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  1. Asteroids, Comets, Meteors 2014

    Science.gov (United States)

    Muinonen, K.; Penttilä, A.; Granvik, M.; Virkki, A.; Fedorets, G.; Wilkman, O.; Kohout, T.

    2014-08-01

    Asteroids, Comets, Meteors focuses on the research of small Solar System bodies. Small bodies are the key to understanding the formation and evolution of the Solar System, carrying signals from pre-solar times. Understanding the evolution of the Solar System helps unveil the evolution of extrasolar planetary systems. Societally, small bodies will be important future resources of minerals. The near-Earth population of small bodies continues to pose an impact hazard, whether it be small pieces of falling meteorites or larger asteroids or cometary nuclei capable of causing global environmental effects. The conference series entitled ''Asteroids, Comets, Meteors'' constitutes the leading international series in the field of small Solar System bodies. The first three conferences took place in Uppsala, Sweden in 1983, 1985, and 1989. The conference is now returning to Nordic countries after a quarter of a century. After the Uppsala conferences, the conference has taken place in Flagstaff, Arizona, U.S.A. in 1991, Belgirate, Italy in 1993, Paris, France in 1996, Ithaca, New York, U.S.A. in 1999, in Berlin, Germany in 2002, in Rio de Janeiro, Brazil in 2005, in Baltimore, Maryland, U.S.A. in 2008, and in Niigata, Japan in 2012. ACM in Helsinki, Finland in 2014 will be the 12th conference in the series.

  2. Lunar and Planetary Science XXXV: Asteroids, Meteors, Comets

    Science.gov (United States)

    2004-01-01

    Reports included:Long Term Stability of Mars Trojans; Horseshoe Asteroids and Quasi-satellites in Earth-like Orbits; Effect of Roughness on Visible Reflectance Spectra of Planetary Surface; SUBARU Spectroscopy of Asteroid (832) Karin; Determining Time Scale of Space Weathering; Change of Asteroid Reflectance Spectra by Space Weathering: Pulse Laser Irradiation on Meteorite Samples; Reflectance Spectra of CM2 Chondrite Mighei Irradiated with Pulsed Laser and Implications for Low-Albedo Asteroids and Martian Moons; Meteorite Porosities and Densities: A Review of Trends in the Data; Small Craters in the Inner Solar System: Primaries or Secondaries or Both?; Generation of an Ordinary-Chondrite Regolith by Repetitive Impact; Asteroid Modal Mineralogy Using Hapke Mixing Models: Validation with HED Meteorites; Particle Size Effect in X-Ray Fluorescence at a Large Phase Angle: Importance on Elemental Analysis of Asteroid Eros (433); An Investigation into Solar Wind Depletion of Sulfur in Troilite; Photometric Behaviour Dependent on Solar Phase Angle and Physical Characteristics of Binary Near-Earth-Asteroid (65803) 1996 GT; Spectroscopic Observations of Asteroid 4 Vesta from 1.9 to 3.5 micron: Evidence of Hydrated and/or Hydroxylated Minerals; Multi-Wavelength Observations of Asteroid 2100 Ra-Shalom: Visible, Infrared, and Thermal Spectroscopy Results; New Peculiarities of Cometary Outburst Activity; Preliminary Shape Modeling for the Asteroid (25143) Itokawa, AMICA of Hayabusa Mission; Scientific Capability of MINERVA Rover in Hayabusa Asteroid Mission; Characteristics and Current Status of Near Infrared Spectrometer for Hayabusa Mission; Sampling Strategy and Curation Plan of Hayabusa Asteroid Sample Return Mission; Visible/Near-Infrared Spectral Properties of MUSES C Target Asteroid 25143 Itokawa; Calibration of the NEAR XRS Solar Monitor; Modeling Mosaic Degradation of X-Ray Measurements of 433 Eros by NEAR-Shoemaker; Scattered Light Remediation and Recalibration of

  3. Meteor Showers of the Earth-crossing Asteroids

    Science.gov (United States)

    Pulat, Babadzhanov; Gulchekhra, Kokhirova

    2015-03-01

    The results of search for meteor showers associated with the asteroids crossing the Earthfs orbit and moving on comet-like orbits are given. It was shown that among 2872 asteroids discovered till 1.01.2005 and belonging to the Apollo and Amor groups, 130 asteroids have associated meteor showers and, therefore, are the extinct cometary nuclei.

  4. Meteor Streams of Comet Encke. Taurid Meteor Complex

    OpenAIRE

    Klacka, Jozef

    1999-01-01

    Application of the theoretical results of the author are presented for the case of meteor streams of comet Encke. Theoretical determination of meteor orbit for comet Encke, as a parent body, is presented. Four significant theoretical meteor streams, corresponding to Tauds N, Tauds S, $\\beta$ Tauds and $\\xi$ Perds are found. The meteor stream membership criterion is applied to the photographic orbits of The IAU Meteor Data Center in Lund: Taurid meteor stream is found for several possible area...

  5. 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.

  6. 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

  7. Association between meteor showers and asteroids using multivariate criteria

    Science.gov (United States)

    Dumitru, B. A.; Birlan, M.; Popescu, M.; Nedelcu, D. A.

    2017-10-01

    Context. Meteoroid streams are fragments of matter produced by comets or asteroids which intersects the orbit of Earth. Meteor showers are produced when Earth intersects these streams of matter. The discoveries of active asteroids and extinct comets open a new view of the relation between these objects as possible parent bodies at the origin of meteor showers. Aims: The aim of this work is to identify the asteroids that can produce or re-populate meteoroid streams by determining the similarity of their orbits and orbital evolution over 10 000 yr. Methods: The identification was carried out by evaluating several well known D-criteria metrics, the orbits being taken from the IAU Meteor Data Center database and from IAU Minor Planet Center. Finally, we analyzed the physical properties and the orbital stability (in the Lyapunov time sense) of the candidates as well as their possible relationship with meteorites. Results: 206 near-Earth asteroids (NEAs) were associated as possible parent bodies with 28 meteor showers, according to at least two of the criterion used. 50 of them satisfied all the criteria. Notable finds are: binary asteroid 2000UG11 associated with Andromedids (AND), while the tumbling asteroid (4179)Toutatis could be associated with October Capricornids (OCC). Other possible good candidates are 2004TG10, 2008EY5, 2010CF55, 2010TU149 and 2014OY1. These objects have low albedo, therefore can be primitive objects. Asteroid 2007LW19 which is a fast rotator and most probably has monolithic structure and so its physical characteristic does not support the association found based on the dynamical criteria.

  8. Comet P/Machholtz and the Quadrantid meteor stream

    International Nuclear Information System (INIS)

    Mcintosh, B.A.

    1990-01-01

    Attention is drawn to the suggestive similarities between the calculated perturbation behavior of Comet P/Machholtz 1986 VIII, on the one hand, and on the other those of the Quadrantid, Delta Aquarid, and Arietid meteor streams. There appears to be adequate evidence for the formation by the Comets P/Machholtz and 1491-I, together with the three meteor streams, of a related complex controlled by Jupiter's gravitational perturbations; there is no comparably compelling information, however, bearing on the questions of parent-offspring or sibling relationships among these comets and meteor streams. 13 refs

  9. Direct Characterization of Comets and Asteroids via Cosmic Dust Analysis from the Deep Space Gateway

    Science.gov (United States)

    Fries, M.; Fisher, K.

    2018-01-01

    The Deep Space Gateway (DSG) may provide a platform for direct sampling of a large number of comets and asteroids, through employment of an instrument for characterizing dust from these bodies. Every year, the Earth traverses through debris streams of dust and small particles from comets and asteroids in Earth-crossing orbits, generating short-lived outbursts of meteor activity commonly known as "meteor showers" (Figure 1). The material in each debris stream originates from a distinct parent body, many of which have been identified. By sampling this material, it is possible to quantitatively analyze the composition of a dozen or more comets and asteroids (See Figure 2, following page) without leaving cislunar space.

  10. Reducing the Asteroid and Comet Impact Hazard

    Science.gov (United States)

    Crawford, David

    1998-10-01

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

  11. Dormant Comets in the Near-Earth Asteroid Population

    NARCIS (Netherlands)

    Mommert, Michael; Harris, Alan W.; Mueller, Michael; Hora, Joseph L.; Trilling, David E.; Knight, Matthew; Bottke, William F.; Thomas, Cristina; Delbo', Marco; Emery, Josh P.; Fazio, Giovanni; Smith, Howard A.

    2015-01-01

    The population of near-Earth objects comprises active comets and asteroids, covering a wide range of dynamical parameters and physical properties. Dormant (or extinct) comets, masquerading as asteroids, have long been suspected of supplementing the near-Earth asteroid (NEA) population. We present a

  12. Collecting Comet Samples by ER-2 Aircraft: Cosmic Dust Collection During the Draconid Meteor Shower in October 2012

    Science.gov (United States)

    Bastien, Ron; Burkett, P. J.; Rodriquez, M.; Frank, D.; Gonzalez, C.; Robinson, G.-A.; Zolensky, M.; Brown, P.; Campbell-Brown, M.; Broce, S.; hide

    2014-01-01

    Many tons of dust grains, including samples of asteroids and comets, fall from space into the Earth's atmosphere each day. NASA periodically collects some of these particles from the Earth's stratosphere using sticky collectors mounted on NASA's high-flying aircraft. Sometimes, especially when the Earth experiences a known meteor shower, a special opportunity is presented to associate cosmic dust particles with a known source. NASA JSC's Cosmic Dust Collection Program has made special attempts to collect dust from particular meteor showers and asteroid families when flights can be planned well in advance. However, it has rarely been possible to make collections on very short notice. In 2012, the Draconid meteor shower presented that opportunity. The Draconid meteor shower, originating from Comet 21P/Giacobini-Zinner, has produced both outbursts and storms several times during the last century, but the 2012 event was not predicted to be much of a show. Because of these predictions, the Cosmic Dust team had not targeted a stratospheric collection effort for the Draconids, despite the fact that they have one of the slowest atmospheric entry velocities (23 km/s) of any comet shower, and thus offer significant possibilities of successful dust capture. However, radar measurements obtained by the Canadian Meteor Orbit Radar during the 2012 Draconids shower indicated a meteor storm did occur October 8 with a peak at 16:38 (+/-5 min) UTC for a total duration of approximately 2 hours.

  13. Water Reservoirs in Small Planetary Bodies: Meteorites, Asteroids, and Comets

    Science.gov (United States)

    Alexander, Conel M. O'D.; McKeegan, Kevin D.; Altwegg, Kathrin

    2018-02-01

    Asteroids and comets are the remnants of the swarm of planetesimals from which the planets ultimately formed, and they retain records of processes that operated prior to and during planet formation. They are also likely the sources of most of the water and other volatiles accreted by Earth. In this review, we discuss the nature and probable origins of asteroids and comets based on data from remote observations, in situ measurements by spacecraft, and laboratory analyses of meteorites derived from asteroids. The asteroidal parent bodies of meteorites formed ≤ 4 Ma after Solar System formation while there was still a gas disk present. It seems increasingly likely that the parent bodies of meteorites spectroscopically linked with the E-, S-, M- and V-type asteroids formed sunward of Jupiter's orbit, while those associated with C- and, possibly, D-type asteroids formed further out, beyond Jupiter but probably not beyond Saturn's orbit. Comets formed further from the Sun than any of the meteorite parent bodies, and retain much higher abundances of interstellar material. CI and CM group meteorites are probably related to the most common C-type asteroids, and based on isotopic evidence they, rather than comets, are the most likely sources of the H and N accreted by the terrestrial planets. However, comets may have been major sources of the noble gases accreted by Earth and Venus. Possible constraints that these observations can place on models of giant planet formation and migration are explored.

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

    NARCIS (Netherlands)

    Frantseva, K.; Mueller, M.; van der Tak, F. F. S.; ten Kate, I. L.; Greenstreet, S.

    2017-01-01

    Preliminary results show that the asteroid-borne organic flux on Mars is comparable to the IPD rate; asteroids certainly cannot be neglected. Comets, on the other hand, contribute only 0.01% of the IDP-borne rate and can be neglected in the process of organic delivery to Mars.

  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. Meteor Showers.

    Science.gov (United States)

    Kronk, Gary W.

    1988-01-01

    Described are the history, formation, and observing techniques of meteors and comets. Provided are several pictures, diagrams, meteor organizations and publications, and meteor shower observation tables. (YP)

  17. 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.

  18. Asteroid-comet continuum objects in the solar system.

    Science.gov (United States)

    Hsieh, Henry H

    2017-07-13

    In this review presented at the Royal Society meeting, 'Cometary science after Rosetta', I present an overview of studies of small solar system objects that exhibit properties of both asteroids and comets (with a focus on so-called active asteroids). Sometimes referred to as 'transition objects', these bodies are perhaps more appropriately described as 'continuum objects', to reflect the notion that rather than necessarily representing actual transitional evolutionary states between asteroids and comets, they simply belong to the general population of small solar system bodies that happen to exhibit a continuous range of observational, physical and dynamical properties. Continuum objects are intriguing because they possess many of the properties that make classical comets interesting to study (e.g. relatively primitive compositions, ejection of surface and subsurface material into space where it can be more easily studied, and orbital properties that allow us to sample material from distant parts of the solar system that would otherwise be inaccessible), while allowing us to study regions of the solar system that are not sampled by classical comets.This article is part of the themed issue 'Cometary science after Rosetta'. © 2017 The Author(s).

  19. Predictions of the meteor radiant point associated with a comet

    International Nuclear Information System (INIS)

    Hasegawa, Ichiro

    1990-01-01

    Under the condition of equal heliocentric distances on the ecliptic plane, predictions of cometary meteor orbit and its radiant point are presented and discussed in terms of meteor observations. Some adjustment methods regarding the parent cometary orbit in order to fulfill the proposed conditions for the apparition of meteor streams are also presented. (author)

  20. Weird comets and asteroids the strange little worlds of the sun's family

    CERN Document Server

    Seargent, David A J

    2017-01-01

    This book concentrates on some of the odd aspects of comets and asteroids. Strange behavior of comets, such as outbursts and schisms, and how asteroids can temporally act as comets are discussed, together with the possible threat of Centaurs-class objects like the Taurid complex. Recent years have seen the distinction between comets and asteroids become less prominent. Comets in "asteroid" orbits and vice versa have become almost commonplace and a clearer view of the role of small bodies in the formation of the Solar System and their effect on Earth has become apparent. Seargent covers this development in detail by including new data and information from space probes. .

  1. Near-Earth Asteroids as Possible Parent Bodies of Meteor Streams

    Directory of Open Access Journals (Sweden)

    M.G. Sokolova

    2016-12-01

    Full Text Available The genetic relationship of meteor streams with near-Earth asteroids (NEAs is being actively studied. A genetic link with the asteroid is possible only for streams in which meteoroids have the geocentric speed smaller than 50 km/s, thereby meaning the proportionality of their orbits with the orbits of asteroids. To date, there are about 40 such orphan streams with unknown parent bodies. In the paper, NEA groups (Aten, Apollo, Amor, and Atira have been considered from the perspective of possible search for the parent bodies of meteor streams among them. The groups have been compared based on the following parameters: eccentricity of asteroid orbits, as well as size and chemical composition of asteroids. Currently, it is considered that the surface of asteroids with elongated orbits is subjected to temperature fall: it is heated in perihelion and cooled in aphelion. Due to small orbital periods around the Sun (about 2–4 years, this may lead to formation of meteoroid clusters. Therefore, comparison of asteroids by their orbit shape and physicochemical parameters enables us to distinguish between NEA groups of asteroids and the Apollo group as most probable candidates to search for the parent bodies of meteor streams among NEAs. Unfortunately, finding physicochemical parameters poses great difficulties, since they are only detectable for some asteroids. At the same time, it is impossible to study asteroids dynamics, evolution, and relation with other bodies of the Solar system, as well as to realistically assess the impact of NEAs and products of their disintegration collision with the Earth and to develop systems of anti-asteroid protection without knowing the following parameters of asteroids: mineralogical composition, density, size, and accurate mass.

  2. Laboratory Studies of Cometary Materials - Continuity Between Asteroid and Comet

    Science.gov (United States)

    Messenger, Scott; Walker, Robert M.

    2015-01-01

    Laboratory analysis of cometary samples have been enabled by collection of cometary dust in the stratosphere by high altitude aircraft and by the direct sampling of the comet Wild-2 coma by the NASA Stardust spacecraft. Cometary materials are composed of a complex assemblage of highly primitive, unprocessed interstellar and primordial solar system materials as well as a variety of high temperature phases that must have condensed in the inner regions of the protoplanetary disk. These findings support and contradict conclusions of comet properties based solely on astronomical observations. These sample return missions have instead shown that there is a continuity of properties between comets and asteroids, where both types of materials show evidence for primitive and processed materials. Furthermore, these findings underscore the importance and value of direct sample return. There will be great value in comparing the findings of the Stardust cometary coma sample return mission with those of future asteroid surface sample returns OSIRIS-REx and Hayabusa II as well as future comet nucleus sample returns.

  3. Comets, Asteroids, Meteorites, and the Origin of the Biosphere

    Science.gov (United States)

    Hoover, Richard B.

    2006-01-01

    During the past few decades, the delivery of water, organics, and prebiotic chemicals to the Biosphere of Earth during the Hadean (4.5-3.8 Ga) period of heavy bombardment by comets and asteroids has become more widely accepted. Comets are still largely regarded as frigid, pristine bodies of protosolar nebula material that are devoid of liquid water and therefore unsuitable for life. Complex organic compounds have been observed in comets and on the water-rich asteroid 1998 KY26 and near IR observations have indicated the presence of crystalline water ice and ammonia hydrate on the large Kuiper Belt object (50000) Quaoar that has resurfacing suggesting cryovolcanic outgassing. Spacecraft observations of the chemical compositions and characteristics of the nuclei of several comets (Halley, Borrelly, Wild 2, and Tempel 1) have shown that comets contain complex organic chemicals; that water is the predominant volatile; and that extremely high temperatures (approx. 350-400 K) can be reached on the surfae of the very black (albedo approx. 0.03) nuclei of comets when they approach the Sun. Impact craters and pinnacles observed on comet Wild 2 suggest a thick crust. Episodic outbursts and jets from the nuclei of several comets indicate that localized regimes of liquid water and water vapor can periodically exist beneath the comet crust. The Deep Impact mission found the temperature of the nucleus of comet Tempel 1 at 1.5 AU varied from a minimum of 280 plus or minus 8 K the 330K (57 C) on the sunlit side. In this paper it is argued that that pools and films of liquid water exist (within a wide range of temperatures) in cavities and voids just beneath the hot, black crust. The possibility of liquid water existing over a wide range of temperatures significantly enhances the possibility that comets might contain niches suitable for the growth of microbial communities and ecosystems. These regimes would be ideal for the growth of psychrophilic, mesophilic, and thermophilic

  4. The total mass and structure of the meteor stream associated with Comet Halley

    International Nuclear Information System (INIS)

    Hajduk, A.

    1982-01-01

    The meteor stream associated with Comet Halley has been studied by the author on the basis of a long series of visual and radar observations during the Eta Aquarid and Orionid meteor shower periods. It appeared that the stream exhibited inhomogeneities in both directions, across it and along the orbit. A stable zone of higher density and variable filaments have been detected. The total mass of the stream was determined at 5x10 14 kg. (Auth.)

  5. Comets, Asteroids, and the Origin of the Biosphere

    Science.gov (United States)

    Hoover, Richard B.

    2006-01-01

    During the past few decades, the role of comets in the delivery of water, organics, and prebiotic chemicals to the Biosphere of Earth during the Hadean (4.5-3.8 Ga) period of heavy bombardment has become more widely accepted. However comets are still largely regarded as frigid, pristine bodies of protosolar nebula material that are entirely devoid of liquid water and consequently unsuitable for life in any form. Complex organic compounds have been observed comets and on the water rich asteroid 1998 KY26, which has color and radar reflectivity similar to the carbonaceous meteorites. Near infrared observations have indicated the presence of crystalline water ice and ammonia hydrate on the large Kuiper Belt object (50000) Quaoar with resurfacing that may indicate cryovolcanic outgassing and the Cassini spacecraft has detected water-ice geysers on Saturn s moon Enceladus. Spacecraft observations of the chemical compositions and characteristics of the nuclei of several comets (Halley, Borrelly, Wild 2, and Tempel 1) have now firmly established that comets contain a suite of complex organic chemicals; water is the predominant volatile; and that extremely high temperatures (approx.350-400 K) can be reached on the surface of the very black (albedo-0.03) nuclei when the comets are with 1.5 AU from the Sun. Impact craters and pinnacles observed on comet Wild 2 suggest a thick crust and episodic outbursts and jets observed on the nuclei of several comets are interpreted as indications that localized regimes of liquid water and water vapor can periodically exist beneath the crust of some comets. The Deep Impact observations indicate that the temperature on the nucleus of of comet Tempel 1 at 1.5 AU varied from 330K on the sunlit side to a minimum of 280+/-8 K. It is interesting that even the coldest region of the comet surface was slightly above the ice/liquid water phase transition temperature. These results suggest that pools and films of liquid water can exist in a wide

  6. 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.

  7. The asteroid-comet continuum from laboratory and space analyses of comet samples and micrometeorites

    Science.gov (United States)

    Engrand, Cecile; Duprat, Jean; Bardin, Noemie; Dartois, Emmanuel; Leroux, Hugues; Quirico, Eric; Benzerara, Karim; Rémusat, Laurent; Dobrică, Elena; Delauche, Lucie; Bradley, John; Ishii, Hope; Hilchenbach, Martin; COSIMA Team

    2015-08-01

    Comets are probably the best archives of the nascent solar system, 4.5 Gyr ago, and their compositions reveal crucial clues on the structure and dynamics of the early protoplanetary disk. Anhydrous minerals (olivine and pyroxene) have been identified in cometary dust for a few decades. Surprisingly, samples from comet Wild2 returned by the Stardust mission in 2006 also contain high temperature mineral assemblages like chondrules and refractory inclusions, which are typical components of primitive meteorites (carbonaceous chondrites - CCs). A few Stardust samples have also preserved some organic matter of comet Wild 2 that share some similarities with CCs. Interplanetary dust falling on Earth originate from comets and asteroids in proportions to be further constrained. These cosmic dust particles mostly show similarities with CCs, which in turn only represent a few percent of meteorites recovered on Earth. At least two (rare) families of cosmic dust particles have shown strong evidences for a cometary origin: the chondritic porous interplanetary dust particles (CP-IDPs) collected in the terrestrial stratosphere by NASA, and the ultracarbonaceous Antarctic Micrometeorites (UCAMMs) collected from polar snow and ice by French and Japanese teams. The Rosetta mission currently carries dust analyzers capable of measuring dust flux, sizes, physical properties and compositions of dust particles from the Jupiter family comet 67P/Churyumov-Gerasimenko (COSIMA, GIADA, MIDAS), as well as gas analyzers (ROSINA, PTOLEMY, COSAC). A growing number of evidences highlights the existence of a continuum between asteroids and comets, already in the early history of the solar system. We will present the implications of the analyses of samples in the laboratory and in space to a better understanding of the early protoplanetary disk.

  8. Perspectives on Comets, Comet-like Asteroids, and Their Predisposition to Provide an Environment That Is Friendly to Life.

    Science.gov (United States)

    Bosiek, Katharina; Hausmann, Michael; Hildenbrand, Georg

    2016-04-01

    In recent years, studies have shown that there are many similarities between comets and asteroids. In some cases, it cannot even be determined to which of these groups an object belongs. This is especially true for objects found beyond the main asteroid belt. Because of the lack of comet fragments, more progress has been made concerning the chemical composition of asteroids. In particular, the SMASSII classification establishes a link between the reflecting spectra and chemical composition of asteroids and meteorites. To find clues for the chemical structure of comets, the parameters of all known asteroids of the SMASSII classification were compared to those of comet groups like the Encke-type comets, the Jupiter-family comets, and the Halley-type comets, as well as comet-like objects like the damocloids and the centaurs. Fifty-six SMASSII objects similar to comets were found and are categorized as comet-like asteroids in this work. Aside from the chemistry, it is assumed that the available energy on these celestial bodies plays an important role concerning habitability. For the determination of the available energy, the effective temperature was calculated. Additionally, the size of these objects was considered in order to evaluate the possibility of a liquid water core, which provides an environment that is more likely to support processes necessary to create the building blocks of life. Further study of such objects could be notable for the period of the Late Heavy Bombardment and could therefore provide important implications for our understanding of the inner workings of the prebiotic evolution within the Solar System since the beginning.

  9. Comet Hunters: A Citizen Science Project to Search for Comets in the Main Asteroid Belt

    Science.gov (United States)

    Hsieh, Henry H.; Schwamb, Megan Elizabeth; Zhang, Zhi-Wei; Chen, Ying-Tung; Wang, Shiang-Yu; Lintott, Chris

    2016-10-01

    Fully automated detection of comets in wide-field surveys remains a challenge, as even highly successful comet-finding surveys like Pan-STARRS rely on a combination of both automated flagging algorithms and vetting by human eyes. To take advantage of the long-noted superiority of the human eye over computer algorithms in certain types of pattern recognition, particularly when dealing with a range of target morphologies of interest, we have created a citizen science website with the aim of allowing the general public to aid in the search for active asteroids, which are objects that occupy dynamically asteroidal orbits yet exhibit comet-like dust emission due to sublimation, impact disruption, rotational destabilization, or other effects. Located at comethunters.org, the Comet Hunters website was built using the Zooniverse Project Builder (https://www.zooniverse.org/lab), and displays images of known asteroids obtained either from archival data obtained between 1999 and 2014 by the Suprime-Cam wide-field imager mounted on the 8-m Subaru telescope on Mauna Kea in Hawaii, or more contemporary data obtained by the Hyper Suprime-Cam (HSC) wide-field imager also on the Subaru Telescope as part of the ongoing HSC Subaru Strategic Program (SSP) survey. By using observations from such a large-aperture telescope, most of which have never been searched for solar system objects, much less cometary ones, we expect that volunteers should be able to make genuinely scientifically significant discoveries, and also provide valuable insights into the potential and challenges of searching for comets in the LSST era. To date, over 13,000 registered volunteers have contributed 350,000 classifications. We will discuss the design and construction of the Comet Hunters website, and also discuss early results from the project.This work uses data generated via the Zooniverse.org platform, development of which was supported by a Global Impact Award from Google, and by the Alfred P. Sloan

  10. The “Main-Belt Comets” are not comets, nor active asteroids; they are temporary shaken asteroids

    Science.gov (United States)

    Tancredi, Gonzalo

    2015-08-01

    Several objects in asteroidal orbits have presented comaes and tails similar to the ones presented by comets for short period of times. There are at present 16 objects in this group. Several hypotheses have been proposed to explain the activity of this object [Jewitt 2012]. Among them, the most accepted scenario for many objects is the ice sublimation and the ejection of dust, in a similar way as the cometary activity. Therefore several authors have coined these objects “Main Belt Comets” [Hsieh & Jewitt 2006]. Nevertheless, in some cases, some authors have concluded that the ejection of dust must be due to an impact.We propose an alternative model for the formation of the dusty comaes and tails.The impact of a small body against a larger one initially produces a crater and the ejection of dust at high velocity (>100 m/s). The dust is rapidly dispersed and it should be only observable just after the impact. In addition the impact generates a shock wave, which propagates to the body interior. The asteroid is globally shaken. Material is ejected at low velocities from the entire surface, similar to the low escape velocities at the surface. The particles move away from the asteroid due to the solar radiation pressure, forming the thin tails aligned with the orbital plane. These tails could persist for various months, as they have been seen in these objects.In addition, chunks of rock could be ejected in suborbital flights lasting for days; which, at return they would induce a new low-velocity ejection of particles. This process can explain some of the long-lasting events.The recurrence of the activity for some objects could be explained due to the collision with a dense meteor shower present in the main-belt.The so-called “Main Belt Comets” could be explained with a hypothesis that does not require the presence of ice on the surface of these objects. We also do not favor the term “Activated asteroids”, because it implies some kind of endogenous process

  11. Dawn of small worlds dwarf planets, asteroids, comets

    CERN Document Server

    Moltenbrey, Michael

    2016-01-01

    This book gives a detailed introduction to the thousands and thousands of smaller bodies in the solar system. Written for interested laymen, amateur astronomers and students it describes the nature and origin of asteroids, dwarf planets and comets, and gives detailed information about their role in the solar system. The author nicely reviews the history of small-world-exploration and describes past, current and future space craft missions studying small worlds, and presents their results. Readers will learn that small solar system worlds have a dramatically different nature and appearance than the planets. Even though research activity on small worlds has increased in the recent past many of their properties are still in the dark and need further research.

  12. Interception of comets and asteroids on collision course with earth

    Energy Technology Data Exchange (ETDEWEB)

    Solem, J.C.

    1992-03-01

    I derive expressions for the weight and range of applicability of interceptors capable of deflecting a comet or asteroid on collision course with Earth. The expressions use a fairly general relationship between the energy deposited and the mass of material blown off the astral assailant. To assess the probability that the astral assailant will fracture, I also calculate the fraction of the astral assailant`s mass that will be blown off. The interaction is calculated for both kinetic-energy deflection and nuclear-explosive deflection. In the nuclear-explosive case, I calculate the interceptor mass and cratering effect for detonations above the surface and below the surface as well as directly on the surface of the astral assailant. Because the wide range of densities and material properties that the astral assailant may possess, the principal value of this work is to show the relationships among the salient parameters of the problem.

  13. Comet and Asteroid Hazard to the Terrestrial Planets

    Science.gov (United States)

    Ipatov, S. I.; Mather, J. C.; Oegerle, William (Technical Monitor)

    2002-01-01

    We made computer simulations of orbital evolution for intervals of at least 5-10 Myr of N=2000 Jupiter-crossing objects (JCOs) with initial orbits close to those of real comets with period P less than 10 yr, 500 objects with orbits close to that of Comet 10P, and the asteroids initially located at the 3:1 and 5:2 resonances with Jupiter at initial eccentricity e(sub 0)=0.15 and initial inclination i(sub 0)=10(sup 0). The gravitational influence of all planets, except for Mercury and Pluto, was taken into account (without dissipative factors). We calculated the probabilities of collisions of bodies with the terrestrial planets, using orbital elements obtained with a step equal to 500 yr, and then summarized the results for all bodies, obtaining, the total probability Psigma of collisions with a planet and the total time interval Tsigma during which perihelion distance q of bodies was less than a semimajor axis of the planet. The values of p(sub r) =10(exp 6)Psigma/N and T(sub r)=T/1000 yr (where T=Tsigma/N) are presented in a table together with the ratio r of the total time interval when orbits were of Apollo type (at a greater than 1 AU, q less than 1.017 AU, e less than 0.999) to that of Amor type (1.017 less than q less than 1.33 AU), r(sub 2) is the same as r but for Apollo objects with e less than 0.9. For asteroids we present only results obtained by direct integration, as a symplectic method can give large errors for these resonances.

  14. Bangs and meteors from the quiet comet 15P/Finlay

    Czech Academy of Sciences Publication Activity Database

    Ye, Q.Z.; Brown, P. G.; Bell, Ch.; Gao, X.; Mašek, Martin; Hui, M.T.

    2015-01-01

    Roč. 814, č. 1 (2015), s. 1-10, č. článku 79. ISSN 0004-637X R&D Projects: GA MŠk(CZ) LG13007 EU Projects: European Commission(XE) 283783 - GLORIA Institutional support: RVO:68378271 Keywords : comets * 15P/Finlay * meteorites * meteors * meteoroids Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics OBOR OECD: Astronomy (including astrophysics,space science) Impact factor: 5.909, year: 2015

  15. Comets, Asteroids and Rubble Piles: not just debris

    Science.gov (United States)

    Harold, J. B.; Dusenbery, P.

    2010-12-01

    The National Center for Interactive Learning at the Space Science Institute (NCIL @ SSI) is developing a variety of asteroids related education activities as part of several E/PO projects, including Finding NEO (funded through NSF and NASA SMD); Great Balls of Fire! (funded through NSF); and a partnership with the WISE (Wide-field Infrared Survey Explorer) mission. These activities range from a web site to traveling exhibits in three different sizes. The Killer Asteroids web site (www.killerasteroids.org) includes background information on comets and asteroids as well as a number of interactive activities and games. These include a game that compares the risk of death from an asteroid impact to other hazards; a game and video vignettes on the role of backyard astronomers in light curve research; a physics-based asteroid deflection game; and a Google Earth -based "drop a rock on your house" activity. In addition, the project is developing a small, portable exhibit suitable for use in libraries or visitors centers. Great Balls of Fire! includes two separate traveling exhibitions: a 3000 square foot exhibition for science centers, and a 500 square foot version for smaller venues. Both will begin national tours in the summer of 2011. The Great Balls of Fire! exhibit program includes a free Education Program for docents and educators, and an Outreach Program to amateur astronomers around the country through the Astronomical Society of the Pacific’s (ASP) Astronomy from the Ground Up program. The project will facilitate partnerships between host venues and local astronomy clubs that can interact with the public using a toolkit of activities developed by ASP. Great Balls of Fire! Represents a collaboration between scientists, educators, exhibit designers, graphic artists, evaluators, education researchers, and three teams of middle school students who acted as advisors. The project’s exhibit design firm is Jeff Kennedy Associates Inc. We will present a summary of the

  16. Thermal Infrared Spectroscopy of the Leonid Meteor Parent Body, Comet Tempel-Tuttle

    Science.gov (United States)

    Lynch, D. K.; Russell, R. W.; Sitko, M.

    1998-09-01

    We report 3 - 13 micron spectroscopyy of comet 55P/Tempel-Tuttle on Feb 8 and 9 1998 UT (roughly three weeks before perihelion) using the NASA Infrared Telescope Facility and The Aerospace Corporation Broadband Array Spectrograph System (BASS) with a 3.2 arc second diameter beam. The spectra on both nights were very similar (within the formal errors), suggesting little, if any, night-to-night variation. The spectra showed a relatively smooth continuum that was well-fit from 3 to 13 microns by a 330 K grey body. This is considerably higher than than the black body radiative equilibrium temperature of 273 K. Significant features (such as the crystalline olivine 11.3 micron feature seen in comet Hale-Bopp) were noticeably absent. This is only one of a very few comets that have exhibited this grey-body continuum type of spectral shape, and the implications of this shape (on particle size, composition, thermal history, for example) will be explored. Because the dust from this comet forms the Leonid meteors, its properties are of particular interest to the meteor and spacecraft communities.

  17. Dynamics of Dust Particles Released from Oort Cloud Comets and Their Contribution to Radar Meteors

    Science.gov (United States)

    Nesvorny, David; Vokrouhlicky, David; Pokorny, Petr; Janches, Diego

    2012-01-01

    The Oort Cloud Comets (OCCs), exemplified by the Great Comet of 1997 (Hale-Bopp), are occasional visitors from the heatless periphery of the solar system. Previous works hypothesized that a great majority of OCCs must physically disrupt after one or two passages through the inner solar system, where strong thermal gradients can cause phase transitions or volatile pressure buildup. Here we study the fate of small debris particles produced by OCC disruptions to determine whether the imprints of a hypothetical population of OCC meteoroids can be found in the existing meteor radar data. We find that OCC particles with diameters D or approx. 1 mm have a very low Earth-impact probability. The intermediate particle sizes, D approx. 100 microns represent a sweet spot. About 1% of these particles orbitally evolve by Poynting-Robertson drag to reach orbits with semimajor axis a approx. 1 AU. They are expected to produce meteors with radiants near the apex of the Earth s orbital motion. We find that the model distributions of their impact speeds and orbits provide a good match to radar observations of apex meteors, except for the eccentricity distribution, which is more skewed toward e approx. 1 in our model. Finally, we propose an explanation for the long-standing problem in meteor science related to the relative strength of apex and helion/antihelion sources. As we show in detail, the observed trend, with the apex meteors being more prominent in observations of highly sensitive radars, can be related to orbital dynamics of particles released on the long-period orbits.

  18. ExploreNEOs. VIII. Dormant Short-period Comets in the Near-Earth Asteroid Population

    NARCIS (Netherlands)

    Mommert, M.; Harris, A. W.; Müller, M.; Hora, J. L.; Trilling, D. E.; Bottke, W. F.; Thomas, C. A.; Delbo, M.; Emery, J. P.; Fazio, G.; Smith, H. A.

    2015-01-01

    We perform a search for dormant comets, asteroidal objects of cometary origin, in the near-Earth asteroid (NEA) population based on dynamical and physical considerations. Our study is based on albedos derived within the ExploreNEOs program and is extended by adding data from NEOWISE and the Akari

  19. Direct Characterization of Comets and Asteroids via Cosmic Dust Analysis from the Deep Space Gateway

    Science.gov (United States)

    Fries, M.; Fisher, K.

    2018-02-01

    The Deep Space Gateway can allow direct analysis of dust from over a dozen comets, using an instrument similar to the successful Cassini Dust Analyzer (CDA). Long-term measurements are preferred. Compositions of over a dozen asteroids and comets can be obtained.

  20. Orbit determination for the Mariner Mark II Comet Rendezvous/Asteroid Flyby mission - The orbiting phase

    Science.gov (United States)

    Weeks, C. J.

    1986-08-01

    The Comet Rendezvous/Asteroid Flyby (CRAF) mission is the first of the Mariner Mark II mission set, designed to explore the outer solar system. Major objectives of orbit determination will be determine the positions and masses of the comet and asteroid and the relative position of the spacecraft, which is important to accurate pointing of the scan platform on which the narrow angle camera and scientific instruments are positioned. Position prediction is also important, since continuous commuication with the spacecraft will not be possible. The small gravitational attractions and poorly known ephemerides of the comet and asteroid, and the small, slow spacecraft orbit about the comet, pose significant new problems for orbit determination. Results of simulations studying the effectiveness of key data types, the accuracies of estimates, and prediction capabilities, are presented.

  1. Distribution of Jupiter-family asteroids and comets in near-Earth space

    Science.gov (United States)

    Emel'yanenko, V.

    2012-09-01

    We analyze the orbital distribution of objects captured to near-Earth space from the flux of comets coming from the outer Solar system. For this purpose, we use the model of the cometary cloud developed earlier. This model is consistent with the broad dynamical characteristics of observed near-parabolic comets, short-period comets, Centaurs and higheccentricity trans-Neptunian objects. We show that the observed distribution of near-Earth objects moving in cometary orbits is different from the modelled distribution formed dynamically by the action of planetary perturbations. In particular, while the distributions of arguments of perihelion for observed Jupiter-family comets and modelled cometary objects follow a sinusoidal law with pronounced maxima around 0 and 180 degrees, it is not the case for the distribution of observed cometary asteroids. We discuss those factors which could lead to this inconsistency in the distribution of active Jupiter-family comets and asteroids in cometary orbits.

  2. Unveiling Clues from Spacecraft Missions to Comets and Asteroids through Impact Experiments

    Science.gov (United States)

    Lederer, Susan M.; Jensen, Elizabeth; Fane, Michael; Smith, Douglas; Holmes, Jacob; Keller, Lindasy P.; Lindsay, Sean S.; Wooden, Diane H.; Whizin, Akbar; Cintala, Mark J.; hide

    2016-01-01

    The Deep Impact Spacecraft mission was the first to boldly face the challenge of impacting the surface of a comet, 9P/Tempel 1, to investigate surface and subsurface 'pristine' materials. The Stardust mission to Comet 81P/Wild 2 brought back an exciting surprise: shocked minerals which were likely altered during the comet's lifetime. Signatures of shock in meteorites also suggest that the violent past of the solar system has left our small bodies with signatures of impacts and collisions. These results have led to the question: How have impacts affected the evolutionary path taken by comets and asteroids, and what signatures can be observed? A future planetary mission to a near-Earth asteroid is proposing to take the next steps toward understanding small bodies through impacts. The mission would combine an ESA led AIM (Asteroid Impact Mission) with a JHU/APL led DART (Double Asteroid Redirect Mission) spacecraft to rendezvous with binary near-Earth asteroid 65803 Didymus (1996 G2). DART would impact the smaller asteroid, 'Didymoon' while AIM would characterize the impact and the larger Didymus asteroid. With these missions in mind, a suite of experiments have been conducted at the Experimental Impact Laboratory (EIL) at NASA Johnson Space Center to investigate the effects that collisions may have on comets and asteroids. With the new capability of the vertical gun to cool targets in the chamber through the use of a cold jacket fed by liquid nitrogen, the effects of target temperature have been the focus of recent studies. Mg-rich forsterite and enstatite (orthopyroxene), diopside (monoclinic pyroxene) and magnesite (Mg-rich carbonate) were impacted. Target temperatures ranged from 25 deg to -100 deg, monitored by connecting thermocouples to the target container. Impacted targets were analyzed with a Fourier Transform Infrared Spectrometer (FTIR) and Transmission Electron Microscope (TEM). Here we present the evidence for impact-induced shock in the minerals through

  3. Preliminary Results of the Observations of a Meteor Shower of Comet C/2012 s1 (ison) in January 2014

    Science.gov (United States)

    Golubaev, A. V.; Bryukhanov, I. S.; Tabolich, A.; Tabolich, V.; Akulich, D.; Kulakovskaya, A.; Mechinsky, V. A.; Sergey, I. M.

    2014-05-01

    Dedicated researches on detection of possible meteoric activity in January 2014 connected with remains of comet C/2012 S1 (ISON) have been conducted. This work is based on the observational material obtained at different points of the Earth by means of 10 CCD cameras equipped with >-like lenses (> camera) and FM radio observations. 43 meteor events were revealed by viewing 54,000 images from 10 to 17 January 2014. As a result of position measurements of CCD images, coordinates of the meteor radiant were found: α_{R}=156°, δ_{R}=+38°. During this period (January 08 to January 24, 2014) an increase in the meteor activity above the level of the sporadic meteor background has been confirmed by FM-radio observations in Molodechno (Belarus) and Jaen (Spain)

  4. Preliminary results of observations in January, 2014 of a meteor shower of comet C/2012 S1 (ISON)

    Science.gov (United States)

    Golubaev, A.; Brukhanov, I.; Tabolich, A.; Tabolich, T.; Kulakovskaya, A.; Sergey, I.

    2014-07-01

    Special research on the detection of possible meteoric activity in January 2014 connected with the remains of the comet C/2012 S1 (ISON) are conducted. This work is based on the observational material received in various points on the Earth, by means of CCD cameras (10 CCD cameras), equipped with lenses like ''Fish eye'' (All-sky camera) and radio observations in the FM range. 43 meteor phenomena were revealed during viewing of 54,000 images on January 17, 2014. As a result of position measurements of images and calculations coordinates of a meteor radiant were received: α_{R}=156 deg, δ_{R}= +38 deg (Fig. 1). During this period (January 08-24, 2014) increase of meteor activity over the level of a sporadic meteor background is confirmed by FM-radio observations in Molodechno (Belarus) and Jaen (Spain) (Fig. 2a,b).

  5. Telescopic and meteor observation of `Oumuamua, the first known interstellar asteroid

    Science.gov (United States)

    Ye, Quan-Zhi

    2018-04-01

    1I/2017 U1 ('Oumuamua), a recently discovered asteroid in a hyperbolic orbit, is the first macroscopic object of extrasolar origin identified in the solar system. I will present imaging and spectroscopic observations of 'Oumuamua as well as a search of meteor activity potentially linked to this object using the Canadian Meteor Orbit Radar. We find that 'Oumuamua exhibits a moderate spectral gradient of 10%+-6% per 100 nm, a value lower than that of outer solar system bodies, indicative of a formation and/or previous residence in a warmer environment. Imaging observation and spectral line analysis show no evidence that 'Oumuamua is presently active. Negative meteor observation is as expected, since ejection driven by sublimation of commonly known cometary species such as CO requires an extreme ejection speed of ~40 m/s at ~100 au in order to reach the Earth. No obvious candidate stars are proposed as the point of origin for 'Oumuamua. Given a mean free path of ~109 ly in the solar neighborhood, 'Oumuamua has likely spent a very long time in interstellar space before encountering the solar system.

  6. Meteor showers associated with the low-albedo Near-Earth Asteroid 2000 PG3

    Science.gov (United States)

    Babadzhanov, P. B.

    Using mid infrared and visible photometry, Fernandez et al. (2001) derived new effective radius and geometric albedo for NEO 2000 PG_3, moving on comet-like orbit, equal to 3.08 km and 0.021 accordingly. We investigated the orbital evolution of 2000 PG_3 under gravitational action of six planets (Mercury to Saturn) over one cycle of variation of perihelion argument. According to the method published (see e.g. Babadzhanov 2001), the theoretical geocentric radiants and velocities of four possible meteor showers associated with this object are determined. Using published data, the theoretically predicted showers are identified with the observed ones, namely, night-time Northern and Southern δ-Piscids, and associations 35 and 41 from the catalogue of Kashcheev et al. (1967). The character of the orbit and low albedo of 2000 PG_3, and the existence of observed meteor showers associated with 2000 PG_3 provide evidence supporting the conjecture that this object may be of cometary nature. References Babadzhanov, P.B. 2001, A&A 371, 329-335 Fernandez, Y.R., Jewitt, D.C., & Shepard, S.S. 2001, AphJ 553: L197-L200 Kashcheev, B.L., Lebedinets, V.N., & Lagutin, M.F. 1967, Meteoric Phenomena in the Earth atmosphere, Nauka. Moscow

  7. Collisional Histories of Comets and Trojan Asteroids: Insights from Forsterite and Enstatite Impact Studies

    Science.gov (United States)

    Lederer. S. M.; Jensen, E. A.; Wooden, D. H.; Lindsay, S. S.; Smith, D. C.; Cintala, M. J.; Nakamura-Messenger, K.; Keller, L. P.

    2012-01-01

    Impacts into forsterite and orthoenstatite at speeds typically encountered by comets demonstrate that shock imparted by collisions is detectable in the infrared signatures of their dust. The spectral signatures can be traced to physical alterations in their crystalline structures, as observed in TEM imaging and modeled using a dipole approximation. These results yield tantalizing insights into the collisional history of our solar system, as well as the history of individual comets and Trojan asteroids.

  8. Understanding the Effects of Collisional Evolution and Spacecraft Impact Experiments on Comets and Asteroids

    Science.gov (United States)

    Lederer, S.M.; Jensen, E.A.; Fane, M.; Smith, D.C.; Holmes, J.; Keller, L.P.; Lindsay, S.S.; Wooden, D.H.; Whizin, A.; Cintala, M.J.; hide

    2017-01-01

    Comets and asteroids have endured impacts from other solar system bodies that result in outcomes ranging from catastrophic collisions to regolith evolution due to micrometeorid bombardment of the surface ices and refactory components. Experiments designed to better understand these relics of solar system formation have been conducted on Earth in a laboratory setting, as well as in space through, e.g., the Deep Impact Mission to Comet Tempel 1. Deep Impact fired a high-speed impactor into the roughly 6 km nucleus of the comet. The ejecta plume generated by the impact was studied by both spacecraft instrumentation and groundbased telescopes.

  9. Spectral investigation of two asteroidal fireballs

    Czech Academy of Sciences Publication Activity Database

    Borovička, Jiří

    2006-01-01

    Roč. 97, 3-4 (2006), s. 279-293 ISSN 0167-9295. [Asteroids, Comets, Meteors 2005. Búzios, 07.08.2005-12.08.2005] R&D Projects: GA ČR GA205/05/0543; GA ČR GA205/03/1404 Institutional research plan: CEZ:AV0Z10030501 Keywords : asteroids * meteors * spectroscopy Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 0.252, year: 2006

  10. Dust particles from comets and asteroids collected at the Earth's orbit: Parent-daughter relationships

    Science.gov (United States)

    Jackson, A. A.; Zook, H. A.

    1991-01-01

    The relative contributions of comets and asteroids to the reservoir of dust in the interplanetary medium is not well known. There are direct observations of dust released from comets and there is evidence to associate the IRAS dust bands with possible collisions of Asteroids in the main belt. It is believed that one may combine lab analysis of the physics and chemistry of captured particles with orbital data in order to identify comet and asteroid parent bodies. It is possible to use the collected orbits of the dust to connect with its source in two ways. One is to consider the long time orbit evolution of the dust under Poynting-Robertson drag. The other is to look at the prompt orbit change of dust from comets onto trajectories that intersect the earth's orbit. In order to characterize the orbits of dust particles evolved over a long period of time, a study of its orbital evolution was undertaken. Various parameters associated with these dust orbits as they cross the Earth's orbit were considered in order to see if one may discriminate between particles evolved from comets and asteroids. The method was to calculate by a numerical procedure the orbits of dust particles after they left their parent bodies. It appears that as the particles pass the Earth's orbit, asteroidal grains and cometary grains can be differentiated on the basis of their measured orbital eccentricities even after much planetary perturbation. Broad parent daughter associations can be made on this basis from measurement of their trajectories intercepted in earth orbit.

  11. Potential Jupiter-Family comet contamination of the main asteroid belt

    Science.gov (United States)

    Hsieh, Henry H.; Haghighipour, Nader

    2016-10-01

    We present the results of "snapshot" numerical integrations of test particles representing comet-like and asteroid-like objects in the inner Solar System aimed at investigating the short-term dynamical evolution of objects close to the dynamical boundary between asteroids and comets as defined by the Tisserand parameter with respect to Jupiter, TJ (i.e., TJ = 3). As expected, we find that TJ for individual test particles is not always a reliable indicator of initial orbit types. Furthermore, we find that a few percent of test particles with comet-like starting elements (i.e., similar to those of Jupiter-family comets) reach main-belt-like orbits (at least temporarily) during our 2 Myr integrations, even without the inclusion of non-gravitational forces, apparently via a combination of gravitational interactions with the terrestrial planets and temporary trapping by mean-motion resonances with Jupiter. We estimate that the fraction of real Jupiter-family comets occasionally reaching main-belt-like orbits on Myr timescales could be on the order of ∼ 0.1-1%, although the fraction that remain on such orbits for appreciable lengths of time is certainly far lower. For this reason, the number of JFC-like interlopers in the main-belt population at any given time is likely to be small, but still non-zero, a finding with significant implications for efforts to use apparently icy yet dynamically asteroidal main-belt comets as tracers of the primordial distribution of volatile material in the inner Solar System. The test particles with comet-like starting orbital elements that transition onto main-belt-like orbits in our integrations appear to be largely prevented from reaching low eccentricity, low inclination orbits, suggesting that the real-world population of main-belt objects with both low eccentricities and inclinations may be largely free of this potential occasional Jupiter-family comet contamination. We therefore find that low-eccentricity, low-inclination main

  12. Unveiling clues from Spacecraft Missions to Comets and Asteroids through Impact Experiments

    Science.gov (United States)

    Lederer, Susan M.; Jensen, Elizabeth; Fane, Michael; Smith, Douglas; Holmes, Jacob; Keller, Lindsay P.; Lindsay, Sean S.; Wooden, Diane H.; Whizin, Akbar; Cintala, Mark J.; Zolensky, Michael

    2016-10-01

    The Deep Impact Spacecraft mission was the first to boldly face the challenge of impacting the surface of a comet, 9P/Tempel 1, to investigate surface and subsurface 'pristine' materials. The Stardust mission to Comet 81P/Wild 2 brought back an exciting surprise: shocked minerals which were likely altered during the comet's lifetime. Signatures of shock in meteorites also suggest that the violent past of the solar system has left our small bodies with signatures of impacts and collisions. These results have led to the question: How have impacts affected the evolutionary path taken by comets and asteroids, and what signatures can be observed?A future planetary mission to a near-Earth asteroid is proposing to take the next steps toward understanding small bodies through impacts. The mission would combine an ESA led AIM (Asteroid Impact Mission) with a JHU/APL led DART (Double Asteroid Redirect Mission) spacecraft to rendezvous with binary near-Earth asteroid 65803 Didymus (1996 G2). DART would impact the smaller asteroid, 'Didymoon' while AIM would characterize the impact and the larger Didymus asteroid.With these missions in mind, a suite of experiments have been conducted at the Experimental Impact Laboratory (EIL) at NASA Johnson Space Center to investigate the effects that collisions may have on comets and asteroids. With the new capability of the vertical gun to cool targets in the chamber through the use of a cold jacket fed by liquid nitrogen, the effects of target temperature have been the focus of recent studies. Mg-rich forsterite and enstatite (orthopyroxene), diopside (monoclinic pyroxene) and magnesite (Mg-rich carbonate) were impacted. Target temperatures ranged from 25°C to -100°C, monitored by connecting thermocouples to the target container. Impacted targets were analyzed with a Fourier Transform Infrared Spectrometer (FTIR) and Transmission Electron Microscope (TEM). Here we present the evidence for impact-induced shock in the minerals through

  13. Challenges of deflecting an asteroid or comet nucleus with a nuclear burst

    Energy Technology Data Exchange (ETDEWEB)

    Bradley, Paul A [Los Alamos National Laboratory; Plesko, Cathy S [Los Alamos National Laboratory; Clement, Ryan R. C. [Los Alamos National Laboratory; Conlon, Le Ann M [Los Alamos National Laboratory; Weaver, Robert P [Los Alamos National Laboratory; Guzik, Joyce A [Los Alamos National Laboratory; Pritchett - Sheets, Lori A [Los Alamos National Laboratory; Huebner, Walter F [SWRI

    2009-01-01

    There are many natural disasters that humanity has to deal with over time. These include earthquakes, tsunamis, hurricanes, floods, asteroid strikes, and so on. Some of these disasters occur slowly enough that some advance warning is possible for affected areas. In this case, the response is to evacuate the affected area and deal wilh the damage later. The Katrina and Rita hurricane evacuations on the U.S. Gulf Coasl in 2005 demonstrated the chaos that can result from such a response. In contrast with other natural disasters, it is likely that an asteroid or comet nucleus on a collision course with Earth will be detected with enough warning time to possibly deflect it away. Thanks to Near-Earth Object (NED) surveys, people are working towards a goal of cataloging at least 90% of all near-Earth objects with diameters larger than {approx} 140 meters in the next fifteen years. The important question then, is how to mitigate the threat from an asteroid or comet nucleus found to be on a collision course with Earth. In this paper. we briefly review some possible deflection methods, describe their good and bad points, and then embark on a more detailed description of using nuclear munitions in a standoff mode to deflect the asteroid or comet nucleus before it can hit Earth.

  14. 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.

  15. Evidence of Collisional Histories of Asteroids, Comets and Meteorites: Comparisons with Shocked Minerals

    Science.gov (United States)

    Lederer, Susan M.; Jensen, Elizabeth; Smith, Douglas; Fane, Michael; Whizin, Akbar; Landsman, Zoe A.; Wooden, Diane H.; Lindsay, Sean S.; Cintala, Mark; Keller, Lindsay P.; hide

    2017-01-01

    Evidence of the collisional history of comets and asteroids has been emerging from analyses of cometary forsterite and enstatite returned from Comet Wild 2 by the Stardust mission (Keller et al.Geochim. Cosmochim. Acta 72, 2008; Tomeoka et al. MAPS 43, 2008; Jacobs et al. MAPS 44, 2009). Likewise, shock metamorphism is observed in many meteoritic forsterites and enstatites (McCausland et al. AGU, 2010), suggesting similar collisional histories for asteroids. Further exploration of the effects of collisions is slated for the upcoming Asteroid Impact Mission/Double Asteroid Redirection Test (AIM/DART) mission, expected for launch in 2020. DART will impact Didymoon, the companion of the larger 65803 Didymos (1996 G2) asteroid, and AIM will use its instrumentation to characterize the impact. A suite of relevant impact experiments have been carried out in the Experimental Impact Laboratory at the NASA Johnson Space Center at velocities ranging from approx. 2.0 - 2.8 km/s and temperatures from 25 C to -100 C. Targets include a suite of minerals typically found in cometary dust and in asteroids and meteorites: Mg-rich forsterite (olivine), enstatite (orthopyroxene), diopside (clinopyroxene), magnesite (Mg-rich carbonate), and serpentine (phyllosilicate). Transmission Electron Microscope (TEM) imaging indicates evidence of shock similar to that seen in forsterite and enstatite from Comet Wild 2. Fourier Transform Infrared (FTIR) Spectroscopy will also be used for comparisons with meteorite spectra. A quantitative analysis of the shock pressures required to induce planar dislocations and spectral effects with respect to wavelength will also be presented.

  16. Protecting Earth from comet/asteroid impacts through international cooperation: Issues & current status

    Energy Technology Data Exchange (ETDEWEB)

    Tedeschi, W.

    1994-05-01

    Compelling evidence of a catastrophic asteroid impact on Earth 65 million years ago has given rise to international discussions about the probability, consequences, and prevention of future impacts. Because asteroid and comet impacts pose a grave danger to all humanity, preventive defensive measures should appropriately be based on international cooperation and action. Action may consist of detection research, experimentation to prevent the impact, public education on the issues, emergency planning, and actual protection if required. This paper provides background information on the threat posed by Near-Earth Objects (NEOs) and discusses associated technical and geopolitical issues and the current status of some related international activities.

  17. Looking before we leap: an ongoing, quantative investigation of asteroid and comet impact hazard mitigation

    Energy Technology Data Exchange (ETDEWEB)

    Plesko, Catherine S [Los Alamos National Laboratory; Weaver, Robert P [Los Alamos National Laboratory; Bradley, Paul A [Los Alamos National Laboratory; Huebner, Walter F [Los Alamos National Laboratory

    2010-01-01

    There are many outstanding questions about the correct response to an asteroid or comet impact threat on Earth. Nuclear munitions are currently thought to be the most efficient method of delivering an impact-preventing impulse to a potentially hazardous object (PHO). However, there are major uncertainties about the response of PHOs to a nuclear burst, and the most appropriate ways to use nuclear munitions for hazard mitigation.

  18. Low-Energy Asteroid and Comet Transit Analysis using Isolating Blocks

    Science.gov (United States)

    Anderson, Rodney L.; Chodas, Paul; Easton, Robert W.; Lo, Martin W.

    2016-05-01

    It is well known that asteroids and comets typically capture or transit near a planet by traveling through the L1 and L2 libration point gateways. These regions are therefore key to understanding the mechanism by which these captures, transits, and potential impacts occur. Recently, Anderson, Easton, and Lo (2015) explored the L2 region in the Earth-Moon system using isolating blocks in the circular restricted three-body problem (CRTBP). Isolating blocks provide a theoretically rigorous method for computing the invariant manifolds of libration point periodic orbits and all possible transit trajectories at a particular Jacobi constant in the CRTBP. Using isolating block methods allows us to directly compute and study the transit trajectories used by comets and asteroids in the low-energy regimes common for these types of bodies. In this study, both L1 and L2 isolating blocks are computed for the Sun-Earth and Sun-Jupiter CRTBP systems to compute trajectories transiting near the Earth and Jupiter. Statistics based on transit time, periapse passages, and exit location are first computed. Then individual trajectory solutions corresponding to different trajectory types are analyzed. The transit trajectories are also characterized using their orbital elements and compared to known comets and asteroids. These results show that the invariant manifolds of the orbits in the isolating block control and guide the dynamics of comets and asteroids as they temporarily capture between the L1 and L2 region of a planet or satellite.Reference: Anderson, R. L., R. W. Easton, M. W. Lo (2015), AAS/AIAA Astrodynamics Conf., AAS 15-615.

