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Sample records for barringer meteor crater

  1. Creation of High Resolution Terrain Models of Barringer Meteorite Crater (Meteor Crater) Using Photogrammetry and Terrestrial Laser Scanning Methods

    Science.gov (United States)

    Brown, Richard B.; Navard, Andrew R.; Holland, Donald E.; McKellip, Rodney D.; Brannon, David P.

    2010-01-01

    Barringer Meteorite Crater or Meteor Crater, AZ, has been a site of high interest for lunar and Mars analog crater and terrain studies since the early days of the Apollo-Saturn program. It continues to be a site of exceptional interest to lunar, Mars, and other planetary crater and impact analog studies because of its relatively young age (est. 50 thousand years) and well-preserved structure. High resolution (2 meter to 1 decimeter) digital terrain models of Meteor Crater in whole or in part were created at NASA Stennis Space Center to support several lunar surface analog modeling activities using photogrammetric and ground based laser scanning techniques. The dataset created by this activity provides new and highly accurate 3D models of the inside slope of the crater as well as the downslope rock distribution of the western ejecta field. The data are presented to the science community for possible use in furthering studies of Meteor Crater and impact craters in general as well as its current near term lunar exploration use in providing a beneficial test model for lunar surface analog modeling and surface operation studies.

  2. 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

  3. Investigation of impact materials around Barringer Meteor Crater by SEM-EDX and micro-PIXE techniques

    International Nuclear Information System (INIS)

    Uzonyi, I.; Szoeor, Gy.; Rozsa, P.; Pelicon, P.; Simcic, J.; Cserhati, C.; Daroczi, L.; Kiss, A.Z.

    2009-01-01

    Impact materials collected at the Barringer Meteor Crater have been characterized by SEM-EDX and micro-PIXE techniques. Fine textural and true elemental images were created. As a main feature silica-bearing shell and an S-Fe-Ni-Cu core could be distinguished. Three different types of S-Fe-Ni-Cu systems were identified such as chalcopyrite, pentlandite and pyrrhotite.

  4. Investigation of impact materials from the Barringer Meteor Crater by micro-XANES and micro-PIXE techniques

    International Nuclear Information System (INIS)

    Szikszai, Z.; Uzonyi, I.; Kiss, A.Z.; Sziki, G.A.; Vantelon, D.; Rozsa, P.

    2009-01-01

    Impact materials from the Barringer Meteor Crater were examined by combined micro-X-ray absorption near edge structure (micro-XANES) and micro-particle induced X-ray emission (micro-PIXE) methods. Efforts were focussed on the complex characterization of their iron-rich inclusions. The lateral distribution of elements as well as the oxidation state of iron was determined. The study demonstrates the capabilities of chemical speciation screening based on energy selective micro-XRF maps in geology. With the help of this method zero-valent (metallic) and three-valent iron were excluded in the studied specimens without performing XANES in every pixel.

  5. Characterization of impact materials around Barringer Meteor Crater by micro-PIXE and micro-SRXRF techniques

    International Nuclear Information System (INIS)

    Uzonyi, I.; Szoeor, Gy.; Rozsa, P.; Vekemans, B.; Vincze, L.; Adams, F.; Drakopoulos, M.; Somogyi, A.; Kiss, A.Z.

    2004-01-01

    A combined micro-PIXE and micro-SRXRF method has been tested successfully for the characterization of impact materials collected at the well-known Barringer Meteor Crater. The micro-PIXE technique proved to be sensitive in the Z≤28 atomic number region while the micro-SRXRF above Fe especially for the siderophile elements. Quantitative analysis has become available for about 40 elements by these complementary methods providing new perspectives for the interpretation of the formation mechanism of impact metamorphosed objects

  6. 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.

  7. Two-dimensional computer simulation of hypervelocity impact cratering: some preliminary results for Meteor Crater, Arizona

    Energy Technology Data Exchange (ETDEWEB)

    Bryan, J.B.; Burton, D.E.; Cunningham, M.E.; Lettis, L.A. Jr.

    1978-04-01

    A computational approach used for subsurface explosion cratering has been extended to hypervelocity impact cratering. Meteor (Barringer) Crater, Arizona, was selected for our first computer simulation because it was the most thoroughly studied. It is also an excellent example of a simple, bowl-shaped crater and is one of the youngest terrestrial impact craters. Shoemaker estimates that the impact occurred about 20,000 to 30,000 years ago (Roddy (1977)). Initial conditions for this calculation included a meteorite impact velocity of 15 km/s. meteorite mass of 1.57E + 08 kg, with a corresponding kinetic energy of 1.88E + 16 J (4.5 megatons). A two-dimensional Eulerian finite difference code called SOIL was used for this simulation of a cylindrical iron projectile impacting at normal incidence into a limestone target. For this initial calculation a Tillotson equation-of-state description for iron and limestone was used with no shear strength. A color movie based on this calculation was produced using computer-generated graphics. Results obtained for this preliminary calculation of the formation of Meteor Crater, Arizona, are in good agreement with Meteor Crater Measurements.

  8. Two-dimensional computer simulation of hypervelocity impact cratering: some preliminary results for Meteor Crater, Arizona

    International Nuclear Information System (INIS)

    Bryan, J.B.; Burton, D.E.; Cunningham, M.E.; Lettis, L.A. Jr.

    1978-04-01

    A computational approach used for subsurface explosion cratering has been extended to hypervelocity impact cratering. Meteor (Barringer) Crater, Arizona, was selected for our first computer simulation because it was the most thoroughly studied. It is also an excellent example of a simple, bowl-shaped crater and is one of the youngest terrestrial impact craters. Shoemaker estimates that the impact occurred about 20,000 to 30,000 years ago [Roddy (1977)]. Initial conditions for this calculation included a meteorite impact velocity of 15 km/s. meteorite mass of 1.57E + 08 kg, with a corresponding kinetic energy of 1.88E + 16 J (4.5 megatons). A two-dimensional Eulerian finite difference code called SOIL was used for this simulation of a cylindrical iron projectile impacting at normal incidence into a limestone target. For this initial calculation a Tillotson equation-of-state description for iron and limestone was used with no shear strength. A color movie based on this calculation was produced using computer-generated graphics. Results obtained for this preliminary calculation of the formation of Meteor Crater, Arizona, are in good agreement with Meteor Crater Measurements

  9. Two-dimensional computer simulation of hypervelocity impact cratering: some preliminary results for Meteor Crater, Arizona

    Energy Technology Data Exchange (ETDEWEB)

    Bryan, J.B.; Burton, D.E.; Cunningham, M.E.; Lettis, L.A. Jr.

    1978-06-01

    A computational approach used for subsurface explosion cratering was extended to hypervelocity impact cratering. Meteor (Barringer) Crater, Arizona, was selected for the first computer simulation because it is one of the most thoroughly studied craters. It is also an excellent example of a simple, bowl-shaped crater and is one of the youngest terrestrial impact craters. Initial conditions for this calculation included a meteorite impact velocity of 15 km/s, meteorite mass of 1.67 x 10/sup 8/ kg, with a corresponding kinetic energy of 1.88 x 10/sup 16/ J (4.5 megatons). A two-dimensional Eulerian finite difference code called SOIL was used for this simulation of a cylindrical iron projectile impacting at normal incidence into a limestone target. For this initial calculation, a Tillotson equation-of-state description for iron and limestone was used with no shear strength. Results obtained for this preliminary calculation of the formation of Meteor Crater are in good agreement with field measurements. A color movie based on this calculation was produced using computer-generated graphics. 19 figures, 5 tables, 63 references.

  10. Two-dimensional computer simulation of hypervelocity impact cratering: some preliminary results for Meteor Crater, Arizona

    International Nuclear Information System (INIS)

    Bryan, J.B.; Burton, D.E.; Cunningham, M.E.; Lettis, L.A. Jr.

    1978-06-01

    A computational approach used for subsurface explosion cratering was extended to hypervelocity impact cratering. Meteor (Barringer) Crater, Arizona, was selected for the first computer simulation because it is one of the most thoroughly studied craters. It is also an excellent example of a simple, bowl-shaped crater and is one of the youngest terrestrial impact craters. Initial conditions for this calculation included a meteorite impact velocity of 15 km/s, meteorite mass of 1.67 x 10 8 kg, with a corresponding kinetic energy of 1.88 x 10 16 J (4.5 megatons). A two-dimensional Eulerian finite difference code called SOIL was used for this simulation of a cylindrical iron projectile impacting at normal incidence into a limestone target. For this initial calculation, a Tillotson equation-of-state description for iron and limestone was used with no shear strength. Results obtained for this preliminary calculation of the formation of Meteor Crater are in good agreement with field measurements. A color movie based on this calculation was produced using computer-generated graphics. 19 figures, 5 tables, 63 references

  11. Micro-XANES and micro-PIXE measurements of iron-rich impact materials from the Barringer Crater

    International Nuclear Information System (INIS)

    Szikszai, Z.; Uzonyi, I.; Kiss, A.Z.; Sziki, G.A.; Rozsa, P.

    2009-01-01

    Complete text of publication follows. Barringer Crater, also known as Meteor Crater, in Northern Central Arizona was the first recognized impact crater on Earth. It was created about 50,000 years ago by an iron asteroid. A small portion of the incoming asteroid survived in the form of solid fragments, but most of the asteroid material were dispersed. During our previous investigations, impact material from the Barringer Crater was examined with various nuclear analytical techniques. These powerful tools are dedicated to the study of the elemental composition of the samples and the distribution of elements but do not give access to the chemical state of these elements. However, by combining micro-X-ray Absorption Near Edge Structure (XANES) and micro-Synchrotron X-Ray Fluorescence (SXRF) both the distribution of the elements and their chemical state can be determined. The main aim of the present study was to investigate the valence states of iron [Fe(III), Fe(II), Fe metal] to obtain additional information about the impact processes forming the Barringer Crater. The samples (tiny magnetic objects) were embedded in artificial resin and polished to get a flat surface. They were covered with a thin carbon layer for pre-selection using electron microprobe. The micro-XANES and micro- XRF measurements were carried out on the LUCIA beamline at SLS with a beam focused to a 4 x 10 μm 2 spot. XANES spectra were obtained by recording the Fe K α fluorescence intensity as a function of the incident beam energy over a range of 7.0-7.2 keV. Five samples served as standards with known proportion of chemical states of iron. After determining the position of the pre-edge peaks in the spectra of these minerals, a calibration curve was plotted for estimating the Fe(III)/Σ Fe ratio in unknown samples. Chemical speciation screening was also following the method described in [4]. X-ray fluorescence maps were recorded at four different excitation energies, reflecting the differences of

  12. 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.

  13. Ground penetrating radar geologic field studies of the ejecta of Barringer Meteorite Crater, Arizona, as a planetary analog

    Science.gov (United States)

    Russell, Patrick S.; Grant, John A.; Williams, Kevin K.; Carter, Lynn M.; Brent Garry, W.; Daubar, Ingrid J.

    2013-09-01

    penetrating radar (GPR) has been a useful geophysical tool in investigating a variety of shallow subsurface geological environments on Earth. Here we investigate the capabilities of GPR to provide useful geologic information in one of the most common geologic settings of planetary surfaces, impact crater ejecta. Three types of ejecta are surveyed with GPR at two wavelengths (400 MHz, 200 MHz) at Meteor Crater, Arizona, with the goal of capturing the GPR signature of the subsurface rock population. In order to "ground truth" the GPR characterization, subsurface rocks are visually counted and measured in preexisting subsurface exposures immediately adjacent to and below the GPR transect. The rock size-frequency distribution from 10 to 50 cm based on visual counts is well described by both power law and exponential functions, the former slightly better, reflecting the control of fragmentation processes during the impact-ejection event. GPR counts are found to overestimate the number of subsurface rocks in the upper meter (by a factor of 2-3x) and underestimate in the second meter of depth (0.6-1.0x), results attributable to the highly scattering nature of blocky ejecta. Overturned ejecta that is fractured yet in which fragments are minimally displaced from their complement fragments produces fewer GPR returns than well-mixed ejecta. The use of two wavelengths and division of results into multiple depth zones provides multiple aspects by which to characterize the ejecta block population. Remote GPR measurement of subsurface ejecta in future planetary situations with no subsurface exposure can be used to characterize those rock populations relative to that of Meteor Crater.

  14. 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.

  15. Planetary science: Meteor Crater formed by low-velocity impact.

    Science.gov (United States)

    Melosh, H J; Collins, G S

    2005-03-10

    Meteor Crater in Arizona was the first terrestrial structure to be widely recognized as a meteorite impact scar and has probably been more intensively studied than any other impact crater on Earth. We have discovered something surprising about its mode of formation--namely that the surface-impact velocity of the iron meteorite that created Meteor Crater was only about 12 km s(-1). This is close to the 9.4 km s(-1) minimum originally proposed but far short of the 15-20 km s(-1) that has been widely assumed--a realization that clears up a long-standing puzzle about why the crater does not contain large volumes of rock melted by the impact.

  16. Fractal Fragmentation triggered by meteor impact: The Ries Crater (Germany)

    Science.gov (United States)

    Paredes Marino, Joali; Perugini, Diego; Rossi, Stefano; Kueppers, Ulrich

    2015-04-01

    FRACTAL FRAGMENTATION TRIGGERED BY METEOR IMPACT: THE RIES CRATER (GERMANY) Joali Paredes (1), Stefano Rossi (1), Diego Perugini (1), Ulrich Kueppers (2) 1. Department of Physics and Geology, University of Perugia, Italy 2. Department of Earth and Environmental Sciences, University of Munich, Germany The Nördlinger Ries is a large circular depression in western Bavaria, Germany. The depression was caused by a meteor impact, which occurred about 14.3 million-14.5 million years ago. The original crater rim had an estimated diameter of 24 kilometers. Computer modeling of the impact event indicates that the impact or probably had diameters of about 1.5 kilometers and impacted the target area at an angle around 30 to 50 degrees from the surface in a west- southwest to east-northeast direction. The impact velocity is thought to have been about 20 km/s. The meteor impact generated extensive fragmentation of preexisting rocks. In addition, melting of these rocks also occurred. The impact melt was ejected at high speed provoking its extensive fragmentation. Quenched melt fragments are ubiquitous in the outcrops. Here we study melt fragment size distributions with the aim of understanding the style of melt fragmentation during ejection and to constrain the rheological properties of such melts. Digital images of suevite (i.e. the rock generated after deposition and diagenesis of ash and fragments produced by the meteor impact) were obtained using a high-resolution optical scanner. Successively, melt fragments were traced by image analysis and the images segmented in order to obtain binary images on which impact melt fragments are in black color, embedded on a white background. Hence, the size of fragments was determined by image analysis. Fractal fragmentation theory has been applied to fragment size distributions of melt fragments in the Ries crater. Results indicate that melt fragments follow fractal distributions indicating that fragmentation of melt generated by the

  17. In situ 10Be-26Al exposure ages at Meteor Crater, Arizona

    Science.gov (United States)

    Nishiizumi, K.; Kohl, C.P.; Shoemaker, E.M.; Arnold, J.R.; Klein, J.; Fink, D.; Middleton, R.

    1991-01-01

    A new method of dating the surface exposure of rocks from in situ production of 10Be and 26Al has been applied to determine the age of Meteor Crater, Arizona. A lower bound on the crater age of 49,200 ?? 1,700 years has been obtained by this method. ?? 1991.

  18. Siderophile element fractionation in meteor crater impact glasses and metallic spherules

    Science.gov (United States)

    Mittlefehldt, David W.; See, T. H.; Scott, E. R. D.

    1993-01-01

    Meteor Crater, Arizona provides an opportunity to study, in detail, elemental fractionation processes occurring during impacts through the study of target rocks, meteorite projectile and several types of impact products. We have performed EMPA and INAA on target rocks, two types of impact glass and metallic spherules from Meteor Crater. Using literature data for the well studied Canyon Diablo iron we can show that different siderophite element fractionations affected the impact glasses than affected the metallic spherules. The impact glasses primarily lost Au, while the metallic spherules lost Fe relative to other siderophile elements.

  19. Implementing planetary meteor impact craters as high gain radio frequency dish reflector antennas

    Science.gov (United States)

    Taylor, Travis S.

    Future ventures back to the Moon, Mars, or the outer planets and natural solar system objects would benefit fiom high bandwidth communications capabilities that enable faster data transfer rates to and fiom the spacecraft. However, communication links for such missions are limited by the antenna aperture size, transceiver power, and range between the space vehicle communications system and the receiving systems on Earth. This dissertation proposes a novel approach for using naturally occurring meteor impact craters as the parabolic dish reflector for radio frequency antennas. Analysis and experimentation shows that for long radio wavelengths that meteor impact craters appear very similar in geometry to dish antennas. There are many craters on the lunar surface that fit very closely to dish geometries. Some of these craters are as large as 100 kilometers in diameter. The calculated data transmission rate achievable from such an antenna configuration is many times greater than currently available long range space communications systems. Preliminary experiments conducted using manmade craters demonstrated the possibility of the concept. A 20 m diameter crater was dug and implemented in a complex radio telescope configuration with receiver systems at multiple wavelengths. The electronic components were all inexpensive hobbyist components or homemade. The radio telescope system was successful in detecting radio signals from the Sun and from the Crab Nebula. Sidereal motion of the astronomical sources matched exactly to the time lapse of the detected signals. Further analysis suggests that this concept could be implemented in near-term missions to the Moon with currently available technology. Analysis suggests that a spacecraft orbiting the Moon at 100 km altitude could use very large craters as reflector dishes. Terrestrial based experiments using impact craters like the one in Meteor Crater, Arizona could be conducted to determine the impact of soil reflectivity

  20. Meteor Crater: An Analog for Using Landforms to Reconstruct Past Hydrologic Conditions

    Science.gov (United States)

    Palucis, M. C.; Dietrich, W. E.; Howard, A. D.; Nishiizumi, K.; Caffee, M. W.; Kring, D. A.

    2015-12-01

    Recent work suggests that debris flow activity has occurred on Mars in the last few million years during high orbital obliquities, but estimating the amount and frequency of liquid water needed to generate these types of flows is still poorly constrained. While it is relatively common to estimate water amounts needed to produce landforms on Mars, such as gullies or alluvial fans, this is something rarely done on Earth. Consequently, there is little field data on the linkage between climate (snowmelt or rainfall events) and the amount of runoff needed to produce specific volumes of sediment in a landform. Here, we present field and modeling data from Meteor Crater, which is a ~50,000 year old impact crater in northern Arizona (USA). Though it is very well preserved, it has developed gullies along its inner wall, similar in form to many gullies on Mars. Meteor Crater, similar to many Martian craters, has also gone through a change in a climate based on the ~30 m of lake sediments on its now dry floor, and what has eroded from its walls has deposited on its floor, making it a closed system. We show using LiDAR-derived topographic data and field observations that debris flows, likely generated by runoff entrainment into talus bordering bedrock cliffs of the crater walls, drove erosion and deposition processes at Meteor Crater. Cosmogenic dating of levee deposits indicates that debris flows ceased in the early Holocene, synchronous with regional drying. For a water-to-rock ratio of 0.3 at the time of transport, which is based on data from rotating drum experiments, it would have taken ~150,000 m3 of water to transport the estimated ~500,000 m3 of debris flow deposits found at the surface of the crater floor. This extensive erosion would require less than 0.4 m of total runoff over the 0.35 km2 upslope source area of the crater, or ~26 mm of runoff per debris flow event. Much more runoff did occur however, as evidenced by lake deposits on the crater floor and Holocene

  1. Age and geomorphic history of Meteor Crater, Arizona, from cosmogenic 36Cl and 14C in rock varnish

    Science.gov (United States)

    Phillips, F.M.; Zreda, M.G.; Smith, S.S.; Elmore, D.; Kubik, P.W.; Dorn, R.I.; Roddy, D.J.

    1991-01-01

    Using cosmogenic 36Cl buildup and rock varnish radiocarbon, we have measured the exposure age of rock surfaces at Meteor Crater, Arizona. Our 36Cl measurements on four dolomite boulders ejected from the crater by the impact yield a mean age of 49.7 ?? 0.85 ka, which is in excellent agreement with an average age of 49 ?? 3 ka obtained from thermoluminescence studies on shock-metamorphosed dolomite and quartz. These ages are supported by undetectably low 14C in the oldest rock varnish sample. ?? 1991.

  2. Transformations to granular zircon revealed: Twinning, reidite, and ZrO2 in shocked zircon from Meteor Crater (Arizona, USA)

    Science.gov (United States)

    Cavosie, Aaron; Timms, Nicholas E.; Erickson, Timmons M.; Hagerty, Justin J.; Hörz, Friedrich

    2016-01-01

    Granular zircon in impact environments has long been recognized but remains poorly understood due to lack of experimental data to identify mechanisms involved in its genesis. Meteor Crater in Arizona (United States) contains abundant evidence of shock metamorphism, including shocked quartz, the high pressure polymorphs coesite and stishovite, diaplectic SiO2 glass, and lechatelierite (fused SiO2). Here we report the presence of granular zircon, a new shocked mineral discovery at Meteor Crater, that preserve critical orientation evidence of specific transformations that occurred during its formation at extreme impact conditions. The zircon grains occur as aggregates of sub-µm neoblasts in highly shocked Coconino Formation Sandstone (CFS) comprised of lechatelierite. Electron backscatter diffraction shows that each grain consists of multiple domains, some with boundaries disoriented by 65°, a known {112} shock-twin orientation. Other domains have crystallographic c-axes in alignment with {110} of neighboring domains, consistent with the former presence of the high pressure ZrSiO4 polymorph reidite. Additionally, nearly all zircon preserve ZrO2 + SiO2, providing evidence of partial dissociation. The genesis of CFS granular zircon started with detrital zircon that experienced shock-twinning and reidite formation from 20 to 30 GPa, ultimately yielding a phase that retained crystallographic memory; this phase subsequently recrystallized to systematically oriented zircon neoblasts, and in some areas partially dissociated to ZrO2. The lechatelierite matrix, experimentally constrained to form at >2000 °C, provided an ultra high-temperature environment for zircon dissociation (~1670 °C) and neoblast formation. The capacity of granular zircon to preserve a cumulative P-T record has not been recognized previously, and provides a new method for retrieving histories of impact-related mineral transformations in the crust at conditions far beyond which most rocks melt.

  3. Turkish meteor surveillance systems and network: Impact craters and meteorites database

    Science.gov (United States)

    Unsalan, O.; Ozel, M. E.; Derman, I. E.; Terzioglu, Z.; Kaygisiz, E.; Temel, T.; Topoyan, D.; Solmaz, A.; Yilmaz Kocahan, O.; Esenoglu, H. H.; Emrahoglu, N.; Yilmaz, A.; Yalcinkaya, B. O.

    2014-07-01

    In our project, we aim toward constructing Turkish Meteor Surveillance Systems and Network in Turkey. For this goal, video observational systems from SonotaCo (Japan) were chosen. Meteors are going to be observed with the specific cameras, their orbits will be calculated by the software from SonotaCo, and the places where they will be falling / impacting will be examined by field trips. The collected meteorites will be investigated by IR-Raman Spectroscopic techniques and SEM-EDX analyses in order to setup a database. On the other hand, according to our Prime Ministry Ottoman Archives, there are huge amounts of reports of falls for the past centuries. In order to treat these data properly, it is obvious that processing systems should be constructed and developed.

  4. An experimental investigation of the effect of impact generated micro-deformations in Moenkopi and Coconino Sandstone from Meteor Crater, Arizona on subsequent weathering

    Science.gov (United States)

    Verma, A.; Bourke, M. C.; Osinski, G.; Viles, H. A.; Blanco, J. D. R.

    2017-12-01

    Impact cratering is an important geological process that affects all planetary bodies in our solar system. As rock breakdown plays an important role in the evolution of landforms and sediments, it is important to assess the role of inheritance in the subsequent breakdown of impacted rocks.The shock pressure of several gigapascals generated during the impact can exceed the effective strength of target lithology by three to four orders of magnitude and is responsible for melting, vaporisation, shock metamorphism, fracturing and fragmentation of rocks. Environmental conditions and heterogeneities in rock properties exert an important control in rock breakdown. Similar to other subaerial rocks, impacted rocks are affected by a range of rock breakdown processes. In order to better understand the role of inheritance of the impact on rock breakdown, a rock breakdown experiment was conducted in a simulated environmental cabinet under conditions similar to the arid conditions found at the Meteor Crater site. We sampled Moenkopi and Coconino Sandstone from the Meteor Crater impact site in Arizona. For comparison, samples were also collected at control sites close by that have similar rock formations but did not undergo impact. Several established techniques (X-ray CT, SEM, Equotip, SfM) were used to characterise the rock samples before the environmental cabinet experiments. Our laboratory analysis (XRD, SEM, optical microscopy, X-ray CT) on impacted rock samples from Meteor Crater, show that rock porosity and permeability changes due to compaction and fracturing during impact. There were no high-pressure polymorphs of quartz or glass detected in XRD analysis. We ran the experiments on a total of 28 petrophysically characterised 5x5x5 cm sample blocks of Coconino and Moenkopi Sandstone (24 impacted rocks and 4 non-impacted). The results will be presented at the AGU Fall meeting 2017.

  5. Strong Evidence of Variable Micro-meteor Flux from Apollo 17 Samples Obtained at Shorty Crater and on the Light Mantle Avalanche at Taurus-Littrow

    Science.gov (United States)

    Schmitt, H. H.; Petro, N. E.

