpenAIRE

    Schweickart, Russell; Chapman, Clark; Durda, Dan; Hut, Piet

    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 ...

  18. 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.

  19. 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

  20. 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....

  1. 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.

  2. Asteroid Lightcurve Photometry

    Science.gov (United States)

    Harris, A. W.

    2004-05-01

    With the advent of modestly priced CCD cameras and computer controller and reduction software, amateurs can now do photometry on fainter targets than was possible even from large observatories only a decade or so ago. This has led to an explosion of lightcurve data that in turn has yielded rich results. We now have rotation periods for more than 1500 asteroids, extending down to objects only tens of meters in diameter, and well determined shapes and pole orientations of more than 100 objects. Among smaller asteroids, the dispersion in rotation rates ranges from minutes to months, with the slower ones mostly "tumbling," or in states of non-principal axis rotation. The fastest ones must be monolithic, as centrifugal force exceeds their gravity. But among those larger than a few hundred meters diameter, there is a "rotation barrier" at the rate where gravity and centrifugal force match, suggesting that most asteroids this large or larger are "rubble piles." The broad dispersion in spin rates, almost a bimodal distribution, has long been a mystery, but now appears likely to be due to thermal radiation torques from the randomly asymmetric shapes of small asteroids. This is a major paradigm shift from the past, where mutual collisions were considered to be the dominant (or only) evolutionary process affecting spins. Amateur observations have already contributed a great deal leading to this new view, and much remains to be done, providing abundant opportunities for amateur-professional collaborations.

  3. Multiple origins of asteroid pairs

    Science.gov (United States)

    Jacobson, Seth A.

    2016-01-01

    Rotationally fissioned asteroids produce unbound asteroid pairs 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 higher mass ratios or faster rotating primaries. However, the process of 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.

  4. 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.

  5. 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.

  6. 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...

  7. 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...

  8. 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.

  9. 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

  10. Evolutionary Pathways for Asteroid Satellites

    Science.gov (United States)

    Jacobson, Seth Andrew

    2015-08-01

    The YORP-induced rotational fission hypothesis is a proposed mechanism for the creation of small asteroid binaries, which make up approximately 1/6-th of the near-Earth asteroid and small Main Belt asteroid populations. The YORP effect is a radiative torque that rotationally accelerates asteroids on timescales of thousands to millions of years. As asteroids rotationally accelerate, centrifugal accelerations on material within the body can match gravitational accelerations holding that material in place. When this occurs, that material goes into orbit. Once in orbit that material coalesces into a companion that undergoes continued dynamical evolution.Observations with radar, photometric and direct imaging techniques reveal a diverse array of small asteroid satellites. These systems can be sorted into a number of morphologies according to size, multiplicity of members, dynamical orbit and spin states, and member shapes. For instance, singly synchronous binaries have short separation distances between the two members, rapidly rotating oblate primary members, and tidally locked prolate secondary members. Other confirmed binary morphologies include doubly synchronous, tight asynchronous and wide asynchronous binaries. Related to these binary morphologies are unbound paired asteroid systems and bi-lobate contact binaries.A critical test for the YORP-induced rotational fission hypothesis is whether the binary asteroids produced evolve to the observed binary and related systems. In this talk I will review how this evolution is believed to occur according to gravitational dynamics, mutual body tides and the binary YORP effect.

  11. Photometry of Karin family asteroids

    NARCIS (Netherlands)

    Hahn, G.; Mottola, S.; Sen, A. K.; Harris, A. W.; Kührt, E.; Mueller, M.

    2006-01-01

    We have performed photometric observations in the V-band of two asteroids belonging to the Karin asteroid family, (11728) Einer and (93690) 2000 VE21 , using the 2-m Himalayan Chandra Telescope, Hanle and 2k ×4k pixels CCD imager. We obtained measurements during two nights (November 25 and 26, 2005)

  12. 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...

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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

  18. 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

  19. Asteroid airburst altitude vs. strength

    Science.gov (United States)

    Robertson, Darrel; Wheeler, Lorien; Mathias, Donovan

    2016-10-01

    Small NEO asteroids (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.

  20. 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.

  1. 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

  2. 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...

  3. Asteroid Exploration and Exploitation

    Science.gov (United States)

    Lewis, John S.

    2006-01-01

    John S. Lewis is Professor of Planetary Sciences and Co-Director of the Space Engineering Research Center at the University of Arizona. He was previously a Professor of Planetary Sciences at MIT and Visiting Professor at the California Institute of Technology. Most recently, he was a Visiting Professor at Tsinghua University in Beijing for the 2005-2006 academic year. His research interests are related to the application of chemistry to astronomical problems, including the origin of the Solar System, the evolution of planetary atmospheres, the origin of organic matter in planetary environments, the chemical structure and history of icy satellites, the hazards of comet and asteroid bombardment of Earth, and the extraction, processing, and use of the energy and material resources of nearby space. He has served as member or Chairman of a wide variety of NASA and NAS advisory committees and review panels. He has written 17 books, including undergraduate and graduate level texts and popular science books, and has authored over 150 scientific publications.

  4. Asteroid secular dynamics: Ceres' fingerprint identified

    OpenAIRE

    Novaković, Bojan; Maurel, Clara; 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 b...

  5. Asteroid Systems: Binaries, Triples, and Pairs

    CERN Document Server

    Margot, Jean-Luc; Taylor, Patrick; Carry, Benoît; Jacobson, Seth

    2015-01-01

    In the past decade, the number of known binary near-Earth asteroids has more than quadrupled and the number of known large main belt asteroids with satellites has doubled. Half a dozen triple asteroids have been discovered, and the previously unrecognized populations of asteroid pairs and small main belt binaries have been identified. The current observational evidence confirms that small (20 km) binaries with small satellites are most likely created during large collisions.

  6. Reflectance spectroscopy and asteroid surface mineralogy

    Science.gov (United States)

    Gaffey, Michael J.; Bell, Jeffrey F.; Cruikshank, Dale P.

    1989-01-01

    Information available from reflectance spectroscopy on the surface mineralogy of asteroids is discussed. Current spectral interpretive procedures used in the investigations of asteroid mineralogy are described. Present understanding of the nature and history of asteroids is discussed together with some still unresolved issues such as the source of ordinary chondrites.

  7. 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.

  8. 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

  9. 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 ...

  10. 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.

  11. Resonant Structure of the THEMIS Asteroid Family

    Science.gov (United States)

    Kehoe, T. J. J.; Murray, C. D.

    1996-09-01

    The existence of resonant structure associated with low-order Jovian mean-motion commensurabilities within the main asteroid belt is already well established. However, previous studies have also suggested evidence for gaps within individual asteroid families. Whereas the Kirkwood gaps in the main asteroid belt are known to result from the actual removal of asteroids from resonant locations, it is not clear if this is also the case for the gaps evident within asteroid families. Indeed, the fact that asteroid families are identified by clustering in proper element space prompted Dermott & Murray (1981) to suggest that some of these gaps might only result from a failure to identify asteroids undergoing resonant perturbations as family members. We have investigated this hypothesis for the particular case of the Themis family of asteroids by numerically integrating the orbits of a carefully created artificial asteroid family. The orbital elements for this artificial family were constructed with proper element distributions closely resembling those of the actual Themis family but with any resonant structure removed. These orbits were then evolved to determine whether asteroids were indeed being removed from resonant locations and to monitor the mechanisms by which this occurred. We present evidence which indicates that the 2:1 Jovian mean-motion resonance may have played an important role in depleting the original Themis asteroid family of some of its members.

  12. NASA's Asteroid Redirect Mission (ARM)

    Science.gov (United States)

    Abell, Paul; Mazanek, Dan; Reeves, David; Naasz, Bo; Cichy, Benjamin

    2015-11-01

    The National Aeronautics and Space Administration (NASA) is developing a robotic mission to visit a large near-Earth asteroid (NEA), collect a multi-ton boulder from its surface, and redirect it into 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. 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. In order to maximize the knowledge return from the mission, NASA is organizing an ARM Investigation Team, which is being preceded by the Formulation Assessment and Support Team. These teams will be comprised of scientists, technologists, and other qualified and interested individuals to help plan the implementation and execution of ARM. An overview of robotic and crewed segments of ARM, including the mission requirements, NEA targets, and mission operations, will be provided along with a discussion of the potential opportunities associated with the mission.

  13. Lightcurve Analysis of Fourteen Asteroids

    Science.gov (United States)

    Pray, Donald P.; Galad, Adrian; Husarik, Marek; Oey, Julian

    2008-03-01

    Lightcurve period and amplitude are reported for the following asteroids observed at Carbuncle Hill Observatory and other sites between December 2006 and March 2007: 1806 Derice, 2472 Bradman, 2480 Popanov, 2768 Gorky, 2874 Jim Young, 3314 Beals, 4936 Butakov, 5676 Voltaire, 6709 Hiromiyuki, 6737 Okabayashi, 9368 Eshashi, 13497 Ronstone, (14142) 1998 SG10 and (46598) 1993 FT2.

  14. 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

  15. 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.

  16. Near Earth Asteroid Characteristics for Asteroid Threat Assessment

    Science.gov (United States)

    Dotson, J.; Wooden, D. H.; Bryson, K.; Ostrowski, D. R.

    2015-12-01

    Information about the physical characteristics of Near Earth Asteroids (NEAs) is needed to model behavior during atmospheric entry, to assess the risk of an impact, and to model possible mitigation techniques. The intrinsic properties of interest to entry and mitigation modelers, however, rarely are directly measureable. Instead we measure other properties and infer the intrinsic physical properties, so determining the complete set of characteristics of interest is far from straightforward. In addition, for the majority of NEAs, only the basic measurements exist so often properties must be inferred from statistics of the population of more completely characterized objects. We will provide an assessment of the current state of knowledge about the physical characteristics of importance to asteroid threat assessment. In addition, an ongoing effort to collate NEA characteristics into a readily accessible database for use by the planetary defense community will be discussed.

  17. Designing Asteroid Impact Scenario Trajectories

    Science.gov (United States)

    Chodas, Paul

    2016-05-01

    In order to study some of the technical and geopolitical issues of dealing with an asteroid on impact trajectory, a number of hypothetical impact scenarios have been presented over the last ten years or so. These have been used, for example, at several of the Planetary Defense Conferences (PDCs), as well as in tabletop exercises with the Federal Emergency Management Agency (FEMA), along with other government agencies. The exercise at the 2015 PDC involved most of the attendees, consisted of seven distinct steps (“injects”), and with all the presentations and discussions, took up nearly 10 hours of conference time. The trajectory for the PDC15 scenario was entirely realistic, and was posted ahead of the meeting. It was made available in the NEO Program’s Horizons ephemeris service so that users could , for example, design their own deflection missions. The simulated asteroid and trajectory had to meet numerous very exacting requirements: becoming observable on the very first day of the conference, yet remaining very difficult to observe for the following 7 years, and far enough away from Earth that it was out of reach of radar until just before impact. It had to be undetectable in the past, and yet provide multiple perihelion opportunities for deflection in the future. It had to impact in a very specific region of the Earth, a specific number of years after discovery. When observations of the asteroid are simulated to generate an uncertainty region, that entire region must impact the Earth along an axis that cuts across specific regions of the Earth, the “risk corridor”. This is important because asteroid deflections generally move an asteroid impact point along this corridor. One scenario had a requirement that the asteroid pass through a keyhole several years before impact. The PDC15 scenario had an additional constraint that multiple simulated kinetic impactor missions altered the trajectory at a deflection point midway between discovery and impact

  18. 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

  19. Migration of Near Earth Asteroid to Jovian-Crosser Asteroid:Case Study 3552 Don Quixote

    OpenAIRE

    Siregar, Suryadi

    2010-01-01

    It is generally recognized that main-belt asteroids (MBAs) and nuclei of extinct comets are the two main sources for the Near-Earth-Asteroids (NEAs). Theoretical studies of NEAs dynamics and numerical modelling of their orbital motions showed that the resonance mechanism for supplying NEAs is quite sufficient to sustain this population. Asteroid 1983 SA, also known as 3552 Don Quixote, is one of Near Earth Asteroids (NEAs) and the most probable candidates for NEAs of the cometary origin. In t...

  20. 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...

  1. Earth-crossing asteroids - New discoveries

    Science.gov (United States)

    Helin, E. F.

    1982-01-01

    An earth-crossing asteroid is an asteroid whose orbit will intersect the orbit of the earth as a result of secular perturbations. Astronomical observations have led to the discovery of 43 earth-crossing asteroids during the last fifty years. Nearly sixty percent of these were found in the decade 1971-1981. Noteworthy results of the last decade are discussed, taking into account the Aten asteroids, accidental rediscoveries, asteroids of possible cometary origin, candidates for rendezvous and sample return missions, and populations and collision rates with earth. The observed earth-crossing asteroids are listed in a table, and the orbits of earth, Mars, and four Atens projected on ecliptic plane are shown.

  2. 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...

  3. 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...

  4. Families classification including multiopposition asteroids

    Science.gov (United States)

    Milani, Andrea; Spoto, Federica; Knežević, Zoran; Novaković, Bojan; Tsirvoulis, Georgios

    2016-01-01

    In this paper we present the results of our new classification of asteroid families, upgraded by using catalog with > 500,000 asteroids. We discuss the outcome of the most recent update of the family list and of their membership. We found enough evidence to perform 9 mergers of the previously independent families. By introducing an improved method of estimation of the expected family growth in the less populous regions (e.g. at high inclination) we were able to reliably decide on rejection of one tiny group as a probable statistical fluke. Thus we reduced our current list to 115 families. We also present newly determined ages for 6 families, including complex 135 and 221, improving also our understanding of the dynamical vs. collisional families relationship. We conclude with some recommendations for the future work and for the family name problem.

  5. 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

  6. 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.

  7. Asteroid Evolution: Role of Geotechnical Properties

    CERN Document Server

    Sánchez, Paul

    2015-01-01

    This paper presents a brief review and latest results of the work that has been carried out by the Planetary Science community in order to understand that role of the geotechnical properties of granular asteroids (commonly known as "rubble-pile" asteroids) in their formation, evolution and possible disruption. As such, we will touch in aspects of the theoretical and numerical tools that have been used with this objective and how the obtained results compare to the observed asteroids.

  8. ADAM: All-Data Asteroid Modeling

    Science.gov (United States)

    Viikinkoski, Matti; Kaasalainen, Mikko; Durech, Josef

    2015-02-01

    ADAM (All-Data Asteroid Modeling) models asteroid shape reconstruction from observations. Developed in MATLAB with core routines in C, its features include general nonconvex and non-starlike parametric 3D shape supports and reconstruction of asteroid shape from any combination of lightcurves, adaptive optics images, HST/FGS data, disk-resolved thermal images, interferometry, and range-Doppler radar images. ADAM does not require boundary contour extraction for reconstruction and can be run in parallel.

  9. 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

  10. Asteroid Models from Multiple Data Sources

    Science.gov (United States)

    Durech, J.; Carry, B.; Delbo, M.; Kaasalainen, M.; Viikinkoski, M.

    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 three-dimensional 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 three-dimensional models will help to refine our general knowledge of the asteroid population. The physical and surface properties of asteroids, i.e., their spin, three-dimensional shape, density, thermal inertia, and surface roughness, are among the least known of all asteroid properties. Apart from the albedo and diameter, we have access to the whole picture for only a few hundreds of asteroids. These quantities are nevertheless very important to understand, as they affect the nongravitational Yarkovsky effect responsible for meteorite delivery to Earth, as well as the bulk composition and internal structure of asteroids.

  11. Collisional and Rotational Disruption of Asteroids

    Science.gov (United States)

    Walsh, Kevin J.; Michel, Patrick; Richardson, Derek C.

    2011-02-01

    Asteroids are leftover pieces from the era of planet formation that help us understand conditions in the early Solar System. Unlike larger planetary bodies that were subject to global thermal modification during and subsequent to their formation, these small bodies have kept at least some unmodified primordial material from the solar nebula. However, the structural properties of asteroids have been modified considerably since their formation. Thus, we can find among them a great variety of physical configurations and dynamical histories. In fact, with only a few possible exceptions, all asteroids have been modified or completely disrupted many times during the age of the Solar System. This picture is supported by data from space mission encounters with asteroids that show much diversity of shape, bulk density, surface morphology, and other features. Moreover, the gravitational attraction of these bodies is so small that some physical processes occur in a manner far removed from our common experience on Earth. Thus, each visit to a small body has generated as many questions as it has answered. In this review we discuss the current state of research into asteroid disruption processes, focusing on collisional and rotational mechanisms. We find that recent advances in modeling catastrophic disruption by collisions have provided important insights into asteroid internal structures and a deeper understanding of asteroid families. Rotational disruption, by tidal encounters or thermal effects, is responsible for altering many smaller asteroids, and is at the origin of many binary asteroids and oddly shaped bodies.

  12. Asteroid regoliths: The development of a database

    Science.gov (United States)

    Graps, A.

    2014-07-01

    There is a variety of evidence that asteroids, including the smallest asteroids, possess regoliths. This layer is our interface between the asteroid's interior physical processes and its exterior manifestation. By going beyond the remote study of asteroids with Hayabusa's brief touchdown onto Itokowa's surface, scientists, engineers, mission planners have new immediate questions and concerns about the asteroid regolith. For example: What if some asteroid surface features are transient due to dust transport? What are the risks about electrostatically sticky dust? Which alteration process (impact cratering, tectonics, shaking, dust levitation, and space weathering) can best explain the regolith properties of a particular asteroid? To address these questions, a method has been developed which will lead to a database of asteroid regolith properties to aid asteroid investigators. The method is illustrated in the flowchart below. Three types of information is included: spacecraft-based in-situ data, laboratory-based meteorite samples, and telescopic remote data provide a system of cross-checking to increase the accuracy and the probability of gaining new information. Theoretical studies can provide additional cross-checking. A critical perspective, included here, is the assignment of the spatial scales where the bulk density and porosity of an asteroid is related to the average density and porosity of its constituent rocks, which is further distinguished from the average density of the mineral assemblages within the rocks. This presentation will step through the method and provide first regolith database results of the regolith properties: grain density, size, thermal conductivity, porosity, and volume filling factor for the asteroids (1)~Ceres, (2)~Pallas, (21)~Lutetia, and (4)~Vesta.

  13. Asteroid Catalog Using Akari: AKARI/IRC Mid-Infrared Asteroid Survey

    Science.gov (United States)

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

    2011-10-01

    We present the results of an unbiased asteroid survey in the mid-infrared wavelength region with the Infrared Camera (IRC) on board 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 a 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 new brand of asteroid catalog, named the Asteroid Catalog Using AKARI (AcuA), which contains 5120 objects, about twice as many as the IRAS asteroid catalog. The catalog objects comprise 4953 main belt asteroids, 58 near-Earth asteroids, and 109 Jovian Trojan asteroids. The catalog is publicly available via the Internet.

  14. Migration of Near Earth Asteroid to Jovian-Crosser Asteroid:Case Study 3552 Don Quixote

    CERN Document Server

    Siregar, Suryadi

    2010-01-01

    It is generally recognized that main-belt asteroids (MBAs) and nuclei of extinct comets are the two main sources for the Near-Earth-Asteroids (NEAs). Theoretical studies of NEAs dynamics and numerical modelling of their orbital motions showed that the resonance mechanism for supplying NEAs is quite sufficient to sustain this population. Asteroid 1983 SA, also known as 3552 Don Quixote, is one of Near Earth Asteroids (NEAs) and the most probable candidates for NEAs of the cometary origin. In this work, an investigation on the evolution of the orbit is done by using the SWIFT subroutine package, where the gravitational perturbations of eight planets: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune are considered. Migration of asteroid 3552 Don Quixote from Near Earth Asteroids (NEAs) to Jovian-crosser asteroid is found.

  15. Organic matter on asteroid 130 Elektra

    Science.gov (United States)

    Cruikshank, D. P.; Brown, R. H.

    1987-01-01

    Infrared absorption spectra of a low-albedo water-rich asteroid appear to show a weak 3.4-micrometer carbon-hydrogen stretching mode band, which suggests the presence of hydrocarbons on asteroid 130 Elektra. The organic extract from the primitive carbonaceous chondritic Murchison meteorite shows similar spectral bands.

  16. 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-t...

  17. Spitzer Survey of the Karin Cluster Asteroids

    NARCIS (Netherlands)

    Harris, Alan W.; Mueller, M.; Lisse, C.; Cheng, A.; Osip, D.

    2007-01-01

    The Karin cluster is one of the youngest known families of main-belt asteroids, dating back to a collisional event only 5.8 Myr ago. Using the Spitzer Space Telescope we have sampled the thermal continua of 17 Karin cluster asteroids, down to the smallest members discovered so far, in order to deriv

  18. 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...

  19. Distribution and evolution of asteroid rotation rates

    Science.gov (United States)

    Dermott, S. F.; Murray, C. D.

    1984-01-01

    Data on the rotational characteristics of more than 300 asteroids are currently available, and it is now clear that the distribution of the rotation rates is nonrandom. A plot of rotation rate against asteroid diameter shows large dispersion but is distinctly V-shaped. The minimum of this curve at about 120 km may separate primordial asteroids from their collision products. There is also evidence that rotation rate depends on type classification, and weak evidence that it may also depend on family membership. Recent bias-free observations suggest that the marked rise of rotation rate with decreasing diameter D for those asteroids with D less than 120 km cannot be completely accounted for by observational-selection effects. A significantly large subset of the small asteroids have exceptionally long rotation periods suggestive of either a different nature and origin or a peculiar history. Models that have been proposed to account for these results are discussed.

  20. Asteroids in the Eccentrids meteor system

    Science.gov (United States)

    Terentjeva, A. K.; Barabanov, S. I.

    2016-09-01

    Among 11 673 of near-Earth objects (NEOs), 52 asteroids are identified, which, together with the Eccentrids meteor system, comprise a single population of small bodies of the Solar System with the smallest orbits of high eccentricity. Some features of this unique system of bodies are discussed in this paper. The distribution of perihelion longitudes is studied for the given group of asteroids and compared to that of the Aten asteroids, which are the most similar to the Eccentrids. The dependence is obtained of the character of perihelion longitude distribution on the eccentricities of the NEO orbits. Eight asteroid stream of the Eccentrids are found. The Eccentrids asteroids approaching the Earth's orbit along its whole length in their aphelia can pose a certain hazard for the Earth.

  1. On the Astrid asteroid family

    Science.gov (United States)

    Carruba, V.

    2016-09-01

    Among asteroid families, the Astrid family is peculiar because of its unusual inclination distribution. Objects at a ≃ 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 - sC nodal secular resonance with Ceres, that spreads the inclination of asteroids near its separatrix. As a consequence, the currently observed distribution of the vW 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 the kurtosis of the distribution in vW be reached over the estimated lifetime of the family, we obtained that the thermal conductivity of Astrid family members should be ≃0.001 W m-1 K-1, and that the surface and bulk density should be higher than 1000 kg m-3. Monte Carlo methods simulating Yarkovsky and stochastic Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) evolution of the Astrid family show its age to be T = 140 ± 30 Myr old, in good agreement with estimates from other groups. Its terminal ejection velocity parameter is in the range V_{EJ}= 5^{+17}_{-5} m s-1. Values of VEJ larger than 25 m s-1 are excluded from constraints from the current inclination distribution.

  2. Lightcurve Analysis of Asteroids from Blue Mountains Observatory in 2014

    Science.gov (United States)

    Oey, Julian

    2016-01-01

    Photometric observations of a number of asteroids were done from Blue Mountains Observatory in 2014. The observations were made in support of the binary asteroid and asteroid pairs campaigns by Petr Pravec, and to obtain new data at favorable apparitions for asteroids with poorly defined lightcurves.

  3. Working Group Reports and Presentations: Asteroids

    Science.gov (United States)

    Lewis, John

    2006-01-01

    The study and utilization of asteroids will be an economical way to enable exploration of the solar system and extend human presence in space. There are thousands of near-earth objects (NEOs) that we will be able to reach. They offer resources, transportation, and exploration platforms, but also present a potential threat to civilization. Asteroids play a catastrophic role in the history of the Earth. Geological records indicate a regular history of massive impacts, which astronomical observations confirm is likely to continue with potentially devastating consequences. However, study and exploration of near earth asteroids can significantly increase advanced warning of an Earth impact, and potentially lead to the technology necessary to avert such a collision. Efforts to detect and prevent cataclysmic events would tend to foster and likely require international cooperation toward a unified goal of self-preservation. Exploration of asteroids will help us to understand our history and perhaps save our future. Besides the obvious and compelling scientific and security drivers for asteroid research and exploration, there are numerous engineering and industrial applications for near-term asteroid exploration. We have strong evidence that some asteroids are metal rich. Some are water and organic rich. They can be reached with a very low fuel cost compared to other solar system destinations. Once we reach them, there are efficient, simple extraction technologies available that would facilitate utilization. In addition, the costs of returning extracted resources from asteroids will be a fraction of the cost to return similar resources from the moon to Low Earth Orbit (LEO). These raw materials, extracted and shipped at relatively low cost, can be used to manufacture structures, fuel, and products which could be used to foster mankind s further exploration of the solar system. Asteroids also have the potential to offer transport to several destinations in the solar system

  4. 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

  5. Dynamical dispersal of primordial asteroid families

    Science.gov (United States)

    Brasil, P. I. O.; Roig, F.; Nesvorný, D.; Carruba, V.; Aljbaae, S.; Huaman, M. E.

    2016-03-01

    Many asteroid families are identified and well characterized all over the main asteroid belt. Interestingly, however, none of them are older than 4 Gyr. Many mechanisms have been proposed to disperse such old primordial asteroid families that presumably have existed, but only very few have really worked. Here we present a plausible mechanism for dispersing primordial asteroid families that is based on the 5-planet instability model known as jumping Jupiter. Using two different evolutions for the jumping-Jupiter model, we have numerically integrated orbits of eight putative primordial families. Our results show that the most important effect on the asteroid families' eccentricity and inclination dispersal is that of the secular resonances, in some cases associated with the mean motion resonances. As for the semimajor axes spreading we find that the principal effect is that of close encounters with the fifth giant planet whose orbit briefly overlaps with (part of) the main belt. Therefore, the existence of a fifth giant planet with the mass comparable with that of Uranus' or Neptune's could contribute in important ways to dispersal of the primordial asteroid families. To have that effect, the interloper planet should go into and considerably interact with the asteroids during the instability phase.

  6. Delivery of meteorites from the asteroid belt

    Science.gov (United States)

    Nolan, Michael Craig

    The process of the delivery of meteorites to the surface of the Earth from plausible source regions such as the asteroid belt is currently understood in general terms, but important uncertainties and conflicts remain to be resolved. Stochastic effects of the rare disruptions of large asteroids on the population of meteorite-sized Earth-crossing asteroids can change the flux and the proportions of compositional types in the infalling meteorite population. These changes can be significant in magnitude over timescales of 108 years. Changes of the order of 1 percent can be expected on timescales of 105-106 y, consistent with small differences between the Antarctic meteorites and modern falls. The magnitude of changes depends strongly on poorly-understood details of collisions. Asteroids 961 Gaspra and 243 Ida were recently imaged by the Galileo spacecraft. I use a numerical hydrocode model to examine the outcomes of various sire impacts into targets the sizes of these asteroids. A shock wave fractures the asteroid in advance of crater excavation flow; thus, for impactors larger than 100 m, impacting at 5.3 km s-1, tensile strength is unimportant in these bodies, whether they are initially intact or are 'rubble piles'. Because of the shock-induced fracture, impact results are controlled by gravity. Therefore these asteroids are much more resistant to catastrophic disruption than predicted by previous estimates, which had assumed that strength was controlling these processes for rock targets. Fracture of km-size asteroids is different from fracture in terrestrial experiments using few-cm targets. The composition distribution of delivered meteorites depends on the outcomes of such asteroid impacts.

  7. A three-parameter asteroid taxonomy

    Science.gov (United States)

    Tedesco, Edward F.; Williams, James G.; Matson, Dennis L.; Veeder, Glenn J.; Gradie, Jonathan C.

    1989-01-01

    Broadband U, V, and x photometry together with IRAS asteroid albedos have been used to construct an asteroid classification system. The system is based on three parameters (U-V and v-x color indices and visual geometric albedo), and it is able to place 96 percent of the present sample of 357 asteroids into 11 taxonomic classes. It is noted that all but one of these classes are analogous to those previously found using other classification schemes. The algorithm is shown to account for the observational uncertainties in each of the classification parameters.

  8. A NEW DYNAMICAL POPULATION OF ASTEROIDS

    Directory of Open Access Journals (Sweden)

    T. Gallardo

    2009-01-01

    Full Text Available We have found approximately 1500 asteroids evolving in the exterior 1:2 resonance with Mars. Looking at the histogram of semimajor axes of the asteroids in the main belt the population can be distinguished as a peak at a ' 2:419 AU. Approximately 400 asteroids are librating around the asymmetric libration centers and about 700 are describing horseshoe trajectories. A strong secular perturbation due to Jupiter and due to Mars' eccentricity time evolution produces switching between libration centers and between librations and horseshoe trajectories. In spite of this strong secular e ect the population remains linked to the resonance over time scales of 108 - 109 years.

  9. 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.

  10. 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.

  11. 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...

  12. 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.

  13. Collisional and Rotational Disruption of Asteroids

    CERN Document Server

    Walsh, Kevin J; Richardson, Derek C

    2009-01-01

    Asteroids are leftover pieces from the era of planet formation that help us understand conditions in the early Solar System. Unlike larger planetary bodies that were subject to global thermal modification during and subsequent to their formation, these small bodies have kept at least some unmodified primordial material from the solar nebula. However, the structural properties of asteroids have been modified considerably since their formation. Thus, we can find among them a great variety of physical configurations and dynamical histories. In fact, with only a few possible exceptions, all asteroids have been modified or completely disrupted many times during the age of the Solar System. This picture is supported by data from space mission encounters with asteroids that show much diversity of shape, bulk density, surface morphology, and other features. Moreover, the gravitational attraction of these bodies is so small that some physical processes occur in a manner far removed from our common experience on Earth....

  14. Asteroid Lightcurves from the Preston Gott Observatory

    Science.gov (United States)

    Clark, Maurice

    2012-04-01

    Results of analysis of CCD photometry observations obtained at the Preston Gott Observatory of asteroids 970 Primula, 3015 Candy, 3751 Kiang, 6746 Zagar, 7750 McEwen, 10046 Creighton, and 19251 Totziens are presented.

  15. 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.

  16. Chelyabinsk: Portrait of an asteroid airburst

    International Nuclear Information System (INIS)

    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

  17. 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.

  18. 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

  19. 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...

  20. An ISU study of asteroid mining

    Science.gov (United States)

    Burke, J. D.

    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.

  1. 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...

  2. 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...