  19. Electrostatic forces on grains near asteroids and comets

    Directory of Open Access Journals (Sweden)

    Hartzell Christine

    2017-01-01

    Full Text Available Dust on and near the surface of small planetary bodies (e.g. asteroids, the Moon, Mars’ moons is subject to gravity, cohesion and electrostatic forces. Due to the very low gravity on small bodies, the behavior of small dust grains is driven by non-gravitational forces. Recent work by Scheeres et al. has shown that cohesion, specifically van der Waals force, is significant for grains on asteroids. In addition to van der Waals cohesion, dust grains also experience electrostatic forces, arising from their interaction with each other (through tribocharging and the solar wind plasma (which produces both grain charging and an external electric field. Electrostatic forces influence both the interactions of grains on the surface of small bodies as well as the dynamics of grains in the plasma sheath above the surface. While tribocharging between identical dielectric grains remains poorly understood, we have recently expanded an existing charge transfer model to consider continuous size distributions of grains and are planning an experiment to test the charge predictions produced. Additionally, we will present predictions of the size of dust grains that are capable of detaching from the surface of small bodies.

  20. Internal gravity, self-energy, and disruption of comets and asteroids

    Science.gov (United States)

    Dobrovolskis, Anthony R.; Korycansky, D. G.

    2018-03-01

    The internal gravity and self-gravitational energy of a comet, asteroid, or small moon have applications to their geophysics, including their formation, evolution, cratering, and disruption, the stresses and strains inside such objects, sample return, eventual asteroid mining, and planetary defense strategies for potentially hazardous objects. This paper describes the relation of an object's self-energy to its collisional disruption energy, and shows how to determine an object's self-energy from its internal gravitational potential. Any solid object can be approximated to any desired accuracy by a polyhedron of sufficient complexity. An analytic formula is known for the gravitational potential of any homogeneous polyhedron, but it is widely believed that this formula applies only on the surface or outside of the object. Here we show instead that this formula applies equally well inside the object. We have used these formulae to develop a numerical code which evaluates the self-energy of any homogeneous polyhedron, along with the gravitational potential and attraction both inside and outside of the object, as well as the slope of its surface. Then we use our code to find the internal, external, and surface gravitational fields of the Platonic solids, asteroid (216) Kleopatra, and comet 67P/Churyumov-Gerasimenko, as well as their surface slopes and their self-gravitational energies. We also present simple spherical, ellipsoidal, cuboidal, and duplex models of Kleopatra and comet 67P, and show how to generalize our methods to inhomogeneous objects and magnetic fields. At present, only the self-energies of spheres, ellipsoids, and cuboids (boxes) are known analytically (or semi-analytically). The Supplementary Material contours the central potential and self-energy of homogeneous ellipsoids and cuboids of all aspect ratios, and also analytically the self-gravitational energy of a "duplex" consisting of two coupled spheres. The duplex is a good model for "contact binary

  1. Cartography of asteroids and comet nuclei from low resolution data

    Science.gov (United States)

    Stooke, Philip J.

    1992-01-01

    High resolution images of non-spherical objects, such as Viking images of Phobos and the anticipated Galileo images of Gaspra, lend themselves to conventional planetary cartographic procedures: control network analysis, stereophotogrammetry, image mosaicking in 2D or 3D, and airbrush mapping. There remains the problem of a suitable map projection for bodies which are extremely elongated or irregular in shape. Many bodies will soon be seen at lower resolution (5-30 pixels across the disk) in images from speckle interferometry, the Hubble Space Telescope, ground-based radar, distinct spacecraft encounters, and closer images degraded by smear. Different data with similar effective resolutions are available from stellar occultations, radar or lightcurve convex hulls, lightcurve modeling of albedo variations, and cometary jet modeling. With such low resolution, conventional methods of shape determination will be less useful or will fail altogether, leaving limb and terminator topography as the principal sources of topographic information. A method for shape determination based on limb and terminator topography was developed. It has been applied to the nucleus of Comet Halley and the jovian satellite Amalthea. The Amalthea results are described to give an example of the cartographic possibilities and problems of anticipated data sets.

  2. The impact imperative: Laser ablation for deflecting asteroids, meteoroids, and comets from impacting the earth

    International Nuclear Information System (INIS)

    Campbell, Jonathan W.; Phipps, Claude; Smalley, Larry; Reilly, James; Boccio, Dona

    2003-01-01

    Impacting at hypervelocity, an asteroid struck the Earth approximately 65 million years ago in the Yucatan Peninsula area. This triggered the extinction of almost 70% of the species of life on Earth including the dinosaurs. Other impacts prior to this one have caused even greater extinctions. Preventing collisions with the Earth by hypervelocity asteroids, meteoroids, and comets is the most important immediate space challenge facing human civilization. This is the Impact Imperative. We now believe that while there are about 2000 earth orbit crossing rocks greater than 1 kilometer in diameter, there may be as many as 200,000 or more objects in the 100 m size range. Can anything be done about this fundamental existence question facing our civilization? The answer is a resounding yes! By using an intelligent combination of Earth and space based sensors coupled with an infra-structure of high-energy laser stations and other secondary mitigation options, we can deflect inbound asteroids, meteoroids, and comets and prevent them from striking the Earth. This can be accomplished by irradiating the surface of an inbound rock with sufficiently intense pulses so that ablation occurs. This ablation acts as a small rocket incrementally changing the shape of the rock's orbit around the Sun. One-kilometer size rocks can be moved sufficiently in about a month while smaller rocks may be moved in a shorter time span

  3. Physical Observations of 1996 PW and 1997 SE5: Extinct Comets or D-Type Asteroids?

    Science.gov (United States)

    Hicks, M. D.; Buratti, B. J.; Newburn, R. L.; Rabinowitz, D. L.

    2000-02-01

    The minor planets 1996 PW and 1997 SE5 are two of the few known asteroids with orbital elements typical of long-period and Jupiter-family comets and as such represent strong candidates for extinct cometary nuclei. We obtained filter photometry of 1996 PW and filter photometry and medium-resolution CCD spectroscopy of 1997 SE5 during their discovery apparitions. We also observed a suite of D-type asteroids as possible spectral analogs of cometary nuclei. Both 1996 PW and 1997 SE5 have moderately red, featureless spectra typical of the D-type asteroids, cometary nuclei, and other extinct cometary candidates. The photometry for 1997 SE5 was fit by a triple-peaked lightcurve with a period of 9.050±0.005 h and an amplitude of 0.4 magnitude, suggesting a relatively complex and elongated shape. With this work, 1997 SE5 and 1996 PW join the ranks of 3552 Don Quixote and 944 Hildago as established candidates for extinct comet nuclei.

  4. Ultraviolet Characterization of Comet and Asteroid Surfaces as Observed by the Rosetta Alice Instrument (Invited)

    Science.gov (United States)

    Feaga, L. M.; Holt, C. E.; Steffl, A.; Stern, S. A.; Bertaux, J. L.; Parker, J. W.; A'Hearn, M. F.; Feldman, P.; Keeney, B. A.; Knight, M. M.; Noonan, J.; Vervack, R. J., Jr.; Weaver, H. A., Jr.

    2017-12-01

    In 2016, Alice, NASA's lightweight and low-power far-ultraviolet (FUV) imaging spectrograph onboard ESA's comet-orbiting spacecraft Rosetta, completed a 2-year characterization of 67P/Churyumov-Gerasimenko (C-G), a bi-lobed Jupiter family comet with extreme seasons and diverse surface features. In addition to coma studies, Alice monitored the sunlit surface of C-G from 700-2050 Å to establish the FUV bidirectional reflectance properties and albedo of the surface, determine homogeneity, correlate spectral features with morphological regions, and infer the compositional makeup of the comet. The heliocentric distance coverage (3.7 AU from the Sun, through perihelion at 1.24 AU, and back out to 3.8 AU) over a period of 2 years and spatial resolution of the Alice data (e.g., 30 m by 150 m at the comet from a spacecraft distance of 30 km) resulted in the first resolved observations of a cometary nucleus in the FUV throughout much of its orbit. Upon arrival in 2014, initial characteristics and properties of the surface were derived for the northern hemisphere, revealing a dark, homogeneous, and blue-sloped surface in the FUV with an average geometric albedo of 5% at 1475 Å, consistent with a homogeneous layer of dust covering that hemisphere and similar to nucleus properties derived for this and other comets in the visible. Now, with a fully calibrated dataset, properties of the southern and northern hemispheres, before and after perihelion, have been quantified and preliminarily show minimal change in the comet's surface in the FUV through the apparition. Analyses are ongoing and we will highlight any detected variability. En-route to C-G, Alice made history during the flybys of asteroid (2867) Steins and (21) Lutetia obtaining the first global FUV reflectivity measurement and acquiring spatially resolved observations of an asteroid surface, respectively. The asteroid properties will be compared to those derived for C-G to demonstrate commonalities across small bodies

  5. DASTCOM5: A Portable and Current Database of Asteroid and Comet Orbit Solutions

    Science.gov (United States)

    Giorgini, Jon D.; Chamberlin, Alan B.

    2014-11-01

    A portable direct-access database containing all NASA/JPL asteroid and comet orbit solutions, with the software to access it, is available for download (ftp://ssd.jpl.nasa.gov/pub/xfr/dastcom5.zip; unzip -ao dastcom5.zip). DASTCOM5 contains the latest heliocentric IAU76/J2000 ecliptic osculating orbital elements for all known asteroids and comets as determined by a least-squares best-fit to ground-based optical, spacecraft, and radar astrometric measurements. Other physical, dynamical, and covariance parameters are included when known. A total of 142 parameters per object are supported within DASTCOM5. This information is suitable for initializing high-precision numerical integrations, assessing orbit geometry, computing trajectory uncertainties, visual magnitude, and summarizing physical characteristics of the body. The DASTCOM5 distribution is updated as often as hourly to include newly discovered objects or orbit solution updates. It includes an ASCII index of objects that supports look-ups based on name, current or past designation, SPK ID, MPC packed-designations, or record number. DASTCOM5 is the database used by the NASA/JPL Horizons ephemeris system. It is a subset exported from a larger MySQL-based relational Small-Body Database ("SBDB") maintained at JPL. The DASTCOM5 distribution is intended for programmers comfortable with UNIX/LINUX/MacOSX command-line usage who need to develop stand-alone applications. The goal of the implementation is to provide small, fast, portable, and flexibly programmatic access to JPL comet and asteroid orbit solutions. The supplied software library, examples, and application programs have been verified under gfortran, Lahey, Intel, and Sun 32/64-bit Linux/UNIX FORTRAN compilers. A command-line tool ("dxlook") is provided to enable database access from shell or script environments.

  6. Orbit Refinement of Asteroids and Comets Using a Robotic Telescope Network

    Science.gov (United States)

    Lantz Caughey, Austin; Brown, Johnny; Puckett, Andrew W.; Hoette, Vivian L.; Johnson, Michael; McCarty, Cameron B.; Whitmore, Kevin; UNC-Chapel Hill SKYNET Team

    2016-01-01

    We report on a multi-semester project to refine the orbits of asteroids and comets in our Solar System. One of the newest fields of research for undergraduate Astrophysics students at Columbus State University is that of asteroid astrometry. By measuring the positions of an asteroid in a set of images, we can reduce the overall uncertainty in the accepted orbital parameters of that object. These measurements, using our WestRock Observatory (WRO) and several other telescopes around the world, are being published through the Minor Planet Center (MPC) and benefit the global community.Three different methods are used to obtain these observations. First, we use our own 24-inch telescope at WRO, located in at CSU's Coca-Cola Space Science Center in downtown Columbus, Georgia . Second, we have access to data from the 20-inch telescope at Stone Edge Observatory in El Verano, California. Finally, we may request images remotely using Skynet, an online worldwide network of robotic telescopes. Our primary and long-time collaborator on Skynet has been the "41-inch" reflecting telescope at Yerkes Observatory in Williams Bay, Wisconsin. Thus far, we have used these various telescopes to refine the orbits of more than 15 asteroids and comets. We have also confirmed the resulting reduction in orbit-model uncertainties using Monte Carlo simulations and orbit visualizations, using Find_Orb and OrbitMaster software, respectively.Before any observatory site can be used for official orbit refinement projects, it must first become a trusted source of astrometry data for the MPC. We have therefore obtained Observatory Codes not only for our own WestRock Observatory (W22), but also for 3 Skynet telescopes that we may use in the future: Dark Sky Observatory in Boone, North Carolina (W38) Hume Observatory in Santa Rosa, California (U54) and Athabasca University Geophysical Observatory in Athabasca, Alberta, Canada (U96).

  7. Orbital motion in strongly perturbed environments applications to asteroid, comet and planetary satellite orbiters

    CERN Document Server

    Scheeres, Daniel J

    2012-01-01

    The proposed book will provide a detailed, technical introduction to the analysis of orbital motion in strongly perturbed environments, focusing on motion about small Solar System bodies, such as comets and asteroids. The author shows why such small bodies are of interest and why they can be used as a motivation for the general analysis of orbital mechanics. He shows how it is possible to model the small body environment, including specialised cases such as those of binary asteroids, comets and ‘rubble piles’, and how the fundamental equations of motion are derived. The properties of the various solutions to the equations of motion are described and the methods of analysis and their application are discussed. Both ballistic motion and powered motion on and about small bodies are considered and case studies for different small body missions are presented. The author concludes his comprehensive treatment with a discussion of the mechanics of multi-body small body systems and a review of advanced topics and ...

  8. Optical observations of the Phoenicid meteor shower in 2014 and activity of comet 289P/Blanpain in the early 20th century

    Science.gov (United States)

    Fujiwara, Yasunori; Nakamura, Takuji; Uehara, Satoshi; Sagayama, Toru; Toda, Hiroyuki

    2017-08-01

    Optical observations of the Phoenicid meteor shower were made in North Carolina, USA, with seven video cameras and two digital cameras over a period of about 5 hr between 22:30 UT on 2014 December 1 and 04:00 UT on December 2. Activity of the Phoenicids was confirmed during this period, including the predicted maximum around 00 h UT on December 2. The activity level was not high, considering that 29 Phoenicid meteors and 109 non-Phoenicid meteors were detected. A gentle peak in the activity was recognized between 01:00 UT and 03:00 UT on December 2. The compact radiant of the Phoenicids agreed well with what was predicted. A comparison of the observed and predicted peak times, radiant position, bright meteors' dominance, and radiants' spread revealed that the observed meteors originated from the dust trails formed by comet 289P/Blanpain at the perihelion passage in the early 20th century. This indicates that the parent body of the Phoenicids, comet 289P/Blanpain, was still active as a comet in the early 20th century and provided meteoroids, although its activity level was significantly weaker than that at the beginning of the 19th century.

  9. DIRBE Comet Trails

    Science.gov (United States)

    Arendt, Richard G.

    2015-01-01

    Re-examination of the COBE DIRBE data reveals the thermal emission of several comet dust trails.The dust trails of 1P/Halley, 169P/NEAT, and 3200 Phaethon have not been previously reported.The known trails of 2P/Encke, and 73P/Schwassmann-Wachmann 3 are also seen. The dust trails have 12 and 25 microns surface brightnesses of comet, but others are best seen at high ecliptic latitudes as the Earth passes over or under the dust trail. All these comets have known associations with meteor showers. This re-examination also reveals one additional comet and 13 additional asteroids that had not previously been recognized in the DIRBE data.

  10. IHW COMET HALLEY METEOR ETA AQUARID VISUAL DATA V1.0

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA's International Halley Watch (IHW) has created a Comet Halley Archive. The collection of data spans the full wavelength range as submitted by scientists to the...

  11. IHW COMET HALLEY METEOR ORIONID VISUAL DATA V1.0

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA's International Halley Watch (IHW) has created a Comet Halley Archive. The collection of data spans the full wavelength range as submitted by scientists to the...

  12. IHW COMET HALLEY METEOR ORIONID RADAR DATA V1.0

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA's International Halley Watch (IHW) has created a Comet Halley Archive. The collection of data spans the full wavelength range as submitted by scientists to the...

  13. IHW COMET HALLEY METEOR ETA AQUARID RADAR DATA V1.0

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA's International Halley Watch (IHW) has created a Comet Halley Archive. The collection of data spans the full wavelength range as submitted by scientists to the...

  14. Protection of the human race against natural hazards (asteroids, comets, volcanoes, earthquakes)

    Science.gov (United States)

    Smith, Joseph V.

    1985-10-01

    Although we justifiably worry about the danger of nuclear war to civilization, and perhaps even to survival of the human race, we tend to consider natural hazards (e.g., comets, asteroids, volcanoes, earthquakes) as unavoidable acts of God. In any human lifetime, a truly catastrophic natural event is very unlikely, but ultimately one will occur. For the first time in human history we have sufficient technical skills to begin protection of Earth from some natural hazards. We could decide collectively throughout the world to reassign resources: in particular, reduction of nuclear and conventional weapons to a less dangerous level would allow concomitant increase of international programs for detection and prevention of natural hazards. Worldwide cooperation to mitigate natural hazards might help psychologically to lead us away from the divisive bickering that triggers wars. Future generations could hail us as pioneers of peace and safety rather than curse us as agents of death and destruction.

  15. Collisional Histories of Comets and Trojan Asteroids: Diopside, Magnesite, and Fayalite Impact Studies

    Science.gov (United States)

    Lederer, Susan M.; Jensen, E. A.; Wooden, D. H.; Lindsay, S. S.; Nakamura-Messenger, K.; Smith, D. C.; Keller, L. P.; Cintala, M. J.; Zolensky, M. E.

    2012-10-01

    Comets and asteroids have weathered dynamic histories, as evidenced by their rough surfaces. The Nice model describes a violent reshuffling of small bodies during the Late Heavy Bombardment, with collisions acting to grind these planetesimals away. This creates an additional source of impact material that can re-work the surfaces of the larger bodies over the lifetime of the solar system. Here, we investigate the possibility that signatures due to impacts (e.g. from micrometeoroids or meteoroids) could be detected in their spectra, and how that can be explained by the physical manifestation of shock in the crystalline structure of minerals. All impact experiments were conducted in the Johnson Space Center Experimental Impact Laboratory using the vertical gun. Impact speeds ranged from 2.0 km/s to 2.8 km/s. All experiments were conducted at room temperature. Minerals found in comets and asteroids were chosen as targets, including diopside (MgCaSi2O6, monoclinic pyroxene), magnesite (MgCO3, carbonate), and fayalite (FeSiO4, olivine). Impacted samples were analyzed using a Fourier Transform Infrared Spectrometer (FTIR) and a Transmission Electron Microscope (TEM). Absorbance features in the 8-13 µm spectral region demonstrate relative amplitude changes as well as wavelength shifts. Corresponding TEM images exhibit planar shock dislocations in the crystalline structure, attributed to deformation at high strain and low temperatures. Elongating or shortening the axes of the crystalline structure of forsterite (Mg2SiO4, olivine) using a discrete dipole approximation model (Lindsay et al., submitted) yields changes in spectral features similar to those observed in our impacted laboratory minerals. Results on forsterite and orthoenstatite can be found in Jensen, et al., this meeting. Funding was provided by the NASA PG&G grant 09-PGG09-0115, NSF grant AST-1010012, and a Cottrell College Scholarship through the Research Corporation.

  16. Numerical and probabilistic analysis of asteroid and comet impact hazard mitigation

    Energy Technology Data Exchange (ETDEWEB)

    Plesko, Catherine S [Los Alamos National Laboratory; Weaver, Robert P [Los Alamos National Laboratory; Huebner, Walter F [Los Alamos National Laboratory

    2010-09-09

    The possibility of asteroid and comet impacts on Earth has received significant recent media and scientific attention. Still, there are many outstanding questions about the correct response once a potentially hazardous object (PHO) is found. Nuclear munitions are often suggested as a deflection mechanism because they have a high internal energy per unit launch mass. However, major uncertainties remain about the use of nuclear munitions for hazard mitigation. There are large uncertainties in a PHO's physical response to a strong deflection or dispersion impulse like that delivered by nuclear munitions. Objects smaller than 100 m may be solid, and objects at all sizes may be 'rubble piles' with large porosities and little strength. Objects with these different properties would respond very differently, so the effects of object properties must be accounted for. Recent ground-based observations and missions to asteroids and comets have improved the planetary science community's understanding of these objects. Computational power and simulation capabilities have improved such that it is possible to numerically model the hazard mitigation problem from first principles. Before we know that explosive yield Y at height h or depth -h from the target surface will produce a momentum change in or dispersion of a PHO, we must quantify energy deposition into the system of particles that make up the PHO. Here we present the initial results of a parameter study in which we model the efficiency of energy deposition from a stand-off nuclear burst onto targets made of PHO constituent materials.

  17. Collisional Histories of Comets and Trojan Asteroids: Diopside, Magnesite, and Fayalite Impact Studies

    Science.gov (United States)

    Lederer, S. M.; Jensen, E. A.; Wooden, D. H.; Lindsay, S. S.; Nakamura-Messenger, K.; Smith, D. C.; Keller, L. P.; Cintala, M. J.; Zolensky, M. E.

    2012-01-01

    Comets and asteroids have weathered dynamic histories, as evidenced by their rough surfaces. The Nice model describes a violent reshuffling of small bodies during the Late Heavy Bombardment, with collisions acting to grind these planetesimals away. This creates an additional source of impact material that can re-work the surfaces of the larger bodies over the lifetime of the solar system. Here, we investigate the possibility that signatures due to impacts (e.g. from micrometeoroids or meteoroids) could be detected in their spectra, and how that can be explained by the physical manifestation of shock in the crystalline structure of minerals. All impact experiments were conducted in the Johnson Space Center Experimental Impact Laboratory using the vertical gun. Impact speeds ranged from approx.2.0 km/s to approx.2.8 km/s. All experiments were conducted at room temperature. Minerals found in comets and asteroids were chosen as targets, including diopside (MgCaSi2O6, monoclinic pyroxene), magnesite (MgCO3, carbonate), and fayalite (FeSiO4, olivine). Impacted samples were analyzed using a Fourier Transform Infrared Spectrometer (FTIR) and a Transmission Electron Microscope (TEM). Absorbance features in the 8-13 m spectral region demonstrate relative amplitude changes as well as wavelength shifts. Corresponding TEM images exhibit planar shock dislocations in the crystalline structure, attributed to deformation at high strain and low temperatures. Elongating or shortening the axes of the crystalline structure of forsterite (Mg2SiO4, olivine) using a discrete dipole approximation model (Lindsay et al., submitted) yields changes in spectral features similar to those observed in our impacted laboratory minerals.

  18. Hartley and Itokawa: small comet and asteroid with similar morphologies and structures

    Science.gov (United States)

    Kochemasov, G. G.

    2011-10-01

    at the convex bulge, from the antipodean side (Fig. 5). The smaller rocky asteroid Itokawa (0.5 km long, Fig. 2) is surprisingly similar in shape and structure to the icy core of Hart ley. It is also bent and rich in cross-cutting lineations o 4 direct ions marked by small holes-craters. But here they are ext inct and lack of gas -dust jets. One sees a transition from a volat ile rich comet core to an ext inct mostly rocky mass - asteroid. In both cases (comet core and as teroid) in the middle develops a smooth "wais t". The bulged convex and antipodal concave segments -hemispheres in rotating bodies require somewhat different densities of composing them masses to equilibrate angular momentum of two halves (compare with the Ea rth's hemis pheres : the eas tern continental "granitic" and wes tern Pacific "bas altic"). The near-IR images of two asteroids (Fig.6-7) confirm this. The concave and convex s ides are co mpos itionally d ifferent. In the Eros ' cas e the concave s ide is rich er in pyroxene, thus denser.

  19. Collisional Effects on Magnesium-rich Minerals found in Comets and Asteroids

    Science.gov (United States)

    Lederer, S.; Jensen, E.; Strojia, C.; Smith, D.; Keller, L.; Berger, E.; Lindsay, S.; Wooden, D.; Cintala, M.; Zolensky, M.

    2014-01-01

    While generally touted to be the least-altered bodies remaining from the age of the solar system's formation, comets and asteroids have undergone evolutionary processing throughout the 4.5-billion-year lifetime of the solar system. They have suffered the effects of collisions by impactors ranging in size from micrometeoroids to other comets and asteroids. As such, we must ask ourselves: can we detect these evolutionary effects remotely through telescopic observations? With this in mind, a suite of experiments were conducted, impacting magnesium-rich minerals as analogues to those that have been detected in the spectra of both asteroid surfaces and in the dust of cometary comae, including forsterite (Mg2SiO4, olivine), orthoenstatite (Mg2SiO3, pyroxene), diopside (MgCaSi2O6, monoclinic pyroxene), and magnesite (MgCO3, carbonate). These minerals were impacted at velocities ranging from 2.0 km/s to 2.8 km/s using the vertical gun in the Experimental Impact Laboratory (EIL) at NASA Johnson Space Center. These speeds mimic typical velocities of impacts occurring in the Kuiper belt [1]. Two classes of projectile were used: spherical alumina ceramic, whose density mimics that of rock, and cylinders made from the same material that they impacted (e.g., forsterite impactors for forsterite targets, etc.). The peak shock pressure varies significantly, depending on the target and impactor materials and the velocity; thus, shock effects differed in targets impacted at the same velocity but with compositionally different projectiles. The results indicate both: (a) how varying the impactor-density might change the outcome from a scientific viewpoint, as well as (b) possible contamination effects of the ceramic projectile in the resultant spectra of the target minerals from an experimental perspective. Temperature effects were also investigated by impacting samples at both 25 deg. and -25 deg. to: (a) probe whether the varying temperatures experienced by small bodies plays a role

  20. Impact hazard mitigation: understanding the effects of nuclear explosive outputs on comets and asteroids

    Energy Technology Data Exchange (ETDEWEB)

    Clement, Ralph R C [Los Alamos National Laboratory; Plesko, Catherine S [Los Alamos National Laboratory; Bradley, Paul A [Los Alamos National Laboratory; Conlon, Leann M [Los Alamos National Laboratory

    2009-01-01

    The NASA 2007 white paper ''Near-Earth Object Survey and Deflection Analysis of Alternatives'' affirms deflection as the safest and most effective means of potentially hazardous object (PHO) impact prevention. It also calls for further studies of object deflection. In principle, deflection of a PHO may be accomplished by using kinetic impactors, chemical explosives, gravity tractors, solar sails, or nuclear munitions. Of the sudden impulse options, nuclear munitions are by far the most efficient in terms of yield-per-unit-mass launched and are technically mature. However, there are still significant questions about the response of a comet or asteroid to a nuclear burst. Recent and ongoing observational and experimental work is revolutionizing our understanding of the physical and chemical properties of these bodies (e.g ., Ryan (2000) Fujiwara et al. (2006), and Jedicke et al. (2006)). The combination of this improved understanding of small solar-system bodies combined with current state-of-the-art modeling and simulation capabilities, which have also improved dramatically in recent years, allow for a science-based, comprehensive study of PHO mitigation techniques. Here we present an examination of the effects of radiation from a nuclear explosion on potentially hazardous asteroids and comets through Monte Carlo N-Particle code (MCNP) simulation techniques. MCNP is a general-purpose particle transport code commonly used to model neutron, photon, and electron transport for medical physics reactor design and safety, accelerator target and detector design, and a variety of other applications including modeling the propagation of epithermal neutrons through the Martian regolith (Prettyman 2002). It is a massively parallel code that can conduct simulations in 1-3 dimensions, complicated geometries, and with extremely powerful variance reduction techniques. It uses current nuclear cross section data, where available, and fills in the gaps with

  1. Don Quixote --- a possible parent body of a meteor shower

    Science.gov (United States)

    Rudawska, R.; Vaubaillon, J.

    2014-07-01

    This talk addresses the topic of meteoroid stream parent body in relation to meteor showers observed on the Earth. We carry out a further search to investigate the possibility of meteor shower observations caused by particles ejected from (3552) Don Quixote. The (3552) Don Quixote asteroid was discovered in 1983 as an Amor asteroid. The Tisserand parameter for the orbit has a value of 2.315 with respect to Jupiter, which indicates a comet-like orbit. The diameter of the object calculated from the absolute magnitude, is in the range of 12.3--24.5 km. It all makes Don Quixote a good candidate for a short-period comet among known near-Earth objects, which the recently observed cometary activity confirms [1]. We have investigated the orbital evolution of the meteoroid stream originated from Don Quixote. If the object was active in the past, it might be a parent body for a meteor shower observed on the Earth. The model for the generation and evolution of the meteoroid stream in the Solar System is taken from [2]. The asteroid's orbital elements and physical properties are taken from the JPL horizons website. The ejections of meteoroids from the asteroid surface took place when the asteroid was passing its perihelion between 5000 B.C. and 2013 A.D. Next, the orbits of ejected meteoroids were integrated to the year 2050. If a meteoroid is sufficiently close to the Earth, its orbital parameters are saved and compared with known showers.

  2. Planning ahead for asteroid and comet hazard mitigation, phase 1: parameter space exploration and scenario modeling

    Energy Technology Data Exchange (ETDEWEB)

    Plesko, Catherine S [Los Alamos National Laboratory; Clement, R Ryan [Los Alamos National Laboratory; Weaver, Robert P [Los Alamos National Laboratory; Bradley, Paul A [Los Alamos National Laboratory; Huebner, Walter F [Los Alamos National Laboratory

    2009-01-01

    The mitigation of impact hazards resulting from Earth-approaching asteroids and comets has received much attention in the popular press. However, many questions remain about the near-term and long-term, feasibility and appropriate application of all proposed methods. Recent and ongoing ground- and space-based observations of small solar-system body composition and dynamics have revolutionized our understanding of these bodies (e.g., Ryan (2000), Fujiwara et al. (2006), and Jedicke et al. (2006)). Ongoing increases in computing power and algorithm sophistication make it possible to calculate the response of these inhomogeneous objects to proposed mitigation techniques. Here we present the first phase of a comprehensive hazard mitigation planning effort undertaken by Southwest Research Institute and Los Alamos National Laboratory. We begin by reviewing the parameter space of the object's physical and chemical composition and trajectory. We then use the radiation hydrocode RAGE (Gittings et al. 2008), Monte Carlo N-Particle (MCNP) radiation transport (see Clement et al., this conference), and N-body dynamics codes to explore the effects these variations in object properties have on the coupling of energy into the object from a variety of mitigation techniques, including deflection and disruption by nuclear and conventional munitions, and a kinetic impactor.

  3. FAST RADIO BURSTS: COLLISIONS BETWEEN NEUTRON STARS AND ASTEROIDS/COMETS

    Energy Technology Data Exchange (ETDEWEB)

    Geng, J. J.; Huang, Y. F., E-mail: hyf@nju.edu.cn [School of Astronomy and Space Science, Nanjing University, Nanjing 210046 (China)

    2015-08-10

    Fast radio bursts (FRBs) are newly discovered radio transient sources. Their high dispersion measures indicate an extragalactic origin. However, due to the lack of observational data in other wavelengths, their progenitors still remain unclear. Here we suggest that the collisions between neutron stars (NSs) and asteroids/comets are promising mechanisms for FRBs. During the impact process, a hot plasma fireball forms after the material of the small body penetrates into the NS surface. The ionized matter inside the fireball then expands along the magnetic field lines. Coherent radiation from the thin shell at the top of the fireball will account for the observed FRBs. Our scenario can reasonably explain the main features of FRBs, such as their durations, luminosities, and the event rate. We argue that for a single NS, FRBs are not likely to happen repeatedly in a forseeable timespan since such impacts are of low probability. We predict that faint remnant X-ray emissions should be associated with FRBs, but it may be too faint to be detected by detectors at work.

  4. DUST FROM COMET 209P/LINEAR DURING ITS 2014 RETURN: PARENT BODY OF A NEW METEOR SHOWER, THE MAY CAMELOPARDALIDS

    Energy Technology Data Exchange (ETDEWEB)

    Ishiguro, Masateru [Department of Physics and Astronomy, Seoul National University, Gwanak, Seoul 151-742 (Korea, Republic of); Kuroda, Daisuke [Okayama Astrophysical Observatory, National Astronomical Observatory of Japan, Asakuchi, Okayama 719-0232 (Japan); Hanayama, Hidekazu [Ishigakijima Astronomical Observatory, National Astronomical Observatory of Japan, Ishigaki, Okinawa 907-0024 (Japan); Takahashi, Jun; Takagi, Yuhei; Morihana, Kumiko; Honda, Satoshi; Arai, Akira [Nishi-Harima Astronomical Observatory, Center for Astronomy, University of Hyogo, Sayo, Hyogo 679-5313 (Japan); Hasegawa, Sunao; Sarugaku, Yuki [Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Sagamihara, Kanagawa 252-5210 (Japan); Watanabe, Makoto; Imai, Masataka; Goda, Shuhei [Department of Cosmosciences, Graduate School of Science, Hokkaido University, Sapporo 060-0810 (Japan); Akitaya, Hiroshi [Hiroshima Astrophysical Science Center, Hiroshima University, Higashihiroshima, Hiroshima 739-8526 (Japan); Sekiguchi, Kazuhiro [National Astronomical Observatory of Japan, National Institute of Natural Sciences, Mitaka, Tokyo 181-8588 (Japan); Oasa, Yumiko [Faculty of Education, Saitama University, Sakura, Saitama 338-8570 (Japan); Saito, Yoshihiko [Department of Physics, Tokyo Institute of Technology, Meguro-ku, Tokyo 152-8551 (Japan); Morokuma, Tomoki [Institute of Astronomy, Graduate School of Science, The University of Tokyo, Mitaka, Tokyo 181-0015 (Japan); Murata, Katsuhiro [Department of Astrophysics, Nagoya University, Chikusa-ku, Nagoya 464-8602 (Japan); Nogami, Daisaku [Department of Astronomy, Graduate School of Science, Kyoto University, Kyoto 606-8502 (Japan); and others

    2015-01-10

    We report a new observation of the Jupiter family comet 209P/LINEAR during its 2014 return. The comet is recognized as a dust source of a new meteor shower, the May Camelopardalids. 209P/LINEAR was apparently inactive at a heliocentric distance r{sub h} = 1.6 AU and showed weak activity at r{sub h} ≤ 1.4 AU. We found an active region of <0.001% of the entire nuclear surface during the comet's dormant phase. An edge-on image suggests that particles up to 1 cm in size (with an uncertainty of factor 3-5) were ejected following a differential power-law size distribution with index q = –3.25 ± 0.10. We derived a mass-loss rate of 2-10 kg s{sup –1} during the active phase and a total mass of ≈5 × 10{sup 7} kg during the 2014 return. The ejection terminal velocity of millimeter- to centimeter-sized particles was 1-4 m s{sup –1}, which is comparable to the escape velocity from the nucleus (1.4 m s{sup –1}). These results imply that such large meteoric particles marginally escaped from the highly dormant comet nucleus via the gas drag force only within a few months of the perihelion passage.

  5. Comets Captured in the Main Asteroid Belt: Evidence for a Lost Neptune-Like Planet

    Science.gov (United States)

    Bottke, W. F., Jr.

    2016-12-01

    The Nice model describes a family of solutions where the giant planets started in a different configuration, experienced a dynamical instability, and reached their final configuration via interactions with a sea of leftover comet-like planetesimals. The most successful version of this model assumes there were five planets between 5-20 AU: Jupiter, Saturn, Uranus, Neptune, and a Neptune-like body. The extra Neptune-like body was ejected via a Jupiter encounter but not before it helped populate stable niches with disk planetesimals across the Solar System (e.g., Trojans, irregular satellites). Here we use numerical simulations to show that the Neptune-like body directly interacted with the main belt for several tens of thousands of years, enough to help capture numerous disk planetesimals into the asteroid belt and the first-order mean motion resonances with Jupiter. We find our model runs produce the right proportion of large P- and D-type asteroids in the inner, central, and outer main belt, while also populating the Hilda and Thule populations in Jupiter's 3/2 and 4/3 resonances. For example, in the central main belt between 2.5-2.8 AU, we predict the largest P/D types should be 180 ± 25 km, compared to the D 177 km diameter P-type (409) Aspasia, while there should be 20 (+20, -10) D > 150 km bodies, compared to 17 known such bodies. Our model does produce a factor of a few overabundance of D > 10 km P/D-types in the main belt, though this mismatch is likely explained by removal mechanisms not yet explored (e.g., thermal destruction of D > 10 km disk planetesimals en route to the inner solar system, collision evolution in the main belt over 4 Gyr, dynamical losses in the main belt via Yarkovsky thermal forces over 4 Gyr). Overall, our five-planet instability model not only reproduces the major trends identified by Levison et al. (2009), but it also provides a more satisfying match to constraints. Accordingly, it provides us with strong supporting evidence that

  6. Comets

    International Nuclear Information System (INIS)

    Hughes, D.W.

    1982-01-01

    Comets are objects of considerable fascination and this paper reviews the present knowledge of the physical structure of the cometary nucleus, coma and tail, the orbits of comets in the Solar System, the proposed mechanisms of cometary origin, the decay processes suffered by comets, and the ways in which they can be observed from Earth and by spacecraft. (author)

  7. Small Bodies, Big Concepts: Engaging Teachers and Their Students in Visual Analysis of Comets and Asteroids

    Science.gov (United States)

    Cobb, W. H.; Buxner, S.; Lebofsky, L. A.; Ristvey, J.; Weeks, S.; Zolensky, M.

    2011-12-01

    Small Bodies, Big Concepts is a multi-disciplinary, professional development project that engages 5th - 8th grade teachers in high end planetary science using a research-based pedagogical framework, Designing Effective Science Instruction (DESI). In addition to developing sound background knowledge with a focus on visual analysis, teachers' awareness of the process of learning new content is heightened, and they use that experience to deepen their science teaching practice. Culling from NASA E/PO educational materials, activities are sequenced to enhance conceptual understanding of big ideas in space science: what do we know, how do we know it, why do we care? Helping teachers develop a picture of the history and evolution of our understanding of the solar system, and honing in on the place of comets and asteroids in helping us answer old questions and discover new ones, teachers see the power and excitement underlying planetary science as human endeavor. Research indicates that science inquiry is powerful in the classroom and mission scientists are real-life models of science inquiry in action. Using guest scientist facilitators from the Planetary Science Institute, NASA Johnson Space Center, Lockheed Martin, and NASA E/PO professionals from McREL and NASA AESP, teachers practice framing scientific questions, using current visual data, and adapting NASA E/PO activities related to current exploration of asteroids and comets in our Solar System. Cross-curricular elements included examining research-based strategies for enhancing English language learners' ability to engage in higher order questions and a professional astronomy artist's insight into how visual analysis requires not just our eyes engaged, but our brains: comparing, synthesizing, questioning, evaluating, and wondering. This summer we pilot tested the SBBC curriculum with thirteen 5th- 10th grade teachers modeling a variety of instructional approaches over eight days. Each teacher developed lesson plans

  8. Don Quixote-A possible parent body of a meteor shower

    Science.gov (United States)

    Rudawska, Regina; Vaubaillon, Jeremie

    2015-12-01

    Asteroid 3552 Don Quixote (1983 SA) orbits the Sun on an orbit that resembles that of a short-period comet. This, together with its recently observed cometary activity, makes it a good candidate for a parent body of a meteor shower. Model calculations show that the particles originated from Don Quixote pass close enough to Earth orbit to search for a meteor shower activity. Corresponding meteor showers were found in CAMS (Rudawska and Jenniskens, 2014) and EDMOND (Kornoš et al., 2014) video observations. The κ Lyrids and August μ Draconids (IAU#464 and IAU#470, respectively), a similarly inclined stream active in the summer, are associated with 3552 Don Quixote.

  9. Reconstructing the orbit of the Chelyabinsk meteor using satellite observations

    DEFF Research Database (Denmark)

    Proud, Simon Richard

    2013-01-01

    The large number of objects in a range of orbits around the Sun means that some will inevitably intersect the Earth, becoming a meteor. These objects are commonly comet fragments or asteroids. To determine the type of a particular meteor requires knowledge of its trajectory and orbital path...... that is typically estimated by using ground-based observations such as images or radar measurements. A lack of data can, however, make this difficult and create large uncertainties in the reconstructed orbit. Here I show a new method for estimating a meteor's trajectory, and hence allowing computation of the orbit......, based upon measurements from satellite sensors. The meteor that fell on 15 February 2013 is used as an example and the resulting orbit is in broad agreement with estimates from other observations. This new technique represents an alternative method for trajectory determination that may be particularly...

  10. A mathematical model of the passage of an asteroid-comet body through the Earth’s atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Shaydurov, V., E-mail: shaidurov04@mail.ru [Institute of Computational Modeling of SB RAS, 660036 Akademgorodok, Krasnoyarsk (Russian Federation); Siberian Federal University, 79 Svobodny pr., 660041 Krasnoyarsk (Russian Federation); Shchepanovskaya, G.; Yakubovich, M. [Institute of Computational Modeling of SB RAS, 660036 Akademgorodok, Krasnoyarsk (Russian Federation)

    2015-10-28

    In the paper, a mathematical model and a numerical algorithm are proposed for modeling the complex of phenomena which accompany the passage of a friable asteroid-comet body through the Earth’s atmosphere: the material ablation, the dissociation of molecules, and the radiation. The proposed model is constructed on the basis of the Navier-Stokes equations for viscous heat-conducting gas with an additional equation for the motion and propagation of a friable lumpy-dust material in air. The energy equation is modified for the relation between two its kinds: the usual energy of the translation of molecules (which defines the temperature and pressure) and the combined energy of their rotation, oscillation, electronic excitation, dissociation, and radiation. For the mathematical model of atmosphere, the distribution of density, pressure, and temperature in height is taken as for the standard atmosphere. An asteroid-comet body is taken initially as a round body consisting of a friable lumpy-dust material with corresponding density and significant viscosity which far exceed those for the atmosphere gas. A numerical algorithm is proposed for solving the initial-boundary problem for the extended system of Navier-Stokes equations. The algorithm is the combination of the semi-Lagrangian approximation for Lagrange transport derivatives and the conforming finite element method for other terms. The implementation of these approaches is illustrated by a numerical example.

  11. Touchless Despinning of Asteroids and Comets via Neutral Beam Emitting Spacecraft

    Data.gov (United States)

    National Aeronautics and Space Administration — This project seeks to design, build, and test a device that is capable of despinning an asteroid without the need for affixing the spacecraft to the surface. This...

  12. Asteroids IV

    Science.gov (United States)

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

    . Asteroids, like planets, are driven by a great variety of both dynamical and physical mechanisms. In fact, images sent back by space missions show a collection of small worlds whose characteristics seem designed to overthrow our preconceived notions. Given their wide range of sizes and surface compositions, it is clear that many formed in very different places and at different times within the solar nebula. These characteristics make them an exciting challenge for researchers who crave complex problems. The return of samples from these bodies may ultimately be needed to provide us with solutions. In the book Asteroids IV, the editors and authors have taken major strides in the long journey toward a much deeper understanding of our fascinating planetary ancestors. This book reviews major advances in 43 chapters that have been written and reviewed by a team of more than 200 international authorities in asteroids. It is aimed to be as comprehensive as possible while also remaining accessible to students and researchers who are interested in learning about these small but nonetheless important worlds. We hope this volume will serve as a leading reference on the topic of asteroids for the decade to come. We are deeply indebted to the many authors and referees for their tremendous efforts in helping us create Asteroids IV. We also thank the members of the Asteroids IV scientific organizing committee for helping us shape the structure and content of the book. The conference associated with the book, "Asteroids Comets Meteors 2014" held June 30-July 4, 2014, in Helsinki, Finland, did an outstanding job of demonstrating how much progress we have made in the field over the last decade. We are extremely grateful to our host Karri Muinonnen and his team. The editors are also grateful to the Asteroids IV production staff, namely Renée Dotson and her colleagues at the Lunar and Planetary Institute, for their efforts, their invaluable assistance, and their enthusiasm; they made life as

  13. Religous History can be used to Study Aspects of Comets, Asteroids, Meteroids

    Science.gov (United States)

    Struck, J.-T.

    2012-05-01

    Meteors can be studied with religious history. St. Laurence is tied to Perseids as the shower occurs around 8/10 Laurence's Day. Shooting stars were called "Fiery tears of St. Laurence." Moms of Saint Dominic,Thomas Aquinas both saw stars in visions.

  14. 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.

  15. Amino Acids in Asteroids and Comets: Implications for the Origin of Life on Earth and Possibly Elsewhere

    Science.gov (United States)

    Glavin, Daniel

    2012-01-01

    Meteorites provide a record of the chemical processes that occurred in the early solar system before life began on Earth. The delivery of organic matter by asteroids, comets, and their fragments to the Earth and other planetary bodies in our solar system could have been an important source of the prebiotic organic inventory needed for the emergence of life. Amino acids are essential components of proteins and enzymes in life on Earth and these prebiotic organic compounds have been detected in a wide variety of carbon-rich meteorites, the majority of which have been determined to be extraterrestrial in origin. In addition, many amino acids are structurally chiral (they possess handedness) and with a few very rare exceptions, only left handed (L) amino acids are found in biology, while all known abiotic syntheses of amino acids result in equal mixtures of left and right handed (LD) amino acids. The discovery of a significant left handed amino acid imbalance of up to 20% in several different carbonaceous meteorites, could point toward a possible prebiotic contribution to the origin of biological homochirality by the exogenous delivery of extraterrestrial organic material to the early Earth. In this talk, I will focus on recent state-of-the-art measurements of the distribution, chirality, and isotopic composition of amino acids in meteorites and cometary samples carried out at the Goddard Astrobiology Analytical Laboratory. Results from the analyses of a variety of Antarctic meteorites, samples from comet Wild 2 returned by the STARDUST mission, and meteorite fragments of asteroid 2008 TC3 called Almahata Sitta recovered from northern Sudan will be discussed

  16. Dynamics of meteor streams

    International Nuclear Information System (INIS)

    Babadjanov, P.B.; Obrubov, YU.U.

    1987-01-01

    The overwhelming majority of meteor streams are generally assumed to be formed due to the decay of comets. The most effective process of the release of solid particles from a cometary nucleus is their ejection by sublimating gases when the comet approaches the Sun. The results of investigation of the Geminids and Quadrantids meteor stream evolution show that under the influence of planetary perturbations, the stream may originally be flat but then thicken depending on the variation range of orbital inclinations. Eventually, due to planetary perturbations, a meteor stream may take such a shape as to cause the start of several active showers at different solar longitudes

  17. DRBE comet trails

    Energy Technology Data Exchange (ETDEWEB)

    Arendt, Richard G., E-mail: Richard.G.Arendt@nasa.gov [CREST/UMBC, Code 665, NASA/GSFC, Greenbelt, MD 20771 (United States)

    2014-12-01

    Re-examination of the Cosmic Background Explorer Diffuse Infrared Background Experiment (DIRBE) data reveals the thermal emission of several comet dust trails. The dust trails of 1P/Halley, 169P/NEAT, and 3200 Phaethon have not been previously reported. The known trails of 2P/Encke and 73P/Schwassmann–Wachmann 3 are also seen. The dust trails have 12 and 25 μm surface brightnesses of <0.1 and <0.15 MJy sr{sup −1}, respectively, which is <1% of the zodiacal light intensity. The trails are very difficult to see in any single daily image of the sky, but are evident as rapidly moving linear features in movies of the DIRBE data. Some trails are clearest when crossing through the orbital plane of the parent comet, but others are best seen at high ecliptic latitudes as the Earth passes over or under the dust trail. All these comets have known associations with meteor showers. This re-examination also reveals 1 additional comet and 13 additional asteroids that had not previously been recognized in the DIRBE data.

  18. In Situ Measurements of Meteoric Ions

    Science.gov (United States)

    Grebowsky, Joseph M.; Aiken, Arthur C.; Einaudi, Franco (Technical Monitor)

    2001-01-01

    Extraterrestrial material is the source of metal ions in the Earth's atmosphere, Each year approx. 10(exp 8) kg of material is intercepted by the Earth. The origin of this material is predominantly solar orbiting interplanetary debris from comets or asteroids that crosses the Earth's orbit. It contains a very small amount of interstellar material. On occasion the Earth passes through enhanced amounts of debris associated with the orbit of a decaying comet. This leads to enhanced meteor shower displays for up to several days. The number flux of shower material is typically several times the average sporadic background influx of material. Meteoric material is some of the earliest material formed in the solar system. By studying the relative elemental abundances of atmospheric metal ions, information can be gained on the chemical composition of cometary debris and the chemical makeup of the early solar system. Using in situ sampling with rocket-borne ion mass spectrometers; there have been approximately 50 flights that made measurements of the metal ion abundances at attitudes between 80 and 130 km. It is this altitude range where incoming meteoric particles am ablated, the larger ones giving rise to visible meteor. displays. In several rocket measurements isotopic ratios of different atomic ion mass components and metal molecular ion concentrations have been determined and used to identify unambiguously the measured species and to investigate the processes controlling the metal ion distributions The composition of the Earth's ionosphere was first sampled by an ion mass spectrometer flown an a rocket in 1956. In 1958 a rocket-borne ion spectrometer identified, fbr the first time, a layer of metal ions near 95 km. These data were interpreted as evidence of an extraterrestrial rather than a terrestrial source. Istomin predicted: "It seems probable that with some improvement in the method that analysis of the ion composition in the E-region may be used for determining

  19. Deposition of steeply infalling debris - pebbles, boulders, snowballs, asteroids, comets - around stars

    Science.gov (United States)

    Brown, J. C.; Veras, D.; Gänsicke, B. T.

    2017-09-01

    When Comet Lovejoy plunged into the Sun, and survived, questions arose about the physics of infall of small bodies. [1,2] has already described this infall in detail. However, a more general analysis for any type of star has been missing. [3] generalized previous studies, with specific applications to white dwarfs. High-metallicity pollution is common in white dwarf stars hosting remnant planetary systems. However, they rarely have detectable debris accretion discs, possibly because much of the influx is fast steeply infalling debris in star-grazing orbits, producing a more tenuous signature than a slowly accreting disc. Processes governing such deposition between the Roche radius and photosphere have so far received little attention and we model them here analytically by extending recent work on sun-grazing comets to white dwarf systems. We find that the evolution of cm-to-km size infallers most strongly depends on two combinations of parameters, which effectively measure sublimation rate and binding strength. We then provide an algorithm to determine the fate of infallers for any white dwarf, and apply the algorithm to four limiting combinations of hot versus cool (young/old) white dwarfs with snowy (weak, volatile) versus rocky (strong, refractory) infallers. We find: (i) Total sublimation above the photosphere befalls all small infallers across the entire white dwarf temperature range, the threshold size rising with it and 100× larger for rock than snow. (ii) All very large objects fragment tidally regardless of temperature: for rock, a0 ≽ 105 cm; for snow, a0 ≽ 103 - 3 × 104 cm across all white dwarf cooling ages. (iii) A considerable range of infaller sizes avoids fragmentation and total sublimation, yielding impacts or grazes with cold white dwarfs. This range rapidly narrows with increasing temperature, especially for snowy bodies. Finally, we briefly discuss how the various forms of deposited debris may finally reach the photosphere surface itself.

  20. Laboratory Studies of Fischer-Tropsch-Type Reactions and Their Implications for Organics in Asteroids and Comets

    Science.gov (United States)

    Nuth, Joseph

    2011-01-01

    We have been studying Fischer-Tropsch type (FTT) reactions as a source for organic materials both in the gas phase of the solar nebula and incorporated into primitive comets and asteroids for almost 10 years, and over this time our concept has evolved greatly from the standard "catalytic" model to a much more robust chemical scenario. Our simulations have been conducted at temperatures that are much higher than we like, primarily for practical reasons such as the timescale of individual reactions, and we are just starting a series of measurements to allow us to measure reaction rates at temperatures from 873K down to as low as 373K. We have preliminary data on the carbon (d13C = -50) & nitrogen (d15N = +9.5) isotopic fractionation at 873K, but not on materials produced at lower temperature. Isotope values are on the VPDB scale for carbon and vs. Air for nitrogen. We have also investigated the noble gas trapping efficiency of the FTT process by adding a small amount of a noble gas mix to our standard synthesis mix. The noble gas ratio is 49:49:1:1::Ne:Ar:Kr:Xe. Xe and Kr are trapped at 873K and are more efficiently trapped at 673K with no isotopic fractionation at either temperature. Ar trapping is detected at 673K, but not at 873K. Ne has not yet been observed in our samples. The solar nebula was an extremely complex system, mixing materials from the innermost regions out to well into the zones where comets formed and thus mixing highly processed nebular materials with grains and coatings formed before the nebula began to collapse. Laboratory studies may provide the means to separate such diverse components based on carbon or nitrogen isotopic fractionation or the quantities of noble gases trapped in grain coatings and their thermal release patterns, among other observables. The ultimate goal of laboratory synthesis of nebular analogs is to provide the means to identifY the conditions under which natural samples were formed and the signatures of subsequent

  1. Meteors, meteorites and cosmic dust

    International Nuclear Information System (INIS)

    Lebedinets, V.N.

    1987-01-01

    The problem of meteorite origin and meteorite composition is discussed. Nowadays, most scientists suppose that the giant Oort cloud consisting of ice comet nuclei is the sourse of the meteor matter. A principle unity of the matter of meteorites falling to the Earth and cosmic dust is noted as well as that of meteorite bodies evaporating in the atmosphere and bearing meteors and bodies

  2. The meteoric night-glow

    International Nuclear Information System (INIS)

    Baggaley, W.J.

    1977-01-01

    There exist well-documented accounts of the observations of enhanced night-glow associated with spectacular meteor shower displays. Possible mechanisms responsible for this elusive phenomenon are examined. It is shown that the observed emission is not a direct consequence of the influx of meteors on the Earth but rather has its source in scattering of solar radiation by interplanetary micrometeoroids which form the dense dustclouds ejected by the parent comets of the associated meteor streams. (author)

  3. Meteor Beliefs Project: Meteors in the Maori astronomical traditions of New Zealand

    Science.gov (United States)

    Britton, Tui R.; Hamacher, Duane W.

    2014-02-01

    We review the literature for perceptions of meteors in the Maori culture of Aotearoa or New Zealand. We examine representations of meteors in religion, story, and ceremony. We find that meteors are sometimes personified as gods or children, or are seen as omens of death and destruction. The stories we found highlight the broad perception of meteors found throughout the Maori culture, and note that some early scholars conflated the terms comet and meteor.

  4. The Manson impact crater: Estimation of the energy of formation, possible size of the impacting asteroid or comet, and ejecta volume and mass

    Science.gov (United States)

    Roddy, D. J.; Shoemaker, E. M.; Anderson, R. R.

    1993-01-01

    A research program on the Manson impact structure has substantially improved our knowledge of the detailed features of this eroded crater. As part of our structural studies, we have derived a value of 21 km for the diameter of the final transient cavity formed during crater excavation. With this information, we can estimate the energy of formation of the Manson crater and the possible size of the impacting asteroid or comet. In addition, we have estimated the near- and far-field ejecta volumes and masses.

  5. Great Comets

    Science.gov (United States)

    Burnham, Robert

    2000-05-01

    Spectacular and mysterious objects that come and go in the night sky, comets have dwelt in our popular culture for untold ages. As remnants from the formation of the Solar system, they are objects of key scientific research and space missions. As one of nature's most potent and dramatic dangers, they pose a threat to our safety--and yet they were the origin of our oceans and perhaps even life itself. This beautifully illustrated book tells the story of the biggest and most awe-inspiring of all comets: those that have earned the title "Great." Robert Burnham focuses on the Great comets Hyakutake in 1996 and Hale-Bopp in 1997, which gripped attention worldwide because, for many, they were the first comets ever seen. He places these two recent comets in the context of their predecessors from past ages, among them the famous Comet Halley. Great Comets explains the exciting new discoveries that have come from these magnificent objects and profiles the spaceprobes to comets due for launch in the next few years. The book even takes a peek behind Hollywood's science-fiction fantasies to assess the real risks humanity faces from potential impacts of both comets and asteroids. For everyone interested in astronomy, this exciting book reveals the secrets of the Great Comets and provides essential tools for keeping up to date with comet discoveries in the future. Robert Burnham has been an amateur astronomer since the mid-1950s. He has been a senior editor of Astronomy magazine (1986-88) and is the author of many books and CD-ROMS, including Comet Hale-Bopp: Find and Enjoy the Great Comet and Comet Explorer.

  6. Investigating the Effects of Temperature on the Signatures of Shocks Propagated Through Impacts into Minerals Found in Comets and Asteroids

    Science.gov (United States)

    Lederer, Susan M.; Jensen, E. A.; Fane, M.; Smith, D. C.; Holmes, J.; Keller, L. P.; Lindsay, S. S.; Wooden, D. H.; Cintala, M. J.; Zolensky, M. E.