    2017-12-01

    Light-gray regolith overlying the orange and black pyroclastic ash (Schmitt, 2017) at Shorty Crater protected the ash from incorporation into surrounding basaltic regolith for 3.5 billion years (Tera and Wasserburg, 1976; Saito and Alexander, 1979). Inspection of LROC images indicate this regolith probably came from a 350 m diameter, degraded impact crater (Fitzgibbon Crater), about 1 km NNE of Shorty. This regolith was derived largely from basalt and spread over the ash deposit about 24 Myr (Eugster, et al., 1979, corrected for post-Shorty exposure) after the last ash eruption. Maturity indexes for light gray regolith samples 74441 and 74461 are about 8 (Morris, 1978) and agglutinate concentrations are 8% and 7.7% (Heiken and McKay, 1974), respectively. These values are inconsistent with the exposure and cycling of the light-gray regolith during 3.5 billion years in the lunar surface impact environment (i.e., the time between ash deposition and the light mantle avalanche). If agglutinate content and Is/FeO indexes largely reflect the cumulative effect of micro-meteor impacts, as generally concluded, the light-gray regolith formed in an environment with significantly less micro-meteor flux than that which has prevailed more recently. 14-18% of fragile, ropy glass in the light-gray regolith, as compared with meteor flux during development. The high recent micro-meteor flux appears to have existed for at least for the last 75 million years (Schmitt, et al., 2017), the estimated time using LROC-based crater frequency analysis (van der Bogert, et al., 2012) since the light mantle avalanche of South Massif regolith covered the light-gray regolith. New regolith on the light mantle appears to be developing a higher concentration of agglutinates and a higher maturity index relative to regolith in deeper portions of the unit. Light mantle avalanche samples 73141 (subsurface) and 73121 (near surface), have agglutinates at 32% and 42% and Is/FeO indexes of 48 and 78

  6. Lonely Crater

    Science.gov (United States)

    2005-01-01

    24 December 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a full-resolution (1.5 meters/5 feet per pixel) view of an old meteor impact crater, somewhat filled with sediment. This crater is located near a larger crater, Newcomb, in far northern Noachis Terra. Location near: 22.1oS, 1.1oW Image width: 1 km (0.6 mi) Illumination from: upper left Season: Southern Spring

  7. 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)

  8. Exhumed Craters

    Science.gov (United States)

    2004-01-01

    5 July 2004 Burial and exhumation is a theme that repeats itself, all over the surface of Mars. This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows several north mid-latitude meteor impact craters with bouldery ejecta deposits. Each of the craters was once buried and later exhumed. Mesas on the floors of these craters are remnants of the materials that once filled and covered them. The craters are located near 39.7oN, 206.0oW. The image covers an area about 3 km (1.9 mi) wide; sunlight illuminates the scene from the lower left.

  9. Geochemical and C, O, Sr, and U-series isotopic evidence for the meteoric origin of calcrete at Solitario Wash, Crater Flat, Nevada, USA

    Science.gov (United States)

    Neymark, L. A.; Paces, J. B.; Marshall, B. D.; Peterman, Z. E.; Whelan, J. F.

    2005-08-01

    Calcite-rich soils (calcrete) in alluvium and colluvium at Solitario Wash, Crater Flat, Nevada, USA, contain pedogenic calcite and opaline silica similar to soils present elsewhere in the semi-arid southwestern United States. Nevertheless, a ground-water discharge origin for the Solitario Wash soil deposits was proposed in a series of publications proposing elevation-dependent variations of carbon and oxygen isotopes in calcrete samples. Discharge of ground water in the past would raise the possibility of future flooding in the unsaturated zone at Yucca Mountain, Nevada, site of a proposed high-level nuclear waste repository. New geochemical and carbon, oxygen, strontium, and uranium-series isotopic data disprove the presence of systematic elevation-isotopic composition relations, which are the main justification given for a proposed ground-water discharge origin of the calcrete deposits at Solitario Wash. Values of δ13C (-4.1 to -7.8 per mil [‰]), δ18O (23.8-17.2‰), 87Sr/86Sr (0.71270-0.71146), and initial 234U/238U activity ratios of about 1.6 in the new calcrete samples are within ranges previously observed in pedogenic carbonate deposits at Yucca Mountain and are incompatible with a ground-water origin for the calcrete. Variations in carbon and oxygen isotopes in Solitario Wash calcrete likely are caused by pedogenic deposition from meteoric water under varying Quaternary climatic conditions over hundreds of thousands of years.

  10. Fresh Crater

    Science.gov (United States)

    2004-01-01

    30 July 2004 This full-resolution (1.5 meters, 5 feet, per pixel) Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a fairly small, fresh meteor impact crater in far southeastern Arabia Terra. The crater's bowl, rim, and ejecta exhibit numerous boulders. The image covers an area about 3 km (1.9 mi) wide and is located near 6.9oS, 317.1oW. Sunlight illuminates the terrain from the left.

  11. Filled Craters

    Science.gov (United States)

    2006-01-01

    11 May 2006 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows adjacent impact craters located north-northwest of the Acheron Fossae region of Mars. The two craters are of similar size and formed by meteor impacts. However, one is much more filled than the other, indicating that it is older. The surface of the material in the older, partially-filled crater has a texture similar to the crater's surroundings. The southern (bottom) crater is bowl-shaped and is also partially-filled, however, the filling material seems to be limited to the southern half of the crater. Location near: 44.6oN, 128.4oW Image width: 3 km (1.9 mi) Illumination from: lower left Season: Northern Winter

  12. Secondary Craters

    Science.gov (United States)

    2005-01-01

    7 October 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a cluster of craters in far western Arabia Terra. The crater cluster is oriented along a line that runs nearly east-west (left-right) across the scene. Clusters of craters positioned along a line like this are secondary craters -- that is, they formed as the result of a much larger meteor, asteroid, or cometary impact somewhere else in the region. These craters do not form from the object that impacted Mars to form the larger, primary crater; these are the product of the impact of the rocks and debris thrown out by the larger impact. Location near: 14.9oN, 19.3oW Image width: width: 3 km (1.9 mi) Illumination from: lower left Season: Northern Autumn

  13. Impact Crater

    Science.gov (United States)

    2006-01-01

    16 January 2006 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows an impact crater, roughly the size of the famous Meteor Crater in northern Arizona, U.S.A., in western Elysium Planitia. Light-toned, windblown ripples of sediment have accumulated in subtle troughs and in the lee -- the downwind side -- of the crater. Location near: 28.4oN, 247.9oW Image width: 3 km (1.9 mi) Illumination from: lower left Season: Northern Winter

  14. 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.

  15. Secrets of the Wabar craters

    Science.gov (United States)

    Wynn, Jeffrey C.; Shoemaker, Eugene M.

    1997-01-01

    Focuses on the existence of craters in the Empty Quarter of Saudi Arabia created by the impact of meteors in early times. Mars Pathfinder and Mars Global Surveyor's encounter with impact craters; Elimination of craters in the Earth's surface by the action of natural elements; Impact sites' demand for careful scientific inspections; Location of the impact sites.

  16. Buried Crater

    Science.gov (United States)

    2004-01-01

    29 September 2004 The circular feature in this Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image is the location of a buried impact crater in southern Noachis Terra near 55.4oS, 325.1oW. The image covers an area about 3 km (1.9 mi) across; thus the crater is roughly 2 km in diameter, or twice the size of the famous Meteor Crater in northern Arizona. A visitor to the Arizona Crater would be quite impressed by the height of its raised rims and the depth of and distance across its bowl, relative to a person. At the human scale It is challenging to imagine a crater twice that size that has been filled and buried by sediment and debris, yet the crater shown here is simply an example. On Mars, craters over 100 km in diameter have been buried, and some have been exhumed. This image is illuminated by sunlight from the upper left.

  17. Crater with Streak

    Science.gov (United States)

    2004-01-01

    6 November 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a small meteor impact crater (approximately the size of the famous Meteor Crater in northern Arizona) with a bright wind streak on its west (left) side. Generally, winds blowing from the east (right) have stripped away bright dust everywhere but in the lee of the crater. These landforms are located in eastern Kasei Valles near 25.1oN, 60.8oW. The picture covers an area about 3 km (1.9 mi) wide. Sunlight illuminates the scene from the left/lower left.

  18. 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.

  19. Filled/Eroded Craters

    Science.gov (United States)

    2005-01-01

    14 October 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows rugged terrain in northern Arabia Terra. The circular features are the remains of old meteor impact craters -- either the eroded remnants of the interiors of craters, or the remains of craters that were filled by layered material. The martian bedrock has craters of all sizes and states of erosion interbedded with its layered materials. Location near: 31.4oN, 299.0oW Image width: width: 3 km (1.9 mi) Illumination from: lower left Season: Northern Winter

  20. Degraded Crater

    Science.gov (United States)

    2004-01-01

    21 October 2004 Near the center of this Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image lies the degraded remnants of an old meteor impact crater. The terrain in which it occurs is a heavily eroded, north middle-latitude surface. The image is located in the fretted terrains north of Arabia Terra near 41.3oN, 305.8oW. The image covers an area about 3 km (1.9 mi) wide and sunlight illuminates the scene from the lower left.

  1. Exhuming Craters

    Science.gov (United States)

    2005-01-01

    30 July 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a wind-eroded landscape in the Amazonis Mensa region of far western Tharsis. Two meteor impact craters that formed in -- and then were buried by -- rock are now found in a state of partial-exhumation from within the wind-eroded material. Location near: 2.0oN, 147.3oW Image width: width: 3 km (1.9 mi) Illumination from: lower left Season: Northern Autumn

  2. 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

  3. Formation of Craters in Sand

    Directory of Open Access Journals (Sweden)

    Vanissra Boonyaleepun

    2007-06-01

    Full Text Available The diameter of craters formed by spheres of varying mass dropped into sand at low speed was studied. The relationship between the diameter of the crater formed and the kinetic energy of the projectile at impact was found to be of the same general form as that for planetary meteor craters. The relationship is shown to be a power law with exponent 0.17.

  4. Solis Planum Craters

    Science.gov (United States)

    2005-01-01

    15 January 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows several meteor impact craters on Solis Planum. The second-largest crater in this scene is relatively young and fresh, exhibiting arrayed ejecta pattern and numerous boulders near its raised rim. The image covers an area about 3 km (1.9 mi) wide and is illuminated by sunlight from the upper left. The craters are located near 19.8oS, 85.5oW.

  5. Asymmetric Crater

    Science.gov (United States)

    2004-01-01

    [figure removed for brevity, see original site] Released 18 December 2003Asymmetric craters such as the one in the center of this image are fairly rare. The more typical symmetric craters are formed when meteors impact a surface over a wide range of angles. Only very low impact angles (within 15o of horizontal) result in asymmetric structures such as this one. The bilateral symmetry of the ejecta, like two wings on either side of the elliptical crater, is typical of oblique impacts. The small crater downrange from the main crater could have been caused by the impactor breaking apart before impact or possibly a 'decapitation' of the impactor as it hit with the 'head' traveling farther to form the smaller structure.Image information: VIS instrument. Latitude -8.5, Longitude 227.5 East (132.5 West). 19 meter/pixel resolution.Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  6. Buried Craters of Utopia

    Science.gov (United States)

    2003-01-01

    MGS MOC Release No. MOC2-365, 19 May 2003Beneath the northern plains of Mars are numerous buried meteor impact craters. One of the most heavily-cratered areas, although buried, occurs in Utopia Planitia, as shown in this Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image. The history of Mars is complex; impact craters provide a tool by which to understand some of that history. In this case, a very ancient, cratered surface was thinly-buried by younger material that is not cratered at all. This area is near 48.1oN, 228.2oW; less than 180 km (112 mi) west of the Viking 2 lander site. Sunlight illuminates the scene from the lower left.

  7. Exhuming South Polar Crater

    Science.gov (United States)

    2004-01-01

    7 February 2004 The large, circular feature in this image is an old meteor impact crater. The crater is larger than the 3 kilometers-wide (1.9 miles-wide) Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image, thus only part of the crater is seen. The bright mesas full of pits and holes--in some areas resembling swiss cheese--are composed of frozen carbon dioxide. In this summertime view, the mesa slopes and pit walls are darkened as sunlight causes some of the ice to sublime away. At one time in the past, the crater shown here may have been completely covered with carbon dioxide ice, but, over time, it has been exhumed as the ice sublimes a little bit more each summer. The crater is located near 86.8oS, 111.6oW. Sunlight illuminates this scene from the upper left.

  8. Arabia Crater Cluster

    Science.gov (United States)

    2004-01-01

    27 May 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a portion of a large field of small craters clustered together in northeastern Arabia Terra. Crater clusters usually result from the secondary impact of debris thrown from a much larger impact or from the break-up and impact of fragments of a large meteor. Each crater has subsequently been partially filled by material that erodes to form a rugged crater floor surface, and the general appearance of each crater has been somewhat eroded and modified, as well. The image is located near 34.7oN, 314.7oW, and covers an area about 3 km (1.9 mi) across. Sunlight illuminates the scene from the lower left.

  9. 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.

  10. Small, Bouldery Crater

    Science.gov (United States)

    2004-01-01

    30 April 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a relatively young impact crater located in southeastern Arabia Terra near 4.8oN, 313.9oW. It is about 1 kilometer (about six tenths of a mile) in diameter, roughly the size of the famous Meteor Crater in northern Arizona, U.S.A. Indeed, the Arizona crater may once have looked very similar to this, but erosion on Earth has been more vigorous than on the modern Mars. Large boulders, many of them bigger than a typical house, can be seen in the ejecta blanket and on the crater floor. Fine, bright dust, common throughout Arabia Terra, has thinly mantled all but the steepest slopes. The image is illuminated by sunlight from the left/upper left. The picture covers an area about 3 km (1.9 mi) across.

  11. Craters and Layers

    Science.gov (United States)

    2006-01-01

    11 March 2006 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows some typical relations between impact craters and light-toned, layered rock on Mars. The larger circular feature at the north (top) end of the image marks the location of a filled, buried crater on intermountain terrain north of Hellas Planitia. The larger crater at the southeast (lower right) corner formed by meteor impact into the layered material in which the buried crater is encased. The layered rock, in this case, has a light tone similar to the sedimentary rocks being explored by the Mars Exploration Rover, Opportunity, thousands of kilometers away in Sinus Meridiani. Location near: 24.9oS, 299.3oW Image width: 3 km (1.9 mi) Illumination from: upper left Season: Southern Summer

  12. Northern Plains Buried Craters

    Science.gov (United States)

    2004-01-01

    22 December 2003This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows three circular features on the martian northern plains near 70.7oN, 311.7oW. These circular features are the locations of meteor impact craters that have been buried beneath the plains. Much of the northern plains shares this story, in which thousands of old craters have been filled or partially filled and then thinly buried beneath textured plains. The picture covers an area 3 km (1.9 mi) wide. Sunlight illuminates the scene from the lower left.

  13. Crater Copernicus

    Science.gov (United States)

    1999-01-01

    HUBBLE SHOOTS THE MOON in a change of venue from peering at the distant universe, NASA's Hubble Space Telescope has taken a look at Earth's closest neighbor in space, the Moon. Hubble was aimed at one of the Moon's most dramatic and photogenic targets, the 58 mile-wide (93 km) impact crater Copernicus. The image was taken while the Space Telescope Imaging Spectrograph(STIS) was aimed at a different part of the moon to measure the colors of sunlight reflected off the Moon. Hubble cannot look at the Sun directly and so must use reflected light to make measurements of the Sun's spectrum. Once calibrated by measuring the Sun's spectrum, the STIS can be used to study how the planets both absorb and reflect sunlight.(upper left)The Moon is so close to Earth that Hubble would need to take a mosaic of 130 pictures to cover the entire disk. This ground-based picture from Lick Observatory shows the area covered in Hubble's photomosaic with the WideField Planetary Camera 2..(center)Hubble's crisp bird's-eye view clearly shows the ray pattern of bright dust ejected out of the crater over one billion years ago, when an asteroid larger than a mile across slammed into the Moon. Hubble can resolve features as small as 600 feet across in the terraced walls of the crater, and the hummock-like blanket of material blasted out by the meteor impact.(lower right)A close-up view of Copernicus' terraced walls. Hubble can resolve features as small as 280 feet across.

  14. 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)

  15. Pair of Craters

    Science.gov (United States)

    2005-01-01

    14 July 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a 1.5 meters per pixel (5 ft/pixel) view of a pair of small meteor impact craters in the Arena Colles region of Mars, located north of Isidis Planitia. Location near: 22.7oN, 278.5oW Image width: width: 3 km (1.9 mi) Illumination from: lower left Season: Northern Autumn

  16. Cracked Plain, Buried Craters

    Science.gov (United States)

    2004-01-01

    4 September 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a cracked plain in western Utopia Planitia. The three circular crack patterns indicate the location of three buried meteor impact craters. These landforms are located near 41.9oN, 275.9oW. The image covers an area approximately 3 km (1.9 mi) across. Sunlight illuminates this scene from the lower left.

  17. Wind Streak and Crater

    Science.gov (United States)

    2004-01-01

    23 February 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a wind streak developed in the lee of a meteor impact crater in western Daedalia Planum. The dominant winds responsible for the streak blew from the bottom/lower right (southeast). The image is located near 9.9oS, 144.9oW. Sunlight illuminates the scene from the lower left; the picture covers an area 3 km (1.9 mi) wide.

  18. Crater in Arabia

    Science.gov (United States)

    2004-01-01

    28 October 2004 This high resolution Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a small meteor impact crater with bouldery ejecta in the Arabia Terra region of Mars. The image is located near 11.9oN, 342.2oW. The 300 meter scale bar is about 328 yards long. Sunlight illuminates the scene from the upper left.

  19. Laboratory approach to natural craters, can we?

    International Nuclear Information System (INIS)

    Tara Desai; Dimitri Batani; Marco Bussoli; Annamaria Villa; Biljana Gakovic

    2006-01-01

    Complete test of publication follows. In the present work we report an experimental study on the crater development using Nd:YAG laser system of 40 ps at 1.06 and 0.532 μm laser wavelength with optical energy ∼ 100 and 50 mJ respectively. A flat aluminium (20 x 10 x 2 mm) of density 2.7 g/cc was used as a target. Experiments were performed in a plasma chamber under vacuum exceeding 10 -4 torr. We have measured the diameter and depth of the craters with different techniques. Crater diameter was measured using optical microscope and images were recorded using CCD camera. Optical Confocal Microscope and profilometry were used to measure crater diameter, depth and crater lips. Our preliminary results show that the initial diameter (Φ i ) of the laser spot on the target plays an important role in estimating the final diameter as Φ F = Φ i + E β where E is the incident energy and β ∼ 0.30. under our experimental conditions using 0.532 μm laser. A similar scaling for the meteor-craters yield β = 0.20. - 0.25 for simple craters according to meteor study. Although energy variation is several orders of magnitudes (with few joules laser energy in the lab to megatons of meteor energy), physics of crater formation in both cases draws close resemblance. Aim of our work is to understand the physics of laser produced laboratory craters to recognize some aspects of the natural craters. Recently, Petawatt lasers have been proposed to study meteorite impact physics (Rubenchik LLNL report, 1999). Several megatons meteors approaching the earth with velocity ∼ 20-100 Km/sec is a rare event, approximately, once in million years but accompanying effects persist in time. Remnants of the craters (including simple or complex craters) provide information with substantial margin error about the cratering processes on the terrestrial surfaces (including earth, moon, Jupiter etc.) and, mass and velocity during impact of the dead meteor. Several efforts are being made to scale such

  20. 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

  1. Polygons and Craters

    Science.gov (United States)

    2005-01-01

    3 September 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows polygons enhanced by subliming seasonal frost in the martian south polar region. Polygons similar to these occur in frozen ground at high latitudes on Earth, suggesting that perhaps their presence on Mars is also a sign that there is or once was ice in the shallow subsurface. The circular features are degraded meteor impact craters. Location near: 72.2oS, 310.3oW Image width: width: 3 km (1.9 mi) Illumination from: upper left Season: Southern Spring

  2. Layers in Crater Wall

    Science.gov (United States)

    2004-01-01

    22 January 2004 This January 2004 Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows three distinct bands of layered material exposed in the wall of a south, middle-latitude meteor impact crater wall. Talus--debris shed from erosion of the wall--has piled up on the slopes below the layered outcrop. This picture is located near 45.5oS, 85.9oW, and covers an area 3 km (1.9 mi) wide. Sunlight illuminates the scene from the right/lower right.

  3. 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...

  4. 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

  5. Marte Valles Crater 'Island'

    Science.gov (United States)

    2004-01-01

    10 April 2004 Marte Valles is an outflow channel system that straddles 180oW longitude between the region south of Cerberus and far northwestern Amazonis. The floor of the Marte valleys have enigmatic platy flow features that some argue are formed by lava, others suggest they are remnants of mud flows. This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows an island created in the middle of the main Marte Valles channel as fluid---whether lava or mud---flowed past two older meteor impact craters. The craters are located near 21.5oN, 175.3oW. The image covers an area about 3 km (1.9 mi) across. Sunlight illuminates the scene from the lower left.

  6. Crater in Marte Vallis

    Science.gov (United States)

    2003-01-01

    MGS MOC Release No. MOC2-566, 6 December 2003This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a streamlined tail-pointing toward the upper right (northeast)--in the lee of a meteor impact crater in Marte Vallis, a large valley and channel complex southeast and east of the Elysium volcanic region. The fluid that went through Marte Vallis, whether water, mud, lava, or otherwise, created this form as it moved from the lower left (southwest) toward the upper right. The crater is located near 19.0oN, 174.9oW. The image covers an area 3 km (1.9 mi) wide and is illuminated from the left.

  7. Northern Plains 'Crater'

    Science.gov (United States)

    2004-01-01

    10 December 2004 The lower left (southwest) corner of this Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows the location of a somewhat filled and buried meteor impact crater on the northern plains of Mars. The dark dots are boulders. A portion of a similar feature is seen in the upper right (northeast) corner of the image. This picture, showing landforms (including the odd mound north/northeast of the crater) that are typical of the martian northern lowland plains, was obtained as part of the MGS MOC effort to support the search for a landing site for the Phoenix Mars Scout lander. Phoenix will launch in 2007 and land on the northern plains in 2008. This image is located near 68.0oN, 227.4oW, and covers an area approximately 3 km (1.9 mi) wide. The scene is illuminated by sunlight from the lower left.

  8. Iturralde Crater, Bolivia

    Science.gov (United States)

    2002-01-01

    NASA scientists will venture into an isolated part of the Bolivian Amazon to try and uncover the origin of a 5 mile (8 kilometer) diameter crater there known as the Iturralde Crater. Traveling to this inhospitable forest setting, the Iturralde Crater Expedition 2002 will seek to determine if the unusual circular crater was created by a meteor or comet. Organized by Dr. Peter Wasilewski of NASA's Goddard Space Flight Center, Greenbelt, Md., the Iturralde Crater Expedition 2002 will be led by Dr. Tim Killeen of Conservation International, which is based in Bolivia. Killeen will be assisted by Dr. Compton Tucker of Goddard. The team intends to collect and analyze rocks and soil, look for glass particles that develop from meteor impacts and study magnetic properties in the area to determine if the Iturralde site was indeed created by a meteor.This image was acquired on June 29, 2001 by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite. With its 14 spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER will image Earth for the next 6 years to map and monitor the changing surface of our planet.ASTER is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of Economy, Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products.The broad spectral coverage and high spectral resolution of ASTER will provide scientists in numerous disciplines with critical information for surface mapping, and monitoring dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats; monitoring potentially active volcanoes; identifying crop stress; determining cloud morphology and physical properties; wetlands evaluation; thermal pollution

  9. Gullies in Crater in Hellas

    Science.gov (United States)

    2003-01-01

    MGS MOC Release No. MOC2-571, 11 December 2003This October 2003 Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows gullies cut into debris on the southeast-facing wall of an old meteor impact crater in southeastern Hellas Planitia. This view is located near 44.5oS, 277.0oW. The 200 meter scale bar is approximately 656 feet across; the picture is illuminated from the upper left.

  10. 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.

  11. 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.

  12. 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

  13. 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)

  14. 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

  15. Impact Crater in Coastal Patagonia

    Science.gov (United States)

    D'Antoni, Hector L; Lasta, Carlos A.; Condon, Estelle (Technical Monitor)

    2000-01-01

    Impact craters are geological structures attributed to the impact of a meteoroid on the Earth's (or other planet's) surface (Koeberl and Sharpton. 1999). The inner planets of the solar system as well as other bodies such as our moon show extensive meteoroid impacts (Gallant 1964, French 1998). Because of its size and gravity, we may assume that the Earth has been heavily bombarded but weathering and erosion have erased or masked most of these features. In the 1920's, a meteor crater (Mark 1987) was identified in Arizona and to this first finding the identification of a large number of impact structures on Earth followed (Hodge 1994). Shock metamorphic effects are associated with meteorite impact craters. Due to extremely high pressures, shatter cones are produced as well as planar features in quartz and feldspar grains, diaplectic glass and high-pressure mineral phases such as stishovite (French 1998).

  16. 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)

  17. 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.

  18. 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

  19. A Tale of 3 Craters

    Science.gov (United States)

    2004-01-01

    11 November 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image captures some of the complexity of the martian upper crust. Mars does not simply have an impact-cratered surface, it's upper crust is a cratered volume. Over time, older craters on Mars have been eroded, filled, buried, and in some cases exhumed and re-exposed at the martian surface. The crust of Mars is layered to depths of 10 or more kilometers, and mixed in with the layered bedrock are a variety of ancient craters with diameters ranging from a few tens of meters (a few tens of yards) to several hundred kilometers (more than one or two hundred miles). The picture shown here captures some of the essence of the layered, cratered volume of the upper crust of Mars in a very simple form. The image shows three distinct circular features. The smallest, in the lower right quarter of the image, is a meteor crater surrounded by a mound of material. This small crater formed within a layer of bedrock that once covered the entire scene, but today is found only in this small remnant adjacent to the crater. The intermediate-sized crater, west (left) of the small one, formed either in the next layer down--that is, below the layer in which the small crater formed--or it formed in some layers that are now removed, but was big enough to penetrate deeply into the rock that is near the surface today. The largest circular feature in the image, in the upper right quarter of the image, is still largely buried. It formed in layers of rock that are below the present surface. Erosion has brought traces of its rim back to the surface of Mars. This picture is located near 50.0oS, 77.8oW, and covers an area approximately 3 km (1.9 mi) across. Sunlight illuminates this October 2004 image from the upper left.