  3. Lightcurves of the Karin family asteroids

    Science.gov (United States)

    Yoshida, Fumi; Ito, Takashi; Dermawan, Budi; Nakamura, Tsuko; Takahashi, Shigeru; Ibrahimov, Mansur A.; Malhotra, Renu; Ip, Wing-Huen; Chen, Wen-Ping; Sawabe, Yu; Haji, Masashige; Saito, Ryoko; Hirai, Masanori

    2016-05-01

    The Karin family is a young asteroid family formed by an asteroid breakup 5.8 Myr ago. Since the members of this family probably have not experienced significant orbital or collisional evolution yet, it is possible that they still preserve properties of the original family-forming event in terms of their spin state. We carried out a series of photometric observations of the Karin family asteroids, and here we report on the analysis of the lightcurves including the rotation period of eleven members. The mean rotation rate of the Karin family members turned out to be much lower than those of near-Earth asteroids or small main belt asteroids (diameter D 130 km). We investigated a correlation between the peak-to-trough variation and the rotation period of the eleven Karin family asteroids, and found a possible trend that elongated members have lower spin rates, and less elongated members have higher spin rates. However, this trend has to be confirmed by another series of future observations.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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

  9. 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

  10. Near-Earth Asteroid Scout

    Science.gov (United States)

    McNutt, Leslie; Johnson, Les; Clardy, Dennon; Castillo-Rogez, Julie; Frick, Andreas; Jones, Laura

    2014-01-01

    Near-Earth Asteroids (NEAs) are an easily accessible object in Earth's vicinity. Detections of NEAs are expected to grow in the near future, offering increasing target opportunities. As NASA continues to refine its plans to possibly explore these small worlds with human explorers, initial reconnaissance with comparatively inexpensive robotic precursors is necessary. Obtaining and analyzing relevant data about these bodies via robotic precursors before committing a crew to visit a NEA will significantly minimize crew and mission risk, as well as maximize exploration return potential. The Marshall Space Flight Center (MSFC) and Jet Propulsion Laboratory (JPL) are jointly examining a mission concept, tentatively called 'NEA Scout,' utilizing a low-cost CubeSats platform in response to the current needs for affordable missions with exploration science value. The NEA Scout mission concept would be a secondary payload on the Space Launch System (SLS) Exploration Mission 1 (EM-1), the first planned flight of the SLS and the second un-crewed test flight of the Orion Multi-Purpose Crew Vehicle (MPCV).

  11. SOFIA observations of dark asteroids: Evidence for hydrated minerals on asteroidal surfaces?

    Science.gov (United States)

    McAdam, Margaret; Sunshine, Jessica M.; Kelley, Michael S. P. T.

    2015-11-01

    We present results from recent SOFIA+FORCAST observations of three primitive asteroids and compare these to archived Spitzer Space Telescope (Spitzer) observations of similar objects. Three asteroids from a total of 12 have been observed with SOFIA+FORCAST in our Cycle-3 campaign. Currently, we have observed asteroids 38 Leda, 194 Prokne with both G111 and G227 grisms and asteroid 266 Aline with G227. Both wavelength regions (G111: 8.5-13.5-μm and G227: 17.6-27.7) have recently been shown to contain spectral features directly related degree of alteration of primitive meteorites, including unaltered CO and CV meteorites (McAdam, et al., 2015a ,b). Spectral features in the 17.6-27.7-μm region can be indicative of olivine (19.5-μm), hydrated minerals (21-μm) and silica glass (22-μm). Spitzer observed eight large, primitive, main-belt asteroids using both low-resolution modes (short-low, SL and long-low, LL) of the Infrared Spectrograph (IRS) covering 8.5-38-μm. Additionally, Spitzer observed 22 dark primitive asteroids in the 8.5-13.5-μm region. Asteroids observed with Spitzer fall into three categories: asteroids with a 12-μm feature of 1-5% depth, interpreted as ~60-70% hydrated minerals (McAdam, et al., 2015a) asteroids with a broader 12-13-μm feature with strengths ranging from 4-6% with potential features between 19-22-μm (where observed) and asteroids with a strong 13-μm feature (5-10%), 15-μm and potentially 19-22-μm features (where observed) interpreted as olivine-rich. However, the uncertain calibration at the edges of the LL spectral orders complicates feature identification. 194 Prokne has a feature ~12-13-μm feature and potentially a broad feature between 20-22-μm. This is consistent with primitive asteroids observed with Spitzer that are interpreted as hydrated mineral-bearing. 38 Leda is largely featureless at the noise limit of the spectrum with a potential feature at 25-μm, unlike asteroids observed by Spitzer. 266 Aline has a weak

  12. 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 Space Administration. ACTION: Notice of Continuation of public conference to examine ideas in response... Administration announces that the agency will resume the NASA Asteroid Initiative Idea Synthesis...

  13. CCD-Photometry and Pole Coordinates for Eight Asteroids

    Science.gov (United States)

    Shevchenko, V. G.; Tungalag, N.; Chiorny, V. G.; Gaftonyuk, N. M.; Krugly, Y. N.; Harris, A. W.; Young, J. W.

    2012-05-01

    The long time photometric observations were carried out for eight asteroids: (122) Gerda, (153) Hilda, (190) Ismene, (221) Eos, (411) Xanthe, (679) Pax, (700) Auravictrix, (787) Moskva. For the observed asteroids were determined new pole coordinates.

  14. 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...

  15. Asteroid rotation rates depend on diameter and type

    Energy Technology Data Exchange (ETDEWEB)

    Dermott, S.F.; Murray, C.D. (Cornell Univ., Ithaca, NY (USA). Center for Radiophysics and Space Research)

    1982-04-01

    The rotational frequency of main-belt asteroids is shown here to depend on both asteroidal type and diameter. If asteroids of any one diameter are considered then, on average, M asteroids rotate faster than S asteroids which in turn rotate faster than C asteroids. This shows that asteroids which have been classified by their surface properties alone have different bulk properties. For all three types, although the dispersions of the frequencies are large, it is proved that the mean frequency increases linearly with the mean diameter. In both the C and S plots of mean rotational frequency against mean diameter there are discontinuities at diameters approximately equal to 125 km and approximately equal to 105 km, respectively, which may differentiate primordial asteroids from their collisional products.

  16. 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...

  17. Brazil Nuts on Eros: Size-Sorting of Asteroid Regolith

    Science.gov (United States)

    Asphaug, E.; King, P. J.; Swift, M. R.; Merrifield, M. R.

    2001-01-01

    We consider the hypothesis that frequent cratering produces size- or compositionally-sorted asteroid regolith, affecting the structure, texture, and in extreme cases the shape of asteroids. Additional information is contained in the original extended abstract.

  18. 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...

  19. Philosophy and updating of the asteroid photometric catalogue

    Science.gov (United States)

    Magnusson, Per; Barucci, M. Antonietta; Capria, M. T.; Dahlgren, Mats; Fulchignoni, Marcello; Lagerkvist, C. I.

    1992-01-01

    The Asteroid Photometric Catalogue now contains photometric lightcurves for 584 asteroids. We discuss some of the guiding principles behind it. This concerns both observers who offer input to it and users of the product.

  20. The Strength of Rubble Pile Asteroids

    Science.gov (United States)

    Scheeres, D. J.; Sanchez, P.

    2012-12-01

    The rubble pile hypothesis for small asteroids in the Near Earth and Main Belt populations have been driven by several factors, including the observed high porosity of those bodies whose mass have been measured, the evident limitation on spin rate of asteroids larger than ~500 meters, and direct observation of the surface morphology of these bodies. Given these observations, it has been presumed that small asteroids should evolve as if they were cohesionless collections of grains. Detailed geophysical analysis of these bodies by Holsapple (Icarus 2010) show that cohesionless bodies will evolve under the addition of angular momentum by the YORP effect into more distended and, paradoxically, more slowly rotating bodies. Additional analysis in Holsapple (Icarus 2007) has shown that cohesional strength within a rubble pile could strengthen a collection of grains to the point where they could sustain rapid rotation. In our current talk we use the above as a starting point and incorporate new observations of the asteroid morphology driven by recent analysis of asteroid Itokawa by the Hayabusa science team and research on the mechanics of grains in the space environment (Scheeres et al. 2010). Analysis of images of Itokawa determined a measured size distribution of 1/d^3 for larger grains on asteroid Itokawa (Michikami et al., Earth Planets Space, 60, 13-20, 2008). Analysis of the sample shows the presence of micron sized dust on that asteroid's surface (Tsuchiyama et al., Science 333, 1125, 2011). Combining these observations provides a global indication of grain distribution within rubble piles. Even assuming a less steep distribution of 1/d^2 for dust grains smaller than 1 mm in size, the interior of Itokawa should still be dominated by the finest dust grains, with the mean grain size equal to ~ twice the smallest grain in the distribution. One implication of this result is that fines are present on the surface of the rubble pile Itokawa and thus should be distributed

  1. Flyght Dynamics of Artificial Satellite of the Minor Asteroid

    Science.gov (United States)

    Zakharov, Alexander; Eismont, Natan; Ledkov, Anton; Simonov, Alexander; Pol, Vadim

    During last years the scientific interest to the asteroid is constantly growing. It may be explained by different reasons. One of the most important from them is confirmation of the fact that the asteroids present the real hazard to the Earth. The Chelyabinsk event demonstrates strong in support of this statement. Besides, the asteroids exploration promises to supply new data for understanding of the solar system origin and evolution. And the projects aimed to reach this goal have begun from the NASA NEAR mission to Eros. It was the first one when the spacecraft was landed on the surface of the asteroid. The other successive mission was fulfilled by JAXA with Hayabusa spacecraft which has returned to the Earth soil samples of Itokawa asteroid. In the nearest future the mission to RQ 36 asteroid is planned supposing landing and soil samples return. Unavoidable phase of such missions is the spacecraft flight in vicinity of the target asteroid, for example on the asteroid satellite orbit. It should be mentioned that quite visible number of asteroids has geometric form which is far from being sphere. Accordingly the gravity field of such asteroid cannot be presented as the one close to sphere. The problem is that prior to the mission to the asteroid one cannot receive good enough knowledge of its gravity field and even its gravity field constant. In the paper the flight dynamics problem of spacecraft moving along asteroid satellite orbit is explored. It is supposed that the asteroid is comparatively small with diameter (maximum size) about 300 m, like Apophis asteroid has, or less. To approximate the gravity field of asteroid the last is considered as totality of mass points. We assume such approach as more simple and effective as compared with the commonly accepted use of Legendre polynomial expansion. Different orbits near asteroid are analyzed with the sets of orbital parameters determining the size of orbit, its shape and position with respect to the Sun. The goal

  2. 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...

  3. Detecting Mass Loss in Main Belt Asteroids

    Science.gov (United States)

    Sandberg, Erik; Rajagopal, Jayadev; Ridgway, Susan E.; Kotulla, Ralf C.; Valdes, Francisco; Allen, Lori

    2016-01-01

    Sandberg, E., Rajagopal, J., Ridgway, S.E, Kotulla, R., Valdes, F., Allen, L.The Dark Energy Camera (DECam) on the 4m Blanco telescope at the Cerro Tololo Inter-American Observatory (CTIO) is being used for a survey of Near Earth Objects (NEOs). Here we attempt to identify mass loss in main belt asteroids (MBAs) from these data. A primary motivation is to understand the role that asteroids may play in supplying dust and gas for debris disks. This work focuses on finding methods to automatically pick out asteroids that have qualities indicating possible mass loss. Two methods were chosen: looking for flux above a certain threshold in the asteroid's radial profile, and comparing its PSF to that of a point source. After sifting through 490 asteroids, several have passed these tests and should be followed up with a more rigorous analysis.Sandberg was supported by the NOAO/KPNO Research Experience for Undergraduates (REU) Program which is funded by the National Science Foundation Research Experiences for Undergraduates Program (AST-1262829)

  4. 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.

  5. A Fast Ellipsoid Model for Asteroids Inverted From Lightcurves

    OpenAIRE

    Lu, Xiaoping; Zhao, Haibin; 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 ...

  6. 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.

  7. 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.

  8. 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

  9. Modeling of asteroidal dust production rates

    Science.gov (United States)

    Durda, Daniel D.; Dermott, Stanley F.; Gustafson, Bo A. S.

    1992-01-01

    The production rate of dust associated with the prominent Hirayama asteroid families and the background asteroidal population are modeled with the intent of using the families as a calibrator of mainbelt dust production. However, the dust production rates of asteroid families may be highly stochastic; there is probably more than an order of magnitude variation in the total area of dust associated with a family. Over 4.5 x 10(exp 9) years of collisional evolution, the volume (mass) of a family is ground down by an order of magnitude, suggesting a similar loss from the entire mainbelt population. Our collisional models show that the number of meteoroids deliverable to Earth also varies stochastically, but only by a factor of 2 to 3.

  10. 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.

  11. 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...

  12. 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.

  13. 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.

  14. Dust bands in the asteroid belt

    Science.gov (United States)

    Sykes, Mark V.; Greenberg, Richard; Dermott, Stanley F.; Nicholson, Philip D.; Burns, Joseph A.

    1989-01-01

    This paper describes the original IRAS observations leading to the discovery of the three dust bands in the asteroid belt and the analysis of data. Special attention is given to an analytical model of the dust band torus and to theories concerning the origin of the dust bands, with special attention given to the collisional equilibrium (asteroid family), the nonequilibrium (random collision), and the comet hypotheses of dust-band origin. It is noted that neither the equilibrium nor nonequilibrium models, as currently formulated, present a complete picture of the IRAS dust-band observations.

  15. 6384 Kervin: A Possible Hungaria Binary Asteroid

    Science.gov (United States)

    Warner, Brian D.; Aznar Macia, Amadeo

    2016-04-01

    Analysis of CCD photometric observations in late 2015 of the Hungaria asteroid 6384 Kervin indicates that it may be a binary asteroid with a primary lightcurve of P1 = 3.6194 ± 0.0001 h, A1 = 0.06 ± 0.01 mag. The secondary lightcurve parameters are P2 = 15.94 ± 0.01 h, A2 = 0.03 ± 0.01 mag. No mutual events (occultations or eclipses) were observed. However, other indicators give an estimated diameter ratio on the order of Ds/Dp ~ 0.3, possibly greater.

  16. 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.

  17. Damage from the impacts of small asteroids

    Energy Technology Data Exchange (ETDEWEB)

    Hills, J.G.; Goda, M.P.

    1996-08-15

    The fragmentation of a small asteroid in the atmosphere greatly increases its aerodynamic drag and rate of energy dissipation. The differential atmospheric pressure across it disperses its fragments at a velocity that increases with atmospheric density and impact velocity and decreases with asteroid density. Extending our previous work, we use a spherical atmosphere and a fitted curve to its density profile to find the damage done by an asteroid entering the atmosphere at various zenith angles. In previous work we estimated the blast damage by scaling from data on nuclear explosions in the atmosphere during the 1940s, 1950s and early 1960s. This underestimated the blast from asteroid impacts because nuclear fireballs radiate away a larger fraction of their energy than do meteors, so less of their energy goes into the blast wave. We have redone the calculations to allow for this effect. We have found the area of destruction around the impact point in which the over pressure in the blast wave exceeds 4 pounds/inch{sup 2} = 2.8 X 10{sup 5} dynes/cm{sup 3}, which is enough to knock over trees and destroy buildings. About every 100 years an impactor should blast an area of 300 km{sup 2} or more somewhere on the land area of Earth. The optical flux from asteroids 60 meters or more in diameter is enough to ignite pine forests. However, the blast from an impacting asteroid goes beyond the radius within which the fire starts. It tends to blow out the fire, so it is likely that the impact will char the forest (as at Tunguska), but it will not produce a sustained fire. Because of the atmosphere, asteroids less than about 200 m in diameter are not effective in producing craters and earthquakes. They are also not effective in producing water waves and tsunami in ocean impacts. Tsunami is probably the most devastating type of damage for asteroids that are between 200 meters and 1 km in diameter.

  18. 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

  19. 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.

  20. Angular Momentum Transfer in Catastrophic Asteroid Impacts

    Science.gov (United States)

    Love, S. G.; Ahrens, T. J.

    1996-09-01

    Incomplete knowledge of angular momentum transfer in asteroid impacts has hampered efforts to deduce asteroid collisional histories from their rotation rates. This problem traditionally has been investigated using impact experiments on cm-scale, strength-dominated targets. Recent evidence, however, indicates that impacts on asteroids of km size and larger may be controlled by gravity rather than strength, and that the analogy to laboratory impacts may not hold. Accordingly, we have modelled catastrophic impacts on gravitating asteroids to better understand angular momentum transfer in such events. We employ a 3--D, strengthless, gravitating SPH computer code. Target bodies are 10 to 1000 km in diameter and do not initially rotate. Impact speeds are 3--7 km/s; impact angles are 15--75(deg) . Each target is composed of 1791 mass elements: spatial resolution is coarse but acceptable for large scale energy transfer. We simulate the hydrodynamic phase of each impact, after which particle motions are ballistic and treated analytically. Escaping particles have kinetic energy greater than the gravitational energy binding them to the rest of the system; the others reaccrete to form a ``rubble pile'' which is assumed spherical. The rubble pile's size, mass, and angular momentum define its rotation rate. Spin rates for ejected fragments cannot be determined. The target's final spin period depends on the impact angle and the fraction of target mass ejected, but not on impact speed or target size in the ranges tested. The lack of size dependence cannot explain the observed excess of slowly rotating asteroids of ~ 100 km diameter. The fraction of projectile angular momentum retained by the target varies dramatically with impact speed and angle and with target size and fraction of mass removed, complicating its use in models where collision geometry varies. The final spin period of an asteroid losing 50% of its mass is 6--10 hours, comparable to the asteroidal mean of 8 hours

  1. New Asteroid Models Based on Combined Dense and Sparse Photometry

    Science.gov (United States)

    Hanuš, Josef; Durech, J.

    2010-10-01

    For thousands of asteroids we investigated several ten thousands of sparse photometric data from astrometric projects. These data are available on AstDyS server (Asteroids -- Dynamic Site, http://hamilton.dm.unipi.it). We picked 7 astrometric surveys and used their calibrated photometry in lightcurve inversion method for determination of asteroid's convex shapes and rotational states. We present nearly 100 new asteroid models derived from combined dense and sparse data sets, where sparse photometry is taken from AstDyS server and dense lightcurves are from the Uppsala Asteroid Photometric Catalogue (UAPC) and from several individual observers.

  2. Asteroid Shape and Spin Axis Modeling Via Light Curve Inversion

    Science.gov (United States)

    Friz, Paul; Gokhale, V.

    2013-01-01

    We present light curves and shape and spin axis models for the five asteroids: 291 Alice, 281 Lucretia, 321 Florentina, 714 Ulula, and 3169 Ostro. These models were obtained using data taken from the Truman Observatory, the Asteroid Photometric Catalogue, and the Minor Planet Center. Knowledge of individual asteroids shapes and spin axes is vital to understanding the solar system. However, currently only 213 out of the 500,000 asteroids with known orbits have been modeled. By taking many light curves of asteroids over several apparitions it is possible to determine their shapes and spin axes by a process known as light curve inversion.

  3. 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.

  4. 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.

  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. 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.

  7. 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...

  8. Lightcurves of the Karin family asteroids

    CERN Document Server

    Yoshida, Fumi; Dermawan, Budi; Nakamura, Tsuko; Takahashi, Shigeru; Ibrahimov, Mansur A; Malhotra, Renu; Ip, Wing Huen; Chen, Wen Ping; Sawabe, Yu; Haji, Masashige; Saito, Ryoko; Hirai, Masanori; Miyasaka, Seidai; Fukushima, Hideo; Sato, Hideo; Sato, Yusuke

    2012-01-01

    The Karin family is the first recognized very young asteroid family that was created by an asteroid breakup only 5.8 Myr ago. As the members of this family probably have not experienced significant orbital or collisional evolution yet, it is possible that they still preserve properties of the original collisional event in terms of their rotational status and surface color. We have been carrying out a series of photometric observations of the Karin family asteroids, and here we report the analysis result of lightcurves including the rotation period of eleven members as well as those of an interloper asteroid: (832) Karin, (4507) 1990 FV (an interloper), (7719) 1997 GT36, (10783) 1999 RB9, (11728) Einer, (13765) Nansmith, (16706) Svojsik, (28271) 1999 CK16, (40917) 1999 TR171, (43032) 1999 VR26, (69880) 1998 SQ81, and (71031) 1999 XE68. As for four of them we estimated their absolute magnitudes H_R and the slope parameter G_R of the solar phase curves: (832) Karin, (4507) 1990 FV, (13765) Nansmith, and (69880) ...

  9. 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.

  10. 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

    2009-01-01

    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. PMID:19129845

  11. 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.

  12. The infrared spectrum of asteroid 433 Eros

    Science.gov (United States)

    Larson, H. P.; Fink, U.; Treffers, R. R.; Gautier, T. N., III

    1976-01-01

    The mineralogical composition of asteroid Eros has been determined from its infrared spectrum (0.9-2.7 micrometers; 28/cm resolution). Major minerals include metallic Ni-Fe and pyroxene; no spectroscopic evidence for olivine or plagioclase feldspar was found. The IR spectrum of Eros is most consistent with a stony-iron composition.

  13. Polyhedron tracking and gravity tractor asteroid deflection

    Science.gov (United States)

    Ummen, N.; Lappas, V.

    2014-11-01

    In the wake of the Chelyabinsk airburst, the defense against hazardous asteroids is becoming a topic of high interest. This work improves the gravity tractor asteroid deflection approach by tracking realistic small body shapes with tilted ion engines. An algorithm for polyhedron tracking was evaluated in a fictitious impact scenario. The simulations suggest a capability increase up to 38.2% with such improved tilting strategies. The long- and short-term effects within polyhedron tracking are illustrated. In particular, the orbital reorientation effect is influential when realistic asteroid shapes and rotations are accounted for. Also analyzed is the subject of altitude profiles, a way to tailor the gravity tractor performance, and to achieve a steering ability within the B-plane. A novel analytical solution for the classic gravity tractor is derived. It removes the simulation need for classic tractor designs to obtain comparable two body model Δv figures. This paper corroborates that the asteroid shape can be exploited for maximum performance. Even a single engine tilt adjustment at the beginning of deflection operations yields more deflection than a fixed preset tilt.

  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. 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...

  17. 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.

  18. 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

  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

  20. 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.

  1. Numerical Studies of Dust Distribution around Small Asteroids

    Science.gov (United States)

    Yu, W.; Wang, J.; Han, D.; Chou, K.

    2015-12-01

    While the dynamics of dust transport around an airless body has been a focused area of research in recent years, various challenging aspects still remain to be addressed. This paper presents an investigation of charged dust transport and distribution around small asteroids utilizing two newly developed numerical models and laboratory measurements of dust layer charging in a simulated asteroid plasma environment. The first model is a full particle Particle-in-Cell (PIC) model to simulate plasma flow around an asteroid and calculate surface charging self-consistently from charge deposition on asteroid. A major feature of this model is that the asteroid surface is treated as an "interface" between two mediums rather than a boundary, and the simulation domain includes not only the plasma but also the entire asteroid. An immersed-finite-element field solver is applied which calculates both the surface floating potential and the electric field inside the asteroid directly from local charge deposition. The material properties of asteroid are also explicitly included in the simulation. Results from PIC simulations of asteroid-plasma interactions, along with laboratory measurements of dust charge-to-mass ratio under a simulated asteroid surface charging environment, are fed into a dust dynamics model to simulate charged dust levitation, transport and distribution. In addition to electrostatic and gravitational forces, the dynamics of dust surface impacts and asteroid body rotation are also included in the model. We discuss the effects of asteroid composition and space plasma environments on dust levitation and transport. We present simulation results of dust distribution around several different types of small asteroids.

  2. Another Option for the Asteroid Sample of the Asteroid Redirect Mission

    Science.gov (United States)

    Hou, Xiyun; Tang, Jingshi; Liu, Lin; Xin, Xiaosheng

    2016-07-01

    The asteroid redirect mission (ARM) consists of two phases: the asteroid redirect robotic mission (ARRM) and the asteroid redirect crewed mission (ARCM). The ARRM phase aims at capturing a boulder from the surface of an asteroid of hundred meters in diameter and returning it back to the Earth-Moon system. Currently, the option for the orbit of the returned sample is a large lunar distant retrograde orbit (LDRO) around the Moon. After the sample is returned to this LDRO, then the ARCM phase will send astronauts to the sample. The total energy cost consists of two parts: (1) from the orbit of an near-Earth asteroid to the LDRO, here as part I; (2) from the parking low Earth orbit (LEO) to the LDRO, here as part II. In the authors' work for stable motions in the real Earth-Moon system, we found that there are stable motions around the triangular libration points (TLP). Theoretically, these orbits can also be used as candidate orbits to hold the returned sample. Our previous preliminary works show that the energy of sending a manned probe from the LEO to these orbits is comparable to the option of sending it from the LEO to the LDRO. Besides, it's also possible for the sample to be returned from the orbit of a near-Earth asteroid to these stable orbits, with very small delta-V corrections. In this work, we'll study the energy cost of this option (i.e., using the stable orbits around the TLP as the orbits for the asteroid sample) in detail and compare this option with the LDRO option.

  3. 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.

  4. Tracing meteorite source regions through asteroid spectroscopy

    Science.gov (United States)

    Thomas, Cristina Ana

    By virtue of their landing on Earth, meteorites reside in near-Earth object (NEO) orbits prior to their arrival. Thus the population of observable NEOs, in principle, gives the best representation of meteorite source bodies. By linking meteorites to NEOs, and linking NEOs to their most likely main-belt source locations, we seek to gain insight into the original solar system formation locations for different meteorite classes. To forge the first link between meteorites and NEOs, we have developed a three dimensional method for quantitative comparisons between laboratory measurements of meteorites and telescopic measurements of near-Earth objects. We utilize meteorite spectra from the Reflectance Experiment Laboratory (RELAB) database and NEO data from the SpeX instrument on the NASA Infrared Telescope Facility (IRTF). Using the Modified Gaussian Model (MGM) as a mathematical tool, we treat asteroid and meteorite spectra identically in the calculation of 1-micron and 2-micron geometric band centers and their band area ratios (BARs). Using these identical numerical parameters we quantitatively compare the spectral properties of S-, Sq-, Q- and V-type NEOs with the spectral properties of the meteorites in the H, L, LL and HED meteorite classes. For each NEO spectrum, we assign a set of probabilities for it being related to each of these meteorite classes. Our NEO- meteorite correlation probabilities are then convolved with NEO-source region probabilities to yield a final set of meteorite-source region correlations. An apparent (significant at the 2.1-sigma level) source region signature is found for the H chondrites to be preferentially delivered to the inner solar system through the 3:1 mean motion resonance. A 3:1 resonance H chondrite source region is consistent with the short cosmic ray exposure ages known for H chondrites. The spectroscopy of asteroids is subject to several sources of inherent error. The source region model used a variety of S-type spectra without

  5. 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.

  6. 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

    Context. The shapes and spin states of asteroids observed with photometric techniques can be reconstructed using the lightcurve inversion method. The resultant models can then be confirmed or exploited further by other techniques, such as adaptive optics, radar, thermal infrared, stellar occultat......Context. The shapes and spin states of asteroids observed with photometric techniques can be reconstructed using the lightcurve inversion method. The resultant models can then be confirmed or exploited further by other techniques, such as adaptive optics, radar, thermal infrared, stellar...... 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...

  7. Asteroid occultations today and tomorrow: toward the GAIA era

    CERN Document Server

    Tanga, P

    2008-01-01

    Context: Observation of star occultations is a powerful tool to determine shapes and sizes of asteroids. This is key information necessary for studying the evolution of the asteroid belt and to calibrate indirect methods of size determination, such as the models used to analyze thermal infrared observations. Up to now, the observation of asteroid occultations is an activity essentially secured by amateur astronomers equipped with small, portable equipments. However, the accuracy of the available ephemeris prevents accurate predictions of the occultation events for objects smaller than ~100 km. Aims: We investigate current limits in predictability and observability of asteroid occultations, and we study their possible evolution in the future, when high accuracy asteroid orbits and star positions (such as those expected from the mission Gaia of the European Space Agency) will be available. Methods: We use a simple model for asteroid ephemeris uncertainties and numerical algorithms for estimating the limits impo...

  8. MICROLENS SURVEYS ARE A POWERFUL PROBE OF ASTEROIDS

    International Nuclear Information System (INIS)

    While of order of a million asteroids have been discovered, the number in rigorously controlled samples that have precise orbits and rotation periods, as well as well-measured colors, is relatively small. In particular, less than a dozen main-belt asteroids with estimated diameters D < 3 km have excellent rotation periods. We show how existing and soon-to-be-acquired microlensing data can yield a large asteroid sample with precise orbits and rotation periods, which will include roughly 6% of all asteroids with maximum brightness I < 18.1 and lying within 10° of the ecliptic. This sample will be dominated by small and very small asteroids, down to D ∼ 1 km. We also show how asteroid astrometry could turn current narrow-angle OGLE proper motions of bulge stars into wide-angle proper motions. This would enable one to measure the proper-motion gradient across the Galactic bar.

  9. 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.

  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. 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.

  12. Cratering statistics on asteroids: Methods and perspectives

    Science.gov (United States)

    Chapman, C.

    2014-07-01

    Crater size-frequency distributions (SFDs) on the surfaces of solid-surfaced bodies in the solar system have provided valuable insights about planetary surface processes and about impactor populations since the first spacecraft images were obtained in the 1960s. They can be used to determine relative age differences between surficial units, to obtain absolute model ages if the impactor flux and scaling laws are understood, to assess various endogenic planetary or asteroidal processes that degrade craters or resurface units, as well as assess changes in impactor populations across the solar system and/or with time. The first asteroid SFDs were measured from Galileo images of Gaspra and Ida (cf., Chapman 2002). Despite the superficial simplicity of these studies, they are fraught with many difficulties, including confusion by secondary and/or endogenic cratering and poorly understood aspects of varying target properties (including regoliths, ejecta blankets, and nearly-zero-g rubble piles), widely varying attributes of impactors, and a host of methodological problems including recognizability of degraded craters, which is affected by illumination angle and by the ''personal equations'' of analysts. Indeed, controlled studies (Robbins et al. 2014) demonstrate crater-density differences of a factor of two or more between experienced crater counters. These inherent difficulties have been especially apparent in divergent results for Vesta from different members of the Dawn Science Team (cf. Russell et al. 2013). Indeed, they have been exacerbated by misuse of a widely available tool (Craterstats: hrscview.fu- berlin.de/craterstats.html), which incorrectly computes error bars for proper interpretation of cumulative SFDs, resulting in derived model ages specified to three significant figures and interpretations of statistically insignificant kinks. They are further exacerbated, and for other small-body crater SFDs analyzed by the Berlin group, by stubbornly adopting

  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....... Although the telescope based research offers precise orbital information, it is limited to the brighter, larger objects, and taxonomy as well as morphology resolution is limited. Conversely, dedicated missions offer detailed surface mapping in radar, visual, and prompt gamma, but only for a few selected...... 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. 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.

  15. Noble gases in ancient asteroidal atmospheres

    Science.gov (United States)

    Swindle, Timothy D.

    1993-01-01

    Analytical and numerical results presented here suggest that acceleration of photoions by the solar wind motional field is a significant loss process for Xe on asteroids about 200 km in radius or larger, if the Xe is thermalized by its interactions with the surface. For Ar, photoion acceleration can only become important for asteroids nearly 500 km in radius. Thus photoion acceleration, previously invoked for lunar samples, could be responsible for excess fission-produced Xe found associated with solar wind Xe in howarditic meteorites. The lack of such Xe in other types of meteorites may reflect either smaller parent bodies or later times of regolith exposure. Similarly, the failure to observe solar-wind-associated radiogenic Ar-40 in meteorites is consistent with the much smaller likelihood that Ar will be photoionized.

  16. Speckle interferometry of asteroids. I - 433 Eros

    Science.gov (United States)

    Drummond, J. D.; Cocke, W. J.; Hege, E. K.; Strittmatter, P. A.; Lambert, J. V.