    2015-01-01

    Comets and asteroids are subjected to extremely cold conditions throughout their lifetimes. During their sojourns in the solar system, they are subjected to collisions at speeds that are easily capable of generating shock waves in their constituent materials. In addition to ices, more common silicate minerals such as olivines and pyroxenes are important components of these objects. The collision-induced shocks could affect the spectral signatures of those mineral components, which could in turn be detected telescopically. We have embarked on a project to determine how impact-generated shock might affect the reflectance spectra and structures of select silicates as both impact speed and target temperature are varied systematically. While the effects of impact speed (in the form of shock stress) on numerous materials have been and continue to be studied, the role of target temperature has received comparatively little attention, presumably because of the operational difficulties it can introduce to experimentation. Our experiments were performed with the vertical gun in the Experimental Impact Laboratory of the Johnson Space Center. A liquid-nitrogen system was plumbed to permit cooling of the target container and its contents under vacuum to temperatures as low as -100 C (173 K). Temperatures were monitored by thermocouples mounted on the outside of the target container. Because those sensors were not in contact with the target material at impact, the measured temperatures are treated as lower limits for the actual values. Peridot (Mg-rich olivine) and enstatite (Mg-rich orthopyroxene) were used as targets, which involved the impact of alumina (Al2O3) spheres at speeds of 2.0 - 2.7 km s(exp -1) and temperatures covering 25 C to -100 C (298 K to 173 K). We have begun collecting and analyzing data in the near to mid-IR with a Fourier-transform infrared spectrometer, and preliminary analyses show that notable differences in absorption-band strength and position occur

  7. Dynamical Model for the Zodiacal Cloud and Sporadic Meteors

    Science.gov (United States)

    Nesvorný, David; Janches, Diego; Vokrouhlický, David; Pokorný, Petr; Bottke, William F.; Jenniskens, Peter

    2011-12-01

    The solar system is dusty, and would become dustier over time as asteroids collide and comets disintegrate, except that small debris particles in interplanetary space do not last long. They can be ejected from the solar system by Jupiter, thermally destroyed near the Sun, or physically disrupted by collisions. Also, some are swept by the Earth (and other planets), producing meteors. Here we develop a dynamical model for the solar system meteoroids and use it to explain meteor radar observations. We find that the Jupiter Family Comets (JFCs) are the main source of the prominent concentrations of meteors arriving at the Earth from the helion and antihelion directions. To match the radiant and orbit distributions, as measured by the Canadian Meteor Orbit Radar (CMOR) and Advanced Meteor Orbit Radar (AMOR), our model implies that comets, and JFCs in particular, must frequently disintegrate when reaching orbits with low perihelion distance. Also, the collisional lifetimes of millimeter particles may be longer (gsim 105 yr at 1 AU) than postulated in the standard collisional models (~104 yr at 1 AU), perhaps because these chondrule-sized meteoroids are stronger than thought before. Using observations of the Infrared Astronomical Satellite to calibrate the model, we find that the total cross section and mass of small meteoroids in the inner solar system are (1.7-3.5) × 1011 km2 and ~4 × 1019 g, respectively, in a good agreement with previous studies. The mass input required to keep the zodiacal cloud in a steady state is estimated to be ~104-105 kg s-1. The input is up to ~10 times larger than found previously, mainly because particles released closer to the Sun have shorter collisional lifetimes and need to be supplied at a faster rate. The total mass accreted by the Earth in particles between diameters D = 5 μm and 1 cm is found to be ~15,000 tons yr-1 (factor of two uncertainty), which is a large share of the accretion flux measured by the Long Term Duration

  8. DYNAMICAL MODEL FOR THE ZODIACAL CLOUD AND SPORADIC METEORS

    International Nuclear Information System (INIS)

    Nesvorný, David; Vokrouhlický, David; Pokorný, Petr; Bottke, William F.; Janches, Diego; Jenniskens, Peter

    2011-01-01

    The solar system is dusty, and would become dustier over time as asteroids collide and comets disintegrate, except that small debris particles in interplanetary space do not last long. They can be ejected from the solar system by Jupiter, thermally destroyed near the Sun, or physically disrupted by collisions. Also, some are swept by the Earth (and other planets), producing meteors. Here we develop a dynamical model for the solar system meteoroids and use it to explain meteor radar observations. We find that the Jupiter Family Comets (JFCs) are the main source of the prominent concentrations of meteors arriving at the Earth from the helion and antihelion directions. To match the radiant and orbit distributions, as measured by the Canadian Meteor Orbit Radar (CMOR) and Advanced Meteor Orbit Radar (AMOR), our model implies that comets, and JFCs in particular, must frequently disintegrate when reaching orbits with low perihelion distance. Also, the collisional lifetimes of millimeter particles may be longer (∼> 10 5 yr at 1 AU) than postulated in the standard collisional models (∼10 4 yr at 1 AU), perhaps because these chondrule-sized meteoroids are stronger than thought before. Using observations of the Infrared Astronomical Satellite to calibrate the model, we find that the total cross section and mass of small meteoroids in the inner solar system are (1.7-3.5) × 10 11 km 2 and ∼4 × 10 19 g, respectively, in a good agreement with previous studies. The mass input required to keep the zodiacal cloud in a steady state is estimated to be ∼10 4 -10 5 kg s –1 . The input is up to ∼10 times larger than found previously, mainly because particles released closer to the Sun have shorter collisional lifetimes and need to be supplied at a faster rate. The total mass accreted by the Earth in particles between diameters D = 5 μm and 1 cm is found to be ∼15,000 tons yr –1 (factor of two uncertainty), which is a large share of the accretion flux measured by the

  9. Is An Asteroid Impact A Disaster? (Invited)

    Science.gov (United States)

    Davies, R. H.

    2009-12-01

    Looking Ahead - As far as the disaster management community is concerned the risk posed by the possibility of a large asteroid or comet impacting the earth is a subject of science fiction. What is ignored is that smaller objects, like what caused the Tunguska air-burst or what caused Meteor Crater in Arizona, U.S., occur much more frequently and could have significant consequences. In this, the era of “all hazards”, it is past time that the disaster management community has it in their response plan repertoire to address the possibility of a moderate to small meteor impact or air-burst over a U.S. city. It is the author’s opinion that if a small or moderate sized meteor impact or air-burst were to occur in the U.S. the event would assessed to be a nuclear detonation, an event for which there is actually response planning in place. The author further concludes that the confusion resulting from such an incorrect response would likely result in increased loss of life The presentation will suggest a process to develop a response plan for a small or moderate sized meteor impact or air-burst.

  10. A Meteor Shower Origin for Martian Methane

    Science.gov (United States)

    Fries, M.; Christou, A.; Archer, D.; Conrad, P.; Cooke, W.; Eigenbrode, J.; ten Kate, I. L.; Matney, M.; Niles, P.; Sykes, M.; Steele, A.; Treiman, A.

    2015-07-01

    We present and discuss the hypothesis that martian methane arises from a meteor shower source. Infall material produces methane by UV photolysis, generating localized plumes that occur after Mars/comet orbit interactions. This hypothesis is testable.

  11. Slow Meteors

    Science.gov (United States)

    Dubs, Martin; Sposetti, Stefano; Spinner, Roger; Booz, Beat

    2017-04-01

    Slow meteors are studied with video observations and spectroscopy. A comparison of their orbits and spectra points to a common origin. Although they do not belong to some meteor stream, they deserve to be studied in more detail. The present paper tries to make a first attempt to characterize the common properties of this class of meteors.

  12. Changing Speed of Comets

    Science.gov (United States)

    Follows, Mike

    2003-01-01

    It is shown that highly elliptical orbits, such as those of comets, can be explained well in terms of energy rather than forces. The principle of conservation of energy allows a comet's velocity to be calculated at aphelion and perihelion. An example asks students to calculate whether they can run fast enough to escape from a small asteroid.…

  13. Retinal meteor.

    Science.gov (United States)

    Venkatesh, Ramesh; Gurav, Prachi; Dave, Prachi Abhishek; Roy, Sankhadeep

    2017-09-01

    We describe a case of a 65-year old man diagnosed with retinal vasoproliferative tumour secondary to posterior uveitis. The fluorescein angiography shows an interesting meteor-like leak emanating from the tumour and rising towards the superior retina in the later frames of the angiogram. Pictorially, we call it the "Retinal Meteor" and also describe the possible mechanism for this pattern of leakage.

  14. Finding Long Lost Lexell's Comet: The Fate of the First Discovered Near-Earth Object

    Science.gov (United States)

    Ye, Quan-Zhi; Wiegert, Paul A.; Hui, Man-To

    2018-04-01

    Jupiter-family Comet D/1770 L1 (Lexell) was the first discovered Near-Earth Object (NEO) and passed the Earth on 1770 July 1 at a recorded distance of 0.015 au. The comet was subsequently lost due to unfavorable observing circumstances during its next apparition followed by a close encounter with Jupiter in 1779. Since then, the fate of D/Lexell has attracted interest from the scientific community, and now we revisit this long-standing question. We investigate the dynamical evolution of D/Lexell based on a set of orbits recalculated using the observations made by Charles Messier, the comet’s discoverer, and find that there is a 98% chance that D/Lexell remains in the solar system by the year of 2000. This finding remains valid even if a moderate non-gravitational effect is imposed. Messier’s observations also suggest that the comet is one of the largest known near-Earth comets, with a nucleus of ≳10 km in diameter. This implies that the comet should have been detected by contemporary NEO surveys regardless of its activity level if it has remained in the inner solar system. We identify asteroid 2010 JL33 as a possible descendant of D/Lexell, with a 0.8% probability of chance alignment, but a direct orbital linkage of the two bodies has not been successfully accomplished. We also use the recalculated orbit to investigate the meteors potentially originating from D/Lexell. While no associated meteors have been unambiguously detected, we show that meteor observations can be used to better constrain the orbit of D/Lexell despite the comet being long lost.

  15. Validation and Sensitivity Analysis of 3D Synthetic Aperture Radar (SAR) Imaging of the Interior of Primitive Solar System Bodies: Comets and Asteroids Project

    Data.gov (United States)

    National Aeronautics and Space Administration — To probe the interior of a comet, we are going to employ Radar Reflection Imager (RRI) Instrument on an orbiting platform. While orbiting around the comet at a safe...

  16. Halley's Comet: A Bibliography.

    Science.gov (United States)

    Freitag, Ruth S., Comp.

    Included in this bibliography are over 3,200 references to publications on Halley's Comet, its history, orbital motion, and physical characteristics, meteor streams associated with it, preparations for space missions to study it in 1986, and popular reaction to its appearances. Also cited are a few papers that, although they devote little…

  17. Lorentz-Shaped Comet Dust Trail Cross Section from New Hybrid Visual and Video Meteor Counting Technique - Implications for Future Leonid Storm Encounters

    Science.gov (United States)

    Jenniskens, Peter; Crawford, Chris; Butow, Steven J.; Nugent, David; Koop, Mike; Holman, David; Houston, Jane; Jobse, Klaas; Kronk, Gary

    2000-01-01

    A new hybrid technique of visual and video meteor observations was developed to provide high precision near real-time flux measurements for satellite operators from airborne platforms. A total of 33,000 Leonids. recorded on video during the 1999 Leonid storm, were watched by a team of visual observers using a video head display and an automatic counting tool. The counts reveal that the activity profile of the Leonid storm is a Lorentz profile. By assuming a radial profile for the dust trail that is also a Lorentzian, we make predictions for future encounters. If that assumption is correct, we passed 0.0003 AU deeper into the 1899 trailet than expected during the storm of 1999 and future encounters with the 1866 trailet will be less intense than. predicted elsewhere.

  18. Increasing Geminid meteor shower activity

    Science.gov (United States)

    Ryabova, G. O.; Rendtel, J.

    2018-03-01

    Mathematical modelling has shown that activity of the Geminid meteor shower should rise with time, and that was confirmed by analysis of visual observations 1985-2016. We do not expect any outburst activity of the Geminid shower in 2017, even though the asteroid (3200) Phaethon has a close approach to Earth in December of 2017. A small probability to observe dust ejected at perihelia 2009-2016 still exists.

  19. Meteorites, Bolides and Comets: A Tale of Inconsistency

    Science.gov (United States)

    Jakes, P.; Padevet, V.

    1992-07-01

    Inhomogeneity of cometary nuclei has been established through the observed disruptions of comets [1] and through the determination of dust particle composition during the encounter of the Vega and Giotto satellites with comet Halley [2,3,4]. The raisin bread model of cometary nuclei [5,6] assumes the presence of solid (rock) and dust particle material set in the volatile rich, ice- cemented material. Rock material may contribute to the formation of dust particles. Gombosi and Houpis [5] argued that only the composition of dust particles derived from the icy, volatile component of the comet were analyzed and implied thus that the third cometary component present (raisins/rocks) has not been examined. The compositions of the cometary (Halley) dust and the interplanetary dust particles (IDPs) are "chondritic" (Blanford et al., 1988). It is difficult, therefore to estimate the proportion of cometary to asteroid-derived dust in near Earth space, e.g., among the IDPs [7] unless other criteria are available. Bolide multistation photographic tracking allows the determination of the orbital preencounter parameters of solid bodies (0.01-100,000 kg in mass) with the Earth, and allows us to classify them according to their ablation coefficient (tau), penetration depth into the atmosphere (PE), theoretical densities (sigma), and terminal velocities (V(sub)E). Four groups are recognized (Table 1). Three of the type I bolides were recovered as ordinary chondrites (Pribram, Lost City, and Innisfree). Ceplecha [8] has shown that 38% of bolides (fireballs) come from cometary orbits (11% from highly eccentric orbits typical of new comets), but most of the bolides (62%) originate at asteroidal orbits. Seven of the 14 known meteoric showers could be attributed to known comets: N,S Taurids to 1970 P/Encke, Lyrids to 1861 I Thatcher-Beaker, Perseids to 1862 III Swift-Tuttle- Simons, Orionids to 1835 III P/Halley, Draconids to 1946 V P/Giacobini-Zinner, Leonids to 1966 I Tempel

  20. Expected Increase of Activity of Eta Aquariids Meteor Shower

    Science.gov (United States)

    Kulikova, N. V.; Chepurova, V. M.

    2018-04-01

    Analysis of the results of modeling disintegration of Comet 1P/Halley after its flare in 1991 has allowed us to predict an increase of the activity of the associated Eta Aquariids meteor shower in April-May 2018.

  1. The 2014 May Camelopardalid Meteor Shower

    Science.gov (United States)

    Cooke, Bill; Moser, Danielle

    2014-01-01

    On May 24, 2014 Earth will encounter multiple streams of debris laid down by Comet 209P LINEAR. This will likely produce a new meteor shower, never before seen. Rates predicted to be from 100 to 1000 meteors per hour between 2 and 4 AM EDT, so we are dealing with a meteor outburst, potentially a storm. Peak rate of 200 per hour best current estimate. Difficult to calibrate models due to lack of past observations. Models indicate mm size particles in stream, so potential risk to Earth orbiting spacecraft.

  2. Where Do Comets Come From?

    Science.gov (United States)

    Van Flandern, Tom

    1982-01-01

    Proposes a new origin for comets in the solar system, namely, that comets originated in the breakup of a body orbiting the sun in or near the present location of the asteroid belt in the relatively recent past. Predictions related to the theory are discussed. (Author/JN)

  3. Results of Lunar Impact Observations During Geminid Meteor Shower Events

    Science.gov (United States)

    Suggs, R. J.; Suggs, R. M.

    2015-01-01

    the lunar environment associated with larger lunar impactors, but also provides statistical data for verification and improving meteoroid prediction models. Current meteoroid models indicate that the Moon is struck by a sporadic meteoroid with a mass greater than 1 kg over 260 times per year. This number is very uncertain since observations for objects in this mass range are few. Factors of several times, higher or lower, are easily possible. Meteor showers are also present to varying degrees at certain times of the year. The Earth experiences meteor showers when encountering the debris left behind by comets, which is also the case with 2 the Moon. During such times, the rate of shower meteoroids can greatly exceed that of the sporadic background rate for larger meteoroids. Looking for meteor shower impacts on the Moon at about the same time as they occur on Earth will yield important data that can be fed into meteor shower forecasting models, which can then be used to predict times of greater meteoroid hazard on the Moon. The Geminids are one such meteor shower of interest. The Geminids are a major meteor shower that occur in December with a peak intensity occurring usually during the 13th and 14th of the month and appearing to come from a radiant in the constellation Gemini. The Geminids are interesting in that the parent body of the debris stream is an asteroid, which along with the Quadrantids, are the only major meteor showers not originating from a comet. The Geminids parent body, 3200 Phaethon, is about 5 km in diameter and has an orbit that has a 22deg inclination which intersects the main asteroid belt and has a perihelion less than half of Mercury's perihelion distance. Thus, its orbit crosses those of Mars, Earth, Venus, and Mercury. The Geminid debris stream is by far the most massive as compared to the others. When the Earth passes through the stream in mid-December, a peak intensity of approx. equal 120 meteors per hour can be seen. Because of the

  4. Asteroid Family Associations of Active Asteroids

    Science.gov (United States)

    Hsieh, Henry H.; Novaković, Bojan; Kim, Yoonyoung; Brasser, Ramon

    2018-02-01

    We report on the results of a systematic search for associated asteroid families for all active asteroids known to date. We find that 10 out of 12 main-belt comets (MBCs) and five out of seven disrupted asteroids are linked with known or candidate families, rates that have ∼0.1% and ∼6% probabilities, respectively, of occurring by chance, given the overall family association rate of 37% for asteroids in the main asteroid belt. We find previously unidentified family associations between 238P/Read and the candidate Gorchakov family, 311P/PANSTARRS and the candidate Behrens family, 324P/La Sagra and the Alauda family, 354P/LINEAR and the Baptistina family, P/2013 R3-B (Catalina-PANSTARRS) and the Mandragora family, P/2015 X6 (PANSTARRS) and the Aeolia family, P/2016 G1 (PANSTARRS) and the Adeona family, and P/2016 J1-A/B (PANSTARRS) and the Theobalda family. All MBCs with family associations belong to families that contain asteroids with primitive taxonomic classifications and low average reported albedos (\\overline{{p}V}≲ 0.10), while disrupted asteroids with family associations belong to families that contain asteroids that span wider ranges of taxonomic types and average reported albedos (0.06composition (i.e., whether an object is likely to contain ice), while disrupted asteroid activity is not as sensitive to composition. Given our results, we describe a sequence of processes by which the formation of young asteroid families could lead to the production of present-day MBCs.

  5. Study of the Dynamics of Meteoroids Through the Earth's Atmosphere and Retrieval of Meteorites: The Mexican Meteor Network

    Science.gov (United States)

    Cordero Tercero, M. G.; Farah Simon, A.; Velazquez-Villegas, F.

    2016-12-01

    When a comet , asteroid or meteoroid impact with a planet several things can happen depending on the mass, velocity and composition of the impactor, if the planet or moon has an atmosphere or not, and the angle of impact. On bodies without an atmosphere like Mercury or the Moon, every object that strikes their surfaces produces impact craters with sizes ranging from centimeters to hundreds and even thousands of kilometers across. On bodies with an atmosphere, this encounter can produce impact craters, meteorites, meteors and fragmentation. Each one of these phenomena is interesting because they provide information about the surfaces and the geological evolution of solar system bodies. Meteors are luminous wakes on the sky due to the interaction between the meteoroid and the Earth's atmosphere. A meteoroid is asteroidal or cometary material ranging in size from 2 mm to a few tens of meters. The smallest tend to evaporate at heights between 80 and 120 km. Objects of less than 2 mm are called micrometeorites. If the meteor brightness exceeds the brightness of Venus, the phenomenon is called a bolide or fireball. If a meteoroid, or a fragment of it, survives atmospheric ablation and it can be recovered on the ground, that piece is called a meteorite. Most meteoroids 2 meters long fragment suddenly into the atmosphere, it produces a shock wave that can affect humans and their environment like the Chelyabinsk event occurred on February 15, 2013 an two less energetic events in Mexico in 2010 and 2011. To understand the whole phenomenon, we proposed a video camera network for observing meteors. The objectives of this network are to: a) contribute to the study of the fragmentation of meteoroids in the Earth's atmosphere, b) determine values of important physical parameters; c) study seismic waves produced by atmospheric shock waves, d) study the dynamics of meteoroids and f) recover and study meteorites. During this meeting, the progress of the project will be presented.

  6. Monte Carlo modeling and meteor showers

    International Nuclear Information System (INIS)

    Kulikova, N.V.

    1987-01-01

    Prediction of short lived increases in the cosmic dust influx, the concentration in lower thermosphere of atoms and ions of meteor origin and the determination of the frequency of micrometeor impacts on spacecraft are all of scientific and practical interest and all require adequate models of meteor showers at an early stage of their existence. A Monte Carlo model of meteor matter ejection from a parent body at any point of space was worked out by other researchers. This scheme is described. According to the scheme, the formation of ten well known meteor streams was simulated and the possibility of genetic affinity of each of them with the most probable parent comet was analyzed. Some of the results are presented

  7. Meteor Beliefs Project: ``Year of Meteors''

    Science.gov (United States)

    McBeath, Alastair; Drobnock, George J.; Gheorghe, Andrei Dorian

    2011-10-01

    We present a discussion linking ideas from a modern music album by Laura Veirs back to a turbulent time in American history 150 years ago, which inspired poet Walt Whitman to compose his poem "Year of Meteors", and the meteor beliefs of the period around 1859-1860, when collection of facts was giving way to analyses and theoretical explanations in meteor science.

  8. The Meteor Meter.

    Science.gov (United States)

    Eggensperger, Martin B.

    2000-01-01

    Introduces the Meteor Scatter Project (MSP) in which high school students build an automated meteor observatory and learn to monitor meteor activity. Involves students in activities such as radio frequency survey, antenna design, antenna construction, manual meteor counts, and computer board configuration and installation. (YDS)

  9. The return of the Andromedids meteor shower

    OpenAIRE

    Wiegert, Paul A.; Brown, Peter G.; Weryk, Robert J.; Wong, Daniel K.

    2012-01-01

    The Andromedid meteor shower underwent spectacular outbursts in 1872 and 1885, producing thousands of visual meteors per hour and described as `stars fell like rain' in Chinese records of the time. The shower originates from comet 3D/Biela whose disintegration in the mid-1800's is linked to the outbursts, but the shower has been weak or absent since the late 19th Century. This shower returned in December 2011 with a zenithal hourly rate of approximately 50, the strongest return in over a hund...

  10. Phobos and Deimos: A Potential Comet Connection

    Science.gov (United States)

    Lee, P.

    2017-07-01

    Phobos and Deimos are similar in size and spectrum to an exceptionally large and spectrally uncommon asteroid among near-Earth objects: 3552 Don Quixote, a D-type NEO that's a comet. The martian moons' potential link to comets is discussed.

  11. Origin of meteor swarms of the Arietid and Geminid types

    International Nuclear Information System (INIS)

    Lebedinets, V.N.

    1985-01-01

    The author proposes a physical mechanism for the formation of meteor swarms on orbits of small size and very small perihelion distance, similar to the orbits of Arietid and Geminid meteor swarms, which are rarely encountered among the larger bodies of the solar system, and he justifies the mechanism mathematically. He shows that comets can transfer to such orbits from orbits of large size during evaporation of their ice nuclei under the action of reactive drag

  12. EVIDENCE FOR COMET STORMS IN METEORITE AGES

    Energy Technology Data Exchange (ETDEWEB)

    Perlmutter, S.; Muller, R.A.

    1987-10-01

    Clustering of cosmic-ray exposure ages of H chondritic meteorites occurs at 7 {+-} 3 and 30 {+-} 6 Myr ago. There is independent evidence that comet storms have occurred at the same times, based on the fossil record of family and genus extinctions, impact craters and glass, and geomagnetic reversals. We suggest that H chondrites were formed by the impact of shower comets on asteroids. The duration of the most recent comet shower was {le} 4 Myr, in agreement with storm theory.

  13. Multi-instrumental observations of the 2014 Ursid meteor outburst

    Science.gov (United States)

    Moreno-Ibáñez, Manuel; Trigo-Rodríguez, Josep M.; Madiedo, José María; Vaubaillon, Jérémie; Williams, Iwan P.; Gritsevich, Maria; Morillas, Lorenzo G.; Blanch, Estefanía; Pujols, Pep; Colas, François; Dupouy, Philippe

    2017-06-01

    The Ursid meteor shower is an annual shower that usually shows little activity. However, its Zenith hourly rate sometimes increases, usually either when its parent comet, 8P/Tuttle, is close to its perihelion or its aphelion. Outbursts when the comet is away from perihelion are not common and outbursts when the comet is close to aphelion are extremely rare. The most likely explanation offered to date is based on the orbital mean motion resonances. The study of the aphelion outburst of 2000 December provided a means of testing that hypothesis. A new aphelion outburst was predicted for 2014 December. The SPanish Meteor Network, in collaboration with the French Fireball Recovery and InterPlanetary Observation Network, set up a campaign to monitor this outburst and eventually retrieve orbital data that expand and confirm previous preliminary results and predictions. Despite unfavourable weather conditions over the south of Europe over the relevant time period, precise trajectories from multistation meteor data recorded over Spain were obtained, as well as orbital and radiant information for four Ursid meteors. The membership of these four meteors to the expected dust trails that were to provoke the outburst is discussed, and we characterize the origin of the outburst in the dust trail produced by the comet in the year ad 1392.

  14. Incoming asteroid! what could we do about it?

    CERN Document Server

    Lunan, Duncan

    2014-01-01

    Lately there have been more and more news stories on objects from space – such as asteroids, comets, and meteors – whizzing past Earth. One even exploded in the atmosphere over a Russian city in 2012, causing real damage and injuries. Impacts are not uncommon in our Solar System, even on Earth, and people are beginning to realize that we must prepare for such an event here on Earth.   What if we knew there was going to be an impact in 10 years’ time? What could we do? It’s not so far in the future that we can ignore the threat, and not so soon that nothing could be done. The author and his colleagues set out to explore how they could turn aside a rock asteroid, one kilometer in diameter, within this 10-year timescale.   Having set themselves this challenge, they identified the steps that might be taken, using technologies that are currently under development or proposed. They considered an unmanned mission, a follow-up manned mission, and a range of final options, along with ways to reduce the worst...

  15. The impact and recovery of asteroid 2008 TC3

    Czech Academy of Sciences Publication Activity Database

    Jenniskens, P.; Shaddad, M.H.; Numan, D.; Elsi, S.; Kudola, A.M.; Zolensky, M.E.; Le, L.; Pravec, Petr; Borovička, Jiří; Charvát, Z.

    2009-01-01

    Roč. 458, č. 7237 (2009), s. 485-488 ISSN 0028-0836 Institutional research plan: CEZ:AV0Z10030501 Keywords : asteroid * meteor * meteor ite Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 34.480, year: 2009

  16. Atmospheric deceleration and light curves of Draconid meteors and implications for the structure of cometary dust

    Czech Academy of Sciences Publication Activity Database

    Borovička, Jiří; Spurný, Pavel; Koten, Pavel

    2007-01-01

    Roč. 473, č. 2 (2007), s. 661-672 ISSN 0004-6361 R&D Projects: GA ČR GA205/05/0543; GA AV ČR KJB300030502 Institutional research plan: CEZ:AV0Z10030501 Keywords : meteor * meteor oid * comet Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 4.259, year: 2007

  17. 3D Imaging Cubesat Lidar for Asteroid and Planetary Sciences, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA is actively pursuing guidance and control light detection and ranging (lidar) systems for upcoming exploration missions including asteroid, comet, planet, and...

  18. Near-Earth Asteroid Tracking (NEAT) Program

    Science.gov (United States)

    Helin, Eleanor F.; Pravdo, Steven H.; Rabinowitz, David L.; Lawrence, Kenneth J.

    1997-01-01

    The discoveries of near-Earth asteroids (NEA's) and comets have increased enormously over the last 10-20 years. This is a consequence in large par; of the success of programs that have systematically searched for these objects. These programs have been motivated by the relationships of NEA's to terrestrial impacts, meteorites, comets, and their relative accessibility to spacecraft missions. This paper will review the long-term Palomar Planet Crossing Asteroid Survey (PCAS) a photographic program and the current Near-Earth Asteroid Tracking (NEAT) system NASA's new electronic detection program. The primary goal of NEAT is to discover and inventory near-Earth asteroids and comets, collectively called near-Earth objects or NEO's, larger than 1 km in size. Details of the NEAT system and program results are presented and discussed.

  19. State-of-the-art meteor observing

    Science.gov (United States)

    Campbell-Brown, M.

    2014-07-01

    Meteors are an excellent way to sample the local population of small asteroidal and cometary material. Various methods are used to calculate the trajectory, energy, mass and orbit of meteoroids which collide with the atmosphere. Optical methods, including photographic and video observations, can provide information on how meteoroids ablate in the atmosphere, and from this their chemical and physical properties can be inferred. New observing systems have higher resolution than ever before, allowing details as small as a few meters to be distinguished in some cases (e.g. Weryk et al. 2013), and some optical systems are equipped with spectral detectors which allow the atomic composition of the meteoroids to be obtained. Computer automation of both the observing and data reduction process has become much more practical recently. Meteor patrol radars are capable of observing thousands of meteor orbits every day, allowing the details of the distribution of meteoroids at 1 au to be found (e.g. Brown et al. 2010). Radars can operate in daylight and through clouds, providing observations when optical methods fail. High power, large aperture radars allow the ionization curves of very small meteors to be used in the same way as optical light curves, and can also produce precise orbits for meteoroids (Kero et al. 2012). Other methods used to observe meteors, including infrasound, can estimate their position in the atmosphere and their energy, and are particularly useful for very bright fireballs (Ens et al., 2012). Recent advances in meteor observing techniques will be reviewed, including the systematic tracking of meteors with computer guided mirrors and a telescope, and multistation patrol radar observations.

  20. Observing comets

    CERN Document Server

    James, Nick

    2003-01-01

    Since comet Shoemaker-Levy collided with the planet Jupiter with stupendous force in 1994 there has been an upsurge of amateur interest in comets Most comets are first discovered by amateur astronomers because there are so many amateurs looking for them, and techniques and instruments have improved dramatically in the past few years After a short but detailed introduction to the comets themselves Nick James and Gerald North describe comet hunting, photographing and imaging comets, and digital image processing The use of computers for orbital calculations and even helping to discover new comets is given a full chapter, as are advanced techniques including comet photometry and spectroscopy This comprehensive book has an accompanying CD-ROM and is at once a "primer" for comet hunters and a reference text for more advanced amateur astronomers

  1. Survival of Glycolaldehyde and Production of Sugar Compounds via Comet Impact Delivery

    Science.gov (United States)

    Zellner, N.; McCaffrey, V.; Crake, C.; Butler, J.; Robbins, J.; Fodor, A.

    2017-12-01

    Impact experiments using glycolaldehyde (GLA), a two-carbon sugar precursor that has been detected in regions of the interstellar medium and on comets, have been conducted at the Experimental Impact Laboratory at NASA's Johnson Space Center. Samples of GLA and GLA mixed with montmorillonite clays were subjected to the pressure conditions that are found during impact delivery of biomolecules by comets, asteroids, or meteors; pressures ranged from 4.5 GPa to 25 GPa. Results show that large amounts of GLA survived the impacts and moderate amounts of threose, erythrose, and glycolic acid were produced in these impacts. Total amounts are dependent on impact pressure. Ethylene glycol, a reduced variant of GLA that has also been detected in the interstellar medium and on comets, was also produced. The results of these experimental impacts provide evidence that large amounts of GLA, EG, and other biomolecules were available on habitable moons or planets, especially during the era of late heavy bombardment ( 4.2 to 3.7 billion years ago) when life may have been developing on Earth. The presence and availability of these biomolecules, under appropriate conditions, may be important for understanding the origin of life as we know it. Glycolaldehyde in particular, may be an important molecule in the production of ribose, the five-carbon sugar in RNA.

  2. 2015 Barcelona Asteroid Day

    CERN Document Server

    Gritsevich, Maria; Palme, Herbert

    2017-01-01

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

  3. Meteoroid Streams from Sunskirter Comet Breakup

    Science.gov (United States)

    Jenniskens, P. M.

    2012-12-01

    In its first year of operations, the CAMS project (Cameras for Allsky Meteor Surveillance) has measured 47,000 meteoroid orbits at Earth, including some that pass the Sun as close as 0.008 AU. The population density increases significantly above perihelion distance q = 0.037 AU. Meteoroid streams are known with q about 0.1 AU. The Sun has a profound effect on comets that pass at 0.04-0.16 AU distance, called the sunskirter comets. SOHO and STEREO see families of small comets called the Marsden and Kracht groups. Sunlight is efficiently scattered by small 10-m sized fragments, making those fragments visible even when far from Earth. These comet groups are associated with meteor showers on Earth, in particular the Daytime Arietids and Delta Aquariids. All are related to 96P/Machholz, a highly inclined short-period (5.2 year) Jupiter family comet that comes to within 0.12 AU from the Sun, the smallest perihelion distance known among numbered comets. The proximity of the Sun speeds up the disintegration process, providing us a unique window on this important decay mechanism of Jupiter family comets and creating meteoroid streams. These are not the only sunskirting comets, however. In this presentation, we will present CAMS observations of the complete low-q meteoroid population at Earth and review their association with known parent bodies.

  4. Cometary Volatiles and the Origin of Comets

    Science.gov (United States)

    A'Hearn, Michael F.; Feaga, Lori M.; Keller, H. Uwe; Kawakita, Hideyo; Hampton, Donald L.; Kissel, Jochen; Klaasen, Kenneth P.; McFadden, Lucy A.; Meech, Karen J.; Schultz, Peter H.; hide

    2012-01-01

    We describe recent results on the CO/C02/H2O composition of comets and compare these with models of the protoplanetary disk. We argue that the cometary observations require reactions on grain surfaces to convert CO to CO2 and also require formation between the CO and CO2 snow lines. This then requires very early mixing of cometesimals in the protoplanetary disk analogous to the mixing described for the asteroid belt by Walsh and Morbidelli. We suggest that most comets formed in the region of the giant planets. the traditional source of the Oort-cloud comets but not of the Jupiter-family comets

  5. Meteor observation by the Kyoto meteor radar

    International Nuclear Information System (INIS)

    Kato, S.; Tsuda, T.

    1987-01-01

    The Kyoto Meteor Radar is a monostatic coherent pulsed Doppler radar operating on the frequency of 31.57 MH. The system is computer controlled and uses radio interferometry for echo height determination. The antenna, an improvement, can be directed either to the north or the east. The system has been continuously collecting data on winds at meteor heights by radar observation. The meteor echo rate was also measured, the echo rate distribution with height and the daily variation in height integrated echo rate are discussed. Investigations of atmospheric tides are being pursued by cooperative observations. A novel approach to the study of gravity waves was attempted using the meteor radar which is able to detect the horizontal propagation of the waves by observing the changing phase through the region illuminated by the radar

  6. The 2014 KCG Meteor Outburst: Clues to a Parent Body

    Science.gov (United States)

    Moorhead, Althea V.; Brown, Peter G.; Spurny, Pavel; Cooke, William J.

    2015-01-01

    The Kappa Cygnid (KCG) meteor shower exhibited unusually high activity in 2014, producing ten times the typical number of meteors. The shower was detected in both radar and optical systems and meteoroids associated with the outburst spanned at least five decades in mass. In total, the Canadian Meteor Orbit Radar, European Network, and NASA All Sky and Southern Ontario Meteor Network produced thousands of KCG meteor trajectories. Using these data, we have undertaken a new and improved characterization of the dynamics of this little-studied, variable meteor shower. The Cygnids have a di use radiant and a significant spread in orbital characteristics, with multiple resonances appearing to play a role in the shower dynamics. We conducted a new search for parent bodies and found that several known asteroids are orbitally similar to the KCGs. N-body simulations show that the two best parent body candidates readily transfer meteoroids to the Earth in recent centuries, but neither produces an exact match to the KCG radiant, velocity, and solar longitude. We nevertheless identify asteroid 2001 MG1 as a promising parent body candidate.

  7. Meteor trail spectra

    International Nuclear Information System (INIS)

    Ovezgeldyev, O.G.; Mukhamednazarov, S.; Shafiev, R.I.; Maltsev, N.V.

    1987-01-01

    Meteor radiation appears as a result of collisions between meteoroid atoms and air molecules. Depending on duration, this radiation is usually divided into the following types: radiation of the meteor head; radiation of a coma surrounding or immediately following the meteor head; radiation of a trail formed as a result of fragments lagging behind or by the afterglow; and radiation of a meteor train forming from a tail as a result of various chemical and dynamical processes. To investigate physical processes caused by each of the above types, it is necessary to obtain the corresponding experimental data. The physical processes of the radiation and the measurement of the experimental data is discussed

  8. Asteroid impact monitoring

    Directory of Open Access Journals (Sweden)

    Milani A.

    2006-01-01

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

  9. Mine Planning for Asteroid Orebodies

    Science.gov (United States)

    Gertsch, L. S.; Gertsch, R. E.

    2000-01-01

    Given that an asteroid (or comet) has been determined to contain sufficient material of value to be potentially economic to exploit, a mining method must be selected and implemented. This paper discusses the engineering necessary to bring a mine online, and the opportunities and challenges inherent in asteroid mineral prospects. The very important step of orebody characterization is discussed elsewhere. The mining methods discussed here are based on enclosing the asteroid within a bag in some fashion, whether completely or partially. In general, asteroid mining methods based on bags will consist of the following steps. Not all will be required in every case, nor necessarily in this particular sequence. Some steps will be performed simultaneously. Their purpose is to extract the valuable material from the body of the asteroid in the most efficient, cost-effective manner possible. In approximate order of initiation, if not of conclusion, the steps are: 1. Tether anchoring to the asteroid. 2. Asteroid motion control. 3. Body/fragment restraint system placement. 4. Operations platform construction. 5. Bag construction. 6. Auxiliary and support equipment placement. 7. Mining operations. 8. Processing operations. 9. Product transport to markets.

  10. Characterizing the 2016 Perseid Meteor Shower Outburst

    Science.gov (United States)

    Blaauw, R. C.; Moser, D. E.; Ehlert, S. R.; Kingery, A. M.; Molau, S.; Schult, C.; Stober, G.

    2017-01-01

    The Perseid meteor shower has been observed for millennia and known for its visually spectacular meteors and occasional outbursts. The Perseids were expected to outburst in 2016, primarily due to particles released during the 1862 and 1479 revolutions of Comet Swift-Tuttle. NASA's Meteoroid Environment Office predicted the timing, strength and duration of the outburst for spacecraft risk using the MSFC Meteoroid Stream Model. A double peak was predicted, with an outburst displaying a ZHR of 210 +/- 50 at 00:30 UTC Aug 12, and a traditional peak approximately 12 hours later with rates still heightened from the outburst. Video, visual, and radar observations taken worldwide by various entities were used to characterize the shower and compare to predictions.

  11. Origin of Short-Perihelion Comets

    Science.gov (United States)

    Guliyev, A. S.

    2011-01-01

    New regularities for short-perihelion comets are found. Distant nodes of cometary orbits of Kreutz family are concentrated in a plane with ascending node 76 and inclination 267 at the distance from 2 up to 3 a.u. and in a very narrow interval of longitudes. There is a correlation dependence between q and cos I concerning the found plane (coefficient of correlation 0.41). Similar results are received regarding to cometary families of Meyer, Kracht and Marsden. Distant nodes of these comets are concentrated close three planes (their parameters are discussed in the article) and at distances 1.4; 0.5; 6 a.u. accordingly. It is concluded that these comet groups were formed as a result of collision of parent bodies with meteoric streams. One more group, consisting of 7 comets is identified. 5 comet pairs are selected among sungrazers.

  12. MWR, Meteor Wind Radars

    Science.gov (United States)

    Roper, R. G.

    1984-01-01

    The requirements of a state of the art meteor wind radar, and acceptable comprises in the interests of economy, are detailed. Design consideration of some existing and proposed radars are discussed. The need for international cooperation in mesopause level wind measurement, such as that being fostered by the MAP GLOBMET (Global Meteor Observations System) project, is emphasized.

  13. Spectral properties of near-Earth asteroids on cometary orbits

    Science.gov (United States)

    Popescu, M.; Vaduvescu, O.; de Leon, J.; Boaca, I. L.; Gherase, R. M.; Nedelcu, D. A.; INT students, I. N. G.

    2017-09-01

    We studied the spectral distributions of near-Earth asteroids on cometary orbits (NEACOs) in order to identify potential dormant or extinct comets among these objects. We present the spectral observations for 19 NEACOs obtained with Isaac Newton Telescope and Infrared Telescope Facility (IRTF). Although initially classified as asteroid, one of our targets - 2007 VA85 was confirmed to be active comet 333P/LINEAR on its 2016 appearance. We found that the NEACOs population is a mixing of different compositional classes.

  14. THE RETURN OF THE ANDROMEDIDS METEOR SHOWER

    International Nuclear Information System (INIS)

    Wiegert, Paul A.; Brown, Peter G.; Weryk, Robert J.; Wong, Daniel K.

    2013-01-01

    The Andromedid meteor shower underwent spectacular outbursts in 1872 and 1885, producing thousands of visual meteors per hour and described as ''stars fell like rain'' in Chinese records of the time. The shower originates from comet 3D/Biela whose disintegration in the mid-1800's is linked to the outbursts, but the shower has been weak or absent since the late 19th century. This shower returned in 2011 December with a zenithal hourly rate of approximately 50, the strongest return in over a hundred years. Some 122 probable Andromedid orbits were detected by the Canadian Meteor Orbit Radar while one possible brighter Andromedid member was detected by the Southern Ontario Meteor Network and several single station possible Andromedids by the Canadian Automated Meteor Observatory. The shower outburst occurred during 2011 December 3-5. The radiant at R.A. +18° and decl. +56° is typical of the ''classical'' Andromedids of the early 1800s, whose radiant was actually in Cassiopeia. Numerical simulations of the shower were necessary to identify it with the Andromedids, as the observed radiant differs markedly from the current radiant associated with that shower. The shower's orbital elements indicate that the material involved was released before 3D/Biela's breakup prior to 1846. The observed shower in 2011 had a slow geocentric speed (V G = 16 km s –1 ) and was comprised of small particles: the mean measured mass from the radar is ∼5 × 10 –7 kg, corresponding to radii of 0.5 mm at a bulk density of 1000 kg m –3 . Numerical simulations of the parent comet indicate that the meteoroids of the 2011 return of the Andromedids shower were primarily ejected during 3D/Biela's 1649 perihelion passage. The orbital characteristics, radiant, and timing as well as the absence of large particles in the streamlet are all broadly consistent with simulations. However, simulations of the 1649 perihelion passage necessitate going back five Lyapunov times (which is only 25 yr for the

  15. The "silent world" of Comet 15P/Finlay

    CERN Document Server

    Beech, M; Jones, J

    1999-01-01

    Comet 15P/Finlay is unusual in that, contrary to ab initio expectations, it demonstrates no apparent linkage to any known meteor shower. Using data contained within the Electronic Atlas of Dynamical Evolutions of Short-Period Comets, the authors evaluate theoretical shower radiants for Comet 15P/Finlay, but find no evidence to link it to any meteoric anomalies in recorded antiquity. This result, however, must be tempered by the fact that any Comet 15P/Finlay- derived meteoroids will have a low, 16 km s/sup -1/, encounter velocity with Earth's atmosphere. Typically, therefore, one would expect mostly faint meteors to be produced during an encounter with a Comet 15P/Finlay-derived meteoroid stream. they have conducted a D- criterion survey of meteoroid orbits derived from three southern hemisphere meteor radar surveys conducted during the 1960s, and again they find no evidence for any Comet 15P/Finlay-related activity. Numerical calculations following the orbital evolution of hypothetical meteoroids ejected fro...

  16. Bolidozor radio meteor detection network

    OpenAIRE

    Jakub Kákona; Martin Kákona

    2015-01-01

    Radio meteor detection networks could improve knowledge about meteors under daylight or inconvenient weather conditions. We present novel approach to the meteor detection system. Hardware described in this poster has unique features for time synchronization of multiple nodes, therefore meteor trajectory calculation is possible in case of appropriate network deployment.

  17. Photometry of faint asteroids and satellites

    International Nuclear Information System (INIS)

    Degewij, J.

    1978-01-01

    The smaller asteroids, having diameters of about 1 km, appear to rotate faster than do the larger asteroids (approximately 200 km diameter). Most of the bodies may be nearly spherical, probably due to a collisional erosion process in the Main Belt of asteroids. The distributions of diameter versus number were studied for low albedo (C, for carbonaceous) and high albedo (S, for silicaceous) type asteroids in the main belt, down to diameters of 25 km. Among the smaller bodies the S type asteroids are relatively more abundant, probably due to greater crushing strength for S type asteroids. This indicates that both optical types have also different properties in the interior of the body. Areas with slightly different reflectivity over the surface of an asteroid were detected; the rotational light variation of asteroid 4 (Vesta) was found to be caused by spots on its surface. Colorimetry and infrared radiometry of some Hilda asteroids, Trojans and the fainter satellites of Jupiter and Saturn, all having diameters between 100 and 200 km, show that a mixture of types exist. If some asteroids are nearly expended nuclei of comets that lost most of their volatile gaseous material, then their cometary activity is expected to be extinct or at least weak. (Auth.)

  18. 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.

  19. A meteoric nightglow

    International Nuclear Information System (INIS)

    Gadsden, M.

    1980-01-01

    The original reports of sky glows during spectacular meteor showers in the nineteenth century leave some doubt whether the observers might not simply have been over-enthusiastic. The nightglow photometric data available for the sole spectacular shower so far in the twentieth century are against there being any noticeable atmospheric effects resulting from the deposition of the meteoric material; calculations confirm previously published conclusions that sunlight scattered from the meteor stream might be visible near the radiant or the anti-radiant but, with the sole exception of one observer of the 1833 Leonids, no reports have been made of such an area of light. (author)

  20. Optical electronics for meteor observations

    International Nuclear Information System (INIS)

    Shafiev, R.I.; Mukhamednazarov, S.; Atamas, I.A.

    1987-01-01

    Spectral observations of meteors have been carried out for several years using an optical electronics facility. Interest has centered on faint meteors and their trails in the period of intensive meteor showers. Over 800 meteors were registered during the observation period, with spectrograms obtained for 170 of these. A total of 86 meteors were photographed from two sites and for 25 of these spectrograms of the meteors as well as their trails were obtained. All meteors have undergone routine processing in order to determine atmospheric characteristics. Results are discussed

  1. The Discovery of Cometary Activity in Near-Earth Asteroid Don Quixote

    NARCIS (Netherlands)

    Mommert, Michael; Hora, Joseph L.; Harris, Alan W.; Reach, William T.; Emery, Joshua P.; Thomas, Cristina A.; Mueller, Michael; Cruikshank, Dale P.; Trilling, David E.; Delbo, Marco; Smith, Howard A.

    2014-01-01

    The near-Earth object (NEO) population, which mainly consists of fragments from collisions between asteroids in the main asteroid belt, is thought to include contributions from short-period comets as well. One of the most promising NEO candidates for a cometary origin is near-Earth asteroid (3552)

  2. Surface heterogeneity of small asteroids

    Science.gov (United States)

    Sasaki, Sho

    A rubble pile model of asteroid origin would predict averaged rather homogeneous surface of an asteroid. Previous spacecraft observations (mostly S-type asteroids) did not show large color/albedo variation on the surface. Vesta would be exceptional since HST observation suggested that its surface should be heterogeneous due to the impact excavation of the interior. As for a young asteroid (832) Karin (age being 5Ma), Sasaki et al. (2004) detected variation of infrared spectra which could be explained by the difference of the space weathering degree. They discussed the possibility of the survival of the old surface. However, the variation was not confirmed by later observation (Chapman et al., 2007; Vernazza et al., 2007). Recent observation of a small (550m) asteroid Itokawa by Hayabusa spacecraft revealed that Itokawa is heterogeneous in color and albedo although the overall rocky structure is considered as a rubble pile (Saito et al., 2006). The color difference can be explained by the difference of weathering degree (Ishiguro et al., 2008). The heterogeneity could be explained by mass movement caused by rapid rotation from YORP effect (Scheeres et al., 2007) or seismic shaking (Sasaki, 2006). Probably small silicate asteroids without significant regolith could have heterogeneous in color and albedo. On large asteroids (˜ a few 10km), regolith reaccumulation should have covered the underlying heterogeneity. References: Chapman, C. R. et al (2007) Icarus, 191, 323-329 Ishiguro, M. et al. (2008) MAPS, in press. Saito, J. et al. (2006) Science, 312, 1341-1344 Sasaki, S. (2006) in Spacecraft Reconnaissance of Asteroid and Comet Interiors Sasaki, T. et al (2004) Astrophys. J. 615, L161-L164 Scheeres, D. J. (2007) Icarus 188, 425-429 Vernazza, P. et al. (2007) Icarus 191, 330-336.

  3. Search for Active Main-Belt Asteroids: The SAMBA Project

    Science.gov (United States)

    Hsieh, H. H.; Jewitt, D.

    2005-08-01

    We are conducting a deep optical survey of selected main-belt asteroids in search of comet-like behavior (comae or dust trails) like that observed for apparent Themis-family asteroid 7968 Elst-Pizarro (also 133P/Elst-Pizarro, hereafter EP). The surprising find of comet-like dust emission by EP (Hsieh, Jewitt, and Fernández, 2004, AJ 127, 2997) can be explained if (1) EP is a comet that has somehow evolved onto an asteroidal orbit, perhaps via the influence of cometary outgassing, or (2) EP is a native member of the asteroid belt on which preserved ice has recently become exposed. If EP is indeed an icy asteroid and not a lost comet, we would not expect uniqueness. A search for objects exhibiting comet-like behavior in the main belt, particularly among the Themis family among which EP itself resides, could reveal other icy bodies. We will present preliminary results (including activity level limits) for over 100 Themis family asteroids imaged as part of just such a search that we are currently conducting using telescopes on Mauna Kea and Cerro Tololo.

  4. Spitzer identification of potentially active Near-Earth Asteroids

    Science.gov (United States)

    Mommert, Michael; Trilling, David; Hora, Joseph; Smith, Howard; Chesley, Steve; Emery, Josh; Farnocchia, Davide; Fazio, Giovanni; Harris, Alan; Mueller, Migo

    2017-04-01

    The separation between asteroids and comets has become less clear with the discovery of a small group of asteroids that display comet-like activity. While the activity is attributed to different mechanisms, some objects seem to activate close to the Sun. Near-Earth Asteroids (NEAs) come close to the Earth and the Sun, constituting a natural laboratory for the study of thermally induced activity. Two NEA sub-populations are especially suspected of being potentially active: dormant comets and near-Sun asteroids. We propose 12.4 hrs of Spitzer IRAC observations of 3 near-Sun asteroids and one dormant comet (3552) Don Quixote, about which we have already published. Our goals are (1) to search for activity in Don Quixote, which showed CO/CO2 activity during its previous apparition and (2) to search for activity and measure the diameters and albedos of the near-Sun asteroids. In combination with a funded ground-based observing program, our results will provide significant legacy value to the investigation of activity in near-Earth asteroids.

  5. Migration of Interplanetary Dust and Comets

    Science.gov (United States)

    Ipatov, S. I.; Mather, J. C.

    Our studies of migration of interplanetary dust and comets were based on the results of integration of the orbital evolution of 15,000 dust particles and 30,000 Jupiter-family comets (JFCs) [1-3]. For asteroidal and cometary particles, the values of the ratio β between the radiation pressure force and the gravitational force varied from 1000 and 1 microns. The probability of a collision of a dust particle started from an asteroid or JFC with the Earth during a lifetime of the particle was maximum at diameter d ˜100 microns. For particles started from asteroids and comet 10P, this maximum probability was ˜0.01. Different studies of migration of dust particles and small bodies testify that the fraction of cometary dust particles of the overall dust population inside Saturn's orbit is considerable and can be dominant: (1) Cometary dust particles produced both inside and outside Jupiter's orbit are needed to explain the observed constant number density of dust particles at 3-18 AU. The number density of migrating trans-Neptunian particles near Jupiter's orbit is smaller by a factor of several than that beyond Saturn's orbit. Only a small fraction of asteroidal particles can get outside Jupiter's orbit. (2) Some (less than 0.1%) JFCs can reach typical near-Earth object orbits and remain there for millions of years. Dynamical lifetimes of most of the former JFCs that have typical near-Earth object orbits are about 106 -109 yr, so during most of these times they were extinct comets. Such former comets could disintegrate and produce a lot of mini-comets and dust. (3) Comparison of the velocities of zodiacal dust particles (velocities of MgI line) based on the distributions of particles over their orbital elements obtained in our runs [3-4] with the velocities obtained at the WHAM observations shows that only asteroidal dust particles cannot explain these observations, and particles produced by comets, including high-eccentricity comets, are needed for such explanation

  6. Atmospheric trajectories and light curves of shower meteors

    Czech Academy of Sciences Publication Activity Database

    Koten, Pavel; Borovička, Jiří; Spurný, Pavel; Betlem, H.; Evans, S.

    2004-01-01

    Roč. 428, č. 2 (2004), s. 683-690 ISSN 0004-6361 R&D Projects: GA ČR GP205/02/P038; GA ČR GA205/02/0982; GA ČR GA205/03/1404 Institutional research plan: CEZ:AV0Z1003909 Keywords : meteors * meteoroids * general-comets Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 3.694, year: 2004

  7. Malaysian meteoric water line

    International Nuclear Information System (INIS)

    Md Shahid Ayub

    2006-01-01

    The quest for Malaysian meteoric water line began in 1981 when environmental isotope hydrology was introduced. In the 1980, and with the establishment of three stations at Pengkalan Chepa, Kepala Batas and Kuah, the Malaysian Meteoric Water Line acquired then was δD = 8δ 18 O + 12.68. With the addition of another four stations, by the end of 1990s, the Malaysian Meteoric Water Line for the decade was established as δD = 8 δ 18 O + 11.76. Taking the overall result between 1980 and mid 2000s the Malaysian Meteoric Water Line was established as δD = 8 δ 18 O + 13.255 and the weighted mean precipitation is (-7.64, -46.74). In establishing this meteoric water line it was observed that the higher altitude station manifested poorer stable isotopes content as compared to lower altitude station. It was also observed that as the amount of rain increased, the stable isotopes content would decrease and vice versa. The effect is reversed when the amount is due to monsoon rains and tropical storms. (Author)

  8. New meteor showers – yes or not?

    Science.gov (United States)

    Koukal, Jakub

    2018-01-01

    The development of meteor astronomy associated with the development of CCD technology is reflected in a huge increase in databases of meteor orbits. It has never been possible before in the history of meteor astronomy to examine properties of meteors or meteor showers. Existing methods for detecting new meteor showers seem to be inadequate in these circumstances. The spontaneous discovery of new meteor showers leads to ambiguous specifications of new meteor showers. There is a duplication of already discovered meteor showers and a division of existing meteor showers based on their own criteria. The analysis in this article considers some new meteor showers in the IAU MDC database.

  9. International Halley watch amateur observers' manual for scientific comet studies. Part 1: Methods

    Science.gov (United States)

    Edberg, S. J.

    1983-01-01

    The International Halley Watch is described as well as comets and observing techniques. Information on periodic Comet Halley's apparition for its 1986 perihelion passage is provided. Instructions are given for observation projects valuable to the International Halley Watch in six areas of study: (1) visual observations; (2) photography; (3) astrometry; (4) spectroscopic observations; (5) photoelectric photometry; and (6) meteor observations.

  10. On coagulation process in meteor trails

    International Nuclear Information System (INIS)

    Bergkhanov, M.

    1988-01-01

    Structure of the meteors processes of collisions of paricles formd after interaction of meteoric matter with the Earth atmosphere are shortly described. Equation describing coagulation in meteor trails is obtained. Primary and secondary particles of meteor nature, representing the source of polydisperse aerosol, exist in meteor zone. Coagulation in meteor trails can be referred to Brownian one

  11. Martian Meteor Crater

    Science.gov (United States)

    2004-01-01

    20 February 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a fairly young meteor impact crater on Mars that is about the same size ( 1 kilometer; 0.62 miles) as the famous Meteor Crater in northern Arizona, U.S.A. Like the Arizona crater, boulders of ejected bedrock can be seen on the crater's ejecta blanket and in the crater itself. This crater is located in the Aethiopis region of Mars near 4.7oN, 224.1oW. Sunlight illuminates the scene from the lower left.

  12. Video Meteor Fluxes

    Science.gov (United States)

    Campbell-Brown, M. D.; Braid, D.

    2011-01-01

    The flux of meteoroids, or number of meteoroids per unit area per unit time, is critical for calibrating models of meteoroid stream formation and for estimating the hazard to spacecraft from shower and sporadic meteors. Although observations of meteors in the millimetre to centimetre size range are common, flux measurements (particularly for sporadic meteors, which make up the majority of meteoroid flux) are less so. It is necessary to know the collecting area and collection time for a given set of observations, and to correct for observing biases and the sensitivity of the system. Previous measurements of sporadic fluxes are summarized in Figure 1; the values are given as a total number of meteoroids striking the earth in one year to a given limiting mass. The Gr n et al. (1985) flux model is included in the figure for reference. Fluxes for sporadic meteoroids impacting the Earth have been calculated for objects in the centimeter size range using Super-Schmidt observations (Hawkins & Upton, 1958); this study used about 300 meteors, and used only the physical area of overlap of the cameras at 90 km to calculate the flux, corrected for angular speed of meteors, since a large angular speed reduces the maximum brightness of the meteor on the film, and radiant elevation, which takes into account the geometric reduction in flux when the meteors are not perpendicular to the horizontal. They bring up corrections for both partial trails (which tends to increase the collecting area) and incomplete overlap at heights other than 90 km (which tends to decrease it) as effects that will affect the flux, but estimated that the two effects cancelled one another. Halliday et al. (1984) calculated the flux of meteorite-dropping fireballs with fragment masses greater than 50 g, over the physical area of sky accessible to the MORP fireball cameras, counting only observations in clear weather. In the micron size range, LDEF measurements of small craters on spacecraft have been used to

  13. Comparison of comet 81P/Wild 2 dust with interplanetary dust from comets.

    Science.gov (United States)

    Ishii, Hope A; Bradley, John P; Dai, Zu Rong; Chi, Miaofang; Kearsley, Anton T; Burchell, Mark J; Browning, Nigel D; Molster, Frank

    2008-01-25

    The Stardust mission returned the first sample of a known outer solar system body, comet 81P/Wild 2, to Earth. The sample was expected to resemble chondritic porous interplanetary dust particles because many, and possibly all, such particles are derived from comets. Here, we report that the most abundant and most recognizable silicate materials in chondritic porous interplanetary dust particles appear to be absent from the returned sample, indicating that indigenous outer nebula material is probably rare in 81P/Wild 2. Instead, the sample resembles chondritic meteorites from the asteroid belt, composed mostly of inner solar nebula materials. This surprising finding emphasizes the petrogenetic continuum between comets and asteroids and elevates the astrophysical importance of stratospheric chondritic porous interplanetary dust particles as a precious source of the most cosmically primitive astromaterials.

  14. Whence comets?

    Science.gov (United States)

    A'Hearn, Michael F

    2006-12-15

    Recent advances in cometary science have indicated the importance of mixing of materials in the disk where the planets of our solar system formed. Now, the results from the Stardust Discovery Mission unambiguously show that even more extensive and earlier mixing of the material took place, raising new challenges for theories of the protoplanetary disk and the formation of comets.

  15. Anatomy of an Asteroid Breakup

    Science.gov (United States)

    Kohler, Susanna

    2017-05-01

    A team of scientists has observed the breakup of an asteroid as it orbits the Sun. In a new study, they reveal what theyve learned from their ground- and space-based observations of this disintegration.These Hubble images show the fragments of R3 in higher resolution over the span of October 2013 to February 2014. [Jewitt et al. 2017]Observations of DisintegrationActive asteroids are objects that move on asteroid-like orbits while displaying comet-like behavior. The cause of their activity can vary ranging from outgassing as the asteroid heats up in its solar approach, to expelled debris from a collision, to the entire asteroid flying apart because its spinning too fast.Led by David Jewitt (University of California at Los Angeles), a team of scientists has analyzed observations of the disintegrating asteroid P/2013 R3. The observations span two years and were made by a number of telescopes, including Hubble, Keck (in Hawaii), Magellan (in Chile), and the Very Large Telescope (in Chile).A schematic diagram of the different fragments of R3 and how they relate to each other. Black numbers estimate the fragment separation velocities; red numbers estimate the separation date. [Jewitt et al. 2017]Jewitt and collaborators then used these observations and a bit of modeling to understand what asteroid R3 was like originally, what its pieces are doing now, and what caused it to break up.Cause of the BreakupThe team found that P/2013 R3 broke up into at least 13 pieces, the biggest of which was likely no more than 100-200 meters in size. The original asteroid was probably less than 400 m in radius.By measuring the velocities of the fragments in the various observations, Jewitt and collaborators were able to work backward to determine when each piece broke off. They found that the fragmentation process was spread out over the span of roughly 5 months suggesting that the asteroids breakup wasnt impact-related (otherwise the fragmentation would likely have been all at once

  16. Tumbling asteroids

    Czech Academy of Sciences Publication Activity Database

    Pravec, Petr; Harris, A. W.; Scheirich, Peter; Kušnirák, Peter; Kotková, Lenka; Hergenrother, C.; Mottola, S.; Hicks, M. D.; Masi, G.; Krugly, Yu. N.; Shevchenko, V. G.; Nolan, M. C.; Howell, E. S.; Kaasalainen, M.; Galád, Adrián; Brown, P.; DeGraff, D. R.; Lambert, J.V.; Cooney, W.R.; Foglia, S.