  20. Proceedings of the Geophysical Laboratory/Lawrence Radiation Laboratory Cratering Symposium

    Energy Technology Data Exchange (ETDEWEB)

    Nordyke, Milo D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    1961-10-01

    The geological papers in this morning's session will deal descriptively with surficial features and end products of impact craters caused by meteorite falls. Such items as breccia, structural deformation, normal and inverse stratigraphy, glass (fused rock), and coesite will frequently be mentioned. Meteor and explosion crater data are presented.

  1. 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)

  2. 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.

  3. 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.)

  4. 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.

  5. 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).

  6. 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.

  7. Impact cratering

    Indian Academy of Sciences (India)

    In addition, further improvement of our understanding of the physico–chemical and geological processes fundamental to the impact cratering process is required for reliable numerical modeling of the process, and also for the correlation of impact magnitude and environmental effects. Over the last few decades, impact ...

  8. 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

  9. 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.

  10. BARRINGER AWARD ADDRESS: Shock Metamorphism of Quartz in Nature and Experiment: A Review

    Science.gov (United States)

    Stoffler, D.

    1993-07-01

    Quartz as a widespread rock-forming mineral of the Earth's crust represents the most sensitive indicator of impact-induced shock waves and therefore provides an outstanding tool for the recognition of terrestrial impact formations and for the pressure calibration of shock metamorphosed rocks. This paper attempts to summarize the current knowledge in this field. Shocked quartz has been observed in quite variable spatial relations to impact craters: (1) in the crater basement, (2) in rock and mineral clasts of polymict breccias, and (3) in distal ejecta such as tektites and global air- fall beds (e.g., K/T boundary). Quartz displays a wide variety of shock- induced mechanical deformations and transformations [1,2]. Microscopically observable effects are multiple sets of planar fractures (PF) and planar deformation features (PDF) parallel to low indices crystallographic planes; mosaickism; reduced refractivity and birefringence; partial transformation to stishovite; increased optic axial angle; amorphization (diaplectic glass), partial transformation to coesite; and melting (lechatelierite). Additional effects at the atomic scale are well documented by TEM, X-ray diffraction and spectroscopy [3-7]. All types of shock effects observed so far in natural quartz have been reproduced by experimental shock waves in the laboratory and in large scale TNT and nuclear explosions. By means of sophisticated techniques the pressure dependence of shock effects has been calibrated with high precision. Threshold pressures at room temperature (given in GPa) for the onset of certain effects in single crystals and in nonporous quartzofeldpathic rocks are: 7.5 +- 2, 10 +- 2, 20 +- 2 (various PFs and PDFs), 12 +- 1 (stishovite), 25 +- 1 (reduced refractive index and density), ~30 (coesite), 34 +- 1 (total transformation to diaplectic glass), 50 +- 2 (melting and formation of lechatelierite) [8-12]. The type of shock effects, their paragenetic combination, and their formation pressure are

  11. Galle Crater

    Science.gov (United States)

    2002-01-01

    (Released 19 June 2002) The Science This image is of part of Galle Crater, located at 51.9S, 29.5W. This image was taken far enough south and late enough into the southern hemisphere fall to catch observe water ice clouds partially obscuring the surface. The most striking aspect of the surface is the dissected layered unit to the left in the image. Other areas also appear to have layering, but they are either more obscured by clouds or are less well defined on the surface. The layers appear to be mostly flat lying and layer boundaries appear as topographic lines would on a map, but there are a few areas where it appears that these layers have been deformed to some level. Other areas of the image contain rugged, mountainous terrain as well as a separate pitted terrain where the surface appears to be a separate unit from the mountains and the layered terrain. The Story Galle Crater is officially named after a German astronomer who, in 1846, was the first to observe the planet Neptune. It is better known, however, as the 'Happy Face Crater.' The image above focuses on too small an area of the crater to see its beguiling grin, but you can catch the rocky line of a 'half-smile' in the context image to the right (to the left of the red box). While water ice clouds make some of the surface harder to see, nothing detracts from the fabulous layering at the center left-hand edge of the image. If you click on the above image, the scalloped layers almost look as if a giant knife has swirled through a landscape of cake frosting. These layers, the rugged, mountains near them, and pits on the surface (upper to middle section of the image on the right-hand side) all create varying textures on the crater floor. With such different features in the same place, geologists have a lot to study to figure out what has happened in the crater since it formed.

  12. Centrifuge impact cratering experiment 5

    Science.gov (United States)

    1984-01-01

    Transient crates motions, cratering flow fields, crates dynamics, determining impact conditions from total crater welt, centrifuge quarter-space cratering, and impact cratering mechanics research is documented.

  13. 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.

  14. 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.

  15. 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.

  16. 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)

  17. Cutting Craters

    Science.gov (United States)

    2003-01-01

    [figure removed for brevity, see original site] Released 12 November 2003The rims of two old and degraded impact craters are intersected by a graben in this THEMIS image taken near Mangala Fossa. Yardangs and low-albedo wind streaks are observed at the top of the image as well as interesting small grooves on the crater floor. The origin of these enigmatic grooves may be the result of mud or lava and volatile interactions. Variable surface textures observed in the bottom crater floor are the result of different aged lava flows.Image information: VIS instrument. Latitude -15.2, Longitude 219.2 East (140.8 West). 19 meter/pixel resolution.Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time. NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  18. 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 ...

  19. Buried Mid-Latitude Craters

    Science.gov (United States)

    2004-01-01

    MGS MOC Release No. MOC2-577, 17 December 2003This September 2003 Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) picture shows six circular features, three of which exhibit concentric, or 'bullseye,' patterns within them. Each circular feature is the remains of a partly-buried, partly-eroded, and partly-filled meteor impact crater. These occur in northeastern Arabia Terra. Areas such as this, located near the middle latitudes of Mars, commonly have a 'scabby' or roughened appearance. The cause of this 'terrain roughening' texture is unknown, although some scientists have speculated that it might result from the erosion and removal (by way of sublimation) of ground ice. This idea remains highly speculative. These features are located near 28.4oN, 317.5oW. The image covers an area 3 km (1.9 mi) wide; sunlight illuminates the scene from the lower left.

  20. Layers and Boulders in Crater Wall, Nepenthes Mensae Region

    Science.gov (United States)

    1999-01-01

    Peering down into craters offers Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) scientists an opportunity to examine one of the few landforms that Mars shares in common with the other planets and moons of our Solar System.The picture on the left (above) is a MOC context frame taken at the same time as the MOC high resolution image on the right. The white box on the left shows the location of the high resolution view. The high resolution image was targeted on a 3 kilometers (1.9 miles) wide impact crater on the floor of a larger crater in the Nepenthes Mensae region (near 3oS, 239oW). The context image is about 115 km (71 mi) across, the high-resolution image is 3 km (1.9 mi) across, and both are illuminated from the left/lower left.The 3 km diameter crater in the MOC image on the right is three times wider than the famous Meteor Crater in northern Arizona, USA. The high resolution image shows many small windblown drifts or dunes in the low areas both within the crater and outside on the surrounding terrain. Some portions of the crater's walls exhibit outcrops of bare, layered rock. Large boulders have been dislodged from the walls and have tumbled down the slopes to the crater floor. Many of these boulders are bigger than school buses and automobiles.

  1. A Bright Lunar Impact Flash Linked to the Virginid Meteor Complex

    Science.gov (United States)

    Moser, D. E.; Suggs, R. M.; Suggs, R. J.

    2015-01-01

    Since early 2006, NASA's Marshall Space Flight Center (MSFC) has observed over 330 impact flashes on the Moon, produced by meteoroids striking the lunar surface. On 17 March 2013 at 03:50:54.312 UTC, the brightest flash of a 9-year routine observing campaign was observed by two 0.35 m telescopes at MSFC. The camera onboard the Lunar Reconnaissance Orbiter (LRO), a NASA spacecraft mapping the Moon from lunar orbit, discovered the fresh crater associated with this impact [1] approximately 3 km from the location predicted by a newly developed geolocation technique [2]. The meteoroid impactor responsible for this event may have been part of a stream of large particles encountered by the Earth/Moon associated with the Virginid Meteor Complex, as evidenced by a cluster of five fireballs seen in Earth's atmosphere on the same night by the NASA All Sky Fireball Network [3] and the Southern Ontario Meteor Network [4]. Crater size calculations based on assumptions derived from fireball measurements yielded an estimated crater diameter of 10-23 m rim-to-rim using the Holsapple [5] and Gault [6] models, a result consistent with the observed crater measured to be 18 m across. This is the first time a lunar impact flash has been associated with fireballs in Earth's atmosphere and an observed crater.

  2. 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.

  3. 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

  4. 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.

  5. 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

  6. Determination of elemental abundances in impact materials by micro-PIXE and micro-SRXRF methods

    International Nuclear Information System (INIS)

    Uzonyi, I.; Szabo, Gy.; Kiss, A.Z.; Szoeoer, Gy.; Rozsa, P.

    2004-01-01

    The most famous and well-preserved meteorite crater in the world is the Barringer Meteor Crater (Arizona, USA). The meteorite is supposed to be a fragment of a small asteroid of our solar system. During the impact event the matter of the projectile mixed with that of the target rocks forming breccias, slag and spherules. For the non-destructive characterization of the impact materials a combined micro-PIXE and micro-SRXRF technique was applied. (N.T.)

  7. 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.

  8. 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.

  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. Dome craters on Ganymede

    International Nuclear Information System (INIS)

    Moore, J.M.; Malin, M.C.

    1987-01-01

    Voyager observations reveal impact craters on Ganymede that are characterized by the presence of broad, high albedo, topographic domes situated within a central pit. Fifty-seven craters with central domes were identified in images covering approx. 50% of the surface. Owing to limitations in resolution, and viewing and illumination angles, the features identified are most likely a subset of dome craters. The sample appears to be sufficiently large to infer statistically meaningful trends. Dome craters appear to fall into two distinct populations on plots of the ratio of dome diameter to crater rim diameter, large-dome craters and small-dome craters. The two classes are morphologically distinct from one another. In general, large dome craters show little relief and their constituent landforms appear subdued with respect to fresh craters. The physical attributes of small-dome craters are more sharply defined, a characteristic they share with young impact craters of comparable size observed elsewhere in the solar system. Both types of dome craters exhibit central pits in which the dome is located. As it is difficult to produce domes by impact and/or erosional processes, an endogenic origin for the domes is reasonably inferred. Several hypotheses for their origin are proposed. These hypotheses are briefly reviewed

  11. 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.

  12. Impact craters on Titan

    Science.gov (United States)

    Wood, Charles A.; Lorenz, Ralph; Kirk, Randy; Lopes, Rosaly; Mitchell, Karl; Stofan, Ellen; ,

    2010-01-01

    Five certain impact craters and 44 additional nearly certain and probable ones have been identified on the 22% of Titan's surface imaged by Cassini's high-resolution radar through December 2007. The certain craters have morphologies similar to impact craters on rocky planets, as well as two with radar bright, jagged rims. The less certain craters often appear to be eroded versions of the certain ones. Titan's craters are modified by a variety of processes including fluvial erosion, mass wasting, burial by dunes and submergence in seas, but there is no compelling evidence of isostatic adjustments as on other icy moons, nor draping by thick atmospheric deposits. The paucity of craters implies that Titan's surface is quite young, but the modeled age depends on which published crater production rate is assumed. Using the model of Artemieva and Lunine (2005) suggests that craters with diameters smaller than about 35 km are younger than 200 million years old, and larger craters are older. Craters are not distributed uniformly; Xanadu has a crater density 2-9 times greater than the rest of Titan, and the density on equatorial dune areas is much lower than average. There is a small excess of craters on the leading hemisphere, and craters are deficient in the north polar region compared to the rest of the world. The youthful age of Titan overall, and the various erosional states of its likely impact craters, demonstrate that dynamic processes have destroyed most of the early history of the moon, and that multiple processes continue to strongly modify its surface. The existence of 24 possible impact craters with diameters less than 20 km appears consistent with the Ivanov, Basilevsky and Neukum (1997) model of the effectiveness of Titan's atmosphere in destroying most but not all small projectiles.

  13. Degraded Crater Rim

    Science.gov (United States)

    2002-01-01

    (Released 3 May 2002) The Science The eastern rim of this unnamed crater in Southern Arabia Terra is very degraded (beaten up). This indicates that this crater is very ancient and has been subjected to erosion and subsequent bombardment from other impactors such as asteroids and comets. One of these later (younger) craters is seen in the upper right of this image superimposed upon the older crater rim material. Note that this smaller younger crater rim is sharper and more intact than the older crater rim. This region is also mantled with a blanket of dust. This dust mantle causes the underlying topography to take on a more subdued appearance. The Story When you think of Arabia, you probably think of hot deserts and a lot of profitable oil reserves. On Mars, however, Southern Arabia Terra is a cold place of cratered terrain. This almost frothy-looking image is the badly battered edge of an ancient crater, which has suffered both erosion and bombardment from asteroids, comets, or other impacting bodies over the long course of its existence. A blanket of dust has also settled over the region, which gives the otherwise rugged landscape a soft and more subdued appearance. The small, round crater (upper left) seems almost gemlike in its setting against the larger crater ring. But this companionship is no easy romance. Whatever formed the small crater clearly whammed into the larger crater rim at some point, obliterating part of its edge. You can tell the small crater was formed after the first and more devastating impact, because it is laid over the other larger crater. How much younger is the small one? Well, its rim is also much sharper and more intact, which gives a sense that it is probably far more youthful than the very degraded, ancient crater.

  14. Postulated impact craters yield oil and gas, lively debate

    Energy Technology Data Exchange (ETDEWEB)

    Petzet, G.A.

    1995-04-10

    Impact craters, also called astroblemes, are the most common landform in the solar system, and several on earth have produced oil and gas. Significant cross-disciplinary study is being aimed at understanding the origin, structure, and economic potential of surface and buried craters worldwide. The Oklahoma Geological Survey and the US Department of Energy organized a workshop to discuss the Ames structure, a feature in Major Country, Okla., along the sprawling, giant Sooner Trend/Ringwood oil producing complex. This rundown is designed to provide basic information gleaned from speakers and abstracts presented at the workshop. OGS is to publish proceedings later. This paper discusses meteors vs. volcanoes, the Oklahoma crater, questions about Ames, producing astroblemes, and future research.

  15. Large Crater Clustering tool

    Science.gov (United States)

    Laura, Jason; Skinner, James A.; Hunter, Marc A.

    2017-08-01

    In this paper we present the Large Crater Clustering (LCC) tool set, an ArcGIS plugin that supports the quantitative approximation of a primary impact location from user-identified locations of possible secondary impact craters or the long-axes of clustered secondary craters. The identification of primary impact craters directly supports planetary geologic mapping and topical science studies where the chronostratigraphic age of some geologic units may be known, but more distant features have questionable geologic ages. Previous works (e.g., McEwen et al., 2005; Dundas and McEwen, 2007) have shown that the source of secondary impact craters can be estimated from secondary impact craters. This work adapts those methods into a statistically robust tool set. We describe the four individual tools within the LCC tool set to support: (1) processing individually digitized point observations (craters), (2) estimating the directional distribution of a clustered set of craters, back projecting the potential flight paths (crater clusters or linearly approximated catenae or lineaments), (3) intersecting projected paths, and (4) intersecting back-projected trajectories to approximate the local of potential source primary craters. We present two case studies using secondary impact features mapped in two regions of Mars. We demonstrate that the tool is able to quantitatively identify primary impacts and supports the improved qualitative interpretation of potential secondary crater flight trajectories.

  16. 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.)

  17. 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.

  18. 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

  19. 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.

  20. 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

  1. Impact and cratering rates onto Pluto

    Science.gov (United States)

    Greenstreet, Sarah; Gladman, Brett; McKinnon, William B.

    2015-09-01

    The New Horizons spacecraft fly-through of the Pluto system in July 2015 will provide humanity's first data for the crater populations on Pluto and its binary companion, Charon. In principle, these surfaces could be dated in an absolute sense, using the observed surface crater density (# craters/km2 larger than some threshold crater diameter D). Success, however, requires an understanding of both the cratering physics and absolute impactor flux. The Canada-France Ecliptic Plane Survey (CFEPS) L7 synthetic model of classical and resonant Kuiper belt populations (Petit, J.M. et al. [2011]. Astron. J. 142, 131-155; Gladman, B. et al. [2012]. Astron. J. 144, 23-47) and the scattering object model of Kaib et al. (Kaib, N., Roškar, R., Quinn, T. [2011]. Icarus 215, 491-507) calibrated by Shankman et al. (Shankman, C. et al. [2013]. Astrophys. J. 764, L2-L5) provide such impact fluxes and thus current primary cratering rates for each dynamical sub-population. We find that four sub-populations (the q impact flux, each providing ≈ 15- 25 % of the total rate. Due to the uncertainty in how the well-characterized size distribution for Kuiper belt objects (with impactor diameter d > 100km) connects to smaller projectiles, we compute cratering rates using five model impactor size distributions: a single power-law, a power-law with a knee, a power-law with a divot, as well as the "wavy" size distributions described in Minton et al. (Minton, D.A. et al. [2012]. Asteroids Comets Meteors Conf. 1667, 6348) and Schlichting et al. (Schlichting, H.E., Fuentes, C.I., Trilling, D.E. [2013]. Astron. J. 146, 36-42). We find that there is only a small chance that Pluto has been hit in the past 4 Gyr by even one impactor with a diameter larger than the known break in the projectile size distribution (d ≈ 100km) which would create a basin on Pluto (D ⩾ 400km in diameter). We show that due to present uncertainties in the impactor size distribution between d = 1- 100km , computing

  2. Effects of Pre-Existing Target Structure on the Formation of Large Craters

    Science.gov (United States)

    Barnouin-Jha, O. S.; Cintala, M. J.; Crawford, D. A.

    2003-01-01

    The shapes of large-scale craters and the mechanics responsible for melt generation are influenced by broad and small-scale structures present in a target prior to impact. For example, well-developed systems of fractures often create craters that appear square in outline, good examples being Meteor Crater, AZ and the square craters of 433 Eros. Pre-broken target material also affects melt generation. Kieffer has shown how the shock wave generated in Coconino sandstone at Meteor crater created reverberations which, in combination with the natural target heterogeneity present, created peaks and troughs in pressure and compressed density as individual grains collided to produce a range of shock mineralogies and melts within neighboring samples. In this study, we further explore how pre-existing target structure influences various aspects of the cratering process. We combine experimental and numerical techniques to explore the connection between the scales of the impact generated shock wave and the pre-existing target structure. We focus on the propagation of shock waves in coarse, granular media, emphasizing its consequences on excavation, crater growth, ejecta production, cratering efficiency, melt generation, and crater shape. As a baseline, we present a first series of results for idealized targets where the particles are all identical in size and possess the same shock impedance. We will also present a few results, whereby we increase the complexities of the target properties by varying the grain size, strength, impedance and frictional properties. In addition, we investigate the origin and implications of reverberations that are created by the presence of physical and chemical heterogeneity in a target.

  3. 10Be content in clasts from fallout suevitic breccia in drill cores from the Bosumtwi impact crater, Ghana: Clues to preimpact target distribution

    Science.gov (United States)

    Losiak, Anna; Wild, Eva Maria; Michlmayr, Leonard; Koeberl, Christian

    2014-03-01

    Rocks from drill cores LB-07A (crater fill) and LB-08A (central uplift) into the Bosumtwi impact crater, Ghana, were analyzed for the presence of the cosmogenic radionuclide 10Be. The aim of the study was to determine the extent to which target rocks of various depths were mixed during the formation of the crater-filling breccia, and also to detect meteoric water infiltration within the impactite layer. 10Be abundances above background were found in two (out of 24) samples from the LB-07A core, and in none of five samples from the LB-08A core. After excluding other possible explanations for an elevated 10Be signal, we conclude that it is most probably due to a preimpact origin of those clasts from target rocks close to the surface. Our results suggest that in-crater breccias were well mixed during the impact cratering process. In addition, the lack of a 10Be signal within the rocks located very close to the lake sediment-impactite boundary suggests that infiltration of meteoric water below the postimpact crater floor was limited. This may suggest that the infiltration of the meteoric water within the crater takes place not through the aerial pore-space, but rather through a localized system of fractures.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. Cratering on Small Bodies: Lessons from Eros

    Science.gov (United States)

    Chapman, C. R.

    2003-01-01

    Cratering and regolith processes on small bodies happen continuously as interplanetary debris rains down on asteroids, comets, and planetary satellites. Butthey are very poorly observed and not well understood. On the one hand, we have laboratory experimentation at small scales and we have examination of large impact craters (e.g. Meteor Crater on Earth and imaging of abundant craters on terrestrial planets and outer planet moons). Understanding cratering on bodies of intermediate scales, tens of meters to hundreds of km in size, involves either extrapolation from our understanding of cratering phenomena at very different scales or reliance on very preliminary, incomplete examination of the observational data we now have for a few small bodies. I review the latter information here. It has been generally understood that the role of gravity is greatly diminished for smaller bodies, so a lot of cratering phenomena studied for larger bodies is less applicable. But it would be a mistake to imagine that laboratory experiments on gravitationless rocks (usually at 1 g) are directly applicable, except perhaps to those monolithic Near Earth Asteroids (NEAs) some tens of meters in size that spin very rapidly and can be assumed to be "large bare rocks" with "negative gravity". Whereas it had once been assumed that asteroids smaller than some tens of km diameter would retain little regolith, it is increasingly apparent that regolith and megoregolith processes extend down to bodies only hundreds of meters in size, perhaps smaller. Yet these processes are very different from those that pertain to the Moon, which is our chief prototype of regolith processes. The NEAR Shoemaker spacecraft's studies of Eros provide the best evidence to date about small-body cratering processes, as well as a warning that our theoretical understanding requires anchoring by direct observations. Eros: "Ponds", Paucity of Small Craters, and Other Mysteries. Although Eros is currently largely detached

  9. Venus - Crater Aurelia

    Science.gov (United States)

    1990-01-01

    This Magellan image shows a complex crater, 31.9 kilometers (20 miles) in diameter with a circular rim, terraced walls, and central peaks, located at 20.3 degrees north latitude and 331.8 degrees east longitude. Several unusual features are evidenced in this image: large dark surface up range from the crater; lobate flows emanating from crater ejecta, and very radar-bright ejecta and floor. Aurelia has been proposed to the International Astronomical Union, Subcommittee of Planetary Nomenclature as a candidate name. Aurelia is the mother of Julius Caesar.

  10. Crater in Utopia

    Science.gov (United States)

    2004-01-01

    23 March 2004 Craters of the martian northern plains tend to be somewhat shallow because material has filled them in. Their ejecta blankets, too, are often covered by younger materials. This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows an example--a crater in Utopia Planitia near 43.7oN, 227.3oW. Erosion has roughened some of the surfaces of the material that filled the crater and covered its ejecta deposit. The picture covers an area about 3 km (1.9 mi) across. Sunlight illuminates the scene from the lower left.

  11. 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.

  12. 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).

  13. 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

  14. 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

  15. 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.)

  16. 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)

  17. Ganymede Crater Database

    Data.gov (United States)

    National Aeronautics and Space Administration — This web page leads to a database of images and information about the 150 major impact craters on Ganymede and is updated semi-regularly based on continuing analysis...

  18. Venus Crater Database

    Data.gov (United States)

    National Aeronautics and Space Administration — This web page leads to a database of images and information about the 900 or so impact craters on the surface of Venus by diameter, latitude, and name.

  19. Callisto Crater Database

    Data.gov (United States)

    National Aeronautics and Space Administration — This web page leads to a database of images and information about the 150 major impact craters on Callisto and is updated semi-regularly based on continuing analysis...

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

    Science.gov (United States)

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

    2015-01-01

    Meteoroids are natural particles with origins from comets, asteroids, and planets from within the solar system. On average, 33 metric tons (73,000 lb) of meteoroids hit Earth everyday with velocities ranging between 20 and 72 km/s. However, the vast majority of these meteoroids disintegrate in the atmosphere and never make it to the ground. The Moon also encounters the same meteoroid flux, but has no atmosphere to stop them from striking the surface. At such speeds even a small meteoroid has incredible energy. A meteoroid with a mass of only 5 kg can excavate a crater over 9 m across, hurling 75 metric tons (165,000 lb) of lunar soil and rock on ballistic trajectories above the lunar surface. Meteoroids with particle sizes as small as 100 micrometer (1 Microgram) can do considerable damage to spacecraft in Earth's orbit and beyond. Impacts can damage thermal protection systems, radiators, windows, and pressurized containers. Secondary effects might include partial penetration or pitting, local deformation, and surface degradation that can cause a failure upon reentry. The speed, mass, density, and flux of meteoroids are important factors for design considerations and mitigation during operations. Lunar operations (unmanned and manned) are also adversely affected by the meteoroid flux. Ejecta from meteoroid impacts is also part of the lunar environment and must be characterized. Understanding meteoroid fluxes and the associated risk of meteoroids impacting spacecraft traveling in and beyond Earth's orbit is the objective of the Meteoroid Environment Office (MEO) located at Marshall Space Flight Center (MSFC). One of the MEO's programs is meteoroid impact monitoring of the Moon. The large collecting area of the night side of the lunar disk provides statistically significant counts of meteoroids that can provide useful information about the flux of meteoroids in the hundreds of grams to kilograms size range. This information is not only important for characterizing

  1. Multivariate analyses of crater parameters and the classification of craters

    Science.gov (United States)

    Siegal, B. S.; Griffiths, J. C.