    1985-01-01

    Analytical expressions are derived for the semimajor and semiminor axes and orientation angle of the ellipse projected by a triaxial asteroid, and the results are applied speckle-interferometry observations of the 433 Eros asteroid. The expressions were calculated as functions of the dimensions and pole of the body and of the asterocentric position of the earth and the sun. On the basis of the analytical expressions, the dimensions of 433 Eros are obtained. The light curve from December 18, 1981 is compared to the dimensions to obtain a geometric albedo of 0.156 (+ or - 0.010). A series of two-dimensional power spectra and autocorrelation functions for 433 Eros show that it is spinning in space.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. Pole orientation, sidereal period, and sense of rotation of asteroids

    Science.gov (United States)

    Taylor, R. C.; Gehrels, T.

    1986-01-01

    Pole orientations of asteroids were determined. The method, called photometric astrometry, takes precise epochs of lightcurves into account. Pole determination research on asteroids 532 Herculina, 45 Eugenia, and 3 Juno continues. Discrepancies between various pole determination techniques presently being used are analyzed. The study of asteroid shapes and creating a generalized master pole determination technique also continues which will incorporate the best features of several current methods.

  3. NEA 2015 VY105: A New Tumbling Asteroid

    Science.gov (United States)

    Carbognani, Albino; Buzzi, Luca

    2016-04-01

    We present the results of photometric observations on near-Earth asteroid (NEA) 2015 VY105. Lightcurve analysis shows that it is a tumbling asteroid with synodic rotation periods P1 = 0.0386 ± 0.0001 h with amplitude A1 = 0.96 mag and P2 = 0.061 ± 0.001 h with amplitude A2 = 0.57 mag. After 2008 TC3, this NEA is the fastest and smallest tumbling asteroid.

  4. Orbital perturbation analysis of earth-crossing asteroids

    OpenAIRE

    Knudson, Wade E.

    1995-01-01

    Earth Crossing Asteroids (ECAs) are those asteroids whose orbit cross section can intersect the capture cross section of the Earth as a result of secular gravitational perturbations. This thesis provides a framework for understanding the origin, nature, and types of ECAs. The change in velocity requirements to achieve a two Earth radii deflection for long and short term warning scenarios are developed. Next, a method of developing hypothetical Earth colliding asteroid orbits is presented. The...

  5. Small asteroid fragments in earth-crossing orbits

    Science.gov (United States)

    Duha, J.; Afonso, G. B.

    2014-10-01

    The meteorite that fell in Chelyabinsk, Russia, naturally made many people think it could be a smaller companion of the Asteroid 2012 DA14, which passed close to Earth on that same day. Some asteroid specialists discarded this hypothesis for two main reasons: The meteorite was too far away from the asteroid, because the collision happened sixteen hours before the asteroid passed close to Earth. Moreover, it was not traveling, similarly to asteroid DA14, from south to north. However the possibility of the meteorite being a companion of the Asteroid 2012 DA14 cannot be completely discarded. The Asteroid 2012 DA14, with a diameter of 45 meters, is very small. It can be considered an asteroids fragment, which is usually accompanied by other smaller fragments, scattered in space, practically in the same orbit and possibly being separated from each other by long distances. Assuming that 2012 DA14 is not an isolated asteroid, but the biggest remaining fragment from a previous impact, we developed a model to study the dynamics of an asteroid fragment, similar to DA14, and its companions, the smaller fragments. This dynamically interesting encounter with planet Earth is addressed and the orbital changes that could explain the Chelyabinsk event are discussed. As a result we find that, there could be a collision of a meteorite before, during, or after the Asteroid 2012 DA14 passing by, the same way that happens with meteorite showers, which can last several days. Therefore, it would be very interesting to look for asteroid fragments also, close to the larger fragments, more easily found.

  6. The detectability of asteroids and comets before earth impact

    Energy Technology Data Exchange (ETDEWEB)

    Hills, J.

    1996-09-01

    In this final report of a 1-y LDRD project at LANL, requirements were investigated for detecting asteroids and comets in the final years before they impact Earth. Equipment and strategies were determined for detecting impacting asteroids and comets in all their permitted orbits. When this information is combined with possible mechanisms for diverting asteroids, it will determine the degree of readiness and minimum capability of deflection mechanisms required to prevent impact of these objects with Earth.

  7. International collaboration leads to new Aten asteroid discovery, 1984 QA

    Science.gov (United States)

    Helin, E. F.; Dunbar, R. S.; Barucci, M. A.

    1986-01-01

    A new earth-crossing asteroid of the Aten type (orbit smaller than earth's) was discovered on August 30, 1984 at Palomar. The asteroid, designated 1984 QA, is the fourth known member of the Aten type and the first discovered since 1978. The discovery of this object was the highlight of a collaboration between the JPL Asteroid Search Team and an ESA scientist, and demonstrates one aspect of an ongoing joint search effort with other Schmidt observers.

  8. NEOWISE Reactivation Mission Year One: Preliminary Asteroid Diameters and Albedos

    CERN Document Server

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

    2015-01-01

    We present preliminary diameters and albedos for 7,959 asteroids detected in the first year of the NEOWISE Reactivation mission. 201 are near-Earth asteroids (NEAs). 7,758 are Main Belt or Mars-crossing asteroids. 17% of these objects have not been previously characterized using WISE 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. Near Earth Asteroids with measurable Yarkovsky effect

    CERN Document Server

    Farnocchia, D; Vokrouhlicky, D; Milani, A; Spoto, F

    2012-01-01

    We seek evidence of the Yarkovsky effect among Near Earth Asteroids (NEAs) by measuring the Yarkovsky-related orbital drift from the orbital fit. To prevent the occurrence of unreliable detections we employ a high precision dynamical model, including the Newtonian attraction of 16 massive asteroids and the planetary relativistic terms, and a suitable astrometric data treatment. We find 21 NEAs whose orbital fits show a measurable orbital drift with a signal to noise ratio (SNR) greater than 3. The best determination is for asteroid (101955) 1999 RQ36, resulting in the recovery of one radar apparition and an orbit improvement by two orders of magnitude. In addition, we find 16 cases with a lower SNR that, despite being less reliable, are good candidates for becoming stronger detections in the future. In some cases it is possible to constrain physical quantities otherwise unknown by means of the detected orbital drift. Furthermore, the distribution of the detected orbital drifts shows an excess of retrograde ro...

  15. 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.

  16. Disintegrating Asteroid P/2013 R3

    CERN Document Server

    Jewitt, David; Li, Jing; Weaver, Harold; Mutchler, Max; Larson, Stephen

    2014-01-01

    Splitting of the nuclei of comets into multiple components has been frequently observed but, to date, no main-belt asteroid has been observed to break-up. Using the Hubble Space Telescope, we find that main-belt asteroid P/2013 R3 consists of 10 or more distinct components, the largest up to 200 m in radius (assumed geometric albedo of 0.05) each of which produces a coma and comet-like dust tail. A diffuse debris cloud with total mass roughly 2x10^8 kg further envelopes the entire system. The velocity dispersion among the components is about V = 0.2 to 0.5 m/s, is comparable to the gravitational escape speeds of the largest members, while their extrapolated plane-of-sky motions suggest break-up between February and September 2013. The broadband optical colors are those of a C-type asteroid. We find no spectral evidence for gaseous emission, placing model-dependent upper limits to the water production rate near 1 kg/s. Breakup may be due to a rotationally induced structural failure of the precursor body.

  17. Rotation and gravitational compaction in asteroids

    Science.gov (United States)

    Halling, R.

    A theoretical model of gravitational compaction during the formation of asteroids is developed on the basis of the planetesimal-accretion theory of Alfven and Arrhenius (1976) and applied to the observational data of Dermott and Murray (1982) on nonfamily main-belt C, S, and M asteroids of diameter 50 km or greater (assumed to be primordial objects). Three phases of accretion are defined: initial accretion of porous material at constant density until a critical radius and central pressure (of the order of 1 MPa) are attained, breakdown and compaction proceeding outward and resulting in a reduction of asteroid radius, and continued accretion with an increase in the volume friction in the compact state. A spin-frequency/diameter relation is derived by fitting this model to the data and found to give porous-state densities between 0.75 and 1.60 g/cu cm, compact-state densities 2.20-4.50 g/cu cm, critical radii 55-101 km, and postbreakdown radii 53-90 km.

  18. DISINTEGRATING ASTEROID P/2013 R3

    Energy Technology Data Exchange (ETDEWEB)

    Jewitt, David; 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); Weaver, Harold [The Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, 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 Boulevard, Tucson, AZ 85721-0092 (United States)

    2014-03-20

    Splitting of the nuclei of comets into multiple components has been frequently observed but, to date, no main-belt asteroid has been observed to break up. Using the Hubble Space Telescope, we find that main-belt asteroid P/2013 R3 consists of 10 or more distinct components, the largest up to 200 m in radius (assumed geometric albedo of 0.05) each of which produces a coma and comet-like dust tail. A diffuse debris cloud with total mass ∼2 × 10{sup 8} kg further envelopes the entire system. The velocity dispersion among the components, ΔV ∼ 0.2-0.5 m s{sup –1}, is comparable to the gravitational escape speeds of the largest members, while their extrapolated plane-of-sky motions suggest a break up between 2013 February and September. The broadband optical colors are those of a C-type asteroid. We find no spectral evidence for gaseous emission, placing model-dependent upper limits to the water production rate ≤1 kg s{sup –1}. Breakup may be due to a rotationally induced structural failure of the precursor body.

  19. 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.

  20. UBV photometry of asteroid 433 Eros

    Science.gov (United States)

    Millis, R. L.; Bowell, E.; Thompson, D. T.

    1976-01-01

    UBV observations of asteroid 433 Eros were conducted on 17 nights during the winter of 1974/75. The peak-to-peak amplitude of the lightcurve varied from about 0.3 mag to nearly 1.4 mag. The absolute V mag at maximum light, extrapolated to zero phase, is 10.85. Phase coefficients of 0.0233 mag/degree, 0.0009 mag/degree, and 0.0004 mag/degree were derived for V, B-V and U-B, respectively. The zero-phase color of Eros (B-V = 0.88, U-B = 0.50) is representative of an S (silicaceous) compositional type asteroid. The color does not vary with rotation. The photometric behavior of Eros can be modeled by a cylinder with rounded ends having an axial ratio of about 2.3:1. The asteroid is rotating about a short axis with the north pole at 15 deg ecliptic longitude and 9 deg ecliptic latitude.

  1. 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...

  2. HOW TO FIND METAL-RICH ASTEROIDS

    Energy Technology Data Exchange (ETDEWEB)

    Harris, Alan W.; Drube, Line, E-mail: alan.harris@dlr.de [German Aerospace Center (DLR) Institute of Planetary Research, Rutherfordstrasse 2, D-12489 Berlin (Germany)

    2014-04-10

    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.

  3. 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.

  4. 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.

  5. Studies of asteroids, comets, and Jupiter's outer satellites

    Science.gov (United States)

    Bowell, Edward

    1988-01-01

    The work comprises observational, theoretical, and computational research on asteroids, together with a smaller effort concerning the astrometry of comets and Jupiter's satellites JVI through JXIII. Two principal areas of research, centering on astrometry and photometry, are interrelated in their aim to study the overall structure of the asteroid belt and the physical and orbital properties of individual asteroids. About 2000 accurate photographic positions of asteroids and comets, including a number from the Lowell, Palomar, and Goethe-Link archival plate collections, the last of which was donated to us last winter by Indiana University were measured and published. Charge coupled device (CCD) astrometry of 36 faint targets was undertaken, including 4 comets; JVI, JVII, JVIII, JLX, JXI, and JXII; and 26 asteroids, most of which are Earth-approachers. A deep, bias-correctable asteroid survey (LUKAS), the aim of which is to determine the true spatial distribution of asteroids down to subkilometer diameters was started. A series of eight plates at the UK Schmidt telescope that contain images of asteroids as faint as V approximately 22 mag was obtained. Analysis of microdensitometric scans of two plates has shown that about 98 percent of the asteroid images could be identified completely automatically.

  6. 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.

  7. Detecting Extrasolar Asteroid Belts Through Their Microlensing Signatures

    CERN Document Server

    Lake, Ethan; Dong, Subo

    2016-01-01

    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 microlensing light curves across a wide region of belt parameter space and possess remarkably large lensing cross-sections. Sample light curves for a range of asteroid belt parameters are presented. In the near future, space-based microlensing surveys (e.g., WFIRST) may be able to discover extrasolar asteroid belts with masses of the order of $0.1 M_{\\oplus}$.

  8. Photometric geodesy of main-belt asteroids. III. Additional lightcurves

    International Nuclear Information System (INIS)

    A total of 107 complete or partial lightcurves are presented for 59 different asteroids over the 1982-1989 period. Unusual lightcurves with unequal minima and maxima at large amplitudes are preferentially seen for M-type asteroids. Some asteroids, such as 16 Psyche and 201 Penelope, exhibit lightcurves combining large amplitude with very unequal brightness for both maxima and both minima, even at small phase angles. An M-type asteroid is believed to consist of a metal core of a differentiated parent body that has had its rocky mantle completely removed by one or more large impacts. 39 refs

  9. Capturing asteroids into bound orbits around the earth: Massive early return on an asteroid terminal defense system

    Energy Technology Data Exchange (ETDEWEB)

    Hills, J.G.

    1992-02-06

    Nuclear explosives may be used to capture small asteroids (e.g., 20--50 meters in diameter) into bound orbits around the earth. The captured objects could be used for construction material for manned and unmanned activity in Earth orbit. Asteroids with small approach velocities, which are the ones most likely to have close approaches to the Earth, require the least energy for capture. They are particularly easy to capture if they pass within one Earth radius of the surface of the Earth. They could be intercepted with intercontinental missiles if the latter were retrofit with a more flexible guiding and homing capability. This asteroid capture-defense system could be implemented in a few years at low cost by using decommissioned ICMs. The economic value of even one captured asteroid is many times the initial investment. The asteroid capture system would be an essential part of the learning curve for dealing with larger asteroids that can hit the earth.

  10. 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

  11. Photometry of asteroids: Lightcurves of 24 asteroids obtained in 1993 2005

    Science.gov (United States)

    Chiorny, V. G.; Shevchenko, V. G.; Krugly, Yu. N.; Velichko, F. P.; Gaftonyuk, N. M.

    2007-05-01

    The results of 1993-2005 photometric observations for 24 main-belt asteroids: 24 Themis, 51 Nemausa, 89 Julia, 205 Martha, 225 Henrietta, 387 Aquitania, 423 Diotima, 505 Cava, 522 Helga, 543 Charlotte, 663 Gerlinde, 670 Ottegebe, 693 Zerbinetta, 694 Ekard, 713 Luscinia, 800 Kressmania, 1251 Hedera, 1369 Ostanina, 1427 Ruvuma, 1796 Riga, 2771 Polzunov, 4908 Ward, 6587 Brassens and 16541 1991 PW18 are presented. The rotation periods of nine of these asteroids have been determined for the first time and others have been improved.

  12. Asteroid Airbursts: Risk Assessment and Reduction

    Science.gov (United States)

    Boslough, M.

    2015-12-01

    Airbursts are events in which small (meters to tens-of-meters in diameter) asteroids deposit most of their energy in the atmosphere with a total energy greater than small nuclear explosions (>0.1 kilotons of TNT). The airburst risk is higher than previous assessments for two reasons. First, they are more frequent than previously thought. The Tunguska-class (~40 meters) population estimate has doubled, and Chelyabinsk-class (~20 meters) has increased by a factor of 2.6. Second, asteroid airbursts are significantly more damaging than previously assumed. In most cases, they more efficiently couple energy to the surface than nuclear explosions of the same yield. Past Near-Earth Object (NEO) risk assessments concluded that the largest asteroids (> 1 km) dominated the hazard. Large NEOs represent only a tiny fraction of the population but the potential for global catastrophe means that the contribution from low-probability, high-consequence events is large. Nearly 90% of these objects, none of which is on a collision course, have been catalogued. This has reduced their assessed near-term statistical risk by more than an order of magnitude because completion is highest for the largest and most dangerous. The relative risk from small objects would therefore be increasing even if their absolute assessed risk were not. Uncertainty in the number of small NEOs remains large and can only be reduced by expanded surveys. One strategy would be to count small NEOs making close passes in statistically significant numbers. For example, there are about 25 times as many objects of a given size that pass within the distance of geosynchronous orbit than collide with the earth, and 2000 times as many pass within a lunar distance (accounting for gravitational focusing). An asteroid the size of the Chelyabinsk impactor (~20 m) could potentially be observed within geosynchronous orbit every two years and within lunar orbit nearly once a week. A Tunguska-sized asteroid (~40 m) passes within a

  13. The software IDA for investigation of asteroid dynamics and its use for study of some asteroid motion (Abstract)

    Science.gov (United States)

    Galushina, T.; Bykova, L.; Letner, O.; Baturin, A.

    2015-08-01

    This work is devoted to description of the application suite IDA that is designed for investigation of dynamics and probability orbital evolution of asteroids. IDA allows to predict asteroid motion, to reveal close encounters, possible collisions and orbital resonance with planets, to estimate impact probability, to demonstrate asteroid and planets motion on a computer screen and to solve some additional problems. The features of the suite are multifunctionality, high efficiency and a convenient interface. The application suite IDA consists of following subsystems: subsystem "Assol" which allows to study orbital evolution of the nominal orbit and to demonstrate the asteroid and planets motion on a computer screen; subsystem "Observations" which intended to asteroid orbit fitting to positional observations and construction of initial probability domain with non-linear methods; subsystem "Distribution" which developed for the visualization of distribution of observations along an asteroid orbit; subsystem "Clones ensemble" which allows to construct an initial probability domain with the linear method; subsystem "Evolution" which designed for the study of the orbital evolution of an ensemble of asteroid clones; subsystem "Megno" which intended to estimate of predictability time of asteroid motion by means of average MEGNO parameter. The results of the motion investigation of the asteroid 2012 MF7 are given to demonstrate use of the application suite. This object has nonzero collision probability with the Earth in 2046.

  14. 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.

  15. Physical properties of asteroids in comet-like orbits in infrared asteroid survey catalogs

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yoonyoung; Ishiguro, Masateru [Department of Physics and Astronomy, Seoul National University, Gwanak, Seoul 151-742 (Korea, Republic of); Usui, Fumihiko [Department of Astronomy, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan)

    2014-07-10

    We investigated the population of asteroids in comet-like orbits using available asteroid size and albedo catalogs of data taken with the Infrared Astronomical Satellite, AKARI, and the Wide-field Infrared Survey Explorer on the basis of their orbital properties (i.e., the Tisserand parameter with respect to Jupiter, T{sub J}, and the aphelion distance, Q). We found that (1) there are 123 asteroids in comet-like orbits by our criteria (i.e., Q > 4.5 AU and T{sub J} < 3), (2) 80% of them have low albedo, p{sub v} < 0.1, consistent with comet nuclei, (3) the low-albedo objects among them have a size distribution shallower than that of active comet nuclei, that is, the power index of the cumulative size distribution is around 1.1, and (4) unexpectedly, a considerable number (i.e., 25 by our criteria) of asteroids in comet-like orbits have high albedo, p{sub v} > 0.1. We noticed that such high-albedo objects mostly consist of small (D < 3 km) bodies distributed in near-Earth space (with perihelion distance of q < 1.3 AU). We suggest that such high-albedo, small objects were susceptible to the Yarkovsky effect and drifted into comet-like orbits via chaotic resonances with planets.

  16. 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 Space Administration. ACTION: Notice of Public Conference to examine ideas in response to the recent RFI... posted at http://www.nasa.gov/content/asteroid-initiative-idea-synthesis-workshop prior to the event....

  17. Nature of the Kirkwood gaps in the asteroid belt

    Energy Technology Data Exchange (ETDEWEB)

    Dermott, S.F.; Murray, C.D. (Cornell Univ., Ithaca, NY (USA). Lab. for Planetary Studies)

    1983-01-20

    The distributions of orbital eccentricities and inclinations near the Jovian resonances in the asteroid belt show that the observed Kirkwood gaps in the distribution of the semimajor axes were formed after the asteroids had dispersed from the near-coplanar disk in which they accreted.

  18. 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

  19. 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.

  20. 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.

  1. 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.

  2. 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

  3. Implications of NEAR results for asteroid structure

    Science.gov (United States)

    Cheng, A.

    The NEAR Shoemaker spacecraft orbited the near-Earth asteroid 433 Eros from February, 2000 to February, 2001, finally landing on the asteroid and returning additional data from the surface. The NEAR Multispectral Imager, Laser Rangefinder, and Radio Science investigations obtained extensive observations pertinent to structure and morphology. These investigations revealed Eros to be a deeply fractured but largely intact body. The NEAR Infrared Spectrometer, X-ray Spectrometer and Gamma Ray Spectrometer also mapped surface compositions and did not find any evidence of compositional heterogeneity. Evidence from NEAR pertaining to the structure of Eros includes the following, reported by the NEAR team. Eros's average density of 2.67 gm/cc is less than the average bulk density of ordinary chondrites, indicating that bulk Eros is significantly porous and/or fractured. The interior of Eros is nearly uniform in density, as inferred from its gravity field, which is similar to that which would be expected from a uniform density object of the same shape. There is a small center of mass offset from the center of figure which may be consistent with an underdense regolith layer of up to 100 m depth. Surface morphology indicates a regolith up to tens of meters thick in places, inferred from the dearth of small craters (blocks and boulders in varying states of burial, and evidence for burial of small craters and for mass wasting. Craters on Eros are typically shallower than craters of the same diameter on the Moon. Tectonic features are found on Eros, as are structurally controlled craters. Aligned linear structures are common, and some of these are coherent on global scales. These results are compared to those reported by the NEAR team from asteroid 253 Mathilde. In both asteroids, giant craters are found in close proximity to one another. MathildeSs porosity is greater than that of Eros; MathildeSs average density is 1.3 gm/cc. This low density suggests a rubble pile structure

  4. 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.

  5. 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.

  6. The Strength of Regolith and Rubble Pile Asteroids

    CERN Document Server

    Sánchez, Paul

    2013-01-01

    We explore the hypothesis that, due to small van der Waals forces between regolith grains, the strength of small rubble pile asteroids is constant. This creates a scale dependence, with relative strength increasing as size decreases. This counters classical theory that rubble pile asteroids should behave as scale-independent cohesionless collections of rocks. We explore a simple model for asteroid strength that is based on these weak forces, validate it through granular mechanics simulations and comparisons with properties of lunar regolith, and then show its implications and ability to explain and predict observed properties of small asteroids in the NEA and Main Belt populations. A conclusion is that the population of rapidly rotating asteroids consists of both distributions of smaller grains (i.e., rubble piles) and of monolithic boulders whose surfaces may still retain a size distribution of finer grains, potentially of size up to centimeters.

  7. 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).

  8. 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...

  9. 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.

  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. 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.

  12. 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.

  13. Photometry of Fourteen Main Belt Asteroids

    Directory of Open Access Journals (Sweden)

    R. Gil Hutton

    2003-01-01

    Full Text Available Se presentan resultados de fotometría CCD para 14 asteroides del cinturón principal obtenida entre 1996 y 2000. Para la mayoría de los objetos observados se encontraron las curvas de luz compuestas en los filtros V o R y los períodos de rotación sinódicos. Para 11 de los objetos estudiados no existía una determinación previa de su período de rotación

  14. 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.

  15. An optimal Mars Trojan asteroid search strategy

    OpenAIRE

    Todd, M; Tanga, P.; Coward, D. M.; Zadnik, M. G.

    2012-01-01

    Trojan asteroids are minor planets that share the orbit of a planet about the Sun and librate around the L4 or L5 Lagrangian points of stability. Although only three Mars Trojans have been discovered, models suggest that at least ten times this number should exist with diameters >= 1 km. We derive a model that constrains optimal sky search areas and present a strategy for the most efficient use of telescope survey time that maximizes the probability of detecting Mars Trojans. We show that the...

  16. Super-catastrophic disruption of asteroids at small perihelion distances.

    Science.gov (United States)

    Granvik, Mikael; Morbidelli, Alessandro; Jedicke, Robert; Bolin, Bryce; Bottke, William F; Beshore, Edward; Vokrouhlický, David; Delbò, Marco; Michel, Patrick

    2016-02-18

    Most near-Earth objects came from the asteroid belt and drifted via non-gravitational thermal forces into resonant escape routes that, in turn, pushed them onto planet-crossing orbits. Models predict that numerous asteroids should be found on orbits that closely approach the Sun, but few have been seen. In addition, even though the near-Earth-object population in general is an even mix of low-albedo (less than ten per cent of incident radiation is reflected) and high-albedo (more than ten per cent of incident radiation is reflected) asteroids, the characterized asteroids near the Sun typically have high albedos. Here we report a quantitative comparison of actual asteroid detections and a near-Earth-object model (which accounts for observational selection effects). We conclude that the deficit of low-albedo objects near the Sun arises from the super-catastrophic breakup (that is, almost complete disintegration) of a substantial fraction of asteroids when they achieve perihelion distances of a few tens of solar radii. The distance at which destruction occurs is greater for smaller asteroids, and their temperatures during perihelion passages are too low for evaporation to explain their disappearance. Although both bright and dark (high- and low-albedo) asteroids eventually break up, we find that low-albedo asteroids are more likely to be destroyed farther from the Sun, which explains the apparent excess of high-albedo near-Earth objects and suggests that low-albedo asteroids break up more easily as a result of thermal effects. PMID:26887492

  17. Near-Earth asteroids: Metals occurrence, extraction, and fabrication

    Science.gov (United States)

    Westfall, Richard

    1991-01-01

    Near-earth asteroids occur in three principle types of orbits: Amor, Apollo, and Aten. Amor asteroids make relatively close (within 0.3 AU) approaches to the earth's orbit, but do not actually overlap it. Apollo asteroids spend most of their time outside the earth's orbital path, but at some point of close approach to the sun, they cross the orbit of the earth. Aten asteroids are those whose orbits remain inside the earth's path for the majority of their time, with semi-major axes less than 0.1 AU. Near-earth orbit asteroids include: stones, stony-irons, irons, carbonaceous, and super-carbonaceous. Metals within these asteroids include: iron, nickel, cobalt, the platinum group, aluminum, titanium, and others. Focus is on the extraction of ferrous and platinum group metals from the stony-iron asteroids, and the iron asteroids. Extraction of the metal fraction can be accomplished through the use of tunnel-boring-machines (TBM) in the case of the stony-irons. The metals within the story-iron asteroids occur as dispersed granules, which can be separated from the stony fraction through magnetic and gaseous digestion separation techniques. The metal asteroids are processes by drilling and gaseous digestion or by gaseous digestion alone. Manufacturing of structures, housings, framing networks, pressure vessels, mirrors, and other products is accomplished through the chemical vapor deposition (CVD) of metal coating on advanced composites and on the inside of contour-defining inflatables (CDI). Metal coatings on advanced composites provide: resistance to degradation in the hostile environments of space; superior optical properties; superior heat dissipation; service as wear coatings; and service as evidential coatings. Metal coatings on the inside of CDI produce metal load-bearing products. Fibers such as graphite, kevlar, glass, ceramic, metal, etc., can be incorporated in the metal coatings on the inside of CDI producing metal matrix products which exhibit high strength

  18. Asteroid Lightcurve Analysis at Isaac Aznar Observatory Aras De Los Olmos, Valencia, Spain

    Science.gov (United States)

    Macias, Amadeo Aznar

    2015-01-01

    The Isaac Aznar Observatory conducts astrometric and photometric studies of asteroids. This paper contains the photometric results of four asteroids obtained from 2014 April to August. These asteroids were selected from the Collaborative Asteroid Lightcurve Link (CALL) web site: 1088 Mitaka, 2956 Yeomans, 3894 Williamcooke, and (4555) 1974QL.

  19. 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.

  20. The Orbit of Asteroid 1994 PC1

    CERN Document Server

    Balkoski, Sophia Jane; Wang, Milly KeQi

    2011-01-01

    Near-Earth Asteroids can be hazardous to the Earth, due to their orbital characteristics and proximity to inner Solar System planets. Using three sets of CCD images collected in June and July 2011, the orbital elements of asteroid 1994 PC1 were determined at solar opposition. The body's specific right ascension and declination were calculated through least squares plate reduction (taking parallax into account) and compared to those of the Jet Propulsion Laboratory. These data were then used to find 1994 PC1's orbital elements, as well as any statistical uncertainty. This research points to an eccentricity of 0.3272 (+0.00009 or -0.0005), a semi major axis of 1.3401 AU (+0.0001 AU or -0.0004 AU), an inclination angle of 33.30^{\\circ} (+0.05^{\\circ} or -0.01^{\\circ}), a longitude of the ascending node of 118.01^{\\circ} (+0.09^{\\circ} or -0.02^{\\circ}), an argument of perihelion of 47.14^{\\circ} (+0.005^{\\circ} or -0.08^{\\circ}), and a time of last perihelion of JD 2455642.88 (+0.007 or -0.03).

  1. Spectral Similarity of Unbound Asteroid Pairs

    CERN Document Server

    Wolters, Stephen D; Christou, Apostolis; Duddy, Samuel R; Lowry, Stephen C

    2014-01-01

    Infrared spectroscopy between 0.8 and 2.5 microns has been obtained for both components of three unbound asteroid pairs, using the NASA-IRTF with the SpeX instrument. Pair primary (2110) Moore-Sitterly is classified as an S-type following the Bus-DeMeo taxonomy; the classification for secondary (44612) 1999 RP27 is ambiguous: S/Sq/Q/K/L-type. Primary (10484) Hecht and secondary (44645) 1999 RC118 are classified as V-types. IR spectra for Moore-Sitterly and Hecht are each linked with available visual photometry. The classifications for primary (88604) 2001 QH293 and (60546) 2000 EE85 are ambiguous: S/Sq/Q/K/L-type. Subtle spectral differences between them suggest the primary may have more weathered material on its surface. Dynamical integrations have constrained the ages of formation: 2110-44612 > 782 kyr; 10484-44645 = 348 (+823,-225) kyr; 88604-60546 = 925 (+842,-754) kyr. The spectral similarity of seven complete pairs is ranked in comparison with nearby background asteroids. Two pairs, 17198-229056 and 192...

  2. 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.

  3. 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.

  4. Modeling Asteroid Spin-up with Cohesion

    Science.gov (United States)

    Walsh, Kevin J.; Richardson, D. C.; Michel, P.

    2008-09-01

    Recent work has shown that the gradual spin-up of cohesionless gravitational aggregates produces a wide range of outcomes depending on the specific configuration of the body, such as particle size distribution. One important outcome is the creation of binary asteroids, which requires bodies that can maintain spherical/oblate shapes as the body is spun to rapid rotation (Walsh et al., 2008, Nature, 454, 188-191). Our recent work includes a similar model which also models cohesion within the gravitational aggregate by way of a spring-like restoring force between neighboring particles that vanishes under high strain. We will present early results of gradual spin-up tests on gravitational aggregates covering a large range of starting conditions including the initial body shape and size, as well as varying configurations for the cohesion properties. These results will be compared to previous spin-up work as well as analytical theory. KJW and PM had the support of the French Programme National de Planétologie and the ACT Team of ESA and Ariadna Study 07/4111"Asteroid Rotational Fragmentation". KJW is also supported by the Henri Poincaré fellowship at the Observatoire de la Côte d'Azur, Nice, France, and Rotary International -- District 1730. DCR acknowledges support from the National Science Foundation under grant AST0708110 and the National Aeronautics and Space Administration under Grant No. NNX08AM39G.