    2005-01-01

    Roč. 1, č. 173 (2005), s. 108-131 ISSN 0019-1035 R&D Projects: GA AV ČR IAA3003204 Keywords : near-Earth objects * fast-rotating asteroids Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 3.244, year: 2005

  17. Dust bands in the asteroid belt

    International Nuclear Information System (INIS)

    Sykes, M.V.; Greenberg, R.; Dermott, S.F.; Nicholson, P.D.; Burns, J.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. 32 refs

  18. Colour, albedo and nucleus size of Halley's comet

    Science.gov (United States)

    Cruikshank, D. P.; Tholen, D. J.; Hartmann, W. K.

    1985-01-01

    Photometry of Halley's comet in the B, J, V, and K broadband filters during a time when the coma was very weak and presumed to contribute negligibly to the broadband photometry is reported. The V-J and J-K colors suggest that the color of the nucleus of Halley's comet is similar to that of the D-type asteroids, which in turn suggests that the surface of the nucleus has an albedo less than 0.1.

  19. Meteors in Australian Aboriginal Dreamings

    Science.gov (United States)

    Hamacher, Duane W.; Norris, Ray P.

    2010-06-01

    We present a comprehensive analysis of Australian Aboriginal accounts of meteors. The data used were taken from anthropological and ethnographic literature describing oral traditions, ceremonies, and Dreamings of 97 Aboriginal groups representing all states of modern Australia. This revealed common themes in the way meteors were viewed between Aboriginal groups, focusing on supernatural events, death, omens, and war. The presence of such themes around Australia was probably due to the unpredictable nature of meteors in an otherwise well-ordered cosmos.

  20. ISO's analysis of Comet Hale-Bopp

    Science.gov (United States)

    1997-03-01

    of the comet's dust and vapour, and also rates of escape of vapour, which will help in assessing the loss of material from Comet Hale-Bopp during this visit to the Sun's vicinity. "Watch out for some fascinating news," says Thijs de Graauw of Groningen University, who is in charge of the SWS instrument used in this study. "What excites me is the opportunity we shall have to compare dusty Comet Hale-Bopp, seen in the Solar System, with dusty objects far away among the stars which seem to be made of similar materials. Infrared astronomy has a special ability to unify cosmic chemistry at all scales from little dust grains in the Earth's vicinity to vast and distant galaxies." The dust itself interests the infrared astronomers, not least because their view of the Universe at large is spoiled to some extent by dust left behind by comets. Together with fine debris from asteroids, the comet dust makes a bright infrared band around the sky, which corresponds with the zodiacal light sometimes seen by eye, slanting above the horizon at twilight. ISO's predecessor, the US-Dutch-UK infrared astronomical satellite IRAS, found trails of comet dust much longer and more persistent than the familiar comet tails. ISO has seen a trail from Comet Kopff. By detecting dust grains that are typically much larger than those seen by visible light, ISO scientists hope to learn more about the dust's long-term behaviour in the Solar System. A series of images of Comet Hale-Bopp, obtained by the camera ISOCAM in October 1996, is the subject of continuing analysis. Leading this work in progress is Philippe Lamy of Marseille, France. "We hope to unveil the nucleus of the comet," Professor Lamy explains. "In principle, the Hubble Space Telescope can see finer details by visible light, but the contrast of the nucleus against the bright surrounding coma is superior at infrared wavelengths. This is because the thermal emission from the nucleus is very large and can be detected thanks to the high

  1. Current trends in meteor spectroscopy

    International Nuclear Information System (INIS)

    Millman, P.H.

    1983-01-01

    In the post-war period, a general interest in the upper atmosphere led to the development of more efficient meteor cameras and later, electronic image-intensification systems recording on video tape. As a result several thousand meteor spectra are now available. In this paper, the general nature of meteor spectra is discussed as is the resolution in these spectra, the height and velocity of the meteor stream, the chemical abundance and photometric techniques for the determination of absolute luminosities in the spectrum lines. (Auth.)

  2. Meteors and how to observe them

    CERN Document Server

    Lunsford, Robert

    2009-01-01

    No two meteor showers are alike, and their variation depends on current conditions and the observer's location. This introduction to the art of meteor observing explains how best to view meteor activity under all conditions and from all locations.

  3. Meteor Beliefs Project: Meteoric references in Ovid's Metamorphoses

    Science.gov (United States)

    Gheorghe, A. D.; McBeath, A.

    2003-10-01

    Three sections of Ovid's Metamorphoses are examined, providing further information on meteoric beliefs in ancient Roman times. These include meteoric imagery among the portents associated with the death of Julius Caesar, which we mentioned previously from the works of William Shakespeare (McBeath and Gheorghe, 2003b).

  4. The EISCAT meteor code

    Directory of Open Access Journals (Sweden)

    G. Wannberg

    2008-08-01

    Full Text Available The EISCAT UHF system has the unique capability to determine meteor vector velocities from the head echo Doppler shifts measured at the three sites. Since even meteors spending a very short time in the common volume produce analysable events, the technique lends itself ideally to mapping the orbits of meteors arriving from arbitrary directions over most of the upper hemisphere.

    A radar mode optimised for this application was developed in 2001/2002. A specially selected low-sidelobe 32-bit pseudo-random binary sequence is used to binary phase shift key (BPSK the transmitted carrier. The baud-length is 2.4 μs and the receiver bandwidth is 1.6 MHz to accommodate both the resulting modulation bandwidth and the target Doppler shift. Sampling is at 0.6 μs, corresponding to 90-m range resolution. Target range and Doppler velocity are extracted from the raw data in a multi-step matched-filter procedure. For strong (SNR>5 events the Doppler velocity standard deviation is 100–150 m/s. The effective range resolution is about 30 m, allowing very accurate time-of-flight velocity estimates. On average, Doppler and time-of-flight (TOF velocities agree to within about one part in 103. Two or more targets simultaneously present in the beam can be resolved down to a range separation <300 m as long as their Doppler shifts differ by more than a few km/s.

  5. Astrophotography Basics: Meteors, Comets, Eclipses, Aurorae, Star Trails. Revised.

    Science.gov (United States)

    Eastman Kodak Co., Rochester, NY.

    This pamphlet gives an introduction to the principles of astronomical picture-taking. Chapters included are: (1) "Getting Started" (describing stationary cameras, sky charts and mapping, guided cameras, telescopes, brightness of astronomical subjects, estimating exposure, film selection, camera filters, film processing, and exposure for…

  6. Investigation of impact materials around Barringer Meteor Crater by SEMEDX and micro-PIXE techniques

    International Nuclear Information System (INIS)

    Uzonyi, I.; Kiss, A.Z.; Cserhati, C.; Daroczi, L.

    2008-01-01

    Complete text of publication follows. Up to date (2008), 174 terrestrial impact craters have been explored on the Earth's surface. They were created by hitting asteroids, meteorites and/or comets. The most famous and well-preserved meteorite crater is the Barringer Meteor Crater in Arizona, USA which is approximately 50,000 years old. It was created by an iron meteorite. In recent years, much effort has been devoted to the elemental characterization of various impact materials collected in its near environment by the leadership of the late Prof. Gyula Szoeor. Especially, their Fe-rich inclusions were studied supposedly originated from the projectile of the impacted meteorite. In this report, results for some non-spherical, aggregate-like specimens are shown. The application of Scanning Electron Microscope combined with Energy Dispersive Xray Analysis (SEM-EDX) and a Scanning Nuclear Microprobe (SNM) is a powerful technique for the complex characterization of such materials. SEM provides the fine textural information and the concentration of the major elements. SNM with Particle Induced X-ray Emission (PIXE) method serves for the determination of both the major constituents and the important minor and trace elements such as the Platinum Group Elements (PGEs): Ru, Rh, Pd, etc. In this report analytical data are presented for S-Fe-Ni-Cu systems in order to feature the major characteristics of impact metamorphism of materials. A part of the work was presented in the 11th Int. Conf. on Nuclear Microprobe Technology and Applications (Hungary) and 71st Annual Meeting of the Meteoritical Society (Japan) conferences. Detailed results are under publication in a NIM B volume. Acknowledgements Support from the EU co-funded Economic Competitiveness Operative Programme GVOP- 3.2.1.-2004-04-0402/3.0, the Hungarian-Slovenian intergovernmental S and T cooperation program (SLO-16/2005 GVOP) as well as from the Hungarian Research Foundation (OTKA) under contract No T046579 are

  7. Infrasound detection of meteors

    Directory of Open Access Journals (Sweden)

    M.N. ElGabry

    2017-06-01

    The signals of these three meteors were detected by the infrasound sensors of the International Monitoring System (IMS of the Comprehensive Test Ban Treaty Organization (CTBTO. The progressive Multi Channel Technique is applied to the signals in order to locate these infrasound sources. Correlation of the recorded signals in the collocated elements of each array enables to calculate the delays at the different array element relative to a reference one as a way to estimate the azimuth and velocity of the coming infrasound signals. The meteorite infrasound signals show a sudden change in pressure with azimuth due to its track variation at different heights in the atmosphere. Due to movement of the source, a change in azimuth with time occurs. Our deduced locations correlate well with those obtained from the catalogues of the IDC of the CTBTO.

  8. Artificial meteor test towards: On-demand meteor shower

    Science.gov (United States)

    Abe, S.; Okajima, L.; Sahara, H.; Watanabe, T.; Nojiri, Y.; Nishizono, T.

    2016-01-01

    An arc-heated wind tunnel is widely used for ground-based experiments to simulate environments of the planetary atmospheric entry under hypersonic and high-temperature conditions. In order to understand details of a meteor ablation such as temperature, composition ratio and fragmentation processes, the artificial meteor test was carried out using a JAXA/ISAS arc-heated wind tunnel. High-heating rate around 30 MW/m2 and High-enthalpy conditions, 10000 K arc-heated flow at velocity around 6 km/s were provided. Newly developed artificial metallic meteoroids and real meteorites such as Chelyabinsk were used for the ablation test. The data obtained by near-ultraviolet and visible spectrograph (200 and 1100nm) and high-speed camera (50 μs) have been examined to develop more efficient artificial meteor materials. We will test artificial meteors from a small satellite in 2018.

  9. Jupiter approaching asteroids and their possibilities for activity

    Czech Academy of Sciences Publication Activity Database

    Galád, Adrián

    2005-01-01

    Roč. 326, č. 8 (2005), s. 709-715 ISSN 0004-6337 R&D Projects: GA AV ČR IAA3003204 Keywords : Asteroids * comets Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 0.871, year: 2005

  10. Comet and meteorite traditions of Aboriginal Australians

    Science.gov (United States)

    Hamacher, Duane W.

    2014-06-01

    This research contributes to the disciplines of cultural astronomy (the academic study of how past and present cultures understand and utilise celestial objects and phenomena) and geomythology (the study of geological events and the formation of geological features described in oral traditions). Of the hundreds of distinct Aboriginal cultures of Australia, many have oral traditions rich in descriptions and explanations of comets, meteors, meteorites, airbursts, impact events, and impact craters. These views generally attribute these phenomena to spirits, death, and bad omens. There are also many traditions that describe the formation of meteorite craters as well as impact events that are not known to Western science.

  11. Do comets C/1861 G1 (Thatcher) and C/1861 J1 (Great comet) have a common origin?

    Science.gov (United States)

    Branham, R. L.

    2015-10-01

    A new orbit is calculated for Comet C/1861 G1 (Thatcher), associated with the Lyrid meteor shower, to replace Oppolzer's orbit of 1864. The new orbit is based upon 649 observations, 326 in right ascension and 323 in declination, made between 11 April 1861 and 7 Sept. 1861. The final orbit uses residuals calculated with the Welsch weighting function. The comet's period of 416.87 ± 0.56 yr agrees with Oppolzer's period of 415 yr athough other elements such as the inclination differ. Although the post-perihelion residuals are relatively random, 52.1% probability of randomness, pre-perihelion residuals lack randomness indicating possible deviations from Keplerian motion caused by ejection of meteoritic material. Comet Thatcher is unrelated to the Great comet of 1861.

  12. Review of amateur meteor research

    Science.gov (United States)

    Rendtel, Jürgen

    2017-09-01

    Significant amounts of meteor astronomical data are provided by amateurs worldwide, using various methods. This review concentrates on optical data. Long-term meteor shower analyses based on consistent data are possible over decades (Orionids, Geminids, κ-Cygnids) and allow combination with modelling results. Small and weak structures related to individual stream filaments of cometary dust have been analysed in both major and minor showers (Quadrantids, September ε-Perseids), providing feedback to meteoroid ejection and stream evolution processes. Meteoroid orbit determination from video meteor networks contributes to the improvement of the IAU meteor data base. Professional-amateur cooperation also concerns observations and detailed analysis of fireball data, including meteorite ground searches.

  13. Search for OH(A–X) and detection of N2+(B–X) in ultraviolet meteor spectrum

    Czech Academy of Sciences Publication Activity Database

    Abe, S.; Ebizuka, N.; Yano, H.; Watanabe, J.; Borovička, Jiří

    2007-01-01

    Roč. 39, č. 4 (2007), s. 538-543 ISSN 0273-1177 Institutional research plan: CEZ:AV0Z10030501 Keywords : astrobiology * comets * meteor s Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 0.774, year: 2007

  14. Meteor magnitudes and enduring trains

    International Nuclear Information System (INIS)

    Baggaley, W.J.

    1978-01-01

    Using data associated with the sodium nightglow, it is possible to determine the minimum masses of meteoroids which might be expected to produce long-lived meteor trains. Such a procedure yields meteors having visual magnitudes in the range -2 to -5 depending on velocity. Since such values are in good accord with observation, the procedure provides important evidence regarding the source of enduring-train luminosity. (author)

  15. Meteor showers an annotated catalog

    CERN Document Server

    Kronk, Gary W

    2014-01-01

    Meteor showers are among the most spectacular celestial events that may be observed by the naked eye, and have been the object of fascination throughout human history. In “Meteor Showers: An Annotated Catalog,” the interested observer can access detailed research on over 100 annual and periodic meteor streams in order to capitalize on these majestic spectacles. Each meteor shower entry includes details of their discovery, important observations and orbits, and gives a full picture of duration, location in the sky, and expected hourly rates. Armed with a fuller understanding, the amateur observer can better view and appreciate the shower of their choice. The original book, published in 1988, has been updated with over 25 years of research in this new and improved edition. Almost every meteor shower study is expanded, with some original minor showers being dropped while new ones are added. The book also includes breakthroughs in the study of meteor showers, such as accurate predictions of outbursts as well ...

  16. Comet 'Bites the Dust' Around Dead Star

    Science.gov (United States)

    2006-01-01

    of dust. The data also demonstrate that this dust contains some of the same types of minerals found in comet Hale-Bopp. The findings tell a possible tale of solar system survival. Though the dust seen by Spitzer is likely from a comet that recently perished, its presence suggests that an icy distant ring of comets may still orbit the dead star. These data were collected by Spitzer's infrared spectrometer, an instrument that cracks light open like a geode, revealing its coveted components. In this spectrum, light from the white dwarf is on the left, at ultraviolet and visible wavelengths. The spectrum on the right, at infrared wavelengths longer than about 2 microns, shows much more light than can be explained by a white dwarf alone. The bump seen around a wavelength of 10 microns offers a clue to the source of this excess infrared light. It signifies the presence of silicate minerals, which are found in our own solar system on Earth, in sandy beaches, and in comets and asteroids. These silicate grains appear to be very small like those in comets, so astronomers favor the theory that a comet recently broke apart around the dead star.

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

    Science.gov (United States)

    Fernández, Julio A.; Sosa, Andrea; Gallardo, Tabaré; Gutiérrez, Jorge N.

    2014-08-01

    We analyze a sample of 139 near-Earth asteroids (NEAs), defined as those that reach perihelion distances q4.8 au), having Tisserand parameters 2family comets (JFCs) in near-Earth orbits, i.e. with q4.8 au of cometary origin, but it could be even lower if the NEAs in unstable orbits listed before turn out to be bona fide asteroids from the main belt. This study strengthens the idea that NEAs and comets essentially are two distinct populations, and that periods of dormancy in comets must be rare. Most likely, active comets in near-Earth orbits go through a continuous erosion process in successive perihelion passages until disintegration into meteoritic dust and fragments of different sizes. In this scenario, 289P/Blanpain might be a near-devolatized fragment from a by now disintegrated parent comet.

  18. Physical processes affecting the motion of small bodies in the solar system and their application to the evolution of meteor streams

    International Nuclear Information System (INIS)

    Williams, I.P.

    1983-01-01

    In addition to planetary perturbations, the small particles which make up a meteor stream are subject to outward radiation pressure and the Poynting-Robertson effect. New particles can also be generated in a stream through being released from the nucleus of a comet. The author summarises the main physical effects, discusses models for meteor stream evolution and gives a brief account of the observational data available. (Auth.)

  19. ASTEROID SPIN VECTORS

    Data.gov (United States)

    National Aeronautics and Space Administration — This is a tabulation of 526 determinations of asteroid pole orientations, covering 104 numbered asteroids, gathered from the literature from 1932 through 1995.

  20. ASTEROID LIGHTCURVE DERIVED DATA

    Data.gov (United States)

    National Aeronautics and Space Administration — This is a compilation of published rotational parameters derived from lightcurve data for asteroids, based on the Warner et al. (2009) Asteroid Lightcurve Database....

  1. A fast meteor detection algorithm

    Science.gov (United States)

    Gural, P.

    2016-01-01

    A low latency meteor detection algorithm for use with fast steering mirrors had been previously developed to track and telescopically follow meteors in real-time (Gural, 2007). It has been rewritten as a generic clustering and tracking software module for meteor detection that meets both the demanding throughput requirements of a Raspberry Pi while also maintaining a high probability of detection. The software interface is generalized to work with various forms of front-end video pre-processing approaches and provides a rich product set of parameterized line detection metrics. Discussion will include the Maximum Temporal Pixel (MTP) compression technique as a fast thresholding option for feeding the detection module, the detection algorithm trade for maximum processing throughput, details on the clustering and tracking methodology, processing products, performance metrics, and a general interface description.

  2. The January 7, 2015, superbolide over Romania and structural diversity of meter-sized asteroids

    Czech Academy of Sciences Publication Activity Database

    Borovička, Jiří; Spurný, Pavel; Grigore, V.I.; Svoreň, J.

    2017-01-01

    Roč. 143, SI (2017), s. 147-158 ISSN 0032-0633 R&D Projects: GA ČR(CZ) GA16-00761S Institutional support: RVO:67985815 Keywords : meteor * meteoroid * asteroid Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics OBOR OECD: Astronomy (including astrophysics, space science) Impact factor: 1.892, year: 2016

  3. Data base on physical observations of near-Earth asteroids and establishment of a network to coordinate observations of newly discovered near-Earth asteroids

    Science.gov (United States)

    Davis, D. R.; Chapman, C. R.; Campins, H.

    1990-01-01

    This program consists of two tasks: (1) development of a data base of physical observations of near-earth asteroids and establishment of a network to coordinate observations of newly discovered earth-approaching asteroids; and (2) a simulation of the surface of low-activity comets. Significant progress was made on task one and, and task two was completed during the period covered by this progress report.

  4. Disintegration of comet nuclei

    Science.gov (United States)

    Ksanfomality, Leonid V.

    2012-02-01

    The breaking up of comets into separate pieces, each with its own tail, was seen many times by astronomers of the past. The phenomenon was in sharp contrast to the idea of the eternal and unchangeable celestial firmament and was commonly believed to be an omen of impending disaster, especially for comets with tails stretching across half the sky. It is only now that we have efficient enough space exploration tools to see comet nuclei and even - in the particular case of small comet Hartley-2 in 2010 - to watch their disintegration stage. There are also other suspected candidates for disintegration in the vast family of comet nuclei and other Solar System bodies.

  5. Physics of comets

    CERN Document Server

    Krishna Swamy, K S

    1997-01-01

    The study of Comet Halley in 1986 was a tremendous success for cometary science. In March of that year, six spacecrafts passed through Comet Halley as close as 600 km from the nucleus and made the in situ measurements of various kinds. These space missions to Comet Halley and that of the ICE spacecraft to Comet Giacobini-Zinner combined with studies, both ground-based and above the atmosphere, have increased our knowledge of cometary science in a dramatic way.This new edition of Physics of Comets incorporates these new and exciting findings. The emphasis of the book is on the physical processe

  6. Visually observing comets

    CERN Document Server

    Seargent, David A J

    2017-01-01

    In these days of computers and CCD cameras, visual comet observers can still contribute scientifically useful data with the help of this handy reference for use in the field. Comets are one of the principal areas for productive pro-amateur collaboration in astronomy, but finding comets requires a different approach than the observing of more predictable targets. Principally directed toward amateur astronomers who prefer visual observing or who are interested in discovering a new comet or visually monitoring the behavior of known comets, it includes all the advice needed to thrive as a comet observer. After presenting a brief overview of the nature of comets and how we came to the modern understanding of comets, this book details the various types of observations that can usefully be carried out at the eyepiece of a telescope. Subjects range from how to search for new comets to visually estimating the brightness of comets and the length and orientation of tails, in addition to what to look for in comet heads a...

  7. Spectrophotometric study of five bright meteors

    International Nuclear Information System (INIS)

    Saidov, K.Kh.; Zolowa, O.F.

    1971-01-01

    The results of 200 spectrophotometric study of five bright meteors and indentification of spectral lines are given. Distribution of energy for different points of the paths of meteors is found. Masses of meteor particles are determined on the base of integrated curves of brightness

  8. Asteroid/meteorite streams

    Science.gov (United States)

    Drummond, J.

    The independent discovery of the same three streams (named alpha, beta, and gamma) among 139 Earth approaching asteroids and among 89 meteorite producing fireballs presents the possibility of matching specific meteorites to specific asteroids, or at least to asteroids in the same stream and, therefore, presumably of the same composition. Although perhaps of limited practical value, the three meteorites with known orbits are all ordinary chondrites. To identify, in general, the taxonomic type of the parent asteroid, however, would be of great scientific interest since these most abundant meteorite types cannot be unambiguously spectrally matched to an asteroid type. The H5 Pribram meteorite and asteroid 4486 (unclassified) are not part of a stream, but travel in fairly similar orbits. The LL5 Innisfree meteorite is orbitally similar to asteroid 1989DA (unclassified), and both are members of a fourth stream (delta) defined by five meteorite-dropping fireballs and this one asteroid. The H5 Lost City meteorite is orbitally similar to 1980AA (S type), which is a member of stream gamma defined by four asteroids and four fireballs. Another asteroid in this stream is classified as an S type, another is QU, and the fourth is unclassified. This stream suggests that ordinary chondrites should be associated with S (and/or Q) asteroids. Two of the known four V type asteroids belong to another stream, beta, defined by five asteroids and four meteorite-dropping (but unrecovered) fireballs, making it the most probable source of the eucrites. The final stream, alpha, defined by five asteroids and three fireballs is of unknown composition since no meteorites have been recovered and only one asteroid has an ambiguous classification of QRS. If this stream, or any other as yet undiscovered ones, were found to be composed of a more practical material (e.g., water or metalrich), then recovery of the associated meteorites would provide an opportunity for in-hand analysis of a potential

  9. 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.

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

    Science.gov (United States)

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

    2010-10-01

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

  11. Trojan Asteroid Lightcurves: Probing Internal Structure and the Origins

    Science.gov (United States)

    Ryan, E. L.

    2017-12-01

    Studies of the small bodies of the solar system reveal important clues about the condensation and formation of planetesimal bodies, and ultimately planets in planetary systems. Dynamics of small bodies have been utilized to model giant planet migration within our solar system, colors have been used to explore compositional gradients within the protoplanetary disk, & studies of the size-frequency distribution of main belt asteroids may reveal compositional dependences on planetesimal strength limiting models of planetary growth from collisional aggregration. Studies of the optical lightcurves of asteroids also yield important information on shape and potential binarity of asteroidal bodies. The K2 mission has allowed for the unprecedented collection of Trojan asteroid lightcurves on a 30 minute cadence for baselines of 10 days, in both the L4 and L5 Trojan clouds. Preliminary results from the K2 mission suggest that Trojan asteroids have bulk densities of 1 g/cc and a binary fraction ≤ 33 percent (Ryan et al., 2017, Astronomical Journal, 153, 116), however Trojan lightcurve data is actively being collected via the continued K2 mission. We will present updated results of bulk density and binary fraction of the Trojan asteroids and compare these results to other small body populations, including Hilda asteroids, transNeptunian objects and comet nuclei to test dynamical models of the origins of these populations.

  12. Catalogue of representative meteor spectra

    Czech Academy of Sciences Publication Activity Database

    Vojáček, Vlastimil; Borovička, Jiří; Koten, Pavel; Spurný, Pavel; Štork, Rostislav

    2015-01-01

    Roč. 580, August (2015), A67/1-A67/31 ISSN 0004-6361 R&D Projects: GA ČR(CZ) GAP209/11/1382 Institutional support: RVO:67985815 Keywords : meteorites * meteors * meteoroids Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 4.378, year: 2014

  13. Meteors Without Borders: a global campaign

    Science.gov (United States)

    Heenatigala, T.

    2012-01-01

    "Meteors Without Borders" is a global project, organized by Astronomers Without Borders and launched during the Global Astronomy Month in 2010 for the Lyrid meteor shower. The project focused on encouraging amateur astronomy groups to hold public outreach events for major meteor showers, conduct meteor-related classroom activities, photography, poetry and art work. It also uses social-media platforms to connect groups around the world to share their observations and photography, live during the events. At the International Meteor Conference 2011, the progress of the project was presented along with an extended invitation for collaborations for further improvements of the project.

  14. Determination of the Meteor Limiting Magnitude

    Science.gov (United States)

    Kingery, A.; Blaauw, R.; Cooke, W. J.

    2016-01-01

    The limiting meteor magnitude of a meteor camera system will depend on the camera hardware and software, sky conditions, and the location of the meteor radiant. Some of these factors are constants for a given meteor camera system, but many change between meteor shower or sporadic source and on both long and short timescales. Since the limiting meteor magnitude ultimately gets used to calculate the limiting meteor mass for a given data set, it is important to have an understanding of these factors and to monitor how they change throughout the night, as a 0.5 magnitude uncertainty in limiting magnitude translates to a uncertainty in limiting mass by a factor of two.

  15. Ammonia abundances in comets

    Science.gov (United States)

    Wyckoff, S.; Tegler, S.; Engel, L.

    The emission band strengths of the NH2 bands of Comets Halley, Hartley-Good, Thiele, and Borrelly were measured to determine the NH2 column densities for the comets. Production rates obtained using the Haser and vectorial models are in agreement within the observational errors, suggesting that a simple two-step decay model may be used to approximate the NH2 distribution in a comet's coma. Ammonia-to-water abundance ratios from 0.01 to 0.4 percent were found for the four comets. The ratio in Comet Halley is found to be Q(NH3)/Q(H2O) = 0.002 + or - 0.001. No significant difference in the ammonia abundance was found before or after perihelion in Comet Halley.

  16. The proximities of asteroids and critical points of the distance function

    Directory of Open Access Journals (Sweden)

    Milisavljević Slaviša

    2010-01-01

    Full Text Available The proximities are important for different purposes, for example to evaluate the risk of collisions of asteroids or comets with the Solar-System planets. We describe a simple and efficient method for finding the asteroid proximities in the case of elliptical orbits with a common focus. In several examples we have compared our method with the recent excellent algebraic and polynomial solutions of Gronchi (2002, 2005.

  17. Hydrogen emission in meteors as a potential marker for the exogenous delivery of organics and water

    Science.gov (United States)

    Jenniskens, Peter; Mandell, Avram M.

    2004-01-01

    We detected hydrogen Balmer-alpha (H(alpha)) emission in the spectra of bright meteors and investigated its potential use as a tracer for exogenous delivery of organic matter. We found that it is critical to observe the meteors with high enough spatial resolution to distinguish the 656.46 nm H(alpha) emission from the 657.46 nm intercombination line of neutral calcium, which was bright in the meteor afterglow. The H(alpha) line peak stayed in constant ratio to the atmospheric emissions of nitrogen during descent of the meteoroid. If all of the hydrogen originates in the Earth's atmosphere, the hydrogen atoms are expected to have been excited at T = 4400 K. In that case, we measured an H(2)O abundance in excess of 150 +/- 20 ppm at 80-90 km altitude (assuming local thermodynamic equilibrium in the air plasma). This compares with an expected water bound in meteoroid minerals) could have caused the observed H(alpha) emission, but only if the line is excited in a hot T approximately 10000 K plasma component that is unique to meteoric ablation vapor emissions such as Si(+). Assuming that the Si(+) lines of the Leonid spectrum would need the same hot excitation conditions, and a typical [H]/[C] = 1 in cometary refractory organics, we calculated an abundance ratio [C]/[Si] = 3.9 +/- 1.4 for the dust of comet 55P/Tempel-Tuttle. This range agreed with the value of [C]/[Si] = 4.4 measured for comet 1P/Halley dust. Unless there is 10 times more water vapor in the upper atmosphere than expected, we conclude that a significant fraction of the hydrogen atoms in the observed meteor plasma originated in the meteoroid.

  18. Special Report: Chemistry of Comets.

    Science.gov (United States)

    A'Hearn, Michael F.

    1984-01-01

    Discusses the chemistry of comets. How comets provide clues to the birth of the solar system, photolytic reactions on comets involving water, chemical modeling, nuclear chemistry, and research findings are among the areas considered. (JN)

  19. 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)

  20. Improving the Detection of Near-Earth Asteroids

    Science.gov (United States)

    1992-12-01

    looking. Thirty or forty years ago, stories in pulp magazines featured frontier life on dry, canal- networked Mars and swampy Venus. But in the last decade...reasons. Scientists see in asteroids a wealth of information about how the solar system formed, about compositions of planets and planetoids , comets...certain aspects of its observable features in much the same way as the stellar classification system denotes a yellow star as type G. Unfortunately, the

  1. Update on an Interstellar Asteroid

    Science.gov (United States)

    Kohler, Susanna

    2018-01-01

    Whats the news coming from the research world on the interstellar asteroid visitor, asteroid 1I/Oumuamua? Read on for an update from a few of the latest studies.What is Oumuamua?In lateOctober2017, the discovery of minor planet 1I/Oumuamua was announced. This body which researchers first labeled asa comet and later revised to an asteroid had just zipped around the Sun and was already in the process of speeding away whenwe trained our telescopes on it. Its trajectory, however, marked it as being a visitor from outside our solar system: the first knownvisitorof its kind.Since Oumuamuasdiscovery, scientists have been gathering as many observations of this bodyas possible before it vanishes into the distance. Simultaneously, theorists have leapt at the opportunity to explain its presence and the implications its passage has on our understanding of our surroundings. Here we present just a few of the latest studies that have been published on this first detected interstellar asteroid including several timelystudies published in our new journal, Research Notes of the AAS.The galactic velocity of Oumuamua does not coincide with any of the nearest stars to us. [Mamajek 2018]Where Did Oumuamua Come From?Are we sure Oumuamua didnt originate in our solar system andget scattered into a weird orbit? Jason Wright (The Pennsylvania State University) demonstrates via a series of calculations that no known solar system body could have scattered Oumuamua onto its current orbit nor could any stillunknown object bound to our solar system.Eric Mamajek (Caltech and University of Rochester) showsthat thekinematics of Oumuamua areconsistent with what we might expect of interstellar field objects, though he argues that its kinematics suggest its unlikely to have originated from many of the neareststellar systems.What AreOumuamuas Properties?Oumuamuas light curve. [Bannister et al. 2017]A team of University of Maryland scientists led by Matthew Knight captured a light curve of Oumuamua using

  2. Comet 169P/NEAT(=2002EX12): More Dead Than Alive

    Science.gov (United States)

    Kasuga, T.; Balam, D. D.; Wiegert, P. A.

    2011-10-01

    The Jupiter family comet 169P/NEAT (previously known as asteroid 2002 EX12) has a dynamical association with the ?-Capriconid meteoroid stream. In this paper, we present photometric observations of comet 169P/NEAT to further investigate the physical characters of its disintegration state related to the stream. The comet shows a point-like surface brightness profile limiting contamination due to coma emission at ˜ 4% at most, indicating no evidence of outgassing. An upper limit on the fraction of the surface that could be sublimating water ice of disintegration of the parent at every return.

  3. EXTINCTION OF SPECIES BY PERIODIC COMET SHOWERS

    Energy Technology Data Exchange (ETDEWEB)

    Davis, M.; Hut, P.; Muller, R.A.

    1984-01-01

    A 26-Myr periodicity has recently been seen in the fossil record of extinction in the geological past. At least two of these extinctions are known to be associated with the impact on the Earth of a comet or asteroid with a diameter of a few kilometres. We propose that the periodic events are triggered by an unseen companion to the Sun, travelling in a moderately eccentric orbit, which at its closest approach (perihelion) passes through the 'Oort cloud' of comets which surrounds the Sun. During each passage this unseen solar companion perturbs the orbits of these comets, sending a large number of them (over 1 x 10{sup 9}) into paths which reach the inner Solar System. Several of these hit the Earth, on average, in the following million years. At present the unseen companion should be approximately at its maximum distance from the Sun, {approx}2.4 light yr, and it will present no danger to the Earth until approximately AD 15,000,000.

  4. Network of Nano-Landers for In-Situ Characterization of Asteroid Impact Studies

    OpenAIRE

    Kalita, Himangshu; Asphaug, Erik; Schwartz, Stephen; Thangavelautham, Jekanthan

    2017-01-01

    Exploration of asteroids and comets can give insight into the origins of the solar system and can be instrumental in planetary defence and in-situ resource utilization (ISRU). Asteroids, due to their low gravity are a challenging target for surface exploration. Current missions envision performing touch-and-go operations over an asteroid surface. In this work, we analyse the feasibility of sending scores of nano-landers, each 1 kg in mass and volume of 1U, or 1000 cm3. These landers would hop...

  5. PHYS: Division of Physical Chemistry 258 - Properties and Origins of Cometary and Asteroidal Organic Matter Delivered to the Early Earth

    Science.gov (United States)

    Messenger, Scott; Nguyen, Ann

    2017-01-01

    Comets and asteroids may have contributed much of the Earth's water and organic matter. The Earth accretes approximately 4x10(exp 7) Kg of dust and meteorites from these sources every year. The least altered meteorites contain complex assemblages of organic compounds and abundant hydrated minerals. These carbonaceous chondrite meteorites probably derive from asteroids that underwent hydrothermal processing within the first few million years after their accretion. Meteorite organics show isotopic and chemical signatures of low-T ion-molecule and grain-surface chemistry and photolysis of icy grains that occurred in cold molecular clouds and the outer protoplanetary disk. These signatures have been overprinted by aqueously mediated chemistry in asteroid parent bodies, forming amino acids and other prebiotic molecules. Comets are much richer in organic matter but it is less well characterized. Comet dust collected in the stratosphere shows larger H and N isotopic anomalies than most meteorites, suggesting better preservation of primordial organics. Rosetta studies of comet 67P coma dust find complex organic matter that may be related to the macromolecular material that dominates the organic inventory of primitive meteorites. The exogenous organic material accreting on Earth throughout its history is made up of thousands of molecular species formed in diverse processes ranging from circumstellar outflows to chemistry at near absolute zero in dark cloud cores and the formative environment within minor planets. NASA and JAXA are currently flying sample return missions to primitive, potentially organic-rich asteroids. The OSIRIS-REx and Hayabusa2 missions will map their target asteroids, Bennu and Ryugu, in detail and return regolith samples to Earth. Laboratory analyses of these pristine asteroid samples will provide unprecedented views of asteroidal organic matter relatively free of terrestrial contamination within well determined geological context. Studies of

  6. Radar meteor rates and atmospheric density changes

    International Nuclear Information System (INIS)

    Ellyett, C.D.; Kennewell, J.A.

    1980-01-01

    It has been suggested that variations of the atmospheric scale height at meteor ablation altitudes could be responsible for the recorded correlations between radar meteor rates and solar activity. A quantitative examination of a theoretical treatment by Kaiser (personal communication) is reported which shows that his suggestion is certainly plausible and gives details of the necessary scale height changes as a function of the meteor mass exponent. (U.K.)

  7. New radio meteor detecting and logging software

    Science.gov (United States)

    Kaufmann, Wolfgang

    2017-08-01

    A new piece of software ``Meteor Logger'' for the radio observation of meteors is described. It analyses an incoming audio stream in the frequency domain to detect a radio meteor signal on the basis of its signature, instead of applying an amplitude threshold. For that reason the distribution of the three frequencies with the highest spectral power are considered over the time (3f method). An auto notch algorithm is developed to prevent the radio meteor signal detection from being jammed by a present interference line. The results of an exemplary logging session are discussed.

  8. Asteroids mass determination

    International Nuclear Information System (INIS)

    Hoffmann, M.

    1989-01-01

    Basic methods for asteroid mass determinations and their errors are discussed. New results and some current developments in the astrometric method are reviewed. New methods and techniques, such as electronic imaging, radar ranging and space probes are becoming important for asteroid mass determinations. Mass and density estimations on rotational properties and possible satelites are also discussed

  9. Impacts of asteroidal material on cometary nuclei

    Science.gov (United States)

    Solc, M.; Stork, R.; Kozel, M.

    1994-07-01

    Impacts can bring geologically evolved asteroidal dust or lumps into cometary nuclei that consist of more primitive material. We estimate the amount of the asteroidal material captured in nucleus of some short-period comets during one revolution, during the whole lifetime of the nucleus in the inner solar system, and, finally, during the period shortly after the formation of nucleus in outer regions of the protoplanetary disk. Interplanetary dust grains registered by Galileo and Ulysses dust detectors between Venus and Jupiter together with IRAS photometry of dust in asteroidal band provided us with the basic data for estimating the dust concentration in space at various places not far from the ecliptic. Another basis was the five populations of interplanetary meteoroids proposed by Divine and the paper on influx of interplanetary bodies onto Earth compiled by Ceplecha. We attempted to model a cratering story of a typical cometary nucleus during its lifetime starting from its formation. According to numerical models of impacts into ice, the penetration depth varies from millimeters to several tens of meters. Models were computed for the size range of projectiles from 10 micron to 10 m, velocities from 10 m/s to 10 km/s, and densities from 1 to 8 g/ccm.

  10. Realm of the comets

    International Nuclear Information System (INIS)

    Weissman, P.R.

    1987-01-01

    Studies of Jovian perturbations of the orbits of long-period comets led to the concept of the Oort cloud of 180 billion comets at 50,000-150,000 AU from the sun. Several comets are induced to move toward the sun every million years by the passage of a star at a distance of a few light years. The location of the cloud has since been revised to 20,000-100,000 AU, and comets are now accepted as remnant material fron the proto-solar system epoch. The galactic disk and random, close-passing stars may also cause rare, large perturbations in the orbits of the cloud comets, sending large numbers of comets through the inner solar system. The resulting cometary storm is a candidate cause for the wholesale extinction of dinosaurs in the Cretaceous-Terniary transition due to large number of planetesimals, or one large comet, striking the earth, in a short period of time. The IRAS instruments have detected similar clouds of material around other stars

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

    NARCIS (Netherlands)

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

    2016-01-01

    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

  12. Comets in UV

    Science.gov (United States)

    Shustov, B.; Sachkov, M.; Gómez de Castro, A. I.; Vallejo, J. C.; Kanev, E.; Dorofeeva, V.

    2018-04-01

    Comets are important "eyewitnesses" of Solar System formation and evolution. Important tests to determine the chemical composition and to study the physical processes in cometary nuclei and coma need data in the UV range of the electromagnetic spectrum. Comprehensive and complete studies require additional ground-based observations and in situ experiments. We briefly review observations of comets in the ultraviolet (UV) and discuss the prospects of UV observations of comets and exocomets with space-borne instruments. A special reference is made to the World Space Observatory-Ultraviolet (WSO-UV) project.

  13. Comets: looking ahead.

    Science.gov (United States)

    A'Hearn, Michael F

    2017-07-13

    We outline the key questions about comets that must be answered in order to understand cometary formation in the context of the protoplanetary disc and the role of comets in the formation and evolution of the solar system. We then discuss the new understanding of comets from Rosetta and from other recent advances, including work presented by others at the discussion meeting. Finally, we suggest some key directions for future projects to better address the above questions.This article is part of the themed issue 'Cometary science after Rosetta'. © 2017 The Author(s).

  14. Properties of the moon, Mars, Martian satellites, and near-earth asteroids

    Science.gov (United States)

    Taylor, Jeffrey G.

    Environments and surface properties of the moon, Mars, Martian satellites, and near-earth asteroids are discussed. Topics include gravity, atmospheres, surface properties, surface compositions, seismicity, radiation environment, degradation, use of robotics, and environmental impacts. Gravity fields vary from large fractions of the earth's field such as 1/3 on Mars and 1/6 on the moon to smaller fractions of 0.0004 g on an asteroid 1 km in diameter. Spectral data and the analogy with meteor compositions suggest that near-earth asteroids may contain many resources such as water-rich carbonaceous materials and iron-rich metallic bodies. It is concluded that future mining and materials processing operations from extraterrestrial bodies require an investment now in both (1) missions to the moon, Mars, Phobos, Deimos, and near-earth asteroids and (2) earth-based laboratory research in materials and processing.

  15. Radar meteors range distribution model. I. Theory

    Czech Academy of Sciences Publication Activity Database

    Pecinová, Drahomíra; Pecina, Petr

    2007-01-01

    Roč. 37, č. 2 (2007), s. 83-106 ISSN 1335-1842 R&D Projects: GA ČR GA205/03/1405 Institutional research plan: CEZ:AV0Z10030501 Keywords : physics of meteors * radar meteors * range distribution Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics

  16. Global variation of meteor trail plasma turbulence

    Directory of Open Access Journals (Sweden)

    L. P. Dyrud

    2011-12-01

    Full Text Available We present the first global simulations on the occurrence of meteor trail plasma irregularities. These results seek to answer the following questions: when a meteoroid disintegrates in the atmosphere, will the resulting trail become plasma turbulent? What are the factors influencing the development of turbulence? and how do these trails vary on a global scale? Understanding meteor trail plasma turbulence is important because turbulent meteor trails are visible as non-specular trails to coherent radars. Turbulence also influences the evolution of specular radar meteor trails; this fact is important for the inference of mesospheric temperatures from the trail diffusion rates, and their usage for meteor burst communication. We provide evidence of the significant effect that neutral atmospheric winds and ionospheric plasma density have on the variability of meteor trail evolution and on the observation of non-specular meteor trails. We demonstrate that trails are far less likely to become and remain turbulent in daylight, explaining several observational trends for non-specular and specular meteor trails.

  17. System for accurate ranging of meteor trails

    International Nuclear Information System (INIS)

    Tshebotaryov, R.P.; Sidorin, V.N.

    1970-01-01

    The necessity of precise ranging of meteor trails is emphasised possible methods are considered. A scheme with a non ius circular trace and intensity indication giving an unique for meteor radar accuracy ± 50 m is described in detail. Results are given of experimental and practical work of the system

  18. William Herschel and Comets

    Science.gov (United States)

    Sullivan, Woodruff

    2018-01-01

    I examine the observational and theoretical researches of William Herschel on 21 comets that he observed over the period 1781 to 1812. Herschel's focus, unlike most contemporaries, was on their physical structure, not their orbits. He forged a strong connection between comets and his nebulae with a scheme of cometary "maturation" (1812) involved a comet traveling from star to star after its central "planetary body'; was born from gravitational collapse of a nebula. During close passages of a star, the comet brightened and lost mass from its atmosphere; at other times, when between stars, it encountered nebulae and was rejuvenated by picking up more mass. Laplace soon adopted these ideas to improve his nebula hypothesis for solar system formation.

  19. Asteroid clusters similar to asteroid pairs

    Science.gov (United States)

    Pravec, P.; Fatka, P.; Vokrouhlický, D.; Scheeres, D. J.; Kušnirák, P.; Hornoch, K.; Galád, A.; Vraštil, J.; Pray, D. P.; Krugly, Yu. N.; Gaftonyuk, N. M.; Inasaridze, R. Ya.; Ayvazian, V. R.; Kvaratskhelia, O. I.; Zhuzhunadze, V. T.; Husárik, M.; Cooney, W. R.; Gross, J.; Terrell, D.; Világi, J.; Kornoš, L.; Gajdoš, Š.; Burkhonov, O.; Ehgamberdiev, Sh. A.; Donchev, Z.; Borisov, G.; Bonev, T.; Rumyantsev, V. V.; Molotov, I. E.

    2018-04-01

    We studied the membership, size ratio and rotational properties of 13 asteroid clusters consisting of between 3 and 19 known members that are on similar heliocentric orbits. By backward integrations of their orbits, we confirmed their cluster membership and estimated times elapsed since separation of the secondaries (the smaller cluster members) from the primary (i.e., cluster age) that are between 105 and a few 106 years. We ran photometric observations for all the cluster primaries and a sample of secondaries and we derived their accurate absolute magnitudes and rotation periods. We found that 11 of the 13 clusters follow the same trend of primary rotation period vs mass ratio as asteroid pairs that was revealed by Pravec et al. (2010). We generalized the model of the post-fission system for asteroid pairs by Pravec et al. (2010) to a system of N components formed by rotational fission and we found excellent agreement between the data for the 11 asteroid clusters and the prediction from the theory of their formation by rotational fission. The two exceptions are the high-mass ratio (q > 0.7) clusters of (18777) Hobson and (22280) Mandragora for which a different formation mechanism is needed. Two candidate mechanisms for formation of more than one secondary by rotational fission were published: the secondary fission process proposed by Jacobson and Scheeres (2011) and a cratering collision event onto a nearly critically rotating primary proposed by Vokrouhlický et al. (2017). It will have to be revealed from future studies which of the clusters were formed by one or the other process. To that point, we found certain further interesting properties and features of the asteroid clusters that place constraints on the theories of their formation, among them the most intriguing being the possibility of a cascade disruption for some of the clusters.

  20. A fragment-cloud model for asteroid breakup and atmospheric energy deposition

    Science.gov (United States)

    Wheeler, Lorien F.; Register, Paul J.; Mathias, Donovan L.

    2017-10-01

    As asteroids break up during atmospheric entry, they deposit energy that can be seen in flares of light and, if substantial enough, can produce damaging blast waves. Analytic models of asteroid breakup and energy deposition processes are needed in order to assess potential airburst hazards, and to enable inferences about asteroid properties or breakup physics to be made from comparisons with observed meteors. This paper presents a fragment-cloud model (FCM) that is able to represent a broad range of breakup behaviors and the resulting variations in energy deposition in ways that make it a useful tool for both applications. Sensitivity studies are performed to investigate how variations the model's fragmentation parameters affect the energy deposition results for asteroids 20-500 m in diameter. The model is also used to match observational data from the Chelyabinsk meteor and infer potential asteroid properties and representative modeling parameter ranges. Results illustrate how the model's fragmentation parameters can introduce different energy deposition features, and how much they affect the overall energy deposition rates, magnitudes, and altitudes that would drive ground damage for risk assessment applications.

  1. Mineralogy of Interplanetary Dust Particles from the Comet Giacobini-Zinner Dust Stream Collections

    Science.gov (United States)

    Nakamura-Messenger, K.; Messenger, S.; Westphal, A. J.; Palma, R. L.

    2015-01-01

    The Draconoid meteor shower, originating from comet 21P/Giacobini-Zinner, is a low-velocity Earth-crossing dust stream that had a peak anticipated flux on Oct. 8, 2012. In response to this prediction, NASA performed dedicated stratospheric dust collections to target interplanetary dust particles (IDPs) from this comet stream on Oct 15-17, 2012 [3]. Twelve dust particles from this targeted collection were allocated to our coordinated analysis team for studies of noble gas (Univ. Minnesota, Minnesota State Univ.), SXRF and Fe-XANES (SSL Berkeley) and mineralogy/isotopes (JSC). Here we report a mineralogical study of 3 IDPs from the Draconoid collection..

  2. Thermal alteration in carbonaceous chondrites and implications for sublimation in rock comets

    Science.gov (United States)

    Springmann, Alessondra; Lauretta, Dante S.; Steckloff, Jordan K.

    2015-11-01

    Rock comets are small solar system bodies in Sun-skirting orbits (perihelion q shower, is the only rock comet currently known to periodically eject dust and form a coma. Thermal fracturing or thermal decomposition of surface materials may be driving Phaethon’s cometary activity (Li & Jewitt, 2013). Phaethon-like asteroids have dynamically unstable orbits, and their perihelia can change rapidly over their ~10 Myr lifetimes (de León et al., 2010), raising the possibility that other asteroids may have been rock comets in the past. Here, we propose using spectroscopic observations of mercury (Hg) as a tracer of an asteroid’s thermal metamorphic history, and therefore as a constraint on its minimum achieved perihelion distance.B-class asteroids such as Phaethon have an initial composition similar to aqueously altered primitive meteorites such as CI- or CM-type meteorites (Clark et al., 2010). Laboratory heating experiments of ~mm sized samples of carbonaceous chondrite meteorites from 300K to 1200K at a rate of 15K/minute show mobilization and volatilization of various labile elements at temperatures that could be reached by Mercury-crossing asteroids. Samples became rapidly depleted in labile elements and, in particular, lost ~75% of their Hg content when heated from ~500-700 K, which corresponds to heliocentric distances of ~0.15-0.3 au, consistent with our thermal models. Mercury has strong emission lines in the UV (~ 185 nm) and thus its presence (or absence) relative to carbonaceous chondrite abundances would indicate if these bodies had perihelia in their dynamical histories inside of 0.15 AU, and therefore may have previously been Phaethon-like rock comets. Future space telescopes or balloon-borne observing platforms equipped with a UV spectrometer could potentially detect the presence or absence of strong ultraviolet mercury lines on rock comets or rock comet candidates.

  3. Near Earth Asteroid Scout

    Data.gov (United States)

    National Aeronautics and Space Administration — Near-Earth Asteroid Scout, or NEA Scout, is a 6U CubeSat developed jointly between NASA’s Marshall Space Flight Center and the Jet Propulsion Laboratory. NASA...

  4. Asteroid rotation. IV

    International Nuclear Information System (INIS)

    Harris, A.W.; Young, J.W.

    1983-01-01

    The results from the year 1979 of an ongoing program of asteroid photometry at Table Mountain Observatory are presented. The results for 53 asteroids are summarized in a table, showing the number, name, opposition date, taxonomic class, diameter, absolute magnitude, mean absolute magnitude at zero phase angle and values of the absolute magnitude and linear phase coefficient derived from it, the rotation period in hours, peak-to-peak amplitude of variation, difference between mean and maximum brightness, and reliability index. Another table presents data on aspect and comparison stars, including brightness and distance data. Reliable rotation periods are reported for 22 asteroids for which no previous values are known. For seven asteroids, periods are reported which are revisions of previously reported values

  5. UBV MEAN ASTEROID COLORS

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set is a compilation of mean U-B and B-V color indices of asteroids, collected from the published literature and from the unpublished Lowell Observatory...

  6. 24-COLOR ASTEROID SURVEY

    Data.gov (United States)

    National Aeronautics and Space Administration — This dataset is comprised of asteroid flux data measured in 26 filters using the McCord dual beam photometer, and covering the range 0.32 - 1.08 microns for 285...

  7. SAWYER ASTEROID SPECTRA

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set contains 94 optical asteroid spectra obtained by Scott Sawyer as part of his Ph.D. dissertation at the University of Texas at Austin. Observational...

  8. 52-COLOR ASTEROID SURVEY

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set contains 52-color IR data of asteroids, taken using a double circularly variable filter. The short wavelength portion of the CVF covered the octave...

  9. A retrograde co-orbital asteroid of Jupiter.

    Science.gov (United States)

    Wiegert, Paul; Connors, Martin; Veillet, Christian

    2017-03-29

    Recent theoretical work in celestial mechanics has revealed that an asteroid may orbit stably in the same region as a planet, despite revolving around the Sun in the sense opposite to that of the planet itself. Asteroid 2015 BZ 509 was discovered in 2015, but with too much uncertainty in its measured orbit to establish whether it was such a retrograde co-orbital body. Here we report observations and analysis that demonstrates that asteroid 2015 BZ 509 is indeed a retrograde co-orbital asteroid of the planet Jupiter. We find that 2015 BZ 509 has long-term stability, having been in its current, resonant state for around a million years. This is long enough to preclude precise calculation of the time or mechanism of its injection to its present state, but it may be a Halley-family comet that entered the resonance through an interaction with Saturn. Retrograde co-orbital asteroids of Jupiter and other planets may be more common than previously expected.

  10. PRODUCTION OF NEAR-EARTH ASTEROIDS ON RETROGRADE ORBITS

    International Nuclear Information System (INIS)

    Greenstreet, S.; Gladman, B.; Ngo, H.; Granvik, M.; Larson, S.

    2012-01-01

    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 ∼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 ∼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.

  11. Comet LINEAR C/1999 S4 - an absolutely well-behaved comet before breakup

    Science.gov (United States)

    Peschke, S. B.; Lisse, C. M.; Fernandez, Y. R.; Ressler, M.; Stickel, M.; Kaminski, C.; Golish, B.

    2000-10-01

    We present results from infrared imaging of comet LINEAR C/1999 S4 on June 17 - 19, 2000 (pre-breakup), using the near-IR camera NSFCAM and the mid-IR camera MIRLIN at the 3m NASA/IRTF. Images and multi-wavelength spectroscopy were obtained in the zJHK'L'MNQ bands, and were used to create a 1.0 - 25 μ m SED of the comet's dust and nucleus. The coma's contribution at each wavelength was modeled using spatial fitting (Fernandez 1999, PhD thesis; Lisse et al. 1999, Icarus 140, 189). The resulting comatic and nuclear SEDs were then modeled using modified Mie theory (Lisse et al. 1998, ApJ 496, 971) and the standard nuclear thermal models (Lebofsky and Spencer 1989, Asteroids II, 128), respectively. We report the resulting dust PSD, mass loss rate, and albedo, as well as the nuclear radius, and we compare these results to those obtained by others from optical data both before and after the comet's breakup in late July 2000.

  12. Comets in Australian Aboriginal Astronomy

    Science.gov (United States)

    Hamacher, Duane W.; Norris, Ray P.

    2011-03-01

    We present 25 accounts of comets from 40 Australian Aboriginal communities, citing both supernatural perceptions of comets and historical accounts of historically bright comets. Historical and ethnographic descriptions include the Great Comets of 1843, 1861, 1901, 1910, and 1927. We describe the perceptions of comets in Aboriginal societies and show that they are typically associated with fear, death, omens, malevolent spirits, and evil magic, consistent with many cultures around the world. We also provide a list of words for comets in 16 different Aboriginal languages.

  13. PROBLEM OF LATENT MASS UNDER RADIATION OF METEORS

    OpenAIRE

    Smirnov, V. A.

    2017-01-01

    The date on absolute spectrophotometry of meteor spectrograms permit to estimate the number of radiating particles for different brightness of meteor. Methods of nonradiation meteor mass estimation are given. Comparison of observed numbers of radiating concentration with know data of artificial cosmic sample will allow to get the coefficients for calculation the nonradiating meteor mass.

  14. Jupiter Laser Facility - COMET Laser

    Data.gov (United States)

    Federal Laboratory Consortium — COMET has 4 beam configurations with uncompressed pulse lengths from 500 ps to 6 ns, compressed pulses to 0.5 ps, and beam energies up to 20 J. COMET can fire every...

  15. The KUT meteor radar: An educational low cost meteor observation system by radio forward scattering

    Science.gov (United States)

    Madkour, W.; Yamamoto, M.

    2016-01-01

    The Kochi University of Technology (KUT) meteor radar is an educational low cost observation system built at Kochi, Japan by successive graduate students since 2004. The system takes advantage of the continuous VHF- band beacon signal emitted from Fukui National College of Technology (FNCT) for scientific usage all over Japan by receiving the forward scattered signals. The system uses the classical forward scattering setup similar to the setup described by the international meteor organization (IMO), gradually developed from the most basic single antenna setup to the multi-site meteor path determination setup. The primary objective is to automate the observation of the meteor parameters continuously to provide amounts of data sufficient for statistical analysis. The developed software system automates the observation of the astronomical meteor parameters such as meteor direction, velocity and trajectory. Also, automated counting of meteor echoes and their durations are used to observe mesospheric ozone concentration by analyzing the duration distribution of different meteor showers. The meteor parameters observed and the methodology used for each are briefly summarized.

  16. Meteor shower activity derived from meteor watching public campaign in Japan

    Science.gov (United States)

    Ishizaki, Masaharu; Watanabe, Jun-ichi; Sato, Mikiya

    2017-09-01

    We have carried out a meteor watching public campaigns from 2004 for major meteor showers in the case of appropriate observing condition as one of the outreach programs conducted by National Astronomical Observatory of Japan. We received a huge number of the reports on meteor counts from the general public participants. The results sometimes show similar time variation of the hourly rates derived from the data collected by skilled observers. In this paper, some of the results are presented showing that such campaigns have a potential to extract scientific result related to the meteor showers mainly due to the large number of the data collected by unskilled observers.

  17. Orbital Alignment of Main-belt Comets

    Science.gov (United States)

    Kim, Yoonyoung; JeongAhn, Youngmin; Hsieh, Henry H.

    2018-03-01

    We examine the orbital element distribution of main-belt comets (MBCs), which are objects that exhibit cometary activity yet orbit in the main asteroid belt and may be potentially useful as tracers of ice in the inner solar system. We find that the currently known and currently active MBCs have remarkably similar longitudes of perihelion, which are also aligned with that of Jupiter. The clustered objects have significantly higher current osculating eccentricities relative to their proper eccentricities, consistent with their orbits being currently, though only temporarily, secularly excited in osculating eccentricity due to Jupiter’s influence. At the moment, most MBCs seem to have current osculating elements that may be particularly favorable for the object becoming active (e.g., maybe because of higher perihelion temperatures or higher impact velocities causing an effective increase in the size of the potential triggering impactor population). At other times, other icy asteroids will have those favorable conditions and might become MBCs at those times as well.