    1974-01-01

    Multivariate analyses were performed on certain linear dimensions of six genetic types of craters. A total of 320 craters, consisting of laboratory fluidization craters, craters formed by chemical and nuclear explosives, terrestrial maars and other volcanic craters, and terrestrial meteorite impact craters, authenticated and probable, were analyzed in the first data set in terms of their mean rim crest diameter, mean interior relief, rim height, and mean exterior rim width. The second data set contained an additional 91 terrestrial craters of which 19 were of experimental percussive impact and 28 of volcanic collapse origin, and which was analyzed in terms of mean rim crest diameter, mean interior relief, and rim height. Principal component analyses were performed on the six genetic types of craters. Ninety per cent of the variation in the variables can be accounted for by two components. Ninety-nine per cent of the variation in the craters formed by chemical and nuclear explosives is explained by the first component alone.

  2. 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.

  3. The Stickney Crater ejecta secondary impact crater spike on Phobos: Implications for the age of Stickney and the surface of Phobos

    Science.gov (United States)

    Ramsley, Kenneth R.; Head, James W.

    2017-04-01

    Phobos that reoriented Phobos to its present-day synchronous ;tidal lock; longitude, 4) set limits on the volume of low-velocity Stickney ejecta that is available to produce Phobos grooves from rolling boulders, and 5) estimate the crater SFD of a meteor spike on Mars from a trailing hemisphere Stickney impact.

  4. 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...

  5. 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.

  6. 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

  7. 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...

  8. 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.

  9. 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)

  10. 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

  11. 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...

  12. 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

  13. 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)

  14. 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.

  15. 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.

  16. 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

  17. High mobility of landslides on the lunar crater rims

    Science.gov (United States)

    Fukuoka, H.; Akao, H.; Miyauchi, D.; Okamoto, A.; Kawase, T.; Ichimura, M.; Chifu, D.; Inui, K.

    2011-12-01

    The Kaguya (Selene) lunar orbiter which was launched by JAXA in 2007 brought about a lot of topographical data using laser altimeter (LALT), terrain (wide-view) camera, and HD TV camera. This mission revised the lunar atlas with highest resolution of 10 m. The number of LALT surveyed points is about 6.7 million. Their evaluated precision is about 4 m, and the positioning precision is about 80 m (1 STD, respectively). Most of the obtained topographic data are implemented in Google Moon, which are available in the public for free of charge. JAXA revealed that there are numerous landslide topography especially along the lunar crater rims. In order to compare the mobility of those in Mars, we have examined the apparent friction (H/T) in major craters. Apparently, those landslides are distributed on rather older and dissected crater rims. It means their occurrence must be much later than the crater formation. In most cases, the H/T values of those landslides are around 0.1, like long-runout landslides on the Mars and Earth. Past studies proved that ground water might have taken most important role in the presence of such low H/L landslide events on the earth and Mars. However, there have been no evidence nor implication reported, of past water existence on the moon. Possible mechanisms of these low H/T on the crater are (1) moon quake due to nearby meteor impact; (2) shear resistance reduction due to long-term physical/chemical weathering and existence of little ground water; (3) exotic mechanism including tectonic function.

  18. 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.

  19. 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.

  20. 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.

  1. 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

  2. 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.

  3. 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

  4. 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.

  5. 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...

  6. 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.

  7. 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.

  8. Underwater research methods for study of nuclear bomb craters, Enewetak, Marshall Islands

    Science.gov (United States)

    Shinn, E.A.; Halley, R.B.; Kindinger, J.L.; Hudson, J.H.; Slate, R.A.

    1990-01-01

    Three craters, created by the explosion of nuclear fusion devices, were mapped, sampled, core drilled and excavated with airlifts at Enewetak Atoll in the Marshall Islands by using scuba and a research submersible. The craters studied were Mike, Oak, and Koa. Tests took place near sea level at the transition between lithified reef flat and unlithified lagoonal sediments, where water depth ranged from 1 to 4 m. Craters produced by the blasts ranged from 30 to 60 m in depth. The purpose of our study was to determine crater diameter and depth immediately after detonation. Observations of submerged roadways and testing structures and upturned crater rims similar to those characteristic of meteor impacts indicate that the initial, or transient, craters were smaller than their present size. At some later time, while the area was too radioactive for direct examination, the sides of the craters slumped owing to dewatering of under lying pulverized rock. Core drilling of crater margins with a diver-operated hydraulic coring device provided additional data. On the seaward margin of the atoll, opposite Mike, a large portion of the atoll rim approximately the size of a city block had slumped into the deep ocean, leaving a clean vertical rock section more than 400m high. An abundance of aggressive grey reef sharks displaying classic territorial behavior prevented use of scuba at the Mike slump site. The two-person submersible R.V. Delta provided protection and allowed observations down to 300 m. During the 6-week period of study, we made more than 300 scuba and 275 submersible dives. Mapping was with side scan sonar and continuous video sweeps supplemented by tape-recorded verbal descriptions made from within the submersible. A mini-ranger navigation system linked to the submersible allowed plotting of bottom features, depth and sediment type with spatial accuracy to within 2 m.

  9. Meteoroids and impact craters

    Science.gov (United States)

    Spall, H.

    1986-01-01

    On a clear night scores of meteoroids streak across the sky. they leave light paths we call meteors or shooting stars as the Earth is showered with debris from distant parts of the solar system. When these meteoroids hit the Earth (as meteorites) they range in size from pebbles to the 34 ton Ahnighito meteorite that the American explorer Admiral Robert Peary discovered in Greenland. The unique importance of meteorites is that they have an extra-terrestrial origin and can provide us with direct evidence on the make-up of the solar system. They also give us clues to the origin of the solar system because they formed about 4.6 billion years ago at about the time the planets formed.

  10. 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

  11. Crater Highlands, Tanzania

    Science.gov (United States)

    2006-01-01

    The Shuttle Radar Topography Mission (SRTM), flown aboard Space Shuttle Endeavour in February 2000, acquired elevation measurements for nearly all of Earth's landmass between 60oN and 56oS latitudes. For many areas of the world SRTM data provide the first detailed three-dimensional observation of landforms at regional scales. SRTM data were used to generate this view of the Crater Highlands along the East African Rift in Tanzania. Landforms are depicted with colored height and shaded relief, using a vertical exaggeration of 2X and a southwestwardly look direction. Lake Eyasi is depicted in blue at the top of the image, and a smaller lake occurs in Ngorongoro Crater. Near the image center, elevations peak at 3648 meters (11,968 feet) at Mount Loolmalasin, which is south of Ela Naibori Crater. Kitumbeine (left) and Gelai (right) are the two broad mountains rising from the rift lowlands. Mount Longido is seen in the lower left, and the Meto Hills are in the right foreground. Tectonics, volcanism, landslides, erosion and deposition -- and their interactions -- are all very evident in this view. The East African Rift is a zone of spreading between the African (on the west) and Somali (on the east) crustal plates. Two branches of the rift intersect here in Tanzania, resulting in distinctive and prominent landforms. One branch trends nearly parallel the view and includes Lake Eyasi and the very wide Ngorongoro Crater. The other branch is well defined by the lowlands that trend left-right across the image (below center, in green). Volcanoes are often associated with spreading zones where magma, rising to fill the gaps, reaches the surface and builds cones. Craters form if a volcano explodes or collapses. Later spreading can fracture the volcanoes, which is especially evident on Kitumbeine and Gelai Mountains (left and right, respectively, lower center). The Crater Highlands rise far above the adjacent savannas, capture moisture from passing air masses, and host rain

  12. 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

  13. 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.

  14. 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.

  15. Crater density differences: Exploring regional resurfacing, secondary crater populations, and crater saturation equilibrium on the moon

    Science.gov (United States)

    Povilaitis, R Z; Robinson, M S; van der Bogert, C H; Hiesinger, Harald; Meyer, H M; Ostrach, Lillian

    2017-01-01

    The global population of lunar craters >20 km in diameter was analyzed by Head et al., (2010) to correlate crater distribution with resurfacing events and multiple impactor populations. The work presented here extends the global crater distribution analysis to smaller craters (5–20 km diameters, n = 22,746). Smaller craters form at a higher rate than larger craters and thus add granularity to age estimates of larger units and can reveal smaller and younger areas of resurfacing. An areal density difference map generated by comparing the new dataset with that of Head et al., (2010) shows local deficiencies of 5–20 km diameter craters, which we interpret to be caused by a combination of resurfacing by the Orientale basin, infilling of intercrater plains within the nearside highlands, and partial mare flooding of the Australe region. Chains of 5–30 km diameter secondaries northwest of Orientale and possible 8–22 km diameter basin secondaries within the farside highlands are also distinguishable. Analysis of the new database indicates that craters 57–160 km in diameter across much of the lunar highlands are at or exceed relative crater densities of R = 0.3 or 10% geometric saturation, but nonetheless appear to fit the lunar production function. Combined with the observation that small craters on old surfaces can reach saturation equilibrium at 1% geometric saturation (Xiao and Werner, 2015), this suggests that saturation equilibrium is a size-dependent process, where large craters persist because of their resistance to destruction, degradation, and resurfacing.

  16. 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.

  17. 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

  18. 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 ...

  19. 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.

  20. 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

  1. Orson Welles Crater Dunes

    Science.gov (United States)

    2004-01-01

    [figure removed for brevity, see original site] Released 14 April 2004 The Odyssey spacecraft has completed a full Mars year of observations of the red planet. For the next several weeks the Image of the Day will look back over this first mars year. It will focus on four themes: 1) the poles - with the seasonal changes seen in the retreat and expansion of the caps; 2) craters - with a variety of morphologies relating to impact materials and later alteration, both infilling and exhumation; 3) channels - the clues to liquid surface flow; and 4) volcanic flow features. While some images have helped answer questions about the history of Mars, many have raised new questions that are still being investigated as Odyssey continues collecting data as it orbits Mars. This daytime VIS image was collected on November 13, 2003 during the southern summer season in Orson Welles Crater. Image information: VIS instrument. Latitude -0, Longitude 313.4 East (46.6 West). 19 meter/pixel resolution. Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time. NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly

  2. 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.

  3. 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.

  4. 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.

  5. 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

  6. Concerning the meteoritic origin of the Puchezh-Katunki crater

    Science.gov (United States)

    Firsov, L.; Kieffer, S. W.

    1973-01-01

    Criticism of the works of Vardaniants (1961) and Goretskii (1962) regarding the origin of the Puchezh-Katunki crater, and development of a new hypothesis regarding this disturbance. Although Vardaniants defines the Puchezh-Katunki disturbance as a structure of explosive nature and assumes that the explosion originated as a consequence of accumulation of gases in the crystalline basement of the Russian platform, he lacks evidence to qualify this explosion as coming from a depth. Goretskii's tectonic-injection hypothesis attributes the formation of the disturbance to penetration of an intrusion of basic and ultrabasic rocks into the Paleozoic rocks of the platform. It is shown that, even if the intrusion were spread somewhere at depth, it could not account for the extent of the deformation in the disturbance. It is suggested that this disturbance is of meteoritic origin, since the structure and morphology of the region are similar to the sloping conical surface produced by an explosive meteor crater. The energy, mass, and size of the asteroid which could cause such a disturbance are estimated, and it is shown that the probability of the occurrence of an impact of this size is finite over geological time.

  7. Meteoric water alteration of soil and landscapes at Meridiani Planum, Mars

    Science.gov (United States)

    Amundson, Ronald

    2018-04-01

    The geomorphology and geochemistry data gathered by the MER Opportunity at Meridiani Planum is a rich data set relevant to soil research on Mars. Many of the data, particularly with respect to outcrops at Victoria Crater, have been only partially analyzed. Here, the previously published geochemical profile of Endurance Crater is compared to that of Victoria Crater, to understand aspects of the post-depositional aqueous and chemical alteration of the Meridiani land surface. The landsurface bears cracking patterns similar to those produced by multiple episodes of wetting and drying in expansive materials on Earth. The geochemical profiles at both craters are nearly identical, suggesting (using mass balance methods) that a very chemically homogenous sedimentary deposit has been engulfed by the apparent surficial addition of S, Cl, and Br (and associated cations) since exposure to the atmosphere. The chemistry and mineralogy at both locations is one where the most insoluble of the added components resides near the land surface (Ca sulfates), and the more soluble components are concentrated at greater depths in a vertical pattern consistent with their solubility in water. The profiles, when compared to those on Earth (and to physical constraints), are most similar those generated by the downward movement of meteoric water. When this aqueous alteration and soil formation occurred is not well constrained, but the processes occurred between late Noachian (?) to late Amazonian times. The exposure of the Victoria crater walls, which occurred likely less than 107 y ago (late Amazonian), shows the accumulation of dust as well as evidence for aqueous concentration of NaBr and/or CaBr, possibly by deliquescence. By direct comparison to Earth, the regional soil at Meridiani Planum is a Typic Petrogypsid (a sulfate cemented arid soil), bearing similarities to very ancient soils formed in the Atacama Desert of Chile. The amount of water required to produce the soils ranges from a

  8. High mobility of landslides on the Mercury crater rims

    Science.gov (United States)

    Fukuoka, H.; Kadota, N.; Kiritoshi, I.; Sugiyama, H.; Uragami, H.

    2013-12-01

    The NASA's MESSENGER mercury spacecraft was launched by NASA in 2004, and orbital insertion was successfully completed in 2011. Among its scientific instruments, the Mercury Dual Imaging System (MDIS) and the Mercury Laser Altimeter (MLA) are used to extract the mercury terrain topography. This mission revealed various features of the mercury topography with horizontal resolution of 1 km. Up to July 2013, elevation of the north hemisphere terrain had been released on the net (Quickmap: http://messenger-act.actgate.com/msgr_public_released/react_quickmap.html). As reported by previous studies on landslides found on the lunar crater rims (Fukuoka et al., 2011), they showed extremely small H/V = tan (apparent friction) of the movement, even though almost no groundwater could have been expected ever. Authors examined the crater rims in the northern hemisphere of latitude higher than 65 degrees, because the precision of the altitude is higher in the polar and equatorial regions. We found as many similar landslides along the crater rims. Then, in order to compare the mobility of landslides with lunar ones, we have examined the apparent friction (H/T). In most cases, the H/T values of those landslides are between 0.1 and 0.2, like long-runout landslides on the Moon, Mars and Earth. If the rocks on the mercury show the similar friction as rocks on the earth, those values should be higher than 0.5. Possible mechanism of the small H/L could be cumulated shear displacement induced by repeated quakes by meteor impact over billions of years and / or exotic mechanism including tectonic function.

  9. 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

  10. Geology of Lofn Crater, Callisto

    Science.gov (United States)

    Greeley, Ronald; Heiner, Sarah; Klemaszewski, James E.

    2001-01-01

    Lofn crater is a 180-km-diameter impact structure in the southern cratered plains of Callisto and is among the youngest features seen on the surface. The Lofn area was imaged by the Galileo spacecraft at regional-scale resolutions (875 m/pixel), which enable the general geology to be investigated. The morphology of Lofn crater suggests that (1) it is a class of impact structure intermediate between complex craters and palimpsests or (2) it formed by the impact of a projectile which fragmented before reaching the surface, resulting in a shallow crater (even for Callisto). The asymmetric pattern of the rim and ejecta deposits suggests that the impactor entered at a low angle from the northwest. The albedo and other characteristics of the ejecta deposits from Lofn also provide insight into the properties of the icy lithosphere and subsurface configuration at the time of impact. The "target" for the Lofn impact is inferred to have included layered materials associated with the Adlinda multiring structure northwest of Loh and ejecta deposits from the Heimdall crater area to the southeast. The Lofn impact might have penetrated through these materials into a viscous substrate of ductile ice or possibly liquid water. This interpretation is consistent with models of the current interior of Callisto based on geophysical information obtained from the Galileo spacecraft.

  11. 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)

  12. 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.

  13. 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)

  14. Test-field for evaluation of laboratory craters using a Crater Shape-based interpolation crater detection algorithm and comparison with Martian and Lunar impact craters

    Science.gov (United States)

    Salamunićcar, Goran; Lončarić, Sven; Vinković, Dejan; Vučina, Damir; Gomerčić, Mladen; Pehnec, Igor; Vojković, Marin; Hercigonja, Tomislav

    2012-10-01

    Impact craters are some of the most abundant geological features on most lunar and planetary bodies, providing insight into the history and physical processes that shaped their surface. It is therefore not surprising that extensive research has been done in the past on laboratory craters, as well as on crater detection algorithms (CDAs). No prior work has investigated how CDAs can assist in the research of laboratory craters, nor has an alternative formal method for evaluation of the similarity between laboratory and real impact craters been proposed. The result of this work is a test-field for evaluation of laboratory craters which includes: (1) a procedure for creation of explosion-induced laboratory craters in stone powder surfaces; (2) a method for 3D scanning of laboratory craters using a GOM-ATOS-I 3D scanner; (3) a new method for emplacement of laboratory craters into the topography of a planetary body; (4) a new method for objective evaluation of laboratory craters which utilizes the CDA, the Turing test, and a new measure of similarity between laboratory and real craters; and (5) a possibility of accompanying manual evaluation of laboratory craters using 2D topographical profiles. The successful verification of the proposed test-field, using Martian and Lunar global DEMs and local high-resolution DEMs, confirmed possibilities for the proposed scientific investigations of real impact craters using laboratory craters as proxies. This cost-effective approach also promises affordable accessibility for introductory physics and astronomy laboratories.

  15. 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

  16. 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

  17. 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.

  18. 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.

  19. 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)

  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 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.

  2. 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...

  3. 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

  4. 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...

  5. 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.

  6. 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.

  7. 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

  8. 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.

  9. 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

  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. Oxygen isotopes as tracers of tektite source rocks: An example from the Ivory Coast tektites and Lake Bosumtwi Crater

    Science.gov (United States)

    Blum, Joel D.; Koeberl, Christian; Chamberlain, C. Page

    1993-01-01

    Oxygen isotope studies of tektites and impact glasses provide an important tool to help in identifying the target lithologies for terrestrial impacts, including the K-T boundary impact. However, such studies may be complicated by modification of the original oxygen isotope values of some source rocks during the tektite formation process either by vapor fractionation or incorporation of meteoric water. To further investigate the relationship between the oxygen isotopic composition of tektites and their source rocks, Ivory Coast tektites and samples of impact glasses and bedrock lithologies from the Bosumtwi Crater in Ghana--which is widely believed to be the source crater for the Ivory Coast tektites--were studied. Our preliminary results suggest that the phyllites and metagraywackes from the Bosumtwi Crater were the predominant source materials for the impact glasses and tektites and that no significant oxygen isotope modification (less than 1 percent delta(O-18)) took place during impact melting. This contrasts with previous studies of moldavites and Australasian tektites and their sedimentary source materials which suggests a 4 to 5 percent lowering of delta(O-18) due to meteoric water incorporation during impact melting.

  13. 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.

  14. 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)

  15. Size-Frequency Distribution of Small Lunar Craters: Widening with Degradation and Crater Lifetime

    Science.gov (United States)

    Ivanov, B. A.

    2018-01-01

    The review and new measurements are presented for depth/diameter ratio and slope angle evolution during small ( D impact craters aging (degradation). Comparative analysis of available data on the areal cratering density and on the crater degradation state for selected craters, dated with returned Apollo samples, in the first approximation confirms Neukum's chronological model. The uncertainty of crater retention age due to crater degradational widening is estimated. The collected and analyzed data are discussed to be used in the future updating of mechanical models for lunar crater aging.

  16. The self-secondary crater population of the Hokusai crater on Mercury

    Science.gov (United States)

    Xiao, Zhiyong; Prieur, Nils C.; Werner, Stephanie C.

    2016-07-01

    Whether or not self-secondaries dominate small crater populations on continuous ejecta deposits and floors of fresh impact craters has long been a controversy. This issue potentially affects the age determination technique using crater statistics. Here the self-secondary crater population on the continuous ejecta deposits of the Hokusai crater on Mercury is unambiguously recognized. Superposition relationships show that this population was emplaced after both the ballistic sedimentation of excavation flows and the subsequent veneering of impact melt, but it predated the settlement and solidification of melt pools on the crater floor. Fragments that formed self-secondaries were launched via impact spallation with large angles. Complex craters on the Moon, Mercury, and Mars probably all have formed self-secondaries populations. Dating young craters using crater statistics on their continuous ejecta deposits can be misleading. Impact melt pools are less affected by self-secondaries. Overprint by subsequent crater populations with time reduces the predominance of self-secondaries.

  17. 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)

  18. Revisiting the crater of doom

    Science.gov (United States)

    de Régules, Sergio

    2015-09-01

    The Chicxulub impact structure in Mexico is widely believed to be the site of the asteroid impact that allegedly killed the dinosaurs. As Sergio de Régules reports, scientists are now preparing to glean from it new insights into crater formation, materials science and the mechanisms of mass extinction.

  19. An upper limit on Early Mars atmospheric pressure from small ancient craters

    Science.gov (United States)

    Kite, E. S.; Williams, J.; Lucas, A.; Aharonson, O.

    2012-12-01

    Planetary atmospheres brake, ablate, and disrupt small asteroids and comets, filtering out small hypervelocity surface impacts and causing fireballs, airblasts, meteors, and meteorites. Hypervelocity craters Earth are typically caused by irons (because stones are more likely to break up), and the smallest hypervelocity craters near sea-level on Earth are ~20 m in diameter. 'Zap pits' as small as 30 microns are known from the airless moon, but the other airy worlds show the effects of progressively thicker atmospheres:- the modern Mars atmosphere is marginally capable of removing >90% of the kinetic energy of >240 kg iron impactors; Titan's paucity of small craters is consistent with a model predicting atmospheric filtering of craters smaller than 6-8km; and on Venus, craters below ~20 km diameter are substantially depleted. Changes in atmospheric CO2 concentration are believed to be the single most important control on Mars climate evolution and habitability. Existing data requires an early epoch of massive atmospheric loss to space; suggests that the present-day rate of escape to space is small; and offers only limited evidence for carbonate formation. Existing evidence has not led to convergence of atmosphere-evolution models, which must balance poorly understood fluxes from volcanic degassing, surface weathering, and escape to space. More direct measurements are required in order to determine the history of CO2 concentrations. Wind erosion and tectonics exposes ancient surfaces on Mars, and the size-frequency distribution of impacts on these surfaces has been previously suggested as a proxy time series of Mars atmospheric thickness. We will present a new upper limit on Early Mars atmospheric pressure using the size-frequency distribution of 20-100m diameter ancient craters in Aeolis Dorsa, validated using HiRISE DTMs, in combination with Monte Carlo simulations of the effect of paleo-atmospheres of varying thickness on the crater flux. These craters are

  20. Low H/V and its volume dependency of landslides on the lunar crater rims

    Science.gov (United States)

    Fukuoka, H.; Akao, H.; Miyauchi, D.; Okamoto, A.; Kawase, T.; Ichimura, M.; Chifu, D.; Inui, K.

    2012-04-01

    The Selene lunar orbiter which was launched by JAXA in 2007 brought about a lot of topographical data using laser altimeter (LALT), terrain (wide-view) camera, and HD TV camera. This mission obtained detailed topographic data of lunar terrain with highest spatial resolution of about 10 m. Evaluated precision is about 4 m, and the positioning precision is about 80 m (1 Standar deviation). Most of the obtained topographic data are implemented in Google Moon, which are available in the public for free of charge. JAXA revealed that there are numerous landslide topography especially along the lunar crater rims. In order to compare the mobility of those in Mars, we have examined the apparent friction (H/T) in major craters. Apparently, those landslides are distributed on rather older and dissected crater rims. It means their occurrence must be much later than the crater formation. In most cases, the H/T values of those landslides are around 0.1, like long-runout landslides on the Mars and Earth. Rough estimation of the volume of those landslides implies H/V dependency on volume, i.e. larger landslides shows smaller H/V. The trend is very similar to the ones published by Scheidegger and Hsu. Past studies proved that ground water might have taken most important role in the presence of such low H/L landslide events on the earth and Mars due to excess pore water pressure generation under undrained loading condition of saturated ground soils. However, there have been no evidence nor implication reported, of past water existence on the moon. Possible mechanisms of these low H/T on the crater are (1) moon quake due to nearby meteor impact; (2) shear resistance reduction due to long-term physical/chemical weathering and existence of little ground water; (3) exotic mechanism including tectonic function.

  1. Blocky craters: implications about the lunar megaregolith

    International Nuclear Information System (INIS)

    Thompson, T.W.; Roberts, W.J.; Hartmann, W.K.; Shorthill, R.W.; Zisk, S.H.

    1979-01-01

    Radar, infrared, and photogeologic properties of lunar craters have been studied to determine whether there is a systematic difference in blocky craters between the maria and terrae and whether this difference may be due to a deep megaregolith of pulverized material forming the terra surface, as opposed to a layer of semi-coherent basalt flows forming the mare surface. Some 1310 craters from about 4 to 100 km diameter have been catalogued as radar and/or infrared anomalies. In addition, a study of Apollo Orbital Photography confirmed that the radar and infrared anomalies are correlated with blocky rubble around the crater. Analysis of the radar and infrared data indicated systematic terra-mare differences. Fresh terra craters smaller than 12 km were less likely to be infrared and radar anomalies than comparable mare craters: but terra and mare craters larger than 12 km had similar infrared and radar signatures. Also, there are many terra craters which are radar bright but not infrared anomalies. The authors interpretation of these data is that while the maria are rock layers (basaltic flow units) where craters eject boulder fields, the terrae are covered by relatively pulverized megaregolith at least 2 km deep, where craters eject less rocky rubble. Blocky rubble, either in the form of actual rocks or partly consolidated blocks, contributes to the radar and infrared signatures of the crater. However, aging by impacts rapidly destroys these effects, possibly through burial by secondary debris or by disintegration of the blocks themselves, especially in terra regions. (Auth.)