  5. 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...

  6. Secular variation of a metallic asteroid dynamo

    Science.gov (United States)

    Bryson, J. F. J.; Harrison, R. J.; Neufeld, J. A.; Nimmo, F.; Herrero-Albillos, J.; Kronast, F.; Weiss, B. P.

    2015-12-01

    The mechanisms by which inward core solidification may drive dynamo activity, and the properties of any fields that may result from this process, are highly uncertain. The fast cooling rates of the IVA iron meteorites suggest that their parent core had its silicate mantle removed by planetary collisions during the early solar system. Due to the resulting rapid radiative surface cooling, the IVA parent core solidified from the top-down, permitting a cold metallic crust that feasibly experienced fields generated by the hot interior liquid as it inwardly solidified. The IVA meteorites therefore potentially contain unique paleomagnetic information regarding top-down solidification. Through x-ray microscopy of the cloudy zone in the Steinbach and Chinautla meteorites and traditional paleomagnetic measurements on silicates extracted from the Steinbach, Bishop Canyon and São João Nepomuceno meteorites, we argue that the IVA parent core generated an intense (>100 μT) and secularly varying (time-scale Mercury, Ganymede, many asteroids). Combining this observation with that of efficient solidification-driven dynamos during bottom-up asteroid core solidification, it is likely that magnetic activity was widespread in the early solar system.

  7. JOVIAN EARLY BOMBARDMENT: PLANETESIMAL EROSION IN THE INNER ASTEROID BELT

    Energy Technology Data Exchange (ETDEWEB)

    Turrini, D.; Coradini, A.; Magni, G., E-mail: diego.turrini@ifsi-roma.inaf.it [Istituto di Astrofisica e Planetologia Spaziali, INAF-IAPS, Via Fosso del Cavaliere 100, 00133, Rome (Italy)

    2012-05-01

    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 (SFDs). 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 depends on the SFD of the primordial planetesimals. If the asteroid belt was dominated by planetesimals less than 100 km in diameter, the primordial bombardment would have caused the erosion of bodies smaller than 200 km in diameter. If the asteroid belt was instead dominated by larger planetesimals, the bombardment would have resulted in the destruction of bodies as big as 500 km.

  8. Asteroid models from combined sparse and dense photometric data

    Science.gov (United States)

    Durech, J.; Kaasalainen, M.; Warner, B. D.; Fauerbach, M.; Marks, S. A.; Fauvaud, S.; Fauvaud, M.; Vugnon, J.-M.; Pilcher, F.; Bernasconi, L.; Behrend, R.

    2009-01-01

    Aims: Shape and spin state are basic physical characteristics of an asteroid. They can be derived from disc-integrated photometry by the lightcurve inversion method. Increasing the number of asteroids with known basic physical properties is necessary to better understand the nature of individual objects as well as for studies of the whole asteroid population. Methods: We use the lightcurve inversion method to obtain rotation parameters and coarse shape models of selected asteroids. We combine sparse photometric data from the US Naval Observatory with ordinary lightcurves from the Uppsala Asteroid Photometric Catalogue and the Palmer Divide Observatory archive, and show that such combined data sets are in many cases sufficient to derive a model even if neither sparse photometry nor lightcurves can be used alone. Our approach is tested on multiple-apparition lightcurve inversion models and we show that the method produces consistent results. Results: We present new shape models and spin parameters for 24 asteroids. The shape models are only coarse but describe the global shape characteristics well. The typical error in the pole direction is ~10-20°. For a further 18 asteroids, inversion led to a unique determination of the rotation period but the pole direction was not well constrained. In these cases we give only an estimate of the ecliptic latitude of the pole.

  9. Statistical ranging of asteroid orbits: efficient MCMC and importance samplers

    Science.gov (United States)

    Virtanen, Jenni; Fedorets, Grigori; Granvik, Mikael; Oszkiewicz, Dagmara Anna; Muinonen, Karri

    2015-08-01

    We address the asteroid initial orbit computation problem by comparing various versions of the statistical ranging method (Virtanen et al. 2001, Muinonen et al. 2001) developed for exiguous observational data. In particular, the performance of the Markov-chain Monte Carlo (MCMC) ranging (Oszkiewicz et al. 2009) and the importance-sampler ranging methods, including the most recently developed random-walk ranging (Muinonen et al. 2015) are compared. We demonstrate the capabilities of the methods for various classes of asteroids, including near-Earth and main-belt asteroids, as well as transneptunian objects. We also study the performance of our statistical inverse methods as a function of increasing observational time interval, i.e., during the so-called phase transition. We also envision the application of the methods for space-debris orbits.Muinonen, K., Virtanen, J., Bowell, E., 2001. Collision probability for Earth-crossing asteroids using orbital ranging. Celestial Mechanics and Dynamical Astronomy 81, 93-101.Muinonen K., et al. 2015. Asteroid orbits from Gaia astrometry with random-walk statistical ranging, Planetary and Space Science, in preparation.Oszkiewicz, D., Muinonen, K., Virtanen, J., Granvik, M., 2009. Asteroid orbital ranging using Markov-chain Monte Carlo. Meteoritics and Planetary Science 44, 12, 1897-1904.Virtanen, J., Muinonen, K., Bowell, E., 2001. Statistical ranging of asteroid orbits. Icarus 154, 412-431.

  10. On the dynamical dispersal of primordial asteroid families

    Science.gov (United States)

    Ivo de Oliveira Brasil, Pedro; Roig, Fernando; Nesvorný, David; Carruba, Valerio; Aljbaae, Safwan; Espinoza Hauman, Mariela

    2015-11-01

    Many asteroid families are identified and well characterized all over the main belt asteroid. Interestingly, however, none of them are older than ~4 Gyr. Many mechanisms have been proposed to disperse such old primordial asteroid families that presumably have existed, but none have really worked. Here we present a plausible mechanism for dispersing primordial asteroid families that is based on the 5-planet instability model known as jumping Jupiter. Using two different evolutions for the jumping-Jupiter model, we have numerically integrated orbits of eight primordial families. Our results show that the most important effect on the asteroid families' eccentricity and inclination dispersal is that of the secular resonances, in some cases associated with the mean motion resonances. As for the semimajoraxes spreading we find that the principal effect is that of close encounters with the fifth giant planet whose orbit briefly overlaps with (part of) the main belt. Therefore, the existence of a fifth giant planet with the mass comparable with that of Uranus' or Neptune's could contribute in important ways to dispersal of the primordial asteroid families. To have that effect, the interloper planet should penetrate and considerably interact with the asteroids during the instability phase.

  11. Mission Designs for Demonstrating Gravity Tractor Asteroid Deflection

    Science.gov (United States)

    Busch, M.; Faber, N.; Eggl, S.; Morrison, D.; Clark, A.; Frost, C.; Jaroux, B. A.; Khetawat, V.

    2015-12-01

    Gravity tractor asteroid deflection relies on the gravitational attraction between the target and a nearby spacecraft; using low-thrust propulsion to change the target's trajectory slowly but continuously. Our team, based at the NASA Ames Mission Design Center, prepared designs for a Gravity Tractor Demonstration Mission (GTDM) for the European Commission's NEOShield initiative. We found five asteroids with well-known orbits and opportunities for efficient stand-alone demonstrations in the 2020s. We selected one object, 2000 FJ10, for a detailed design analysis. Our GTDM design has a 4 kW solar-electric propulsion system and launch mass of 1150 kg. For a nominal asteroid mass of 3 x 109 kg and diameter 150 m, and a hovering altitude 125 m above the asteroid's surface, GTDM would change FJ10's semi-major axis by 10 km over 2 years. To measure the deflection clearly and to permit safe hovering by the spacecraft, several months of survey and characterization are required prior to the active tractoring phase of the mission. Accurate tracking is also required after the tractoring phase, to ensure that the asteroid has indeed been deflected as intended. The GTDM design includes both spacecraft and Earth-based observations of FJ10 to verify the deflection. The estimated cost of GTDM is $280 million. Trajectory analysis for GTDM confirmed that the outcome of a deflection of any asteroid depends on when that deflection is performed. Compared to kinetic impactor deflection, the gradual deflection from a gravity tractor produces comparable results for a given total momentum transfer. However, a gravity tractor can have greater flexibility in the direction in which the target asteroid can be deflected. Asteroid deflection scenarios must be modeled carefully on a case-to-case basis. We will review implications of the results of the GTDM study to other proposed gravity tractor demonstrations, such as that included in NASA's Asteroid Redirect Mission.

  12. Meteoroid Impact Ejecta Detection by Nanosatellites for Asteroid Surface Characterization

    Science.gov (United States)

    Lee, N.; Close, S.; Goel, A.

    2015-12-01

    Asteroids are constantly bombarded by much smaller meteoroids at extremely high speeds, which results in erosion of the material on the asteroid surface. Some of this material is vaporized and ionized, forming a plasma that is ejected into the environment around the asteroid where it can be detected by a constellation of closely orbiting nanosatellites. We present a concept to leverage this natural phenomenon and to analyze this excavated material using low-power plasma sensors on nanosatellites in order to determine the composition of the asteroid surface. This concept would enable a constellation of nanosatellites to provide useful data complementing existing techniques such as spectroscopy, which require larger and more power-hungry sensors. Possible mission architectures include precursor exploratory missions using nanosatellites to survey and identify asteroid candidates worthy of further study by a large spacecraft, or simultaneous exploration by a nanosatellite constellation with a larger parent spacecraft to decrease the time required to cover the entire asteroid surface. The use of meteoroid impact plasma to analyze the surface composition of asteroids will not only produce measurements that have not been previously obtained, including the molecular composition of the surface, but will also yield a better measurement of the meteoroid flux in the vicinity of the asteroid. Current meteoroid models are poorly constrained beyond the orbit of Mars, due to scarcity of data. If this technology is used to survey asteroids in the main belt, it will offer a dramatic increase in the availability of meteoroid flux measurements in deep space, identifying previously unknown meteoroid streams and providing additional data to support models of solar system dust dynamics.

  13. Dust productivity and impact collision of the asteroid (596) Scheila

    Science.gov (United States)

    Neslusan, L.; Ivanova, O.; Husarik, M.; Svoren, J.; Krisandova, Z. Seman

    2016-06-01

    Photometric observations of asteroid (596) Scheila were obtained during and after its 2010 outburst. The estimated radius of the body (spherical approximation of the asteroidal body) was 51.2±3.0 km and 50.6±3.0 km for different methods. The ejected dust mass from the asteroid ranged from 2.5 ×107 to 3.4 ×107 kg for different methods. An impact mechanism for triggering Scheila's activity is discussed. A few days before the impact, Scheila passed through the corridors of two potential cometary streams.

  14. 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.

  15. 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.

  16. Overview of NASA’s Asteroid Redirect Mission Concept

    Science.gov (United States)

    Chodas, Paul W.; Muirhead, Brian; Gates, Michele

    2015-08-01

    The Asteroid Redirect Mission (ARM) is a proposed mission to develop an advanced Solar Electric Propulsion spacecraft, and test it by capturing a large mass of asteroidal material in interplanetary space and returning it to a Lunar Distant Retrograde Orbit where it can be explored by a crew of astronauts visiting in an Orion spacecraft. This paper provides a summary of the ARM concept development, including the mission architecture, flight system concepts, the advanced solar electric propulsion system, and the asteroid capture system concepts. Extensibility to future human exploration of the Solar System will also be discussed.

  17. New study reveals twice as many asteroids as previously believed

    Science.gov (United States)

    2002-05-01

    The ISO satellite Credits: ESA ISO An artist's impression of the ISO spacecraft. The ISO Deep Asteroid Search indicates that there are between 1.1 million and 1.9 million 'space rocks' larger than 1 kilometre in diameter in the so-called 'main asteroid belt', about twice as many as previously believed. However, astronomers think it is premature to revise current assessments of the risk of the Earth being hit by an asteroid. Despite being in our own Solar System, asteroids can be more difficult to study than very distant galaxies. With sizes of up to one thousand kilometres in diameter, the brightness of these rocky objects may vary considerably in just a few minutes. They move very quickly with respect to the stars - they have been dubbed 'vermin of the sky' because they often appear as trails on long exposure images. This elusiveness explains why their actual number and size distribution remains uncertain. Most of the almost 40,000 asteroids catalogued so far (1) orbit the Sun forming the 'main asteroid belt', between Mars and Jupiter, too far to pose any threat to Earth. However, space-watchers do keep a closer eye on another category of asteroids, the 'Near Earth Asteroids' or 'NEAs', which are those whose orbits cross, or are likely to cross, that of our planet. The ISO Deep Asteroid Search (IDAS), the first systematic search for these objects performed in infrared light, focused on main belt asteroids. Because it is impossible to simply point the telescope at the whole main belt and count, astronomers choose selected regions of the belt and then use a theoretical model to extrapolate the data to the whole belt. Edward Tedesco (TerraSystems, Inc., New Hampshire, United States) and François-Xavier Desert (Observatoire de Grenoble, France) observed their main belt selected areas in 1996 and 1997 with ESA's ISO. They found that in the middle region of the belt the density of asteroids was 160 asteroids larger than 1 kilometre per square degree - an area of the

  18. Physical properties of asteroid 433 Eros

    Science.gov (United States)

    Zellner, B.

    1976-01-01

    Newly available photometric, polarimetric, spectroscopic, thermal-radiometric, radar, and occultation results are synthesized in order to derive a coherent model for Eros. The geometric albedo is 0.19 plus or minus 0.01 at the visual wavelength, and the overall dimensions are approximately 13 by 15 by 36 km. The rotation is about the short axis, in the direct sense, with a sidereal period of 5 hr 16 min 13.4 sec. The pole of rotation lies within a few degrees of ecliptic coordinates 16 deg longitude and beta = +11 deg latitude. Eros is uniformly coated with a particulate surface layer several millimeters thick. It has an iron-bearing silicate composition, similar to that of a minority of main-belt asteroids, and probably identifiable with H-type ordinary chondrites.

  19. 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...

  20. Efficient early global relaxation of asteroid Vesta

    Science.gov (United States)

    Fu, Roger R.; Hager, Bradford H.; Ermakov, Anton I.; Zuber, Maria T.

    2014-09-01

    The asteroid Vesta is a differentiated planetesimal from the accretion phase of Solar System formation. Although its present-day shape is dominated by a non-hydrostatic fossil equatorial bulge and two large, mostly unrelaxed impact basins, Vesta may have been able to approach hydrostatic equilibrium during a brief early period of intense interior heating. We use a finite element viscoplastic flow model coupled to a 1D conductive cooling model to calculate the expected rate of relaxation throughout Vesta’s early history. We find that, given sufficient non-hydrostaticity, the early elastic lithosphere of Vesta experienced extensive brittle failure due to self-gravity, thereby allowing relaxation to a more hydrostatic figure. Soon after its accretion, Vesta reached a closely hydrostatic figure with scaled, is similar to the maximum disequilibrium of the hydrostatic asteroid Ceres. Vesta was able to support the modern observed amplitude of non-hydrostatic topography only >40-200 My after formation, depending on the assumed depth of megaregolith. The Veneneia and Rheasilvia giant impacts, which generated most non-hydrostatic topography, must have therefore occurred >40-200 My after formation. Based on crater retention ages, topography, and relation to known impact generated features, we identify a large region in the northern hemisphere that likely represents relic hydrostatic terrain from early Vesta. The long-wavelength figure of this terrain suggests that, before the two late giant impacts, Vesta had a rotation period of 5.02 h (6.3% faster than present) while its spin axis was offset by 3.0 ° from that of the present. The evolution of Vesta’s figure shows that the hydrostaticity of small bodies depends strongly on its age and specific impact history and that a single body may embody both hydrostatic and non-hydrostatic terrains and epochs.

  1. 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.

  2. 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

  3. Business analysis: The commercial mission of the International Asteroid Mission

    Science.gov (United States)

    The mission of the International Asteroid Mission (IAM) is providing asteroidal resources to support activities in space. The short term goal is to initiate IAM by mining a near-Earth, hydrous carbonaceous chondrite asteroid to service the nearer-term market of providing cryogenic rocket fuel in low lunar orbit (LLO). The IAM will develop and contract for the building of the transportation vehicles and equipment necessary for this undertaking. The long-term goal is to expand operations by exploiting asteroids in other manners, as these options become commercially viable. The primary business issues are what revenue can be generated from the baseline mission, how much will the mission cost, and how funding for this mission can be raised. These issues are addressed.

  4. 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...

  5. 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 ????.

  6. 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.

  7. 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...

  8. Sizes, Shapes, and Satellites of Asteroids from Occultations

    Science.gov (United States)

    Dunham, David W.; Herald, David; Preston, Steve; Timerson, Brad; Maley, Paul; Frappa, Eric; Hayamizu, Tsutomu; Talbot, John; Poro, Atila

    2016-01-01

    For 40 years, the sizes and shapes of many dozens of asteroids have been determined from observations of asteroidal occultations, and over a thousand high-precision positions of the asteroids relative to stars have been measured. Some of the first evidence for satellites of asteroids was obtained from the early efforts; now, the orbits and sizes of some satellites discovered by other means have been refined from occultation observations. Also, several close binary stars have been discovered, and the angular diameters of some stars have been measured from analysis of these observations. The International Occultation Timing Association (IOTA) coordinates this activity worldwide, from predicting and publicizing the events, to accurately timing the occultations from as many stations as possible, and publishing and archiving the observations.

  9. Collisional origin of asteroid families: effects of the target's gravity

    International Nuclear Information System (INIS)

    The outcomes of asteroidal catastrophic collisions are strongly affected by the target asteroid's gravity, since only the fragments escaping with initial velocities higher than the target's escape velocity are not reaccumulated into 'rubble pile' remnants. This idea can be compared with the observational evidence on the properties of family asteroids in several ways: (1) the shape and spin period of the 'reaccumulated' family asteroids will roughly fit the relationships valid for self-gravitating fluid bodies; (2) the relative velocities of the few escaping fragments arising from a breakup event marginally overcoming self-gravity will often have an anisotropic distribution, affecting the final distribution of orbital elements; (3) the amount of mass which in a given family escaped to 'infinity' will be correlated with the target's size, since only for objects larger than approx. 100 km self-gravity plays an important role. These predictions are discussed and compared with the available data. (Auth.)

  10. 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...

  11. 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.

  12. 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...

  13. 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.

  14. Low-energy capture of asteroids onto KAM tori

    CERN Document Server

    Verrier, Patricia E

    2015-01-01

    We present a new method for engineering the artificial capture of asteroids. Based on theories of the chaos-assisted capture of natural satellites of the giant planets, we show how an unbound asteroid that passes close to a regular region of phase space can be easily moved onto the nearby KAM tori and essentially permanently captured with the Earth's Hill sphere without closing the zero velocity curves. The method has the advantages of a relatively low delta-v requirement and no need for control strategies. An illustration of the method is given for an example asteroid trajectory, demonstrating that it is a viable strategy for the final capture stage of asteroids in the Earth's neighbourhood.

  15. 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.

  16. 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".

  17. 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

  18. 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

  19. Asteroid detection at millimetric wavelengths with the Planck survey

    OpenAIRE

    G. Cremonese; Marzari, F.; Burigana, C.; Maris, M.

    2002-01-01

    The Planck mission, originally devised for cosmological studies, offers the opportunity to observe Solar System objects at millimetric and submillimetric wavelengths. We concentrate in this paper on the asteroids of the Main Belt. We intend to estimate the number of asteroids that can can be detected during the mission and to evaluate the strength of their signal. We have rescaled the instrument sensitivities, calculated by the LFI and HFI teams for sources fixed in the sky, introducing some ...

  20. 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.

  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. 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.

  3. 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.

  4. 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...

  5. Internal Stresses For Realistic Asteroid Shapes: The Case Of Kleopatra

    Science.gov (United States)

    Hirabayashi, Masatoshi; Scheeres, D. J.

    2012-10-01

    We will present updated results for the averaged-normal stress and stress state within the asteroid Kleopatra. In this study we introduce a new method for computing the mutual gravity attraction of two generalized bodies in contact, which is applicable for computing the generalized stress field at any point within an asteroid. This methodology is applied to the asteroid Kleopatra, although computations for other asteroids will also be presented at the conference. Our method fills the asteroid shape with small equal-sized parallelepipeds and computes the higher order mutual gravity for each cube-pair. Since the gravitational attractions for pairs close to each other cannot be accurately modeled by a point mass assumption, we control the order of the gravity attraction computation by the relative distance. A validation test using the shape of an ellipsoid gives good agreement with the results of Holsapple (2001). We base our analysis on the radar-derived Kleopatra shape model (Ostro et al., 2009) with the updated total size and density from the (Deschamps et al., 2011) observations. Specifically we use a Kleopatra spin period of 5.38 hours and density of 3.2 g/cm3. The current results show that the asteroid is very close to being in a tensile state across its “neck” region and clearly has a localized stress concentration in this region. We will present results on the internal yield criterion and what limits can be inferred from this information.

  6. Rotation and photometric properties of E-type asteroids

    Science.gov (United States)

    Shevchenko, V. G.; Krugly, Yu. N.; Chiorny, V. G.; Belskaya, I. N.; Gaftonyuk, N. M.

    2003-08-01

    The results of photometric observations of seven E-type asteroids 64 Angelina, 214 Aschera, 1025 Riema, 1103 Sequoia, 1251 Hedera, 2035 Stearns, and 2248 Dwornik are presented. New rotation periods have been determined for asteroids 1025 Riema (6.557±0.001 h) , 1251 Hedera (15.015±0.010 h) , 2035 Stearns (85.0±0.1 h), and 2048 Dwornik (3.664±0.001 h) . Two new poles have been estimated for 214 Aschera (274±8°; 64±4°) and 1025 Riema (141±10°, 11±6°) and pole has been redefined for 64 Angelina (138±10°, 31±5°). Using all available data on rotation periods, the spin rates of E-type asteroids have been analyzed. The distribution of the spin rates has maximum corresponding to the period of about 6.2 h. The shapes of E-asteroids are more elongated than the shapes of small-size S-asteroids. The average values of color indexes, albedo and G parameter for E-type asteroids have also been determined.

  7. 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.

  8. 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.

  9. 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).

  10. 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.

  11. 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

  12. The Rosetta Fly-by at Asteroid (2867) Steins

    Science.gov (United States)

    Schulz, R.; Accomazzo, A.; Küppers, M.; Schwehm, G.; Wirth, K.

    2009-05-01

    The International Rosetta Mission is one of ESA's Planetary Cornerstone Missions on its way to rendezvous with comet 67P/Churyumov-Gerasimenko. On route to the comet Rosetta has encountered its first asteroid target, main belt asteroid (2867) Steins. Closest approach occurred on 5 September 2008, 18:38:20 UT at a distance of 802.6 km. The spacecraft passed on the sunlit side of the asteroid with a relative velocity of 8.6 km/s in the plane defined by the relative velocity vector and the Sun direction. This fly-by strategy allowed continuous pointing on the asteroid before, during and after closest approach as well as passing through a phase angle close to zero. The minimum phase angle (0.27°) was reached at 18:36:23, about 2 minutes before closest approach. Optical navigation on the asteroid started already on 4 August 2008 as the spacecraft had to target the small asteroid (effective radius ~ 5 km) within accuracy better than 2 km to keep it in the field of view of the science instruments during closest approach. In addition an attitude flip manoeuvre of 20 minutes duration was performed before autonomous tracking on asteroid (2867) Steins started. Altogether 14 instruments were switched on during the fly-by, providing spatially resolved multi-wavelength observations of the asteroid and in-situ measurements of its dust, plasma, magnetic, and radiation environment. Its detailed characterization will add to the understanding the different types of asteroids and to solving the puzzle of how the solar system formed and evolved. (2867) Steins was Rosetta's first nominal scientific target in its 11.5-year mission. The next scientific encounter is however already in view. In July 2010 Rosetta will fly-by at asteroid (21) Lutetia, a 100 km-sized object (95.5 ± 4.1 km) before moving out to Jupiter's orbit to meet and explore the nucleus of 67P/Churyumov-Gerasimenko.

  13. The Main Asteroid Belt: The Crossroads of the Solar System

    Science.gov (United States)

    Michel, Patrick

    2015-08-01

    Orbiting the Sun between Mars and Jupiter, main belt asteroids are leftover planetary building blocks that never accreted enough material to become planets. They are therefore keys to understanding how the Solar System formed and evolved. They may also provide clues to the origin of life, as similar bodies may have delivered organics and water to the early Earth.Strong associations between asteroids and meteorites emerged thanks to multi-technique observations, modeling, in situ and sample return analyses. Spacecraft images revolutionized our knowledge of these small worlds. Asteroids are stunning in their diversity in terms of physical properties. Their gravity varies by more orders of magnitude than its variation among the terrestrial planets, including the Moon. Each rendezvous with an asteroid thus turned our geological understanding on its head as each asteroid is affected in different ways by a variety of processes such as landslides, faulting, and impact cratering. Composition also varies, from ice-rich to lunar-like to chondritic.Nearly every asteroid we see today, whether of primitive or evolved compositions, is the product of a complex history involving accretion and one or more episodes of catastrophic disruption that sometimes resulted in families of smaller asteroids that have distinct and indicative petrogenic relationships. These families provide the best data to study the impact disruption process at scales far larger than those accessible in laboratory. Tens, perhaps hundreds, of early asteroids grew large enough to thermally differentiate. Their traces are scattered pieces of their metal-rich cores and, more rarely, their mantles and crusts.Asteroids represent stages on the rocky road to planet formation. They have great stories to tell about the formation and evolution of our Solar System as well as other planetary systems: asteroid belts seem common around Sun-like stars. We will review our current knowledge on their properties, their link to

  14. 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

  15. Thermophysical modeling of main-belt asteroids from WISE data

    Science.gov (United States)

    Hanuš, J.; Delbó, M.; Durech, J.; Alí-Lagoa, V.

    2014-07-01

    We determine asteroid physical parameters such as size, surface roughness, albedo, and thermal inertia by applying the implementation of the thermophysical model (TPM) of Lagerros (1996; 1997; 1998) to the thermal data obtained by the NASA WISE satellite. We present thermophysical parameters for ˜150 asteroids, which gives us so far the largest sample of asteroids with determined values of thermal inertia. On several individual cases, we discuss the reliability of our determinations and limitations of the TPM method we use. As initial shapes, we adopt convex shape models from the DAMIT database (Durech et al., 2010) and present new determinations based on combined dense and sparse-in-time disk-integrated photometry and the lightcurve inversion method (Kaasalainen & Torppa 2001; Kaasalainen et al., 2001). We use thermal data from the WISE filters W3 and W4, as well as the data observed by the IRAS satellite. However, due to the intriguing accuracy of the fluxes and larger amount of measurements, the WISE data are significantly more important and dominate the modeling. The WISE data are processed the same way as in Alí-Lagoa et al. (2014) for asteroid (341 843) 2008 EV_5. We show the main results of the study of derived thermophysical parameters within the whole population of MBAs and within several asteroid families with the main focus on the thermal inertia. The thermal inertia increases with decreasing size (as previously shown by Delbó et al., 2007), but a large range of thermal inertia values is observed within the similar size ranges between D˜10-100 km. Surprisingly, we derived very low (<10 J m^{-2} s^{-1/2} K^{-1}) thermal inertias for many asteroids (˜20) with various sizes. The range of thermal inertia values is large even within a few asteroid families.

  16. Estimating Asteroid Thermal Inertia from Multi-epoch Observations

    Science.gov (United States)

    MacLennan, Eric M.; Emery, Joshua P.

    2014-11-01

    Granular material, or regolith, is observed to be ubiquitous on asteroid surfaces. To date, two feasible mechanisms of regolith generation have been proposed: recurrent impacts and thermal fracturing. By combining thermal infrared observations and a thermophysical model (TPM), the thermal inertia of an asteroid surface can be used to infer its physical properties, including the average regolith grain size. With the regolith properties of a large population of diverse asteroids (i.e. different spectral class, size, rotation period etc.), information regarding the details of regolith generation can be inferred.Traditional thermal inertia determination methods use a TPM with a previously derived asteroid shape model and spin axis for constraining the observed surface temperature distribution. TPMs invoke the heat diffusion equation to calculate surface temperatures for a rotating asteroid. An asteroid spin axis provide the boundary condition needed to calculate the surface energy balance in a TPM. However the limited amount of objects with a shape model and thermal infrared observations inhibit the number of thermal inertias that can potentially be calculated. Here, a technique using WISE (12 & 22 μm) observations taken before or after opposition is employed to derive thermal inertias of asteroids without using a shape model. By gathering thermal infrared data at multiple viewing geometries the temperature distribution, thus thermal inertia, is constrained.We first demonstrate the validity of this method on objects with a previously determined shape model and spin axis from the DAMIT website. Our analyses show that not knowing an asteroid’s shape does not significantly affect the resulting thermal inertia estimates. Additionally, we apply our TPM to WISE multi-epoch thermal observations to place estimates for the thermal inertia for more than 100 objects. The set of objects used samples many sizes, spectral classes and rotation periods, which may be important

  17. Max Wolf's Discovery of Near-Earth Asteroid 887 Alinda

    Science.gov (United States)

    Connors, Martin; Mandel, Holger; Demleitner, Markus; Heidelberg Digitized Astronomical Plates Project

    2016-01-01

    Max Wolf, director of the Heidelberg Observatory (Landessternwarte Königsstuhl), was the most prodigious discoverer of asteroids in the early twentieth century. He is now best known for the discovery of the Trojan asteroids associated with Jupiter in 1906, but was a pioneer in the application of photographic techniques to astronomy, particularly for conducting asteroid surveys. His attention to detail and perseverance also led to the discovery of the near-Earth asteroid 887 Alinda, which is the eponym of an orbital class in 3:1 resonance with Jupiter. Alinda class contains several potentially hazardous asteroids, and has been particularly instructive in development of theories of eccentricity increase for resonant asteroids. Alinda was discovered on January 3, 1918, on the very edge of one of two plates taken with the 40 cm aperture Bruce double astrograph. The inability to reduce a long trail going off the plate meant that only one month later could the object again be found with the Bruce telescope, and later observed with the follow-up instrument, the 72 cm aperture Waltz reflector. In what Wolf referred to as "the greatest embarrassment of my life", reflector observations had him conclude that Alinda had a satellite. At a time when plates had to be exposed for several hours, laboriously developed and analyzed, and in the case of high eccentricity objects like Alinda, predicted with inadequate theories, Wolf's persistence allowed it never to be lost. Despite this, its essential resonant nature was not determined until 1969, despite the pioneering work by Brown (1911) on resonance in the asteroid belt and the knowledge dating to the late nineteenth century work of Kirkwood that commensurabilities were important in its structure. The majority of Wolf's plates are available as online scans through the Heidelberg Digitized Astronomical Plates project of the German Astrophysical Virtual Observatory, but the Alinda discovery plate, which was broken, was scanned

  18. Discovery of a Satellite around a Near-Earth Asteroid

    Science.gov (United States)

    1997-07-01

    In the course of the major observational programme of asteroids by the Institute of Planetary Exploration of the German Aerospace Research Establishment (DLR) [1] in Berlin, two of the staff astronomers, Stefano Mottola and Gerhard Hahn , have discovered a small satellite (moon) orbiting the asteroid (3671) Dionysus. The new measurements were obtained with the DLR CCD Camera attached at the 60-cm Bochum telescope at the ESO La Silla Observatory in Chile. This is only the second known case of an asteroid with a moon. Moons and planets Until recently, natural satellites were only known around the major planets . The Moon orbits the Earth, there are two tiny moons around Mars, each of the giant planets Jupiter, Saturn, Uranus and Neptune has many more, and even the smallest and outermost, Pluto, is accompanied by one [2]. However, the new discovery now strengthens the belief of many astronomers that some, perhaps even a substantial number of the many thousands of minor planets (asteroids) in the solar system may also possess their own moons. The first discovery of a satellite orbiting an asteroid was made by the NASA Galileo spacecraft, whose imagery, obtained during a fly-by of asteroid (253) Ida in August 1993, unveiled a small moon that has since been given the name Dactyl. (3671) Dionysus: an Earth-crossing asteroid In the framework of the DLR asteroid monitoring programme, image sequences are acquired to measure an asteroid's brightness variations caused by the changing amount of sunlight reflected from the asteroid's illuminated surface as it spins, due to its irregular shape. The brightness variations may be used to derive the asteroid's rotational properties, such as speed of rotation and spin axis orientation. Asteroid Dionysus [3] was put on the observing list because it belongs to a special class of asteroids, the members of which occasionally come very close to the Earth and have a small, but non-negligible chance of colliding with our planet. Most of

  19. 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.