  18. Comet 169P/NEAT(=2002 EX12): The Parent Body of the α-Capricornid Meteoroid Stream

    Science.gov (United States)

    Kasuga, Toshihiro; Balam, David D.; Wiegert, Paul A.

    2010-12-01

    The Jupiter-family comet 169P/NEAT (previously known as asteroid 2002 EX12) has a dynamical association with the α-Capricornid meteoroid stream. In this paper, we present photometric observations of comet 169P/NEAT to further investigate the physical characters of its disintegration state related to the stream. The comet shows a point-like surface brightness profile limiting contamination due to coma emission to ~4% at most, indicating no evidence of outgassing. An upper limit on the fraction of the surface that could be sublimating water ice of disintegration of the parent at every return.

  19. Meteor Shower Forecasting for Spacecraft Operations

    Science.gov (United States)

    Moorhead, Althea V.; Cooke, William J.; Campbell-Brown, Margaret D.

    2017-01-01

    Although sporadic meteoroids are a much greater hazard to spacecraft than shower meteoroids in general, meteor showers can significantly increase the risk of damage over short time periods. Because showers are brief, it is sometimes possible to mitigate the risk operationally, which requires accurate predictions of shower activity. NASA's Meteoroid Environment Office generates an annual meteor shower forecast that describes the variations in the near-Earth meteoroid flux produced by meteor showers, which presents the shower flux both in absolute terms and relative to the sporadic ux. The shower forecast incorporates model predictions of annual variations in shower activity and quotes fluxes to several limiting particle kinetic energies. In this work, we describe our forecasting methods, compare them to actual observations, and highlight recent improvements to the temporal pro les based on flux measurements from the Canadian Meteor Orbit Radar (CMOR).

  20. 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

  1. Analysis of ALTAIR 1998 Meteor Radar Data

    Science.gov (United States)

    Zinn, J.; Close, S.; Colestock, P. L.; MacDonell, A.; Loveland, R.

    2011-01-01

    We describe a new analysis of a set of 32 UHF meteor radar traces recorded with the 422 MHz ALTAIR radar facility in November 1998. Emphasis is on the velocity measurements, and on inferences that can be drawn from them regarding the meteor masses and mass densities. We find that the velocity vs altitude data can be fitted as quadratic functions of the path integrals of the atmospheric densities vs distance, and deceleration rates derived from those fits all show the expected behavior of increasing with decreasing altitude. We also describe a computer model of the coupled processes of collisional heating, radiative cooling, evaporative cooling and ablation, and deceleration - for meteors composed of defined mixtures of mineral constituents. For each of the cases in the data set we ran the model starting with the measured initial velocity and trajectory inclination, and with various trial values of the quantity mPs 2 (the initial mass times the mass density squared), and then compared the computed deceleration vs altitude curves vs the measured ones. In this way we arrived at the best-fit values of the mPs 2 for each of the measured meteor traces. Then further, assuming various trial values of the density Ps, we compared the computed mass vs altitude curves with similar curves for the same set of meteors determined previously from the measured radar cross sections and an electrostatic scattering model. In this way we arrived at estimates of the best-fit mass densities Ps for each of the cases. Keywords meteor ALTAIR radar analysis 1 Introduction This paper describes a new analysis of a set of 422 MHz meteor scatter radar data recorded with the ALTAIR High-Power-Large-Aperture radar facility at Kwajalein Atoll on 18 November 1998. The exceptional accuracy/precision of the ALTAIR tracking data allow us to determine quite accurate meteor trajectories, velocities and deceleration rates. The measurements and velocity/deceleration data analysis are described in Sections

  2. The Maria asteroid family

    Science.gov (United States)

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

    2017-11-01

    The Maria asteroid family is a group of S-type asteroids. Its location adjacent to the left side of the 3J:-1A mean-motion resonances could be the reason for the absence of the left side of the `V' shape in the (a, 1/D) domain. This family can be considered as a likely source of ordinary chondrite-like material. In this work, we make use of the time dependence of the asymmetric coefficient AS describing the degree of asymmetry of the C distribution of a fictitious Maria family generated with the value of the ejection velocity parameter VEJ = 35 m s-1 to obtain an age estimate of 1750_{+537}^{-231} Myr, in good agreement with the family age found in the literature. Analysing the contribution to the near-Earth object (NEO) population, we found that about 7.6 per cent of presently known near-Earth asteroids (NEAs) have orbits similar to asteroids from the Maria family. Only ˜1.7 per cent of our simulated family can stay in NEO space for more than 10 Myr, while only five asteroids become NEOs in the last 500 Myr of the simulation.

  3. Some features of evolution of meteor streams

    International Nuclear Information System (INIS)

    Babadzhanov, P.B.; Obrubov, Y.V.

    1983-01-01

    It is shown that a number of features of meteor showers such as the correlation of orbital semimajor axes and longitudes of the ascending nodes with meteor magnitudes, the restriction of visibility periods and the displacement of maximum activity dates is explained by the joint influence of planetary perturbations, the Poynting-Robertson effect and its corpuscular analogue, light pressure and ejection velocities of different mass meteoroids from cometary nuclei. (orig.)

  4. Discovering the Nature of Comets.

    Science.gov (United States)

    Whipple, Fred L.

    1986-01-01

    "The Mystery of Comets" by Dr. Fred Whipple provides an introduction to the modern picture of comets and his personal reminiscences of how his model of comets came to be. An adaptation of several sections of the book is presented. (JN)

  5. Term Projects on Interstellar Comets

    Science.gov (United States)

    Mack, John E.

    1975-01-01

    Presents two calculations of the probability of detection of an interstellar comet, under the hypothesis that such comets would escape from comet clouds similar to that believed to surround the sun. Proposes three problems, each of which would be a reasonable term project for a motivated undergraduate. (Author/MLH)

  6. 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...

  7. Asteroids astronomical and geological bodies

    CERN Document Server

    Burbine, Thomas H

    2016-01-01

    Asteroid science is a fundamental topic in planetary science and is key to furthering our understanding of planetary formation and the evolution of the Solar System. Ground-based observations and missions have provided a wealth of new data in recent years, and forthcoming missions promise further exciting results. This accessible book presents a comprehensive introduction to asteroid science, summarising the astronomical and geological characteristics of asteroids. The interdisciplinary nature of asteroid science is reflected in the broad range of topics covered, including asteroid and meteorite classification, chemical and physical properties of asteroids, observational techniques, cratering, and the discovery of asteroids and how they are named. Other chapters discuss past, present and future space missions and the threat that these bodies pose for Earth. Based on an upper-level course on asteroids and meteorites taught by the author, this book is ideal for students, researchers and professional scientists ...

  8. ESA Unveils Its New Comet Chaser.

    Science.gov (United States)

    1999-07-01

    October 2007 before heading away from the Sun towards Comet Wirtanen. As it bounces around the Solar System, Rosetta will also make two excursions into the main asteroid belt, where it will obtain the first close-up images and information on two contrasting objects, 4979 Otawara and 140 Siwa. Scientists believe Otawara is less than 20 km across, whereas Siwa is probably 110 km in diameter, much larger than any asteroid which has so far been visited by spacecraft. Rosetta will fly to within 1,000 km of Otawara in July 2006, followed by a similar rendezvous with Siwa two years later. However, the most difficult phase of the mission will be the final rendezvous with the fast-moving comet (the foreseen date for the rendezvous manoeuvre is 27 November 2011, close approach is set for 20 May 2012 and orbit insertion around the nucleus is set for 28 May 2012). Thus, after a 5.3 billion km space odyssey, Rosetta will make first contact with Wirtanen about 675 million km from the Sun. At this distance, sunlight is 20 times weaker than on Earth, and the comet's nucleus will still be frozen and inactive. Once the navigation team are able to determine the comet's exact location from images returned by the spacecraft camera, a series of braking manoeuvres will allow Rosetta to match speed and direction with its target. After about seven months of edging closer, Rosetta will eventually close to within 2 km of Wirtanen's frozen nucleus. From its close orbit above the tiny nucleus, Rosetta will be able to send back the most detailed images and information ever obtained of a comet. When a suitable landing site has been chosen, about a month after global mapping starts, the orbiter will release a 100 kg lander onto the comet's solid surface. Touchdown must be quite slow - less than one metre per second - to allow for the almost negligible gravitational pull of the tiny nucleus. In order to ensure that the lander does not bounce and disappear into space, an anchoring harpoon will be fired

  9. METEOR v1.0 - User's Guide

    International Nuclear Information System (INIS)

    Palomo, E.

    1994-01-01

    This script is a User's Guide for the software package METEOR for statistical analysis of meteorological data series. The original version of METEOR have been developed by Ph.D. Elena Palomo, CIEMAT-IER, GIMASE. It is built by linking programs and routines written in FORTRAN 77 and it adds the graphical capabilities of GNUPLOT. The shape of this toolbox was designed following the criteria of modularity, flexibility and agility criteria. All the input, output and analysis options are structured in three main menus: i) the first is aimed to evaluate the quality of the data set; ii) the second is aimed for pre-processing of the data; and iii) the third is aimed towards the statistical analyses and for creating the graphical outputs. Actually the information about METEOR is constituted by three documents written in spanish: 1) METEOR v1.0: User's guide; 2) METEOR v1.0: A usage example; 3) METEOR v1.0: Design and structure of the software package. (Author)

  10. 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.

  11. Death of a comet

    CERN Multimedia

    Hawkes, N

    2000-01-01

    The comet Linear dissolved as it made its closest approach to the sun on July 25th. The first stages of its breakup had been witnessed by the Hubble telescope when it threw off a piece of its crust (3 paragraphs).

  12. Comet radar explorer

    Science.gov (United States)

    Farnham, Tony; Asphaug, Erik; Barucci, Antonella; Belton, Mike; Bockelee-Morvan, Dominique; Brownlee, Donald; Capria, Maria Teresa; Carter, Lynn; Chesley, Steve; Farnham, Tony; Gaskell, Robert; Gim, Young; Heggy, Essam; Herique, Alain; Klaasen, Ken; Kofman, Wlodek; Kreslavsky, Misha; Lisse, Casey; Orosei, Roberto; Plaut, Jeff; Scheeres, Dan

    The Comet Radar Explorer (CORE) is designed to perform a comprehensive and detailed exploration of the interior, surface, and inner coma structures of a scientifically impor-tant Jupiter family comet. These structures will be used to investigate the origins of cometary nuclei, their physical and geological evolution, and the mechanisms driving their spectacular activity. CORE is a high heritage spacecraft, injected by solar electric propulsion into orbit around a comet. It is capable of coherent deep radar imaging at decameter wavelengths, high resolution stereo color imaging, and near-IR imaging spectroscopy. Its primary objective is to obtain a high-resolution map of the interior structure of a comet nucleus at a resolution of ¿100 elements across the diameter. This structure shall be related to the surface geology and morphology, and to the structural details of the coma proximal to the nucleus. This is an ideal complement to the science from recent comet missions, providing insight into how comets work. Knowing the structure of the interior of a comet-what's inside-and how cometary activity works, is required before we can understand the requirements for a cryogenic sample return mission. But more than that, CORE is fundamental to understanding the origin of comets and their evolution in time. The mission is made feasible at low cost by the use of now-standard MARSIS-SHARAD reflec-tion radar imaging hardware and data processing, together with proven flight heritage of solar electric propulsion. Radar flight heritage has been demonstrated by the MARSIS radar on Mars Express (Picardi et al., Science 2005; Plaut et al., Science 2007), the SHARAD radar onboard the Mars Reconnaissance Orbiter (Seu et al., JGR 2007), and the LRS radar onboard Kaguya (Ono et al, EPS 2007). These instruments have discovered detailed subsurface structure to depths of several kilometers in a variety of terrains on Mars and the Moon. A reflection radar deployed in orbit about a comet

  13. Comets in Indian Scriptures

    Science.gov (United States)

    Das Gupta, P.

    2016-01-01

    The Indo-Aryans of ancient India observed stars and constellations for ascertaining auspicious times in order to conduct sacrificial rites ordained by the Vedas. Naturally, they would have sighted comets and referred to them in the Vedic texts. In Rigveda (circa 1700-1500 BC) and Atharvaveda (circa 1150 BC), there are references to dhumaketus and ketus, which stand for comets in Sanskrit. Rigveda speaks of a fig tree whose aerial roots spread out in the sky (Parpola 2010). Had this imagery been inspired by the resemblance of a comet's tail with long and linear roots of a banyan tree (ficus benghalensis)? Varahamihira (AD 550) and Ballal Sena (circa AD 1100-1200) described a large number of comets recorded by ancient seers, such as Parashara, Vriddha Garga, Narada, and Garga, to name a few. In this article, we propose that an episode in Mahabharata in which a radiant king, Nahusha, who rules the heavens and later turns into a serpent after he kicked the seer Agastya (also the star Canopus), is a mythological retelling of a cometary event.

  14. Splitting of Comets

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 7; Issue 1. Splitting of Comets. Utpal Mukhopadhyay. General Article Volume 7 Issue 1 January 2002 pp 11-22. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/007/01/0011-0022. Keywords. Cometary ...

  15. Comet 2001 Q2

    Czech Academy of Sciences Publication Activity Database

    Pravec, Petr; Kušnirák, Peter; Bouma, R. J.; Raymundo, P. M.

    č. 7687 (2001), s. 1 ISSN 0081-0304 R&D Projects: GA ČR GA205/99/0255 Institutional research plan: CEZ:AV0Z1003909 Keywords : comets * astrometry Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics

  16. Genetic Algorithm-Based Optimization to Match Asteroid Energy Deposition Curves

    Science.gov (United States)

    Tarano, Ana; Mathias, Donovan; Wheeler, Lorien; Close, Sigrid

    2018-01-01

    An asteroid entering Earth's atmosphere deposits energy along its path due to thermal ablation and dissipative forces that can be measured by ground-based and spaceborne instruments. Inference of pre-entry asteroid properties and characterization of the atmospheric breakup is facilitated by using an analytic fragment-cloud model (FCM) in conjunction with a Genetic Algorithm (GA). This optimization technique is used to inversely solve for the asteroid's entry properties, such as diameter, density, strength, velocity, entry angle, and strength scaling, from simulations using FCM. The previous parameters' fitness evaluation involves minimizing error to ascertain the best match between the physics-based calculated energy deposition and the observed meteors. This steady-state GA provided sets of solutions agreeing with literature, such as the meteor from Chelyabinsk, Russia in 2013 and Tagish Lake, Canada in 2000, which were used as case studies in order to validate the optimization routine. The assisted exploration and exploitation of this multi-dimensional search space enables inference and uncertainty analysis that can inform studies of near-Earth asteroids and consequently improve risk assessment.

  17. A Search of Reactivated Comets

    Science.gov (United States)

    Ye, Quan-Zhi

    2017-05-01

    Dormant or near-dormant short-period comets can unexpectedly regain the ability to eject dust. In many known cases, the resurrection is short-lived and lasts less than one orbit. However, it is possible that some resurrected comets can remain active in later perihelion passages. We search the archival images of various facilities to look for these “reactivated” comets. We identify two candidates, 297P/Beshore and 332P/Ikeya-Murakami, both of which were found to be inactive or weakly active in the previous orbit before their discovery. We derive a reactivation rate of ˜ 0.007 {{comet}}-1 {{orbit}}-1, which implies that typical short-period comets only become temporarily dormant a few times or less. Smaller comets are prone to rotational instability and may undergo temporary dormancy more frequently. Next generation high-cadence surveys may find more reactivation events of these comets.

  18. Cometography a catalog of comets

    CERN Document Server

    Kronk, Gary W; Seargent, David A J

    2017-01-01

    Cometography is a multi-volume catalog of every comet observed from ancient times up to the 1990s, when the internet took off as a medium of scientific record. It uses the most reliable orbits known to determine the distances from the Earth and Sun at the time of discovery and last observation, as well as the largest and smallest angular distance to the Sun, most northerly and southerly declination, closest distance to the Earth, and other details, to enable the reader to understand each comet's physical appearance. Volume 6, the final volume in the catalog, covers the observations and pertinent calculations for every comet seen between 1983 and 1993. The comets are listed in chronological order, with complete references to publications relating to each comet and physical descriptions of each comet's development throughout its apparition. Cometography is the definitive reference on comets through the ages, for astronomers and historians of science.

  19. Meteor-Shower on Mars Indicates Cometary Activity Far Away From the Sun

    Science.gov (United States)

    Sekhar, Aswin; ASHER, DAVID

    2015-08-01

    Introduction: The close encounter of Comet C/2013 A1 (Siding Spring) with Mars on 2014 Oct 19 at 1830h (UT) generated a lot of interest and modelling work [1] [2] [3] in the solar system community. A recent (on 2014 Nov 7) press release from NASA implied that a meteor shower was detected on Mars by their space instruments some hours after the comet-Mars close encounter. Various work [4] [5] [6] has suggested that very specific meteoroid sizes and ejection conditions may be required to produce meteor phenomena at Mars at the given times.Stream dynamics: Meteoroid stream modelling and their orbital geometry calculations have gained high precision over the years. In this work, we compute in detail the structure of the cloud of meteoroids released by C/2013 A1, showing its dependence on heliocentric ejection distances, 3-dimensional ejection velocities, and particle sizes. Our calculations using numerical integrator MERCURY, [7], incorporating radiation pressure, [8], show that ejection of particles at large heliocentric distances (about 7 au to 13 au) from C/2013 A1 could lead to evolution of a dense meteoroid cloud which intersects Mars a few hours after the comet-Mars close encounter. Hence this detection of a meteor shower on Mars by space instruments is an indirect confirmation of cometary activity at large distances which has rarely been observed directly by telescopes so far. Furthermore it shows that comprehensive threat estimation needs to be done for satellites orbiting the Earth when dynamically new comets come very close to the Earth in future.References:[1] Vaubaillon J., Macquet L., Soja R. 2014. MNRAS. 439: 3294.[2] Moorhead A. V., Wiegert P. A., Cooke W. J. 2014. Icarus. 231:13.[3] Ye Q.-Z., Hui M.-T., 2014, ApJ, 787: 115.[4] Farnocchia D. et al. 2014. ApJL. 790: 114.[5] Kelley M. S. P. et al. 2014, ApJL, 792: 16.[6] Tricarico P. et al., 2014, ApJL, 787: 35.[7] Chambers J. E. 1999. MNRAS. 304: 793.[8] Burns J. A, Lamy P. L., Soter S. 1979. Icarus. 40: 1.

  20. PRISMA, Italian network for meteors and atmospheric studies

    Science.gov (United States)

    Gardiol, D.; Cellino, A.; Di Martino, M.

    2016-01-01

    The aim of the PRISMA project is to develop the Italian participation in a network of European observing facilities whose primary targets are bright meteors (the so-called bolides and fireballs) and the recovery of meteorites. Several all-sky cameras have been recently installed in France (FRIPON project), and we propose to do the same in Italy, interconnecting the Italian network with the French one. Such a network is of great interest for the studies of interplanetary bodies and the dynamical and physical evolution of the population of small bodies of the Solar System and for the studies of collected meteorites. Those eventually recovered will be classified and investigated from the petrologic, genetic and evolutionary points of view, analyzed for their spectral characteristics and compared with known asteroids. The possibility to measure the radioactivity of samples shortly after the fall using gamma-ray spectrometers available in the Osservatorio Astrofisico di Torino laboratories, will allow us to reveal the presence of short-lived cosmogenic radioisotopes. PRISMA is also very suitable for the purposes of atmospheric studies. This includes the statistics of cloud coverage and lightning frequencies, as well as the comparison of the optical depth measured using satellites and PRISMA cameras.

  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. The asteroid lightcurve database

    Czech Academy of Sciences Publication Activity Database

    Warner, B. D.; Harris, A. W.; Pravec, Petr

    2009-01-01

    Roč. 202, č. 1 (2009), s. 134-146 ISSN 0019-1035 R&D Projects: GA ČR(CZ) GA205/05/0604 Institutional research plan: CEZ:AV0Z10030501 Keywords : asteroid s * rotation * photometry Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 3.340, year: 2009

  3. 67P, Singing Comet

    Science.gov (United States)

    Smirnova, Ekaterina

    2017-04-01

    I would like to propose to present a short science-art-music collaboration film called "67P, Singing Comet" (5:27 min). If time of the session will allow, prior to the film I would like to make a slide show introduction to this project, highlighting the inspiration - the mission Rosetta by the European Space Agency (ESA) - and the artistic collaboration that took place in creating this piece. Inspired by the ESA Rosetta mission to the comet 67P, Ekaterina Smirnova (artist and project director, New York), Lee Mottram (clarinetist, Wales), Takuto Fukuda (composer, Japan) and Brian Hekker (video editor, New York) collaborated to create a unique atmospheric piece. Water and the origins of life throughout the Universe (specifically the Earth) is an element of the mission and the focus of Ekaterina's artistic vision. Ekaterina literally and figuratively paints a sensory assemblage using a combination of synthetic and natural elements to shape this artistic creation. To paint her watercolor works she is using a replica of the water found on the comet and implementing her own heartbeat into the music to create a recognizable inward sound of life. The Electro-Acoustic composition by Takuto Fukuda features an electronically manipulated performance by clarinetist Lee Mottram. The piece ceremoniously begins with reverberant bursts of low-register atonal bells transporting the listener to their ethereal inner origins of body and mind. The imagination takes the experience to an unknown destination as it gains speed gliding through the visual and audible textures of space and time. The comet's water similarly reacts with an ebb and flow thawing ice to potentially give life a chance as it is thrust along an orbit around the Sun. Near then far from the heat the comet forms frozen particles from vapors as it reaches it's furthest stretches creating an aerodynamic tail of icicles that slowly dissipate in a cycle that repeats itself until the comet's ultimate collision with an

  4. Asteroid Kinetic Impactor Missions

    Science.gov (United States)

    Chesley, Steven

    2015-08-01

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

  5. Fluorescent in situ hybridization on comets: FISH comet.

    Science.gov (United States)

    Shaposhnikov, Sergey; El Yamani, Naouale; Collins, Andrew R

    2015-01-01

    The DNA in eukaryotic cells is organized into loop domains that represent basic structural and functional units of chromatin packaging. The comet assay, a sensitive method for monitoring DNA damage and repair, involves electrophoresis of nucleoids comprising supercoiled DNA attached to the nuclear matrix. Breaks in the DNA relax the supercoiling and allow DNA loops to expand, and on electrophoresis to move towards the anode, giving the appearance of a comet tail. We use fluorescent in situ hybridization (FISH) to investigate the structure of the chromatin within comet preparations and to study specific DNA sequences within comets. In this chapter we describe our FISH comets protocols, deal with some technical questions and outline the theory. FISH with comets should be useful to researchers interested in the structural organization of DNA and chromatin, the localization of DNA damage, and the kinetics of repair of damage.

  6. CINE: Comet INfrared Excitation

    Science.gov (United States)

    de Val-Borro, Miguel; Cordiner, Martin A.; Milam, Stefanie N.; Charnley, Steven B.

    2017-08-01

    CINE calculates infrared pumping efficiencies that can be applied to the most common molecules found in cometary comae such as water, hydrogen cyanide or methanol. One of the main mechanisms for molecular excitation in comets is the fluorescence by the solar radiation followed by radiative decay to the ground vibrational state. This command-line tool calculates the effective pumping rates for rotational levels in the ground vibrational state scaled by the heliocentric distance of the comet. Fluorescence coefficients are useful for modeling rotational emission lines observed in cometary spectra at sub-millimeter wavelengths. Combined with computational methods to solve the radiative transfer equations based, e.g., on the Monte Carlo algorithm, this model can retrieve production rates and rotational temperatures from the observed emission spectrum.

  7. Diatoms in comets

    Science.gov (United States)

    Hoover, R.; Hoyle, F.; Wallis, M. K.; Wickramasinghe, N. C.

    1986-01-01

    The fossil record of the microscopic algae classified as diatoms suggests they were injected to earth at the Cretaceous boundary. Not only could diatoms remain viable in the cometary environment, but also many species might replicate in illuminated surface layers or early interior layers of cometary ice. Presumably they reached the solar system on an interstellar comet as an already-evolved assemblage of organisms. Diatoms might cause color changes to comet nuclei while their outgassing decays and revives around highly elliptical orbits. Just as for interstellar absorption, high-resolution IR observations are capable of distinguishing whether the 10-micron feature arises from siliceous diatom material or mineral silicates. The 10-30-micron band and the UV 220-nm region can also provide evidence of biological material.

  8. Comet 81P/Wild 2 under a microscope

    Energy Technology Data Exchange (ETDEWEB)

    Brownlee, D; Tsou, P; Aleon, J; Alexander, C; Araki, T; Bajt, S; Baratta, G A; Bastien, R; Bland, P; Bleuet, P; Borg, J; Bradley, J P; Brearley, A; Brenker, F; Brennan, S; Bridges, J C; Browning, N; Brucato, J R; Bullock, E; Burchell, M J; Busemann, H; Butterworth, A; Chaussidon, M; Cheuvront, A; Chi, M; Cintala, M J; Clark, B C; Clemett, S J; Cody, G; Colangeli, L; Cooper, G; Cordier, P; Daghlian, C; Dai, Z R; D' Hendecourt, L; Djouadi, Z; Dominguez, G; Duxbury, T; Dworkin, J P; Ebel, D; Economou, T E; Fairey, S J; Fallon, S; Ferrini, G; Ferroir, T; Fleckenstein, H; Floss, C; Flynn, G; Franchi, I A; Fries, M; Gainsforth, Z; Gallien, J; Genge, M; Gilles, M K; Gillet, P; Gilmour, J; Glavin, D P; Gounelle, M; Grady, M M; Graham, G A; Grant, P G; Green, S F; Grossemy, F; Grossman, L; Grossman, J; Guan, Y; Hagiya, K; Harvey, R; Heck, P; Herzog, G F; Hoppe, P; Horz, F; Huth, J; Hutcheon, I D; Ishii, H; Ito, M; Jacob, D; Jacobsen, C; Jacobsen, S; Joswiak, D; Kearsley, A T; Keller, L; Khodja, H; Kilcoyne, A D; Kissel, J; Krot, A; Langenhorst, F; Lanzirotti, A; Le, L; Leshin, L; Leitner, J; Lemelle, L; Leroux, H; Liu, M; Luening, K; Lyon, I; MacPherson, G; Marcus, M A; Marhas, K; Matrajt, G; Meibom, A; Mennella, V; Messenger, K; Mikouchi, T; Mostefaoui, S; Nakamura, T; Nakano, T; Newville, M; Nittler, L R; Ohnishi, I; Ohsumi, K; Okudaira, K; Papanastassiou, D A; Palma, R; Palumbo, M E; Pepin, R O; Perkins, D; Perronnet, M; Pianetta, P; Rao, W; Rietmeijer, F; Robert, F; Rost, D; Rotundi, A; Ryan, R; Sandford, S A; Schwandt, C S; See, T H; Schlutter, D; Sheffield-Parker, J; Simionovici, A; Simon, S; Sitnitsky, I; Snead, C J; Spencer, M K; Stadermann, F J; Steele, A; Stephan, T; Stroud, R; Susini, J; Sutton, S R; Taheri, M; Taylor, S; Teslich, N; Tomeoka, K; Tomioka, N; Toppani, A; Trigo-Rodriguez, J M; Troadec, D; Tsuchiyama, A; Tuzolino, A J; Tyliszczak, T; Uesugi, K; Velbel, M; Vellenga, J; Vicenzi, E; Vincze, L; Warren, J; Weber, I; Weisberg, M; Westphal, A J; Wirick, S; Wooden, D; Wopenka, B; Wozniakiewicz, P; Wright, I; Yabuta, K; Yano, H; Young, E D; Zare, R N; Zega, T

    2006-10-12

    The Stardust spacecraft collected thousands of particles from comet 81P/Wild 2 and returned them to Earth for laboratory study. The preliminary examination of these samples shows that the nonvolatile portion of the comet is an unequilibrated assortment of materials that have both presolar and solar system origin. The comet contains an abundance of silicate grains that are much larger than predictions of interstellar grain models, and many of these are high-temperature minerals that appear to have formed in the inner regions of the solar nebula. Their presence in a comet proves that the formation of the solar system included mixing on the grandest scales. Stardust was the first mission to return solid samples from a specific astronomical body other than the Moon. The mission, part of the NASA Discovery program, retrieved samples from a comet that is believed to have formed at the outer fringe of the solar nebula, just beyond the most distant planet. The samples, isolated from the planetary region of the solar system for billions of years, provide new insight into the formation of the solar system. The samples provide unprecedented opportunities both to corroborate astronomical (remote sensing) and sample analysis information (ground truth) on a known primitive solar system body and to compare preserved building blocks from the edge of the planetary system with sample-derived and astronomical data for asteroids, small bodies that formed more than an order of magnitude closer to the Sun. The asteroids, parents of most meteorites, formed by accretion of solids in warmer, denser, more collisionally evolved inner regions of the solar nebula where violent nebular events were capable of flash-melting millimeter-sized rocks, whereas comets formed in the coldest, least dense region. The samples collected by Stardust are the first primitive materials from a known body, and as such they provide contextual insight for all primitive meteoritic samples. About 200 investigators

  9. Lunar Regolith Maturity Controlled By Ilmenite Content And Micro-Meteor Flux Variability

    Science.gov (United States)

    Schmitt, H. H.

    2013-12-01

    Synthesis of Is/FeO maturity indexes for Apollo 17 regolith samples in the valley of Taurus-Littrow on the Moon indicate that high levels of ilmenite in the samples significantly reduces the level of this indicator of space exposure. The analysis, along with consideration of regolith glass characteristics, also discloses that micro-meteor fluxes vary over geologic time, presumably in response to significant impact events in the Asteroid Belt. Surface samples of ilmenite-poor, silicate-rich regolith have about 80-90% higher maturity indexes than surface samples of ilmenite-rich, basaltic regolith of comparable exposure. For comparison of the history of various regolith exposures to the space environment, Taurus-Littrow's light mantle avalanche deposit, the youngest large area stratigraphic unit, provides a specific time horizon. For at least the last ~110 million years, the currently estimated age of the light mantle avalanche, most near surface (upper 1-5cm) regolith has had approximately the same exposure to micro-meteors. The surface of the largely ilmenite-rich basalt fill in the valley has been exposed to space at least as long or possibly 30 million years longer than the light mantle, based on exposure ages for large boulder ejecta in the Camelot cluster of craters. High apparent maturity (Is/FeO >80), however, exists only on three types of regolith surfaces: (1) the North Massif apron (e.g., 77431), (2) the light mantle avalanche deposit (e.g., 72161), and (3) low ilmenite basalt (e.g., 72150). Only intermediate to low maturity (Is/FeO Crater as a unit stratigraphically overlying the orange ash, has exceptionally low maturity (8% agglutinates and Is/FeO = 5) but an unusually high amount of "ropy" glass (14-18%). (Ropy glass normally constitutes less than on percent of new Taurus-Littrow regolith. It forms within fresh impact craters as a result of macro-meteor impacts, but the current flux of micro-meteors disaggregates such glass within a million years or

  10. Comet Radar Explorer

    Science.gov (United States)

    Asphaug, Erik; CORE Science Team

    2010-10-01

    Comet Radar Explorer (CORE) is a low cost mission that uses sounding radar to image the 3D internal structure of the nucleus of Jupiter-family comet (JFC) Tempel 2. Believed to originate in the Kuiper Belt, JFCs are among the most primitive bodies in the inner solar system. CORE operates a 5 and 15 MHz Radar Reflection Imager from close orbit about the nucleus of Tempel 2, obtaining a dense network of echoes that are used to map its interior dielectric contrasts to high resolution (ង m) and resolve the dielectric constants to  m throughout the 16x8x9 km nucleus. The resulting clear images of internal structure and composition reveal how the nucleus was formed and how it has evolved. Radiometric tracking of the spacecraft orbit results in an interior mass distribution that constrains the radar-based models of interior composition. High-resolution visible and infrared color images provide the surface and exterior boundary conditions for interior models and hypotheses. They present the geology and morphology of the nucleus surface at meter-scales, and also the time-evolving activity, structure and composition of the inner coma. By making deep connections from interior to exterior, the data CORE provides will answer fundamental questions about the earliest stages of planetesimal evolution and planet formation, and lay the foundation for a comet nucleus sample return mission. CORE is led by Prof. Erik Asphaug of the University of California, Santa Cruz and is managed by JPL. It benefits from key scientific and payload contributions by ASI and CNES. The international science team has been assembled on the basis of their key involvement in past and ongoing missions to comets, and in Mars radar missions, and for their expertise in radar data analysis.

  11. Comets and their origin the tools to decipher a comet

    CERN Document Server

    Meierhenrich, Uwe

    2014-01-01

    Divided into two parts, the first four chapters of Comets and their Origin refer to comets and their formation in general, describing cometary missions, comet remote observations, astrochemistry, artificial comets, and the chirality phenomenon.The second part covers the cometary Rosetta mission, its launch, journey, scientific objectives, and instrumentations, as well as the landing scenario on a cometary nucleus. Along the way, the author presents general questions concerning the origin of terrestrial water and the molecular beginnings of lifeon Earth, as well as how the instruments used on

  12. Advances in Meteoroid and Meteor Science

    CERN Document Server

    Trigo-Rodríguez, J. M; Llorca, J; Janches, D

    2008-01-01

    This volume is a compilation of articles that summarize the most recent results in meteor, meteoroid and related fields presented at the Meteoroids 2007 conference held at the impressive CosmoCaixa Science Museum in Barcelona, Spain. The conference took place between the 11th and the 15th of June and was organized by the Institute of Space Sciences (Consejo Superior de Investigaciones Científicas, CSIC) and the Institut d'Estudis Espacials de Catalunya (IEEC). Researchers in meteor science and supporting fields representing more than 20 countries participated at this international conference. The papers contained in this volume underwent the rigorous refereeing process, and they are good examples of the continuous progress being made in this research field. Technological advances in meteor and metoroid detection, the ever-increasing sophistication of computer modeling, and the proliferation of autonomous monitoring stations continue to create new niches for exciting research on meteoroids and their parent bo...

  13. The 2018 Meteor Shower Activity Forecast for Earth Orbit

    Science.gov (United States)

    Moorhead, Althea; Cooke, Bill; Moser, Danielle

    2017-01-01

    A number of meteor showers - the Ursids, Perseids, Leonids, eta Aquariids, Orionids, Draconids, and Andromedids - are predicted to exhibit increased rates in 2018. However, no major storms are predicted, and none of these enhanced showers outranks the typical activity of the Arietids, Southern delta Aquariids, and Geminids at small particle sizes. The MSFC stream model1 predicts higher than usual activity for the Ursid meteor shower in December 2018. While we expect an increase in activity, rates will fall short of the shower's historical outbursts in 1945 and 1986 when the zenithal hourly rate (ZHR) exceeded 100. Instead, the expected rate for 2018 is around 70. The Perseids, Leonids, eta Aquariids, and Orionids are expected to show mild enhancements over their baseline activity level in 2018. In the case of the Perseids, we may see an additional peak in activity a few hours before the traditional peak, but we do not expect activity levels as high as those seen in 2016 and 2017. The eta Aquariids and Orionids, which belong to a single meteoroid stream generated by comet 1P/Halley, are thought to have a 12-year activity cycle and are currently increasing in activity from year to year. Finally, we may see minor outbursts of the Draconids and Andromedids in 2018. Both showers have been difficult to model and have produced unexpected outbursts in recent years (the Draconids in 2012 and the Andromedids in 2011 and 2013). The Andromedids may produce two peaks, both of which are listed in Table 2. This document is designed to supplement spacecraft risk assessments that incorporate an annual averaged meteor shower flux (as is the case with all NASA meteoroid models). Results are presented relative to this baseline and are weighted to a constant kinetic energy. Two showers - the Daytime Arietids (ARI) and the Geminids (GEM) - attain flux levels approaching that of the baseline meteoroid environment for 0.1-cm-equivalent meteoroids. This size is the threshold for structural

  14. Meteor Beliefs Project: Notes from Coleridge and Doré

    Science.gov (United States)

    McBeath, Alastair

    2006-10-01

    Some meteorically-relevant lines from Coleridge's poem `The Rime of the Ancient Mariner' are discussed, presented with three of Dore's engraved illustrations to the poem, by way of concluding this Meteor Beliefs Project Hallowe'en Special.

  15. Contact Binary Asteroids

    Science.gov (United States)

    Rieger, Samantha

    2015-05-01

    Recent observations have found that some contact binaries are oriented such that the secondary impacts with the primary at a high inclination. This research investigates the evolution of how such contact binaries came to exist. This process begins with an asteroid pair, where the secondary lies on the Laplace plane. The Laplace plane is a plane normal to the axis about which the pole of a satellites orbit precesses, causing a near constant inclination for such an orbit. For the study of the classical Laplace plane, the secondary asteroid is in circular orbit around an oblate primary with axial tilt. This system is also orbiting the Sun. Thus, there are two perturbations on the secondarys orbit: J2 and third body Sun perturbations. The Laplace surface is defined as the group of orbits that lie on the Laplace plane at varying distances from the primary. If the secondary is very close to the primary, the inclination of the Laplace plane will be near the equator of the asteroid, while further from the primary the inclination will be similar to the asteroid-Sun plane. The secondary will lie on the Laplace plane because near the asteroid the Laplace plane is stable to large deviations in motion, causing the asteroid to come to rest in this orbit. Assuming the secondary is asymmetrical in shape and the bodys rotation is synchronous with its orbit, the secondary will experience the BYORP effect. BYORP can cause secular motion such as the semi-major axis of the secondary expanding or contracting. Assuming the secondary expands due to BYORP, the secondary will eventually reach the unstable region of the Laplace plane. The unstable region exists if the primary has an obliquity of 68.875 degrees or greater. The unstable region exists at 0.9 Laplace radius to 1.25 Laplace radius, where the Laplace radius is defined as the distance from the central body where the inclination of the Laplace plane orbit is half the obliquity. In the unstable region, the eccentricity of the orbit

  16. Modern Meteor Science An Interdisciplinary View

    CERN Document Server

    Hawkes, Robert; Brown, Peter

    2005-01-01

    This volume represents a blend of leading edge research and authoritative reviews in meteor science. It provides a comprehensive view of meteoroid research including the dynamics, sources and distribution of these bodies, and their chemistry and physical processes in the interplanetary medium and the Earth’s atmosphere. Techniques for investigation of meteor phenomena in the book include conventional and large aperture radar systems, spacecraft detection, optical systems, spectral measurements, and laboratory based interplanetary dust particle studies. The book will be of interest to researchers and students in astronomy, astrophysics, cosmochemistry, space engineering and space science. Cover photograph was taken by Masayuki Toda.

  17. Meteor wind observation at Kyoto Station

    International Nuclear Information System (INIS)

    Kato, S.; Aso, T.; Tsuda, T.

    1979-01-01

    Meteor wind observation at Kyoto Station has now collected a fairly large amount of data enough to enable to know the basic dynamic state at meteor heights over the station. Tidal and prevailing winds have been detected and their behavior seems now well understood on daily and seasonal basis. A comparison with observations at other stations suggests classical tidal theory to be relevant to explain the average state. Deviations from the mean present problems on the existence of various causes including hydromagnetic effects. Gravity waves would be an interesting subject in future study. (author)

  18. Asteroid Origins Satellite (AOSAT) I: An On-orbit Centrifuge Science Laboratory

    Science.gov (United States)

    Lightholder, Jack; Thoesen, Andrew; Adamson, Eric; Jakubowski, Jeremy; Nallapu, Ravi; Smallwood, Sarah; Raura, Laksh; Klesh, Andrew; Asphaug, Erik; Thangavelautham, Jekan

    2017-04-01

    Exploration of asteroids, comets and small moons (small bodies) can answer fundamental questions relating to the formation of the solar system, the availability of resources, and the nature of impact hazards. Near-earth asteroids and the small moons of Mars are potential targets of human exploration. But as illustrated by recent missions, small body surface exploration remains challenging, expensive, and fraught with risk. Despite their small size, they are among the most extreme planetary environments, with low and irregular gravity, loosely bound regolith, extreme temperature variation, and the presence of electrically charged dust. Here we describe the Asteroid Origins Satellite (AOSAT-I), an on-orbit, 3U CubeSat centrifuge using a sandwich-sized bed of crushed meteorite fragments to replicate asteroid surface conditions. Demonstration of this CubeSat will provide a low-cost pathway to physical asteroid model validation, shed light on the origin and geophysics of asteroids, and constrain the design of future landers, rovers, resource extractors, and human missions. AOSAT-I will conduct scientific experiments within its payload chamber while operating in two distinct modes: (1) as a nonrotating microgravity laboratory to investigate primary accretion, and (2) as a rotating centrifuge producing artificial milligravity to simulate surface conditions on asteroids, comets and small moons. AOSAT-I takes advantage of low-cost, off-the-shelf components, modular design, and the rapid assembly and instrumentation of the CubeSat standard, to answer fundamental questions in planetary science and reduce cost and risk of future exploration.

  19. Activity of the Leonid meteor shower on 2009 November 17

    Czech Academy of Sciences Publication Activity Database

    Koten, Pavel; Borovička, Jiří; Kokhirova, G.I.

    2011-01-01

    Roč. 528, April (2011), A94/1-A94/4 ISSN 0004-6361 R&D Projects: GA ČR GA205/09/1302 Institutional research plan: CEZ:AV0Z10030501 Keywords : meteor ites * meteor s * meteor oids Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 4.587, year: 2011

  20. 47 CFR 90.250 - Meteor burst communications.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Meteor burst communications. 90.250 Section 90... PRIVATE LAND MOBILE RADIO SERVICES Non-Voice and Other Specialized Operations § 90.250 Meteor burst communications. Meteor burst communications may be authorized for the use of private radio stations subject to...

  1. The 2014 KCG Meteor Outburst: Clues to a Parent Body

    Czech Academy of Sciences Publication Activity Database

    Moorhead, A.V.; Brown, P. G.; Spurný, Pavel; Cooke, W.; Shrbený, Lukáš

    2015-01-01

    Roč. 150, č. 4 (2015), 122/1-122/13 ISSN 0004-6256 Institutional support: RVO:67985815 Keywords : meteor ites * meteor s * meteor oids Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 4.617, year: 2015

  2. The activity of autumn meteor showers in 2006-2008

    Science.gov (United States)

    Kartashova, Anna

    2015-03-01

    The purpose of meteor observations in INASAN is the study of meteor showers, as the elements of the migrant substance of the Solar System, and estimation of risk of hazardous collisions of spacecrafts with the particles of streams. Therefore we need to analyze the meteor events with brightness of up to 8 m, which stay in meteoroid streams for a long time and can be a hazardous for the spacecraft. The results of our single station TV observations of autumn meteor showers for the period from 2006 to 2008 are presented. The high-sensitive hybrid camera (the system with coupled of the Image Intensifier) FAVOR with limiting magnitude for meteors about 9m. . .10m in the field of view 20 × 18 was used for observations. In 2006-2008 from October to November more than 3 thousand of meteors were detected, 65% from them have the brightness from 6m to 9m. The identification with autumn meteor showers (Orionids, Taurids, Draconids, Leonids) was carried out. In order to estimate the density of the influx of meteor matter to the Earth for these meteor showers the Index of meteor activity (IMA) was calculated. The IMA distribution for the period 2006 - 2008 is given. The distributions of autumn meteor showers (the meteors with brightness of up to 8 m) by stellar magnitude from 2006 to 2008 are also presented.

  3. 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.

  4. The Rafita asteroid family

    Science.gov (United States)

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

    2017-05-01

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

  5. A new proxy of comet impacts?

    Science.gov (United States)

    Kasatkina, E.; Shumilov, O.; Lukina, N.

    Environmental consequences of impacts by comets and asteroids depend on their sizes. The impact of 10 km sized asteroid killed off the dinosaurs 65 million years ago. A comet impact in AD 536 (>500 m diameter) caused a global climatic downturn. An impact of Tunguska-sized (50 m diameter) object (TO) could devastate a 2000 km -2 forest area, roughly the size of Moscow or New York. Among some misteries of the Tunguska event an important role plays the cause of the accelerated tree growth after 1908 in the catastrophe area. The main explanation is that an accelerated growth of old trees is a result of decrease of the level of competition due to falling of trees. We analyzed tree rings in larch samples collected in the Taymir region of Northern Siberia (72N; 105E) at a distance of about 1500 km to the North from the Tunguska catastrophe epicenter (61N; 102E). It was found that tree ring growth is 150% higher in 1908. We also analyzed all available Siberian tree-ring series (more than 100). It was found that there is a considerable increase of tree ring growth in 1908 over a huge area of Siberia (60N-75N; 60E-110E). It is obvious that the above mentioned interpretation could hardly explain the effect observed. Most likely the tree growth was stimulated by the TO matter spreaded over a large territory of Eurasia and introduced into the soil. It is generally believed that meteorites and comets delivered large amounts of organic to the early Earth. Another hypothesis is connected to NO produced during the Tunguska event. The cometary (probably fragment of the comet Enke) tail started to influence the Earth atmosphere several days before the fall of the meteorite causing optical anomalies observed mainly to the West from the place of TO explosion (Western Siberia, European Russia, Northern Europe). It is interesting that we've discovered nearly the similar, but smaller (about 50%) increase of tree ring growth connected to the Chulym bolide impact in 1984. The Chulym bolide

  6. ASTER: A Brazilian Mission to an Asteroid.

    Science.gov (United States)

    Winter, O. C.; Macau, E. E. N.; de Campos Velho, H.; Carruba, V.

    2012-05-01

    The first Brazilian mission to an asteroid is being planned. The target is the asteroid 2001 SN263, which has a NEA orbit of class AMOR. The mission is scheduled to be launched in 2015, reaching the asteroid in 2019.

  7. Meteor Shower Activity Derived from "Meteor Watching Public-Campaign" in Japan

    Science.gov (United States)

    Sato, M.; Watanabe, J.

    2011-01-01

    We tried to analyze activities of meteor showers from accumulated data collected by public campaigns for meteor showers which were performed as outreach programs. The analyzed campaigns are Geminids (in 2007 and 2009), Perseids (in 2008 and 2009), Quadrantids (in 2009) and Orionids (in 2009). Thanks to the huge number of reports, the derived time variations of the activities of meteor showers is very similar to those obtained by skilled visual observers. The values of hourly rates are about one-fifth (Geminids 2007) or about one-fourth (Perseids 2008) compared with the data of skilled observers, mainly due to poor observational sites such as large cities and urban areas, together with the immature skill of participants in the campaign. It was shown to be highly possible to estimate time variation in the meteor shower activity from our campaign.

  8. All-sky Meteor Orbit System AMOS and preliminary analysis of three unusual meteor showers

    Czech Academy of Sciences Publication Activity Database

    Tóth, J.; Kornoš, L.; Zigo, P.; Gajdoš, Š.; Kalmančok, D.; Világi, J.; Šimon, J.; Vereš, P.; Šilha, J.; Buček, M.; Galád, Adrián; Rusňák, P.; Hrábek, P.; Ďuriš, F.; Rudawska, R.

    2015-01-01

    Roč. 118, December (2015), s. 102-106 ISSN 0032-0633 Institutional support: RVO:67985815 Keywords : meteor * meteorite * meteoroid streams Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 1.942, year: 2015

  9. Asteroid Colors and their Variability

    Science.gov (United States)

    Jurić, M.; Ivezic, Z.; Lupton, R. H.; Szabo, G. M.; Quinn, T.; SDSS Collaboration

    2004-12-01

    While orbital dynamics of asteroids has been studied in great detail, we are just beginning to get a better grasp of their physical properties. Recently, SDSS has reinvigorated the research of asteroid color properties by producing a large volume of accurate color and variability data, to about 3 magnitudes fainter completeness limit than available before. To date, SDSS has observed over 200,000 moving objects in five photometric bands, a 2.5 orders of magnitude increase over previous multicolor surveys. About 43,000 of those have been associated with previously known asteroids that have well determined orbital elements. The resulting catalog (``SDSSMOC'') can be downloaded from http://www.sdss.org/science/. We will highlight some results enabled by SDSSMOC, such as the measurement of the main-belt asteroid size distribution to a significantly smaller size limit (<1 km) than possible before, a confirmation of the existence of a strong overall color gradient through the asteroid belt, and a demonstration that the colors of asteroids correlate with their dynamical family membership. We will also discuss the color variability of asteroids, interpreted as evidence for inhomogeneous albedo distribution over an asteroid's surface (``spottiness''), and the recent discovery of a color-age correlation which provides a direct evidence for space weathering, and offers a method to date asteroids using their SDSS colors.

  10. A brief visit from a red and extremely elongated interstellar asteroid.

    Science.gov (United States)

    Meech, Karen J; Weryk, Robert; Micheli, Marco; Kleyna, Jan T; Hainaut, Olivier R; Jedicke, Robert; Wainscoat, Richard J; Chambers, Kenneth C; Keane, Jacqueline V; Petric, Andreea; Denneau, Larry; Magnier, Eugene; Berger, Travis; Huber, Mark E; Flewelling, Heather; Waters, Chris; Schunova-Lilly, Eva; Chastel, Serge

    2017-12-21

    None of the approximately 750,000 known asteroids and comets in the Solar System is thought to have originated outside it, despite models of the formation of planetary systems suggesting that orbital migration of giant planets ejects a large fraction of the original planetesimals into interstellar space. The high predicted number density of icy interstellar objects (2.4 × 10 -4 per cubic astronomical unit) suggests that some should have been detected, yet hitherto none has been seen. Many decades of asteroid and comet characterization have yielded formation models that explain the mass distribution, chemical abundances and planetary configuration of the Solar System today, but there has been no way of telling whether the Solar System is typical of planetary systems. Here we report observations and analysis of the object 1I/2017 U1 ('Oumuamua) that demonstrate its extrasolar trajectory, and that thus enable comparisons to be made between material from another planetary system and from our own. Our observations during the brief visit by the object to the inner Solar System reveal it to be asteroidal, with no hint of cometary activity despite an approach within 0.25 astronomical units of the Sun. Spectroscopic measurements show that the surface of the object is spectrally red, consistent with comets or organic-rich asteroids that reside within the Solar System. Light-curve observations indicate that the object has an extremely oblong shape, with a length about ten times its width, and a mean radius of about 102 metres assuming an albedo of 0.04. No known objects in the Solar System have such extreme dimensions. The presence of 'Oumuamua in the Solar System suggests that previous estimates of the number density of interstellar objects, based on the assumption that all such objects were cometary, were pessimistically low. Planned upgrades to contemporary asteroid survey instruments and improved data processing techniques are likely to result in the detection of

  11. Long-period comet impact risk mitigation with Earth-based laser arrays

    Science.gov (United States)

    Zhang, Qicheng; Lubin, Philip M.; Hughes, Gary B.

    2017-09-01

    Long-period comets (LPCs) frequently transit the inner solar system, and like near-Earth asteroids (NEAs), pose a continued risk of impact with Earth. Unlike NEAs, LPCs follow nearly parabolic trajectories and approach from the distant outer solar system where they cannot be observed. An LPC on an Earth-impact trajectory is unlikely to be discovered more than a few years in advance of its arrival, even with significant advancements in sky survey detection capabilities, likely leaving insufficient time to develop and deliver an interception mission to deflect the comet. However, recent proposals have called for the development of one or more large ˜ 1 km laser arrays placed on or near Earth primarily as a means for photon propulsion of low-mass spacecraft at delta-v above what would be feasible by traditional chemical or ion propulsion methods. Such a laser array can also be directed to target and heat a threatening comet, sublimating its ices and activating jets of dust and vapor which alter the comet's trajectory in a manner similar to rocket propulsion. Simulations of directed energy comet deflection were previously developed from astrometric models of nongravitational orbital perturbations from solar heating, an analogous process that has been observed in numerous comets. These simulations are used together with the distribution of known LPC trajectories to evaluate the effect of an operational Earth-based laser array on the LPC impact risk.

  12. Technical manual for COMET

    International Nuclear Information System (INIS)

    Song, Jin Ho; Kwon, Young Min; Kim, Taek Mo; Lee, Sang Jong; Jeong, Hae Yong

    1996-07-01

    The purpose of this report is to provide a description for a COMET computer code which is to be used in the analysis of mass and energy releases during post-blowdown phase of LOCA. The mass and energy data re to be used as input data for the containment functional design. This report contains a brief description of analytical models and guidelines for the usage of the computer code. This computer code is to be used for both cold leg and hot leg break analyses. A verification analyses are performed for Ulchin 3 and 4 cold and hot leg break. 11 figs (Author)

  13. Physics of comets

    International Nuclear Information System (INIS)

    Swamy, K.S.K.

    1986-01-01

    This book deals systematically with the physics of comets in the light of our present knowledge about various aspects of cometary phenomena and the problems that require further attention. The basic aspects, methods and models that have been used extensively at the present time for the interpretation of cometary observations are fully discussed. Contents: General Introduction; Orbital Dynamics; Atomic Physics; Spectra; Spectra of Coma; Gas Production Rates; Dust Tail; Light Scattering Theory; Nature of the Dust Particle; Ion Tails; Nucleus; Origins; Problems and Prospects

  14. TRIGGERING SUBLIMATION-DRIVEN ACTIVITY OF MAIN BELT COMETS

    Energy Technology Data Exchange (ETDEWEB)

    Haghighipour, N. [Institute for Astronomy, University of Hawaii-Manoa, Honolulu, HI 96825 (United States); Maindl, T. I.; Dvorak, R. [Department of Astrophysics, University of Vienna, Türkenschanzstrasse 17, A-1180 Vienna (Austria); Schäfer, C. [Institut für Astronomie und Astrophysik, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 10, D-72076 Tübingen (Germany); Speith, R., E-mail: nader@ifa.hawaii.edu [Physikalisches Institut, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 14, D-72076 Tübingen (Germany)

    2016-10-10

    It has been suggested that the comet-like activity of main belt comets (MBCs) is due to the sublimation of sub-surface water–ice that has been exposed as a result of their surfaces being impacted by meter-sized bodies. We have examined the viability of this scenario by simulating impacts between meter-sized and kilometer-sized objects using a smooth particle hydrodynamics approach. Simulations have been carried out for different values of the impact velocity and impact angle, as well as different target material and water-mass fractions. Results indicate that for the range of impact velocities corresponding to those in the asteroid belt, the depth of an impact crater is slightly larger than 10 m, suggesting that if the activation of MBCs is due to the sublimation of sub-surface water–ice, this ice has to exist no deeper than a few meters from the surface. Results also show that ice exposure occurs in the bottom and on the interior surface of impact craters, as well as on the surface of the target where some of the ejected icy inclusions are re-accreted. While our results demonstrate that the impact scenario is indeed a viable mechanism to expose ice and trigger the activity of MBCs, they also indicate that the activity of the current MBCs is likely due to ice sublimation from multiple impact sites and/or the water contents of these objects (and other asteroids in the outer asteroid belt) is larger than the 5% that is traditionally considered in models of terrestrial planet formation, providing more ice for sublimation. We present the details of our simulations and discuss their results and implications.

  15. Main-belt Comet P/2012 T1 (PANSTARRS)

    Science.gov (United States)

    Hsieh, Henry H.; Kaluna, Heather M.; Novaković, Bojan; Yang, Bin; Haghighipour, Nader; Micheli, Marco; Denneau, Larry; Fitzsimmons, Alan; Jedicke, Robert; Kleyna, Jan; Vereš, Peter; Wainscoat, Richard J.; Ansdell, Megan; Elliott, Garrett T.; Keane, Jacqueline V.; Meech, Karen J.; Moskovitz, Nicholas A.; Riesen, Timm E.; Sheppard, Scott S.; Sonnett, Sarah; Tholen, David J.; Urban, Laurie; Kaiser, Nick; Chambers, K. C.; Burgett, William S.; Magnier, Eugene A.; Morgan, Jeffrey S.; Price, Paul A.

    2013-07-01

    We present initial results from observations and numerical analyses aimed at characterizing the main-belt comet P/2012 T1 (PANSTARRS). Optical monitoring observations were made between 2012 October and 2013 February using the University of Hawaii 2.2 m telescope, the Keck I telescope, the Baade and Clay Magellan telescopes, Faulkes Telescope South, the Perkins Telescope at Lowell Observatory, and the Southern Astrophysical Research Telescope. The object's intrinsic brightness approximately doubles from the time of its discovery in early October until mid-November and then decreases by ~60% between late December and early February, similar to photometric behavior exhibited by several other main-belt comets and unlike that exhibited by disrupted asteroid (596) Scheila. We also used Keck to conduct spectroscopic searches for CN emission as well as absorption at 0.7 μm that could indicate the presence of hydrated minerals, finding an upper limit CN production rate of Q CN 100 Myr and is unlikely to be a recently implanted interloper from the outer solar system, while a search for potential asteroid family associations reveals that it is dynamically linked to the ~155 Myr old Lixiaohua asteroid family. Some of the data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration, and made possible by the generous financial support of the W. M. Keck Foundation, the Magellan Telescopes located at Las Campanas Observatory, Chile, and the Southern Astrophysical Research (SOAR) telescope, which is a joint project of the Ministério da Ciência, Tecnologia, e Inovação (MCTI) da República Federativa do Brasil, the U.S. National Optical Astronomy Observatory (NOAO), the University of North Carolina at Chapel Hill (UNC), and Michigan State University (MSU).

  16. What the physical properties of near-Earth asteroids tell us about sources of their origin?

    Science.gov (United States)

    Lupishko, D. F.; di Martino, M.; Lupishko, T. A.

    2000-09-01

    It is generally recognized that main-belt asteroids (MBAs) and nuclei of extinct comets are two main sources for the near-Earth asteroids (NEAs) replenishment. Theoretical studies of NEA dynamics and numerical modelling of their orbital motions showed that so-called resonance mechanism for supplying NEAs is quite sufficient to sustain this population. The physical properties of NEAs and MBAs (and partly of comet nuclei) were compared to understand what the physical properties of NEAs can tell us about sources of their origin. The results of the comparison are given in this paper. The principal results of such a comparative analysis can be reduced to the following. All the NEAs have the small sizes, almost the same variety of their taxonomic classes and mineralogy, predominance of differentiated assemblages among them, approximately similar shape and rotation, optical properties and surface structure as compared to those of MBAs. All these conclusions clearly indicate that the main asteroid belt is the principal source of NEA, and comet nuclei contribution to the total NEA population does not exceed 10%. The NEAs 2100 Ra-Shalom, 2101 Adonis, 2201 Oljato, 2212 Hephaistos, 3200 Phaethon, 3552 Don Quixote and 4015 Wilson-Harrington are the most probable candidates for the cometary origin.

  17. Inside look at Halley's comet

    International Nuclear Information System (INIS)

    Beatty, J.K.