  2. On shaping of craters at ion bombardment

    International Nuclear Information System (INIS)

    Kalinichenko, A.I.; Perepelkin, S.S.; Strel'nitskij, V.E.

    2013-01-01

    Effect of plasticity and surface tension of metal on form and size of crater produced by heavy low-energy ion is theoretically investigated. Crater is approximated by an axially-symmetrical hollow. The hollow is characterized by known volume and two radii which specify curvatures of both bottom and peripheral parts of crater. Radii of curvature are determined by equality of surface tension forces and elastic reaction of metal. Equations for crater depth and diameter as well as for coefficient of increase of free surface ? due to crater and droplet formation are derived. Dependences of crater form and size on yield strength and surface tension coefficient of metal are analyzed. Influence of specified characteristics on possibility of droplet sputtering and nanometer-sized craters formation at ion bombardment of metals is shown.

  3. Remote Sensing of the Haughton Impact Structure (HIS): A Terrestrial Proof of Concept for Using the Remote Sensing of Martian Craters as a Probe of Subsurface Composition

    Science.gov (United States)

    Tornabene, L. L.; Osinski, G. R.; Moersch, J. E.; Lee, P.

    2004-01-01

    Impact cratering is the most widespread geological process in the Solar System. Impact craters can provide 'windows' into the subsurfaces of planetary bodies through excavation and uplift. By utilizing remote methods in the visible and near infrared (VNIR; 0.4-1.4 micron), short-wavelength infrared (SWIR; 1.4-2.5 micron) and thermal infrared (TIR 7-14 micron), subsurface mineral compositions may be identified and mapped via impact craters. Complex craters in particular, expose minerals from both the shallow and deep-seated subsurface, which may be identified spectroscopically. Complex craters have morphological features such as central peaks or peak rings, which are composed of relatively coherent lithologies tapped from deep-seated crustal components. While near-surface crustal components can be observed as coherent rocks uplifted and exposed in the rim and the crater walls, and from the ejecta deposits. Only two previously published studies using this approach have been successful on large planetary bodies. Tompkins and Pieters utilized ultraviolet and VNIR from Clementine to characterize near- and deep-subsurface materials in and around lunar craters. The work of Ramsey and Wright was the first remote spectroscopic study to successfully identify near-subsurface materials in the ejecta and crater wall of a terrestrial impact structure, namely Meteor Crater. Here we present early results of a third such study, a remote spectroscopy evaluation of the Haughton impact structure (HIS). The purpose of this study is to serve as terrestrial proof of concept that remote visible/infrared spectroscopic methods in this case, analysis of LANDSAT 7 ETM+ and ASTER data of the well-preserved HIS can be utilized in deciphering the subsurface composition of planetary crusts. This technique is particularly promising for Mars were limited tectonic uplift and ubiquitous dust-mantling offer few opportunities to access subsurface information.

  4. 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.

  5. 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...

  6. 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.

  7. 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.

  8. 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.

  9. Using quantitative topographic analysis to understand the role of water on transport and deposition processes on crater walls

    Science.gov (United States)

    Palucis, Marisa Christina

    The amount of water runoff need to evolve landscapes is rarely assessed. Empirical studies correlate erosion rate to runoff or mean annual precipitation, but rarely is the full history of a landscape known such that it is possible to assess how much water was required to produce it. While this may not seem to be of primary importance on Earth where water is commonly plentiful, on Mars the amount of water to drive landscape evolution is a key question. Here we tackle this question through a series of five chapters, one devoted to field work at Meteor Crater, another to laboratory experiments about controlling processes, and then two chapters on analysis of landforms and implications of water runoff on Mars (associated with the Mars Science Laboratory mission to Gale Crater), and then we complete this effort with a consideration of how we can reliably assign relative timing between events resulting in small depositional features. What follows below is a summary of what is found in each chapter. Meteor Crater, a 4.5 km2 impact crater that formed ˜50,000 years ago in northern Arizona, has prominent gully features on its steep walls that appear similar to some gullies found on Mars. At the crater bottom, there are over 30 meters of lake sediments from a lake that disappeared ˜10,000 to 11,000 years ago, indicating the transition from the Pleistocene to the current, drier climate. A combination of fieldwork, cosmogenic dating, and topographic analysis of LiDAR data show that debris flows, not seepage erosion and fluvial processes as previously suggested in the literature, drove gully incision during their formation period of ˜40,000 years before the onset of the Holocene. Runoff from bare bedrock source areas high on the crater wall cut into lower debris mantled slopes, where the runoff bulked up and transformed into debris flows that carried boulders down to ˜5 to 8 degree slopes, leaving distinct boulder lined levees and lobate tongues of terminal debris deposits

  10. Wildfires Caused by Formation of Small Impact Craters: A Kaali Crater Case

    Science.gov (United States)

    Losiak, Anna; Belcher, Claire; Hudspith, Victoria; Zhu, Menghua; Bronikowska, Malgorzata; Jõeleht, Argo; Plado, Juri

    2016-04-01

    Formation of ~200-km Chicxulub 65 Ma ago was associated with release of significant amount of thermal energy [1,2,3] which was sufficient to start wildfires that had either regional [4] or global [5] range. The evidence for wildfires caused by impacts smaller than Chicxulub is inconclusive. On one hand, no signs of fires are associated with the formation of 24-km Ries crater [6]. On the other hand, the Tunguska site was burned after the impact and the numerical models of the bolide-produced thermal radiation suggest that the Tunguska-like event would produce a thermal flux to the surface that is sufficient to ignite pine needles [7]. However, in case of Tunguska the only proof for the bolide starting the fire comes from an eyewitness description collected many years after the event. Some authors [8] suggest that this fire might have been caused "normaly" later during the same year, induced on dead trees killed by the Tunguska fall. More recently it was observed that the Chelyabinsk meteor [9] - smaller than Tunguska event - did not produced a fire. In order to explore this apparent relationship in more detail, we have studied the proximal ejecta from a 100-m in diameter, ~3500 years old [10] Kaali crater (Estonia) within which we find pieces of charred organic material. Those pieces appear to have been produced during the impact, according to their stratigraphic location and following 14C analysis [19] as opposed to pre- or post-impact forest fires. In order to determine the most probable formation mechanism of the charred organic material found within Kaali proximal ejecta blanket, we: 1) Analyzed charcoal under SEM to identify the charred plants and determine properties of the charcoal related to the temperature of its formation [11]. Detected homogenization of cell walls suggests that at least some pieces of charcoal were formed at >300 °C [11]. 2) Analyzed the reflectance properties of the charred particles in order to determine the intensity with which

  11. Crater Degradation on Mercury: A Global Perspective

    Science.gov (United States)

    Kinczyk, M. J.; Byrne, P. K.; Prockter, L. M.; Susorney, H. C. M.; Chapman, C. R.; Barnouin, O. S.

    2017-12-01

    On geologic timescales, initially fresh craters are subjected to many weathering mechanisms. Whereas water and wind are, or were, effective erosive mechanisms such as on Earth and Mars, micrometeorite bombardment and modification due to subsequent impacts are the dominant processes that degrade craters and crater rays on airless bodies like the Moon and Mercury. Classifying craters based on their state of degradation can help determine the relative ages of landforms proximal to, and crosscut by, these craters. However, this method is most effective when used together with statistical analysis of crater distributions. Pre-MESSENGER degradation classification schemes lacked sufficient detail to be consistently applied to craters of various sizes and morphological types—despite evidence suggesting that the ejecta deposits of large basins persist much longer than those of smaller craters, for instance—yet broad assumptions have been made regarding the correlation of crater class to the planet's time-stratigraphic sequence. Moreover, previous efforts to categorize craters by degradation state have either been restricted to regional study sites or applied only to a subset of crater age or size. As a result, numerous interpretations of crater degradation state persist for Mercury, challenging a complete understanding of this process on the innermost planet. We report on the first global survey of crater degradation on Mercury. By modifying an established 5-class scheme, we have systematically applied a rigorous set of criteria to all craters ≥40 km in diameter on the planet. These criteria include the state and morphology of crater deposits separately (e.g., rim, floor, wall, ejecta) and degradation classes were assigned as the collection of these individual attributes. This approach yields a consistent classification of craters of different sizes. Our results provide the first comprehensive assessment of how craters of various states of degradation are distributed

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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)

  18. 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.

  19. Impact Craters: Size-Dependent Degration Rates

    Science.gov (United States)

    Ravi, S.; Mahanti, P.; Meyer, H. M.; Robinson, M. S.

    2017-12-01

    From superposition relations, Shoemaker and Hackman (1) devised the lunar geologic timescale with Copernican and Eratosthenian as the most recent periods. Classifying craters into the two periods is key to understanding impactor flux and regolith maturation rates over the last 3 Ga. Both Copernican and Eratosthenian craters exhibit crisp morphologies (sharp rims, steep slopes), however, only the former exhibit high reflectance rays and ejecta (1). Based on the Optical Maturity Parameter (OMAT; 2), Grier et al. (3) classified 50 fresh craters (D >20 km) into 3 categories - young (OMAT >0.22), intermediate, and old (OMAT 10) were identified (4) from a catalogue of 11,875 craters (5). In this work; we compare two size ranges (D: 5 km - 10 km and 10 km to 15 km) of 177 Copernican craters based on the average OMAT, measured near the crater rim (3). OMAT is measured at the crater rim (as opposed to further away from the crater) to minimize the influence of spatial variation of OMAT (6) in our investigation. We found that OMAT values are typically lower for smaller craters (5km age, craters with higher d/D value (morphologically fresher) should have higher OMAT, but this is not the case. We propose that quicker loss of OMAT (over time) for smaller craters compared to decrease in d/D with crater ageing, is responsible for the observed decreased OMAT for smaller craters. (1) Shoemaker and Hackman, 1962 (2) Lucey et al., 2000 (3) Grier et al., 2001 (4) Ravi et al., 2016 (5) Reinhold et al., 2015 (6) Mahanti et al., 2016

  20. 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.

  1. 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

  2. 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.

  3. 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.

  4. Clustered impacts - Experiments and implications. [cratering mechanics

    Science.gov (United States)

    Schultz, P. H.; Gault, D. E.

    1985-01-01

    The characteristics of impact by clusters of projectiles are experimentally studied by launching grouped projectiles of aluminum shot, steel shot, iron filings, and sand. Cratering efficiency is considered as a function of a dimensionless parameter related to projectile size and impact velocity. The effects of different target and projectile densities on cratering efficiency are examined. Crater morphology is addressed by considering a typical example, reviewing the systematics between cluster dispersion and crater morphology for vertical impacts, and examining oblique angle impacts which have relevance for planetary secondary cratering processes. These results are compared with impacts by single bodies with different strengths. The evolution of the ejecta plume for clustered impacts is compared to that for single-body impacts for vertical and oblique impacts from 1.3 to 1.8 km/s. The experimental results are discussed in the context of planetary surface processes, emphasizing processes in an atmosphere-free environment and secondary impact cratering.

  5. Defrosting of Russell Crater Dunes

    Science.gov (United States)

    2007-01-01

    These two images (at right) were acquired by the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) 39 days apart at 19:10 UTC (2:10 PM EST) on December 28, 2006 (upper right) and at 20:06 UTC (3:06 PM EST) on February 5, 2007 (lower right). These CRISM data were acquired in 544 colors covering the wavelength range from 0.36-3.92 micrometers, and show features as small as 20 meters (about 65 feet) across. Both images are false color composites of bands at 2.5, 1.5, and 1.25 micrometers, and are nearly centered at the same location, 54.875oS, 12.919oE (upper right) and 54.895oS, 12.943oE (lower right). Each image is approximately 11 kilometers (7 miles) across at its narrowest. These are part of a series of images capturing the evolution of carbon dioxide frost on the surface of the dunes in Russell Crater. Russell Crater is one of many craters in the southern highland region of Mars that contain large areas of sand dunes. The sand in these dunes has accumulated over a very long time period -- perhaps millions of years -- as wind blows over the highland terrain, picking up sand in some places and depositing in others. The topography of the craters forces the wind to blow up and over the crater rims, and the wind often isn't strong enough to keep the tiny grains suspended. This makes the sand fall to the ground and gradually pile up, and over time the surface breezes shape the sand into ripples and dunes. A similar process is at work at the Great Sand Dunes National Park and Preserve in Colorado, USA. The above left image shows a THEMIS daytime infrared mosaic of Russell Crater and the location of its (approximately) 30-kilometer wide dune field in the northeastern quadrant of the crater floor. Superposed on this view and shown enlarged at the upper right is CRISM image FRT000039DF. This CRISM image was acquired during the late Martian southern winter (solar longitude = 157.7o), and the bright blue in this false color composite indicates the presence of

  6. What Really Happened to Earth's Older Craters?

    Science.gov (United States)

    Bottke, William; Mazrouei, Sara; Ghent, Rebecca; Parker, Alex

    2017-10-01

    Most assume the Earth’s crater record is heavily biased, with erosion/tectonics destroying older craters. This matches expectations, but is it actually true? To test this idea, we compared Earth’s crater record, where nearly all D ≥ 20 km craters are ages were computed using a new method employing LRO-Diviner temperature data. Large lunar rocks have high thermal inertia and remain warm through the night relative to the regolith. Analysis shows young craters with numerous meter-sized fragments are easy to pick out from older craters with eroded fragments. Moreover, an inverse relationship between rock abundance (RA) and crater age exists. Using measured RA values, we computed ages for 111 rocky craters with D ≥ 10 km that formed between 80°N and 80°S over the last 1 Gyr.We found several surprising results. First, the production rate of D ≥ 10 km lunar craters increased by a factor of 2.2 [-0.9, +4.4; 95% confidence limits] over the past 250 Myr compared to the previous 750 Myr. Thus, the NEO population is higher now than it has been for the last billion years. Second, the size and age distributions of lunar and terrestrial craters for D ≥ 20 km over the last 650 Myr have similar shapes. This implies that crater erasure must be limited on stable terrestrial terrains; in an average sense, for a given region, the Earth either keeps all or loses all of its D ≥ 20 craters at the same rate, independent of size. It also implies the observed deficit of large terrestrial craters between 250-650 Myr is not preservation bias but rather reflects a distinctly lower impact flux. We predict 355 ± 86 D ≥ 20 km craters formed on Earth over the last 650 Myr. Only 38 ± 6 are known, so the ratio, 10.7 ± 3.1%, is a measure of the Earth’s surface that is reasonably stable to large crater formation over 650 Myr. If erosion had dominated, the age distribution of terrestrial craters would be strongly skewed toward younger ages, which is not observed. We predict

  7. Spectroscopic Observations of the 2011 Draconids Meteor Shower

    Czech Academy of Sciences Publication Activity Database

    Rudawska, R.; Zender, J.; Jenniskens, P.; Vaubaillon, J.; Koten, Pavel; Margonis, A.; Toth, J.; McAuliffe, J.; Koschny, D.

    2014-01-01

    Roč. 112, 1-4 (2014), s. 45-57 ISSN 0167-9295 R&D Projects: GA ČR GA205/09/1302 Institutional support: RVO:67985815 Keywords : meteorites * meteors * meteoroids Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 0.667, year: 2014

  8. The 2011 Draconids: The First European Airborne Meteor Observation Campaign

    Czech Academy of Sciences Publication Activity Database

    Vaubaillon, J.; Koten, Pavel; Margonis, A.; Toth, J.; Rudawska, R.; Gritsevich, M.; Zender, J.; McAuliffe, J.; Pautet, D.; Jenniskens, P.; Koschny, D.; Colas, F.; Bouley, S.; Maquet, L.; Leroy, A.; Lecacheux, J.; Borovička, Jiří; Watanabe, J.; Oberst, J.

    2015-01-01

    Roč. 114, 3-4 (2015), s. 137-157 ISSN 0167-9295 R&D Projects: GA ČR GA14-25251S Institutional support: RVO:67985815 Keywords : meteors * Draconids * 21P/Giacobini-Zinner Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 0.659, year: 2015

  9. Photometry of 1998/1999 Persistent Trails from Leonid Meteors

    Science.gov (United States)

    Milster, S. P.; Grime, B.; Drummond, J.; Fugate, R.; Kane, T. J.; Liu, A.; Papen, C. S.; Kelly, M. C.; Kruschwitz, C.

    2000-05-01

    Surface brightness and line emission rates are derived for two persistent trails from the 1998 and 1999 Leonid meteor showers. The trails are optically thin, and in places appear as cylinders with a very dark center. This center is roughly as wide as the bright emission walls, but is as dark as the sky background. This situation is not in agreement with the simple hollow-cylinder model of shell burning. The data was acquired at the Starfire Optical Range on Kirtland AFB. The instruments were guided by a human observer onto the lingering trails of the meteors. A 5 degree wide Xybion camera, attached to the headring of the telescope, recorded the scene. The University of Illinois' sodium lidar determined the distance to the persistent trails. A 200-W copper vapor laser (CVL) was also used in an attempt to measure back-scatter from particulates in the contrails of the Leonids. Almost all of the meteors that produced lingering trails greatly enhanced the naturally occurring sodium layer at 100 km. The lingering trails generally appeared as evanescent smoke rings that evolved rather quickly, with the path of the meteor marked by a double walled, optically thin tube. A 15-minute highlight video will be presented showing the evolution of the lingering trails as well as the lidar and the CVL probing them.

  10. Building single-page web apps with meteor

    CERN Document Server

    Vogelsteller, Fabian

    2015-01-01

    If you are a web developer with basic knowledge of JavaScript and want to take on Web 2.0, build real-time applications, or simply want to write a complete application using only JavaScript and HTML/CSS, this is the book for you.This book is based on Meteor 1.0.

  11. CAMS newly detected meteor showers and the sporadic background

    Science.gov (United States)

    Jenniskens, P.; Nénon, Q.; Gural, P. S.; Albers, J.; Haberman, B.; Johnson, B.; Morales, R.; Grigsby, B. J.; Samuels, D.; Johannink, C.

    2016-03-01

    The Cameras for Allsky Meteor Surveillance (CAMS) video-based meteoroid orbit survey adds 60 newly identified showers to the IAU Working List of Meteor Showers (numbers 427, 445-446, 506-507, and part of 643-750). 28 of these are also detected in the independent SonotaCo survey. In total, 230 meteor showers and shower components are identified in CAMS data, 177 of which are detected in at least two independent surveys. From the power-law size frequency distribution of detected showers, we extrapolate that 36% of all CAMS-observed meteors originated from ∼700 showers above the N = 1 per 110,000 shower limit. 71% of mass falling to Earth from streams arrives on Jupiter-family type orbits. The transient Geminids account for another 15%. All meteoroids not assigned to streams form a sporadic background with highest detected numbers from the apex source, but with 98% of mass falling in from the antihelion source. Even at large ∼7-mm sizes, a Poynting-Robertson drag evolved population is detected, which implies that the Grün et al. collisional lifetimes at these sizes are underestimated by about a factor of 10. While these large grains survive collisions, many fade on a 104-y timescale, possibly because they disintegrate into smaller particles by processes other than collisions, leaving a more resilient population to evolve.

  12. Feasibility Study Utilizing Meteor Burst Communications for Vessel Monitoring

    Science.gov (United States)

    1981-11-01

    4. EQUIPMENT The two meteor burst systems considered are the AMBCS with its Master Station located at Anchorage and an existing mobile government owned...requirement. However, since the mobile government owned system was specifi- cally designed for flight following applications, the transi- tion to ship

  13. Optical Meteor Fluxes and Application to the 2015 Perseids

    Science.gov (United States)

    Blaauw, R. C.; Campbell-Brown, M.; Kingery, A.

    2016-01-01

    This paper outlines new methods to measure optical meteor fluxes for showers and sporadic sources. Many past approaches have found the collecting area of a detector at a fixed 100 km altitude, but this approach considers the full volume, finding the area in two km height intervals based on the position of the shower or sporadic source radiant and the population's velocity. Here, the stellar limiting magnitude is found every 10 minutes during clear periods and converted to a limiting meteor magnitude for the shower or sporadic source having fluxes measured, which is then converted to a limiting mass. The final output is a mass limited flux for meteor showers or sporadic sources. Presented are the results of these flux methods as applied to the 2015 Perseid meteor shower as seen by the Meteoroid Environment Office's eight wide-field cameras. The peak Perseid flux on the night of August 13, 2015, was measured to be 0.002989 meteoroids/km2/hr down to 0.00051 grams, corresponding to a ZHR of 100.7.

  14. Dispersion of meteor trails in the geomagnetic field.

    Science.gov (United States)

    Robson, R E

    2001-02-01

    A meteor trail is modeled by a long column of weakly ionized plasma, whose dispersion is controlled by the geomagnetic field and the requirement to maintain effective space charge neutrality. First we consider scattering of a radar signal from an underdense trail and derive an expression for the amplitude of the backscattered signal as a function of time. Then, starting from the basic momentum balance equations for electrons and ions in a partially ionized plasma, we require divergences of ion and electron fluxes to be equal, plus assume equality of the flux components along the magnetic field direction. The analysis is really applicable to a whole range of plasma problems, although we focus upon meteor trails for now. It is found that charged particle densities satisfy a diffusion equation and we obtain an expression for the ambipolar diffusion tensor and expressions for the ambipolar electric field, valid for arbitrary relative orientations of the magnetic field and meteor trail axis. Results are somewhat different from previous analyses in the meteor literature.

  15. The 2017 Meteor Shower Activity Forecast for Earth Orbit

    Science.gov (United States)

    Moorhead, Althea; Cooke, Bill; Moser, Danielle

    2017-01-01

    Most meteor showers will display typical activity levels in 2017. Perseid activity is expected to be higher than normal but less than in 2016; rates may reach 80% of the peak ZHR in 2016. Despite this enhancement, the Perseids rank 4th in flux for 0.04-cm-equivalent meteoroids: the Geminids (GEM), Daytime Arietids (ARI), and Southern delta Aquariids (SDA) all produce higher fluxes. Aside from heightened Perseid activity, the 2017 forecast includes a number of changes. In 2016, the Meteoroid Environment Office used 14 years of shower flux data to revisit the activity profiles of meteor showers included in the annual forecast. Both the list of showers and the shape of certain major showers have been revised. The names and three-letter shower codes were updated to match those in the International Astronomical Union (IAU) Meteor Data Center, and a number of defunct or insignificant showers were removed. The most significant of these changes are the increased durations of the Daytime Arietid (ARI) and Geminid (GEM) meteor showers. This document is designed to supplement spacecraft risk assessments that incorporate an annual averaged meteor shower flux (as is the case with all NASA meteor 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 damage. These two showers, along with the Quadrantids (QUA) and Perseids (PER), exceed the baseline flux for 0.3-cm-equivalent particles, which is near the limit for pressure vessel penetration. Please note, however, that meteor shower fluxes drop dramatically with increasing particle size. As an example, the Arietids contribute a flux of about 5x10(exp -6) meteoroids m(exp -2) hr-1 in the 0.04-cm-equivalent range, but only 1x10(exp -8) meteoroids m(sub -2) hr-1 for the 0

  16. A synthetical index of the potential threats about intense activities of meteors

    Science.gov (United States)

    Wu, Guang-jie

    2006-10-01

    In the present age, several techniques for the application to the observation of meteors and meteor showers have been developed in modern meteor astronomy. The initial definition for a meteor storm based on the visual observation with a Zenithal Hourly Rate of above 1000 seems insufficient now, since it only means a storm or burst of meteors in numbers and means that an eyewitness could have a chance to see a spectacular meteor show. Up to now, peoples have also recorded the meteoric flashes on the Moon during the Leonid meteor showers. Especially, the increasing activities of mankind in space for scientific, commercial and military purposes, have led to an increase in the problems concerning the safety of the satellites, space stations and astronauts. How the intense activity of a meteor storm is defined and forecast, some new points of view are needed. In this paper, several aspects about the intensity of the meteor storm are analyzed, including the number, mass, impulse, energy, electric charge, different purposes and different physical meanings. Finally, a synthetical index denoting the activity and potential threat of an intense meteor shower is suggested.

  17. Dark Valley in Newton Crater

    Science.gov (United States)

    2003-01-01

    MGS MOC Release No. MOC2-418, 11 July 2003This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) high resolution image shows part of a dark-floored valley system in northern Newton Crater. The valley might have been originally formed by liquid water; the dark material is probably sand that has blown into the valley in more recent times. The picture was acquired earlier this week on July 6, 2003, and is located near 39.2oS, 157.9oW. The picture covers an area 2.3 km (1.4 mi) across; sunlight illuminates the scene from the upper left.

  18. Impact craters in South America

    CERN Document Server

    Acevedo, Rogelio Daniel; Ponce, Juan Federico; Stinco, Sergio G

    2015-01-01

    A complete and updated catalogue of impact craters and structures in South America from 2014 is presented here. Approximately eighty proven, suspected and disproven structures have been identified by several sources in this continent. All the impact sites of this large continent have been exhaustively reviewed: the proved ones, the possible ones and some very doubtful. Many sites remain without a clear geological ""in situ"" confirmation and some of them could be even rejected. Argentina and Brazil are leading the list containing almost everything detected. In Bolivia, Chile, Colombia, Guyana,

  19. Video and photometric observations of a sprite in coincidence with a meteor-triggered jet event

    International Nuclear Information System (INIS)

    Suszcynsky, D. M.; Strabley, R.; Roussel-Dupre, R.; Symbalisty, E. M. D.; Armstrong, R. A.; Lyons, W. A.; Taylor, M.