  20. Near-Earth Asteroid (NEA) Scout

    Science.gov (United States)

    McNutt, Leslie; Johnson, Les; Kahn, Peter; Castillo-Rogez, Julie; Frick, Andreas

    2014-01-01

    Near-Earth asteroids (NEAs) are the most easily accessible bodies in the solar system, and detections of NEAs are expected to grow exponentially in the near future, offering increasing target opportunities. As NASA continues to refine its plans to possibly explore these small worlds with human explorers, initial reconnaissance with comparatively inexpensive robotic precursors is necessary. Obtaining and analyzing relevant data about these bodies via robotic precursors before committing a crew to visit a NEA will significantly minimize crew and mission risk, as well as maximize exploration return potential. The Marshall Space Flight Center (MSFC) and Jet Propulsion Laboratory (JPL) are jointly examining a potential mission concept, tentatively called 'NEAScout,' utilizing a low-cost platform such as CubeSat in response to the current needs for affordable missions with exploration science value. The NEAScout mission concept would be treated as a secondary payload on the Space Launch System (SLS) Exploration Mission 1 (EM-1), the first planned flight of the SLS and the second un-crewed test flight of the Orion Multi-Purpose Crew Vehicle (MPCV).

  1. 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...

  2. 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...

  3. 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...

  4. 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...

  5. The WISE Survey of the Albedo Distribution of Main Belt Asteroids

    NARCIS (Netherlands)

    Masiero, J.; Mainzer, A.; Grav, T.; Delbó, M.; Mueller, M.; WISE Team, [No Value

    2010-01-01

    Using date from the Wide-field Infrared Survey Explorer (WISE) we investigate the albedo distribution across the main belt of asteroids. When complete WISE will measure albedos and diameters for ~100,000 asteroids.

  6. Slowly increasing elongations of non-spherical asteroids caused by collisions

    CERN Document Server

    Henych, T

    2015-01-01

    Asteroids are frequently colliding with small projectiles. Although each individual small collision is not very important, their cumulative effect can substantially change topography and also the overall shape of an asteroid. We run simulations of random collisions onto a single target asteroid represented by triaxial ellipsoid. We investigated asteroids of several hundred meters to about 18 km in diameter for which we assumed all material excavated by the collision to escape the asteroid. The cumulative effect of these collisions is an increasing elongation of the asteroid figure. However, the estimated timescale of this process is much longer than the collisional lifetime of asteroids. Therefore, we conclude that small collisions are probably not responsible for the overall shape of small asteroids.

  7. 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

  8. The seismic effect of impacts on asteroid surface morphology

    Science.gov (United States)

    Richardson, James Edward, Jr.

    Impact-induced seismic vibrations have long been suspected of being an important surface modification process on small satellites and asteroids. In this study, I use a series of linked seismic and geomorphic models to investigate the process in detail. I begin by developing a basic theory for the propagation of seismic energy in a highly fractured asteroid, and I use this theory to model the global vibrations experienced on the surface of an asteroid following an impact. These synthetic seismograms are then applied to a model of regolith resting on a slope, and the resulting downslope motion is computed for a full range of impactor sizes. Next, this computed downslope regolith flow is used in a morphological model of impact crater degradation and erasure, showing how topographic erosion accumulates as a function of time and the number of impacts. Finally, these results are applied in a stochastic cratering model for the surface of an Eros-like body (same volume and surface area as the asteroid), with craters formed by impacts and then erased by the effects of superposing craters, ejecta coverage, and seismic shakedown. This simulation shows good agreement with the observed 433 Eros cratering record at a Main Belt exposure age of 400 +/- 200 Myr, including the observed paucity of small craters. The lowered equilibrium numbers floss rate = production rate) for craters less than ~100 m in diameter is a direct result of seismic erasure, which requires less than a meter of mobilized regolith to reproduce the NEAR observations. This study also points to an upper limit on asteroid size for experiencing global, surface-modifying, seismic effects from individual impacts of about 70- 100 km (depending upon asteroid seismic properties). Larger asteroids will experience only local seismic effects from individual impacts. In addition to the study of global seismic effects on asteroids, a chapter is also included which details the impact ejecta plume modeling I have done for the

  9. 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

  10. 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

  11. PRODUCTION OF NEAR-EARTH ASTEROIDS ON RETROGRADE ORBITS

    Energy Technology Data Exchange (ETDEWEB)

    Greenstreet, S.; Gladman, B. [Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia (Canada); Ngo, H. [Department of Physics, Engineering Physics, and Astronomy, Queen' s University, Kingston, Ontario (Canada); Granvik, M. [Department of Physics, University of Helsinki, Helsinki (Finland); Larson, S., E-mail: sarahg@phas.ubc.ca [Department of Planetary Sciences, University of Arizona, Tucson, Arizona (United States)

    2012-04-20

    While computing an improved near-Earth object (NEO) steady-state orbital distribution model, we discovered in the numerical integrations the unexpected production of retrograde orbits for asteroids that had originally exited from the accepted main-belt source regions. Our model indicates that {approx}0.1% (a factor of two uncertainty) of the steady-state NEO population (perihelion q < 1.3 AU) is on retrograde orbits. These rare outcomes typically happen when asteroid orbits flip to a retrograde configuration while in the 3:1 mean-motion resonance with Jupiter and then live for {approx}0.001 to 100 Myr. The model predicts, given the estimated near-Earth asteroid (NEA) population, that a few retrograde 0.1-1 km NEAs should exist. Currently, there are two known MPC NEOs with asteroidal designations on retrograde orbits which we therefore claim could be escaped asteroids instead of devolatilized comets. This retrograde NEA population may also answer a long-standing question in the meteoritical literature regarding the origin of high-strength, high-velocity meteoroids on retrograde orbits.

  12. Planet-crossing asteroids: Interrelationships within the solar system

    Science.gov (United States)

    Mcfadden, L. A.; Ahearn, M. F.

    1986-01-01

    Near-infrared reflectance spectra 0.6 to 2.5 micrometer were acquired of asteroids 1627 Ivar (Amor), 43 Ariadne, 335 Roberta, 386 Siegena and 695 Bella (3:1 Kirkwood Gap) with the IRTF, Mauna Kea. CCD spectra 0.5-1.0 micrometer were acquired of 1866 Sisyphus (Apollo), 17 Thetis, 695 Bella, 797 Montana, and 877 Walkure (3:1 Kirkwood Gap) using facilities at Cerro Tololo Inter-American Observatory. An upper limit on the production rate of CN in asteroid 3200 Phaeton of < 4 x 10 to the 23rd power sec was determined based on photometric measurements at 3871A using facilities at Lowell Observatory. This value is in the range of the lowest production rate measured for a comet, however, it does not constitute a positive detection of CN in this asteroid. A first attempt of look for companion objects or evidence of dust debris associated with this asteroid was made with a CCD camera. Whereas the search extended to 19th magnitude (corresponding to 150m and 330m for albedos of 0.15 and 0.03 respectively), a look close enough to the asteroid was not attained to definitively eliminate the presence of coorbiting dust debris.

  13. Rosetta fly-by at asteroid (21) Lutetia: An overview

    Science.gov (United States)

    Schulz, R.; Sierks, H.; Küppers, M.; Accomazzo, A.

    2012-06-01

    On the journey to its target comet 67P/Churyumov-Gerasimenko the ESA Rosetta spacecraft had a close fly-by at the main-belt asteroid (21) Lutetia at a heliocentric distance of r=2.72 AU, and a geocentric distance of Δ=3.05 AU. Closest approach occurred on 10 July 2010, 15:45 UT at a distance of ˜3170 km. Rosetta passed the asteroid with a relative fly-by velocity of 15 km/s. The fly-by strategy allowed continuous observations of (21) Lutetia before, during and for 30 min after closest approach, and the spacecraft to go through zero phase angle 18 min before closest approach at a distance of 16400 km from the asteroid. Most of the scientific instruments on board Rosetta were switched on obtaining imaging and spectral observations covering wavelengths from the UV to sub-mm, as well as in-situ measurements of the asteroid and its direct environment. A brief summary of the fly-by is provided concentrating mainly on an overview of the instrument operations, the visual appearance of the asteroid during the encounter, and a synopsis of the fly-by results published in this special issue.

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

    Science.gov (United States)

    Carruba, V.; Nesvorný, D.

    2016-04-01

    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 analyse 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 (vW). From modelling the initial break up, we find that the distribution of vW 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 Gaussian. We surveyed known asteroid families for signs of a peaked distribution of vW using a statistical measure of the distribution peakedness or flatness known as kurtosis. We identified eight families whose vW distribution is significantly leptokurtic. These cases (e.g. the Koronis family) are located in dynamically quiet regions of the main belt, where, presumably, the initial distribution of vW was not modified by subsequent orbital evolution. We suggest that, in these cases, the inclination distribution can be used to obtain interesting information about the original ejection velocity field.

  15. 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...

  16. 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.

  17. 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...

  18. The Explored Asteroids: Science and Exploration in the Space Age

    Science.gov (United States)

    Sears, D. W. G.

    2015-11-01

    Interest in asteroids is currently high in view of their scientific importance, the impact hazard, and the in situ resource opportunities they offer. They are also a case study of the intimate relationship between science and exploration. A detailed review of the twelve asteroids that have been visited by eight robotic spacecraft is presented here. While the twelve explored asteroids have many features in common, like their heavily cratered and regolith covered surfaces, they are a remarkably diverse group. Some have low-eccentricity orbits in the main belt, while some are potentially hazardous objects. They range from dwarf planets to primary planetesimals to fragments of larger precursor objects to tiny shards. One has a moon. Their surface compositions range from basaltic to various chondrite-like compositions. Here their properties are reviewed and what was confirmed and what was newly learned is discussed, and additionally the explored asteroids are compared with comets and meteorites. Several topics are developed. These topics are the internal structure of asteroids, water distribution in the inner solar system and its role in shaping surfaces, and the meteoritic links.

  19. ASTEX – an in-situ exploration mission to two near-Earth asteroids

    OpenAIRE

    Nathues, A.; Boehnhardt, H.; Harris, A. W.; Goetz, W.; Gritzner, C.; Jentsch, C.; Schmitz, N.; Schaeff, S.; Weischede, F.; Wiegand, A.

    2008-01-01

    ASTEX is a feasibility study of an in-situ exploration mission to two near-Earth asteroids (NEAs) funded by the German Space Agency DLR. The mission objectives call for targets with different mineralogical compositions: one asteroid should be of “primitive'' nature, the other one should be a fragment of a differentiated asteroid. The goals of the mission are to explore the physical, geological and mineralogical nature of the asteroids and to provide information and constraints on the formatio...

  20. Thermal inertia of near-Earth asteroids and implications for the magnitude of the Yarkovsky effect

    NARCIS (Netherlands)

    Delbo', Marco; dell'Oro, Aldo; Harris, Alan W.; Mottola, Stefano; Mueller, Michael

    2007-01-01

    Thermal inertia determines the temperature distribution over the surface of an asteroid and therefore governs the magnitude the Yarkovsky effect. The latter causes gradual drifting of the orbits of km-sized asteroids and plays an important role in the delivery of near-Earth asteroids (NEAs) from the

  1. Thermal Inertia of near-Earth Asteroids and Strength of the Yarkovsky Effect

    NARCIS (Netherlands)

    Delbo, Marco; Dell'Oro, A.; Harris, A. W.; Mottola, S.; Mueller, M.

    2006-01-01

    Thermal inertia is the physical parameter that controls the temperature distribution over the surface of an asteroid. It affects the strength of the Yarkovsky effect, which causes orbital drift of km-sized asteroids and is invoked to explain the delivery of near-Earth asteroids (NEAs) from the main

  2. Surface Properties of Asteroids from Mid-Infrared Observations and Thermophysical Modeling

    NARCIS (Netherlands)

    Mueller, Michael

    2007-01-01

    The subject of this work is the physical characterization of asteroids, focusing on the thermal inertia of near-Earth asteroids (NEAs). Thermal inertia governs the Yarkovsky effect, a non-gravitational force which significantly alters the orbits of asteroids up to \\sim 20 km in diameter. Yet, very l

  3. 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

  4. Geo-Statistical Approach to Estimating Asteroid Exploration Parameters

    Science.gov (United States)

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

    2011-01-01

    NASA's vision for space exploration calls for a human visit to a near earth asteroid (NEA). Potential human operations at an asteroid include exploring a number of sites and analyzing and collecting multiple surface samples at each site. In this paper two approaches to formulation and scheduling of human exploration activities are compared given uncertain information regarding the asteroid prior to visit. In the first approach a probability model was applied to determine best estimates of mission duration and exploration activities consistent with exploration goals and existing prior data about the expected aggregate terrain information. These estimates were compared to a second approach or baseline plan where activities were constrained to fit within an assumed mission duration. The results compare the number of sites visited, number of samples analyzed per site, and the probability of achieving mission goals related to surface characterization for both cases.

  5. 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...

  6. 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.

  7. Collisions, Cosmic Radiation and the Colors of the Trojan Asteroids

    CERN Document Server

    Melita, M D; Bar-Nun, A

    2009-01-01

    The Trojan asteroids orbit about the Lagrangian points of Jupiter and the residence times about their present location are very long for most of them. If these bodies originated in the outer Solar System, they should be mainly composed of water ice, but, in contrast with comets, all the volatiles close to the surface would have been lost long ago. Irrespective of the rotation period, and hence the surface temperature and ice sublimation rate, a dust layer exists always on the surface. We show that the timescale for resurfacing the entire surface of the Trojan asteroids is similar to that of the flattening of the red spectrum of the new dust by solar-proton irradiation. This, if the cut-off radius of the size distribution of the impacting objects is between 1mm and 1m and its slope is -3, for the entire size-range. Therefore, the surfaces of most Trojan asteroids should be composed mainly of unirradiated dust.

  8. The daily processing of asteroid observations by Gaia

    CERN Document Server

    Tanga, Paolo; Oro, Aldo Dell; Muinonen, Karri; Pauwels, Thierry; Thuillot, William; Berthier, Jerome; Cellino, Alberto; Hestroffer, Daniel; Petit, Jean-Marc; Carry, Benoit; David, Pedro; Delbo, Marco; Fedorets, Grigori; Galluccio, Laurent; Granvik, Mikael; Ordenovic, Christophe; Pentikainen, Hanna

    2015-01-01

    The Gaia mission started its regular observing program in the summer of 2014, and since then it is regularly obtaining observations of asteroids. This paper draws the outline of the data processing for Solar System objects, and in particular on the daily "short-term" processing, from the on-board 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 some tests and validations of the processing of the asteroid observations. Our findings are overall consistent with the expectations concerning the performances of Gaia and the effectiveness of the developed software for data reduction.

  9. 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...

  10. Reflectance of Asteroid 4179 Toutatis Based on Space Optical Image

    Science.gov (United States)

    Zhao, D. F.; Liu, P.; Zhao, W.; Huang, C. N.; Zhang, H. W.; Tang, X. L.

    2016-01-01

    On 2012 December 13, Chang'e-2 probe made a success flyby for Asteroid 4179 Toutatis in deep space of about 7 million kilometers away from the earth, and acquired a series of optical images with high resolution better than 3 m. In this paper, we process the radiation calibration data of imaging camera by least square fitting method, to obtain the absolute calibration coefficient and relative calibration correction matrix, and to recover original intensity of asteroid and its real surface radiance. According to the Nicodemus' reflectance definition proposed by Hapke, the directional-hemispherical reflectance of Toutatis is obtained. The average surface albedo in R, G, and B spectrum bands are 0.2083, 0.1269, and 0.1346, respectively, and the asteroid's surface albedo is 0.1566. Data indicate that, Toutatis is, somewhat, a red body in visible spectrum.

  11. Possible explanation of total ablation of the 1908 Tunguska asteroid

    Energy Technology Data Exchange (ETDEWEB)

    Hassanein, A. [Argonne National Lab., IL (United States); Alekseev, V.A.; Konkashbaev, A.I.; Konkashbaev, I.K.; Nikandrov, L.B. [Troitsk Inst. for Innovation and Fusion Research, Troitsk (Russian Federation)

    1998-01-01

    Damage to the Earth`s surface from colliding asteroids and comets is of great concern, and the first conference on this subject, ``Space Protection of the Earth,`` took place September 26--30, 1995 (Snezhinsk, Chelyabinsk region, Russia). The explosion over Tunguska, Central Siberia, in 1908 is believed to be due to breakup of a stony asteroids. However, because no significant fragments have been located in the area of the explosion, the nature of the object over Tunguska remains to be determined. Recent theoretical models and results of experiments performed to evaluate material erosion in high-heat-load environments are used to analyze the interaction between the Tunguska object and Earth`s atmosphere. Models and laboratory experimental data that indicate the possibility of full destruction of such large-sized asteroid objects are presented.

  12. Five-color photoelectric photometry of asteroid 433 Eros

    Science.gov (United States)

    Miner, E.; Young, J.

    1976-01-01

    Five-color (UVBGR) photoelectric light curves of Eros are presented which were obtained on nine nights during the asteroid's 1974/75 close apparition. Indications that three reversals occurred in the relative depths of the two minima between late December 1974 and late January 1975 are noted along with definite evidence of phase reddening. The maximum amplitude observed was 1.44 magnitudes, and the absolute visual magnitude at primary maximum (corrected to zero phase and to 1 AU from the earth and the sun) was about 10.8 magnitudes. Since the observations indicate that Eros has no significant rotational color variations, it is suggested that the light-curve amplitudes are due primarily to the asteroid's shape and to shadowing effects. Based on its colors relative to the sun, it is concluded that Eros appears to be an S-type asteroid.

  13. 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.

  14. Passive Sorting of Asteroid Material Using Solar Radiation Pressure

    CERN Document Server

    Yárnoz, Daniel García; McInnes, Colin R

    2014-01-01

    Understanding dust dynamics in the vicinity of asteroids is key for future science missions and, in the long-term, for asteroid exploitation. This paper analyzes the feasibility of manipulating asteroid material by means of solar radiation pressure. A novel method is proposed for passively sorting material as a function of its grain size or density, where solar radiation pressure is used as a passive in-situ "mass spectrometer". A simplified analysis shows that in principle this method allows an effective sorting of regolith material. This could have immediate applications for a sample return mission, and for industrial scale in-situ resource utilization to separate and concentrate regolith according to particle size or composition.

  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. 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.

  17. 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.

  18. Star catalog position and proper motion corrections in asteroid astrometry

    CERN Document Server

    Farnocchia, D; Chamberlin, A B; Tholen, D J

    2014-01-01

    We provide a scheme to correct asteroid astrometric observations for star catalog systematic errors due to inaccurate star positions and proper motions. As reference we select the most accurate stars in the PPMXL catalog, i.e., those based on 2MASS astrometry. We compute position and proper motion corrections for 19 of the most used star catalogs. The use of these corrections provides better ephemeris predictions and improves the error statistics of astrometric observations, e.g., by removing most of the regional systematic errors previously seen in Pan-STARRS PS1 asteroid astrometry. The correction table is publicly available at ftp://ssd.jpl.nasa.gov/pub/ssd/debias/debias_2014.tgz and can be freely used in orbit determination algorithms to obtain more reliable asteroid trajectories.

  19. 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...

  20. On the asteroidal conductivities as inferred from meteorites

    International Nuclear Information System (INIS)

    Solar wind interactions with planetary bodies without intrinsic magnetic fields depend to a large extent on the electrical conductivities of the objects in question. If the combined (i.e., ionospheric and interior) electrical conductivities are large, as in the case of Venus, the solar wind interaction is strong due to the generation of a large electrical current flow. It is suggested here that a similar interaction may occur at some asteroids, if their interior conductivity can be approximated by the conductivities of carbonaceous or iron-bearing meteorites. This interaction, in turn, can be used as a tool for remote sensing of the asteroidal interior properties in a spacecraft mission to asteroids. (Auth.)

  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. Threat from Rubble-Pile Asteroids

    Science.gov (United States)

    Schultz, P. H.

    2015-12-01

    While chondrites are the most common meteoroids to enter our atmosphere, they represent a small fraction of recovered falls. Most stony meteorites disrupt during entry, consumed by ablation or lost by weathering; in contrast, small iron meteorites (entry at altitude; (c) no accessory meteorite falls; (d) "explosion" (not low-speed compression) crater; (e) infrasound/seismic data indicating a high-speed entry/collision; and (f) petrologic evidence for shock deformation/melting in breccias indicative of speeds >4 km/s. Although a monolithic chondrite (~ 10 m across) might allow surviving entry, most objects of this size contain multiple flaws, ensuring atmospheric disruption. Hence, an alternative "needle model" was proposed wherein a small rubble-pile object gradually re-shaped itself during entry [Schultz, 2008], a process that minimizes drag, thermal signatures of entry, and catastrophic disruption. First proposed to account for smaller than expected craters on Venus [Schultz, 1992], such a process resembles subsequent Shoemaker-Levy entry models [Boslough and Crawford, 1997] that predicted much deeper entry than standard models. Laboratory experiments at the NASA Ames Vertical Gun Range simulated this process by breaking-up hypervelocity projectiles into a cloud of debris and tracking its path at near-full atmospheric pressure. The resulting cloud of fragments exhibited less deceleration than a solid sphere at the same speed. Moreover, shadowgraphs revealed constituent fragments "surfing" the pressure jump within the mach cone/column. Previous models proposed that crater-forming impacts must be >50-100 m in diameter in order to survive entry [Bland and Artemieva, 2004]. The "needle model" for the Carancas meteorite entry, however, raises questions about this lower limit for threats by rubble-pile asteroids, e.g., Itokawa. Consequently, we modeled the fate of a rubble-pile entering earth's atmosphere using GEODYN, an Eulerian code with adaptive mesh refinement

  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. 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.

  5. A Mobile Asteroid Surface Scout for the AIDA Mission

    Science.gov (United States)

    Ho, Tra Mi; Lange, Caroline; Grimm, Christian; Thimo Grundmann, Jan; Rößler, Johannes; Schröder, Silvio; Skoczylas, Thomas; Ziach, Christian; Biele, Jens; Cozzoni, Barbara; Krause, Christian; Küchemann, Oliver; Maibaum, Michael; Ulamec, Stephan; Lange, Michael; Mierheim, Olaf; Maier, Maximilian; Herique, Alain; Mascot Study Team

    2016-04-01

    The Asteroid Impact Deflection, AIDA, mission is composed of a kinetic impactor, DART and an observer, the Asteroid Impact Monitor, AIM, carrying among other payload a surface package, MASCOT2 (MSC2). Its proposed concept is based on the MASCOT lander onboard the HAYABUSA2 Mission (JAXA) to near-Earth asteroid (162173) Ryugu. MASCOT is a compact platform ('shoe box size') carrying a suite of 4 scientific instruments and has a landed mass of ~10kg. Equipped with a mobility mechanism, the MASCOT lander is able to upright and relocate on the targeted asteroid; thus providing in-situ data at more than one site. In the context of the AIDA Mission, the MASCOT2 lander would be carried by the AIM spacecraft and delivered onto Didymoon, the secondary object in the (65803) Didymos binary near-Earth asteroid system. Since the mission objectives of the AIM mission within the joint AIDA mission concept differ from JAXA's sample return mission HAYABUSA2, several design changes need to be studied and implemented. To support one of the prime objectives of the AIM mission, the characterization of the bulk physical properties of Didymoon, the main scientific payload of MSC2 is a low-frequency radar (LFR) to investigate the internal structure of the asteroid moon. Since the total science payload on MASCOT2 is limited to approximately 2.3 kg, the mass remaining for a suite of other experiments is in the range of 0.1 to 0.5 kg per instrument. Further requirements have a significant impact on the MSC2 design which will be presented. Among these are the much longer required operational lifetime than for MASCOT on HAYABUSA2, and different conditions on the target body such as an extremely low gravity due to its small size of Ø_[Didymoon] ~ 150m.

  6. 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.

  7. 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.

  8. 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.

  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. Detection of earth-approaching asteroids in near real time

    Science.gov (United States)

    Rabinowitz, D. L.

    1991-01-01

    Computer software, called the Moving Object Detection Program (MODP), is described which detects earth-approaching asteroids in near real time. The software runs on a workstation linked to the output of the drift-scanning CCD camera of the Spacewatch Telescope. MOPD recognizes trailed images, detects motion, and accurately determines angular positions and rates of motion for moving objects in the scan images. The results are obtained a few seconds after the image signals are shifted out of the CCD. During 2 months of trial observations with this system, 304 asteroids were detected down to a limiting apparent magnitude for untrailed images of V = 20.5.

  11. 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.

  12. 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.

  13. Polarization of the reflected light of asteroid 433 Eros

    Science.gov (United States)

    Zellner, B.; Gradie, J.

    1976-01-01

    Linear polarizations measured for asteroid 433 Eros at various wavelengths and at solar phase angles ranging from 9 to 53 deg are presented. The polarization results are entirely typical of main-belt S asteroids, and indicate a dusty surface with geometric albedo 0.20. The derived effective diameter at photometric maximum is 21 km. Eros is quite uniform polarimetrically; no dependence on aspect is detected, and the polarization is shown to be constant during a single rotation with a precision of one part in forty.

  14. 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.

  15. 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

  16. 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

  17. 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.

  18. 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

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

    OpenAIRE

    Ji, Jianghui; Jiang, Yun; 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 thi...

  20. 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...

  1. Multiple main-belt asteroid mission options for a Mariner Mark II spacecraft

    Science.gov (United States)

    Sauer, Carl G., Jr.; Yen, Chen-Wan L.

    1990-01-01

    This paper presents the trajectory options available for a MMII spacecraft mission to asteroids and introduces systematic methods of uncovering attractive mission opportunities. The analysis presented considers multiple synchronous gravity assists of Mars and introduces a terminal resonant or phasing orbit; a concept useful for both increasing the number of asteroid rendezvous targets attainable during a launch opportunity, and also in increasing the number of potential asteroid flybys. Systematic examinations of the requirements for superior asteroidal alignments are made and a comprehensive set of asteroid rendezvous opportunities for the 1998 to 2010 period are presented. Examples of candidate missions involving one or more rendezvous and several flybys are also presented.

  2. 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.

  3. Consequences of impacts of small asteroids and comets with Earth

    Science.gov (United States)

    Hills, J. G.

    The fragmentation of a small asteroid in the atmosphere greatly increases its cross sections for aerodynamic braking and energy dissipation. At a typical impact velocity of 22 km/s, the atmosphere absorbs more than half the kinetic energy of stony meteoroids with diameters, D(sub m), less than 220 m and iron meteoroids with D(sub m) less than 80 m. The corresponding diameter for comets with impact velocity 50 km/s is D(sub m) less than 1600 m. Most of the atmospheric energy dissipation occurs in a fraction of a scale height, so large meteors appear to 'explode' or 'flare' at the end of their visible paths. This dissipation of energy in the atmosphere protects the earth from direct impact damage (e.g., craters), but it produces a blast wave that can do considerable damage. The area of destruction around the impact point in which the over-pressure in the blast wave exceeds 4 lb/sq in = 2.8 x 10(exp 5) dynes/cu cm, which is enough to knock over trees and destroy buildings, increases rapidly from zero for chondritic meteoroids less than 56 m in diameter (15 megatons) to about 200 sq km for those 80 m in diameter (48 megatons); the probable diameter of the tunguska impactor of 1908 is about 80 m. Crater formation and earthquakes are not significant in land impacts by stony asteroids less than about 200 m in diameter because of the air protection. A tsunami is probably the most devastating type of damage for asteroids 200 m to 1 km in diameter. An impact by an asteroid this size anywhere in the Atlantic would devastate coastal areas on both sides of the ocean. An asteroid a few kilometers across would produce a tsunami that would reach the foothills of the Appalachian Mountains in the upper half of the East Coast of the United States. Most of Florida is protected from a tsunami by the gradual slope of the ocean off its coast, which causes most of the tsunami energy to be reflected back into the Atlantic. The atmosphere plume produced by asteroids with diameters exceeding

  4. Simulations of impacts on rubble-pile asteroids

    Science.gov (United States)

    Deller, J.; Snodgrass, C.; Lowry, S.; Price, M.; Sierks, H.

    2014-07-01

    Rubble-pile asteroids can contain a high level of macroporosity. For some asteroids, porosities of 40 % or even more have been measured [1]. While little is known about the exact distribution of the voids inside rubble-pile asteroids, assumptions have to be made for the modeling of impact events on these bodies. Most hydrocodes do not distinguish between micro- and macroporosity, instead describing brittle material by a constitutive model as homogeneous. We developed a method to model rubble-pile structures in hypervelocity impact events explicitly. The formation of the asteroid is modelled as a gravitational aggregation of spherical `pebbles', that form the building blocks of our target. This aggregate is then converted into a high-resolution Smoothed Particle Hydrodynamics (SPH) model, which also accounts for macroporosity inside the pebbles. We present results of a study that quantifies the influence of our model parameters on the outcome of a typical impact event of two small main-belt asteroids. The existence of void space in our model increases the resistance against collisional disruption, a behavior observed before [2]. We show that for our model no a priori knowledge of the rubble-pile constituents in the asteroid is needed, as the choice of the corresponding parameters does not directly correlate with the impact outcome. The size distribution of the pebbles used as building blocks in the formation of an asteroid is only poorly constrained. As a starting point, we use a power law N(>r) ∝ r^α to describe the distribution of radii of the pebbles. Reasonable values for the slope α range around α=-2.5, as found in the size distribution of main-belt objects [3,4]. The cut-off values for pebbles, r_{min} and r_{max} are given by practical considerations: In the SPH formalism, properties are represented by weighted averages of particles within their smoothing length h, preventing the resolution of structures below that scale. Using spheres with radius in the

  5. Consequences of impacts of small asteroids and comets with Earth

    Science.gov (United States)

    Hills, J. G.