    1986-01-01

    The 1985-1986 emergence of Halley's comet, the first since the advent of the space age, was explored by a variety of spacecraft. The Vega 1, launched by the USSR together with the Eastern-block alliance, passed 5523 miles from the comet's nucleus at 7:20:06 Universal time. It indicated that the comet was about 300 miles closer to the sun than had been predicted. The Japanese spacecraft, Suisei, was created to map the distribution of neutral hydrogen atoms outside Halley's visible coma. Its pictures indicated that the comet's output of water varied between 25 and 60 tons per second. Five days after the Vega 2's passage through the comet, the Giotto (sponsored by the European Space Agency) probe appeared. Giotto's close approach took place 3.1 minutes after midnight UT on March 14th; the craft had passed 376 miles from its target. Giotto's data indicated that the nucleus was bigger than expected, and that the comet was composed primarily of water, CO2 and N2. The Vegas and Giotto found that as the solar wind approaches Halley, it slows gradually and the solar magnetic lines embedded in the wind begin to pile up. Pick-up ions, from the comet's halo of neutral hydrogen, were found in this solar wind. Sensors on the Vega spacecraft found a variety of plasma waves propagating inside the bow wave. In order to synthesize all the results, a conference on the exploration of Halley's comet will be held this October

  18. Detecting active comets with SDSS

    Energy Technology Data Exchange (ETDEWEB)

    Solontoi, Michael; Ivezic, Zeljko; /Washington U., Seattle, Astron. Dept.; West, Andrew A.; /MIT, MKI; Claire, Mark; /Washington U., Seattle, Astron. Dept.; Juric, Mario; /Princeton U. Observ.; Becker, Andrew; Jones, Lynne; /Washington U., Seattle, Astron. Dept.; Hall, Patrick B.; /York U., Canada; Kent, Steve; /Fermilab; Lupton, Robert H.; /Princeton U. Observ.; Quinn, Tom; /Washington U., Seattle, Astron. Dept. /Princeton U. Observ.

    2010-12-01

    Using a sample of serendipitously discovered active comets in the Sloan Digital Sky Survey (SDSS), we develop well-controlled selection criteria for greatly increasing the efficiency of comet identification in the SDSS catalogs. After follow-up visual inspection of images to reject remaining false positives, the total sample of SDSS comets presented here contains 19 objects, roughly one comet per 10 million other SDSS objects. The good understanding of selection effects allows a study of the population statistics, and we estimate the apparent magnitude distribution to r {approx} 18, the ecliptic latitude distribution, and the comet distribution in SDSS color space. The most surprising results are the extremely narrow range of colors for comets in our sample (e.g. root-mean-square scatter of only {approx}0.06 mag for the g-r color), and the similarity of comet colors to those of jovian Trojans. We discuss the relevance of our results for upcoming deep multi-epoch optical surveys such as the Dark Energy Survey, Pan-STARRS, and the Large Synoptic Survey Telescope (LSST), and estimate that LSST may produce a sample of about 10,000 comets over its 10-year lifetime.

  19. AIDA: Asteroid Impact & Deflection Assessment

    Science.gov (United States)

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

    2012-12-01

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

  20. `Supernova' 185 is Really a Nova Plus Comet P/Swift-Tuttle

    Science.gov (United States)

    Schaefer, Bradley E.

    1995-10-01

    The Chinese History of the Later Han Dynasty reports on a guest star which appeared on 7 December AD 185. This has been widely accepted as a supernova, although the identify of the remnant is much debated. As such, this report has been extensively used to date supernova remnants, pulsars, and even to measure the Hubble Constant. Recently, Chin & Huang have claimed that the Chinese report is actually of some unknown comet that was visible for >210 days. Both the supernova and comet hypotheses have major problems. These problems are avoided if the Chinese report is a concatenation of two events in the same region of the sky, the first being a nova and the second being a comet. In fact, one of the brightest and most famous comets (Comet P/Swift-Tuttle, the parent of the Perseid meteor shower that will have a near approach to Earth on 2126 August 5) had a rare favorable apparition with a disappearance at the correct time and place as reported.

  1. Development of a miniature scanning electron microscope for in-flight analysis of comet dust

    Science.gov (United States)

    Conley, J. M.; Bradley, J. G.; Giffin, C. E.; Albee, A. L.; Tomassian, A. D.

    1983-01-01

    A description is presented of an instrument which was developed with the original goal of being flown on the International Comet Mission, scheduled for a 1985 launch. The Scanning Electron Microscope and Particle Analyzer (SEMPA) electron miniprobe is a miniaturized electrostatically focused electron microscope and energy dispersive X-ray analyzer for in-flight analysis of comet dust particles. It was designed to be flown on board a comet rendezvous spacecraft. Other potential applications are related to asteroid rendezvous and planetary lander missions. According to the development objectives, SEMPA miniprobe is to have the capability for imaging and elemental analysis of particles in the size range of 0.25 microns and larger.

  2. Multiwavelength Observations of Recent Comets

    Science.gov (United States)

    Milam, Stefanie N.; Charnley, Steven B.; Gicquel, Adeline; Cordiner, Martin; Kuan, Yi-Jehng; Chuang, Yo-Ling; Villanueva, Geronimo; DiSanti, Michael A.; Bonev, Boncho P.; Remijan, Anthony J.; hide

    2013-01-01

    Comets provide important clues to the physical and chemical processes that occurred during the formation and early evolution of the Solar System, and could also have been important for initiating prebiotic chemistry on the early Earth. Comets are comprised of molecular ices, that may be pristine inter-stellar remnants of Solar System formation, along with high-temperature crystalline silicate dust that is indicative of a more thermally varied history in the protosolar nebula. Comparing abundances of cometary parent volatiles, and isotopic fractionation ratios, to those found in the interstellar medium, in disks around young stars, and between cometary families, is vital to understanding planetary system formation and the processing history experienced by organic matter in the so-called interstellar-comet connection. We will present a comparison of molecular abundances in these comets to those observed in others, supporting a long-term effort of building a comet taxonomy based on composition.

  3. Genetic Algorithm-based Optimization to Match Asteroid Energy Deposition Curves

    Science.gov (United States)

    Tarano, Ana Maria; Mathias, Donovan; Wheeler, Lorien; Close, Sigrid

    2017-10-01

    An asteroid entering Earth’s atmosphere deposits energy along its path due to thermal ablation and dissipative forces that can be measured by ground-based and space-borne instruments. Inference of pre-entry asteroid properties and characterization of the atmospheric breakup is facilitated by using an analytic fragment-cloud model (FCM) in conjunction with a Genetic Algorithm (GA). This optimization technique is used to inversely solve for the asteroid’s entry properties, such as diameter, density, strength, velocity, entry angle, ablation coefficient, and strength scaling, from simulations using FCM. The previous parameters’ fitness evaluation involves minimizing residuals and comparing the incremental energy deposited to ascertain the best match between the physics-based calculated energy deposition and the observed meteors. This steady-state GA provided sets of solutions agreeing with literature, such as the meteor from Chelyabinsk, Russia in 2013 and Tagish Lake, Canada in 2000, which were used as case studies in order to validate the optimization routine. The assisted exploration and exploitation of this multi-dimensional search space enables inference and uncertainty analysis that can inform studies of near-Earth asteroids and consequently improve risk assessment.

  4. Significantly high polarization degree of the very low-albedo asteroid (152679) 1998 KU2

    Science.gov (United States)

    Kuroda, Daisuke; Ishiguro, Masateru; Watanabe, Makoto; Hasegawa, Sunao; Sekiguchi, Tomohiko; Naito, Hiroyuki; Usui, Fumihiko; Imai, Masataka; Sato, Mitsuteru; Kuramoto, Kiyoshi

    2018-03-01

    We present a unique and significant polarimetric result regarding the near-Earth asteroid (152679) 1998 KU2, which has a very low geometric albedo. From our observations, we find that the linear polarization degrees of 1998 KU2 are 44.6 ± 0.5% in the RC band and 44.0 ± 0.6% in the V band at a solar phase angle of 81.0°. These values are the highest of any known airless body in the solar system (i.e., high-polarization comets, asteroids, and planetary satellites) at similar phase angles. This polarimetric observation is not only the first for primitive asteroids at large phase angles, but also for low-albedo (Based on spectroscopic similarities and polarimetric measurements of materials that have been sorted by size in previous studies, we conjecture that 1998 KU2 has a highly microporous regolith structure comprising nano-sized carbon grains on the surface.

  5. Near-Earth Asteroid Tracking with the Maui Space Surveillance System (NEAT/MSSS)

    Science.gov (United States)

    Helin, Eleanor F.; Pravdo, Steven H.; Lawrence, Kenneth J.; Hicks, Michael D.

    2001-01-01

    Over the last year the Jet Propulsion Laboratory's (JPL) Near-Earth Asteroid Tracking (NEAT) program has made significant progress and now consists of two simultaneously-operating, autonomous search systems on the 1.2-m (48") telescopes: on the Maui Space Surveillance System (NEAT/MSSS) and NEAT/Palomar on the Palomar Observatory's Oschin telescope. This paper will focus exclusively on the NEAT/MSSS system. NEAT/MSSS is operated as a partnership between NASA/JPL and the United States Air Force Research Laboratory (AFRL), utilizing the AFRL 1.2-m telescope on the 3000-m summit of Haleakala, Maui, The USAF Space Command (SPCMD) contributed financial support to build and install the 'NEAT focal reducer' on the MSSS 1.2-m telescope giving it a large field of view (2.5 square degrees), suitable for the near-earth object (NEO),both asteroids and comets, survey. This work was completed in February 2000. AFRL has made a commitment to NEAT/MSSS that allows NEAT to operate full time with the understanding that AFRL participate as partners in NEAT/MSSS and have use of the NEAT camera system for high priority satellite observations during bright time (parts of 12 nights each month). Currently, NEAT has discovered 42 NEAs including 12 larger than 1-km, 5 Potentially Hazardous Asteroids (PHAs), 6 comets, and nearly 25,000 asteroid detections since March 2000.

  6. Rosetta - a comet ride to solve planetary mysteries

    Science.gov (United States)

    2003-01-01

    be kept in hibernation during most of its 8-year trek towards Wirtanen. What makes Rosetta's cruise so long? To reach Comet Wirtanen, the spacecraft needs to go out in deep space as far from the Sun as Jupiter is. No launcher could possibly get Rosetta there directly. ESA's spacecraft will gather speed from gravitational ‘kicks’ provided by three planetary fly-bys: one of Mars in 2005 and two of Earth in 2005 and 2007. During the trip, Rosetta will also visit two asteroids, Otawara (in 2006) and Siwa (in 2008). During these encounters, scientists will switch on Rosetta's instruments for calibration and scientific studies. Long trips in deep space include many hazards, such as extreme changes in temperature. Rosetta will leave the benign environment of near-Earth space to the dark, frigid regions beyond the asteroid belt. To manage these thermal loads, experts have done very tough pre-launch tests to study Rosetta's endurance. For example, they have heated its external surfaces to more than 150°C, then quickly cooled it to -180°C in the next test. The spacecraft will be fully reactivated prior to the comet rendezvous manoeuvre in 2011. Then, Rosetta will orbit the comet - an object only 1.2 km wide - while it cruises through the inner Solar System at 135 000 kilometres per hour. At that time of the rendezvous - around 675 million km from the Sun - Wirtanen will hardly show any surface activity. It means that the carachteristic coma (the comet’s ‘atmosphere’) and the tail will not be formed yet, because of the large distance from the Sun. The comet's tail is in fact made of dust grains and frozen gases from the comet's surface that vapourise because of the Sun's heat. During 6-month, Rosetta will extensively map the comet surface, prior to selecting a landing site. In July 2012, the lander will self-eject from the spacecraft from a height of just one kilometre. Touchdown will take place at walking speed - less than 1 metre per second. Immediately after

  7. NEOWISE Reactivation Mission Year Three: Asteroid Diameters and Albedos

    Energy Technology Data Exchange (ETDEWEB)

    Masiero, Joseph R.; Mainzer, A. K.; Kramer, E. [Jet Propulsion Laboratory/California Institute of Technology, 4800 Oak Grove Drive, MS 183-301, Pasadena, CA 91109 (United States); Nugent, C.; Cutri, R. M. [California Institute of Technology, Infrared Processing and Analysis Center, 1200 California Boulevard, Pasadena, CA 91125 (United States); Wright, E. L. [University of California, Los Angeles, CA 90095 (United States); Bauer, J. M. [University of Maryland, College Park, MD 20742 (United States); Grav, T.; Sonnett, S., E-mail: Joseph.Masiero@jpl.nasa.gov [Planetary Science Institute, 1700 E Fort Lowell Road #106, Tucson, AZ 85719 (United States)

    2017-10-01

    The Near-Earth Object Wide-field Infrared Survey Explorer (NEOWISE) reactivation mission has completed its third year of surveying the sky in the thermal infrared for near-Earth asteroids and comets. NEOWISE collects simultaneous observations at 3.4 and 4.6  μ m of solar system objects passing through its field of regard. These data allow for the determination of total thermal emission from bodies in the inner solar system, and thus the sizes of these objects. In this paper, we present thermal model fits of asteroid diameters for 170 NEOs and 6110 Main Belt asteroids (MBAs) detected during the third year of the survey, as well as the associated optical geometric albedos. We compare our results with previous thermal model results from NEOWISE for overlapping sample sets, as well as diameters determined through other independent methods, and find that our diameter measurements for NEOs agree to within 26% (1 σ ) of previously measured values. Diameters for the MBAs are within 17% (1 σ ). This brings the total number of unique near-Earth objects characterized by the NEOWISE survey to 541, surpassing the number observed during the fully cryogenic mission in 2010.

  8. On the Origins of Earth-Approaching Asteroids

    Science.gov (United States)

    Lupishko, D. F.; Lupishko, T. A.

    2001-05-01

    It is generally accepted that Main-Belt asteroids (MBAs) and nuclei of no longer active comets are the sources that replenish the Amor, Apollo, and Aten groups of asteroids, i.e., Earth-approaching asteroids (EAAs). Investigations of the dynamics of EAAs and numerical modeling of their orbital motion have shown that the so-called resonance mechanism of the replenishment of the EAA population with objects from the Main Belt is quite sufficient for its maintenance. In this paper, we compare the physical properties of EAAs and MBAs (and, partly, cometary nuclei) in an effort to gain an understanding of whether the physical properties of EAAs can tell us anything about their origins. The principal result of the performed analysis is the conclusion that the small dimensions of EAAs; their MBA-identical set of taxonomic classes; the identical mineralogy and preponderance of differentiated compositions among EAAs; and their, on average, MBA-identical shape, rotation, optical properties, and surface structure are all convincing proof that the Main Belt is the dominant source of the replenishment of the EAA population and that the share of cometary-origin EAAs does not exceed 10%. The most likely candidates for cometary-origin objects among EAAs are 2100 Ra-Shalom, 2101 Adonis, 2201 Oljato, 2212 Hephaistos, 3200 Phaethon, 3552 Don Quixote, and 4015 Wilson-Harrington.

  9. Asteroid electrostatic instrumentation and modelling

    Energy Technology Data Exchange (ETDEWEB)

    Aplin, K L; Bowles, N E; Urbak, E [Department of Physics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH (United Kingdom); Keane, D; Sawyer, E C, E-mail: k.aplin1@physics.ox.ac.uk [RAL Space, R25, Harwell Oxford, Didcot OX11 0QX (United Kingdom)

    2011-06-23

    Asteroid surface material is expected to become photoelectrically charged, and is likely to be transported through electrostatic levitation. Understanding any movement of the surface material is relevant to proposed space missions to return samples to Earth for detailed isotopic analysis. Motivated by preparations for the Marco Polo sample return mission, we present electrostatic modelling for a real asteroid, Itokawa, for which detailed shape information is available, and verify that charging effects are likely to be significant at the terminator and at the edges of shadow regions for the Marco Polo baseline asteroid, 1999JU3. We also describe the Asteroid Charge Experiment electric field instrumentation intended for Marco Polo. Finally, we find that the differing asteroid and spacecraft potentials on landing could perturb sample collection for the short landing time of 20min that is currently planned.

  10. Interferometric Meteor Head Echo Observations using the Southern Argentina Agile Meteor Radar (SAAMER)

    Science.gov (United States)

    Janches, D.; Hocking, W.; Pifko, S.; Hormaechea, J. L.; Fritts, D. C.; Brunini, C; Michell, R.; Samara, M.

    2013-01-01

    A radar meteor echo is the radar scattering signature from the free-electrons in a plasma trail generated by entry of extraterrestrial particles into the atmosphere. Three categories of scattering mechanisms exist: specular, nonspecular trails, and head-echoes. Generally, there are two types of radars utilized to detect meteors. Traditional VHF meteor radars (often called all-sky1radars) primarily detect the specular reflection of meteor trails traveling perpendicular to the line of sight of the scattering trail, while High Power and Large Aperture (HPLA) radars efficiently detect meteor head-echoes and, in some cases, non-specular trails. The fact that head-echo measurements can be performed only with HPLA radars limits these studies in several ways. HPLA radars are very sensitive instruments constraining the studies to the lower masses, and these observations cannot be performed continuously because they take place at national observatories with limited allocated observing time. These drawbacks can be addressed by developing head echo observing techniques with modified all-sky meteor radars. In addition, the fact that the simultaneous detection of all different scattering mechanisms can be made with the same instrument, rather than requiring assorted different classes of radars, can help clarify observed differences between the different methodologies. In this study, we demonstrate that such concurrent observations are now possible, enabled by the enhanced design of the Southern Argentina Agile Meteor Radar (SAAMER) deployed at the Estacion Astronomica Rio Grande (EARG) in Tierra del Fuego, Argentina. The results presented here are derived from observations performed over a period of 12 days in August 2011, and include meteoroid dynamical parameter distributions, radiants and estimated masses. Overall, the SAAMER's head echo detections appear to be produced by larger particles than those which have been studied thus far using this technique.

  11. Giant comets and mass extinctions of life

    Science.gov (United States)

    Napier, W. M.

    2015-03-01

    I find evidence for clustering in age of well-dated impact craters over the last 500 Myr. At least nine impact episodes are identified, with durations whose upper limits are set by the dating accuracy of the craters. Their amplitudes and frequency are inconsistent with an origin in asteroid breakups or Oort cloud disturbances, but are consistent with the arrival and disintegration in near-Earth orbits of rare, giant comets, mainly in transit from the Centaur population into the Jupiter family and Encke regions. About 1 in 10 Centaurs in Chiron-like orbits enter Earth-crossing epochs, usually repeatedly, each such epoch being generally of a few thousand years' duration. On time-scales of geological interest, debris from their breakup may increase the mass of the near-Earth interplanetary environment by two or three orders of magnitude, yielding repeated episodes of bombardment and stratospheric dusting. I find a strong correlation between these bombardment episodes and major biostratigraphic and geological boundaries, and propose that episodes of extinction are most effectively driven by prolonged encounters with meteoroid streams during bombardment episodes. Possible mechanisms are discussed.

  12. Modeling the seismic response of 2D models of asteroid 433 Eros, based on the spectral-element method.

    Science.gov (United States)

    Blitz, Celine; Komatitsch, Dimitri; Lognonné, Philippe; Martin, Roland; Le Goff, Nicolas

    The understanding of the interior structure of Near Earth Objects (NEOs) is a fundamental issue to determine their evolution and origin, and also, to design possible mitigation techniques (Walker and Huebner, 2004). Indeed, if an oncoming Potentially Hazardous Object (PHO) were to threaten the Earth, numerous methods are suggested to prevent it from colliding our planet. Such mitigation techniques may involve nuclear explosives on or below the object surface, impact by a projectile, or concentration of solar energy using giant mirrors (Holsapple, 2004). The energy needed in such mitigation techniques highly depends on the porosity of the hazardous threatening object (asteroid or comet), as suggested by Holsapple, 2004. Thus, for a given source, the seismic response of a coherent homogeneous asteroid should be very different from the seismic response of a fractured or rubble-pile asteroid. To assess this hypothesis, we performed numerical simulations of wave propagation in different interior models of the Near Earth Asteroid 433 Eros. The simulations of wave propagation required a shape model of asteroid Eros, kindly provided by A. Cheng and O. Barnouin-Jha (personal communication). A cross-section along the longest axis has been chosen to define our 2D geometrical model, and we study two models of the interior: a homogeneous one, and a complex one characterized by fault networks below the main crosscut craters, and covered by a regolith layer of thickness ranging from 50 m to 150 m. To perform the numerical simulations we use the spectral-element method, which solves the variational weak form of the seismic wave equation (Komatitsch and Tromp, 1999) on the meshes of the 2D models of asteroid Eros. The homogeneous model is composed of an elastic material characterized by a pressure wave velocity Vp = 3000 m.s-1 , a shear wave velocity Vs = 1700 m.s-1 and a density of 2700 kg.m-3 . The fractured model possesses the same characteristics except for the presence of

  13. Data processing of records of meteoric echoes

    Science.gov (United States)

    Dolinský, P.

    2016-01-01

    The data obtained in the period from 4 November 2014 to 31 July 2014 by our receiving and recording system was statistically processed. The system records meteoric echoes from the TV transmitter Lviv 49.739583 MHz (N49.8480° E24.0369°, Ukraine) using a 4-element Yagi antenna with horizontal polarization (elevation of 0° and azimuth of 60°), receiver ICOM R-75 in the CW mode, and a computer with a recording using HROFFT v1.0.0f. The main goal was to identify weak showers in these data. Mayor or strong showers are visible without processing (referred at IMC2015, Mistelbach). To find or to identify weaker showers is more difficult. Not all echoes are meteoric echoes, but also ionospheric echoes or lightning disturbances are present.

  14. Multicolor photometry of a meteor with flares

    International Nuclear Information System (INIS)

    Benyukh, V.V.

    1980-01-01

    In various spectral regions the intensity variations are studied along the track of a base meteor with three flares having the character of spherical explosion. The concentration of radiating atoms in the flare is estimated. In the moment of the first flare there was a sharp intensity increase in the red region of spectrum. In two other flares the radiation in the interval 4400-4700 A is predominated. During all the three flares which continued 0.04 s, the meteoric body lost 40% of its initial mass. The concentration of Mg 2 atoms (4481 A) which gave the main contribution into the intensity of the third, brightest flare in blue spectral region, is found to be 1x10 11 cm -3

  15. Meteor detection on ST (MST) radars

    International Nuclear Information System (INIS)

    Avery, S.K.

    1987-01-01

    The ability to detect radar echoes from backscatter due to turbulent irregularities of the radio refractive index in the clear atmosphere has lead to an increasing number of established mesosphere - stratosphere - troposphere (MST or ST) radars. Humidity and temperature variations are responsible for the echo in the troposphere and stratosphere and turbulence acting on electron density gradients provides the echo in the mesosphere. The MST radar and its smaller version, the ST radar, are pulsed Doppler radars operating in the VHF - UHF frequency range. These echoes can be used to determine upper atmosphere winds at little extra cost to the ST radar configuration. In addition, the meteor echoes can supplement mesospheric data from an MST radar. The detection techniques required on the ST radar for delineating meteor echo returns are described

  16. EPOXI at comet Hartley 2.

    Science.gov (United States)

    A'Hearn, Michael F; Belton, Michael J S; Delamere, W Alan; Feaga, Lori M; Hampton, Donald; Kissel, Jochen; Klaasen, Kenneth P; McFadden, Lucy A; Meech, Karen J; Melosh, H Jay; Schultz, Peter H; Sunshine, Jessica M; Thomas, Peter C; Veverka, Joseph; Wellnitz, Dennis D; Yeomans, Donald K; Besse, Sebastien; Bodewits, Dennis; Bowling, Timothy J; Carcich, Brian T; Collins, Steven M; Farnham, Tony L; Groussin, Olivier; Hermalyn, Brendan; Kelley, Michael S; Kelley, Michael S; Li, Jian-Yang; Lindler, Don J; Lisse, Carey M; McLaughlin, Stephanie A; Merlin, Frédéric; Protopapa, Silvia; Richardson, James E; Williams, Jade L

    2011-06-17

    Understanding how comets work--what drives their activity--is crucial to the use of comets in studying the early solar system. EPOXI (Extrasolar Planet Observation and Deep Impact Extended Investigation) flew past comet 103P/Hartley 2, one with an unusually small but very active nucleus, taking both images and spectra. Unlike large, relatively inactive nuclei, this nucleus is outgassing primarily because of CO(2), which drags chunks of ice out of the nucleus. It also shows substantial differences in the relative abundance of volatiles from various parts of the nucleus.

  17. A Global Atmospheric Model of Meteoric Iron

    Science.gov (United States)

    Feng, Wuhu; Marsh, Daniel R.; Chipperfield, Martyn P.; Janches, Diego; Hoffner, Josef; Yi, Fan; Plane, John M. C.

    2013-01-01

    The first global model of meteoric iron in the atmosphere (WACCM-Fe) has been developed by combining three components: the Whole Atmosphere Community Climate Model (WACCM), a description of the neutral and ion-molecule chemistry of iron in the mesosphere and lower thermosphere (MLT), and a treatment of the injection of meteoric constituents into the atmosphere. The iron chemistry treats seven neutral and four ionized iron containing species with 30 neutral and ion-molecule reactions. The meteoric input function (MIF), which describes the injection of Fe as a function of height, latitude, and day, is precalculated from an astronomical model coupled to a chemical meteoric ablation model (CABMOD). This newly developed WACCM-Fe model has been evaluated against a number of available ground-based lidar observations and performs well in simulating the mesospheric atomic Fe layer. The model reproduces the strong positive correlation of temperature and Fe density around the Fe layer peak and the large anticorrelation around 100 km. The diurnal tide has a significant effect in the middle of the layer, and the model also captures well the observed seasonal variations. However, the model overestimates the peak Fe+ concentration compared with the limited rocket-borne mass spectrometer data available, although good agreement on the ion layer underside can be obtained by adjusting the rate coefficients for dissociative recombination of Fe-molecular ions with electrons. Sensitivity experiments with the same chemistry in a 1-D model are used to highlight significant remaining uncertainties in reaction rate coefficients, and to explore the dependence of the total Fe abundance on the MIF and rate of vertical transport.

  18. Meteors, space aliens, and other exotic encounters

    Science.gov (United States)

    Tom. Hofacker

    1998-01-01

    Exotics have had a big impact on our environment. If you do not think so, just look at how many people believe that humans would not exist on this planet were it not for exotics. This belief centers on two main theories: (1) that humans could not have evolved were it not for a huge meteor from outer space striking the earth resulting in extinction of the dinasours, the...

  19. Structural peculiarities of the Quadrantid meteor shower

    Science.gov (United States)

    Isamutdinov, Sh. O.; Chebotarev, R. P.

    1987-01-01

    Systematic radio observations to investigate the Quadrantid meteor shower structure are regularly carried out. They have now been conducted annually in the period of its maximum activity, January 1 to 6, since 1966. The latest results of these investigations are presented, on the basis of 1981 to 1984 data obtained using new equipment with a limiting sensitivity of +7.7 sup m which make it possible to draw some conclusions on the Quadrantids shower structure both for transverse and lengthwise directions.

  20. Impact mechanics at Meteor Crater, Arizona

    Science.gov (United States)

    Shoemaker, Eugene Merle

    1959-01-01

    Meteor Crator is a bowl-shaped depression encompassed by a rim composed chiefly of debris stacked in layers of different composition. Original bedrock stratigraphy is preserved, inverted, in the debris. The debris rests on older disturbed strata, which are turned up at moderate to steep angles in the wall of the crater and are locally overturned near the contact with the debris. These features of Meteor Crater correspond closely to those of a crater produced by nuclear explosion where depth of burial of the device was about 1/5 the diameter of the resultant crater. Studies of craters formed by detonation of nuclear devices show that structures of the crater rims are sensitive to the depth of explosion scaled to the yield of the device. The structure of Meteor Crater is such as would be produced by a very strong shock originating about at the level of the present crater floor, 400 feet below the original surface. At supersonic to hypersonic velocity an impacting meteorite penetrates the ground by a complex mechanism that includes compression of the target rocks and the meteorite by shock as well as hydrodynamic flow of the compressed material under high pressure and temperature. The depth of penetration of the meteorite, before it loses its integrity as a single body, is a function primarily of the velocity and shape of the meteorite and the densities and equations of state of the meteorite and target. The intensely compressed material then becomes dispersed in a large volume of breccia formed in the expanding shock wave. An impact velocity of about 15 km/sec is consonant with the geology of Meteor Crater in light of the experimental equation of state of iron and inferred compressibility of the target rocks. The kinetic energy of the meteorite is estimated by scaling to have been from 1.4 to 1.7 megatons TNT equivalent.

  1. Definitions of terms in meteor astronomy

    Science.gov (United States)

    Koschny, Detlef; Borovicka, Jiri

    2017-10-01

    Over the last year, the IAU commission F1 (Meteors, Meteorites and Interplanetary Dust) has discussed and agreed a new definition of terminology related to our field of interest. It is available online at this link: https://www.iau.org/static/science/scientific_bodies/commissions/f1/meteordefinitions_approved.pdf. For your convenience it is reproduced here. Please keep these definitions in mind in any future communications about our topic.

  2. An ET Origin for Stratospheric Particles Collected during the 1998 Leonids Meteor Shower

    Science.gov (United States)

    Noever, David A.; Phillips, James A.; Horack, John M.; Jerman, Gregory; Myszka, Ed

    1999-01-01

    On 17 November 1998, a helium-filled weather balloon was launched into tfle strato- sphere, equipped with a xerogel microparticle collector. The three-hour flight was designed to sample the dust environment in the stratosphere during the Leonid meteor shower, and possibly to capture Leonid meteoroids. Environmental Scanning Election Microscope analyses of the returned collectors revealed the capture of a -30-pm particle. with a smooth, multigranular shape, and partially melted, translucent rims; similar to known Antarctic micrometeorites. Energy-dispersive X-ray Mass Spectroscopy shows en- riched concentrations of the non-volatile elements, Mg, Al, and Fe. The particle possesses a high magnesium to iron ratio of 2.96, similar to that observed in 1998 Leonids meteors (Borovicka, et al. 1999) and sharply higher than the ratio expected for typical material from the earth's crust. A statistical nearest-neighbor analysis of the abundance ratios Mg/Si, Al/Si, and Fe/Si demonstrates that the particle is most similar in composition to cosmic spherules captured during airplane flights throucrh the stratosphere. The mineralogical class is consistent with a stony (S) type of silicates. olivine [(Mg, Fe)2SiO4] and pyroxene [(Mg,Fe)SiO3]-or oxides, herecynite [(Fe,Mg) Al2O4]. Attribution to the debris stream of the Leonids' parent body, comet Tempel-Tuttle, would make it the first such material from beyond the orbit of Uranus positively identified on Earth.

  3. COnsortium of METabolomics Studies (COMETS)

    Science.gov (United States)

    The COnsortium of METabolomics Studies (COMETS) is an extramural-intramural partnership that promotes collaboration among prospective cohort studies that follow participants for a range of outcomes and perform metabolomic profiling of individuals.

  4. Meteor radar signal processing and error analysis

    Science.gov (United States)

    Kang, Chunmei

    Meteor wind radar systems are a powerful tool for study of the horizontal wind field in the mesosphere and lower thermosphere (MLT). While such systems have been operated for many years, virtually no literature has focused on radar system error analysis. The instrumental error may prevent scientists from getting correct conclusions on geophysical variability. The radar system instrumental error comes from different sources, including hardware, software, algorithms and etc. Radar signal processing plays an important role in radar system and advanced signal processing algorithms may dramatically reduce the radar system errors. In this dissertation, radar system error propagation is analyzed and several advanced signal processing algorithms are proposed to optimize the performance of radar system without increasing the instrument costs. The first part of this dissertation is the development of a time-frequency waveform detector, which is invariant to noise level and stable to a wide range of decay rates. This detector is proposed to discriminate the underdense meteor echoes from the background white Gaussian noise. The performance of this detector is examined using Monte Carlo simulations. The resulting probability of detection is shown to outperform the often used power and energy detectors for the same probability of false alarm. Secondly, estimators to determine the Doppler shift, the decay rate and direction of arrival (DOA) of meteors are proposed and evaluated. The performance of these estimators is compared with the analytically derived Cramer-Rao bound (CRB). The results show that the fast maximum likelihood (FML) estimator for determination of the Doppler shift and decay rate and the spatial spectral method for determination of the DOAs perform best among the estimators commonly used on other radar systems. For most cases, the mean square error (MSE) of the estimator meets the CRB above a 10dB SNR. Thus meteor echoes with an estimated SNR below 10dB are

  5. Multi-Year CMOR Observations of the Geminid Meteor Shower

    Science.gov (United States)

    Webster, A. R.; Jones, J.

    2011-01-01

    The three-station Canadian Meteor Orbit Radar (CMOR) is used here to examine the Geminid meteor shower with respect to variation in the stream properties including the flux and orbital elements over the period of activity in each of the consecutive years 2005 2008 and the variability from year to year. Attention is given to the appropriate choice and use of the D-criterion in the separating the shower meteors from the sporadic background.

  6. Double station observations of telescopic meteors in Mykolaiv

    Science.gov (United States)

    Kulichenko, M. O.; Shulga, O. V.; Sybiryakova, Ye. S.; Kozyryev, Ye. S.

    2017-02-01

    Meteor research using TV CCD unintensified techniques was started in 2011 in Nikolaev astronomical observatory (RI "NAO"). The method of meteor registration is based on the combined observation method developed at RI "NAO". The main accent of the research is made on the precise astrometry and meteoroid orbits calculation. In 2013 first double station meteors with low baseline were observed. Estimation of uncertainties of visible radiant equatorial coordinates, geocentric velocity and heliocentric meteoroid orbit parameters was carried out.

  7. The Science of Sungrazers, Sunskirters, and Other Near-Sun Comets

    Science.gov (United States)

    Jones, Geraint H.; Knight, Matthew M.; Battams, Karl; Boice, Daniel C.; Brown, John; Giordano, Silvio; Raymond, John; Snodgrass, Colin; Steckloff, Jordan K.; Weissman, Paul; Fitzsimmons, Alan; Lisse, Carey; Opitom, Cyrielle; Birkett, Kimberley S.; Bzowski, Maciej; Decock, Alice; Mann, Ingrid; Ramanjooloo, Yudish; McCauley, Patrick

    2018-02-01

    This review addresses our current understanding of comets that venture close to the Sun, and are hence exposed to much more extreme conditions than comets that are typically studied from Earth. The extreme solar heating and plasma environments that these objects encounter change many aspects of their behaviour, thus yielding valuable information on both the comets themselves that complements other data we have on primitive solar system bodies, as well as on the near-solar environment which they traverse. We propose clear definitions for these comets: We use the term near-Sun comets to encompass all objects that pass sunward of the perihelion distance of planet Mercury (0.307 AU). Sunskirters are defined as objects that pass within 33 solar radii of the Sun's centre, equal to half of Mercury's perihelion distance, and the commonly-used phrase sungrazers to be objects that reach perihelion within 3.45 solar radii, i.e. the fluid Roche limit. Finally, comets with orbits that intersect the solar photosphere are termed sundivers. We summarize past studies of these objects, as well as the instruments and facilities used to study them, including space-based platforms that have led to a recent revolution in the quantity and quality of relevant observations. Relevant comet populations are described, including the Kreutz, Marsden, Kracht, and Meyer groups, near-Sun asteroids, and a brief discussion of their origins. The importance of light curves and the clues they provide on cometary composition are emphasized, together with what information has been gleaned about nucleus parameters, including the sizes and masses of objects and their families, and their tensile strengths. The physical processes occurring at these objects are considered in some detail, including the disruption of nuclei, sublimation, and ionisation, and we consider the mass, momentum, and energy loss of comets in the corona and those that venture to lower altitudes. The different components of comae and

  8. Deep Interior: The first comprehensive geophysical investigation of an asteroid

    Science.gov (United States)

    Asphaug, E.; Belton, M.; Klaasen, K.; McFadden, L.; Ostro, S.; Safaeinili, A.; Scheeres, D.; Sunshine, J.; Yeomans, D.

    Near-Earth Objects (NEOs) come closer to Earth than any other celestial body, and their compositions are represented on Earth by thousands of well-studied meteorites. Yet we understand neither their origin, evolution, nor their geophysical behavior. These secrets are locked up in their unexplored interiors. Goal 1 of the NASA Strategic Plan emphasizes the requirement to catalogue and understand NEOs down to 1 km diameter. Goal 4 urges us to understand natural processes at work in the low gravity environment. Goal 5 expresses the need to explore the solar system and to learn how planets originated and evolved. In response to the NASA Strategic Plan we are proposing a NASA Discovery mission whose primary science objective is to greatly advance the realization of these Goals by conducting the first investigation of the global geophysics of an asteroid. Radio reflection data from 5 km orbit about a 1 km NEO will provide a tomographic 3D image of electromagnetic properties. Mechanical properties will be examined in the simplest possible way, using explosions to initiate seismic cratering events and to expose diverse interior units for spectroscopic analysis. Deep Interior is the lowest-risk, lowest cost path towards attaining the required characterization of NEOs. It breaks new ground for future missions to asteroids and comets and facilitates the design of reliable NEO technologies. Our science goals are as follows, and the techniques (radio science, imaging, IR spectroscopy, active surface science) will be described at this meeting: Asteroid Interiors. Radio, gravity, and seismology experiments give a complete first picture of an asteroid's deep interior, resolving inclusions, voids and unit boundaries at ˜ 30 m scales, and determining global and regional mechanical properties. Surface Geophysics. Blast experiments explore the structure and mechanics of the upper meters, demonstrate microgravity cratering, trigger natural geomorphic events, and expose subsurface

  9. Spectral properties of binary asteroids

    Science.gov (United States)

    Pajuelo, Myriam; Birlan, Mirel; Carry, Benoît; DeMeo, Francesca E.; Binzel, Richard P.; Berthier, Jérôme

    2018-04-01

    We present the first attempt to characterize the distribution of taxonomic class among the population of binary asteroids (15% of all small asteroids). For that, an analysis of 0.8-2.5{μ m} near-infrared spectra obtained with the SpeX instrument on the NASA/IRTF is presented. Taxonomic class and meteorite analog is determined for each target, increasing the sample of binary asteroids with known taxonomy by 21%. Most binary systems are bound in the S-, X-, and C- classes, followed by Q and V-types. The rate of binary systems in each taxonomic class agrees within uncertainty with the background population of small near-Earth objects and inner main belt asteroids, but for the C-types which are under-represented among binaries.

  10. 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...

  11. Identification of asteroid dynamical families

    Science.gov (United States)

    Valsecchi, G. B.; Carusi, A.; Knezevic, Z.; Kresak, L.; Williams, J. G.

    1989-01-01

    Problems involved in the identification of asteroid dynamical families are discussed, and some methodological guidelines are presented. Asteroid family classifications are reviewed, and differences in the existing classifications are examined with special attention given to the effects of observational selection on the classification of family membership. The paper also discusses various theories of secular perturbations, including the classical linear theory, the theory of Williams (1969), and the higher order/degree theory of Yuasa (1973).

  12. Are Trojan collisional families a source for short-period comets?

    Science.gov (United States)

    Marzari, F.; Farinella, P.; Vanzani, V.

    1995-07-01

    We have investigated the dynamical evolution of fragments generated by the impact breakup of Trojan asteroids, in order to study the formation of collisional families in the Trojan clouds and to identify a possible genetic connection between these fragments and the population of short-period comets. Using a collisional model based on the results of high-velocity laboratory impact experiments and previously applied to main-belt asteroid families, we show that typical family-forming Trojan collisions eject a significant percentage (at least =~20%) of the resulting fragments onto unstable orbits. Numerical integrations of the orbits of such fictitious, unstable Trojan fragments show that soon they experience close encounters with Jupiter, and as a consequence they become undistinguishable from those of Jupiter-family comets (some of which are currently close to the 1:1 Jovian resonance), of comets undergoing temporary satellite captures by Jupiter (such as P/Shoemaker-Levy 9), and of objects with Jupiter-crossing or -approaching orbits (such as 944 Hidalgo, 2060 Chiron, 5145 Pholus and 3552 Don Quixote). A reliable assessment of the efficiency of the transfer process from the Trojan clouds into comet-type orbits and of its time dependence is difficult, owing in particular to the poorly known size distribution of Trojans. However, an order-of-magnitude estimate suggests that if the fragment flux from the Trojan clouds over the last =~10^6^yr has been close to the average one over the solar system's lifetime, then a few tens of the 160 known short-period comets might have been generated by Trojan collisions.

  13. I. T. - R. O. C. K. S. Comet Nuclei Sample Return Mission

    Science.gov (United States)

    Dalcher, N.

    2009-04-01

    samples will be performed by touch and go manoeuvres and a penetrator device [10]. Solar arrays are used as energy source and additional cooling is required to keep the samples at low temperatures (Lisse C., Schultz P., Meech K. J., Delamere W. A. Icarus 187,4-15 (2007). [4] Simon S.B., Joswiak D.J., Ishii H.A., Bradley J.P., Chi M., Grossman L., Aléon J., Brownlee D.E., Fallon S., Hutcheon I.D., Matrajt G., Mckeegan K.D.: Refractory Inclusion Returned by Stardust from Comet P81/Wild 2. Meteoritics and Planetary Science (2007). [5] George D. Cody, Harald Ade, Conel M. O'D. Alexander, Tohru Araki, Anna Butterworth, Holger Fleckenstein, George Flynn, Mary K. Gilles, Chris Jacobsen, A.L. D. Kilcoyne, Keiko Messenger, Scott A. Sandford, Tolek Tyliszczak, Andrew J.Westphal4, Susan Wirick, and Hikaru Yabuta. Quantitative Organic and Light Element analysis of Comet 81P/Wild 2 particles using C-, N-, and O- µ-XANES, Meteoretics and Planetary Science: In Press. [6] Stern, S. et al. Alice: The Rosetta Ultraviolet Imaging Spectrograph. Space Science Reviews 128, 507-527 (2007). [7] Balsiger, H. et al. Rosina-Rosetta Orbiter Spectrometer for Ion and Neutral Analysis. Space Science Reviews 128, 745-801 (2007). [8] Colangeli, L. et al. The Grain Impact Analyser and Dust Accumulator (GIADA) Experiment for the Rosetta Mission: Design, Performances and First Results. Space Science Reviews 128, 803-821 (2007). [9] Yoshimitsu, T., Kubota, T., Nakatani, I., Adachi, T. & Saito, H. Micro-hopping robot for asteroid exploration. Acta Astronautica 52, 441-446 (2003). [10] Lorenz, R. et al. Demonstration of comet sample collection by penetrator. ESA SP-542, 387-393 (2003). [11] Küppers et al. Triple F—a comet nucleus sample return mission. Experimental Astronomy, Online First (2008).

  14. Tabulation of comet observations.

    Science.gov (United States)

    1993-04-01

    Concerning comets: 1980 IV Černis-Petrauskas, 1985 XVII Hartley-Good, 1985 XIII P/Giacobini-Zinner, 1985 XIX Thiele, 1986 III P/Halley, 1988 I Ichimura, 1988 V Liller, 1988 XV Machholz, 1989 X P/Brorsen-Metcalf, 1989 XIX Okazaki-Levy-Rudenko, 1989 XXII Aarseth-Brewington, 1990 V Austin, 1990 XVII Tsuchiya-Kiuchi, 1990 XX Levy, 1991 I P/Metcalf-Brewington, 1991 XXIV Shoemaker-Levy, 1991l Helin-Lawrence, 1991a1 Shoemaker-Levy, 1991g1 Zanotta-Brewington, 1991h1 Mueller, 1992d Tanaka-Machholz, 1992h Spacewatch, 1992l P/Giclas, 1992m P/Wolf, 1992n P/Faye, 1992p P/Brewington, 1992q Helin-Lawrence, 1992s P/Ciffréo, 1992t P/Swift-Tuttle, 1992u P/Väisälä, 1992x P/Schaumasse, 1992y Shoemaker, 1992a1 Ohshita, 1993a Mueller, 1993d Mueller, 1993e P/Shoemaker-Levy 9, P/Encke, P/Schwassmann-Wachmann 1.

  15. Special issue on asteroids - Introduction

    Science.gov (United States)

    Novaković, Bojan; Hsieh, Henry H.; Gronchi, Giovanni F.

    2018-04-01

    The articles in this special issue are devoted to asteroids, small solar system bodies that primarily populate a region between the orbits of Mars and Jupiter, known as the asteroid belt, but can also be found throughout the Solar System. Asteroids are considered to be a key to understanding the formation and evolution of our planetary system. Their properties allow us to test current theoretical models and develop new theoretical concepts pertaining to evolutionary processes in the Solar System. There have been major advances in asteroid science in the last decade, and that trend continues. Eighteen papers accepted for this special issue cover a wide range of asteroid-related subjects, pushing the boundaries of our understanding of these intriguing objects even further. Here we provide the reader with a brief overview of these thrilling papers, with an invitation for interested scientists to read each work in detail for a better understanding of these recent cutting edge results. As many topics in asteroid science remain open challenges, we hope that this special issue will be an important reference point for future research on this compelling topic.

  16. Asteroids Shedding Meteoroids...or Becoming Bolides (Invited)

    Science.gov (United States)

    Chapman, C. R.

    2009-12-01

    Historically, the study of asteroids has been separate from meteor science because of an observational gap: meteoroids larger than a few meters in size strike the Earth very rarely, and telescopic observations generally are of bodies tens of meters in size or larger. But bolide observations (from both Earth and space) are becoming more synoptic and telescopic searches will soon push down to ever smaller Near-Earth Objects (NEOs). So, instead of a gap between NEOs and meteoroids, there is now overlap. Already, last year, there was the first-ever discovery of an NEO that was predicted to - and did - strike Earth’s atmosphere, just 20 hours later. Before atmospheric entry, 2008 TC3 was well characterized for physical properties by telescopic observation. Despite ground-zero being very remote, observations were made of the atmospheric entry and explosion, and hundreds of rare ureilite meteorites were recovered during ensuing months. It is not widely appreciated that prospects are excellent that the Catalina Sky Survey (and other existing and proposed telescopic search programs) should detect a significant fraction of asteroids/meteoroids > 1 m diameter on their final plunge to Earth, providing hours to days of advance notice so that the NEO can be characterized telecopically, so that the bolide can be observed, and so that associated meteorites can be recovered. An NEO hazard issue concerns the smallest body that is dangerous. The 2003 SDT study considered that bodies impact in Carancas, Peru, shows that metallic meteoroids (which are a few percent of the total) are not the only ones that can strike the ground at hypervelocity. Furthermore, even if nothing more than a rain of meteorites were expected, a prudent public official could well respond to advanced warning of an impact at a specific time and place, even for a meteoroid just a few meters across, by advising people to stay indoors. Is any size truly safe? What is the smallest meteoroid meriting evacuation? Are

  17. The mass disruption of Oort cloud comets.

    Science.gov (United States)

    Levison, Harold F; Morbidelli, Alessandro; Dones, Luke; Jedicke, Robert; Wiegert, Paul A; Bottke, William F

    2002-06-21

    We have calculated the number of dormant, nearly isotropic Oort cloud comets in the solar system by (i) combining orbital distribution models with statistical models of dormant comet discoveries by well-defined surveys and (ii) comparing the model results to observations of a population of dormant comets. Dynamical models that assume that comets are not destroyed predict that we should have discovered approximately 100 times more dormant nearly isotropic comets than are actually seen. Thus, as comets evolve inward from the Oort cloud, the majority of them must physically disrupt.

  18. A Global Model of Meteoric Sodium

    Science.gov (United States)

    Marsh, Daniel R.; Janches, Diego; Feng, Wuhu; Plane, John M. C.

    2013-01-01

    A global model of sodium in the mesosphere and lower thermosphere has been developed within the framework of the National Center for Atmospheric Research's Whole Atmosphere Community Climate Model (WACCM). The standard fully interactive WACCM chemistry module has been augmented with a chemistry scheme that includes nine neutral and ionized sodium species. Meteoric ablation provides the source of sodium in the model and is represented as a combination of a meteoroid input function (MIF) and a parameterized ablation model. The MIF provides the seasonally and latitudinally varying meteoric flux which is modeled taking into consideration the astronomical origins of sporadic meteors and considers variations in particle entry angle, velocity, mass, and the differential ablation of the chemical constituents. WACCM simulations show large variations in the sodium constituents over time scales from days to months. Seasonality of sodium constituents is strongly affected by variations in the MIF and transport via the mean meridional wind. In particular, the summer to winter hemisphere flow leads to the highest sodium species concentrations and loss rates occurring over the winter pole. In the Northern Hemisphere, this winter maximum can be dramatically affected by stratospheric sudden warmings. Simulations of the January 2009 major warming event show that it caused a short-term decrease in the sodium column over the polar cap that was followed by a factor of 3 increase in the following weeks. Overall, the modeled distribution of atomic sodium in WACCM agrees well with both ground-based and satellite observations. Given the strong sensitivity of the sodium layer to dynamical motions, reproducing its variability provides a stringent test of global models and should help to constrain key atmospheric variables in this poorly sampled region of the atmosphere.

  19. Lifetime of a spacecraft around a synchronous system of asteroids using a dipole model

    Science.gov (United States)

    dos Santos, Leonardo Barbosa Torres; de Almeida Prado, Antonio F. Bertachini; Sanchez, Diogo Merguizo

    2017-11-01

    Space missions allow us to expand our knowledge about the origin of the solar system. It is believed that asteroids and comets preserve the physical characteristics from the time that the solar system was created. For this reason, there was an increase of missions to asteroids in the past few years. To send spacecraft to asteroids or comets is challenging, since these objects have their own characteristics in several aspects, such as size, shape, physical properties, etc., which are often only discovered after the approach and even after the landing of the spacecraft. These missions must be developed with sufficient flexibility to adjust to these parameters, which are better determined only when the spacecraft reaches the system. Therefore, conducting a dynamic investigation of a spacecraft around a multiple asteroid system offers an extremely rich environment. Extracting accurate information through analytical approaches is quite challenging and requires a significant number of restrictive assumptions. For this reason, a numerical approach to the dynamics of a spacecraft in the vicinity of a binary asteroid system is offered in this paper. In the present work, the equations of the Restricted Synchronous Four-Body Problem (RSFBP) are used to model a binary asteroid system. The main objective of this work is to construct grids of initial conditions, which relates semi-major axis and eccentricity, in order to quantify the lifetime of a spacecraft when released close to the less massive body of the binary system (modeled as a rotating mass dipole). We performed an analysis of the lifetime of the spacecraft considering several mass ratios of a binary system of asteroids and investigating the behavior of a spacecraft in the vicinity of this system. We analyze direct and retrograde orbits. This study investigated orbits that survive for at least 500 orbital periods of the system (which is approximately one year), then not colliding or escaping from the system during this

  20. (Not yet) Dead Comets in the Near-Earth Object Population

    Science.gov (United States)

    Mommert, Michael; Trilling, David; Mueller, Michael; Hora, Joseph; McMillan, Robert; Reach, William; Emery, Josh; Harris, Alan; Smith, Howard

    2013-10-01

    Near-Earth objects (NEOs) are replenished from a number of source regions in the asteroid main belt, but also from the comets. Most of the objects of cometary origin in the NEOs have ceased their activity, making these 'dead comets' nearly indistinguishable from low-albedo asteroids. Knowledge of the fraction of cometary NEOs is important to constrain the amount of cometary, carbonaceous material that has been brought to the Earth. We propose to observe 9 NEOs that are likely to be dead comets, for which we will derive diameters and albedos using thermal modeling. The measurement of the albedo provides evidence for a possibly cometary nature. The results of this project will contribute to constraining the fraction of NEOs that are of cometary origin. Furthermore, it will help investigating a possible relationship between dynamical properties and the albedo. In addition, high dynamic range (HDR) observations of 3 of our sample targets will be used to search for cometary activity in these objects. This method has been successful in NEO (3552) Don Quixote, where it revealed activity driven by CO2 gas. Our observations will be supported by ground-based optical observations that will improve the accuracy of the albedo measurements and perform an independent search for activity.

  1. Tying Extinction Events to Comet Impacts Large Enough to Cause an Extinction in Themselves.

    Science.gov (United States)

    Burgener, J. A.

    2017-12-01

    Comets over 35 km in size impacting Earth will create vast fireballs, and will boil large parts of the oceans, causing extinction events in themselves. They will likely provide enough energy to shatter the crust and eject large masses of molten rock from the mantle, forming traps. Traps are clearly associated with extinction events, but are not expected to cause extinctions. While Chicxulub is recognized to have occurred at the time of the K/Pg boundary layer, it is recognized as being too small in itself to cause an extinction. Are large comet impacts likely? The Kuiper belt has more than 100,000 objects over 100 km in diameter and millions over 10 km. Typically their orbits are less stable than asteroid orbits due to large bodies such as Pluto moving through the belt. The asteroid belt has only 10,000 objects over 10 km diameter. Comet impacts should be more common than asteroid impacts, yet none of the recognized craters are expected to be due to comets. There are many features on Earth that are poorly explained by Plate Tectonics that would be well explained if they were considered to be comet impact craters. A consideration of the Black Sea and the Tarim Basin will show that impact interpretations are a better fit than the present Plate Tectonics' explanations. Both basins are in the midst of mountain building from plate collisions, but are themselves not being disturbed by the plate collisions. Both are ellipses angled at 23.4 degrees to the equator, matching the angle expected for a low angle impact from a comet traveling in the ecliptic. Both are too deep at 15 km depths to be standard oceans (typically 5 km deep). Both are filled with horizontal layers of sediments, undisturbed by the mountain building occurring at the edges. Both have thin crusts and high Moho boundaries. Both have thin lithosphere. Yet both show GPS movement of the land around them moving away from them, as though they were much thicker and stronger than the surrounding land. The Tarim

  2. Radar meteors range distribution model. IV. Ionization coefficient

    Czech Academy of Sciences Publication Activity Database

    Pecinová, Drahomíra; Pecina, Petr

    2008-01-01

    Roč. 38, č. 1 (2008), s. 12-20 ISSN 1335-1842 R&D Projects: GA ČR GA205/03/1405 Institutional research plan: CEZ:AV0Z10030501 Keywords : physics of meteors * radar meteors * range distribution Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics

  3. Meteoric Impact and Ion Density Calculation in the Nighttime ...

    Indian Academy of Sciences (India)

    Bhavin

    2013-11-08

    Nov 8, 2013 ... Pandya, B. M., and S. A. Haider (2012), Meteor impact perturbation in the lower ionosphere of Mars: MGS observations,. Planet. Space Sci., 63, 105-109, doi: 10.1016/j.pss.2011.09.013. Page 6. Pandya, B. M., and S. A. Haider (2012), Meteor impact perturbation in the lower ionosphere of Mars: MGS ...

  4. Goals, technique and equipment of meteor study in Russia

    Science.gov (United States)

    Kartashova, A.; Bagrov, A. V.; Bolgova, G. T.; Kruchkov, S. V.; Leonov, V. A.; Mazurov, V. A.

    2013-09-01

    Institute of Astronomy RAS is one of the science institutes in the Russian Federation providing systematic optical meteor observations and supervises several meteor groups in our country. The main tasks of our investigations are dedicated to study meteoroid nature as well as meteoroid streams and meteoroid population in the Solar System. In the XXI century we in Russia carry out the reconstruction of our meteor astronomy due to possibilities of new meteor observation equipment (more powerful than were used before as visual and photographic methods) had made possible to select more interesting goals. First of our task is investigation of meteoroid streams crossing the Earth's orbit, and character of meteoroid distributions along of them. The multi stations meteor monitoring from located in the both hemispheres of the Earth can help in this study. According to the analysis of the evolution of meteor orbits, the compact and long lived meteoroid streams consist mainly from large particles. The observation equipment (cheap TV-cameras) with low limiting magnitude we use for gathering observational data. On the other hand, the observations of weak meteors are needed for new meteor shower indication (or confirmation of known meteor shower). The more effective way to do it is comparison of individual meteor orbits parameters (then calculation of radiants of meteor showers). The observations of space debris (as the meteors with low velocity - less 11.2 km/s) can be taking up within this task. The combination of high sensitive TV-cameras WATEC and super-fast lenses COMPUTAR are widely used for meteor TV-monitoring. The TVsystems for round-year meteor observations are fixed and are permanently oriented to the zenith area (the patrol camera - PatrolCa). The mobile TV-cameras (MobileCa) are used for double station observations (if it is possible) and located not far from main cameras PatrolCa (20-30 km). The mobile TVcameras observe 90% of main PatrolCa cameras FOV at altitudes

  5. Modeling Meteor Flares for Spacecraft Safety

    Science.gov (United States)

    Ehlert, Steven

    2017-01-01

    NASA's Meteoroid Environment Office (MEO) is tasked with assisting spacecraft operators and engineers in quantifying the threat the meteoroid environment poses to their individual missions. A more complete understanding of the meteoroid environment for this application requires extensive observations. One manner by which the MEO observes meteors is with dedicated video camera systems that operate nightly. Connecting the observational data from these video cameras to the relevant physical properties of the ablating meteoroids, however, is subject to sizable observational and theoretical uncertainties. Arguably the most troublesome theoretical uncertainty in ablation is a model for the structure of meteoroids, as observations clearly show behaviors wholly inconsistent with meteoroids being homogeneous spheres. Further complicating the interpretation of the observations in the context of spacecraft risk is the ubiquitous process of fragmentation and the flares it can produce, which greatly muddles any attempts to estimating initial meteoroid masses. In this talk a method of estimating the mass distribution of fragments in flaring meteors using high resolution video observations will be dis- cussed. Such measurements provide an important step in better understanding of the structure and fragmentation process of the parent meteoroids producing these flares, which in turn may lead to better constraints on meteoroid masses and reduced uncertainties in spacecraft risk.

  6. Analysis Procedures for Two Station Television Meteors

    Science.gov (United States)

    Hawkes, R. L.; Mason, K. I.; Fleming, D. E. B.; Stultz, C. T.

    1993-01-01

    This paper describes techniques for trajectory, light curve and orbital analysis of image intensified television meteors recorded at two stations. It will be argued that simple partial screen reference star fitting is preferable to higher order whole screen fits, and that only modest improvements in accuracy result from additional reference stars. The coordinate transformations and triangulation procedures are expressed exclusively in vector-matrix format. A simulation program has been developed for estimation of probable errors in radiants, heights and speeds. Heights accurate to about 0.2 km can be obtained even with moderate (26 km) baselines. Because of the difficulty in defining a common fiducial point for the meteor head in different frames, velocities are usually in error by at least several percent. One technique for obtaining photometric measures from the digitized sequences will be described - accuracies of the order of +-0.20M can be obtained in a relative sense, with absolute accuracies no worse than double that value. The techniques are illustrated with actual two station data.

  7. First results on video meteors from Crete, Greece

    Science.gov (United States)

    Maravelias, G.