    1999-01-01

    Video and photometric observations of a meteor-triggered ''jet'' event in association with the occurrence of a sprite were collected during the SPRITES '98 campaign. The event raises interest in the question of possible meteoric triggering of upper atmospheric transients as originally suggested by Muller [1995]. The event consisted of three stages: (1) the observation of a moderately bright meteor, (2) the development of a sprite in the immediate vicinity of the meteor as the meteor reached no lower than ∼70 km altitude, and (3) a slower-forming jet of luminosity that appeared during the late stages of the sprite and propagated back up the ionization trail of the meteor. The event is analyzed in terms of its geometry, its relevance to the meteor, and the implications to existing theories for sprite formation. (c) 1999 American Geophysical Union

  20. Application of high explosion cratering data to planetary problems

    Science.gov (United States)

    Oberbeck, V. R.

    1977-01-01

    The present paper deals with the conditions of explosion or nuclear cratering required to simulate impact crater formation. Some planetary problems associated with three different aspects of crater formation are discussed, and solutions based on high-explosion data are proposed. Structures of impact craters and some selected explosion craters formed in layered media are examined and are related to the structure of lunar basins. The mode of ejection of material from impact craters is identified using explosion analogs. The ejection mode is shown to have important implications for the origin of material in crater and basin deposits. Equally important are the populations of secondary craters on lunar and planetary surfaces.

  1. Hydrothermal Alteration at Lonar Crater, India and Elemental Variations in Impact Crater Clays

    Science.gov (United States)

    Newsom, H. E.; Nelson, M. J.; Shearer, C. K.; Misra, S.; Narasimham, V.

    2005-01-01

    The role of hydrothermal alteration and chemical transport involving impact craters could have occurred on Mars, the poles of Mercury and the Moon, and other small bodies. We are studying terrestrial craters of various sizes in different environments to better understand aqueous alteration and chemical transport processes. The Lonar crater in India (1.8 km diameter) is particularly interesting being the only impact crater in basalt. In January of 2004, during fieldwork in the ejecta blanket around the rim of the Lonar crater we discovered alteration zones not previously described at this crater. The alteration of the ejecta blanket could represent evidence of localized hydrothermal activity. Such activity is consistent with the presence of large amounts of impact melt in the ejecta blanket. Map of one area on the north rim of the crater containing highly altered zones at least 3 m deep is shown.

  2. Processes Modifying Cratered Terrains on Pluto

    Science.gov (United States)

    Moore, J. M.

    2015-01-01

    The July encounter with Pluto by the New Horizons spacecraft permitted imaging of its cratered terrains with scales as high as approximately 100 m/pixel, and in stereo. In the initial download of images, acquired at 2.2 km/pixel, widely distributed impact craters up to 260 km diameter are seen in the near-encounter hemisphere. Many of the craters appear to be significantly degraded or infilled. Some craters appear partially destroyed, perhaps by erosion such as associated with the retreat of scarps. Bright ice-rich deposits highlight some crater rims and/or floors. While the cratered terrains identified in the initial downloaded images are generally seen on high-to-intermediate albedo surfaces, the dark equatorial terrain informally known as Cthulhu Regio is also densely cratered. We will explore the range of possible processes that might have operated (or still be operating) to modify the landscape from that of an ancient pristinely cratered state to the present terrains revealed in New Horizons images. The sequence, intensity, and type of processes that have modified ancient landscapes are, among other things, the record of climate and volatile evolution throughout much of the Pluto's existence. The deciphering of this record will be discussed. This work was supported by NASA's New Horizons project.

  3. Response to Tim Barringer, A White Atlantic?

    Directory of Open Access Journals (Sweden)

    Kate Flint

    2009-11-01

    Full Text Available In my response to Tim Barringer’s piece, I emphasize the importance of extending one’s frame of reference when discussing transatlantic artistic connections to the consideration of as many different art forms as possible – including photography, and magazine and book illustrations – in order to get as full a picture as possible of the two-way flow in transatlantic artistic influences.This fuller picture notably extends the degree to which images of non-white subjects are seen to be in circulation. I also draw attention to the ways in which American and English artistic circles intersected outside as well as within these two countries, a point reinforced by looking at American women sculptors in Rome in the 1860s, paying particular attention to the work of the part African-American, part Native American sculptor, Edmonia Lewis. In her work can be seen a complex set of attitudes towards her subject matter that remind one forcefully of the many racial and cultural strands coming together in new American art.

  4. Technical problems and future cratering experiments

    International Nuclear Information System (INIS)

    Knox, J.B.

    1969-01-01

    This paper reviews some of the key technical problems that remain to be solved in nuclear cratering technology. These include: (1) developing a broader understanding of the effects that material properties and water content of the earth materials around the shot have on cratering behavior, (2) extending the experimental investigation of retarc formation to include intermediate yields and various materials, and (3) improving our ability to predict the escape of radioactive material to the atmosphere to form the cloud source responsible for fallout. The formation processes of ejecta craters, retarcs, and subsidence craters are described in the light of our present understanding, and the major gaps in our understanding are indicated. Methods of calculating crater and retarc formation are discussed, with particular reference to the input information needed. Methods for calculating fallout are presented, and their shortcomings are discussed. A preliminary analysis of the safety factors associated with the presently proposed nuclear excavation concepts is presented. (author)

  5. 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

  6. 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

  7. The MAGIC Meteoric Smoke Particle Sampler - Description and Results

    Science.gov (United States)

    Hedin, J.

    2013-12-01

    Between a few to several hundred tons of meteoric material enters the Earth's atmosphere each day, and much of this material ablates in the 70 -130 km region of the atmosphere. Already in the early 1960's it was suggested that meteoroid ablation products could recondense and form solid nanometer-scale smoke particles in the altitude range of the mesosphere and lower thermosphere (MLT). These so-called meteoric smoke particles (MSPs) are then subject to further coagulation, sedimentation, and transport by the mesospheric meridional circulation which in turn determines the latitudinal and seasonal variation of the MSP distribution. MSPs have been suggested to be important for a variety of atmospheric phenomena: 1. they are the most likely candidate for the nuclei of mesospheric ice particles (NLC and PMSE); 2. they provide surface area on which heterogeneous chemical reactions take place and may influence, for example, the water vapor distribution and Ox/HOx chemistry in the mesosphere; 3. they act as ultimate sink in mesospheric metal chemistry by scavenging various gas-phase products of meteoric ablation; 4. they can significantly influence the ionospheric D-region charge balance by scavenging free electrons and positive ions; and 5. they may be involved in the formation of NAT particles in polar stratospheric clouds and the destruction of ozone. Given the above points, it is obvious that there is a large scientific interest in the properties and global distribution of MSPs. Basic information about MSP properties is today available from optical occultation measurements (AIM/SOFIE) and, more indirectly, from in-situ measurements of the charged particle population. In order to understand the role of meteoric smoke particles in the mesosphere and their impact on that environment their presence must be certified and their physical characterization (number density, size distribution, shape, composition etc.) determined. A way to obtain maximum information about particle

  8. International Assistance in Naming Craters on Mercury

    Science.gov (United States)

    Weir, H. M.; Edmonds, J.; Hallau, K.; Hirshon, B.; Goldstein, J.; Hamel, J.; Hamel, S.; Solomon, S. C.

    2015-12-01

    NASA's robotic MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft made history in March 2011 by becoming the first to orbit Mercury. During the mission, MESSENGER acquired more than 250,000 images and made many other kinds of measurements. Names are often given to surface features that are of special scientific interest, such as craters. To draw international attention to the achievements of the spacecraft and engineers and scientists who made the MESSENGER mission a success, the MESSENGER Education and Public Outreach (EPO) Team initiated a Name a Crater on Mercury Competition.Five craters of particular geological interest were chosen by the science team. In accordance with International Astronomical Union (IAU) rules for Mercury, impact craters are named in honor of those who have made outstanding or fundamental contributions to the arts and humanities. He or she must have been recognized as a historically significant figure in the arts for at least 50 years and deceased for the last three years. We were particularly interested in entries honoring people from nations and cultural groups underrepresented in the current list of crater names. From more than 3600 entries received from around the world, the EPO team was able to reduce the number of entries to about 1200 names of 583 different artists who met the contest eligibility criteria. Next, the proposed individuals were divided into five artistic field groups and distributed to experts in that respective field. Each expert reviewed approximately100 artists with their biographical information. They narrowed down their list to a top ten, then to a top five by applying a rubric. The final selection was based on the reviewer lists and scores, with at least three finalist names selected from each artistic field. Of the 17 finalists provided to the IAU, the following names were selected: Carolan crater, Enheduanna crater, Karsh crater, Kulthum crater, and Rivera crater. For more

  9. Investigations of Ceres's Craters with Straightened Rim

    Science.gov (United States)

    Frigeri, A.; De Sanctis, M. C.; Ammannito, E.; Raponi, A.; Formisano, M.; Ciarniello, M.; Magni, G.; Combe, J. P.; Marchi, S.; Raymond, C. A.; Schwartz, S. J.

    2017-12-01

    Dwarf planet Ceres hosts some geological features that are unique in the solar system because its composition, rich in aqueously-altered silicates, is usually found on full-size planets, whereas its mean radius is smaller than most natural satellites in the solar system. For example, the local high-albedo, carbonate-rich areas or faculaeare specific to Ceres; also, the absence of big impact crater structures is key to understand the overall mechanical behaviour of the Cerean crust. After the first findings of water ice occurring in the shadowed areas of craters on Ceres by the NASA/Dawn mission (1, 2), we analyzed the morphology of craters looking for features similar to the ones where the water ice composition has been detected analyzing the data from the VIR spectrometer (3). These craters fall outside of the family of polygonal craters which are mainly related to regional or global scale tectonics (4). We analyzed the morphology on the base of the global mosaic, the digital terrain model derived by using the stereo photogrammetry method and the single data frames of the Framing Camera. Our investigation started from crater Juling, which is characterized by a portion of the rim which forms a straight segment instead of a portion of a circle. This linear crater wall is also steep enough that it forms a cliff that is in the shadowed area in all images acquired by Dawn. Very smooth and bright deposits lay at the foot of this crater-wall cliff. Then, we identified several other craters, relatively fresh, with radius of 2 to 10 kilometers, showing one or two sectors of the crater-rim being truncated by a mass-wasting process, probably a rockfall. Our first analysis show that in the selected craters, the truncated sectors are always in the north-eastern sector of the rim for the craters in the southern hemisphere. Conversely, the craters on the northern hemisphere exhibit a truncated rim in their south-eastern sector. Although a more detailed analysis is mandatory

  10. Character of meteoric leaks in the salt mines of south Louisiana, U.S.A.

    Science.gov (United States)

    Kumar, Madhurendu B.

    1983-10-01

    The brine leaks of salt mines of south Louisiana are of two genetic categories: meteoric and non-meteoric (connate/formation water type), as established essentially on the basis of oxygen- and hydrogen-isotope analyses. This paper highlights the hydrochemical aspects of those mine leaks and develops simple non-isotopic criteria to differentiate the meteoric leaks from the non-meteoric. The meteoric leaks of the salt mines generally occur down to a depth level of 214 m (700 ft.) (below mean sea level) below which the leaks are mostly non-meteoric. The meteoric brine is essentially Na1bCl in type, reflecting the mineralogy of almost pure halite (with ˜ 1-2% anhydrite) of the Gulf (of Mexico) Coast dome salt. The meteoric leaks are distinctly different from the non-meteoric leaks on the log-log plots of chloride concentrations vs. those of Ca 2+, Mg 2+, K +, Sr + and Br -, in all of which the meteoric brines are conspicuously low. This study is potentially useful in the development of a mine or crypt in salt dome(s) under consideration for possible nuclear-waste isolation in the Gulf Coast region.

  11. Development of the mesospheric Na layer at 69° N during the Geminids meteor shower 2010

    Directory of Open Access Journals (Sweden)

    T. Dunker

    2013-01-01

    Full Text Available The ECOMA sounding rocket campaign in 2010 was performed to investigate the charge state and number density of meteoric smoke particles during the Geminids meteor shower in December 2010. The ALOMAR Na lidar contributed to the campaign with measurements of sodium number density, temperature and line-of-sight wind between 80 and 110 km altitude over Andøya in northern Norway. This paper investigates a possible connection between the Geminids meteor shower and the mesospheric sodium layer. We compare with data from a meteor radar and from a rocket-borne in situ particle instrument on three days. Our main result is that the sodium column density is smaller during the Geminids meteor shower than the winter average at the same latitude. Moreover, during two of the three years considered, the sodium column density decreased steadily during these three weeks of the year. Both the observed decrease of Na column density by 30% and of meteoric smoke particle column density correlate well with a corresponding decrease of sporadic meteor echoes. We found no correlation between Geminids meteor flux rates and sodium column density, nor between sporadic meteors and Na column density (R = 0.25. In general, we found the Na column density to be at very low values for winter, between 1.8 and 2.6 × 1013 m−2. We detected two meteor trails containing sodium, on 13 December 2010 at 87.1 km and on 19 December 2010 at 84 km. From these meteor trails, we estimate a global meteoric Na flux of 121 kg d−1 and a global total meteoric influx of 20.2 t d−1.

  12. Listening to sounds from an exploding meteor and oceanic waves

    Science.gov (United States)

    Evers, L. G.; Haak, H. W.

    Low frequency sound (infrasound) measurements have been selected within the Comprehensive Nuclear-Test-Ban Treaty (CTBT) as a technique to detect and identify possible nuclear explosions. The Seismology Division of the Royal Netherlands Meteorological Institute (KNMI) operates since 1999 an experimental infrasound array of 16 micro-barometers. Here we show the rare detection and identification of an exploding meteor above Northern Germany on November 8th, 1999 with data from the Deelen Infrasound Array (DIA). At the same time, sound was radiated from the Atlantic Ocean, South of Iceland, due to the atmospheric coupling of standing ocean waves, called microbaroms. Occurring with only 0.04 Hz difference in dominant frequency, DIA proved to be able to discriminate between the physically different sources of infrasound through its unique lay-out and instruments. The explosive power of the meteor being 1.5 kT TNT is in the range of nuclear explosions and therefore relevant to the CTBT.

  13. A new interpretation of the meteoric water line

    International Nuclear Information System (INIS)

    Wetzel, K.

    1988-01-01

    Simple Rayleigh condensation and Rayleigh evaporation models for evaluating correlation between the isotopic composition of hydrogen and oxygen in meteoric water are analysed in terms of influences of accumulation of conversion products, of mixing of vapour and liquid phases, of extension or contraction, respectively. The effect of simultaneous conversion in both directions can be taken into account by introducing the relative amounts η and (1-η) of condensation and evaporation. The model yields m 7.82 and q = 8.90 instead of the empirically found values m = 8.08 +- 0.80 and q = 9.57 +- 0.62 in the meteoric water line δD = mδ 18 O + q and a satisfactory understanding of the corresponding δD - δ 18 O correlations of the Northern and the Southern hemisphere with their different quantitative proportions of ocean and land masses. (author)

  14. Investigations of characteristics of solar cosmic radiation by ''Meteor'' satellites

    International Nuclear Information System (INIS)

    Pereyaslova, N.K.; Nazarova, M.N.; Petrenko, I.E.

    1983-01-01

    Within the period from 1969 to 1978, 73 proton events of solar cosmic radiation (SCR) in which the proton flux (Esub(p) > 5 MeV) in the event maximum exceed approximatly 10 protonxcm -2 s -1 have been investigated at the ''Meteor'' satellite in high-latitude regions of the Earth magnetosphere. A considerable asymmetry of proton fluxes is detected. A considerable effect on the SCR space-and-time characteristics is produced by a large-scale interplanetary magnetic field. To study SCR spectral distributions, data are considered on proton fluxes within energy ranges from 5 to 90 MeV (''Meteor'' satellite) and from 10 to 60 MeV (''Explorer'' satellite). The spectra are approximated by the power law. Results of investigations have shown that there is connection between the SCR space-and-time and spectral characteristics and the direction and structure of the solar magnetic fields, the interplanetary space and the geomagnetic field

  15. The effect of target properties on transient crater scaling for simple craters

    Science.gov (United States)

    Prieur, N. C.; Rolf, T.; Luther, R.; Wünnemann, K.; Xiao, Z.; Werner, S. C.

    2017-08-01

    The effects of the coefficient of friction and porosity on impact cratering are not sufficiently considered in scaling laws that predict the crater size from a known impactor size, velocity, and mass. We carried out a systematic numerical study employing more than 1000 two-dimensional models of simple crater formation under lunar conditions in targets with varying properties. A simple numerical setup is used where targets are approximated as granular or brecciated materials, and any compression of porous materials results in permanent compaction. The results are found to be consistent with impact laboratory experiments for water, low-strength and low-porosity materials (e.g., wet sand), and sands. Using this assumption, we found that both the friction coefficient and porosity are important for estimating transient crater diameters as is the strength term in crater scaling laws, i.e., the effective strength. The effects of porosity and friction coefficient on impact cratering were parameterized and incorporated into π group scaling laws, and predict transient crater diameters within an accuracy of ±5% for targets with friction coefficients f ≥ 0.4 and porosities Φ = 0-30%. Moreover, 90 crater scaling relationships are made available and can be used to estimate transient crater diameters on various terrains and geological units with different coefficient of friction, porosity, and cohesion. The derived relationships are most robust for targets with Φ > 10-15%, applicable for a lunar environment, and could therefore yield significant insights into the influence of target properties on cratering statistics.

  16. Evidence for rapid topographic evolution and crater degradation on Mercury from simple crater morphometry

    Science.gov (United States)

    Fassett, Caleb I.; Crowley, Malinda C.; Leight, Clarissa; Dyar, M. Darby; Minton, David A.; Hirabayashi, Masatoshi; Thomson, Bradley J.; Watters, Wesley A.

    2017-06-01

    Examining the topography of impact craters and their evolution with time is useful for assessing how fast planetary surfaces evolve. Here, new measurements of depth/diameter (d/D) ratios for 204 craters of 2.5 to 5 km in diameter superposed on Mercury's smooth plains are reported. The median d/D is 0.13, much lower than expected for newly formed simple craters ( 0.21). In comparison, lunar craters that postdate the maria are much less modified, and the median crater in the same size range has a d/D ratio that is nearly indistinguishable from the fresh value. This difference in crater degradation is remarkable given that Mercury's smooth plains and the lunar maria likely have ages that are comparable, if not identical. Applying a topographic diffusion model, these results imply that crater degradation is faster by a factor of approximately two on Mercury than on the Moon, suggesting more rapid landform evolution on Mercury at all scales.Plain Language SummaryMercury and the Moon are both airless bodies that have experienced numerous impact events over billions of years. These impacts form craters in a geologic instant. The question examined in this manuscript is how fast these craters erode after their formation. To simplify the problem, we examined craters of a particular size (2.5 to 5 km in diameter) on a particular geologic terrain type (volcanic smooth plains) on both the Moon and Mercury. We then measured the topography of hundreds of craters on both bodies that met these criteria. Our results suggest that craters on Mercury become shallower much more quickly than craters on the Moon. We estimate that Mercury's topography erodes at a rate at least a factor of two faster than the Moon's.

  17. Spectral, Photometric, and Dynamic Analysis of Eight Draconid Meteors

    Czech Academy of Sciences Publication Activity Database

    Borovička, Jiří; Koten, Pavel; Shrbený, Lukáš; Štork, Rostislav; Hornoch, Kamil

    2014-01-01

    Roč. 113, 1-4 (2014), s. 15-31 ISSN 0167-9295 R&D Projects: GA ČR(CZ) GAP209/11/1382; GA ČR GPP209/11/P651; GA ČR GA205/09/1302 Institutional support: RVO:67985815 Keywords : meteors * meteoroids * Draconids Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 0.667, year: 2014

  18. 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

  19. Various meteor scenes III: Recurrent showers and some minor showers

    Science.gov (United States)

    Koseki, Masahiro

    2015-02-01

    Meteor activities vary widely from year to year. We study here the June Bootids (JBO), τ-Herculids (TAH), and Andromedids (AND) which are basic examples for the recurrent nature of meteor showers. Half a century has passed since well-known photographic or radar meteor showers were detected. It is necessary to note that some `established' IAU showers are historical ones and we cannot always see them. We find the historical trace of AND by video and four distinct activities in the area of JBC (=JBO+TAH). Meteor showers look different by different observational techniques. Many minor showers in the IAU list have been detected only by observations stored for many days and many years; visual observations in a single night cannot perceive them naturally. We studied the φ-Piscids (PPS), χ-Taurids (CTA), γ-Ursae Minorids (GUM), η-Pegasids (ETP), and α-Sextantids (ASX) as examples and found they have not been recognized by visual observers at all. It is noteworthy that some of them have possible identifications in the IAU list and in preceding observations or reports. The difference in search methods makes the situations much more complicated. The five minor showers we studied here do not have confirmations by all observational techniques. Geobased search (radiant point, time of the observation, and possibly geocentric velocity) may overlook showers which are dispersed in radiant position. A search using the D-criterion is dependent on the presumption of a spherical distribution in the orbital space and may not represent the real distribution, or may overestimate the accuracy of the observations and lead to subdividing the showers into several parts. We must use these search methods properly.

  20. 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.

  1. Advanced Meteor radar at Tirupati: System details and first results

    Science.gov (United States)

    Sunkara, Eswaraiah; Gurubaran, Subramanian; Sundararaman, Sathishkumar; Venkat Ratnam, Madineni; Karanam, Kishore Kumar; Eethamakula, Kosalendra; Vijaya Bhaskara Rao, S.

    An advanced meteor radar viz., Enhanced Meteor Detection Radar (EMDR) operating at 35.25 MHz is installed at Sri Venkateswara University (SVU), Tirupati (13.63oN, 79.4oE), India, in the month of August 2013. Present communication describes the need for the meteor radar at present location, system description, its measurement techniques, its variables and comparison of measured mean winds with contemporary radars over the Indian region. The present radar site is selected to fill the blind region of Gadanki (13.5oN, 79.2oE) MST radar, which covers mesosphere and lower thermosphere (MLT) region (70-110 km). By modifying the receiving antenna structure and elements, this radar is capable of providing accurate wind information between 70 and 110 km unlike other similar radars. Height covering region is extended by increasing the meteor counting capacity by modifying the receiving antenna structure and elements and hence its wind estimation limits extended below and above of 80 and 100 km, respectively. In the present study, we also made comparison of horizontal winds in the MLT region with those measured by similar and different (MST and MF radars) techniques over the Indian region including the model (HWM 07) data sets. The comparison showed a very good agreement between the overlapping altitudes (82-98 km) of different radars. Zonal winds compared very well as that of meridional winds. The observed discrepancies and limitations in the wind measurement are discussed. This new radar is expected to play important role in understanding the vertical and lateral coupling by forming a unique local network.

  2. Improvement of software for analysis of visual meteor data

    Science.gov (United States)

    Veljković, K.; Ivanović, I.

    2015-01-01

    In this paper, we present improvements made on our software for the analysis of visual meteor data. R package MetFns received major updates. Selection filters and algorithms for calculation of zenithal hourly rate and population index, as well as accompanying graphics, are corrected and their performance is improved. Web application MetRApp contains a completely remade user interface and some new features. Also, calculation performances are optimized.

  3. Small Craters and Their Diagnostic Potential

    Science.gov (United States)

    Bugiolacchi, R.

    2017-07-01

    I analysed and compared the size-frequency distributions of craters in the Apollo 17 landing region, comprising of six mare terrains with varying morphologies and cratering characteristics, along with three other regions allegedly affected by the same secondary event (Tycho secondary surge). I propose that for the smaller crater sizes (in this work 9-30 m), a] an exponential curve of power -0.18D can approximate Nkm-2 crater densities in a regime of equilibrium, while b] a power function D-3 closely describes the factorised representation of craters by size (1 m). The saturation level within the Central Area suggests that c] either the modelled rates of crater erosion on the Moon should be revised, or that the Tycho event occurred much earlier in time than the current estimate. We propose that d] the size-frequency distribution of small secondary craters may bear the signature (in terms of size-frequency distribution of debris/surge) of the source impact and that this observation should be tested further.

  4. Processing Images of Craters for Spacecraft Navigation

    Science.gov (United States)

    Cheng, Yang; Johnson, Andrew E.; Matthies, Larry H.

    2009-01-01

    A crater-detection algorithm has been conceived to enable automation of what, heretofore, have been manual processes for utilizing images of craters on a celestial body as landmarks for navigating a spacecraft flying near or landing on that body. The images are acquired by an electronic camera aboard the spacecraft, then digitized, then processed by the algorithm, which consists mainly of the following steps: 1. Edges in an image detected and placed in a database. 2. Crater rim edges are selected from the edge database. 3. Edges that belong to the same crater are grouped together. 4. An ellipse is fitted to each group of crater edges. 5. Ellipses are refined directly in the image domain to reduce errors introduced in the detection of edges and fitting of ellipses. 6. The quality of each detected crater is evaluated. It is planned to utilize this algorithm as the basis of a computer program for automated, real-time, onboard processing of crater-image data. Experimental studies have led to the conclusion that this algorithm is capable of a detection rate >93 percent, a false-alarm rate <5 percent, a geometric error <0.5 pixel, and a position error <0.3 pixel.

  5. Radon progeny in hydro-meteors at the earth's surface

    International Nuclear Information System (INIS)

    Voltaggio, M.