    1994-01-01

    The fragmentation of a small asteroid in the atmosphere greatly increases its cross sections for aerodynamic braking and energy dissipation. At a typical impact velocity of 22 km/s, the atmosphere absorbs more than half the kinetic energy of stony meteoroids with diameters, D(sub m), less than 220 m and iron meteoroids with D(sub m) less than 80 m. The corresponding diameter for comets with impact velocity 50 km/s is D(sub m) less than 1600 m. Most of the atmospheric energy dissipation occurs in a fraction of a scale height, so large meteors appear to 'explode' or 'flare' at the end of their visible paths. This dissipation of energy in the atmosphere protects the earth from direct impact damage (e.g., craters), but it produces a blast wave that can do considerable damage. The area of destruction around the impact point in which the over-pressure in the blast wave exceeds 4 lb/sq in = 2.8 x 10(exp 5) dynes/cu cm, which is enough to knock over trees and destroy buildings, increases rapidly from zero for chondritic meteoroids less than 56 m in diameter (15 megatons) to about 200 sq km for those 80 m in diameter (48 megatons); the probable diameter of the tunguska impactor of 1908 is about 80 m. Crater formation and earthquakes are not significant in land impacts by stony asteroids less than about 200 m in diameter because of the air protection. A tsunami is probably the most devastating type of damage for asteroids 200 m to 1 km in diameter. An impact by an asteroid this size anywhere in the Atlantic would devastate coastal areas on both sides of the ocean. An asteroid a few kilometers across would produce a tsunami that would reach the foothills of the Appalachian Mountains in the upper half of the East Coast of the United States. Most of Florida is protected from a tsunami by the gradual slope of the ocean off its coast, which causes most of the tsunami energy to be reflected back into the Atlantic. The atmosphere plume produced by asteroids with diameters exceeding

  6. The Physical Characterization of the Potentially-Hazardous Asteroid 2004 BL86: A Fragment of a Differentiated Asteroid

    OpenAIRE

    Reddy, Vishnu; Gary, Bruce L.; Sanchez, Juan A; Takir, Driss; Thomas, Cristina A.; Hardersen, Paul S.; Ogmen, Yenal; Benni, Paul; Thomas G Kaye; 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 tel...

  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. Capillary action in a crack on the surface of asteroids with an application to 433 Eros

    Science.gov (United States)

    Jiang, Yu; Baoyin, Hexi

    2016-08-01

    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 modeled 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 direction of the capillary is parallel to the vector from the center of mass to the surface position. The projected height in the capillary on the local surface of the asteroid seems to depend on the assumed direction of the capillary.

  9. 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 ...

  10. 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.

  11. Preliminary design of an asteroid hopping mission

    Science.gov (United States)

    Scheppa, Michael D.

    In 2010, NASA announced that its new vision is to support private space launch operations. It is anticipated that this new direction will create the need for new and innovative ideas that push the current boundaries of space exploration and contain the promise of substantial gain, both in research and capital. The purpose of the study is to plan and estimate the feasibility of a mission to visit a number of near Earth asteroids (NEAs). The mission would take place before the end of the 21st century, and would only use commercially available technology. Throughout the mission design process, while holding astronaut safety paramount, it was the goal to maximize the return while keeping the cost to a minimum. A mission of the nature would appeal to the private space industry because it could be easily adapted and set into motion. The mission design was divided into three main parts; mission timeline, vehicle design and power sources, with emphasis on nuclear and solar electric power, were investigated. The timeline and associated trajectories were initially selected using a numerical estimation and then optimized using Satellite Tool Kit (STK) 9.s's Design Explorer Optimizer [1]. Next, the spacecraft was design using commercially available parts that would support the mission requirements. The Variable Specific Impulse Magnetoplasma Rocket (VASIMR) was and instrumental piece in maximizing the number of NEAs visited. Once the spacecraft was designed, acceptable power supply options were investigated. The VASIMR VX-200 requires 200 kilowatts of power to maintain thrust. This creates the need for a substantial power supply that consists of either a nuclear reactor of massive solar arrays. STK 9.1's Design Explorer Optimizer was able to create a mission time line that allowed for the exploration of seven NEAs in under two years, while keeping the total mission DeltaV under 71 kilometers per second. Based on these initial findings, it is determined that a mission of this

  12. A photometric model for asteroid (21) Lutetia

    Science.gov (United States)

    Hasselmann, P.; Leyrat, C.; Fornasier, S.; Barucci, M.; Lazzaro, D.

    2014-07-01

    (21) Lutetia has been successfully observed (July 10, 2010) by the ESA Rosetta spacecraft during its journey toward the comet 67P/Churyumov-Gerasimenko (Sierks et al. 2011, Coradini et al. 2011). All the available data show intriguing characteristics with a complex surface composition interpretation (Barucci et al. 2012). The quite high mean density estimation (3.4±0.3, Pätzold et al. 2011) together with the unmatching density derived from the most probable surface compositions raise a hypothesis of (21) Lutetia having a metal core (Weiss et al 2012). The surface geology of (21) Lutetia is also highly complex with significant interactions between ancient and more recent structures (Thomas et al; 2012). The large craters and lineaments show that the object was heavily battered in the past, probably losing almost all of its crust in the process (Massironi et al 2012). If (21) Lutetia is a partially differentiated asteroid with an impact-stripped crust, a complete study of variegations might help in elucidating this event. Regions or strips of different albedo might indicate heavier- or lighter-battered surface histories. Albedo variations have been detected by Leyrat et al. (2012) in the visible wavelengths. In this work, we present a deeper analysis of the Lutetia photometric properties. For such analysis, a full set of pipelines was developed in the Python 2.7.6 language. Images obtained by the OSIRIS cameras, NAC and WAC, were used alongside the shape model provided by L. Jorda to derive for each facet the luminance angles and the correct I/F. The pipeline takes image pixels and matches with facets on different observational conditions. Facets are iteratively fitted by a phase function and a disk function. Several phase functions were tested as Akimov (1976), Kaasalainen (Kaasalainen et al. 2003), Schroder (Schroder et al; 2013) and polynomial and were implemented; for disk function, McEwen (1991), Akimov and Minnaert (1941) were used. The method can be also

  13. Circumpulsar Asteroids: Inferences from Nulling Statistics and High Energy Correlations

    Science.gov (United States)

    Shannon, Ryan; Cordes, J. M.

    2006-12-01

    We have proposed that some classes of radio pulsar variability are associated with the entry of neutral asteroidal material into the pulsar magnetosphere. The region surrounding neutron stars is polluted with supernova fall-back material, which collapses and condenses into an asteroid-bearing disk that is stable for millions of years. Over time, collisional and radiative processes cause the asteroids to migrate inward until they are heated to the point of ionization. For older and cooler pulsars, asteroids ionize within the large magnetospheres and inject a sufficient amount of charged particles to alter the electrodynamics of the gap regions and modulate emission processes. This extrinsic model unifies many observed phenomena of variability that occur on time scales that are disparate with the much shorter time scales associated with pulsars and their magnetospheres. One such type of variability is nulling, in which certain pulsars exhibit episodes of quiescence that for some objects may be as short as a few pulse periods, but, for others, is longer than days. Here, in the context of this model, we examine the nulling phenomenon. We analyze the relationship between in-falling material and the statistics of nulling. In addition, as motivation for further high energy observations, we consider the relationship between the nulling and other magnetospheric processes.

  14. Simulations of asteroid surfaces and interiors using geometric optics

    Science.gov (United States)

    Virkki, Anne; Muinonen, Karri; Penttilä, Antti

    2014-11-01

    We simulate electromagnetic scattering from a realistic model of an asteroid using an algorithm of geometric optics with Fresnelian reflection and refraction as well as diffuse scattering (Muinonen et al. 2009). The goal is to understand and constrain, which physical properties of the asteroid surface affect the radar parameters and how. The results show the simulated circular-polarization ratios and radar albedos compared to radar observations of asteroids.Two types of diffuse media will be studied: the first one is a uniform, internal diffuse medium inside a host body, and the second one is an external layer on the surface. The host body is large relative to the size of the diffuse scatterers and the wavelength (3-70 cm). Previously, we have utilized spheres and aggregates of spheres of different sizes as the diffuse scatterers. Now, we move on to more complex shapes, i.e., Gaussian random particles that mimic irregular boulders of 10-80 cm in size. In this study, we show how the type of the diffuse medium, including the mean free path or the optical thickness, affects the radar parameters. As for materials, we utilize the electric permittivities of solid and fractured rocks and ice. The applications of the study can be extended from asteroids also to comets and moons.References: Muinonen et al., Light scattering by Gaussian particles with internal inclusions and roughened surfaces using ray optics, JQSRT 110 (2009) 1628-1639.

  15. 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...

  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. 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".

  18. Comparative analysis of redirection methods for asteroid resource exploitation

    Science.gov (United States)

    Bazzocchi, Michael C. F.; Emami, M. Reza

    2016-03-01

    An in-depth analysis and systematic comparison of asteroid redirection methods are performed within a resource exploitation framework using different assessment mechanisms. Through this framework, mission objectives and constraints are specified for the redirection of an asteroid from a near-Earth orbit to a stable orbit in the Earth-Moon system. The paper provides a detailed investigation of five redirection methods, i.e., ion beam, tugboat, gravity tractor, laser sublimation, and mass ejector, with respect to their capabilities for a redirection mission. A set of mission level criteria are utilized to assess the performance of each redirection method, and the means of assigning attributes to each criterion is discussed in detail. In addition, the uncertainty in physical characteristics of the asteroid population is quantified through the use of Monte Carlo analysis. The Monte Carlo simulation provides insight into the performance robustness of the redirection methods with respect to the targeted asteroid range. Lastly, the attributes for each redirection method are aggregated using three different multicriteria assessment approaches, i.e., the Analytical Hierarchy Process, a utility-based approach, and a fuzzy aggregation mechanism. The results of each assessment approach as well as recommendations for further studies are discussed in detail.

  19. Collisional and dynamic evolution of dust from the asteroid belt

    Science.gov (United States)

    Gustafson, Bo A. S.; Gruen, Eberhard; Dermott, Stanley F.; Durda, Daniel D.

    1992-01-01

    The size and spatial distribution of collisional debris from main belt asteroids is modeled over a 10 million year period. The model dust and meteoroid particles spiral toward the Sun under the action of Poynting-Robertson drag and grind down as they collide with a static background of field particles.

  20. 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

  1. 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.

  2. Asteroid Redirect Robotic Mission: Robotic Boulder Capture Option Overview

    Science.gov (United States)

    Mazanek, Daniel D.; Merrill, Raymond G.; Belbin, Scott P.; Reeves, David M.; Earle, Kevin D.; Naasz, Bo J.; Abell, Paul A.

    2014-01-01

    The National Aeronautics and Space Administration (NASA) is currently studying an option for the Asteroid Redirect Robotic Mission (ARRM) that would capture a multi-ton boulder (typically 2-4 meters in size) from the surface of a large (is approximately 100+ meter) Near-Earth Asteroid (NEA) and return it to cislunar space for subsequent human and robotic exploration. This alternative mission approach, designated the Robotic Boulder Capture Option (Option B), has been investigated to determine the mission feasibility and identify potential differences from the initial ARRM concept of capturing an entire small NEA (4-10 meters in size), which has been designated the Small Asteroid Capture Option (Option A). Compared to the initial ARRM concept, Option B allows for centimeter-level characterization over an entire large NEA, the certainty of target NEA composition type, the ability to select the boulder that is captured, numerous opportunities for mission enhancements to support science objectives, additional experience operating at a low-gravity planetary body including extended surface contact, and the ability to demonstrate future planetary defense strategies on a hazardous-size NEA. Option B can leverage precursor missions and existing Agency capabilities to help ensure mission success by targeting wellcharacterized asteroids and can accommodate uncertain programmatic schedules by tailoring the return mass.

  3. 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...

  4. 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

  5. Asteroidal Space Weathering: The Major Role of FeS

    Science.gov (United States)

    Keller, L. P.; Rahman, Z.; Hiroi, T.; Sasaki, S.; Noble, S. K.; Horz, F.; Cintala, M. J.

    2013-01-01

    Space weathering (SW) effects on the lunar surface are reasonably well-understood from sample analyses, remote-sensing data, and experiments, yet our knowledge of asteroidal SW effects are far less constrained. While the same SW processes are operating on asteroids and the Moon, namely solar wind irradiation, impact vaporization and condensation, and impact melting, their relative rates and efficiencies are poorly known, as are their effects on such vastly different parent materials. Asteroidal SW models based on remote-sensing data and experiments are in wide disagreement over the dominant mechanisms involved and their kinetics. Lunar space weathering effects observed in UVVIS-NIR spectra result from surface- and volume-correlated nanophase Fe metal (npFe(sup 0)) particles. In the lunar case, it is the tiny vapor-deposited npFe(sup 0) that provides much of the spectral reddening, while the coarser (largely melt-derived) npFe(sup 0) produce lowered albedos. Nanophase FeS (npFeS) particles are expected to modify reflectance spectra in much the same way as npFe(sup 0) particles. Here we report the results of experiments designed to explore the efficiency of npFeS production via the main space weathering processes operating in the asteroid belt.

  6. 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.

  7. WISE Albedos for Tens of Thousands of Main Belt Asteroids

    NARCIS (Netherlands)

    Masiero, Joseph R.; Mainzer, A. K.; Bauer, J.; Cutri, R.; Dailey, J.; Delbo, M.; Grav, T.; McMillan, R. S.; Mueller, M.; Walker, R.; Wright, E.; WISE Science Team, [No Value

    2010-01-01

    Using thermal IR data from the Wide-field Infrared Survey Explorer (WISE) mission we have calculated diameters for tens of thousands of previously known Main Belt asteroids. Using archival optical observations we have also determined albedos for each object. We present our results from this investig

  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. 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

  10. Close Encounters of Asteroids and Comets to Planets

    Energy Technology Data Exchange (ETDEWEB)

    Hills, J.G.; Goda, M.P.; Solem, J.C.

    1999-07-09

    This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). The authors find by numerical simulations that the elongated-potato shape that is characteristic of Earth-crossing asteroids (ECAs) is likely the result of previous close tidal encounters with Earth. Some meteoroids graze the atmosphere of Earth before returning to space (at reduced speed). They used a spherical atmospheric model to study such grazers to find the condition under which they are captured into gravitationally bound orbits around Earth. They find that for about every thousand iron asteroids that hit the Earth, one is captured into a gravitational-bound orbit. Some fraction of these captured objects will have their orbits stabilized for many revolutions by tidal encounters with the Moon and the sun. They have also studied how the damage produced by such grazing and near-grazing asteroids differs from that produced by asteroids that hit Earth more directly.

  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. Bayesian Statistical Approach To Binary Asteroid Orbit Determination

    Science.gov (United States)

    Dmitrievna Kovalenko, Irina; Stoica, Radu S.

    2015-08-01

    Orbit determination from observations is one of the classical problems in celestial mechanics. Deriving the trajectory of binary asteroid with high precision is much more complicate than the trajectory of simple asteroid. Here we present a method of orbit determination based on the algorithm of Monte Carlo Markov Chain (MCMC). This method can be used for the preliminary orbit determination with relatively small number of observations, or for adjustment of orbit previously determined.The problem consists on determination of a conditional a posteriori probability density with given observations. Applying the Bayesian statistics, the a posteriori probability density of the binary asteroid orbital parameters is proportional to the a priori and likelihood probability densities. The likelihood function is related to the noise probability density and can be calculated from O-C deviations (Observed minus Calculated positions). The optionally used a priori probability density takes into account information about the population of discovered asteroids. The a priori probability density is used to constrain the phase space of possible orbits.As a MCMC method the Metropolis-Hastings algorithm has been applied, adding a globally convergent coefficient. The sequence of possible orbits derives through the sampling of each orbital parameter and acceptance criteria.The method allows to determine the phase space of every possible orbit considering each parameter. It also can be used to derive one orbit with the biggest probability density of orbital elements.

  13. 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

  14. 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.

  15. Thermally-driven destruction of asteroids at small perihelion distances

    Science.gov (United States)

    Granvik, Mikael; Morbidelli, Alessandro; Jedicke, Robert; Bolin, Bryce; Bottke, William F.; Beshore, Ed; Vokrouhlicky, David; Delbo, Marco; Michel, Patrick

    2015-11-01

    State-of-the-art models describing the orbits and absolute magnitudes of near-Earth objects (NEOs) predict that numerous NEOs should have been found on orbits with small perihelion distances, but few actual discoveries have been made. In addition, even though the NEO population in general is an even mix of low-albedo and high-albedo asteroids, the characterized NEOs near the Sun show a strong preference for high albedos. We have found, via a quantitative comparison of actual NEO detections and a new NEO model accounting for observational selection effects, that the deficit is produced by the super-catastrophic disruption of a substantial fraction of NEOs when they achieve perihelion distances of a few tens of solar radii. The destruction distance increases for small asteroids, and their temperatures during perihelion passages do not reach levels where evaporation could explain their disappearance. Although both bright and dark asteroids eventually disrupt, our work shows a preference for the elimination of low-albedo NEOs farther from the Sun, which explains the apparent excess of high-albedo NEOs and suggests that low-albedo asteroids break more easily as a result of thermal effects.

  16. 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.

  17. 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

  18. 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

  19. New Asteroid Models Derived From Combined Photometric Data

    Science.gov (United States)

    Durech, Josef; Kaasalainen, M.; Warner, B. D.

    2007-10-01

    The lightcurve inversion method is a powerful tool for deriving asteroid physical models (spin states and shapes) from their disk-integrated photometry. A typical input data set for a main belt asteroid consists of tens of lightcurves from at least three apparitions. As has been shown by Kaasalainen (2004, A&A 422, L39), it is also possible to use calibrated photometry sparse in time. This approach has been tested on synthetic data sets with accuracy and cadence expected for the Pan-STARRS project (Durech et al. 2006, EM&P 97, 179). At present, new accurate photometric data are not yet available. However, it is possible to combine sparse photometry obtained during astrometric observations with a few dense lightcurves and in some cases derive new asteroid models from such combined data sets. We present about twenty new asteroid models derived from combined data sets. Dense lightcurves (the majority of them from the Uppsala Asteroid Photometric Catalogue) were combined with sparse photometric data from astrometric observations carried out at the US Naval Observatory in Flagstaff. The accuracy of the sparse photometry is about 0.08-0.1 mag, which is in some cases enough to derive a unique model. We have performed many tests that confirm credibility of our results and show typical uncertainties in the shape/pole/period determination. Although the shape models are coarse and may change with new data, the error in the pole direction is usually not higher than 20 deg of arc. In some cases, when the pole direction is not unique, the only physical parameters that can be determined are the rotation period and the ecliptic latitude of the spin axis.

  20. On the oldest asteroid families in the main belt

    Science.gov (United States)

    Carruba, V.; Nesvorný, D.; Aljbaae, S.; Domingos, R. C.; Huaman, M.

    2016-06-01

    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 Yarkovsky-O'Keefe-Radzievskii-Paddack (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 time-scales 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 families in the asteroid main belt. Our results show that none of the seven studied families has a nominally mean estimated age older than 2.7 Gyr, assuming standard values for the parameters describing the strength of the Yarkovsky force. Most `paleo-families' that formed between 2.7 and 3.8 Gyr would be characterized by a very shallow size-frequency distribution, and could be recognizable only if located in a dynamically less active region (such as that of the Koronis family). V-type asteroids in the central main belt could be compatible with a formation from a paleo-Eunomia family.

  1. 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.

  2. Petrologic evidence for collisional heating of chondritic asteroids

    Science.gov (United States)

    Rubin, Alan E.

    1995-01-01

    The identification of the mechanism(s) responsible for heating asteroids is among the major problems in planetary science. Because of difficulties with models of electromagnetic induction and the decay of short-lived radionuclides, it is worthwhile to evaluate the evidence for collisional heating. New evidence for localized impact heating comes from the high proportion of relict type-6 material among impact-melt-bearing ordinary chondrites (OC). This relict material was probably metamorphosed by residual heat within large craters. Olivine aggregates composed of faceted crystals with 120 deg triple junctions occur within the melted regions of the Chico and Rose City OC melt rocks; the olivine aggregates formed from shocked, mosaicized olivine grains that underwent contact metamorphism. Large-scale collisional heating is supoorted by the correlation in OC between petrologic type and shock stage; no other heating mechanism can readily account for this correlation. The occurrence of impact-melt-rock clasts in OC that have been metamorphosed along with their whole rocks indicates that some impact events preceded or accompanied thermal metamorphism. Such impacts events, occurring during or shortly after accretion, are probably responsible for substantially melting approximately 0.5% of OC. These events must have heated a larger percentage of OC to subsolidus temperatures sufficient to have caused significant metamorphism. If collisional heating is viable, then OC parent asteroids must have been large; large OC asteroids in the main belt may include those of the S(IV) spectral subtype. Collisional heating is inconsistent with layered ('onion-shell') structures in OC asteroids (wherein the degree of metamorphism increases with depth), but the evidence for such structures is weak. It seems likely that collisional heating played an important role in metamorphosing chondritic asteroids.

  3. An Overview of NASA's Asteroid Redirect Mission (ARM) Concept

    Science.gov (United States)

    Abell, P. A.; Mazanek, D. D.; Reeves, D. M.; Chodas, P. W.; Gates, M. M.; Johnson, L. N.; Ticker, R. L.

    2016-01-01

    The National Aeronautics and Space Administration (NASA) is developing the Asteroid Redirect Mission (ARM) as a capability demonstration for future human exploration, including use of high-power solar electric propulsion, which allows for the efficient movement of large masses through deep space. The ARM will also demonstrate the capability to conduct proximity operations with natural space objects and crewed operations beyond the security of quick Earth return. The Asteroid Redirect Robotic Mission (ARRM), currently in formulation, will visit a large near-Earth asteroid (NEA), collect a multi-ton boulder from its surface, conduct a demonstration of a slow push planetary defense technique, and redirect the multi-ton boulder into a stable orbit around the Moon. Once returned to cislunar space in the mid-2020s, astronauts aboard an Orion spacecraft will dock with the robotic vehicle to explore the boulder and return samples to Earth. The ARM is part of NASA's plan to advance technologies, capabilities, and spaceflight experience needed for a human mission to the Martian system in the 2030s. The ARM and subsequent availability of the asteroidal material in cis-lunar space, provide significant opportunities to advance our knowledge of small bodies in the synergistic areas of science, planetary defense, and in-situ resource utilization (ISRU). NASA established the Formulation Assessment and Support Team (FAST), comprised of scientists, engineers, and technologists, which supported ARRM mission requirements formulation, answered specific questions concerning potential target asteroid physical properties, and produced a publically available report. The ARM Investigation Team is being organized to support ARM implementation and execution. NASA is also open to collaboration with its international partners and welcomes further discussions. An overview of the ARM robotic and crewed segments, including mission requirements, NEA targets, and mission operations, and a discussion

  4. 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

  5. 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...

  6. 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.

  7. Two cubesat mission to study the Didymos asteroid system

    Science.gov (United States)

    Wahlund, J.-E.; Vinterhav, E.; Trigo-Rodríguez, J. M.; Hallmann, M.; Barabash, S.; Ivchenko, N.

    2015-10-01

    Among the growing interest about asteroid impact hazard mitigation in our community the Asteroid Impact & Deflection Assessment (AIDA) mission will be the first space experiment to use a kinetic impactor to demonstrate its capability as reliable deflection system [1]. As a part of the AIDA mission, we have proposed a set of two three-axis stabilized 3U CubeSats (with up to 5 science sensors) to simultaneously rendezvous at close range (continued science operation. The science sensors consist of a dual fluxgate magnetometer (MAG), one miniaturized volatile composition analyser (VCA), a narrow angle camera (NAC) and a Video Emission Spectrometer (VES) with a diffraction grating for allowing a sequential chemical study of the emission spectra associated with the impact flare and the expanding plume. Consequently, the different envisioned instruments onboard the CubeSats can provide significant insight into the complex response of asteroid materials during impacts that has been theoretically studied using different techniques [2]. The two CubeSats will remain stowed in CubeSat dispensers aboard the main AIM spacecraft. They will be deployed and commissioned before the AIM impactor reaches the secondary and record the impact event from a closer vantage point than the main spacecraft. The two CubeSats are equipped with relative navigation systems capable of estimating the spacecraft position relative to the asteroids and propulsion system that allow them to operate close to the asteroid bodies. The two CubeSats will rely on mapping data relayed via the AIM main spacecraft but operate autonomously and individually based on schedules and navigation maps uploaded from ground. AIDA's target is the binary Apollo asteroid 65803 Didymos that is also catalogued as Potentially Hazardous Asteroid (PHA) because it experiences close approaches to Earth. Didymos' primary has a diameter of ˜800 meters and the secondary is ˜150 m across. Both bodies are separated about 1.1 km [3

  8. 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...

  9. 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

  10. 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...

  11. The Strength and Detectability of the YORP Effect in Near-Earth Asteroids: A Statistical Approach

    CERN Document Server

    Rozitis, Ben

    2013-01-01

    In addition to collisions and gravitational forces, it is now becoming widely acknowledged that photon recoil forces and torques from the asymmetric reflection and thermal re-radiation of sunlight are primary mechanisms that govern the rotational evolution of an asteroid. The Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) effect causes changes in the rotation rate and pole direction of an irregularly shaped asteroid. We present a simple Monte Carlo method to estimate the range of YORP-rotational-accelerations acting on a near-Earth asteroid (NEA) without knowledge of its detailed shape, and to estimate its detectability using light-curve observations. The method requires knowledge of an asteroid's orbital properties and size, and assumes that the future observational circumstances of an asteroid have already been thought through. It is verified by application to the observational circumstances of the seven YORP-investigated asteroids, and is then applied to 540 NEAs with NEOWISE and/or other diameter measuremen...

  12. Physical and orbital properties of the Trojan asteroids

    CERN Document Server

    Melita, M D; Jones, D C; Williams, I P

    2008-01-01

    All the Trojan asteroids orbit about the Sun at roughly the same heliocentric distance as Jupiter. Differences in the observed visible reflection spectra range from neutral to red, with no ultra-red objects found so far. Given that the Trojan asteroids are collisionally evolved, a certain degree of variability is expected. Additionally, cosmic radiation and sublimation are important factors in modifying icy surfaces even at those large heliocentric distances. We search for correlations between physical and dynamical properties, we explore relationships between the following four quantities; the normalised visible reflectivity indexes ($S'$), the absolute magnitudes, the observed albedos and the orbital stability of the Trojans. We present here visible spectroscopic spectra of 25 Trojans. This new data increase by a factor of about 5 the size of the sample of visible spectra of Jupiter Trojans on unstable orbits. The observations were carried out at the ESO-NTT telescope (3.5m) at La Silla, Chile, the ING-WHT ...

  13. 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...

  14. Asteroid orbits with Gaia using random-walk statistical ranging

    Science.gov (United States)

    Muinonen, Karri; Fedorets, Grigori; Pentikäinen, Hanna; Pieniluoma, Tuomo; Oszkiewicz, Dagmara; Granvik, Mikael; Virtanen, Jenni; Tanga, Paolo; Mignard, François; Berthier, Jérôme; Dell`Oro, Aldo; Carry, Benoit; Thuillot, William

    2016-04-01

    We describe statistical inverse methods for the computation of initial asteroid orbits within the data processing and analysis pipeline of the ESA Gaia space mission. Given small numbers of astrometric observations across short time intervals, we put forward a random-walk ranging method, in which the orbital-element phase space is uniformly sampled, up to a limiting χ2-value, with the help of the Markov-chain Monte Carlo technique (MCMC). The sample orbits obtain weights from the a posteriori probability density value and the MCMC rejection rate. For the first time, we apply the method to Gaia astrometry of asteroids. The results are nominal in that the method provides realistic estimates for the orbital uncertainties and meets the efficiency requirements for the daily, short-term processing of unknown objects.

  15. 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.

  16. The Formation of the Wide Asynchronous Binary Asteroid Population

    CERN Document Server

    Jacobson, Seth A; McMahon, Jay

    2013-01-01

    We propose and analyze a new mechanism for the formation of the wide asynchronous binary population. These binary asteroids have wide semi-major axes relative to most near-Earth and Main Belt asteroid systems. Confirmed members have rapidly rotating primaries and satellites that are not tidally locked. Previously suggested formation mechanisms from impact ejecta, planetary flybys and directly from rotational fission events cannot satisfy all of the observations. The newly hypothesized mechanism works as follows: (i) these systems are formed from rotational fission, (ii) their satellites are tidally locked, (iii) their orbits are expanded by the BYORP effect, (iv) their satellites de-synchronize due to the adiabatic invariance between the libration of the secondary and the mutual orbit, and (v) the secondary avoids resynchronization due to the the YORP effect. This seemingly complex chain of events is a natural pathway for binaries with satellites that have particular shapes, which define the BYORP effect torq...

  17. The distribution and source of boulders on asteroid 4179 Toutatis

    Science.gov (United States)

    Jiang, Yun; Ji, Jianghui; Huang, Jiangchuan; Marchi, Simone; Li, Yuan; Ip, Wing-Huen

    2016-01-01

    Boulders are ubiquitous on the surfaces of asteroids and their spatial and size distributions provide information for the geological evolution and collisional history of parent bodies. We identify more than 200 boulders on near-Earth asteroid 4179 Toutatis based on images obtained by Chang'e-2 flyby. The cumulative boulder size frequency distribution (SFD) gives a power-index of -4.4 +/- 0.1, which is clearly steeper than those of boulders on Itokawa and Eros, indicating much high degree of fragmentation. Correlation analyses with craters suggest that most boulders cannot solely be produced as products of cratering, but are probably survived fragments from the parent body of Toutatis, accreted after its breakup. Similar to Itokawa, Toutatis probably has a rubble-pile structure, but owns a different preservation state of boulders.

  18. 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.

  19. Dynamical study of the Atira group of asteroids

    Science.gov (United States)

    Ribeiro, A. O.; Roig, F.; De Prá, M. N.; Carvano, J. M.; DeSouza, S. R.

    2016-06-01

    We study the dynamics of the group of Atira asteroids, characterized by aphelion distance Q Earth. Here, we construct dynamical maps of the region between 0.2 and 0.98 au using a simple chaos indicator, the mean standard deviation in semimajor axis, and also analyse the behaviour of the real Atira orbits by means of the diffusion coefficient in semimajor axis. Our results indicate that Atira asteroids are located in the most unstable regions of the inner Solar system, and their stability is determined by close encounters and collisions with Mercury, Venus, and the Earth. A fraction of the known Atiras may represent a potential threat to the Earth over a few 105 yr of evolution. We found two islands of low-eccentricity stable orbits that might harbour a long-lasting sub-population of Atiras not yet observed.

  20. 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.

  1. A simple model to determine chaotic motions around asteroids

    Directory of Open Access Journals (Sweden)

    A. Elipe

    2006-01-01

    Full Text Available Es conocido que el movimiento tridimensional en las proximidades del asteroide (433 Eros es caótico para un amplio abanico de inclinaciones. La principal característica de este asteroide es su forma alargada, lo que hace que los procedimientos habituales de desarrollar el potencial en armónicos esféricos no tenga mucha utilidad. Por tal razón, consideramos un modelo simple que aproxime su forma alargada; en concreto, tomamos una varilla alargada y en rotación. De este modo se puede obtener el potencial de forma cerrada, sin necesidad de desarrollos. Con este modelo tan simple y mediante el cálculo de familias de orbitas periódicas, podemos obtener una explicación para la mayor a de las características dinámicas previamente halladas para el movimiento orbital alrededor de Eros.

  2. "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

  3. Near-Earth Asteroid Retrieval Mission (ARM) study

    OpenAIRE

    Brophy, John R.; Muirhead, Brian

    2013-01-01

    The Asteroid Redirect Mission (ARM) concept brings together the capabilities of the science, technology, and the human exploration communities on a grand challenge combining robotic and human space exploration beyond low Earth orbit. This paper addresses the key aspects of this concept and the options studied to assess its technical feasibility. Included are evaluations of the expected number of potential targets, their expected discovery rate, the necessity to adequately chara...