    2012-01-01

    This work presents the first systematic video meteor observations from a, forthcoming permanent, station in Crete, Greece, operating as the first official node within the International Meteor Organization's Video Network. It consists of a Watec 902 H2 Ultimate camera equipped with a Panasonic WV-LA1208 (focal length 12mm, f/0.8) lens running MetRec. The system operated for 42 nights during 2011 (August 19-December 30, 2011) recording 1905 meteors. It is significantly more performant than a previous system used by the author during the Perseids 2010 (DMK camera 21AF04.AS by The Imaging Source, CCTV lens of focal length 2.8 mm, UFO Capture v2.22), which operated for 17 nights (August 4-22, 2010) recording 32 meteors. Differences - according to the author's experience - between the two softwares (MetRec, UFO Capture) are discussed along with a small guide to video meteor hardware.

  8. Processing method and results of meteor shower radar observations

    International Nuclear Information System (INIS)

    Belkovich, O.I.; Suleimanov, N.I.; Tokhtasjev, V.S.

    1987-01-01

    Studies of meteor showers permit the solving of some principal problems of meteor astronomy: to obtain the structure of a stream in cross section and along its orbits; to retrace the evolution of particle orbits of the stream taking into account gravitational and nongravitational forces and to discover the orbital elements of its parent body; to find out the total mass of solid particles ejected from the parent body taking into account physical and chemical evolution of meteor bodies; and to use meteor streams as natural probes for investigation of the average characteristics of the meteor complex in the solar system. A simple and effective method of determining the flux density and mass exponent parameter was worked out. This method and its results are discussed

  9. Comet showers and Nemesis, the death star

    International Nuclear Information System (INIS)

    Hills, J.G.

    1984-01-01

    The recently proposed hypothesis that the periodic extinctions of terrestrial species are the result of comet showers catalyzed by a hypothetical distant solar companion, Nemesis, a tale of global death by comet bombardment of the earth, is discussed

  10. CATASTROPHIC DISRUPTION OF COMET ISON

    Energy Technology Data Exchange (ETDEWEB)

    Keane, Jacqueline V.; Kleyna, Jan T.; Riesen, Timm-Emmanuel; Meech, Karen J. [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Milam, Stefanie N.; Charnley, Steven B. [Astrochemistry Laboratory, NASA GSFC, MS 690, Greenbelt, MD 20771 (United States); Coulson, Iain M. [Joint Astronomy Center, 660 North Aohoku Place, Hilo, HI 96720 (United States); Sekanina, Zdenek [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Kracht, Rainer, E-mail: keane@ifa.hawaii.edu [Ostlandring 53, D-25335 Elmshorn, Schleswig-Holstein (Germany)

    2016-11-10

    We report submillimeter 450 and 850 μ m dust continuum observations for comet C/2012 S1 (ISON) obtained at heliocentric distances 0.31–0.08 au prior to perihelion on 2013 November 28 ( r {sub h} = 0.0125 au). These observations reveal a rapidly varying dust environment in which the dust emission was initially point-like. As ISON approached perihelion, the continuum emission became an elongated dust column spread out over as much as 60″ (>10{sup 5} km) in the anti-solar direction. Deconvolution of the November 28.04 850 μ m image reveals numerous distinct clumps consistent with the catastrophic disruption of comet ISON, producing ∼5.2 × 10{sup 10} kg of submillimeter-sized dust. Orbital computations suggest that the SCUBA-2 emission peak coincides with the comet's residual nucleus.

  11. Catastrophic Disruption of Comet ISON

    Science.gov (United States)

    Keane, Jacqueline V.; Milam, Stefanie N.; Coulson, Iain M.; Kleyna, Jan T.; Sekanina, Zdenek; Kracht, Rainer; Riesen, Timm-Emmanuel; Meech, Karen J.; Charnley, Steven B.

    2016-01-01

    We report submillimeter 450 and 850 microns dust continuum observations for comet C/2012 S1 (ISON) obtained at heliocentric distances 0.31-0.08 au prior to perihelion on 2013 November 28 (rh?=?0.0125 au). These observations reveal a rapidly varying dust environment in which the dust emission was initially point-like. As ISON approached perihelion, the continuum emission became an elongated dust column spread out over as much as 60? (greater than 10(exp 5) km in the anti-solar direction. Deconvolution of the November 28.04 850 microns image reveals numerous distinct clumps consistent with the catastrophic disruption of comet ISON, producing approximately 5.2?×?10(exp 10) kg of submillimeter-sized dust. Orbital computations suggest that the SCUBA-2 emission peak coincides with the comet's residual nucleus.

  12. Hummingbird Comet Nucleus Analysis Mission

    Science.gov (United States)

    Kojiro, Daniel; Carle, Glenn C.; Lasher, Larry E.

    2000-01-01

    Hummingbird is a highly focused scientific mission, proposed to NASA s Discovery Program, designed to address the highest priority questions in cometary science-that of the chemical composition of the cometary nucleus. After rendezvous with the comet, Hummingbird would first methodically image and map the comet, then collect and analyze dust, ice and gases from the cometary atmosphere to enrich characterization of the comet and support landing site selection. Then, like its namesake, Hummingbird would carefully descend to a pre-selected surface site obtaining a high-resolution image, gather a surface material sample, acquire surface temperature and then immediately return to orbit for detailed chemical and elemental analyses followed by a high resolution post-sampling image of the site. Hummingbird s analytical laboratory contains instrumentation for a comprehensive molecular and elemental analysis of the cometary nucleus as well as an innovative surface sample acquisition device.

  13. CO2 Orbital Trends in Comets

    Science.gov (United States)

    Kelley, Michael; Feaga, Lori; Bodewits, Dennis; McKay, Adam; Snodgrass, Colin; Wooden, Diane

    2014-12-01

    Spacecraft missions to comets return a treasure trove of details of their targets, e.g., the Rosetta mission to comet 67P/Churyumov-Gerasimenko, the Deep Impact experiment at comet 9P/Tempel 1, or even the flyby of C/2013 A1 (Siding Spring) at Mars. Yet, missions are rare, the diversity of comets is large, few comets are easily accessible, and comet flybys essentially return snapshots of their target nuclei. Thus, telescopic observations are necessary to place the mission data within the context of each comet's long-term behavior, and to further connect mission results to the comet population as a whole. We propose a large Cycle 11 project to study the long-term activity of past and potential future mission targets, and select bright Oort cloud comets to infer comet nucleus properties, which would otherwise require flyby missions. In the classical comet model, cometary mass loss is driven by the sublimation of water ice. However, recent discoveries suggest that the more volatile CO and CO2 ices are the likely drivers of some comet active regions. Surprisingly, CO2 drove most of the activity of comet Hartley 2 at only 1 AU from the Sun where vigorous water ice sublimation would be expected to dominate. Currently, little is known about the role of CO2 in comet activity because telluric absorptions prohibit monitoring from the ground. In our Cycle 11 project, we will study the CO2 activity of our targets through IRAC photometry. In conjunction with prior observations of CO2 and CO, as well as future data sets (JWST) and ongoing Earth-based projects led by members of our team, we will investigate both long-term activity trends in our target comets, with a particular goal to ascertain the connections between each comet's coma and nucleus.

  14. Developing an Asteroid Rotational Theory

    Science.gov (United States)

    Geis, Gena; Williams, Miguel; Linder, Tyler; Pakey, Donald

    2018-01-01

    The goal of this project is to develop a theoretical asteroid rotational theory from first principles. Starting at first principles provides a firm foundation for computer simulations which can be used to analyze multiple variables at once such as size, rotation period, tensile strength, and density. The initial theory will be presented along with early models of applying the theory to the asteroid population. Early results confirm previous work by Pravec et al. (2002) that show the majority of the asteroids larger than 200m have negligible tensile strength and have spin rates close to their critical breakup point. Additionally, results show that an object with zero tensile strength has a maximum rotational rate determined by the object’s density, not size. Therefore, an iron asteroid with a density of 8000 kg/m^3 would have a minimum spin period of 1.16h if the only forces were gravitational and centrifugal. The short-term goal is to include material forces in the simulations to determine what tensile strength will allow the high spin rates of asteroids smaller than 150m.

  15. ASTEROID POLARIMETRIC DATABASE V6.0

    Data.gov (United States)

    National Aeronautics and Space Administration — The Asteroid Polarimetric Database (APD) is a collection of asteroid polarimetry results compiled by D.F. Lupishko and S.V. Vasiliev of Karazin Kharkiv National...

  16. ASTEROID PHOTOMETRIC CATALOG V1.0

    Data.gov (United States)

    National Aeronautics and Space Administration — The Asteroid Photometric Catalog (3rd update), Lagerkvist, et.al., 1993 [LAGERKVISTETAL1993], is a compilation of all asteroid lightcurve photometry published up to...

  17. ASTEROID RADAR V18.0

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set is intended to include all published groundbased asteroid radar detections. The file is based on the collection of asteroid radar detections...

  18. ASTEROID RADAR V17.0

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set is intended to include all published groundbased asteroid radar detections. The file is based on the collection of asteroid radar detections...

  19. ASTEROID RADAR V15.0

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set is intended to include all published groundbased asteroid radar detections. The file is based on the collection of asteroid radar detections...

  20. ASTEROID FAMILY IDENTIFICATIONS V1.0

    Data.gov (United States)

    National Aeronautics and Space Administration — This is a compilation of the family memberships of numbered asteroids in five different asteroid family analyses. These include the analyses of Zappala et al.,...

  1. ASTEROID RADAR V16.0

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set is intended to include all published groundbased asteroid radar detections. The file is based on the collection of asteroid radar detections...

  2. The small binary asteroid (939) Isberga

    Czech Academy of Sciences Publication Activity Database

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

    2015-01-01

    Roč. 248, March (2015), s. 516-525 ISSN 0019-1035 Institutional support: RVO:67985815 Keywords : asteroids * dynamics * satellites of asteroids Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 3.383, year: 2015

  3. ASTEROID POLARIMETRIC DATABASE V7.0

    Data.gov (United States)

    National Aeronautics and Space Administration — The Asteroid Polarimetric Database (APD) is a collection of asteroid polarimetry results compiled by D.F. Lupishko and S.V. Vasiliev of Karazin Kharkiv National...

  4. ASTEROID POLARIMETRIC DATABASE V8.0

    Data.gov (United States)

    National Aeronautics and Space Administration — The Asteroid Polarimetric Database (APD) is a collection of asteroid polarimetry results compiled by D.F. Lupishko of Karazin Kharkiv National University, Ukraine....

  5. ASTEROID POLARIMETRIC DATABASE V5.0

    Data.gov (United States)

    National Aeronautics and Space Administration — The Asteroid Polarimetric Database (APD) is a collection of asteroid polarimetry results compiled by D.F. Lupishko of Karazin Kharkiv National University, Ukraine....

  6. BELSKAYA ASTEROID POLARIMETRY V1.0

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set contains UBVRI polarimetric measurements of ten main belt asteroids and one potentially hazardous near-Earth asteroid (NEA), from Belskaya et al....

  7. ASTEROID PHOTOMETRIC CATALOG V1.1

    Data.gov (United States)

    National Aeronautics and Space Administration — The Asteroid Photometric Catalog (3rd update), Lagerkvist, et.al., 1993 [LAGERKVISTETAL1993], is a compilation of all asteroid lightcurve photometry published up to...

  8. Infrared techniques for comet observations

    Science.gov (United States)

    Hanner, Martha S.; Tokunaga, Alan T.

    1991-01-01

    The infrared spectral region (1-1000 microns) is important for studies of both molecules and solid grains in comets. Infrared astronomy is in the midst of a technological revolution, with the development of sensitive 2D arrays leading to IR cameras and spectrometers with vastly improved sensitivity and resolution. The Halley campaign gave us tantalizing first glimpses of the comet science possible with this new technology, evidenced, for example, by the many new spectral features detected in the infrared. The techniques of photometry, imaging, and spectroscopy are reviewed in this chapter and their status at the time of the Halley observations is described.

  9. Impacts into porous asteroids

    Science.gov (United States)

    Housen, Kevin R.; Sweet, William J.; Holsapple, Keith A.

    2018-01-01

    Many small bodies in the solar system have bulk density well below the solid density of the constituent mineral grains in their meteorite counterparts. Those low-density bodies undoubtedly have significant porosity, which is a key factor that affects the formation of impact craters. This paper summarizes the results of lab experiments in which materials with porosity ranging from 43% to 96% were impacted at ∼1800 m/s. The experiments were performed on a geotechnical centrifuge, in order to reproduce the lithostatic overburden stress and ejecta ballistics that occur in large-scale cratering events on asteroids or planetary satellites. Experiments performed at various accelerations, up to 514G, simulate the outcomes of impacts at size scales up to several tens of km in diameter. Our experiments show that an impact into a highly porous cohesionless material generates a large ovoid-shaped cavity, due to crushing by the outgoing shock. The cavity opens up to form a transient crater that grows until the material flow is arrested by gravity. The cavity then collapses to form the final crater. During collapse, finely crushed material that lines the cavity wall is carried down and collected in a localized region below the final crater floor. At large simulated sizes (high accelerations), most of the crater volume is formed by compaction, because growth of the transient crater is quickly arrested. Nearly all ejected material falls back into the crater, leaving the crater without an ejecta blanket. We find that such compaction cratering and suppression of the ejecta blankets occur for large craters on porous bodies when the ratio of the lithostatic stress at one crater depth to the crush strength of the target exceeds ∼0.005. The results are used to identify small solar system bodies on which compaction cratering likely occurs. A model is developed that gives the crater size and ejecta mass that would result for a specified impact into a porous object.

  10. Split Active Asteroid P/2016 J1 (PANSTARRS)

    Science.gov (United States)

    Hui, Man-To; Jewitt, David; Du, Xinnan

    2017-10-01

    We present a photometric and astrometric study of the split active asteroid P/2016 J1 (PANSTARRS). Separation occurred either in 2012 May to June, or 2010 April, with a separation speed Vsep = 0.70 ± 0.02 m s-1 for the former scenario and 0.83 ± 0.06 m s-1 for the latter. The two fragments (hereafter J1-A and J1-B) have similar, Sun-like colors that are comparable to the colors of primitive C- and G-type asteroids. With a nominal comet-like albedo, pR = 0.04, the effective, dust-contaminated cross sections are estimated to be 2.4 km2 (J1-A) and 0.5 km2 (J1-B). We estimate that the nucleus radii lie in the range 140 ice became exposed at the surface, perhaps via a minor impact, and that sublimation torques then rapidly drove the body to breakup. Further disintegration events are anticipated owing to the rotational instability. Reference: Hui, M.-T., Jewitt, D. and Du, X., 2017. AJ, 153(4), p.141.

  11. ATLAS: Finding the Nearest Asteroids

    Science.gov (United States)

    Heinze, Aren; Tonry, John L.; Denneau, Larry; Stalder, Brian

    2017-10-01

    The Asteroid Terrestrial-impact Last Alert System (ATLAS) became fully operational in June 2017. Our two robotic, 0.5 meter telescopes survey the whole accessible sky every two nights from the Hawaiian mountains of Haleakala and Mauna Loa. With sensitivity to magnitude 19.5 over a field of 30 square degrees, we discover several bright near-Earth objects every month - particularly fast moving asteroids, which can slip by other surveys that scan the sky more slowly. Several important developments in 2017 have enhanced our sensitivity to small, nearby asteroids and potential impactors. We report on these developments - including optical adjustments, automated screening of detections, closer temporal spacing of images, and tolerance for large deviations from Great Circle motion on the sky - and we describe their effect in terms of measuring and discovering real objects.

  12. Comet Mineralogy as Inferred from Infrared Spectra of Comets

    Science.gov (United States)

    Wooden, Diane H.

    2006-01-01

    For most comets, infrared (IR) spectroscopy (remote sensing) is the method through which we diagnose the mineralogy and size distribution of dust in their comae. The shape and contrast of the IR spectral features depend on the particle size: optically active minerals (absorbing of visible and near-IR solar photons) and submicron solid grains or highly porous (> 90% vacuum) grains primarily contribute to the shapes of the observed resonances. Comet mineralogies typically are determined by fitting thermal emission models of ensembles of discrete mineral grains to observed IR spectral energy distributions. The absorptivities (Q-abs) and scattering efficiencies (Q-scat) of the discrete mineral grains are computed using Mie scattering, Maxwell-Garnet mixing, Discrete Dipole Approximation, and Multi-Layered Sphere codes. These techniques when applied to crystalline minerals, specifically olivine (Mg_x, Fe_1-x)2 Si04, x>0.9, require the use of ellipsoidal shaped particles with elongated axial ratios or hollow spheres to produce the shapes of the resonances observed both from comet comae and laboratory samples. The wavelength positions of the distinct resonances from submicron-radii crystalline silicates, as well as their thermal equilibrium temperatures, constrain the crystalline olivine to have a relatively high Mg-content (x>0.9, or Fo>90). Only resonances computed for submicron Mg-rich crystalline olivine and crystalline orthopyroxene match the observed IR spectral features. However, this has led to the interpretation that micron-radii and larger crystals are absent from comet comae. Furthermore, the mass fraction of silicate crystals is dependent upon whether just the submicron portion of the size distribution is being compared or the submicron crystals compare to the aggregates of porous amorphous silicates that are computationally tractable as porous spheres. We will discuss the Deep Impact results as examples of these challenges to interpreting mid-IR spectra of

  13. The MAGIC meteoric smoke particle sampler

    Science.gov (United States)

    Hedin, Jonas; Giovane, Frank; Waldemarsson, Tomas; Gumbel, Jörg; Blum, Jürgen; Stroud, Rhonda M.; Marlin, Layne; Moser, John; Siskind, David E.; Jansson, Kjell; Saunders, Russell W.; Summers, Michael E.; Reissaus, Philipp; Stegman, Jacek; Plane, John M. C.; Horányi, Mihály

    2014-10-01

    Between a few tons to several hundred tons of meteoric material enters the Earth's atmosphere each day, and most of this material is ablated and vaporized in the 70-120 km altitude region. The subsequent chemical conversion, re-condensation and coagulation of this evaporated material are thought to form nanometre sized meteoric smoke particles (MSPs). These smoke particles are then subject to further coagulation, sedimentation and global transport by the mesospheric circulation. MSPs have been proposed as a key player in the formation and evolution of ice particle layers around the mesopause region, i.e. noctilucent clouds (NLC) and polar mesosphere summer echoes (PMSE). MSPs have also been implicated in mesospheric heterogeneous chemistry to influence the mesospheric odd oxygen/odd hydrogen (Ox/HOx) chemistry, to play an important role in the mesospheric charge balance, and to be a significant component of stratospheric aerosol and enhance the depletion of O3. Despite their apparent importance, little is known about the properties of MSPs and none of the hypotheses can be verified without direct evidence of the existence, altitude and size distribution, shape and elemental composition. The aim of the MAGIC project (Mesospheric Aerosol - Genesis, Interaction and Composition) was to develop an instrument and analysis techniques to sample for the first time MSPs in the mesosphere and return them to the ground for detailed analysis in the laboratory. MAGIC meteoric smoke particle samplers have been flown on several sounding rocket payloads between 2005 and 2011. Several of these flights concerned non-summer mesosphere conditions when pure MSP populations can be expected. Other flights concerned high latitude summer conditions when MSPs are expected to be contained in ice particles in the upper mesosphere. In this paper we present the MAGIC project and describe the MAGIC MSP sampler, the measurement procedure and laboratory analysis. We also present the attempts to

  14. Reflectance spectroscopy and asteroid surface mineralogy

    International Nuclear Information System (INIS)

    Gaffey, M.J.; Bell, J.F.; Cruikshank, D.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. 100 refs

  15. System Concept for Remote Measurement of Asteroid Molecular Composition

    Science.gov (United States)

    Hughes, G. B.; Lubin, P. M.; Zhang, Q.; Brashears, T.; Cohen, A. N.; Madajian, J.

    2016-12-01

    We propose a method for probing the molecular composition of cold solar system targets (asteroids, comets, planets, moons) from a distant vantage, such as from a spacecraft orbiting the object. A directed energy beam is focused on the target. With sufficient flux, the spot temperature rises rapidly, and evaporation of surface materials occurs. The melted spot creates a high-temperature blackbody source, and ejected material creates a plume of surface materials in front of the spot. Molecular and atomic absorption of the blackbody radiation occurs within the ejected plume. Bulk composition of the surface material is investigated by using a spectrometer to view the heated spot through the ejected material. Our proposed method differs from technologies such as Laser-Induced Breakdown Spectroscopy (LIBS), which atomizes and ionizes materials in the target; scattered ions emit characteristic radiation, and the LIBS detector performs atomic composition analysis by observing emission spectra. Standoff distance for LIBS is limited by the strength of characteristic emission, and distances greater than 10 m are problematic. Our proposed method detects atomic and molecular absorption spectra in the plume; standoff distance is limited by the size of heated spot, and the plume opacity; distances on the order of tens of kilometers are immediately feasible. Simulations have been developed for laser heating of a rocky target, with concomitant evaporation. Evaporation rates lead to determination of plume density and opacity. Absorption profiles for selected materials are estimated from plume properties. Initial simulations of absorption profiles with laser heating show great promise for molecular composition analysis from tens of kilometers distance. This paper explores the feasibility a hypothetical mission that seeks to perform surface molecular composition analysis of a near-earth asteroid while the craft orbits the asteroid. Such a system has compelling potential benefit for

  16. Project RAMA: Reconstructing Asteroids Into Mechanical Automata

    Science.gov (United States)

    Dunn, Jason; Fagin, Max; Snyder, Michael; Joyce, Eric

    2017-01-01

    Many interesting ideas have been conceived for building space-based infrastructure in cislunar space. From O'Neill's space colonies, to solar power satellite farms, and even prospecting retrieved near earth asteroids. In all the scenarios, one thing remained fixed - the need for space resources at the outpost. To satisfy this need, O'Neill suggested an electromagnetic railgun to deliver resources from the lunar surface, while NASA's Asteroid Redirect Mission called for a solar electric tug to deliver asteroid materials from interplanetary space. At Made In Space, we propose an entirely new concept. One which is scalable, cost effective, and ensures that the abundant material wealth of the inner solar system becomes readily available to humankind in a nearly automated fashion. We propose the RAMA architecture, which turns asteroids into self-contained spacecraft capable of moving themselves back to cislunar space. The RAMA architecture is just as capable of transporting conventional-sized asteroids on the 10-meter length scale as transporting asteroids 100 meters or larger, making it the most versatile asteroid retrieval architecture in terms of retrieved-mass capability. This report describes the results of the Phase I study funded by the NASA NIAC program for Made In Space to establish the concept feasibility of using space manufacturing to convert asteroids into autonomous, mechanical spacecraft. Project RAMA, Reconstituting Asteroids into Mechanical Automata, is designed to leverage the future advances of additive manufacturing (AM), in-situ resource utilization (ISRU) and in-situ manufacturing (ISM) to realize enormous efficiencies in repeated asteroid redirect missions. A team of engineers at Made In Space performed the study work with consultation from the asteroid mining industry, academia, and NASA. Previous studies for asteroid retrieval have been constrained to studying only asteroids that are both large enough to be discovered, and small enough to be

  17. Deep Interior Mission: Imaging the Interior of Near-Earth Asteroids Using Radio Reflection Tomography

    Science.gov (United States)

    Safaeinili, A.; Asphaug, E.; Rodriquez, E.; Gurrola, E.; Belton, M.; Klaasen, K.; Ostro, S.; Plaut, J.; Yeomans, D.

    2005-01-01

    materials that we are likely to encounter, from undifferentiated to highly evolved. The 5-15 MHz radar is capable of probing more primitive bodies (e.g. comets or C-types) that may be available given other launch schedules. 5 MHz radar easily penetrates, with the required SNR , greater than 1 km of basalt (a good analog for Nyx). Basalt has a greater loss tangent than expected for most asteroids, although iron-rich M-types are probably not appropriate targets. 15 MHz radar penetrates the outer approximately 100 m of rocky 1 km asteroids and the deep interiors of comets. Laboratory studies of the most common NE0 materials expected (S-, C- and V-type meteorite analogs) will commence in 2005.

  18. METEOR v1.0 - A usage example

    International Nuclear Information System (INIS)

    Palomo, E.

    1994-01-01

    This script describes a detailed example of the use of the software package METEOR for statistical analysis of meteorological data series. A real spanish meteorological data set is chosen to show the capabilities of METEOR. Output files and resultant plots provided of their interpretations are compiled in three appendixes. The original version of METEOR have been developed by Ph. D.Elena Palomo, CIEMAT-IER, GIASE. It is built by linking programs and routines written in FORTRAN 77 and it adds the graphical capabilities of GNUPLOT. The shape of this toolbox was designed following the criteria of modularity, flexibility and agility criteria. All the input, output and analysis options are structured in three main menus: i) the first is aimed to evaluate the quality of the data set; ii) the second is aimed for pre-processing of the data; and iii) the third is aimed towards the statistical analyses and for creating the graphical outputs. Actually the information about METEOR is constituted by three documents written is spanish: 1) METEOR v1.0: User's guide; 2) METEOR v1.0: A usage example; 3) METEOR v1 .0: Design and structure of the software package. (Author)

  19. Crowdsourcing, the great meteor storm of 1833, and the founding of meteor science.

    Science.gov (United States)

    Littmann, Mark; Suomela, Todd

    2014-06-01

    Yale science professor Denison Olmsted used crowdsourcing to gather observations from across the United States of the unexpected deluge of meteors on 13 November 1833--more than 72,000/h. He used these observations (and newspaper accounts and correspondence from scientists) to make a commendably accurate interpretation of the meteor storm, overturning 2100 years of erroneous teachings about shooting stars and establishing meteor science as a new branch of astronomy. Olmsted's success was substantially based on his use of newspapers and their practice of news pooling to solicit observations from throughout the country by lay and expert observers professionally unaffiliated with Yale College and him. In today's parlance, Olmsted was a remarkably successful early practitioner of scientific crowdsourcing, also known as citizen science. He may have been the first to use mass media for crowdsourcing in science. He pioneered many of the citizen-science crowdsourcing practices that are still in use today: an open call for citizen participation, a clearly defined task, a large geographical distribution for gathering data and a rapid response to opportunistic events. Olmsted's achievement is not just that he used crowdsourcing in 1833 but that crowdsourcing helped him to advance science significantly. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. The COMET Sleep Research Platform.

    Science.gov (United States)

    Nichols, Deborah A; DeSalvo, Steven; Miller, Richard A; Jónsson, Darrell; Griffin, Kara S; Hyde, Pamela R; Walsh, James K; Kushida, Clete A

    2014-01-01

    The Comparative Outcomes Management with Electronic Data Technology (COMET) platform is extensible and designed for facilitating multicenter electronic clinical research. Our research goals were the following: (1) to conduct a comparative effectiveness trial (CET) for two obstructive sleep apnea treatments-positive airway pressure versus oral appliance therapy; and (2) to establish a new electronic network infrastructure that would support this study and other clinical research studies. The COMET platform was created to satisfy the needs of CET with a focus on creating a platform that provides comprehensive toolsets, multisite collaboration, and end-to-end data management. The platform also provides medical researchers the ability to visualize and interpret data using business intelligence (BI) tools. COMET is a research platform that is scalable and extensible, and which, in a future version, can accommodate big data sets and enable efficient and effective research across multiple studies and medical specialties. The COMET platform components were designed for an eventual move to a cloud computing infrastructure that enhances sustainability, overall cost effectiveness, and return on investment.

  1. Comet C/2001 J1

    Czech Academy of Sciences Publication Activity Database

    Pravec, Petr; Helin, E.; Lawrence, K.; Kotková, Lenka; Tichá, J.; Tichý, M.

    č. 7623 (2001), s. 1 ISSN 0081-0304 R&D Projects: GA ČR GA205/99/0255 Institutional research plan: CEZ:AV0Z1003909 Keywords : comets * astrometry Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics

  2. MEST-Do the ``rubble-pile'' asteroid-1950 DA, with low 1700 kg/m3 density, has a structure with spacetime center?

    Science.gov (United States)

    Cao, Dayong

    2015-04-01

    According to Einstein's equation and observation of flat universe, the paper gives new ideas both of dark massenergy and spacetime center, and supporses that some asteroids were comets which have spacetime center, and some comets were wraped up by rock in 2012. It explains of a observation about low density of the asteroid-1950 DA by spacetime center of the asteroid. (see Ben Rozitis, ``Cohesive forces prevent the rotational breakup of rubble-pile asteroid (29075) 1950 DA,'' http://www. nature.com / nature / journal / v512 / n7513/full/nature13632.html) It also can explain of a rock hull of 67P/Churyumov-Gerasimenko. (see Jonathan O'Callaghan, ``Comets are like deep fried ICE CREAM: Nasa ice-box experiment confirms 67P is hard on the outside but fluffy on the inside,'' http://www.dailymail.co.uk/sciencetech/article-2949020/Comets-like-deep-fried-ICE-CREAM-Nasa-ice-box-experiment-confirms-67P-hard-outside-fluffy-inside.html) (See Dayong Cao, ``MEST-The dark hole, dark comet and dark matter are the space-time center'' and ``MEST- avoid next extinction by a space-time effect'') http://meetings.aps.org/link/BAPS.2014.APR.L1.3 http://meetings.aps.org/link/BAPS.2014.APR.L1.2 http://meetings.aps.org/link/BAPS.2015.APR.L1.2 http://meeting.aps.org/Meeting/CAL12/Session/H1.8 http://meetings.aps.org/link/BAPS.2012.APR.K1.79

  3. Asteroids 87887-415992: the youngest known asteroid pair?

    Czech Academy of Sciences Publication Activity Database

    Žižka, J.; Galád, A.; Vokrouhlický, D.; Pravec, Petr; Kušnirák, Peter; Hornoch, Kamil

    2016-01-01

    Roč. 595, November (2016), A20/1-A20/11 ISSN 0004-6361 R&D Projects: GA ČR GAP209/12/0229 Institutional support: RVO:67985815 Keywords : celestial mechanics * minor planets * asteroids Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 4.378, year: 2014

  4. Comets as Messengers from the Early Solar System - Emerging Insights on Delivery of Water, Nitriles, and Organics to Earth

    Science.gov (United States)

    Mumma, Michael J.; Charnley, Steven B.

    2012-01-01

    The question of exogenous delivery of water and organics to Earth and other young planets is of critical importance for understanding the origin of Earth's volatiles, and for assessing the possible existence of exo-planets similar to Earth. Viewed from a cosmic perspective, Earth is a dry planet, yet its oceans are enriched in deuterium by a large factor relative to nebular hydrogen and analogous isotopic enrichments in atmospheric nitrogen and noble gases are also seen. Why is this so? What are the implications for Mars? For icy Worlds in our Planetary System? For the existence of Earth-like exoplanets? An exogenous (vs. outgassed) origin for Earth's atmosphere is implied, and intense debate on the relative contributions of comets and asteroids continues - renewed by fresh models for dynamical transport in the protoplanetary disk, by revelations on the nature and diversity of volatile and rocky material within comets, and by the discovery of ocean-like water in a comet from the Kuiper Belt (cf., Mumma & Charnley 2011). Assessing the creation of conditions favorable to the emergence and sustenance of life depends critically on knowledge of the nature of the impacting bodies. Active comets have long been grouped according to their orbital properties, and this has proven useful for identifying the reservoir from which a given comet emerged (OC, KB) (Levison 1996). However, it is now clear that icy bodies were scattered into each reservoir from a range of nebular distances, and the comet populations in today's reservoirs thus share origins that are (in part) common. Comets from the Oort Cloud and Kuiper Disk reservoirs should have diverse composition, resulting from strong gradients in temperature and chemistry in the proto-planetary disk, coupled with dynamical models of early radial transport and mixing with later dispersion of the final cometary nuclei into the long-term storage reservoirs. The inclusion of material from the natal interstellar cloud is probable

  5. Two-station television observations of Perseid meteors

    International Nuclear Information System (INIS)

    Hapgood, M.; Rothwell, P.; Royrvik, O.

    1982-01-01

    The predictions of the dustball meteor ablation theory of Hawkes and Jones (Mon. Not. R. Astr. Soc. 1975, 173, 339) have been tested using data from two-station television observations of meteors made during the 1977 and 1978 displays of the Perseid meteor shower. The meteor velocities and the heights at which each meteor began and ended, together with the heights of maximum brightness, were determined for 39 Perseid meteors in the magnitude range Msub(v) = +4 to -2. The beginning heights (hsub(B)) were found to be independent of meteor magnitude; they ranged from 105 to 115 km, with a mean value of hsub(B) = 110 +- 1 km. The end heights (hsub(E)) and the heights of maximum brightness (hsub(M)) were independent of meteor magnitude only up to a critical magnitude Msub(v) = 0 (corresponding to a meteoroid of critical mass of the order of 2 x 10 - 4 kg). Their mean values were hsub(E) = 99 +- 1 km and hsub(M) = 103 +- 1 km respectively. For meteors brighter than Msub(v) = 0, hsub(E) and hsub(M) were, on average, significantly lower than these mean levels, in good qualitative agreement with dustball theory. By assuming that, at the critical mass, dustball meteoroids disintegrate into their constituent grains just before ablation starts, it is found that 3 - 9 x 10 5 J kg - 1 is required to disintegrate Perseid dustball material. This value is several times lower than the value adopted by Hawkes and Jones (1 - 6 x 10 6 J kg - 1 ), suggesting that Perseid material is weaker than the material considered in the theory of dustball ablation. (author)

  6. Modeling Formaldehyde Emission in Comets

    Science.gov (United States)

    Disanti, M. A.; Reuter, D. C.; Bonev, B. P.; Mumma, M. J.; Villanueva, G. L.

    Modeling fluorescent emission from monomeric formaldehyde (H2CO) forms an integral part of our overall comprehensive program of measuring the volatile composition of comets through high-resolution (RP ~ 25,000) infrared spectroscopy using CSHELL at the IRTF and NIRSPEC at Keck II. The H2CO spectra contain lines from both the nu1 (symmetric CH2 stretch) and nu5 (asymmetric CH2 stretch) bands near 3.6 microns. We have acquired high-quality spectra of twelve Oort cloud comets, and at least six of these show clear emission from H2CO. We also detected H2CO with NIRSPEC in one Jupiter Family comet, 9P/Tempel 1, during Deep Impact observations. Our H2CO model, originally developed to interpret low-resolution spectra of comets Halley and Wilson (Reuter et al. 1989 Ap J 341:1045), predicts individual line intensities (g-factors) as a function of rotational temperature for approximately 1300 lines having energies up to approximately 400 cm^-1 above the ground state. Recently, it was validated through comparison with CSHELL spectra of C/2002 T7 (LINEAR), where newly developed analyses were applied to obtain robust determinations of both the rotational temperature and abundance of H2CO (DiSanti et al. 2006 Ap J 650:470). We are currently in the process of extending the model to higher rotational energy (i.e., higher rotational quantum number) in an attempt to improve the fit to high-J lines in our spectra of C/T7 and other comets. Results will be presented, and implications discussed.Modeling fluorescent emission from monomeric formaldehyde (H2CO) forms an integral part of our overall comprehensive program of measuring the volatile composition of comets through high-resolution (RP ~ 25,000) infrared spectroscopy using CSHELL at the IRTF and NIRSPEC at Keck II. The H2CO spectra contain lines from both the nu1 (symmetric CH2 stretch) and nu5 (asymmetric CH2 stretch) bands near 3.6 microns. We have acquired high-quality spectra of twelve Oort cloud comets, and at least six of

  7. Volcanism on differentiated asteroids (Invited)

    Science.gov (United States)

    Wilson, L.

    2013-12-01

    The Dawn spacecraft's investigation of 4 Vesta, best-preserved of the early-forming differentiated asteroids, prompts a reappraisal of factors controlling igneous activity on such bodies. Analogy with melt transfer in zones of partial melting on Earth implies that silicate melts moved efficiently within asteroid mantles in complex networks of veins and dikes, so that only a few percent of the mantle consisted of melt at any one time. Thus even in cases where large amounts of mantle melting occurred, the melts did not remain in the mantle to form "magma oceans", but instead migrated to shallow depths. The link between magma flow rate and the stresses needed to keep fractures open and allow flow fast enough to avoid excessive cooling implies that only within asteroids with radii more than ~190-250 km would continuous magma flow from mantle to surface be possible. In all smaller asteroids (including Vesta) magma must have accumulated in sills at the base of the lithosphere (the conductively controlled ~10 km thick thermal boundary layer) or in crustal magma reservoirs near its base. Magma would then have erupted intermittently to the surface from these steadily replenished reservoirs. The average rates of eruption to the surface (or shallow intrusion) should balance the magma production rate, but since magma could accumulate and erupt intermittently from these reservoirs, the instantaneous eruption rates could be hundreds to thousands of cubic m/s, comparable to historic basaltic eruption rates on Earth and very much greater than the average mantle melting rate. The absence of asteroid atmospheres makes explosive eruptions likely even if magmas are volatile-poor. On asteroids with radii less than ~100 km, gases and sub-mm pyroclastic melt droplets would have had speeds exceeding the escape speed assuming a few hundred ppm volatiles, and only cm sized or larger clasts would have been retained. On larger bodies almost all pyroclasts will have returned to the surface

  8. Comets as Parent Bodies of CI1 Carbonaceous Meteorites and Possible Habitats of Ice-Microbiota

    Science.gov (United States)

    Wickramasinghe, N. Chandra; Wallis, Daryl H.; Rozanov, Alexei Yu.; Hoover, Richard B.

    2011-01-01

    Recent studies of comets and cometary dust have confirmed the presence of biologically relevant organic molecules along with clay minerals and water ice. It is also now well established by deuterium/hydrogen ratios that the CI1 carbonaceous meteorites contain indigenous extraterrestrial water. The evidence of extensive aqueous alteration of the minerals in these meteorites led to the hypothesis that water-bearing asteroids or comets represent the parent bodies of the CI1 (and perhaps CM2) carbonaceous meteorites. These meteorites have also been shown to possess a diverse array of complex organics and chiral and morphological biomarkers. Stable isotope studies by numerous independent investigators have conclusively established that the complex organics found in these meteorites are both indigenous and extraterrestrial in nature. Although the origin of these organics is still unknown, some researchers have suggested that they originated by unknown abiotic mechanisms and may have played a role in the delivery of chiral biomolecules and the origin of life on Early Earth. In this paper we review these results and investigate the thermal history of comets. We show that permanent as well as transient domains of liquid water can be maintained on a comet under a plausible set of assumptions. With each perihelion passage of a comet volatiles are preferentially released, and during millions of such passages the comet could shed crustal debris that may survive transit through the Earth s atmosphere as a carbonaceous meteorite. We review the current state of knowledge of comets and carbonaceous meteorites. We also present the results of recent studies on the long-term viability of terrestrial ice-microbiota encased in ancient glacial ice and permafrost. We suggest that the conditions which have been observed to prevail on many comets do not preclude either survivability (or even the active metabolism and growth) of many types of eukaryotic and prokaryotic microbial

  9. E-type asteroid (2867) Steins as imaged by OSIRIS on board Rosetta.

    Science.gov (United States)

    Keller, H U; Barbieri, C; Koschny, D; Lamy, P; Rickman, H; Rodrigo, R; Sierks, H; A'Hearn, M F; Angrilli, F; Barucci, M A; Bertaux, J-L; Cremonese, G; Da Deppo, V; Davidsson, B; De Cecco, M; Debei, S; Fornasier, S; Fulle, M; Groussin, O; Gutierrez, P J; Hviid, S F; Ip, W-H; Jorda, L; Knollenberg, J; Kramm, J R; Kührt, E; Küppers, M; Lara, L-M; Lazzarin, M; Lopez Moreno, J; Marzari, F; Michalik, H; Naletto, G; Sabau, L; Thomas, N; Wenzel, K-P; Bertini, I; Besse, S; Ferri, F; Kaasalainen, M; Lowry, S; Marchi, S; Mottola, S; Sabolo, W; Schröder, S E; Spjuth, S; Vernazza, P

    2010-01-08

    The European Space Agency's Rosetta mission encountered the main-belt asteroid (2867) Steins while on its way to rendezvous with comet 67P/Churyumov-Gerasimenko. Images taken with the OSIRIS (optical, spectroscopic, and infrared remote( )imaging system) cameras on board Rosetta show that Steins is an oblate body with an effective spherical diameter of 5.3 kilometers. Its surface does not show color variations. The morphology of Steins is dominated by linear faults and a large 2.1-kilometer-diameter crater near its south pole. Crater counts reveal a distinct lack of small craters. Steins is not solid rock but a rubble pile and has a conical appearance that is probably the result of reshaping due to Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) spin-up. The OSIRIS images constitute direct evidence for the YORP effect on a main-belt asteroid.

  10. New approaches to some methodological problems of meteor science

    International Nuclear Information System (INIS)

    Meisel, D.D.

    1987-01-01

    Several low cost approaches to continuous radioscatter monitoring of the incoming meteor flux are described. Preliminary experiments were attempted using standard time frequency stations WWVH and CHU (on frequencies near 15 MHz) during nighttime hours. Around-the-clock monitoring using the international standard aeronautical beacon frequency of 75 MHz was also attempted. The techniques are simple and can be managed routinely by amateur astronomers with relatively little technical expertise. Time series analysis can now be performed using relatively inexpensive microcomputers. Several algorithmic approaches to the analysis of meteor rates are discussed. Methods of obtaining optimal filter predictions of future meteor flux are also discussed

  11. Diuble Station Observation of Telescopic Meteors in Mykolaiv

    Directory of Open Access Journals (Sweden)

    Kulichenko, M.O.

    2017-01-01

    Full Text Available Meteor research using TV CCD unintensified techniques was started in 2011 in Nikolaev astronomical observatory (RI «NAO». The method of meteor registration is based on the combined observation method developed at RI «NAO». The main accent of the research is made on the precise astrometry and meteoroid orbits calculation. In 2013 first double station meteors with low baseline were observed. Estimation of uncertainties of visible radiant equatorial coordinates, geocentric velocity and heliocentric meteoroid orbit parameters was carried out.

  12. Double station observation of faint meteors in Nikolaev

    Science.gov (United States)

    Kulichenko, Mykola; Shulga, Alexandr; Sybiryakova, Yevgeniya

    2016-07-01

    Meteor research using TV CCD unintensified techniques was started in 2011 in Nikolaev astronomical observatory (RI NAO). The method of meteor registration is based on combined observation method developed at RI NAO. The main accent of the research is made on precise astrometry and meteoroid orbits calculation. In 2013 first double station meteors with low baseline were observed. The accuracy of visible radiant estimation is 0.7" with baseline 5 km, and less 0.5" with baseline 11.8 km. The accuracy of velocity and height estimation is 0.5 km/s and 1-2 km.

  13. Spectral Classification of Asteroids by Random Forest

    Science.gov (United States)

    Huang, Chao; Ma, Yue-hua; Zhao, Hai-bin; Lu, Xiao-ping

    2017-10-01

    With the increasing spectral and photometric data of asteroids, a variety of classification methods for asteroids have been proposed. This paper classifies asteroids based on the observations in the Sloan Digital Sky Survey (SDSS) Moving Object Catalogue (MOC) by using the random forest algorithm. In combination with the present taxonomies of Tholen, Bus, Lazzaro, and DeMeo, and the principal component analysis, we have classified 48642 asteroids according to their SDSS magnitudes at the g, r, i, and z wavebands. In this way, these asteroids are divided into 8 (C, X, S, B, D, K, L, and V) classes.

  14. Spectral Classification of Asteroids by Random Forest

    Science.gov (United States)

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

    2016-09-01

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

  15. The dynamical evolution and the force model for asteroid (196256) 2003 EH1

    Science.gov (United States)

    Galushina, T. Yu.; Sambarov, G. E.

    2017-08-01

    This paper is devoted to the dynamics of asteroid (196256) 2003 EH1 which belongs to the Amor group. It is known that asteroid 2003 EH1 is associated with one of the main annual meteor showers - the Quadrantids. In this work we analyze the influence of various perturbing factors on the asteroid motion. The perturbations' estimation was done by five different methods based on the nominal orbit evolution and the size of the initial confidence region. The most significant influences on the dynamical evolution of 2003 EH1 are gravitational forces from the Sun, major planets and the Moon, and the relativistic effects (RE) of the Sun. The Earth, the Sun and Jupiter oblateness; gravitational perturbations from Pallas, Ceres, Vesta and Pluto; and the RE of planets, the Moon, and Pluto are of less importance. The researches of chaoticity and evolution of asteroid 2003 EH1 were examined by integrating its motion equations along with 500 clones. The time interval (1000-4000 years) has been determined by integration precision estimation. We estimated the mean exponential growth factor of nearby orbits (MEGNO) and found that MEGNO < 2 only in the interval from 1700 year to 2300 year. After 2300 year the MEGNO parameter increases that indicates motion instability. It shows that the orbit may be considered as regular on the time interval of ±300 years from now, and as chaotic outside this interval. We suppose that the reasons are the frequent close approaches of the asteroid with Jupiter and the overlap of apsidal-nodal resonances.

  16. METEOR v1.0 - A usage example; METEOR v1.0 - Un ejemplo de uso

    Energy Technology Data Exchange (ETDEWEB)

    Palomo, E.

    1994-07-01

    This script describes a detailed example of the use of the software package METEOR for statistical analysis of meteorological data series. A real spanish meteorological data set is chosen to show the capabilities of METEOR. Output files and resultant plots provided of their interpretations are compiled in three appendixes. The original version of METEOR have been developed by Ph. D.Elena Palomo, CIEMAT-IER, GIASE. It is built by linking programs and routines written in FORTRAN 77 and it adds the graphical capabilities of GNUPLOT. The shape of this toolbox was designed following the criteria of modularity, flexibility and agility criteria. All the input, output and analysis options are structured in three main menus: i) the first is aimed to evaluate the quality of the data set; ii) the second is aimed for pre-processing of the data; and iii) the third is aimed towards the statistical analyses and for creating the graphical outputs. Actually the information about METEOR is constituted by three documents written is spanish: 1) METEOR v1.0: User's guide; 2) METEOR v1.0: A usage example; 3) METEOR v1 .0: Design and structure of the software package. (Author)

  17. Simultaneous Mass Determination for Gravitationally Coupled Asteroids

    Energy Technology Data Exchange (ETDEWEB)

    Baer, James [Private address, 3210 Apache Road, Pittsburgh, PA 15241 (United States); Chesley, Steven R., E-mail: jimbaer1@earthlink.net [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States)

    2017-08-01

    The conventional least-squares asteroid mass determination algorithm allows us to solve for the mass of a large subject asteroid that is perturbing the trajectory of a smaller test asteroid. However, this algorithm is necessarily a first approximation, ignoring the possibility that the subject asteroid may itself be perturbed by the test asteroid, or that the encounter’s precise geometry may be entangled with encounters involving other asteroids. After reviewing the conventional algorithm, we use it to calculate the masses of 30 main-belt asteroids. Compared to our previous results, we find new mass estimates for eight asteroids (11 Parthenope, 27 Euterpe, 51 Neimausa, 76 Freia, 121 Hermione, 324 Bamberga, 476 Hedwig, and 532 Herculina) and significantly more precise estimates for six others (2 Pallas, 3 Juno, 4 Vesta, 9 Metis, 16 Psyche, and 88 Thisbe). However, we also find that the conventional algorithm yields questionable results in several gravitationally coupled cases. To address such cases, we describe a new algorithm that allows the epoch state vectors of the subject asteroids to be included as solve-for parameters, allowing for the simultaneous solution of the masses and epoch state vectors of multiple subject and test asteroids. We then apply this algorithm to the same 30 main-belt asteroids and conclude that mass determinations resulting from current and future high-precision astrometric sources (such as Gaia ) should conduct a thorough search for possible gravitational couplings and account for their effects.

  18. Significance analysis of asteroid pairs

    Czech Academy of Sciences Publication Activity Database

    Pravec, Petr; Vokrouhlický, D.

    2009-01-01

    Roč. 204, č. 2 (2009), s. 580-588 ISSN 0019-1035 R&D Projects: GA ČR GA205/09/1107 Institutional research plan: CEZ:AV0Z10030501 Keywords : asteroid s * dynamics * pairs Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 3.340, year: 2009

  19. 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.

  20. Observations of overdense Quadrantid radio meteors and the variation of the position of stream maxima with meteor magnitude

    International Nuclear Information System (INIS)

    Hughes, D.W.; Taylor, I.W.

    1977-01-01

    Quadrantid across-stream activity profiles are presented for meteors of magnitudes (M) 4.3, 3.8, 3.3, 2.9 and 2.3, based on observations of overdense meteor trails. Not only does the profile become less symmetrical for brighter meteors but also the solar longitude of the stream maximum varies. Radar observations at Sheffield indicate that this variation is of the form: solar longitude = (283.24 +- 0.04) - (0.109 +- 0.010)M through the range 2.3 < M < 7.2. (author)

  1. A brief visit from a red and extremely elongated interstellar asteroid

    Science.gov (United States)

    Meech, Karen J.; Weryk, Robert; Micheli, Marco; Kleyna, Jan T.; Hainaut, Olivier R.; Jedicke, Robert; Wainscoat, Richard J.; Chambers, Kenneth C.; Keane, Jacqueline V.; Petric, Andreea; Denneau, Larry; Magnier, Eugene; Berger, Travis; Huber, Mark E.; Flewelling, Heather; Waters, Chris; Schunova-Lilly, Eva; Chastel, Serge

    2017-12-01

    None of the approximately 750,000 known asteroids and comets in the Solar System is thought to have originated outside it, despite models of the formation of planetary systems suggesting that orbital migration of giant planets ejects a large fraction of the original planetesimals into interstellar space. The high predicted number density of icy interstellar objects (2.4 × 10‑4 per cubic astronomical unit) suggests that some should have been detected, yet hitherto none has been seen. Many decades of asteroid and comet characterization have yielded formation models that explain the mass distribution, chemical abundances and planetary configuration of the Solar System today, but there has been no way of telling whether the Solar System is typical of planetary systems. Here we report observations and analysis of the object 1I/2017 U1 (‘Oumuamua) that demonstrate its extrasolar trajectory, and that thus enable comparisons to be made between material from another planetary system and from our own. Our observations during the brief visit by the object to the inner Solar System reveal it to be asteroidal, with no hint of cometary activity despite an approach within 0.25 astronomical units of the Sun. Spectroscopic measurements show that the surface of the object is spectrally red, consistent with comets or organic-rich asteroids that reside within the Solar System. Light-curve observations indicate that the object has an extremely oblong shape, with a length about ten times its width, and a mean radius of about 102 metres assuming an albedo of 0.04. No known objects in the Solar System have such extreme dimensions. The presence of ‘Oumuamua in the Solar System suggests that previous estimates of the number density of interstellar objects, based on the assumption that all such objects were cometary, were pessimistically low. Planned upgrades to contemporary asteroid survey instruments and improved data processing techniques are likely to result in the detection

  2. Planetary Defense From Space: Part 2 (Simple) Asteroid Deflection Law

    Science.gov (United States)

    Maccone, Claudio

    2006-06-01

    A system of two space bases housing missiles for an efficient Planetary Defense of the Earth from asteroids and comets was firstly proposed by this author in 2002. It was then shown that the five Lagrangian points of the Earth Moon system lead naturally to only two unmistakable locations of these two space bases within the sphere of influence of the Earth. These locations are the two Lagrangian points L1 (in between the Earth and the Moon) and L3 (in the direction opposite to the Moon from the Earth). In fact, placing missiles based at L1 and L3 would enable the missiles to deflect the trajectory of incoming asteroids by hitting them orthogonally to their impact trajectory toward the Earth, thus maximizing the deflection at best. It was also shown that confocal conics are the only class of missile trajectories fulfilling this “best orthogonal deflection” requirement. The mathematical theory developed by the author in the years 2002 2004 was just the beginning of a more expanded research program about the Planetary Defense. In fact, while those papers developed the formal Keplerian theory of the Optimal Planetary Defense achievable from the Earth Moon Lagrangian points L1 and L3, this paper is devoted to the proof of a simple “(small) asteroid deflection law” relating directly the following variables to each other:the speed of the arriving asteroid with respect to the Earth (known from the astrometric observations);the asteroid's size and density (also supposed to be known from astronomical observations of various types);the “security radius” of the Earth, that is, the minimal sphere around the Earth outside which we must force the asteroid to fly if we want to be safe on Earth. Typically, we assume the security radius to equal about 10,000 km from the Earth center, but this number might be changed by more refined analyses, especially in the case of “rubble pile” asteroids;the distance from the Earth of the two Lagrangian points L1 and L3 where the

  3. 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

  4. A confidence index for forecasting of meteor showers

    Science.gov (United States)

    Vaubaillon, Jeremie

    2017-09-01

    The forecasting of meteor showers is currently very good at predicting the timing of meteor outbursts, but still needs further work regarding the level of a given shower. Moreover, uncertainties are rarely provided, leaving the end user (scientist, space agency or the public) with no way to evaluate how much the prediction is trustworthy. A confidence index for the forecasting of meteor showers is presented. It allows one to better understand how a specific forecasting has been performed. In particular, it underlines the role of our current knowledge of the parent body, its past orbit and past activity. The role of close encounters with planets for the time period considered is quantified as well. This confidence index is a first step towards better constrained forecasting of future meteor showers.

  5. TOMS/Meteor-3 Ground Station Overpass Data V008

    Data.gov (United States)

    National Aeronautics and Space Administration — This data product contains TOMS/Meteor-3 Ground Station Overpass Data Version 8 in ASCII format. The overpass data files contain the data derived from the...

  6. Density variations of meteor flux along the Earth's orbit

    International Nuclear Information System (INIS)

    Svetashkova, N.T.

    1987-01-01

    No model of distribution of meteor substance is known to explain the observed diurnal and annual variations of meteor rates, if that distribution is assumed to be constant during the year. Differences between the results of observations and the prediction of diurnal variation rates leads to the conclusion that the density of the orbits of meteor bodies changes with the motion of the Earth along its orbit. The distributions of the flux density over the celestial sphere are obtained by the method described previously by Svetashkova, 1984. The results indicate that the known seasonal and latitudinal variations of atmospheric conditions does not appear to significantly affect the value of the mean flux density of meteor bodies and the matter influx onto the Earth

  7. Intercomparison of radar meteor velocity corrections using different ionization coefficients

    Science.gov (United States)

    Williams, E. R.; Wu, Y.-J.; Chau, J.; Hsu, R.-R.

    2017-06-01

    Sensitive long-wavelength radar observations of absolute velocity never previously published from Jicamarca are brought to bear on the long-standing problem of radar detection of slow-moving meteors. Attention is devoted to evaluating the ionization coefficient β(V) in the critically important velocity range of 11-20 km/s in recent laboratory measurements of Thomas et al. (2016). Theoretical predictions for β(V) based on the laboratory data, on Jones (1997), on Janches et al. (2014), and on Verniani and Hawkins (1964) are used to correct the incoming meteor velocities measured with the sensitive Jicamarca high-power, large-aperture radar operating at 6 m wavelength. All corrected distributions are consistent with the predictions of the Nesvorný model in showing pronounced monotonic increases down to the escape velocity (11 km/s). Such distributions may be essential to explaining the pronounced ledge in nighttime electron density and the rapid disappearance of electrons in meteor trails in the altitude range of 80-85 km.Plain Language SummaryIncoming meteors from space cannot be detected with radars unless the medium around the meteor is strongly ionized. In this study, the distribution of meteor velocities that are detected by the sensitive Jicamarca radar is corrected following theoretical models for the ionization coefficient, a measure of what fraction of the ablated meteor atoms are ionized. The results show that when the distribution of velocities is corrected, one is left with a large population of meteors that are entering the Earth's atmosphere close to the escape speed for the solar system which is 11 km/s.

  8. Automatic Video System for Continues Monitoring of the Meteor Activity

    Czech Academy of Sciences Publication Activity Database

    Koten, Pavel; Fliegel, K.; Vítek, S.; Páta, P.

    2011-01-01

    Roč. 108, č. 1 (2011), s. 69-76 ISSN 0167-9295 R&D Projects: GA ČR GA205/09/1302 Grant - others:GA ČR(CZ) GAP102/10/1320 Institutional research plan: CEZ:AV0Z10030501 Keywords : meteor * meteor showers * instrumentation Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 0.667, year: 2011

  9. Meteor Beliefs Project: Spears of GodSpears of God

    Science.gov (United States)

    Hendrix, Howard V.; McBeath, Alastair; Gheorghe, Andrei Dorian

    2012-04-01

    A selection of genuine or supposedly sky-fallen objects from real-world sources, a mixture of weapons, tools and "magical" objects of heavenly provenance, are drawn from their re-use in the near-future science-fiction novel Spears of God by author Howard V Hendrix, with additional discussion. The book includes other meteoric and meteoritic items too, some of which have been the subject of previous Meteor Beliefs Project examinations.

  10. Measurements of the ionization heights of sporadic radio-meteors

    International Nuclear Information System (INIS)

    Baggaley, W.J.; Webb, T.H.

    1980-01-01

    The echo heights and echo point ionization densities of 4587 sporadic radio-meteors have been determined using a calibrated interferometric height-finding system. Over the height interval 92 to 96 km no association was found between height and ionization but, for radio-meteors ablating above and below this region, significant and opposite trends exist in the data. It is suggested that this could be evidence for the influx of two distinct meteoroid populations. (author)

  11. Meteoroid streams identification amongst 231 Southern hemisphere video meteors

    Czech Academy of Sciences Publication Activity Database

    Jopek, J.; Koten, Pavel; Pecina, Petr

    2010-01-01

    Roč. 404, č. 2 (2010), s. 867-875 ISSN 0035-8711 R&D Projects: GA ČR GA205/00/1728; GA ČR GA205/09/1302 Institutional research plan: CEZ:AV0Z10030501 Keywords : meteor s * meteor oids * data analysis Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 4.888, year: 2010

  12. Green corona, geomagnetic activity and radar meteor rates

    International Nuclear Information System (INIS)

    Prikryl, P.

    1979-01-01

    The short-term dependence of radar meteor rates on geomagnetic activity and/or central meridian passage (CMP) of bright or faint green corona regions is studied. A superimposed-epoch analysis was applied to radar meteor observations from the Ottawa patrol radar (Springhill, Ont.) and Ksub(p)-indices of geomagnetic activity for the period 1963 to 1967. During the minimum of solar activity (1963 to 1965) the CMP of bright coronal regions was followed by the maximum in the daily rates of persistent meteor echoes (>=4s), and the minimum in the daily sums of Ksub(p)-indices whereas the minimum or the maximum, respectively, occurs after the CMP of faint coronal regions. The time delay between the CMP of coronal structures and the corresponding maxima or minima is found to be 3 to 4 days. However, for the period immediately after the minimum of solar activity (1966 to 1967) the above correlation with the green corona is void both for the geomagnetic activity and radar meteor rates. An inverse correlation was found between the radar meteor rates and the geomagnetic activity irrespective of the solar activity. The observed effect can be ascribed to the solar-wind-induced ''geomagnetic'' heating of the upper atmosphere and to the subsequent change in the density gradient in the meteor zone. (author)

  13. Comet Halley: nucleus and jets

    International Nuclear Information System (INIS)

    Sagdeev, R.Z.; Avanesov, G.A.; Barinov, I.V.