    2008-01-01

    During atmospheric thermal inversions, dew and hoarfrost concentrate gamma emitting radionuclides of the short-lived 222 Rn progeny ( 214 Pb and 214 Bi), causing an increase in the total natural gamma background from the ground. To highlight this phenomenon, a volcanic zone of high 222 Rn flux was studied during the winter season 2010-11. High-specific short-lived radon progeny activities up to 122 Bq g -1 were detected in hydro-meteors forming at the earth's surface (ESHs), corresponding to a mean increase of up to 17 % of the normal gamma background value. A theoretical model, depending on radon flux from soil and predicting the radon progeny concentrations in hydro-meteors forming at the ESHs is presented. The comparison between model and field data shows a good correspondence. Around nuclear power plants or in nuclear facilities that use automatic NaI or CsI total gamma spectroscopy systems for monitoring radioactive contamination, hydro-meteors forming at the ESHs in sites with a high radon flux could represent a relevant source of false alarms of radioactive contamination. (authors)

  6. 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.

  7. Sands at Gusev Crater, Mars

    Science.gov (United States)

    Cabrol, Nathalie A.; Herkenhoff, Kenneth E.; Knoll, Andrew H.; Farmer, Jack D.; Arvidson, Raymond E.; Grin, E.A.; Li, Ron; Fenton, Lori; Cohen, B.; Bell, J.F.; Yingst, R. Aileen

    2014-01-01

    Processes, environments, and the energy associated with the transport and deposition of sand at Gusev Crater are characterized at the microscopic scale through the comparison of statistical moments for particle size and shape distributions. Bivariate and factor analyses define distinct textural groups at 51 sites along the traverse completed by the Spirit rover as it crossed the plains and went into the Columbia Hills. Fine-to-medium sand is ubiquitous in ripples and wind drifts. Most distributions show excess fine material, consistent with a predominance of wind erosion over the last 3.8 billion years. Negative skewness at West Valley is explained by the removal of fine sand during active erosion, or alternatively, by excess accumulation of coarse sand from a local source. The coarse to very coarse sand particles of ripple armors in the basaltic plains have a unique combination of size and shape. Their distribution display significant changes in their statistical moments within the ~400 m that separate the Columbia Memorial Station from Bonneville Crater. Results are consistent with aeolian and/or impact deposition, while the elongated and rounded shape of the grains forming the ripples, as well as their direction of origin, could point to Ma'adim Vallis as a possible source. For smaller particles on the traverse, our findings confirm that aeolian processes have dominated over impact and other processes to produce sands with the observed size and shape patterns across a spectrum of geologic (e.g., ripples and plains soils) and aerographic settings (e.g., wind shadows).

  8. Locating the LCROSS Impact Craters

    Science.gov (United States)

    Marshall, William; Shirley, Mark; Moratto, Zachary; Colaprete, Anthony; Neumann, Gregory A.; Smith, David E.; Hensley, Scott; Wilson, Barbara; Slade, Martin; Kennedy, Brian; hide

    2012-01-01

    The Lunar CRater Observations and Sensing Satellite (LCROSS) mission impacted a spent Centaur rocket stage into a permanently shadowed region near the lunar south pole. The Sheperding Spacecraft (SSC) separated approx. 9 hours before impact and performed a small braking maneuver in order to observe the Centaur impact plume, looking for evidence of water and other volatiles, before impacting itself. This paper describes the registration of imagery of the LCROSS impact region from the mid- and near-infrared cameras onboard the SSC, as well as from the Goldstone radar. We compare the Centaur impact features, positively identified in the first two, and with a consistent feature in the third, which are interpreted as a 20 m diameter crater surrounded by a 160 m diameter ejecta region. The images are registered to Lunar Reconnaisance Orbiter (LRO) topographical data which allows determination of the impact location. This location is compared with the impact location derived from ground-based tracking and propagation of the spacecraft's trajectory and with locations derived from two hybrid imagery/trajectory methods. The four methods give a weighted average Centaur impact location of -84.6796 deg, -48.7093 deg, with a 1s uncertainty of 115 m along latitude, and 44 m along longitude, just 146 m from the target impact site. Meanwhile, the trajectory-derived SSC impact location is -84.719 deg, -49.61 deg, with a 1 alpha uncertainty of 3 m along the Earth vector and 75 m orthogonal to that, 766 m from the target location and 2.803 km south-west of the Centaur impact. We also detail the Centaur impact angle and SSC instrument pointing errors. Six high-level LCROSS mission requirements are shown to be met by wide margins. We hope that these results facilitate further analyses of the LCROSS experiment data and follow-up observations of the impact region

  9. Cratering Rates in the Jovian System

    Science.gov (United States)

    Zahnle, K.; Dons, L.; Levison, H.

    2004-01-01

    We use several independent constraints on the number of ecliptic comets to estimate impact cratering rates on the Jupiter moons. The impact rate on Jupiter by 1.5-km diameter ecliptic comets is currently NY(d > 1.5km) = 0.005(+0.006)(-0.003) per annum. Asteroids and long period comets are currently unimportant. The size-number distribution of ecliptic comets smaller than 20 km is inferred from size-number distributions of impact craters on Europa, Ganymede, and Triton. For comets bigger than 50 km we use the size-number distribution of Kuiper Belt Objects. The overview of the impact rate at Jupiter in general and at Europa in particular are given. These impact rates imply cratering rates on Europa of 0.5 per Ma per 10(exp 6) sq km for impact craters bigger than 1 km, and of 0.015 per Ma per 10(exp 6) sq km for impact craters bigger than 20 km. The latter corresponds to an average recurrence time of 2.2 Ma for 20 km craters. The best current estimates for the number of 20 km craters on Europa appear to range between about twelve to thirty. This implies that the average age of Europa's surface is between 30 and 70 Ma. The average density of craters with diameter greater than 1 km on well-mapped swaths on Europa is 30 per 10(exp 6) sq km. The corresponding nominal surface age would be 60 Ma. These two estimates are not truly independent because we have used size-number distribution of the Europan craters to help generate the size-number distribution of comets. The uncertainty of the best estimate - call it 42 Ma for specificity - is at least a factor of 3.

  10. Craters of the Pluto-Charon System

    Science.gov (United States)

    Robbins, Stuart J.; Singer, Kelsi N.; Bray, Veronica J.; Schenk, Paul; Lauer, Todd R.; Weaver, Harold A.; Runyon, Kirby; Mckinnon, William B.; Beyer, Ross A.; Porter, Simon; hide

    2016-01-01

    NASA's New Horizons flyby mission of the Pluto-Charon binary system and its four moons provided humanity with its first spacecraft-based look at a large Kuiper Belt Object beyond Triton. Excluding this system, multiple Kuiper Belt Objects (KBOs) have been observed for only 20 years from Earth, and the KBO size distribution is unconstrained except among the largest objects. Because small KBOs will remain beyond the capabilities of ground-based observatories for the foreseeable future, one of the best ways to constrain the small KBO population is to examine the craters they have made on the Pluto-Charon system. The first step to understanding the crater population is to map it. In this work, we describe the steps undertaken to produce a robust crater database of impact features on Pluto, Charon, and their two largest moons, Nix and Hydra. These include an examination of different types of images and image processing, and we present an analysis of variability among the crater mapping team, where crater diameters were found to average +/-10% uncertainty across all sizes measured (approx.0.5-300 km). We also present a few basic analyses of the crater databases, finding that Pluto's craters' differential size-frequency distribution across the encounter hemisphere has a power-law slope of approximately -3.1 +/- 0.1 over diameters D approx. = 15-200 km, and Charon's has a slope of -3.0 +/- 0.2 over diameters D approx. = 10-120 km; it is significantly shallower on both bodies at smaller diameters. We also better quantify evidence of resurfacing evidenced by Pluto's craters in contrast with Charon's. With this work, we are also releasing our database of potential and probable impact craters: 5287 on Pluto, 2287 on Charon, 35 on Nix, and 6 on Hydra.

  11. Ceres and the terrestrial planets impact cratering record

    Science.gov (United States)

    Strom, R. G.; Marchi, S.; Malhotra, R.

    2018-03-01

    Dwarf planet Ceres, the largest object in the Main Asteroid Belt, has a surface that exhibits a range of crater densities for a crater diameter range of 5-300 km. In all areas the shape of the craters' size-frequency distribution is very similar to those of the most ancient heavily cratered surfaces on the terrestrial planets. The most heavily cratered terrain on Ceres covers ∼15% of its surface and has a crater density similar to the highest crater density on population whose size-frequency distribution resembles that of the Main Belt Asteroids.

  12. Meteor observations with Mini-Mega-TORTORA wide-field monitoring system

    Science.gov (United States)

    Karpov, S.; Orekhova, N.; Beskin, G.; Biryukov, A.; Bondar, S.; Ivanov, E.; Katkova, E.; Perkov, A.; Sasyuk, V.

    2016-12-01

    Here we report on the results of meteor observations with 9-channel Mini-Mega-TORTORA (MMT-9) optical monitoring system with the wide field and high temporal resolution. During the first 1.5 years of operation more than 90 thousands of meteors have been detected, at a rate of 300-350 per night, with durations from 0.1 to 2.5 seconds and angular velocities up to 38 degrees per second. The faintest detected meteors have peak brightnesses about 10 mag, while the majority have them ranging from 4 to 8 mag. Some of the meteors have been observed in BVR filters simultaneously. Color variations along the trail for them have been determined. The parameters of the detected meteors have been published online. The database also includes data from 10 thousands of meteors detected by our previous FAVOR camera during 2006-2009.

  13. Modelling a short-wake meteor as a single or fragmenting body

    Science.gov (United States)

    Campbell-Brown, M.

    2017-09-01

    An attempt is made to model a meteor observed with the Canadian Automated Meteor Observatory tracking system using a single body model. This meteor showed only very faint wake, implying that fragmentation was not important. Previous attempts to model the meteor with models of fragmenting meteors had overpredicted the amount of wake seen. A single-body, non-homogeneous ablation code was developed, but proved unsuccessful at matching the observed light curve of the meteor, even after a thorough search of parameter space. A model of a meteoroid fragmenting in many small bursts of small fragments was developed in an attempt to match both the light curve and the observed wake, and it succeeded in producing a qualitative fit to the light curve and to the high-resolution wake.

  14. Long-Term Continuous Double Station Observation of Faint Meteor Showers.

    Science.gov (United States)

    Vítek, Stanislav; Páta, Petr; Koten, Pavel; Fliegel, Karel

    2016-09-14

    Meteor detection and analysis is an essential topic in the field of astronomy. In this paper, a high-sensitivity and high-time-resolution imaging device for the detection of faint meteoric events is presented. The instrument is based on a fast CCD camera and an image intensifier. Two such instruments form a double-station observation network. The MAIA (Meteor Automatic Imager and Analyzer) system has been in continuous operation since 2013 and has successfully captured hundreds of meteors belonging to different meteor showers, as well as sporadic meteors. A data processing pipeline for the efficient processing and evaluation of the massive amount of video sequences is also introduced in this paper.

  15. Instrument for the detection of meteors in the infrared

    Science.gov (United States)

    Svedhem, H.; Koschny, D.; Ter Haar, J.

    2014-07-01

    The flux of interplanetary particles in the size range 2 mm to 20 m is poorly constrained due to insufficient data --- the larger bodies may be observed remotely by ground-based or space-based telescopes and the smaller particles are measured by in-situ impact detectors in space or by meteor cameras from ground. An infrared video rate imager in Earth orbit would enable a systematic characterization for an extended period, day and night, of the flux in this range by monitoring the bright meteor/fireball generated during atmospheric entry. Due to the low flux of meteoroids in this range a very large detector is required. With this method a large portion of the Earth atmosphere is in fact used as a huge detector. Such an instrument has never flown in Earth orbit. The only sensors of a similar kind fly on US defense satellites for monitoring launches of ballistic missiles. The data from these sensors, however, is largely inaccessible to scientists. The knowledge on emission of light by meteors/bolides at infrared wavelengths is very limited while it can be suspected that the continuum emission from meteors/bolides have stronger emission at infrared wavelengths than in the visible due to the likely low temperatures of these events. At the same time line emission is dominating over the continuum in the visible so it is not clear how this will compare with the continuum in the infrared. We have developed a bread-board version of an IR video rate camera, the SPOSH-IR. The instrument is based on an earlier technology development, SPOSH --- Smart Panoramic Optical Sensor Head, for operation in the visible range, but with the sensor replaced by a cooled IR detector and new infrared optics. The earlier work has proven the concept of the instrument and of automatic detection of meteors/bolides in the visible wavelength range. The new hardware has been built by Jena-Optronik, Jena, Germany and has been tested during several meteor showers in the Netherlands and at ESA's OGS

  16. The effects of the Chesapeake Bay impact crater on the geologic framework and the correlation of hydrogeologic units of southeastern Virginia, south of the James River

    Science.gov (United States)

    Powars, David S.

    2000-01-01

    About 35 million years ago, a large comet or meteor slammed into the shallow shelf on the western margin of the Atlantic Ocean, creating the Chesapeake Bay impact crater. This report, the second in a series, refines the geologic framework of southeastern Virginia, south of the James River in and near the impact crater, and presents evidence for the existence of a pre-impact James River structural zone. The report includes detailed correlations of core lithologies with borehole geophysical logs; the correlations provide the foundation for the compilation of stratigraphic cross sections. These cross sections are tied into the geologic framework of the lower York-James Peninsula as presented in the first report in the series, Professional Paper 1612

  17. Detection and Characterisation of Meteors as a Big Data Citizen Science project

    Science.gov (United States)

    Gritsevich, M.

    2017-12-01

    Out of a total around 50,000 meteorites currently known to science, the atmospheric passage was recorded instrumentally in only 30 cases with the potential to derive their atmospheric trajectories and pre-impact heliocentric orbits. Similarly, while the observations of meteors, add thousands of new entries per month to existing databases, it is extremely rare they lead to meteorite recovery. Meteor studies thus represent an excellent example of the Big Data citizen science project, where progress in the field largely depends on the prompt identification and characterisation of meteor events as well as on extensive and valuable contributions by amateur observers. Over the last couple of decades technological advancements in observational techniques have yielded drastic improvements in the quality, quantity and diversity of meteor data, while even more ambitious instruments are about to become operational. This empowers meteor science to boost its experimental and theoretical horizons and seek more advanced scientific goals. We review some of the developments that push meteor science into the Big Data era that requires more complex methodological approaches through interdisciplinary collaborations with other branches of physics and computer science. We argue that meteor science should become an integral part of large surveys in astronomy, aeronomy and space physics, and tackle the complexity of micro-physics of meteor plasma and its interaction with the atmosphere. The recent increased interest in meteor science triggered by the Chelyabinsk fireball helps in building the case for technologically and logistically more ambitious meteor projects. This requires developing new methodological approaches in meteor research, with Big Data science and close collaboration between citizen science, geoscience and astronomy as critical elements. We discuss possibilities for improvements and promote an opportunity for collaboration in meteor science within the currently

  18. On the Clustering of Europa's Small Craters

    Science.gov (United States)

    Bierhaus, E. B.; Chapman, C. R.; Merline, W. J.

    2001-01-01

    We analyze the spatial distribution of Europa's small craters and find that many are too tightly clustered to result from random, primary impacts. Additional information is contained in the original extended abstract.

  19. Latitude Variation for Pluto's Crater Distribution

    Science.gov (United States)

    Dwivedi, A. K.; Binzel, R. P.; Earle, A. M.; Singer, K. N.; Stern, A.; Olkin, C.; Weaver, H. A., Jr.; Ennico Smith, K.; Young, L. A.

    2017-12-01

    The crater population distribution on Pluto and Charon have been studied to infer the size distribution of objects in the Kuiper belt (Singer et al. 2017; submitted). In this talk, we will look at the variation in crater distribution with latitude. To circumvent possible bias effects in the analysis, we focus our analysis on a region having the most consistent imaging resolution afforded by the flyby geometry. The longitudinal extent of our study region is 90E to 150E, and the latitudinal extent is 0°N to 90°N. Our preliminary analysis shows crater population peaks in the latitude range 30°N to 60°N and drops off sharply toward the north pole. Here we describe how we quantify the crater distribution in this region and explore a range of processes for volatile transport over both orbital timescales and perihelion precession timescales, including million year Milankovitch cycles for obliquity oscillations.

  20. Topography of the Martian Impact Crater Tooting

    Science.gov (United States)

    Mouginis-Mark, P. J.; Garbeil, H.; Boyce, J. M.

    2009-01-01

    Tooting crater is approx.29 km in diameter, is located at 23.4degN, 207.5degE, and is classified as a multi-layered ejecta crater [1]. Our mapping last year identified several challenges that can now be addressed with HiRISE and CTX images, but specifically the third dimension of units. To address the distribution of ponded sediments, lobate flows, and volatile-bearing units within the crater cavity, we have focused this year on creating digital elevation models (DEMs) for the crater and ejecta blanket from stereo CTX and HiRISE images. These DEMs have a spatial resolution of approx.50 m for CTX data, and 2 m for HiRISE data. Each DEM is referenced to all of the available individual MOLA data points within an image, which number approx.5,000 and 800 respectively for the two data types

  1. Meteor matter interaction with the Earth's atmosphere and the ionospheric E-region structure

    International Nuclear Information System (INIS)

    Alimov, O.

    1987-01-01

    The exploration of the ionospheric E region is a pressing problem, both in the applied and fundamental studies. Results are presented of an investigation: (1) to estimate the meteor ionization contribution to the night time E layer and influx; (2) to study the phenomenon of intensive sporadic layer formation following cessation of meteor stream activity; and (3) to access the role of metallic ions of meteor origin in the diurnal and seasonal variations in the occurrence probabilities of midlatitude E/sub s/. The contribution was evaluated of meteor matter, Lyman radiation and corpuscular particles to the electron concentration of the night E region. Results are discussed

  2. Crater Mound Formation by Wind Erosion on Mars

    Science.gov (United States)

    Steele, L. J.; Kite, E. S.; Michaels, T. I.

    2018-01-01

    Most of Mars' ancient sedimentary rocks by volume are in wind-eroded sedimentary mounds within impact craters and canyons, but the connections between mound form and wind erosion are unclear. We perform mesoscale simulations of different crater and mound morphologies to understand the formation of sedimentary mounds. As crater depth increases, slope winds produce increased erosion near the base of the crater wall, forming mounds. Peak erosion rates occur when the crater depth is ˜2 km. Mound evolution depends on the size of the host crater. In smaller craters mounds preferentially erode at the top, becoming more squat, while in larger craters mounds become steeper sided. This agrees with observations where smaller craters tend to have proportionally shorter mounds and larger craters have mounds encircled by moats. If a large-scale sedimentary layer blankets a crater, then as the layer recedes across the crater it will erode more toward the edges of the crater, resulting in a crescent-shaped moat. When a 160 km diameter mound-hosting crater is subject to a prevailing wind, the surface wind stress is stronger on the leeward side than on the windward side. This results in the center of the mound appearing to "march upwind" over time and forming a "bat-wing" shape, as is observed for Mount Sharp in Gale crater.

  3. METEOR v1.0 - Design and structure of the software package; METEOR v1.0 - Estructura y modulos informaticos

    Energy Technology Data Exchange (ETDEWEB)

    Palomo, E.

    1994-07-01

    This script describes the structure and the separated modules of the software package METEOR for the statistical analysis of meteorological data series. It contains a systematic description of the subroutines of METEOR and, also, of the required shape for input and output files. 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 thc 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 v 1.0: Design and structure of the software package. (Author)

  4. Nuclear cratering on a digital computer

    International Nuclear Information System (INIS)

    Terhune, R.W.; Stubbs, T.F.; Cherry, J.T.

    1970-01-01

    Computer programs based on the artificial viscosity method are applied to developing an understanding of the physics of cratering, with emphasis on cratering by nuclear explosives. Two established codes, SOC (spherical symmetry) and TENSOR (cylindrical symmetry), are used to illustrate the effects of variations in the material properties of various media on the cratering processes, namely shock, spall, and gas acceleration. Water content is found to be the most important material property, followed by strength, porosity, and compressibility. Crater profile calculations are presented for Pre-Gondola Charley (20-ton nitromethane detonation in shale) and Sedan (100-kt nuclear detonation in alluvium). Calculations also are presented for three 1-Mt yields in saturated Divide basalt and 1-Mt yield in dry Buckboard basalt, to show crater geometry as a function of the burial depth for large explosive yields. The calculations show, for megaton-level yields, that gas acceleration is the dominate mechanism in determining crater size and depends in turn on the water content in the medium. (author)

  5. Sand Dunes in Kaiser Crater

    Science.gov (United States)

    2002-01-01

    Full size (780 KBytes) This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) high resolution image shows a field of dark sand dunes on the floor of Kaiser Crater in southeastern Noachis Terra. The steepest slopes on each dune, the slip faces, point toward the east, indicating that the strongest winds that blow across the floor of Kaiser move sand in this direction. Wind features of three different scales are visible in this image: the largest (the dunes) are moving across a hard surface (light tone) that is itself partially covered by large ripples. These large ripples appear not to be moving--the dunes are burying some and revealing others. Another type of ripple pattern is seen on the margins of the dunes and where dunes coalesce. They are smaller (both in their height and in their separation) than the large ripples. These are probably coarse sediments that are moving with the dunes. This picture covers an area approximately 3 km (1.9 mi) across and is illuminated from the upper left.

  6. Kinematic Characteristics of Meteor Showers by Results of the Combined Radio-Television Observations

    Science.gov (United States)

    Narziev, Mirhusen

    2016-07-01

    One of the most important tasks of meteor astronomy is the study of the distribution of meteoroid matter in the solar system. The most important component to address this issue presents the results of measurements of the velocities, radiants, and orbits of both showers and sporadic meteors. Radiant's and orbits of meteors for different sets of data obtained as a result of photographic, television, electro-optical, video, Fireball Network and radar observations have been measured repeatedly. However, radiants, velocities and orbits of shower meteors based on the results of combined radar-optical observations have not been sufficiently studied. In this paper, we present a methods for computing the radiants, velocities, and orbits of the combined radar-TV meteor observations carried out at HisAO in 1978-1980. As a result of the two-year cycle of simultaneous TV-radar observations 57 simultaneous meteors have been identified. Analysis of the TV images has shown that some meteor trails appeared as dashed lines. Among the simultaneous meteors of d-Aquariids 10 produced such dashed images, and among the Perseids there were only 7. Using a known method, for such fragmented images of simultaneous meteors - together with the measured radar distance, trace length, and time interval between the segments - allowed to determine meteor velocity using combined method. In addition, velocity of the same meteors was measured using diffraction and radar range-time methods based on the results of radar observation. It has been determined that the mean values of meteoroid velocity based on the combined radar-TV observations are greater in 1 ÷ 3 km / c than the averaged velocity values measured using only radar methods. Orbits of the simultaneously observed meteors with segmented photographic images were calculated on the basis of the average velocity observed using the combined radar-TV method. The measured results of radiants velocities and orbital elements of individual meteors

  7. Knut Lundmark, meteors and an early Swedish crowdsourcing experiment.

    Science.gov (United States)

    Kärnfelt, Johan

    2014-10-01

    Mid twentieth century meteor astronomy demanded the long-term compilation of observations made by numerous individuals over an extensive geographical area. Such a massive undertaking obviously required the participation of more than just professional astronomers, who often sought to expand their ranks through the use of amateurs that had a basic grasp of astronomy as well as the night sky, and were thus capable of generating first-rate astronomical reports. When, in the 1920s, renowned Swedish astronomer Knut Lundmark turned his attention to meteor astronomy, he was unable to rely even upon this solution. In contrast to many other countries at the time, Sweden lacked an organized amateur astronomy and thus contained only a handful of competent amateurs. Given this situation, Lundmark had to develop ways of engaging the general public in assisting his efforts. To his advantage, he was already a well-established public figure who had published numerous popular science articles and held talks from time to time on the radio. During the 1930s, this prominence greatly facilitated his launching of a crowdsourcing initiative for the gathering of meteor observations. This paper consists of a detailed discussion concerning the means by which Lundmark's initiative disseminated astronomical knowledge to the general public and encouraged a response that might directly contribute to the advancement of science. More precisely, the article explores the manner in which he approached the Swedish public, the degree to which that public responded and the extent to which his efforts were successful. The primary aim of this exercise is to show that the apparently recent Internet phenomenon of 'crowdsourcing', especially as it relates to scientific research, actually has a pre-Internet history that is worth studying. Apart from the fact that this history is interesting in its own right, knowing it can provide us with a fresh vantage point from which to better comprehend and appreciate

  8. Origin of fumarolic fluids from Tupungatito Volcano (Central Chile): interplay between magmatic, hydrothermal, and shallow meteoric sources

    Science.gov (United States)

    Benavente, Oscar; Tassi, Franco; Gutiérrez, Francisco; Vaselli, Orlando; Aguilera, Felipe; Reich, Martin

    2013-08-01

    Tupungatito is a poorly known volcano located about 100 km eastward of Santiago (Chile) in the northernmost sector of the South Volcanic Zone. This 5,682 m high volcano shows intense fumarolic activity. It hosts three crater lakes within the northwestern portion of the summit area. Chemical compositions of fumarolic gases and isotopic signatures of noble gases (3He/4He and 40Ar/36Ar are up to 6.09 Ra and 461, respectively), and steam (δ18O and δD) suggest that they are produced by mixing of fluids from a magmatic source rich in acidic gas compounds (SO2, HCl, and HF), and meteoric water. The magmatic-hydrothermal fluids are affected by steam condensation that controls the outlet fumarolic temperatures (contamination from the subducting slab, (2) the sedimentary basement, and (3) limited contribution from crustal sediments. Gas geothermometry based on the kinetically rapid H2-CO equilibria indicates equilibrium temperatures 200 °C and redox conditions are consistent with those inferred by the presence of the SO2-H2S redox pair, typical of fluids that have attained equilibrium in magmatic environment. A comprehensive conceptual geochemical model describing the circulation pattern of the Tupungatito hydrothermal-magmatic fluids is proposed. It includes fluid source regions and re-equilibration processes affecting the different gas species due to changing chemical-physical conditions as the magmatic-hydrothermal fluids rise up toward the surface.