  4. 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.

  5. 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.

  6. 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)

  7. Asteroid Discovery and Characterization with the Large Synoptic Survey Telescope

    Science.gov (United States)

    Jones, R. Lynne; Jurić, Mario; Ivezić, Željko

    2016-01-01

    The Large Synoptic Survey Telescope (LSST) will be a ground-based, optical, all-sky, rapid cadence survey project with tremendous potential for discovering and characterizing asteroids. With LSST's large 6.5m diameter primary mirror, a wide 9.6 square degree field of view 3.2 Gigapixel camera, and rapid observational cadence, LSST will discover more than 5 million asteroids over its ten year survey lifetime. With a single visit limiting magnitude of 24.5 in r band, LSST will be able to detect asteroids in the Main Belt down to sub-kilometer sizes. The current strawman for the LSST survey strategy is to obtain two visits (each `visit' being a pair of back-to-back 15s exposures) per field, separated by about 30 minutes, covering the entire visible sky every 3-4 days throughout the observing season, for ten years. The catalogs generated by LSST will increase the known number of small bodies in the Solar System by a factor of 10-100 times, among all populations. The median number of observations for Main Belt asteroids will be on the order of 200-300, with Near Earth Objects receiving a median of 90 observations. These observations will be spread among ugrizy bandpasses, providing photometric colors and allow sparse lightcurve inversion to determine rotation periods, spin axes, and shape information. These catalogs will be created using automated detection software, the LSST Moving Object Processing System (MOPS), that will take advantage of the carefully characterized LSST optical system, cosmetically clean camera, and recent improvements in difference imaging. Tests with the prototype MOPS software indicate that linking detections (and thus `discovery') will be possible at LSST depths with our working model for the survey strategy, but evaluation of MOPS and improvements in the survey strategy will continue. All data products and software created by LSST will be publicly available.

  8. Asteroid 951 Gaspra Near Infrared Mapping Spectrometer Radiance Data

    Science.gov (United States)

    Granahan, J. C., Jr.

    2015-12-01

    Five radiance spectra of asteroid 951 Gaspra have been archived in the Small Bodies Node of the NASA Planetary Data System [Granahan, 2014]. The radiance spectra were created from uncalibrated Galileo spacecraft Near Infrared Mapping Spectrometer files archived in the Imaging Node of the NASA Planetary Data System. The NASA Galileo spacecraft observed asteroid 951 Gaspra on October 29, 1991 with the Near Infrared Mapping Spectrometer (NIMS) at wavelengths ranging from 0.7 - 5.2 micrometers [Carlson et al., 1992]. The five radiance spectra consist of two 17, two 100, and one 329 spectral channel data sets. They record data that was acquired by NIMS at ranges between 27232.6 to 14723.8 kilometers from asteroid 951 Gaspra. The uncalibrated NIMS data were converted into radiance spectra using calibration coefficients obtained during the Galileo mission's first Earth encounter on December 8, 1990. The archived radiance spectral data is located at the URL (Universal Record Locator): http://sbn.psi.edu/pds/resource/gaspraspec.html and contains radiance, solar, incidence over flux, and data documentation. This archived data set contains a variety of spectral signatures. These signatures include absorptions near 1.0, 2.0, 2.8, 3.4, and 4.5 micrometers. The 1.0 and 2.0 micrometer features are indicators of olivine and pyroxene on the asteroid surface. The 2.8 micrometer feature has a shape similar to the combined spectra of multiple iron bearing phyllosilicates. The 3.4 micrometer feature is in the same location as absorptions created by a carbon-hydrogen bond. The 4.5 micrometer feature, present only in the 329 channel data set, corresponds in position to absorptions detected in sulfate minerals. Carlson, R. W., et al. (1992) Bull. of the A.A.S., 24, 932. Granahan, J. C. (2014), GO-A-NIMS-3-GASPRASPEC-V1.0, NASA Planetary Data System.

  9. The recovery of asteroid 2008 TC[subscript 3

    Energy Technology Data Exchange (ETDEWEB)

    Shaddad, Muawia H.; Jenniskens, Peter; Numan, Diyaa; Kudoda, Ayman M.; Elsir, Saadia; Riyad, Ihab F.; Ali, Awad Elkareem; Alameen, Mohammed; Alameen, Nada M.; Eid, Omer; Osman, Ahmed T.; AbuBaker, Mohamed I.; Yousif, Mohamed; Chesley, Steven R.; Chodas, Paul W.; Albers, Jim; Edwards, Wayne N.; Brown, Peter G.; Kuiper, Jacob; Friedrich, Jon M. (CIT); (Juba); (RNMI-Netherlands); (Khartoum); (UWO); (SETI); (Fordham)

    2011-09-06

    On October 7, 2008, asteroid 2008 TC{sub 3} impacted Earth and fragmented at 37 km altitude above the Nubian Desert in northern Sudan. The area surrounding the asteroid's approach path was searched, resulting in the first recovery of meteorites from an asteroid observed in space. This was also the first recovery of remains from a fragile 'cometary' PE = IIIa/b type fireball. In subsequent searches, over 600 mostly small 0.2-379 g meteorites (named 'Almahata Sitta') with a total mass 10.7 kg were recovered from a 30 x 7 km area. Meteorites fell along the track at 1.3 kg km{sup -1}, nearly independent of mass between 1 and 400 g, with a total fallen mass of 39 {+-} 6 kg. The strewn field was shifted nearly 1.8 km south from the calculated approach path. The influence of winds on the distribution of the meteorites, and on the motion of the dust train, is investigated. The majority of meteorites are ureilites with densities around 2.8 g cm{sup -3}, some of an anomalous (porous, high in carbon) polymict ureilite variety with densities as low as 1.5 g cm{sup -3}. In addition, an estimated 20-30% (in mass) of recovered meteorites were ordinary, enstatite, and carbonaceous chondrites. Their fresh look and matching distribution of fragments in the strewn field imply that they were part of 2008 TC{sub 3}. For that reason, they are all referred to as 'Almahata Sitta.' No ureilite meteorites were found that still held foreign clasts, suggesting that the asteroid's clasts were only loosely bound.

  10. 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.

  11. 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.

  12. Photometric analysis of asteroids and comets from space observations

    OpenAIRE

    La Forgia, Fiorangela

    2014-01-01

    The European space mission Rosetta, during its still ongoing journey to the comet 67P/Churyumov-Gerasimenko, on 10 July 2010 made an intermediate stop flying close to the asteroid 21 Lutetia at a distance of less than 3200 km and observed it from a varying observing point, otherwise inaccessible from Earth. Less than four months later, on 4 November 2010, the EPOXI mission, extension of the NASA Deep Impact mission, offered another unexpected opportunity approaching the small hyperactive Jupi...

  13. Method for improved extraction of DNA from Nocardia asteroides.

    OpenAIRE

    Loeffelholz, M. J.; Scholl, D R

    1989-01-01

    In a variation of standard DNA extraction methods, Nocardia asteroides was repeatedly exposed to sodium dodecyl sulfate at 60 degrees C for 30 min; each extraction was followed by centrifugation, removal of the nucleic acid-rich supernatant, and suspension of the cell pellet in fresh sodium dodecyl sulfate. The pooled supernatants contained a substantially higher amount of DNA than the first supernatant alone. The possible implications of this procedure on the development of DNA probes are di...

  14. Is the reddening of asteroids still a dilemma?

    Science.gov (United States)

    Moretti, P. F.:; Maras, A.; Folco, L.

    The association of the most abundant population of meteorites the ordinary chondrites and their parent bodies through the comparison of their reflected spectra has been a long debate In fact many of the asteroids show reddened spectra when observed in the visible and near-infrared range Gaffey 1976 Cloutis et al 1990 This reddening first observed in lunar mature soils has been demonstrated to be caused by the presence of metallic nano-particles Pieters et al 2000 Noble et al 2004 Though laboratory experiments reproduced the formation of such npFe as due to the vaporization of Fe-bearing silicates caused by the bombardment of micro meteoroids Sasaki et al 2001 the close-up observations of S-type asteroids obtained by the NEAR mission proposed a new mystery to be solved In fact if the continuous exposition to the space conditions should in principle darken and redden the surface of asteroids the slopes of the Psyche crater on Eros shows redder but brighter spectra when compared to the proposed associated meteorites Clark et al 2001 This result asked for a mechanism capable to redden much more than darken Very recently an alternative process has been suggested for surface alteration of airless bodies In fact metallic nano-particles have been demonstrated to be formed in Fe-Ni regions of ordinary chondrites where shock-induced transformation occurred Moretti et al 2005 Even if this last mechanism is capable to redden almost instantaneously localized regions on asteroids surfaces the distribution of the spectral slopes

  15. Near-Earth Asteroid Tracking (NEAT): First Year Results

    Science.gov (United States)

    Helin, E. F.; Rabinowitz, D. L.; Pravdo, S. H.; Lawrence, K. J.

    1997-07-01

    The successful detection of Near-Earth Asteroids (NEAs) has been demonstrated by the Near-Earth Asteroid Tracking (NEAT) program at the Jet Propulsion Laboratory during its first year of operation. The NEAT CCD camera system is installed on the U. S. Air Force 1-m GEODSS telescope in Maui. Using state-of-the-art software and hardware, the system initiates nightly transmitted observing script from JPL, moves the telescopes for successive exposures of the selected fields, detects moving objects as faint as V=20.5 in 40 s exposures, determines their astrometric positions, and downloads the data for review at JPL in the morning. The NEAT system is detecting NEAs larger than 200m, comets, and other unique objects at a rate competitive with current operating systems, and bright enough for important physical studies on moderate-sized telescopes. NEAT has detected over 10,000 asteroids over a wide range of magnitudes, demonstrating the excellent capability of the NEAT system. Fifty-five percent of the detections are new objects and over 900 of them have been followed on a second night to receive designation from the Minor Planet Center. 14 NEAs (9 Amors, 4 Apollos, and 1 Aten) have been discovered since March 1996. Also, 2 long period comets and 1996 PW, an asteroidal object with an orbit of a long-period comet, with an eccentricity of 0.992 and orbital period of 5900 years. Program discoveries will be reviewed along with analysis of results pertaining to the discovery efficiency, distribution on the sky, range of orbits and magnitudes. Related abstract: Lawrence, K., et al., 1997 DPS

  16. Asteroids in the Inner Solar System II - Observable Properties

    OpenAIRE

    Evans, N. W.; Tabachnik, S. A.

    2000-01-01

    This paper presents synthetic observations of long-lived, coorbiting asteroids of Mercury, Venus, the Earth and Mars. Our sample is constructed by taking the limiting semimajor axes, differential longitudes and inclinations for long-lived stability provided by simulations. The intervals are randomly populated with values to create initial conditions. These orbits are re-simulated to check that they are stable and then re-sampled every 2.5 years for 1 million years. The Mercurian sample contai...

  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. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. Sensitivity to Uncertainty in Asteroid Impact Risk Assessment

    Science.gov (United States)

    Mathias, D.; Wheeler, L.; Prabhu, D. K.; Aftosmis, M.; Dotson, J.; Robertson, D. K.

    2015-12-01

    The Engineering Risk Assessment (ERA) team at NASA Ames Research Center is developing a physics-based impact risk model for probabilistically assessing threats from potential asteroid impacts on Earth. The model integrates probabilistic sampling of asteroid parameter ranges with physics-based analyses of entry, breakup, and impact to estimate damage areas and casualties from various impact scenarios. Assessing these threats is a highly coupled, dynamic problem involving significant uncertainties in the range of expected asteroid characteristics, how those characteristics may affect the level of damage, and the fidelity of various modeling approaches and assumptions. The presented model is used to explore the sensitivity of impact risk estimates to these uncertainties in order to gain insight into what additional data or modeling refinements are most important for producing effective, meaningful risk assessments. In the extreme cases of very small or very large impacts, the results are generally insensitive to many of the characterization and modeling assumptions. However, the nature of the sensitivity can change across moderate-sized impacts. Results will focus on the value of additional information in this critical, mid-size range, and how this additional data can support more robust mitigation decisions.

  4. Nature of the Kirkwood gaps in the asteroid belt

    Science.gov (United States)

    Dermott, S. F.; Murray, C. D.

    1983-01-01

    It is demonstrated that the Kirkwood gaps are not merely regions of low asteroidal number density, but are regions in a-e-sin 1/2 I space where libration of some argument is possible. It is argued that neither the statistical nor the cosmogonic hypothesis of gap formation can account for these new observations. It is shown that the present distribution of asteroidal semimajor axes can be used to deduce the present semimajor axis of Jupiter to an accuracy of one part in five thousand. Thus, there has been very little change in the orbital period of Jupiter since the time of formation of the present gaps. This observation eliminates the possibility that the observed gaps were formed by resonance sweeping at the time of the dispersal of the accretion disk. It is concluded that the gaps have been formed by the gravitational action of Jupiter on individual asteroids and that gap formation has probably continued throughout the lifetime of the solar system.

  5. 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...

  6. Footprints of the YORP effect in asteroid families

    Science.gov (United States)

    Paolicchi, Paolo; Knežević, Zoran

    2016-08-01

    The YORP effect affects not only the rotation rate, but also the spin orientation of asteroids. For this reason, due to Yarkovsky effect, it influences also the evolution of the semimajor axis with time. In asteroid dynamical families, the combined outcome can be a depletion of objects in the central part of the family, shown by the absolute magnitude vs. semimajor axis so-called V-plot. A reclassification of asteroid families, extended to a very large database of proper elements, has recently been performed by Milani et al. [2014] (Icarus, 239, 46-73). Only some of the related V-plots, used to estimate the age of several families, exhibit the depletion predicted above. In this paper we discuss the problem, introducing the concept of the YORP-eye and a general method of analysis. We show that the effect may sometimes be located in the low H tail, and thus difficult to detect. Moreover, it may be hindered by several anomalous physical properties of the family (asymmetry, cratering origin, multiple collisions history and so on). With a new method of analysis, we identify the footprints of the effect for most of the analysed families, obtaining also an independent estimate of the age of the family. In spite of the uncertainties, we obtain a very good agreement between these ages and those estimated on the basis of the slope of the V-plot: a result which supports both methods and the underlying physics.

  7. 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

  8. 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 ...

  9. 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.

  10. 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...

  11. Asteroid breakup linked to the Great Ordovician Biodiversification Event

    Science.gov (United States)

    Schmitz, Birger; Harper, David A. T.; Peucker-Ehrenbrink, Bernhard; Stouge, Svend; Alwmark, Carl; Cronholm, Anders; Bergström, Stig M.; Tassinari, Mario; Xiaofeng, Wang

    2008-01-01

    The rise and diversification of shelled invertebrate life in the early Phanerozoic eon occurred in two major stages. During the first stage (termed as the Cambrian explosion), a large number of new phyla appeared over a short time interval ~540Myrago. Biodiversity at the family, genus and species level, however, remained low until the second stage marked by the Great Ordovician Biodiversification Event in the Middle Ordovician period. Although this event represents the most intense phase of species radiation during the Palaeozoic era and led to irreversible changes in the biological make-up of Earth's seafloors, the causes of this event remain elusive. Here, we show that the onset of the major phase of biodiversification ~470Myrago coincides with the disruption in the asteroid belt of the L-chondrite parent body-the largest documented asteroid breakup event during the past few billion years. The precise coincidence between these two events is established by bed-by-bed records of extraterrestrial chromite, osmium isotopes and invertebrate fossils in Middle Ordovician strata in Baltoscandia and China. We argue that frequent impacts on Earth of kilometre-sized asteroids-supported by abundant Middle Ordovician fossil meteorites and impact craters-accelerated the biodiversification process.

  12. On the original distribution of the asteroids. II. Do stable orbits exist between Jupiter and Saturn?

    International Nuclear Information System (INIS)

    Prompted by the recent indication by Wisdom (1987) that orbits may appear stable for very long periods and then suddenly become chaotic, an earlier integration of asteroidlike orbits between Jupiter and Saturn in which most of the asteroids had close encounters with these planets and were removed is extended nearly 2000 times longer. Where two bands, centered on 1.35 and 1.45 Jovian distances, harbored asteroids before, all the asteroids are presently removed. Asteroids are found to be removed by Saturn-orbit crossings 5 times more frequently than by Jupiter-orbit crossing. 13 refs

  13. 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).

  14. 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).

  15. The Lockne - Målingen doublet impacts, the result of a binary asteroid from the 470 Ma Main Asteroid Belt event

    Science.gov (United States)

    Sturkell, E. C.; Ormo, J.; Alwmark, C.; Melosh, H., IV

    2015-12-01

    Approximately 470 million years ago one of the largest cosmic catastrophes occurred in our solar system since the accretion of the planets. A 200-km large asteroid was disrupted by a collision in the Main Asteroid Belt (MAB), which spawned fragments into Earth crossing orbits. This had tremendous consequences for the meteorite production and cratering rate during several millions of years following the event. The 7.5-km wide Lockne crater, central Sweden, is known to be a member of this family. The 600 m large Lockne asteroid was a binary and had a companion in space by a smaller 150 m satellite. The recent discovery of the nearby, 0.7-km diameter, synchronous Målingen crater suggests it to form a doublet impact structure together with the larger Lockne crater, and as we will show here, most likely by a binary, 'rubble pile' asteroid. Despite observational evidence that about 16% of the Near Earth Asteroids (NEA's) are binary, only a handful of the approximately 188 known craters on Earth have been suggested as potential doublets. The stratigraphic and geographic relationship with Lockne suggests the Lockne and Målingen craters to be the first described doublet impact structure by a binary asteroid into a marine-target setting. In addition, the precise dating of the Lockne-Målingen impact in relation to the MAB breakup event provides a hands-on reference for studies of the formation of binaries from asteroid breakup events.

  16. 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

  17. 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

  18. 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...

  19. 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...

  20. ESO Views of Earth-Approaching Asteroid Toutatis

    Science.gov (United States)

    2004-09-01

    Today, September 29, 2004, is undisputedly the Day of Toutatis, the famous "doomsday" asteroid. Not since the year 1353 did this impressive "space rock" pass so close by the Earth as it does today. Visible as a fast-moving faint point of light in the southern skies, it approaches the Earth to within 1,550,000 km, or just four times the distance of the Moon. Closely watched by astronomers since its discovery in January 1989, this asteroid has been found to move in an orbit that brings it close to the Earth at regular intervals, about once every four years. This happened in 1992, 1996, 2000 and now again in 2004. Radar observations during these passages have shown that Toutatis has an elongated shape, measuring about 4.6 x 2.4 x 1.9 km. It tumbles slowly through space, with a rotation period of 5.4 days. The above images of Toutatis were taken with the ESO Very Large Telescope (during a technical test) in the evening of September 28. They were obtained just over 12 hours before the closest approach that happens today at about 15:40 hrs Central European Summer Time (CEST), or 13:40 hrs Universal Time (UT). At the time of these observations, Toutatis was about 1,640,000 km from the Earth, moving with a speed of about 11 km/sec relative to our planet. They show the asteroid as a fast-moving object of magnitude 10, about 40 times fainter than what can be perceived with the unaided, dark-adapted eye. They also prove that Toutatis is right on track, following exactly the predicted trajectory in space and passing the Earth at a safe distance, as foreseen. Detailed calculations, taking into account all available observations of this celestial body, have shown that although Toutatis passes regularly near the Earth, today's passage is the closest one for quite some time, at least until the year 2562. The ESO observations, obtained at a moment when Toutatis was very close to the Earth, will help to further refine the orbital calculations. The "parallax effect" demonstrated! ESO

  1. Light-Curve Survey of Jupiter Trojan Asteroids

    Science.gov (United States)

    Duffard, R.; Melita, M.; Ortiz, J. L.; Licandro, J.; Williams, I. P.; Jones, D.

    2008-09-01

    Trojan asteroids are an interesting population of minor bodies due to their dynamical characteristics, their physical properties and that they are relatively isolated located at the snow-line The main hypotheses about the origin of the Jupiter Trojans assumed that they formed either during the final stages of the planetary formation (Marzari & Scholl 1998), or during the epoch of planetary migration (Morbidelli et al. 2005), in any case more than 3.8 Gy. ago. The dynamical configuration kept the Trojans isolated from the asteroid Main Belt throughout the history of the Solar System. In spite of eventual interactions with other populations of minor bodies like the Hildas, the Jupiter family comets, and the Centaurs, their collisional evolution has been dictated mostly by the intrapopulation collisions (Marzari et al. 1996, 1997). Therefore, the Jupiter Trojans may be considered primordial bodies, whose dynamical and physical properties can provide important clues about the environment of planetary formation. The available sample of Jupiter Trojans light-curves is small and mainly restricted to the largest objects. According to the MPC-website (updated last in March 2006), the present sample of rotation periods and light-curve-amplitudes of the Jupiter Trojan asteroids is composed by 25 objects with some information about their periods and by 10 of them with only an amplitude estimation. A survey of contact binary Trojan asteroids has been done by Mann et al. 2007, where they have recorded more than 100 amplitudes from sparse-sampled light-curves and very-wellresolved rotational periods. More than 2000 Trojan asteroids have been discovered up to date, so, there is an urgent need to enlarge the sample of intrinsic rotation periods and accurate light-curve amplitudes and to extend it to smaller sizes. Results and Discusions We requested 26 nights of observation in the second semester of 2007, to begin with the survey. They were scheduled for the following instruments

  2. Basalt here, basalt there: Constraining the basaltic nature of eight Vp-type asteroids in the inner and outer main asteroid belt

    Science.gov (United States)

    Hardersen, Paul Scott; Reddy, Vishnu

    2016-10-01

    The distribution and abundance of basaltic material in the main asteroid belt has multiple implications that impact our understanding of the physical and thermal conditions that existed in the inner solar system during the formation epoch about 4.6 Gyr ago. Subjects impacted by a more accurate basaltic asteroid inventory include the efficacy of current inner solar system heating model predictions (Al-26 and T Tauri induction heating), the existence of differentiated parent bodies other than (4) Vesta, the dispersion efficiency of Vestoids by YORP forces, and the predictive ability of the V-taxonomy in predicting a basaltic surface composition. This work reports on a continuation of an effort to better constrain the basaltic asteroid population in the main asteroid belt with the goal of observing about 650 Vp-type asteroids. This work focuses on two populations: a) those Vp-classified asteroids (Carvano et al., 2010) in the spatial vicinity of (4) Vesta (candidate Vestoids) in the inner main belt, and b) Vp-classified asteroids in the outer main belt beyond 2.5 AU. Thus far, 23 Vp-type asteroids and candidate Vestoids have been observed and analyzed, which are all strongly suggestive of a basaltic surface composition (Hardersen et al., 2014, 2015, 2016 (in preparation)). However, unpublished work is beginning to show that the Vp taxonomic class is less accurate in its ability to identify basaltic surface compositions in outer-belt Vp-type asteroids. We report here on an additional set of Vp-type asteroids that were observed at the NASA Infrared Telescope Facility (IRTF) in December 2015 and January 2016. All observations were obtained with the SpeX spectrograph in prism mode with spectral range from 0.7 to 2.5 microns. They include (4900) Maymelou, (7302) 1993 CQ, (9064) Johndavies, (9531) Jean-Luc, (11341) Babbage, (17480) 1991 PE10, (20171) 1996 WC2, and (25849) 2000 ET107. We present average near-infrared (NIR) reflectance spectra of each asteroid, determine the

  3. Digital Tracking Observations Can Discover Asteroids 10 Times Fainter Than Conventional Searches

    Science.gov (United States)

    Heinze, Aren N.; Metchev, Stanimir; Trollo, Joseph

    2015-10-01

    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 10 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 have yet been attempted. Our search for main belt asteroids using a one-degree imager on the 0.9 m WIYN telescope on Kitt Peak validates our methodology, delivers sensitivity to asteroids in a regime previously probed only with 4-m and larger instruments, and leads to the detection of 156 previously unknown asteroids and 59 known objects in a single field. Digital tracking has the potential to revolutionize searches for faint moving objects ranging from the Kuiper Belt through main belt and near-Earth asteroids, and perhaps even anthropogenic space debris in low Earth orbit.

  4. Impact risk assessment and planetary defense mission planning for asteroid 2015 PDC

    Science.gov (United States)

    Vardaxis, George; Sherman, Peter; Wie, Bong

    2016-05-01

    In this paper, an integrated utilization of analytic keyhole theory, B-plane mapping, and planetary encounter geometry, augmented by direct numerical simulation, is shown to be useful in determining the impact risk of an asteroid with the Earth on a given encounter, as well on potential future encounters via keyhole passages. The accurate estimation of the impact probability of hazardous asteroids is extremely important for planetary defense mission planning. Asteroids in Earth resonant orbits are particularly troublesome because of the continuous threat they pose in the future. Based on the trajectories of the asteroid and the Earth, feasible mission trajectories can be found to mitigate the impact threat of hazardous asteroids. In order to try to ensure mission success, trajectories are judged based on initial and final mission design parameters that would make the mission easier to complete. Given the potential of a short-warning time scenario, a disruption mission considered in this paper occurs approximately one year prior to the anticipated impact date. Expanding upon the established theory, a computational method is developed to estimate the impact probability of the hazardous asteroid, in order to assess the likelihood of an event, and then investigate the fragmentation of the asteroid due to a disruption mission and analyze its effects on the current and future encounters of the fragments with Earth. A fictional asteroid, designated as 2015 PDC - created as an example asteroid risk exercise for the 2015 Planetary Defence Conference, is used as a reference target asteroid to demonstrate the effectiveness and applicability of computational tools being developed for impact risk assessment and planetary defense mission planning for a hazardous asteroid or comet.

  5. Assessing the physical nature of near-Earth asteroids through their dynamical histories

    CERN Document Server

    Fernández, Julio A; Gallardo, Tabaré; Gutiérrez, Jorge N

    2014-01-01

    We analyze a sample of 139 near-Earth asteroids (NEAs), defined as those that reach perihelion distances $q 4.8$ au), having Tisserand parameters $2 4.8$ au of cometary origin, but it could be even lower if the NEAs in unstable orbits listed before turn out to be {\\it bona fide} asteroids from the main belt.

  6. Aqueous alteration on main belt primitive asteroids: results from visible spectroscopy

    CERN Document Server

    Fornasier, S; Barucci, M A; Lazzarin, M

    2014-01-01

    This work focuses on the study of the aqueous alteration process which acted in the main belt and produced hydrated minerals on the altered asteroids. The aqueous alteration is particularly important for unraveling the processes occurring during the earliest times of the Solar System history, as it can give information both on the asteroids thermal evolution and on the localization of water sources in the asteroid belt. We present new spectral observations in the visible region of 80 asteroids belonging to the primitive classes C, G, F, B and P. We combine the present observations with the visible spectra of asteroids available in the literature for a total of 600 primitive main belt asteroids. Our analysis shows that the aqueous alteration sequence starts from the P-type objects, practically unaltered, and increases through the F, B, C, and G asteroids. Around 50% of the observed C-type asteroids show absorption features in the vis. range due to hydrated silicates, implying that more than 70% of them will ha...

  7. Physical Characterization and Origin of Binary Near-Earth Asteroid (175706) 1996 FG3

    NARCIS (Netherlands)

    Walsh, Kevin J.; Delbo', Marco; Mueller, Michael; Binzel, Richard P.; DeMeo, Francesca E.

    2012-01-01

    The near-Earth asteroid (NEA) (175706) 1996 FG3 is a particularly interesting spacecraft target: a binary asteroid with a low-Δv heliocentric orbit. The orbit of its satellite has provided valuable information about its mass density while its albedo and colors suggest it is primitive or part of the

  8. Bulk Densities of Binary Asteroids from the Warm Spitzer NEO Survey

    NARCIS (Netherlands)

    Kistler, John; Trilling, D. E.; Mueller, M.; Hora, J. L.; Harris, A. W.; Bhattacharya, B.; Bottke, W. F.; Chesley, S.; Emery, J. P.; Fazo, G.; Mainzer, A.; Penprase, B.; Smith, H. A.; Spahr, T. B.; Stansberry, J. A.; Thomas, C. A.

    2010-01-01

    The Warm Spitzer NEO survey, ExploreNEOs, will observe approximately 700 Near Earth Asteroids. Several of these objects are known to be binary asteroid systems. Binary systems are interesting due to the unique opportunity they present for determining the masses and densities of their constituent bod

  9. Asteroid Lightcurve Analysis at CS3-Palmer Divide Station: 2015 June-September

    Science.gov (United States)

    Warner, Brian D.

    2016-01-01

    Lightcurves for 29 main-belt asteroids were obtained at the Center for Solar System Studies-Palmer Divide Station (CS3-PDS) from 2015 June-September. Hungaria members 1876 Napolitania and (47141) 1999 HB3 are suspected binary asteroids.

  10. Trajectory and physical properties of near-Earth asteroid 2009 BD

    NARCIS (Netherlands)

    Farnocchia, D.; Mommert, M.; Hora, J. L.; Chesley, S. R.; Vokrouhlický, D.; Trilling, D. E.; Mueller, M.; Harris, A. W.; Smith, H. A.; Fazio, G. G.; Knežević, Zoran; Lemaitre, Anne

    2014-01-01

    We analyze the trajectory of near-Earth asteroid 2009~BD, which is a candidate target of the NASA Asteroid Redirect Mission. The small size of 2009 BD and its Earth-like orbit pose challenges to understanding the dynamical properties of 2009 BD. In particular, nongravitational perturbations, such as

  11. Mid-infrared Spectra of Binary Asteroids With Spitzer/IRS

    NARCIS (Netherlands)

    Marchis, Franck; Emery, J. P.; Iglesias, J.; Pollock, J.; Mueller, M.; Harris, A. W.; Michalowski, T.; Berthier, J.; Descamps, P.

    2008-01-01

    To date, 162 asteroids are known to be binary or multiple systems. Insights, such as the size and shape of their components, the nature of their surface, their bulk density are the key to understanding how these multiple asteroidal systems formed. We obtained 19.9h of observations using the Spitzer/

  12. Modelling of asteroid formation in planetary vortex and calculation its orbital parameters

    Directory of Open Access Journals (Sweden)

    L. V. Klychinska

    2015-01-01

    Full Text Available The theory of planetary vortex as the initial state of creation of the star systems is used to the study of conditions of formation of asteroids and calculation its orbital parameters. In application to Main asteroid belt of the Solar system the kind coincidence of theoretical and experimental data is got.

  13. Near-infrared spectra of high-albedo outer main-belt asteroids

    Energy Technology Data Exchange (ETDEWEB)

    Kasuga, Toshihiro; Shirahata, Mai [National Institutes of Natural Science, National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo, 181-8588 (Japan); Usui, Fumihiko [Department of Astronomy, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Kuroda, Daisuke [Okayama Astrophysical Observatory, National Astronomical Observatory of Japan, 3037-5 Honjo, Kamogata-cho, Asakuchi, Okayama 719-0232 (Japan); Ootsubo, Takafumi [Department of Earth Science and Astronomy, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo, 153-8902 (Japan); Okamura, Natsuko [Department of Complexity Science and Engineering, The University of Tokyo Kiban Bldg. 408, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8561 (Japan); Hasegawa, Sunao, E-mail: toshi.kasuga@nao.ac.jp [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 252-5210 (Japan)

    2015-02-01

    Most outer main-belt asteroids have low albedos because of their carbonaceouslike bodies. However, infrared satellite surveys have revealed that some asteroids have high albedos, which may suggest the presence of unusual surface minerals for those primitive objects. We present new near-infrared (1.1–2.5 μm) spectra of four outer main-belt asteroids with albedos ≥ 0.1. The C-complex asteroids (555) Norma and (2542) Calpurnia are featureless and have (50%–60%) amorphous Mg pyroxenes that might explain the high albedos. Asteroids (701) Oriola (which is a C-complex asteroid) and (2670) Chuvashia (a D/T-type or M-type asteroid) show possible broad absorption bands (1.5–2.1 μm). The feature can be reproduced by either Mg-rich amorphous pyroxene (with 50%–60% and 80%–95% Mg, respectively) or orthopyroxene (crystalline silicate), which might be responsible for the high albedos. No absorption features of water ice (near 1.5 and 2.0 μm) are detected in the objects. We discuss the origin of high albedo components in the outer main-belt asteroids and their physical relations to comets.