    1986-06-01

    The VEGA-1 and VEGA-2 spacecrafts made their closest approach to Comet Halley on 6 and 9 March, respectively. In this paper results of the onboard imaging experiment are discussed. The nucleus of the comet was clearly identifyable as an irregularly shaped object with overall dimensions of (16+-1)x(8+-1)x(8+-1) km. The nucleus rotates around its axis which is nearly perpendicular to the orbital plane, with a period of 53+-2 hours. Its albedo is only 0.04+-002. Most of the jet features observed during the second fly-by were spatially reconstructed. These sources form a quasi-linear structure on the surface. The dust above the surface is shown to be optically thin except certain specific dust jets. Brightness features on the surface are clearly seen. Correlating the data with other measurements it is concluded that the dirty snow-ball model probably has to be revised. (author)

  14. Rationalization of Comet Halley's periods

    Science.gov (United States)

    Belton, Michael J. S.

    1990-01-01

    The sense of long axis orientation of Comet Halley during the Vega 1 encounter must be reversed from that deduced by Sagdeev et al. (1986) in order to harmonize the comet nucleus' Vega/Giotto-observed orientations with periodicities extracted from time-series brightness data. It is also demonstrated that Vega/Giotto observations can be satisfied by either a 2.2- or 3.7-day long-axis free precession period. A novel Fourier algorithm is used to reanalyze five independent data sets; strong evidence is adduced for periods harmonically related to a 7.4-day period. The preferred candidate models for Halley's nuclear rotation are characterized by a long-axis precession period of 3.7 days.

  15. Spectroscopic Evidence for the Asteroidal Nature of the July 2009 Jovian Impactor

    Science.gov (United States)

    Lisse, Carey; Orton, Glenn; Yanamandra-Fisher, Padma; Fletcher, Leigh; Depater, Imke; Hammel, Heidi

    2010-05-01

    The collision of a large object with Jupiter on July 19, 2009, heated its atmosphere, modified its composition and generated a prominent field of deposited particulate debris. Low-resolution 7-24 μm spectroscopy of the impact field obtained using the T-ReCS mid-infrared camera/spectrometer on Gemini/South on 24 July 2009 has revealed an excess 9-μm absorption in the impact debris in addition to that supplied by hot ammonia created in the impact. We have searched for candidate materials that would best fit the spectral feature near 9 μm, and find that the feature cannot be matched with candidate materials in Jupiter's atmosphere. A search through a large suite of gaseous and solid absorption spectra (c.f Lisse et al. 2008, 2009) revealed that the major competent matches were for (a) obsidian, a glassy silica, and (b) quartz and cristobalite, crystalline silicas, kinetic alteration products of primitive body ferromagnesian silicates formed at high pressures and temperatures over 1500 K. There are also weak features at 10 - 11 um consistent with olivine absorptions. While the high temperatures required to create silicas are also high enough to destroy the non-refractory water and organics dominating icy cometary bodies, and thus destroy their spectral signal, there was no detectable absorption due to pyroxene materials, which, along with olivines in roughly equal measure, comprise the majority of refractory silicaceous species found in comets (Lisse et al. 2007). This suggests that the impacting body was not a comet, but an olivine-rich differentiated body similar to asteroids that are abundant in the outer regions of the main asteroid belt (Lodders and Fegley 1998). We speculate that the weak structural strength of bulk cometary material causes a comet impactor to catastrophically disrupt at higher altitudes and lower temperatures than a strong, dense asteroidal body, so that the cometary refractory dust component remains relatively cold and unaltered through

  16. Solar wind stagnation near comets

    International Nuclear Information System (INIS)

    Galeev, A.A.; Cravens, T.E.; Gombosi, T.I.

    1983-03-01

    The nature of the solar wind flow near comets is examined analytically. In particular, the typical values for the stagnation pressure and magnetic barrier strength are estimated, taking into account the magnetic field line tension and the charge exchange cooling of the mass loaded solar wind. Knowledge of the strength of the magnetic barrier is required in order to determine the location of the contact discontinuity which separates the contaminated solar wind plasma and the outflowing plasma of the cometary ionosphere. (author)

  17. Asteroid exploration and utilization: The Hawking explorer

    Science.gov (United States)

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

    1991-01-01

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

  18. 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.

  19. The Asteroid 2000 ET70

    Science.gov (United States)

    Vodniza, Alberto Q.; Pereira, M. R.

    2012-10-01

    The asteroid 2000 ET70 (162421) was discovered by Lincoln Laboratory ETS (LINEAR) in New Mexico on March 8, 2000. Whiteley (2001) classified 2000 ET70 as an X-type object: This asteroid belongs to an ambiguous group that includes objects that are large and dark, metallic.The composition of this asteroid is unknown.The asteroid was at 0.0454430 U.A from the Earth on February 19.85956 (2012) and it will be at approximately 0.1503270 A.U from the Earth on August 21.07061 (2012).The asteroid 2000 ET70 was studied by radar in Arecibo and Goldstone. Shantanu Naidu and Jean-Luc Margot studied this object by Arecibo radar (Feb 13-2012) and they suggest that 2000 ET70 is roughly 1.5 km in diameter and that it has a period of rotation of about 9.5 hours. It has an orbital period of 0.92 years.From our Observatory, located in Pasto-Colombia, we captured several pictures, videos and astrometry data during three days. Our data was published by the Minor Planet Center (MPC) and also appears at the web page of NEODyS. Our observatory’s code at the MPC is “H78”. Pictures of the asteroid were captured with the following equipment: 14” LX200 GPS MEADE (f/10 Schmidt-Cassegrain Telescope) and STL-1001 SBIG camera.Astrometry was carried out, and we calculated the orbital elements. We obtained the following orbital parameters: eccentricity = 0.1243231, semi-major axis = 0.94541495 A.U, orbital inclination = 22.32919 deg, longitude of the ascending node = 331.05007 deg, argument of perihelion = 45.20913 deg, orbital period = 0.92 years (335.76 days), mean motion = 1.07218658 deg/d, perihelion distance = 0.82787796 A.U, aphelion distance = 1.06295195 A.U. The parameters were calculated based on 71 observations (2012 Mar. 1-7) with mean residual = 0.262 arcseconds.

  20. Comet coma sample return instrument

    Science.gov (United States)

    Albee, A. L.; Brownlee, Don E.; Burnett, Donald S.; Tsou, Peter; Uesugi, K. T.

    1994-01-01

    The sample collection technology and instrument concept for the Sample of Comet Coma Earth Return Mission (SOCCER) are described. The scientific goals of this Flyby Sample Return are to return to coma dust and volatile samples from a known comet source, which will permit accurate elemental and isotopic measurements for thousands of individual solid particles and volatiles, detailed analysis of the dust structure, morphology, and mineralogy of the intact samples, and identification of the biogenic elements or compounds in the solid and volatile samples. Having these intact samples, morphologic, petrographic, and phase structural features can be determined. Information on dust particle size, shape, and density can be ascertained by analyzing penetration holes and tracks in the capture medium. Time and spatial data of dust capture will provide understanding of the flux dynamics of the coma and the jets. Additional information will include the identification of cosmic ray tracks in the cometary grains, which can provide a particle's process history and perhaps even the age of the comet. The measurements will be made with the same equipment used for studying micrometeorites for decades past; hence, the results can be directly compared without extrapolation or modification. The data will provide a powerful and direct technique for comparing the cometary samples with all known types of meteorites and interplanetary dust. This sample collection system will provide the first sample return from a specifically identified primitive body and will allow, for the first time, a direct method of matching meteoritic materials captured on Earth with known parent bodies.

  1. Halley comet, implication on the origin

    International Nuclear Information System (INIS)

    Festou, M.C.

    1990-01-01

    One will first give a rapid description of the different parts that compose a comet coma. Then one will describe the spectrum of comets from the UV to the IR regions with special emphasis on how information relative to the physico-chemistry of comet atmospheres can be retrieved. Our basic knowledge about the composition of comets before 1985 will be summarized and the input of the 1985-86 observing campaign of comet Halley will be shown (in situ, ground-based and space borne observations). One will see then that the chemical composition of comets appears as of today completely compatible with a formation from pre-solar matter that condensed inside the solar system [fr

  2. METEOR v1.0 - User's Guide; METEOR v1.0 - Guia de Usuarios

    Energy Technology Data Exchange (ETDEWEB)

    Palomo, E.

    1994-07-01

    This script is a User's Guide for the software package METEOR for statistical analysis of meteorological data series. The original version of METEOR have been developed by Ph.D. Elena Palomo, CIEMAT-IER, GIMASE. It is built by linking programs and routines written in FORTRAN 77 and it adds the graphical capabilities of GNUPLOT. The shape of this toolbox was designed following the criteria of modularity, flexibility and agility criteria. All the input, output and analysis options are structured in three main menus: i) the first is aimed to evaluate the quality of the data set; ii) the second is aimed for pre-processing of the data; and iii) the third is aimed towards the statistical analyses and for creating the graphical outputs. Actually the information about METEOR is constituted by three documents written in spanish: 1) METEOR v1.0: User's guide; 2) METEOR v1.0: A usage example; 3) METEOR v1.0: Design and structure of the software package. (Author)

  3. The asteroid 2014 JO25

    Science.gov (United States)

    Vodniza, Alberto; Pereira, Mario

    2017-10-01

    The asteroid 2014 JO25 was discovered by A. D. Grauer at the Mt. Lemmon Survey on May 2014, and Joe Masiero used observations from the NEOWISE in 2014 to estimate a diameter of 650 meters [1]. However, using the radio telescope at Arecibo-Puerto Rico, astronomers obtained radar images on April 17-2017 and Edgar Rivera Valentín (scientist at Arecibo) said: “We found 2014 JO25 is a contact binary asteroid, two space rocks that were originally separate bodies, and each segment is about 640 meters and 670 meters, for a total of about 1.3 km long. Its rotation is of 3.5 hours” [2]. This asteroid flew past Earth on April 19 at a distance of about 4.6 lunar distances from the Earth. This was the closest approach by an asteroid since 4179 Toutatis. Toutatis flew past Earth on September 2004 at a distance of about 4 lunar distances from the Earth [3]. In April 12-2020 the asteroid will be at a minimum possible distance of 0.1617280 A.U from Earth [4]. From our observatory, located in Pasto-Colombia, we obtained a lot of pictures. Our data was published by the Minor Planet Center [5] and also appears at the web page of NEODyS [6]. Astrometry and photometry were carried out, and we calculated the orbital elements. We obtained the following orbital parameters: eccentricity=0.88454+/-0.00152, semi-major axis= 2.0573+/- 0.0216 A.U, orbital inclination=25.22+/-0.10 deg, longitude of the ascending node =30.6530+/-0.0032 deg, argument of perihelion=49.586+/-0.012 deg, mean motion = 0.33402+/-0.00527 deg/d, perihelion distance=0.237524+/-0.000644 A.U, aphelion distance=3.8770+/-0.0449 A.U, absolute magnitude =18.1. The parameters were calculated based on 164 observations. Dates: 2017 April: 22 to 24 with mean residual=0.22 arcseconds.The asteroid has an orbital period of 2.95 years.[1] https://echo.jpl.nasa.gov/asteroids/2014JO25/2014JO25_planning.html[2] http://earthsky.org/astronomy-essentials/large-asteroid-2014-jo25-close-april-19-2017-how-to-see[3] https

  4. Mining the Apollo and Amor asteroids

    Science.gov (United States)

    Oleary, B.

    1977-01-01

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

  5. 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...

  6. The source of solar energy, ca. 1840-1910: From meteoric hypothesis to radioactive speculations

    Science.gov (United States)

    Kragh, Helge

    2016-12-01

    Why does the Sun shine? Today we know the answer to the question and we also know that earlier answers were quite wrong. The problem of the source of solar energy became an important part of physics and astronomy only with the emergence of the law of energy conservation in the 1840s. The first theory of solar heat based on the new law, due to J.R. Mayer, assumed the heat to be the result of meteors or asteroids falling into the Sun. A different and more successful version of gravitation-to-heat energy conversion was proposed by H. Helmholtz in 1854 and further developed by W. Thomson. For more than forty years the once so celebrated Helmholtz-Thomson contraction theory was accepted as the standard theory of solar heat despite its prediction of an age of the Sun of only 20 million years. In between the gradual demise of this theory and the radically different one based on nuclear processes there was a period in which radioactivity was considered a possible alternative to gravitational contraction. The essay discusses various pre-nuclear ideas of solar energy production, including the broader relevance of the question as it was conceived in the Victorian era.

  7. Investigating the Geological History of Asteroid 101955 Bennu Through Remote Sensing and Returned Sample Analyses

    Science.gov (United States)

    Messenger, S.; Connolly, H. C., Jr.; Lauretta, D. S.; Bottke, W. F.

    2014-01-01

    The NASA New Frontiers Mission OSRIS-REx will return surface regolith samples from near-Earth asteroid 101955 Bennu in September 2023. This target is classified as a B-type asteroid and is spectrally similar to CI and CM chondrite meteorites [1]. The returned samples are thus expected to contain primitive ancient Solar System materials that formed in planetary, nebular, interstellar, and circumstellar environments. Laboratory studies of primitive astromaterials have yielded detailed constraints on the origins, properties, and evolutionary histories of a wide range of Solar System bodies. Yet, the parent bodies of meteorites and cosmic dust are generally unknown, genetic and evolutionary relationships among asteroids and comets are unsettled, and links between laboratory and remote observations remain tenuous. The OSIRIS-REx mission will offer the opportunity to coordinate detailed laboratory analyses of asteroidal materials with known and well characterized geological context from which the samples originated. A primary goal of the OSIRIS-REx mission will be to provide detailed constraints on the origin and geological and dynamical history of Bennu through coordinated analytical studies of the returned samples. These microanalytical studies will be placed in geological context through an extensive orbital remote sensing campaign that will characterize the global geological features and chemical diversity of Bennu. The first views of the asteroid surface and of the returned samples will undoubtedly bring remarkable surprises. However, a wealth of laboratory studies of meteorites and spacecraft encounters with primitive bodies provides a useful framework to formulate priority scientific questions and effective analytical approaches well before the samples are returned. Here we summarize our approach to unraveling the geological history of Bennu through returned sample analyses.

  8. Geotechnical Tests on Asteroid Simulant Orgueil

    Science.gov (United States)

    Garcia, Alexander D'marco

    2017-01-01

    In the last 100 years, the global population has more than quadrupled to over seven billion people. At the same time, the demand for food and standard of living has been increasing which has amplified the global water use by nearly eight times from approximately 500 to 4000 cu km per yr from 1900 to 2010. With the increasing concern to sustain the growing population on Earth it is necessary to seek other approaches to ensure that our planet will have resources for generations to come. In recent years, the advancement of space travel and technology has allowed the idea of mining asteroids with resources closer to becoming a reality. During the duration of the internship at NASA Kennedy Space Center, several geotechnical tests were conducted on BP-1 lunar simulant and asteroid simulant Orgueil. The tests that were conducted on BP-1 was to practice utilizing the equipment that will be used on the asteroid simulant and the data from those tests will be omitted from report. Understanding the soil mechanics of asteroid simulant Orgueil will help provide basis for future technological advances and prepare scientists for the conditions they may encounter when mining asteroids becomes reality in the distant future. Distinct tests were conducted to determine grain size distribution, unconsolidated density, and maximum density. Once the basic properties are known, the asteroid simulant will be altered to different levels of compaction using a vibrator table to see how compaction affects the density. After different intervals of vibration compaction, a miniature vane shear test will be conducted. Laboratory vane shear testing is a reliable tool to investigate strength anisotropy in the vertical and horizontal directions of a very soft to stiff saturated fine-grained clayey soil. This test will provide us with a rapid determination of the shear strength on the undisturbed compacted regolith. The results of these tests will shed light on how much torque is necessary to drill

  9. ASTEROID DYNAMICAL FAMILIES V2.0

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set contains the Zappala et al. (1995) [ZAPPALAETAL1995] asteroid dynamical families classifications, based on the hierarchical clustering method applied...

  10. ASTEROID TAXONOMY V2.0

    Data.gov (United States)

    National Aeronautics and Space Administration — This dataset provides taxonomic classifications of asteroids in each of four different systems: Tholen (1984, 1989) THOLEN1984, THOLEN1989 [TEDESCOETAL1989

  11. ASTEROID DYNAMICAL FAMILIES V3.0

    Data.gov (United States)

    National Aeronautics and Space Administration — This dataset contains the asteroid dynamical family classifications contained in Zappala, et al. (1995) [ZAPPALAETAL1995]. These are based on the heirarchical...

  12. The Compositional Structure of the Asteroid Belt

    Science.gov (United States)

    DeMeo, F. E.; Alexander, C. M. O'D.; Walsh, K. J.; Chapman, C. R.; Binzel, R. P.

    The past decade has brought major improvements in large-scale asteroid discovery and characterization, with over half a million known asteroids, more than 100,000 of which have 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 chapter reviews the advancements on the fronts of asteroid compositional characterization, meteorite measurements, and dynamical theories in the context of the heliocentric distribution of asteroid compositions seen in the main belt today. This chapter also reviews the major outstanding questions relating to asteroid compositions and distributions and summarizes the progress and current state of understanding of these questions to form the big picture of the formation and evolution of asteroids in the main belt. Finally, we briefly review the relevance of asteroids and their compositions in their greater context within our solar system and beyond.

  13. ASTEROID POLARIMETRIC DATABASE V3.0

    Data.gov (United States)

    National Aeronautics and Space Administration — The Asteroid Polarimetric Database (APD) is compiled by Dmitrij Lupishko of Kharkov University. This database tabulates the original data comprising degree of...

  14. ASTEROID POLARIMETRIC DATABASE V4.0

    Data.gov (United States)

    National Aeronautics and Space Administration — The Asteroid Polarimetric Database (APD) is compiled by Dmitrij Lupishko of Kharkov University. This database tabulates the original data comprising degree of...

  15. ASTEROID POLARIMETRIC DATABASE V2.0

    Data.gov (United States)

    National Aeronautics and Space Administration — The Asteroid Polarimetric Database (APD) is compiled by Dmitrij Lupishko of Kharkov University. This database tabulates the original data comprising degree of...

  16. ASTEROID POLARIMETRIC DATABASE V1.0

    Data.gov (United States)

    National Aeronautics and Space Administration — The Asteroid Polarimetric Database (APD) is compiled by Dmitrij Lupishko of Kharkov University. This database tabulates the original data comprising degree of...

  17. Comet Dust After Deep Impact

    Science.gov (United States)

    Wooden, Diane H.; Harker, David E.; Woodward, Charles E.

    2006-01-01

    When the Deep Impact Mission hit Jupiter Family comet 9P/Tempel 1, an ejecta crater was formed and an pocket of volatile gases and ices from 10-30 m below the surface was exposed (A Hearn et aI. 2005). This resulted in a gas geyser that persisted for a few hours (Sugita et al, 2005). The gas geyser pushed dust grains into the coma (Sugita et a1. 2005), as well as ice grains (Schulz et al. 2006). The smaller of the dust grains were submicron in radii (0-25.3 micron), and were primarily composed of highly refractory minerals including amorphous (non-graphitic) carbon, and silicate minerals including amorphous (disordered) olivine (Fe,Mg)2SiO4 and pyroxene (Fe,Mg)SiO3 and crystalline Mg-rich olivine. The smaller grains moved faster, as expected from the size-dependent velocity law produced by gas-drag on grains. The mineralogy evolved with time: progressively larger grains persisted in the near nuclear region, having been imparted with slower velocities, and the mineralogies of these larger grains appeared simpler and without crystals. The smaller 0.2-0.3 micron grains reached the coma in about 1.5 hours (1 arc sec = 740 km), were more diverse in mineralogy than the larger grains and contained crystals, and appeared to travel through the coma together. No smaller grains appeared at larger coma distances later (with slower velocities), implying that if grain fragmentation occurred, it happened within the gas acceleration zone. These results of the high spatial resolution spectroscopy (GEMINI+Michelle: Harker et 4. 2005, 2006; Subaru+COMICS: Sugita et al. 2005) revealed that the grains released from the interior were different from the nominally active areas of this comet by their: (a) crystalline content, (b) smaller size, (c) more diverse mineralogy. The temporal changes in the spectra, recorded by GEMIM+Michelle every 7 minutes, indicated that the dust mineralogy is inhomogeneous and, unexpectedly, the portion of the size distribution dominated by smaller grains has

  18. Spectrophotometry of 25 comets - Post-Halley updates for 17 comets plus new observations for eight additional comets

    Science.gov (United States)

    Newburn, Ray L., Jr.; Spinrad, Hyron

    1989-01-01

    The best possible production figures within the current post-Halley framework and available observations are given for H2O, O(1D), CN, C3, C2 and dust in 25 comets. Of these, the three objects with the smallest mixing ratios of all minor species have moderate to little or no dust and appear 'old'. Comets with large amounts of CN are very dusty, and there is a clear correlation of CN with dust, although comets with little or no dust still have some CN. Thus, CN appears to have at least two sources, dust and one or more parent gases. Also, the C2/CN production ratio changes continuously with heliocentric distance in every comet considered, suggesting that C2 production may be a function of coma density as well as parental abundance. Dust production ranges from essentially zero in Comet Sugano-Saigusa-Fujikawa up to 67,000 kg/s for Halley on March 14, 1986.

  19. Charles Olivier and the rise of meteor science

    CERN Document Server

    Taibi, Richard

    2017-01-01

    This fascinating portrait of an amateur astronomy movement tells the story of how Charles Olivier recruited a hard-working cadre of citizen scientists to rehabilitate the study of meteors. By 1936, Olivier and members of his American Meteor Society had succeeded in disproving an erroneous idea about meteor showers. Using careful observations, they restored the public’s trust in predictions about periodic showers and renewed respect for meteor astronomy among professional astronomers in the United States. Charles Olivier and his society of observers who were passionate about watching for meteors in the night sky left a major impact on the field. In addition to describing Olivier’s career and describing his struggles with competitive colleagues in a hostile scientific climate, the author provides biographies of some of the scores of women and men of all ages who aided Olivier in making shower observations, from the Leonids and Perseids and others. Half of these amateur volunteers were from 13 to 25 years of...

  20. Division F Commission 22: Meteors, Meteorites, and Interplanetary Dust

    Science.gov (United States)

    Jenniskens, Peter; Borovička, Jiří; Watanabe, Jun-Ichi; Jopek, Tadeusz; Abe, Shinsuke; Consolmagno, Guy J.; Ishiguro, Masateru; Janches, Diego; Ryabova, Galina O.; Vaubaillon, Jérémie; Zhu, Jin

    2016-04-01

    Commission 22 (Meteors, Meteorites and Interplanetary Dust) was established at the first IAU General Assembly held in Rome in 1922, with William Frederick Denning as its first President. Denning was an accountant by profession, but as an amateur astronomer he contributed extensively to meteor science. Commission 22 thus established a pattern that has continued to this day that non-professional astronomers were welcomed and valued and could play a significant role in its affairs. The field of meteors, meteorites and interplanetary dust has played a disproportional role in the astronomical perception of the general public through the majestic displays of our annual meteor showers. Those in the field deployed many techniques uncommon in other fields of astronomy, studying the ``vermin of space'', the small solid bodies that pervade interplanetary space and impact Earth's atmosphere, the surface of the Moon, and that of our satellites in orbit. Over time, the field has tackled a wide array of problems, from predicting the encounter with meteoroid streams, to the origin of our meteorites and the nature of the zodiacal cloud. Commission 22 has played an important role in organizing the field through dedicated meetings, a data centre, and working groups that developed professional-amateur relationships and that organized the nomenclature of meteor showers. The contribution of Commission 22 to the field is perhaps most readily seen in the work of the presidents that followed in the footsteps of Denning.

  1. Improving Photometric Calibration of Meteor Video Camera Systems

    Science.gov (United States)

    Ehlert, Steven; Kingery, Aaron; Suggs, Robert

    2017-01-01

    We present the results of new calibration tests performed by the NASA Meteoroid Environment Office (MEO) designed to help quantify and minimize systematic uncertainties in meteor photometry from video camera observations. These systematic uncertainties can be categorized by two main sources: an imperfect understanding of the linearity correction for the MEO's Watec 902H2 Ultimate video cameras and uncertainties in meteor magnitudes arising from transformations between the Watec camera's Sony EX-View HAD bandpass and the bandpasses used to determine reference star magnitudes. To address the first point, we have measured the linearity response of the MEO's standard meteor video cameras using two independent laboratory tests on eight cameras. Our empirically determined linearity correction is critical for performing accurate photometry at low camera intensity levels. With regards to the second point, we have calculated synthetic magnitudes in the EX bandpass for reference stars. These synthetic magnitudes enable direct calculations of the meteor's photometric flux within the camera bandpass without requiring any assumptions of its spectral energy distribution. Systematic uncertainties in the synthetic magnitudes of individual reference stars are estimated at approx. 0.20 mag, and are limited by the available spectral information in the reference catalogs. These two improvements allow for zero-points accurate to 0.05 - 0.10 mag in both filtered and unfiltered camera observations with no evidence for lingering systematics. These improvements are essential to accurately measuring photometric masses of individual meteors and source mass indexes.

  2. Catalogue of Meteor Showers and Storms in Korean History

    Directory of Open Access Journals (Sweden)

    Sang-Hyeon Ahn

    2004-03-01

    Full Text Available We present a more complete and accurate catalogue of astronomical records for meteor showers and meteor storms appeared in primary official Korean history books, such as Samguk-sagi, Koryo-sa, Seungjeongwon-ilgi, and Choson-Wangjo-Sillok. So far the catalogue made by Imoto and Hasegawa in 1958 has been widely used in the international astronomical society. The catalogue is based on a report by Sekiguchi in 1917 that is mainly based on secondary history books. We observed that the catalogue has a number of errors in either dates or sources of the records. We have thoroughly checked the primary official history books, instead of the secondary ones, in order to make a corrected and extended catalogue. The catalogue contains 25 records of meteor storms, four records of intense meteor-showers, and five records of usual showers in Korean history. We also find that some of those records seem to correspond to some presently active meteor showers such as the Leonids, the Perseids, and the ¥ç-Aquarids-Orionids pair. However, a large number of those records do not correspond to such present showers. This catalogue we obtained can be useful for various astrophysical studies in the future.

  3. Devolatilization or melting of carbonates at Meteor Crater, AZ?

    Science.gov (United States)

    Hörz, F.; Archer, P. D.; Niles, P. B.; Zolensky, M. E.; Evans, M.

    2015-06-01

    We have investigated the carbonates in the impact melts and in a monolithic clast of highly shocked Coconino sandstone of Meteor Crater, AZ to evaluate whether melting or devolatilization is the dominant response of carbonates during high-speed meteorite impact. Both melt- and clast-carbonates are calcites that have identical crystal habits and that contain anomalously high SiO2 and Al2O3. Also, both calcite occurrences lack any meteoritic contamination, such as Fe or Ni, which is otherwise abundantly observed in all other impact melts and their crystallization products at Meteor Crater. The carbon and oxygen isotope systematics for both calcite deposits suggest a low temperature environment (impact melts, yield 100 wt% element totals by EMPA, suggesting complete loss of CO2. The target dolomite decomposed into MgO, CaO, and CO2; the CO2 escaped and the CaO and MgO combined with SiO2 from coexisting quartz and FeO from the impactor to produce the dominant impact melt at Meteor Crater. Although confined to Meteor Crater, these findings are in stark contrast to Osinski et al. (2008) who proposed that melting of carbonates, rather than devolatilization, is the dominant process during hypervelocity impact into carbonate-bearing targets, including Meteor Crater.

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

    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...

  5. Meteoric 10Be in soil profiles - A global meta-analysis

    Science.gov (United States)

    Graly, Joseph A.; Bierman, Paul R.; Reusser, Lucas J.; Pavich, Milan J.

    2010-01-01

    In order to assess current understanding of meteoric 10Be dynamics and distribution in terrestrial soils, we assembled a database of all published meteoric 10Be soil depth profiles, including 104 profiles from 27 studies in globally diverse locations, collectively containing 679 individual measurements. This allows for the systematic comparison of meteoric 10Be concentration to other soil characteristics and the comparison of profile depth distributions between geologic settings. Percent clay, 9Be, and dithionite-citrate extracted Al positively correlate to meteoric 10Be in more than half of the soils where they were measured, but the lack of significant correlation in other soils suggests that no one soil factor controls meteoric 10Be distribution with depth. Dithionite-citrate extracted Fe and cation exchange capacity are only weakly correlated to meteoric 10Be. Percent organic carbon and pH are not significantly related to meteoric 10Be concentration when all data are complied.The compilation shows that meteoric 10Be concentration is seldom uniform with depth in a soil profile. In young or rapidly eroding soils, maximum meteoric 10Be concentrations are typically found in the uppermost 20 cm. In older, more slowly eroding soils, the highest meteoric 10Be concentrations are found at depth, usually between 50 and 200 cm. We find that the highest measured meteoric 10Be concentration in a soil profile is an important metric, as both the value and the depth of the maximum meteoric 10Be concentration correlate with the total measured meteoric 10Be inventory of the soil profile.In order to refine the use of meteoric 10Be as an estimator of soil erosion rate, we compare near-surface meteoric 10Be concentrations to total meteoric 10Be soil inventories. These trends are used to calibrate models of meteoric 10Be loss by soil erosion. Erosion rates calculated using this method vary based on the assumed depth and timing of erosional events and on the reference data selected.

  6. Amino Acids from a Comet

    Science.gov (United States)

    Cook, Jamie Elisla

    2009-01-01

    NASA's Stardust spacecraft returned samples from comet 81P/Wild 2 to Earth in January 2006. Examinations of the organic compounds in cometary samples can reveal information about the prebiotic organic inventory present on the early Earth and within the early Solar System, which may have contributed to the origin of life. Preliminary studies of Stardust material revealed the presence of a suite of organic compounds including several amines and amino acids, but the origin of these compounds (cometary- vs. terrestrial contamination) could not be identified. We have recently measured the carbon isotopic ratios of these amino acids to determine their origin, leading to the first detection of a coetary amino acid.

  7. Linear feature detection algorithm for astronomical surveys - II. Defocusing effects on meteor tracks

    Science.gov (United States)

    Bektešević, Dino; Vinković, Dejan; Rasmussen, Andrew; Ivezić, Željko

    2018-03-01

    Given the current limited knowledge of meteor plasma micro-physics and its interaction with the surrounding atmosphere and ionosphere, meteors are a highly interesting observational target for high-resolution wide-field astronomical surveys. Such surveys are capable of resolving the physical size of meteor plasma heads, but they produce large volumes of images that need to be automatically inspected for possible existence of long linear features produced by meteors. Here, we show how big aperture sky survey telescopes detect meteors as defocused tracks with a central brightness depression. We derive an analytic expression for a defocused point source meteor track and use it to calculate brightness profiles of meteors modelled as uniform brightness discs. We apply our modelling to meteor images as seen by the Sloan Digital Sky Survey and Large Synoptic Survey Telescope telescopes. The expression is validated by Monte Carlo ray-tracing simulations of photons travelling through the atmosphere and the Large Synoptic Survey Telescope telescope optics. We show that estimates of the meteor distance and size can be extracted from the measured full width at half-maximum and the strength of the central dip in the observed brightness profile. However, this extraction becomes difficult when the defocused meteor track is distorted by the atmospheric seeing or contaminated by a long-lasting glowing meteor trail. The full width at half-maximum of satellite tracks is distinctly narrower than meteor values, which enables removal of a possible confusion between satellites and meteors.

  8. Ex-dormant comets that come back to life: a search of reactivated comets

    Science.gov (United States)

    Quan-Zhi, YE

    2017-10-01

    Dormant or near-dormant short-period comets can unexpectedly regain the ability to eject dust. In many known cases, the resurrection is short-lived and lasts less than one orbit. However, it is possible that some resurrected comets can remain active in later perihelion passages. Here we conduct a search in the archival images of various facilities to look for these “reactivated” comets. We identify two candidates, 297P/Beshore and 332P/Ikeya-Murakami, both of which were found to be inactive or weakly active in the previous orbit before their discovery. We derive a reactivation rate of 0.007 events per comet per orbit, which implies that typical short-period comets only become temporarily dormant a few times or less. Smaller comets are prone to rotational instability and may undergo temporary dormancy more frequently. Next generation high-cadence surveys may find more reactivation events of these comets.

  9. Comet mission hopes to uncover Earth's origins

    CERN Multimedia

    Henderson, M

    2004-01-01

    "A European spacecraft that will hunt down a comet in search of clues to the origin of life on Earth will blast off tomorrow from the Kourou spaceport in French Guiana. The Rosetta probe will take 12 years to catch up with Churyumov-Gerasimenko before becoming the first spacecraft to make a soft, controlled landing on a comet's nucleus" (1 page).

  10. Comet assay on mice testicular cells

    DEFF Research Database (Denmark)

    Sharma, Anoop Kumar

    2015-01-01

    of the comet assay in testicular cells. The chemicals included environmentally relevant substances such as Bisphenol A, PFOS and Tetrabrombisphenol A. Statistical power calculations will be presented to aid in the design of future Comet assay studies on testicular cells. Power curves were provided...

  11. RFP for the Comet Nuclei Tour (CONTOUR)

    DEFF Research Database (Denmark)

    Jørgensen, John Leif; Madsen, Peter Buch; Betto, Maurizio

    1999-01-01

    This document describes the ASC Star Tracker (performance, functionality, requirements etc.) to The Johns Hopkins University - Applied Physics Laboratory for their Comet Nuclei TOUR (CONTOUR) Program.......This document describes the ASC Star Tracker (performance, functionality, requirements etc.) to The Johns Hopkins University - Applied Physics Laboratory for their Comet Nuclei TOUR (CONTOUR) Program....

  12. The Geology of Comet 19/P Borrelly

    Science.gov (United States)

    Britt, D. T.; Boice, D. C; Buratti, B. J.; Hicks, M. D.; Nelson, R. M.; Oberst, J.; Sandel, B. R.; Soderblom, L. A.; Stern, S. A.; Thomas, N.

    2002-01-01

    The Deep Space One spacecraft flew by Comet 19P/Borrelly on September 22, 2001 and returned a rich array of imagery with resolutions of up to 48 m/pixel. These images provide a window into the surface structure, processes, and geological history of a comet. Additional information is contained in the original extended abstract.

  13. Encounter of a different kind: Rosetta observes asteroid at close quarters

    Science.gov (United States)

    2008-09-01

    ESA's comet chaser, Rosetta, last night flew by a small body in the main asteroid belt, asteroid Steins, collecting a wealth of information about this rare type of minor Solar System body. At 20:58 CEST (18:58 UT) last night, ESA's Rosetta probe approached asteroid 2867 Steins, coming to within a distance of only 800 km from it. Steins is Rosetta's first nominal scientific target in its 11½ year mission to ultimately explore the nucleus of Comet 67P/Churyumov-Gerasimenko. The success of this 'close' encounter was confirmed at 22:14 CEST, when ESA's ground control team at the European Space Operations Centre (ESOC) in Darmstadt, Germany, received initial telemetry from the spacecraft. During the flyby operations, Rosetta was out of reach as regards communication links because its antenna had to be turned away from Earth. At a distance of about 2.41 AU (360 million kilometres) from our planet, the radio signal from the probe took 20 minutes to reach the ground. Steins is a small asteroid of irregular shape with a diameter of only 4.6 km. It belongs to the rare class of E-type asteroids, which had not been directly observed by an interplanetary spacecraft before. Such asteroids are quite small in size and orbit and are mostly found in the inner part of the main asteroid belt located between Mars and Jupiter. They probably originate from the mantle of larger asteroids destroyed in the early history of the Solar System, and are thought to be composed mainly of silicate minerals with little or no iron content. The data collected by Rosetta last night and which will be analysed over the coming days and weeks will finally unveil the true nature of Steins. Through the study of minor bodies such as asteroids, Rosetta is opening up a new window onto the early history of our Solar System. It will give us a better understanding of the origins and evolution of the planets, and also a key to better interpreting asteroid data collected from the ground. Under Rosetta's scope This

  14. The hazard of near-Earth asteroid impacts on earth

    Science.gov (United States)

    Chapman, Clark R.

    2004-05-01

    Near-Earth asteroids (NEAs) have struck the Earth throughout its existence. During epochs when life was gaining a foothold ˜4 Ga, the impact rate was thousands of times what it is today. Even during the Phanerozoic, the numbers of NEAs guarantee that there were other impacts, possibly larger than the Chicxulub event, which was responsible for the Cretaceous-Tertiary extinctions. Astronomers have found over 2500 NEAs of all sizes, including well over half of the estimated 1100 NEAs >1 km diameter. NEAs are mostly collisional fragments from the inner half of the asteroid belt and range in composition from porous, carbonaceous-chondrite-like to metallic. Nearly one-fifth of them have satellites or are double bodies. When the international telescopic Spaceguard Survey, which has a goal of discovering 90% of NEAs >1 km diameter, is completed, perhaps as early as 2008, nearly half of the remaining impact hazard will be from land or ocean impacts by bodies 70-600 m diameter. (Comets are expected to contribute only about 1% of the total risk.) The consequences of impacts for civilization are potentially enormous, but impacts are so rare that worldwide mortality from impacts will have dropped to only about 150 per year (averaged over very long durations) after the Spaceguard goal has, presumably, ruled out near-term impacts by 90% of the most dangerous ones; that is, in the mid-range between very serious causes of death (disease, auto accidents) and minor but frightening ones (like shark attacks). Differences in perception concerning this rather newly recognized hazard dominate evaluation of its significance. The most likely type of impact events we face are hyped or misinterpreted predicted impacts or near-misses involving small NEAs.

  15. Comets and How to Observe Them

    CERN Document Server

    Schmude, Richard

    2010-01-01

    Comets have inspired wonder, excitement and even fear ever since they were first observed. They contain material from early in the life of the Solar System, held in deep-freeze. This makes them key in our understanding of the formation and evolution of many Solar System bodies. Recent ground- and space-based observations have changed much in our understanding of comets. Comets and How to Observe Them gives a summary of our current knowledge and describes how amateur astronomers can contribute to the body of scientific knowledge of comets. This book contains many practical examples of how to construct comet light-curves, measure how fast a comet’s coma expands, and determine the rotation period of the nucleus. All these examples are illustrated with drawings and photographs.

  16. Hydrodynamic Modeling of the Deep Impact Mission into Comet Tempel 1

    Science.gov (United States)

    Sorli, Kya; Remington, Tané; Bruck Syal, Megan

    2018-01-01

    Kinetic impact is one of the primary strategies to deflect hazardous objects off of an Earth-impacting trajectory. The only test of a small-body impact is the 2005 Deep Impact mission into comet Tempel 1, where a 366-kg mass impactor collided at ~10 km/s into the comet, liberating an enormous amount of vapor and ejecta. Code comparisons with observations of the event represent an important source of new information about the initial conditions of small bodies and an extraordinary opportunity to test our simulation capabilities on a rare, full-scale experiment. Using the Adaptive Smoothed Particle Hydrodynamics (ASPH) code, Spheral, we explore how variations in target material properties such as strength, composition, porosity, and layering affect impact results, in order to best match the observed crater size and ejecta evolution. Benchmarking against this unique small-body experiment provides an enhanced understanding of our ability to simulate asteroid or comet response to future deflection missions. 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-739336-DRAFT.

  17. PF191012 Myszyniec - highest Orionid meteor ever recorded

    Science.gov (United States)

    Olech, A.; Żołaḑek, P.; Wiśniewski, M.; Fietkiewicz, K.; Maciejewski, M.; Tymiński, Z.; Krzyżanowski, T.; Krasnowski, M.; Kwinta, M.; Myszkiewicz, M.; Polakowski, K.; Zarȩba, P.

    2013-09-01

    On the night of Oct. 18/19, 2012, at 00:23 UT, a -14.7 mag Orionid fireball occurred over northeastern Poland. The precise orbit and atmospheric trajectory of the event are presented, based on the data collected by five video stations and one photographic Polish Fireball Network station. The beginning height of the meteor is 168.4 ± 0.6 km, which makes the PF191012 Myszyniec fireball the highest ever observed, well-documented meteor not belonging to the Leonid shower. The ablation became the dominant source of light of the meteor at a height of around 115 km. The thermalization of sputtered particles is suggested to be the source of radiation above that value. The transition height of 115 km is 10-15 km below the transition heights derived for Leonids and might suggest that the material of Leonids is more fragile and probably has smaller bulk density than that of Orionids.

  18. Temporal and Spatial Variation of Meteor Flux in Radio Data

    Science.gov (United States)

    Powell, Charles; Veljkovicl, Kristina

    2017-08-01

    The variation of hourly detection counts from almost 350 radio meteor detection stations is analysed to determine the effect of year, time of day, and latitude on observations, as well as discussions of annual and monthly variations. Results indicate a significant increase in hourly detection counts in 2009-2010, supporting previous hypotheses of correlation between radio meteor detection rates and solar activity. Annual increases in meteor rates during summer months are noted, with no clear explanation. Monthly variations are not significant. The effect of latitude on detection counts is significant for years 2005-2016. For 12 of 17 considered years, night-time detection counts are greater than day-time counts, likely due to changes in ionospheric structure at night.

  19. French Meteor Network for High Precision Orbits of Meteoroids

    Science.gov (United States)

    Atreya, P.; Vaubaillon, J.; Colas, F.; Bouley, S.; Gaillard, B.; Sauli, I.; Kwon, M. K.

    2011-01-01

    There is a lack of precise meteoroids orbit from video observations as most of the meteor stations use off-the-shelf CCD cameras. Few meteoroids orbit with precise semi-major axis are available using film photographic method. Precise orbits are necessary to compute the dust flux in the Earth s vicinity, and to estimate the ejection time of the meteoroids accurately by comparing them with the theoretical evolution model. We investigate the use of large CCD sensors to observe multi-station meteors and to compute precise orbit of these meteoroids. An ideal spatial and temporal resolution to get an accuracy to those similar of photographic plates are discussed. Various problems faced due to the use of large CCD, such as increasing the spatial and the temporal resolution at the same time and computational problems in finding the meteor position are illustrated.

  20. On the period of the Geminid meteor stream

    International Nuclear Information System (INIS)

    Jones, J.

    1978-01-01

    A new method has been devised for analysing the periodicities from year to year in meteor-shower activity. This appears to give more reproducible results than have been previously obtained and the orbital period of Geminid radio meteors is found to be close to 1.49 yr, a value consistent with the decrease in period of faint meteors and also with the systematic change of solar longitude at maximum shower activity with decreasing meteoroid size. When interpreted in terms of the Poynting-Robertson effect, these data indicate a stream age of 4.7 x 10 3 yr which is sufficiently long to explain the lack of very large concentrations of particles in the stream. (author)

  1. An Automatic Video Meteor Observation Using UFO Capture at the Showa Station

    Science.gov (United States)

    Fujiwara, Y.; Nakamura, T.; Ejiri, M.; Suzuki, H.

    2012-05-01

    The goal of our study is to clarify meteor activities in the southern hemi-sphere by continuous optical observations with video cameras with automatic meteor detection and recording at Syowa station, Antarctica.

  2. C/2013 P2 Pan STARRS - The Manx Comet

    Science.gov (United States)

    Meech, Karen J.; Yang, Bin; Keane, Jacqueline; Hainaut, Olivier; Kleyna, Jan; Hsieh, Henry; Bauer, James; Wainscoat, Richard; Veres, Peter

    2014-11-01

    On Aug 4, 2013 an apparently asteroidal object was discovered by the Pan STARRS1 (PS1) survey telescope on Haleakala at magnitude 20.4 (corresponding to a nucleus radius between 1.4-2.9 km for albedos between 0.25-0.04). PS1 pre-recovery images taken on July 26 and on Aug. 3 allowed a good orbit to be determined. The orbit looks like that of a long-period comet with a semi major axis of 2720 AU and an eccentricity of 0.999. Shortly following the discovery, reports from small telescopes came in that there was low level activity associated with this object (at r = 3.45 AU), and the object was designated P/2013 P2 (Pan STARRS). The activity was not seen in images obtained with PS1, the Faulkes N telescope or the CFHT 3.6m, however the object was passing through a region of significant nebulosity. Deep images obtained on the CFHT on Aug. 8 and follow up images obtained with the Gemini North 8m telescope on Sep. 9 showed a very faint tail extending a few arcsec to PA=45 deg (inconsistent with the earlier reports). The object was observed using several facilities up until solar conjunction, and again after perihelion (Feb. 17, 2014) in March, with little increase in activity. A search of the NEOWISE archives show no detection during the cryogenic and immediate pos-cryogenic phases, so we can only place an upper limit on the nucleus size from these data. An object on a long-period comet orbit at this heliocentric distance typically should be very active, and our team hypothesized that this could either be a nearly-extinct comet or possibly inner solar system material ejected to the outer solar system during planet migration as predicted by various dynamical models. To distinguish between these scenarios, we obtained both optical and near-IR spectra of P/2013 P2 on 2014 May 7 and 21, when the object was at r=2.97 and 2.99 AU, respectively. Initial reductions show no emission lines. We will report on our spectra and imaging data, and discuss the implications for the origin

  3. Oort spike comets with large perihelion distances

    Science.gov (United States)

    Królikowska, Małgorzata; Dybczyński, Piotr A.

    2017-12-01

    The complete sample of large-perihelion nearly-parabolic comets discovered during the period 1901-2010 is studied, starting with their orbit determination. Next, an orbital evolution that includes three perihelion passages (previous-observed-next) is investigated in which a full model of Galactic perturbations and perturbations from passing stars is incorporated. We show that the distribution of planetary perturbations suffered by actual large-perihelion comets during their passage through the Solar system has a deep, unexpected minimum around zero, which indicates a lack of 'almost unperturbed' comets. Using a series of simulations we show that this deep well is moderately resistant to some diffusion of the orbital elements of the analysed comets. It seems reasonable to assert that the observed stream of these large-perihelion comets experienced a series of specific planetary configurations when passing through the planetary zone. An analysis of the past dynamics of these comets clearly shows that dynamically new comets can appear only when their original semimajor axes are greater than 20 000 au. On the other hand, dynamically old comets are completely absent for semimajor axes longer than 40 000 au. We demonstrate that the observed 1/aori-distribution exhibits a local minimum separating dynamically new from dynamically old comets. Long-term dynamical studies reveal a wide variety of orbital behaviour. Several interesting examples of the action of passing stars are also described, in particular the impact of Gliese 710, which will pass close to the Sun in the future. However, none of the obtained stellar perturbations is sufficient to change the dynamical status of the analysed comets.

  4. ``Hands-Free'' Asteroid Astrometry

    Science.gov (United States)

    Monet, A. K. B.; Bowell, E.; Monet, D. G.

    1997-12-01

    How do you undertake a major new astrometric program with no additional financial or personnel resources? The answer: automation! Early in 1992, the authors began a collaboration to obtain astrometric positions for several classes of asteroids (V_lim 17.5 mag) whose orbits required improvement or that were otherwise of special interest. The telescope used for this work is the USNOFS 0.2-meter transit telescope, equipped with a CCD camera. The operation of this instrument has been fully automated (Stone, et al. 1996, AJ, 111, 1721. Nightly observing rosters are constructed from a ranked listing of all asteroids of interest, prepared each month by Bowell. In a typical month, about 200 observations are made, although this number can range from 0 to over 400. Reductions are done automatically as well. A typical 10-hr nightly run can be fully reduced in less than 1/2 hr. Reductions are made on a frame-by-frame basis and positions of the asteroids computed with respect to the USNO-A1.0 catalog (Monet, D.G. 1996, USNO-A1.0 Catalog -- 10 CD-ROM Set, US Naval Observatory.) Observational quality is checked by Bowell, who also recomputes orbits and reports final results to the Minor Planet Center. Orbit residuals hover around 0.3 arcsec. This poster will present a brief overview of the observing and analysis methods, an account of the first five years of results, and a description of planned improvements in instrumentation and analysis techniques.

  5. Binary asteroid population. 1. Angular momentum content

    Czech Academy of Sciences Publication Activity Database

    Pravec, Petr; Harris, A. W.

    2007-01-01

    Roč. 190, č. 1 (2007), s. 250-259 ISSN 0019-1035 R&D Projects: GA ČR(CZ) GA205/05/0604 Institutional research plan: CEZ:AV0Z10030501 Keywords : asteroids * satellites of asteroids Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 2.869, year: 2007

  6. [Asteroid hyalopathy (benson's disease): about a case].

    Science.gov (United States)

    Bienvenu, Yogolelo Asani; Angel, Musau Nkola; Leon, Kabamba Ngombe; Socrate, Kapalu Mwangala; Bruno, Iye Ombamba Kayimba; Gaby, Chenge Borasisi

    2017-01-01

    We here report a case of a 58 year-old diabetic male patient with asteroid hyalopathy, an affection rarely described in the literature. This study can help focus the attention of scientists on the pathologies of the vitreous disorders in diabetic patients as well as on other systemic diseases asteroid hyalopathy may be associated with.

  7. 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...

  8. Asteroid Impact & Deflection Assessment mission: Kinetic impactor

    Czech Academy of Sciences Publication Activity Database

    Cheng, A.F.; Michel, R.; Jutzi, M.; Rivkin, A. S.; Stickle, A.; Barnouin, O.; Ernst, C.; Atchison, J.; Pravec, Petr; Richardson, D.C.

    2016-01-01

    Roč. 121, February (2016), s. 25-37 ISSN 0032-0633 Institutional support: RVO:67985815 Keywords : planetary defense * near-Earth asteroids * asteroid impact hazards Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 1.892, year: 2016

  9. Asteroid-Deepsky Appulses in 2018

    Science.gov (United States)

    Warner, Brian D.

    2018-01-01

    The following list is a very small subset of the results of a search for asteroid-deepsky appulses for 2018, presenting only the highlights for the year based on close approaches of brighter asteroids to brighter DSOs. The complete set of predictions is available at http://www.minorplanet.info/ObsGuides/Appulses/DSOAppulses.htm

  10. Orbital Mechanics near a Rotating Asteroid

    Indian Academy of Sciences (India)

    2016-01-27

    Jan 27, 2016 ... 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 ...

  11. Modeling of lightcurves of binary asteroids

    Czech Academy of Sciences Publication Activity Database

    Scheirich, Peter; Pravec, Petr

    2009-01-01

    Roč. 200, č. 2 (2009), s. 531-547 ISSN 0019-1035 R&D Projects: GA ČR(CZ) GA205/05/0604 Institutional research plan: CEZ:AV0Z10030501 Keywords : asteroids * photometry * satellites of asteroids Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 3.340, year: 2009

  12. Lightcurve Photometry of Six Asteroids

    Science.gov (United States)

    Ferrero, Andrea

    2012-07-01

    Observations from 2012 January to March lead to the determination of the rotation periods for six main-belt asteroids: 33 Polyhymnia, P = 18.604 ± 0.004 h; 467 Laura, P = 37.4 ± 0.1 h; 825 Tanina, P = 6.940 ± 0.001 h; 1421 Esperanto, P = 21.982 ± 0.005 h; 3481 Xianglupeak, P = 5.137 ± 0.003 h; and 4350 Shibecha, which had two possible solutions, P = 2.890 ± 0.001 h and P = 5.778 ± 0.002 h.

  13. Absence of satellites of asteroids

    International Nuclear Information System (INIS)

    Gehrels, T.; Drummond, J.D.; Levenson, N.A.

    1987-01-01

    The absence of satellites within 0.1-7.0 arcmin of minor planets noted in the present CCD imaging survey is judged consistent with previous theoretical studies of collisions in which it is held that satellites would have to be larger than about 30 km in order to be collisionally stable. In view of tidal stability, the only main belt asteroid satellites which could conceivably possess stability over eons are near-contact binaries. Any recent collisional debris would be chaotic and collisionally unstable. 15 references

  14. Basic targeting strategies for rendezvous and flyby missions to the near-Earth asteroids

    Science.gov (United States)

    Perozzi, Ettore; Rossi, Alessandro; Valsecchi, Giovanni B.

    2001-01-01

    Missions to asteroids and comets are becoming increasingly feasible both from a technical and a financial point of view. In particular, those directed towards the Near-Earth Asteroids have proven suitable for a low-cost approach, thus attracting the major space agencies as well as private companies. The choice of a suitable target involves both scientific relevance and mission design considerations, being often a difficult task to accomplish due to the limited energy budget at disposal. The aim of this paper is to provide an approach to basic trajectory design which allows to account for both aspects of the problem, taking into account scientific and technical information. A global characterization of the Near-Earth Asteroids population carried out on the basis of their dynamics, physical properties and flight dynamics considerations, allows to identify a group of candidates which satisfy both, the scientific and engineering requirements. The feasibility of rendezvous and flyby missions towards them is then discussed and the possibility of repeated encounters with the same object is investigated, as an intermediate scenario. Within this framework, the capability of present and near future launch and propulsion systems for interplanetary missions is also addressed.

  15. Meteor observation from space - The Smart Panoramical Optical Sensor (SPOSH)

    Science.gov (United States)

    Koschny, D.; di Martino, M.; Oberst, J.

    The European Space Agency (ESA) is funding two parallel studies for a ``Smart Panoramic Optical Head''. The main goal is to develop the technology for a space-qualified, very light-sensitive camera with a wide field of view, both from the hardware and the software side. The scientific application is to allow imaging of phenomena on the dark side of planets or moons, e.g. lightning flashes from thunderstorms or electrical discharges in sand storms, meteors, impact flashes, aurorae, etc. This paper will concentrate on the potential of this camera for the study of meteors from an orbit around a planet.

  16. Physics-Based Modeling of Meteor Entry and Breakup

    Science.gov (United States)

    Prabhu, Dinesh K.; Agrawal, Parul; Allen, Gary A., Jr.; Bauschlicher, Charles W., Jr.; Brandis, Aaron M.; Chen, Yih-Kang; Jaffe, Richard L.; Palmer, Grant E.; Saunders, David A.; Stern, Eric C.; hide

    2015-01-01

    A new research effort at NASA Ames Research Center has been initiated in Planetary Defense, which integrates the disciplines of planetary science, atmospheric entry physics, and physics-based risk assessment. This paper describes work within the new program and is focused on meteor entry and breakup.Over the last six decades significant effort was expended in the US and in Europe to understand meteor entry including ablation, fragmentation and airburst (if any) for various types of meteors ranging from stony to iron spectral types. These efforts have produced primarily empirical mathematical models based on observations. Weaknesses of these models, apart from their empiricism, are reliance on idealized shapes (spheres, cylinders, etc.) and simplified models for thermal response of meteoritic materials to aerodynamic and radiative heating. Furthermore, the fragmentation and energy release of meteors (airburst) is poorly understood.On the other hand, flight of human-made atmospheric entry capsules is well understood. The capsules and their requisite heatshields are designed and margined to survive entry. However, the highest speed Earth entry for capsules is 13 kms (Stardust). Furthermore, Earth entry capsules have never exceeded diameters of 5 m, nor have their peak aerothermal environments exceeded 0.3 atm and 1 kW/sq cm. The aims of the current work are: (i) to define the aerothermal environments for objects with entry velocities from 13 to 20 kms; (ii) to explore various hypotheses of fragmentation and airburst of stony meteors in the near term; (iii) to explore the possibility of performing relevant ground-based tests to verify candidate hypotheses; and (iv) to quantify the energy released in airbursts. The results of the new simulations will be used to anchor said risk assessment analyses. With these aims in mind, state-of-the-art entry capsule design tools are being extended for meteor entries. We describe: (i) applications of current simulation tools to

  17. An Operational Autonomous Meteor Detector: Development Issues and Early Results

    Science.gov (United States)

    Gural, P. S.

    1997-06-01

    A real-time computer-based meteor detector has been in operation by the author in the United States since February 1997. Operating in a completely autonomous mode it has successfully detected several meteors, numerous artificial satellites, and aircraft since its inception. Since the computer system is based on an Intel 486 microprocessor and operates at half the pixel resolution available from a CCD camera, it is believed with the faster computers on the market today, a full resolution system is realizable. A proposal to fund the building of such a system is in the works at this time.

  18. The METEOR trial: no rush to repair a torn meniscus.

    Science.gov (United States)

    Hwang, Yong Gil; Kwoh, C Kent

    2014-04-01

    It is uncertain whether arthroscopic partial meniscectomy is better than physical therapy in patients who have a symptomatic torn meniscus on top of osteoarthritis of the knee. The Meniscal Repair in Osteoarthritis Research (METEOR) trial concluded that physical therapy is acceptable at first, and that surgery is not routinely needed. In patients assigned to physical therapy who eventually needed surgery, the delay resulting from a trial of conservative management did not impair outcomes at 12 months from the initial presentation. Here, we analyze the background, design, findings, and clinical implications of the METEOR trial.

  19. The asteroids as outcomes of catastrophic collisions

    Energy Technology Data Exchange (ETDEWEB)

    Farinella, P. (Osservatorio Astronomico di Brera, Merate, Italy); Paolicchi, P.

    1982-12-01

    The role of catastrophic collisions in the evoloution of the asteroids is discussed in detail, employing extrapolations of experimental results on the outcome of high velocity-impacts. The probability of impacts with a given projectile-to-target mass ratio for asteroids of different sizes is derived, taking into account different mass distributions of the asteroid population at the beginning of the collision process. The extrapolations show that collisional breakup against solid-state cohesions must be a widespread process for asteroids. The influence of self-gravitation and transfer of angular momentum during collision is shown to depend strongly on the traget size, resulting in a variety of possible outcomes in the intermediate size range. Comparason of the theoretical results with observations of asteroid rotations and shapes yields favorable results.

  20. OpenComet: An automated tool for comet assay image analysis

    Directory of Open Access Journals (Sweden)

    Benjamin M. Gyori

    2014-01-01

    Full Text Available Reactive species such as free radicals are constantly generated in vivo and DNA is the most important target of oxidative stress. Oxidative DNA damage is used as a predictive biomarker to monitor the risk of development of many diseases. The comet assay is widely used for measuring oxidative DNA damage at a single cell level. The analysis of comet assay output images, however, poses considerable challenges. Commercial software is costly and restrictive, while free software generally requires laborious manual tagging of cells. This paper presents OpenComet, an open-source software tool providing automated analysis of comet assay images. It uses a novel and robust method for finding comets based on geometric shape attributes and segmenting the comet heads through image intensity profile analysis. Due to automation, OpenComet is more accurate, less prone to human bias, and faster than manual analysis. A live analysis functionality also allows users to analyze images captured directly from a microscope. We have validated OpenComet on both alkaline and neutral comet assay images as well as sample images from existing software packages. Our results show that OpenComet achieves high accuracy with significantly reduced analysis time.