  14. Effect of the finite size of an asteroid on its deflection using a tether-ballast system

    Science.gov (United States)

    Mashayekhi, Mohammad J.; Misra, Arun K.

    2016-07-01

    Potentially hazardous near-Earth objects which can impose a significant threat on life on the planet have generated a lot of interest in the study of various asteroid deflection strategies. There are numerous asteroid deflection techniques suggested and discussed in the literature. This paper is focused on one of the non-destructive asteroid deflection strategies by attaching a long tether-ballast system to the asteroid. In the existing literature on this technique, very simplified models of the asteroid-tether-ballast system including a point mass model of the asteroid have been used. In this paper, the dynamical effect of using a finite size asteroid model on the asteroid deflection achieved is analyzed in detail. It has been shown that considering the finite size of the asteroid, instead of the point mass approximation, can have significant influence on the deflection predicted. Furthermore the effect of the tether-deployment stage, which is an essential part of any realistic asteroid deflection mission, on the predicted deflection is studied in this paper. Finally the effect of cutting the tether on the deflection achieved is analyzed and it has been shown that depending on the orbital properties of the asteroid as well as its size and rotational rate, cutting the tether at an appropriate time can increase the deflection achieved. Several numerical examples have been used in this paper to elaborate on the proposed technique and to quantitatively analyze the effect of different parameters on the asteroid deflection.

  15. Preface: Advances in asteroid and space debris science and technology - Part 2

    Science.gov (United States)

    Vasile, Massimiliano

    2016-04-01

    Asteroids and space debris represent a significant hazard for space and terrestrial assets; at the same time asteroids represent also an opportunity. In recent years it has become clear that the increasing population of space debris could lead to catastrophic consequences in the near term. The Kessler syndrome (where the density of objects in orbit is high enough that collisions could set off a cascade) is more realistic than when it was first proposed in 1978. Although statistically less likely to occur, an asteroid impact would have devastating consequences for our planet. Although an impact with a large (∼10 km) to medium (∼300 m) sized, or diameter, asteroid is unlikely, still it is not negligible as the recent case of the asteroid Apophis has demonstrated. Furthermore impacts with smaller size objects, between 10 m and 100 m diameter, are expected to occur more frequently and hence are, proportionally, equally dangerous for humans and assets on Earth and in space.

  16. Use of a scanning CCD to discriminate asteroid images moving in a field of stars

    Science.gov (United States)

    Mcmillan, R. S.; Scotti, J. V.; Frecker, J. E.; Gehrels, T.; Perry, M. L.

    1986-01-01

    In the presently revealed use of a CCD in scanning mode to recover asteroids and comet nuclei, discover new asteroids in the main belt, and follow up the astrometry of selected new asteroids, the routine limiting visual magnitude is 19.6. Semiautomatic software for detection of moving objects is in use, allowing angular speeds as low as 11.0 arcsec/hr to be distinguished from the effects of the earth's atmosphere on the field of view. A typical set of three 29-min scans near the opposition point along the ecliptic typically nets at least five new main belt asteroids down to magnitude 19.6. In 18 monthly observing runs, 59 new asteroids have been obtained and 22 comets have been located.

  17. Dynamics of asteroids and near-Earth objects from Gaia Astrometry

    CERN Document Server

    Bancelin, D; Thuillot, W

    2016-01-01

    Gaia is an astrometric mission that will be launched in spring 2013. There are many scientific outcomes from this mission and as far as our Solar System is concerned, the satellite will be able to map thousands of main belt asteroids (MBAs) and near-Earth objects (NEOs) down to magnitude < 20. The high precision astrometry (0.3-5 mas of accuracy) will allow orbital improvement, mass determination, and a better accuracy in the prediction and ephemerides of potentially hazardous asteroids (PHAs). We give in this paper some simulation tests to analyse the impact of Gaia data on known asteroids' orbit, and their value for the analysis of NEOs through the example of asteroid (99942) Apophis. We then present the need for a follow-up network for newly discovered asteroids by Gaia, insisting on the synergy of ground and space data for the orbital improvement.

  18. Matching asteroid population characteristics with a model constructed from the YORP-induced rotational fission hypothesis

    CERN Document Server

    Jacobson, Seth Andrew; Rossi, Alessandro; Scheeres, Daniel J

    2016-01-01

    From the results of a comprehensive asteroid population evolution model, we conclude that the YORP-induced rotational fission hypothesis can be consistent with the observed population statistics of small asteroids in the main belt including binaries and contact binaries. The foundation of this model is the asteroid rotation model of Marzari et al. (2011), which incorporates both the YORP effect and collisional evolution. This work adds to that model the rotational fission hypothesis and the binary evolution model of Jacobson & Scheeres (2011). The asteroid population evolution model is highly constrained by these and other previous works, and therefore it has only two significant free parameters: the ratio of low to high mass ratio binaries formed after rotational fission events and the mean strength of the binary YORP (BYORP) effect. We successfully reproduce characteristic statistics of the small asteroid population: the binary fraction, the fast binary fraction, steady-state mass ratio fraction and the...

  19. THE PUZZLING MUTUAL ORBIT OF THE BINARY TROJAN ASTEROID (624) HEKTOR

    Energy Technology Data Exchange (ETDEWEB)

    Marchis, F.; Cuk, M. [Carl Sagan Center at the SETI Institute, Mountain View, CA 94043 (United States); Durech, J. [Astronomical Institute, Faculty of Mathematics and Physics, Charles University, Prague (Czech Republic); Castillo-Rogez, J. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Vachier, F.; Berthier, J. [IMCCE-Obs de Paris, F-75014 Paris (France); Wong, M. H.; Kalas, P.; Duchene, G. [Department of Astronomy, University of California at Berkeley, Berkeley, CA 94720 (United States); Van Dam, M. A. [Flat Wavefronts, Christchurch 8140 (New Zealand); Hamanowa, H. [Hamanowa Observatory, Motomiya, Fukushima 969-1204 (Japan); Viikinkoski, M., E-mail: fmarchis@seti.org [Tampere University of Technology, FI-33101 Tampere (Finland)

    2014-03-10

    Asteroids with satellites are natural laboratories to constrain the formation and evolution of our solar system. The binary Trojan asteroid (624) Hektor is the only known Trojan asteroid to possess a small satellite. Based on W. M. Keck adaptive optics observations, we found a unique and stable orbital solution, which is uncommon in comparison to the orbits of other large multiple asteroid systems studied so far. From lightcurve observations recorded since 1957, we showed that because the large Req = 125 km primary may be made of two joint lobes, the moon could be ejecta of the low-velocity encounter, which formed the system. The inferred density of Hektor's system is comparable to the L5 Trojan doublet (617) Patroclus but due to their difference in physical properties and in reflectance spectra, both captured Trojan asteroids could have a different composition and origin.

  20. Modeling Asteroid Geometries using Photometry at the Glendale Community College North Observatory

    Science.gov (United States)

    Gleim, Brian; Santana, Cristian; Smith, Blake; Cheff, Martha; Muniz, Gonzalo; Boyer, Elizabeth; Keegan, Justin; Dixon, Justin; Baker, Frankie; Karpurk, Kaitlynn; Rodriguez, Anjelica; Bolinaga, Andres; Acosta, Erik; Powell, Bailie; Watt, Sara D.; Eardley, Brandon; Watt, Keith; Jones, Isaac

    2016-01-01

    The students of the Glendale Community College's Astronomy Students for Telescope Research and Outreach (A.S.T.R.O.) Club have expanded their exoplanet transit observing program into observing asteroids. The students, most of whom are non-science majoring undergraduates, observed the asteroid 15 Eunomia using the 8-inch telescopes at the GCC North Observatory in Glendale, Arizona.Using concepts and skills learned in introductory astronomy courses for non-science majors, the co-authors measured the variability of the asteroid due to its rotation and constructed its lightcurve. Using the lightcurve inversion software from the Database of Asteroid Models from Inversion Techniques (DAMIT), a 3-dimensional model of the shape of 15 Eunomia was calculated. These results demonstrate that, given equipment that is readily available and affordable, asteroid observations have long-term educational potential for authentic, practical experience in both observational astronomy and numerical modeling, even with a small student body majoring in the physical sciences.

  1. Radar Observations and the Shape of Near-Earth Asteroid 2008 EV5

    CERN Document Server

    Busch, Michael W; Benner, Lance A M; Brozovic, Marina; Giorgini, Jon D; Jao, Joseph S; Scheeres, Daniel J; Magri, Christopher; Nolan, Michael C; Howell, Ellen S; Taylor, Patrick A; Margot, Jean-Luc; Brisken, Walter

    2011-01-01

    We observed the near-Earth asteroid 2008 EV5 with the Arecibo and Goldstone planetary radars and the Very Long Baseline Array during December 2008. EV5 rotates retrograde and its overall shape is a 400 /pm 50 m oblate spheroid. The most prominent surface feature is a ridge parallel to the asteroid's equator that is broken by a concavity 150 m in diameter. Otherwise the asteroid's surface is notably smooth on decameter scales. EV5's radar and optical albedos are consistent with either rocky or stony-iron composition. The equatorial ridge is similar to structure seen on the rubble-pile near-Earth asteroid (66391) 1999 KW4 and is consistent with YORP spin-up reconfiguring the asteroid in the past. We interpret the concavity as an impact crater. Shaking during the impact and later regolith redistribution may have erased smaller features, explaining the general lack of decameter-scale surface structure.

  2. A correct selection of asteroid families and confirmation of a nongravitational effect action

    CERN Document Server

    Kazantsev, A M

    2016-01-01

    The distribution of asteroid sizes by semimajor axes and the distribution of the number of asteroids by albedo values for separate families are used to selection the asteroid families more clearly. An analysis of the families identified by Masiero et al. (2013) was carried out with the use of the distributions of D(a) and N(p), there were defined correctly and incorrectly selected families. A decreasing of the mean albedo with semi-major axis increasing take place almost for all correctly selected families and which are not truncated by resonances. The decrease is statistically significant for the majority of these families. There is none family at a significant increase of albedo. This confirms our previous conclusion on existence of a non-gravitational effect in the asteroid belt which causes the spatial separation of asteroids with different albedos.

  3. Mission options for the first SEPS application. [rendezvous with near earth asteroids and comets

    Science.gov (United States)

    Yen, C.-W. L.

    1981-01-01

    Missions to comets and asteroids are primary candidates for Solar Electric Propulsion System (SEPS) applications. NASA estimates that the first SEPS mission might be launched as early as 1988. This paper presents mission opportunities available for launches between 1988 and early 1991 and discusses the performance capabilities of the current SEPS. Use of a Shuttle Two-Stage IUS and/or a Shuttle Wide Tank Centaur launch vehicle is assumed in the performance assessment. The list of possible first SEPS missions consists of nine missions to comets of primary interest and examples of multiple asteroid rendezvous missions. Both an earth crossing asteroid and a main belt asteroid are considered as first possible targets in the multiple asteroid rendezvous examples. Mission opportunity and performance maps for Eros and Anteros are presented which provide exact performance data and optimal launch and arrival dates for any launch year.

  4. Autonomous determination of orbit for probe around asteroids using unscented Kalman filter

    Institute of Scientific and Technical Information of China (English)

    崔平远; 崔祜涛; 黄翔宇; 栾恩杰

    2003-01-01

    The observed images of the asteroid and the asteroid reference images are used to obtain the probe-to-asteroid direction and the location of the limb features of the asteroid in the inertial coordinate. These informa-tion in combination with the shape model of the asteroid and attitude information of the probe are utilized to ob-tain the position of the probe. The position information is then input to the UKF which determines the real-timeorbit of the probe. Finally, the autonomous orbit determination algorithm is validated using digital simulation.The determination of orbit using UKF is compared with that using extended Kalman filter (EKF), and the resultshows that UKF is superior to EKF.

  5. High-Resolution Imaging of Asteroids/Satellites with AO

    Science.gov (United States)

    Merline, William

    2012-02-01

    We propose to make high-resolution observations of asteroids using AO, to measure size, shape, and pole position (spin vectors), and/or to search for satellites. We have demonstrated that AO imaging allows determination of the pole/dimensions in 1 or 2 nights on a single target, rather than the years of observations with lightcurve inversion techniques that only yield poles and axial ratios, not true dimensions. Our new technique (KOALA) combines AO imaging with lightcurve and occultation data for optimum size/shape determinations. We request that LGS be available for faint targets, but using NGS AO, we will measure several large and intermediate asteroids that are favorably placed in spring/summer of 2012 for size/shape/pole. Accurately determining the volume from the often-irregular shape allows us to derive densities to much greater precision in cases where the mass is known, e.g., from the presence of a satellite. We will search several d! ozen asteroids for the presence of satellites, particularly in under-studied populations, particularly NEOs (we have recently achieved the first-ever optical image of an NEO binary [Merline et al. 2008b, IAUC 8977]). Satellites provide a real-life lab for testing collisional models. We will search for satellites around special objects at the request of lightcurve observers, and we will make a search for debris in the vicinity of Pluto, in support of the New Horizons mission. Our shape/size work requires observations over most of a full rotation period (typically several hours).

  6. Howardite Noble Gases as Indicators of Asteroid Surface Processing

    Science.gov (United States)

    Cartwright, J. A.; Mittlefehldt, D. W.; Herrin, J. S.; Ott, U.

    2011-01-01

    The HED (Howardite, Eucrite and Diogenite) group meteorites likely or iginate from the Asteroid 4 Vesta - one of two asteroid targets of NA SA's Dawn mission. Whilst Howardites are polymict breccias of eucriti c and diogenitic material that often contain "regolithic" petrologica l features, neither their exact regolithic nature nor their formation processes are well defined. As the Solar Wind (SW) noble gas compon ent is implanted onto surfaces of solar system bodies, noble gas anal yses of Howardites provides a key indicator of regolithic origin. In addition to SW, previous work by suggested that restricted Ni (300-12 00 micro g/g) and Al2O3 (8-9 wt%) contents may indicate an ancient we ll-mixed regolith. Our research combines petrological, compositional and noble gas analyses to help improve understanding of asteroid reg olith formation processes, which will play an intergral part in the i nterpretation of Dawn mission data. Following compositional and petrological analyses, we developed a regolith grading scheme for our sampl e set of 30 Howardites and polymict Eucrites. In order to test the r egolith indicators suggested by, our 8 selected samples exhibited a r ange of Ni, Al2O3 contents and regolithic grades. Noble gas analyses were performed using furnace stepheating on our MAP 215-50 noble gas mass spectrometer. Of our 8 howardites, only 3 showed evidence of SW noble gases (e.g approaching Ne-20/Ne-22 approximately equals 13.75, Ne-21/Ne-22 approximately equals 0.033). As these samples display low regolithic grades and a range of Ni and Al2O3 contents, so far we are unable to find any correlation between these indicators and "regolit hic" origin. These results have a number of implications for both Ho wardite and Vesta formation, and may suggest complex surface stratigr aphies and surface-gardening processes.

  7. On the vW leptokurtic asteroid families

    Science.gov (United States)

    Carruba, Valerio; Nesvorny, David; Cassia Domingos, Rita; Aljbaae, Safwan; Espinoza Huaman, Mariela

    2016-10-01

    vW leptokurtic asteroid families are families for which the distribution of the normal component of the terminal ejection velocity field v W is characterized by a positive value of the γ2 Pearson kurtosis, i.e., they have a distribution with a more concentrated peak and larger tails than the Gaussian one. Currently, eight families are known to have γ2(vW) > 0.25. This may be caused by the fact that i) the family did not alter significantly its originally leptokurtic inclination distribution since its formation, as it seems to be the case for the Koronis family or ii) some of the family members interacted with a strong node secular resonances, as it is the case for the Astrid (interaction with the s-sC resonance with Ceres) and Gallia (interaction with the s-sV resonance with Vesta) families.In this work, we investigate the families that were affected by strong secular resonances with massive asteroids. By obtaining the time evolution of γ2(vW) for simulated families under the gravitational influence of planets and the three most massive bodies in the main belt we were able to i) assess the dynamical importance (or lack of) node secular resonances with Ceres, Vesta, and Pallas for the considered families, ii) obtain independent constraints on the family ages, and iii) for the case of the Astrid family set limitations on values of key parameters of the Yarkovsky force such as the surface thermal conductivity and the mean density of members. Overall, the use of the γ2(vW) parameter could provide useful hints on the original ejection velocity field and dynamical evolution of leptokurtic vW asteroid families.

  8. 322P/SOHO 1: Sunskirting Comet or Asteroid?

    Science.gov (United States)

    Knight, Matthew M.; Fitzsimmons, Alan; Kelley, Michael S. P.; Snodgrass, Colin

    2015-11-01

    Comet 322P/SOHO 1 (P/1999 R1) is a unique object: a short period comet (P = 3.99 yr) on a “sunskirting orbit” (q = 0.053 AU, or ~11 solar radii) with no dynamical linkage to any other known comets. 322P was discovered in SOHO images in 1999, and has been seen by SOHO on every subsequent orbit: 2003, 2007, and 2011 (it is expected to be observed by SOHO again during its next perihelion passage in 2015 September). During this time it has not displayed an obvious coma or tail in SOHO images, but has exhibited a non-asteroidal lightcurve that strongly suggests the presence of an unresolved coma. Equilibrium temperatures during these observations exceed 1000 K, so it is unclear if 322P is active due to sublimation of volatile ices like a typical comet or if it is an otherwise inactive object that is losing material through more exotic processes such as sublimation of refractory materials or thermal fracturing. Due to the very large uncertainty in orbits derived from SOHO observations and 322P’s assumed small size, 2015 was the first reasonable opportunity to recover it at large heliocentric distance and attempt to determine its heritage: traditional comet or asteroid. We recovered 322P on 2015 May 22 with the VLT and observed it again on five epochs in June and July with Spitzer, the VLT, and the Discovery Channel Telescope. These are the first successful observations of any SOHO-discovered short period comet at traditional cometary distances. 322P appeared pointlike in all images (heliocentric distances from 2.1 to 1.2 AU), implying an inactive object having a diameter of a few hundred meters. We will report on these observations, focusing on constraining properties of 322P such as activity level, color, and albedo that may help us deduce whether or not it is of a cometary or asteroidal origin.

  9. Drifting asteroid fragments around WD 1145+017

    Science.gov (United States)

    Rappaport, S.; Gary, B. L.; Kaye, T.; Vanderburg, A.; Croll, B.; Benni, P.; Foote, J.

    2016-06-01

    We have obtained extensive photometric observations of the polluted white dwarf WD 1145+017 which has been reported to be transited by at least one, and perhaps several, large asteroids with dust emission. Observation sessions on 37 nights spanning 2015 November to 2016 January with small to modest size telescopes have detected 237 significant dips in flux. Periodograms reveal a significant periodicity of 4.5004 h consistent with the dominant (`A') period detected with K2. The folded light curve shows an hour-long depression in flux with a mean depth of nearly 10 per cent. This depression is, in turn, comprised of a series of shorter and sometimes deeper dips which would be unresolvable with K2. We also find numerous dips in flux at other orbital phases. Nearly all of the dips associated with this activity appear to drift systematically in phase with respect to the `A' period by about 2.5 min d-1 with a dispersion of ˜0.5 min d-1, corresponding to a mean drift period of 4.4928 h. We are able to track ˜15 discrete drifting features. The `B'-`F' periods found with K2 are not detected, but we would not necessarily have expected to see them. We explain the drifting motion as due to smaller fragmented bodies that break off from the asteroid and go into a slightly smaller orbit. In this interpretation, we can use the drift rate to determine the mass of the asteroid, which we find to be ≈1023 g, or about 1/10th the mass of Ceres.

  10. 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 Earth. Using touch-and-go (TAG), a few seconds of contact is adequate for the gas-driven collection technique to acquire sample. This TAGSAM system has been developed and extensively tested in ground tests, and also on reduced-gravity airplane flights, to evaluate collection efficiency for various surfaces

  11. Using Simple Shapes to Constrain Asteroid Thermal Inertia

    Science.gov (United States)

    MacLennan, Eric M.; Emery, Joshua P.

    2015-11-01

    With the use of remote thermal infrared observations and a thermophysical model (TPM), the thermal inertia of an asteroid surface can be determined. The thermal inertia, in turn, can be used to infer physical properties of the surface, specifically to estimate the average regolith grain size. Since asteroids are often non-spherical techniques for incorporating modeled (non-spherical) shapes into calculating thermal inertia have been established. However, using a sphere as input for TPM is beneficial in reducing running time and shape models are not generally available for all (or most) objects that are observed in the thermal-IR. This is particularly true, as the pace of infrared observations has recently dramatically increased, notably due to the WISE mission, while the time to acquire sufficient light curves for accurate shape inversion remains relatively long. Here, we investigate the accuracy of using both a spherical and ellipsoidal TPM, with infrared observations obtained at pre- and post-opposition (hereafter multi-epoch) geometries to constrain the thermal inertias of a large number of asteroids.We test whether using multi-epoch observations combined with a spherical and ellipsoidal shape TPM can constrain the thermal inertia of an object without a priori knowledge of its shape or spin state. The effectiveness of this technique is tested for 16 objects with shape models from DAMIT and WISE multi-epoch observations. For each object, the shape model is used as input for the TPM to generate synthetic fluxes for different values of thermal inertia. The input spherical and ellipsoidal shapes are then stepped through different spin vectors as the TPM is used to generate best-fit thermal inertia and diameter to the synthetically generated fluxes, allowing for a direct test of the approach’s effectiveness. We will discuss whether the precision of the thermal inertia constraints from the spherical TPM analysis of multi- epoch observations is comparable to works

  12. 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_maxstudied in terms of their spins and shapes. Our campaign targets a sample of around 100 bright (Hadaptive 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.

  13. The Evolutionary Outcomes of Expansive Binary Asteroid Systems

    Science.gov (United States)

    McMahon, Jay W.

    2016-10-01

    Singly synchronous binary asteroid systems have several evolutionary end-states, which depend heavily on the BYORP effect. In the case of expansive BYORP, the binary system could evolve to become a wide asynchronous binary system (Jacobson, et al 2014), or the system could expand far enough to become disrupted to form a heliocentric pair (Vokrouhlicky et al 2008). Cuk et al (2011) found that upon expanding the secondary will quickly become asynchronous, and will end up re-establishing synchronous rotation with the opposite attitude, causing the binary orbit to subsequently contract. The distinction between these outcomes depends on whether the secondary asteroid stays synchronized, which keeps the BYORP effect active and the orbit expanding. As the orbit expands, the secondary libratation will expand, and the libration will also causes large variations in the binary orbit due to the elongation of the secondary. If the eccentricity and libration are bound to small enough values the system can expand significantly. This work discusses the stability of the libration and orbital motion as a binary expands from a wide variety of simulation runs with various parameters. We investigate how the strength of tides and BYORP change the stability of the librational motion; an important factor is the speed of BYORP expansion as slower expansion allows tides to have a more stabilizing effect. We also investigate the effect of heliocentric orbit semimajor axis and eccentricity. We find that resonances between the coupled orbit-libration frequencies and the heliocentric orbit cause instability in the binary orbit eccentricity which produces a strong preference for wide binary production, especially amongst retrograde binary systems. This instability also becomes stronger with large heliocentric eccentricities. Prograde binaries are more stable and can possible grow to become asteroid pairs. We find that even in the presence of tides, reestablishment of synchronous spin into a

  14. Heliocentric zoning of the asteroid belt by aluminum-26 heating

    Science.gov (United States)

    Grimm, R. E.; Mcsween, H. Y., Jr.

    1993-01-01

    Variations in petrology among meteorites attest to a strong heating event early in solar system history, but the heat source has remained unresolved. Aluminum-26 has been considered the most likely high-energy, short-lived radionuclide (half-life 0.72 million years) since the discovery of its decay product - excess Mg-26 - in Allende CAI's. Furthermore, observation of relict Mg-26 in an achondritic clast and in feldspars within ordinary chondrites (3,4) provided strong evidence for live Al-26 in meteorite parent bodies and not just in refractory nebular condensates. The inferred amount of Al-26 is consistent with constraints on the thermal evolution of both ordinary and carbonaceous chondrite parent objects up to a few hundred kilometers in diameter. Meteorites can constrain the early thermal evolution of their parent body locations, provided that a link can be established between asteroid spectrophotometric signature and meteorite class. Asteroid compositions are heliocentrically distributed: objects thought to have experienced high metamorphic or even melting temperatures are located closer to the sun, whereas apparently unaltered or mildly heated asteroids are located farther away. Heliocentric zoning could be the result of Al-26 heating if the initial amount of the radionuclide incorporated into planetesimals was controlled by accretion time, which in turn varies with semimajor axis. Analytic expressions for planetary accretion may be integrated to given the time, tau, required for a planetesimal to grow to a specified radius: tau varies as a(sup n), where n = 1.5 to 3 depending on the assumptions about variations in the surface density of the planetesimal swarm. Numerical simulations of planetesimal accretion at fixed semimajor axis demonstrate that variations in accretion time among small planetesimals can be strongly nonlinear depending on the initial conditions and model assumptions. The general relationship with semimajor axis remains valid because it

  15. Numerical Simulations of Spacecraft-Regolith Interactions on Asteroids

    Science.gov (United States)

    Ballouz, Ronald; Richardson, Derek C.; Michel, Patrick; Schwartz, Stephen R.

    2014-11-01

    NASA's OSIRIS-REx mission will rendezvous in 2018 with the near-Earth asteroid (101955) Bennu and attempt to touch down and obtain a sample from its surface. The regolith surface's behavior in response to the spacecraft's intrusion is difficult to predict due to the asteroid's extremely low-gravity environment (on the order of 10 micro-g's.) We have been carrying out high-resolution (N > 100,000) numerical simulations of the intrusion of a realistic physical model of the sampling device into a bed of cm-size spherical particles to explore the relationship between the spacecraft's response and the dynamical behavior of the regolith. If the granular bed is too compliant, then the spacecraft may sink into the asteroid. If the granular bed is not compliant enough, then the spacecraft may not be able to obtain an appropriate sample. This is further complicated by the fact that the degree of compliance is also dependent on the material properties of the regolith surface (size distribution, local slope, friction coefficients, shape effects). The ultimate goal of this study is to construct a library of touchdown outcomes as a function of the potential observables (local slope, estimated maximum angle of repose, and to a limited exited particle size distribution). We study the effect of varying the regolith's material properties (cohesive, frictional, and dissipative parameters) in order to place limits on the range of possible outcomes. The library will be useful for sample-site selection based on available observables, and, upon sampling, may aid in interpreting the physical properties of the regolith (e.g., depth and density) by comparing measurements from on-board instruments with simulation data. Preliminary results show that grains with low coefficients of friction (smooth particles) provide little resistance and the spacecraft sinks into the asteroid. For high coefficients of friction (effectively mimicking grain angularity), the regolith is much less compliant, and

  16. A Potpourri of Near-Earth Asteroid Observations

    Science.gov (United States)

    Tholen, David J.; Ramanjooloo, Yudish; Fohring, Dora; Hung, Denise; Micheli, Marco

    2016-10-01

    Ongoing astrometric follow-up of near-Earth asteroids has yielded a variety of interesting results. In the limited space of a DPS abstract, three recently observed objects are worth mentioning.2008 HU4 is among the most accessible asteroids for a human space flight mission. We successfully recovered this object at a second opposition on 2016 April 26 despite the large ephemeris uncertainty. The small size of this asteroid makes it relatively easy to detect the departure from purely gravitational motion caused by solar radiation pressure, which can be used to estimate the density of the object. At the time of this writing, the object remains bright enough for additional observations, so we expect to improve on our five-sigma detection of a relatively low density (roughly similar to water, indicating a high porosity) between now and the DPS meeting.2016 HO3 is a newly-discovered co-orbital with the Earth. Our 2016 May 10-11 observations extended the observational arc by enough to permit backward extrapolation that led to prediscovery observations by Pan-STARRS in 2015, and then annually back to 2011, and ultimately to Sloan DSS observations in 2004. The 12-year arc is sufficient to examine the dynamical behavior of the object, which shows how it will remain in the vicinity of the Earth for decades, if not centuries. Our observations also revealed a rapid rotation (less than a half hour) with large brightness variation (in excess of 1 magnitude), which helps to explain why this object eluded discovery until this year.2011 YV62 is among the top 20 largest near-Earth asteroids with Earth impact solutions (in 2078 and 2080). At the time of this writing, the object is flagged as being "lost", but a re-examination of observations made in 2013 and 2015 finally yielded a successful recovery at a magnitude fainter than 24. We expect the new observations to eliminate the impact possibilities. The story behind this difficult recovery is fascinating.

  17. Comet/Asteroid Impacts and Human Society An Interdisciplinary Approach

    CERN Document Server

    Bobrowsky, Peter T

    2007-01-01

    In 1908 an atmospheric explosion in northern Siberia released energy equivalent to 15 Mton of TNT. Can a comparable or larger NEO affect us again? When the next NEO strikes Earth will it be large enough to destroy a city? Will the climate change significantly? Can archaeology and anthropology provide insights into the expected cultural responses with NEO interactions? Does society have a true grasp of the actual risks involved? Is the Great Depression a good model for the economic collapse that could follow a NEO catastrophe? This volume provides a necessary link between various disciplines and comet/asteroid impacts.

  18. 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 driven collection technique to acquire sample. This TAGSAM system has been developed and extensively 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

  19. How to form asteroids from mm-sized grains

    CERN Document Server

    Carrera, Daniel; Davies, Melvyn B

    2016-01-01

    The size distribution of asteroids in the solar system suggests that they formed top-down, with 100-1000 km bodies forming from the gravitational collapse of dense clumps of small solid particles. We investigate the conditions under which solid particles can form dense clumps in a protoplanetary disc. We used a hydrodynamic code to model the solid-gas interaction in disc. We found that particles down to millimeter size can form dense clumps, but only in regions where solids make $\\sim$ 8% of the local surface density. More generally, we mapped the range of particle sizes and concentrations that is consistent with the formation of particle clumps.

  20. Sporotrichoid pattern of cutaneous nocardiasis due to Nocardia asteroids

    Directory of Open Access Journals (Sweden)

    Baradkar V

    2008-07-01

    Full Text Available Cutaneous nocardiosis is a rare disease, only a few cases of which have been reported from the world as well as in India. This infection, when in the lymphocutaneous form, may clinically resemble sporotrichosis, hence causing a diagnostic dilemma. Here, we report a case of primary cutaneous, sporotrichoid pattern of cutaneous nocardiosis caused by Nocardia asteroides in immunocompetent host. The patient was a 32-year-old farmer, with no predisposing factors, who presented with cutaneous nocardiosis. The diagnosis was confirmed by culture of the biopsy, after which the patient was treated successfully with antibacterial agents.