  9. Active methylotrophs in the sediments of Lonar Lake, a saline and alkaline ecosystem formed by meteor impact.

    Science.gov (United States)

    Antony, Chakkiath Paul; Kumaresan, Deepak; Ferrando, Lucia; Boden, Rich; Moussard, Hélène; Scavino, Ana Fernández; Shouche, Yogesh S; Murrell, J Colin

    2010-11-01

    Lonar Lake is a unique saline and alkaline ecosystem formed by meteor impact in the Deccan basalts in India around 52,000 years ago. To investigate the role of methylotrophy in the cycling of carbon in this unusual environment, stable-isotope probing (SIP) was carried out using the one-carbon compounds methane, methanol and methylamine. Denaturing gradient gel electrophoresis fingerprinting analyses performed with heavy (13)C-labelled DNA retrieved from sediment microcosms confirmed the enrichment and labelling of active methylotrophic communities. Clone libraries were constructed using PCR primers targeting 16S rRNA genes and functional genes. Methylomicrobium, Methylophaga and Bacillus spp. were identified as the predominant active methylotrophs in methane, methanol and methylamine SIP microcosms, respectively. Absence of mauA gene amplification in the methylamine SIP heavy fraction also indicated that methylamine metabolism in Lonar Lake sediments may not be mediated by the methylamine dehydrogenase enzyme pathway. Many gene sequences retrieved in this study were not affiliated with extant methanotrophs or methylotrophs. These sequences may represent hitherto uncharacterized novel methylotrophs or heterotrophic organisms that may have been cross-feeding on methylotrophic metabolites or biomass. This study represents an essential first step towards understanding the relevance of methylotrophy in the soda lake sediments of an unusual impact crater structure.

  10. Report on radio observation of meteors (Iža, Slovakia)

    Science.gov (United States)

    Dolinský, Peter; Dorotovič, Ivan; Vidovenec, Marian

    2014-02-01

    During the period from 1 to 17 August 2014 meteors were experimentally registered using radio waves. This experiment was conducted in the village of Iža, Slovakia. Its main objective was to test the technical equipment intended for continuous registration of meteor echoes, which will be located in the Slovak Central Observatory in Hurbanovo. These tests are an indirect continuation of previous experiments of observation of meteor showers using the technology available in Hurbanovo at the end of the 20th and the beginning of the 21st century. The device consists of two independent receiver systems. One recorded echoes of the transmitter Graves 143.050 MHz (N47.3480° E5.5151°, France) and the second one recorded echoes of the TV transmitter Lviv 49.739583 MHz (N49.8480° E24.0369°, Ukraine). The apparatus for tracking radio echoes of the transmitter Graves consists of a 9-element Yagi antenna with vertical polarization (oriented with an elevation of 0° at azimuth 270°), the receiver Yaesu VR-5000 in CW mode, and a computer with registration using the program HROFFT v1.0.0f. The second apparatus recording the echoes of the transmitter Lviv consists of a LP (log-periodic) antenna with horizontal polarization (elevation of 0° and azimuth of 90°), the receiver ICOM R-75 in the CW mode, and also a computer with registration using HROFFT v1.0.0f. A total of about 78000 echoes have been registered during around 700 hours of registration. Probably not all of them are caused by meteors. These data were statistically processed and compared with visual observations in the IMO database. Planned own visual observations could not be performed due to unfavourable weather conditions lasting from 4 to 13 August 2014. The registered data suggest that observations were performed in the back-scatter mode in this configuration and not in the planned forward-scatter mode. Deeper analysis and longer data sets are, however, necessary to calibrate the observation system and this will

  11. Automated Meteor Detection by All-Sky Digital Camera Systems

    Czech Academy of Sciences Publication Activity Database

    Suk, Tomáš; Šimberová, Stanislava

    2017-01-01

    Roč. 120, č. 3 (2017), s. 189-215 ISSN 0167-9295 R&D Projects: GA ČR GA15-16928S Institutional support: RVO:67985815 ; RVO:67985556 Keywords : meteor detection * autonomous fireball observatories * fish- eye camera * Hough transformation Subject RIV: IN - Informatics, Computer Science; BN - Astronomy, Celestial Mechanics, Astrophysics (ASU-R) OBOR OECD: Computer sciences, information science, bioinformathics (hardware development to be 2.2, social aspect to be 5.8); Astronomy (including astrophysics,space science) (ASU-R) Impact factor: 0.875, year: 2016

  12. Pancam Peek into 'Victoria Crater' (Stereo)

    Science.gov (United States)

    2006-01-01

    [figure removed for brevity, see original site] Left-eye view of a stereo pair for PIA08776 [figure removed for brevity, see original site] Right-eye view of a stereo pair for PIA08776 A drive of about 60 meters (about 200 feet) on the 943rd Martian day, or sol, of Opportunity's exploration of Mars' Meridiani Planum region (Sept. 18, 2006) brought the NASA rover to within about 50 meters (about 160 feet) of the rim of 'Victoria Crater.' This crater has been the mission's long-term destination for the past 21 Earth months. Opportunity reached a location from which the cameras on top of the rover's mast could begin to see into the interior of Victoria. This stereo anaglyph was made from frames taken on sol 943 by the panoramic camera (Pancam) to offer a three-dimensional view when seen through red-blue glasses. It shows the upper portion of interior crater walls facing toward Opportunity from up to about 850 meters (half a mile) away. The amount of vertical relief visible at the top of the interior walls from this angle is about 15 meters (about 50 feet). The exposures were taken through a Pancam filter selecting wavelengths centered on 750 nanometers. Victoria Crater is about five times wider than 'Endurance Crater,' which Opportunity spent six months examining in 2004, and about 40 times wider than 'Eagle Crater,' where Opportunity first landed. The great lure of Victoria is the expectation that a thick stack of geological layers will be exposed in the crater walls, potentially several times the thickness that was previously studied at Endurance and therefore, potentially preserving several times the historical record.

  13. Radar meteors range distribution model. II. Shower flux density and mass distribution index

    Czech Academy of Sciences Publication Activity Database

    Pecinová, Drahomíra; Pecina, Petr

    2007-01-01

    Roč. 37, č. 2 (2007), s. 107-124 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

  14. Radar meteors range distribution model. III. Ablation, shape-density and self-similarity parameters

    Czech Academy of Sciences Publication Activity Database

    Pecinová, Drahomíra; Pecina, Petr

    2007-01-01

    Roč. 37, č. 3 (2007), s. 147-160 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

  15. Optical observations of enhanced activity of the 2005 Draconid meteor shower

    Czech Academy of Sciences Publication Activity Database

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

    2007-01-01

    Roč. 466, č. 2 (2007), s. 729-735 ISSN 0004-6361 R&D Projects: GA AV ČR KJB300030502; GA ČR GA205/05/0543 Institutional research plan: CEZ:AV0Z10030501 Keywords : meteors * meteor shower s * Draconids Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 4.259, year: 2007

  16. Variations in meteor heights at 22.7°S during solar cycle 23

    Science.gov (United States)

    Lima, L. M.; Araújo, L. R.; Alves, E. O.; Batista, P. P.; Clemesha, B. R.

    2015-10-01

    The meteor radar measurements obtained at Cachoeira Paulista (22.7°S), Brazil, have been used to study a possible relationship between meteor echo height variations and solar flux during solar cycle 23. A good concordance between the normalized values of the annual mean of the meteor peak heights and F10.7 solar radio flux and Mg_II solar indexes have been observed during declining phase of the solar cycle 23. After eliminating the solar activity influence, the annual mean of the meteor echo peak heights showed a linear decrease of 30 m/year when Mg_II solar index is used and 38 m/year when F10.7 solar radio flux is used. When the trend is eliminated the relationship between meteor peak heights and F10.7 solar flux indicate a trend of 672 m/100 sfu (sfu-solar flux unit). The meteor amplitude signals and the decay time drops after mid-2004, which may be attributed to the decreasing of the electron density in the meteor trails. The meteor echo peak height decrease has been interpreted as being caused by a reduction in air density in the upper atmosphere.

  17. PMN-Portuguese Meteor Network and OLA-Observatório do Lago Alqueva agreement

    Science.gov (United States)

    Saraiva, C.

    2018-01-01

    The PMN-Portuguese Meteor Network has two new video meteor detecting systems at OLA- Observartório do Lago Alqueva, situated at the South East Portuguese territory with a pristine night sky and more than 290 clear nights each year.

  18. 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

  19. Determination of the optimal values for the parameters of radio meteors

    International Nuclear Information System (INIS)

    Kostylev, K.K.; Alferova, T.G.

    1985-01-01

    The authors present previously published data from studies of the amplitude time characteristics of the echo signals from underdense meteor trails analyzed by nonlinear optimization logarithms, and they use these results to confirm the hypothesis that small meteor particles experience significant braking in the earth's atmosphere

  20. Complex of techniques for radio-echo studies of meteors in Dushanbe

    International Nuclear Information System (INIS)

    Tshebotaryov, R.P.; Sidorin, V.N.; Polushkin, G.A.; Bibarsov, R.Sh.; Isamutdinov, Sh.O.; Kolmakov, V.M.

    1970-01-01

    A complex of techniques made at the Astrophysical Institute of Academy of Science for the determination of coordinates, heights, radians and velocities of meteors and for research in physics of meteors and upper atmosphere is described. Brief data's on the work of the complex are given

  1. Comparing Eyewitness-Derived Trajectories of Bright Meteors to Ground Truth Data

    Science.gov (United States)

    Moser, D. E.

    2016-01-01

    The NASA Meteoroid Environment Office (MEO) is the only US government agency tasked with analyzing meteors of public interest. When queried about a meteor observed over the United States, the MEO must respond with a characterization of the trajectory, orbit, and size within a few hours. Using observations from meteor networks like the NASA All Sky Fireball Network or the Southern Ontario Meteor Network, such a characterization is often easy. If found, casual recordings from the public and stationary web cameras can be used to roughly analyze a meteor if the camera's location can be identified and its imagery calibrated. This technique was used with great success in the analysis of the Chelyabinsk meteorite fall. But if the event is outside meteor network coverage, if an insufficient number of videos are found, or if the imagery cannot be geolocated or calibrated, a timely assessment can be difficult if not impossible. In this situation, visual reports made by eyewitnesses may be the only resource available. This has led to the development of a tool to quickly calculate crude meteor trajectories from eyewitness reports made to the American Meteor Society. The output is illustrated in Figure 1. A description of the tool, example case studies, and a comparison to ground truth data observed by the NASA All Sky Fireball Network will be presented.

  2. Cratering Equations for Zinc Orthotitanate Coated Aluminum

    Science.gov (United States)

    Hyde, James; Christiansen, Eric; Liou, Jer-Chyi; Ryan, Shannon

    2009-01-01

    The final STS-125 servicing mission (SM4) to the Hubble Space Telescope (HST) in May of 2009 saw the return of the 2nd Wide Field Planetary Camera (WFPC2) aboard the shuttle Discovery. This hardware had been in service on HST since it was installed during the SM1 mission in December of 1993 yielding one of the longest low Earth orbit exposure times (15.4 years) of any returned space hardware. The WFPC2 is equipped with a 0.8 x 2.2 m radiator for thermal control of the camera electronics (Figure 1). The space facing surface of the 4.1 mm thick aluminum radiator is coated with Z93 zinc orthotitanate thermal control paint with a nominal thickness of 0.1 0.2 mm. Post flight inspections of the radiator panel revealed hundreds of micrometeoroid/orbital debris (MMOD) impact craters ranging in size from less than 300 to nearly 1000 microns in diameter. The Z93 paint exhibited large spall areas around the larger impact sites (Figure 2) and the craters observed in the 6061-T651 aluminum had a different shape than those observed in uncoated aluminum. Typical hypervelocity impact craters in aluminum have raised lips around the impact site. The craters in the HST radiator panel had suppressed crater lips, and in some cases multiple craters were present instead of a single individual crater. Humes and Kinard observed similar behavior after the WFPC1 post flight inspection and assumed the Z93 coating was acting like a bumper in a Whipple shield. Similar paint behavior (spall) was also observed by Bland2 during post flight inspection of the International Space Station (ISS) S-Band Antenna Structural Assembly (SASA) in 2008. The SASA, with similar Z93 coated aluminum, was inspected after nearly 4 years of exposure on the ISS. The multi-crater phenomena could be a function of the density, composition, or impact obliquity angle of the impacting particle. For instance, a micrometeoroid particle consisting of loosely bound grains of material could be responsible for creating the

  3. The Crater Ejecta Distribution on Ceres

    Science.gov (United States)

    Schmedemann, Nico; Neesemann, Adrian; Schulzeck, Franziska; Krohn, Katrin; Gathen, Isabel; Otto, Katharina; Jaumann, Ralf; Michael, Gregory; Raymond, Carol; Russell, Christopher

    2017-04-01

    Since March 6 2015 the Dawn spacecraft [1] has been in orbit around the dwarf planet Ceres. At small crater diameters Ceres appears to be peppered with secondary craters that often align in chains or form clusters. Some of such possible crater chains follow curved geometries and are not in a radial orientation with respect to possible source craters [2]. Ceres is a fast rotating body ( 9 h per revolution) with comparatively low surface gravity ( 0.27 m/s2). A substantial fraction of impact ejecta may be launched with velocities similar to Ceres' escape velocity (510 m/s), which implies that many ejected particles follow high and long trajectories. Thus, due to Ceres' fast rotation the distribution pattern of the reimpacting ejected material is heavily affected by Coriolis forces that results in a highly asymmetrical and curved pattern of secondary crater chains. In order to simulate flight trajectories and distribution of impact ejected material for individual craters on Ceres we used the scaling laws by [3] adjusted to the Cerean impact conditions [4] and the impact ejecta model by [5]. These models provide the starting conditions for tracer particles in the simulation. The trajectories of the particles are computed as n-body simulation. The simulation calculates the positions and impact velocities of each impacting tracer particle with respect to the rotating surface of Ceres, which is approximated by a two-axis ellipsoid. Initial results show a number of interesting features in the simulated deposition geometries of specific crater ejecta. These features are roughly in agreement with features that can be observed in Dawn imaging data of the Cerean surface. For example: ray systems of fresh impact craters, non-radial crater chains and global scale border lines of higher and lower color ratio areas. Acknowledgment: This work has been supported by the German Space Agency (DLR) on behalf of the Federal Ministry for Economic Affairs and Energy, Germany, grants 50 OW

  4. Possible earthquake-generated wave deposits near Yellowstone Lake: Clues into triggering mechanisms of a large hydrothermal explosion crater

    Science.gov (United States)

    Morgan, L. A.; Shanks, W. P.; Pierce, K. L.

    2002-12-01

    Yellowstone National Park has experienced numerous hydrothermal explosions in the past and thre is no reason to suggest that such activity will diminish in the future. Craters and associated breccia deposits created from hydrothermal explosions are mapped as Holocene units throughout the Park, primarily within the 0.64-Ma Yellowstone caldera. The largest hydrothermal explosion crater in Yellowstone, referred herein as the Mary Bay explosion crater complex, has a diameter of 2 km by 1 km and is nested in Mary Bay in the northern basin of Yellowstone Lake, an area where extremely high heat flow values are measured. Formation of hydrothermal features in Yellowstone is related to convective meteoric hydrothermal fluid circulation above a magma chamber. Hydrothermal explosions result from accumulation and release of steam generated during hydrothermal fluid ascent, possibly reflecting changes in confining pressure that accompany and may accelerate failure and fragmentation of overlying lithologies. Sealing of surficial discharge conduits due to hydrothermal mineral precipitation contributes to over-pressuring and catastrophic failure. Exposed in wave-cut cliffs along Mary Bay north of Yellowstone Lake is a sedimentary sequence, which gives insight into the history of the Mary Bay hydrothermal explosion event. A sequence of lake sediments overlain by the Mary Bay hydrothermal explosion deposit is separated locally by an unusual dark, well sorted, cross-bedded, fine-grained sand layer. This unit is 1.5 to > 2 meters thick and contains numerous small en echelon faults. We conclude that this sand represents a deposit from an earthquake-generated tsunami-like wave, which in turn triggered the explosion of the Mary Bay crater complex. The potential of an event like this occuring today is currently under evaluation.

  5. Martian Atmospheric Methane Plumes from Meteor Shower Infall: A Hypothesis

    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.

    2016-01-01

    Methane plumes in the martian atmosphere have been detected using Earth-based spectroscopy, the Planetary Fourier Spectrometer on the ESA Mars Express mission, and the NASA Mars Science Laboratory. The methane's origin remains a mystery, with proposed sources including volcanism, exogenous sources like impacts and interplanetary dust, aqueous alteration of olivine in the presence of carbonaceous material, release from ancient deposits of methane clathrates, and/or biological activity. To date, none of these phenomena have been found to reliably correlate with the detection of methane plumes. An additional source exists, however: meteor showers could generate martian methane via UV pyrolysis of carbon-rich infall material. We find a correlation between the dates of Mars/cometary orbit encounters and detections of methane on Mars. We hypothesize that cometary debris falls onto Mars during these interactions, depositing freshly disaggregated meteor shower material in a regional concentration. The material generates methane via UV photolysis, resulting in a localized "plume" of short-lived methane.

  6. The Working Group on Meteor Showers Nomenclature: a History, Current Status and a Call for Contributions

    Science.gov (United States)

    Jopek, T. J.; Jenniskens, P. M.

    2011-01-01

    During the IAU General Assembly in Rio de Janeiro in 2009, the members of Commission 22 established the Working Group on Meteor Shower Nomenclature, from what was formerly the Task Group on Meteor Shower Nomenclature. The Task Group had completed its mission to propose a first list of established meteor showers that could receive officially names. At the business meeting of Commission 22 the list of 64 established showers was approved and consequently officially accepted by the IAU. A two-step process is adopted for showers to receive an official name from the IAU: i) before publication, all new showers discussed in the literature are first added to the Working List of Meteor Showers, thereby receiving a unique name, IAU number and three-letter code; ii) all showers which come up to the verification criterion are selected for inclusion in the List of Established Meteor Showers, before being officially named at the next IAU General Assembly.

  7. Distinguishing Endogenic and Impact Craters Using Depth to Diameter Ratios and Circularities

    Science.gov (United States)

    Dorsey, R. J.; Greeley, R.

    2011-03-01

    Based on concerns for surface age dating, morphometric data from the McCartys Flow, New Mexico, was compared to craters in the Colombia Hills area in Gusev Crater, Mars, to distinguish impact craters from volcanic craters in lava flows.

  8. Meteor studies in the framework of the JEM-EUSO program

    Science.gov (United States)

    Abdellaoui, G.; Abe, S.; Acheli, A.; Adams, J. H.; Ahmad, S.; Ahriche, A.; Albert, J.-N.; Allard, D.; Alonso, G.; Anchordoqui, L.; Andreev, V.; Anzalone, A.; Aouimeur, W.; Arai, Y.; Arsene, N.; Asano, K.; Attallah, R.; Attoui, H.; Ave Pernas, M.; Bacholle, S.; Bakiri, M.; Baragatti, P.; Barrillon, P.; Bartocci, S.; Batsch, T.; Bayer, J.; Bechini, R.; Belenguer, T.; Bellotti, R.; Belov, A.; Belov, K.; Benadda, B.; Benmessai, K.; Berlind, A. A.; Bertaina, M.; Biermann, P. L.; Biktemerova, S.; Bisconti, F.; Blanc, N.; Błȩcki, J.; Blin-Bondil, S.; Bobik, P.; Bogomilov, M.; Bonamente, M.; Boudaoud, R.; Bozzo, E.; Briggs, M. S.; Bruno, A.; Caballero, K. S.; Cafagna, F.; Campana, D.; Capdevielle, J.-N.; Capel, F.; Caramete, A.; Caramete, L.; Carlson, P.; Caruso, R.; Casolino, M.; Cassardo, C.; Castellina, A.; Castellini, G.; Catalano, C.; Catalano, O.; Cellino, A.; Chikawa, M.; Chiritoi, G.; Christl, M. J.; Connaughton, V.; Conti, L.; Cordero, G.; Crawford, H. J.; Cremonini, R.; Csorna, S.; Dagoret-Campagne, S.; De Donato, C.; de la Taille, C.; De Santis, C.; del Peral, L.; Di Martino, M.; Djemil, T.; Djenas, S. A.; Dulucq, F.; Dupieux, M.; Dutan, I.; Ebersoldt, A.; Ebisuzaki, T.; Engel, R.; Eser, J.; Fang, K.; Fenu, F.; Fernández-González, S.; Fernández-Soriano, J.; Ferrarese, S.; Finco, D.; Flamini, M.; Fornaro, C.; Fouka, M.; Franceschi, A.; Franchini, S.; Fuglesang, C.; Fujimoto, J.; Fukushima, M.; Galeotti, P.; García-Ortega, E.; Garipov, G.; Gascón, E.; Geary, J.; Gelmini, G.; Genci, J.; Giraudo, G.; Gonchar, M.; González Alvarado, C.; Gorodetzky, P.; Guarino, F.; Guehaz, R.; Guzmán, A.; Hachisu, Y.; Haiduc, M.; Harlov, B.; Haungs, A.; Hernández Carretero, J.; Hidber, W.; Higashide, K.; Ikeda, D.; Ikeda, H.; Inoue, N.; Inoue, S.; Isgrò, F.; Itow, Y.; Jammer, T.; Joven, E.; Judd, E. G.; Jung, A.; Jochum, J.; Kajino, F.; Kajino, T.; Kalli, S.; Kaneko, I.; Kang, D.; Kanouni, F.; Karadzhov, Y.; Karczmarczyk, J.; Karus, M.; Katahira, K.; Kawai, K.; Kawasaki, Y.; Kedadra, A.; Khales, H.; Khrenov, B. A.; Kim, Jeong-Sook; Kim, Soon-Wook; Kim, Sug-Whan; Kleifges, M.; Klimov, P. A.; Kolev, D.; Kreykenbohm, I.; Kudela, K.; Kurihara, Y.; Kusenko, A.; Kuznetsov, E.; Lacombe, M.; Lachaud, C.; Lahmar, H.; Lakhdari, F.; Larsson, O.; Lee, J.; Licandro, J.; Lim, H.; López Campano, L.; Maccarone, M. C.; Mackovjak, S.; Mahdi, M.; Maravilla, D.; Marcelli, L.; Marcos, J. L.; Marini, A.; Martens, K.; Martín, Y.; Martinez, O.; Masciantonio, G.; Mase, K.; Matev, R.; Matthews, J. N.; Mebarki, N.; Medina-Tanco, G.; Mehrad, L.; Mendoza, M. A.; Merino, A.; Mernik, T.; Meseguer, J.; Messaoud, S.; Micu, O.; Mimouni, J.; Miyamoto, H.; Miyazaki, Y.; Mizumoto, Y.; Modestino, G.; Monaco, A.; Monnier-Ragaigne, D.; Morales de los Ríos, J. A.; Moretto, C.; Morozenko, V. S.; Mot, B.; Murakami, T.; Nadji, B.; Nagano, M.; Nagata, M.; Nagataki, S.; Nakamura, T.; Napolitano, T.; Nardelli, A.; Naumov, D.; Nava, R.; Neronov, A.; Nomoto, K.; Nonaka, T.; Ogawa, T.; Ogio, S.; Ohmori, H.; Olinto, A. V.; Orleański, P.; Osteria, G.; Painter, W.; Panasyuk, M. I.; Panico, B.; Parizot, E.; Park, I. H.; Park, H. W.; Pastircak, B.; Patzak, T.; Paul, T.; Pennypacker, C.; Perdichizzi, M.; Pérez-Grande, I.; Perfetto, F.; Peter, T.; Picozza, P.; Pierog, T.; Pindado, S.; Piotrowski, L. W.; Piraino, S.; Placidi, L.; Plebaniak, Z.; Pliego, S.; Pollini, A.; Popescu, E. M.; Prat, P.; Prévôt, G.; Prieto, H.; Putis, M.; Rabanal, J.; Radu, A. A.; Rahmani, M.; Reardon, P.; Reyes, M.; Rezazadeh, M.; Ricci, M.; Rodríguez Frías, M. D.; Ronga, F.; Roth, M.; Rothkaehl, H.; Roudil, G.; Rusinov, I.; Rybczyński, M.; Sabau, M. D.; Sáez Cano, G.; Sagawa, H.; Sahnoune, Z.; Saito, A.; Sakaki, N.; Sakata, M.; Salazar, H.; Sanchez, J. C.; Sánchez, J. L.; Santangelo, A.; Santiago Crúz, L.; Sanz-Andrés, A.; Sanz Palomino, M.; Saprykin, O.; Sarazin, F.; Sato, H.; Sato, M.; Schanz, T.; Schieler, H.; Scotti, V.; Segreto, A.; Selmane, S.; Semikoz, D.; Serra, M.; Sharakin, S.; Shibata, T.; Shimizu, H. M.; Shinozaki, K.; Shirahama, T.; Siemieniec-Oziȩbło, G.; Sledd, J.; Słomińska, K.; Sobey, A.; Stan, I.; Sugiyama, T.; Supanitsky, D.; Suzuki, M.; Szabelska, B.; Szabelski, J.; Tahi, H.; Tajima, F.; Tajima, N.; Tajima, T.; Takahashi, Y.; Takami, H.; Takeda, M.; Takizawa, Y.; Talai, M. C.; Tenzer, C.; Tibolla, O.; Tkachev, L.; Tokuno, H.; Tomida, T.; Tone, N.; Toscano, S.; Traïche, M.; Tsenov, R.; Tsunesada, Y.; Tsuno, K.; Tymieniecka, T.; Uchihori, Y.; Unger, M.; Vaduvescu, O.; Valdés-Galicia, J. F.; Vallania, P.; Vankova, G.; Vigorito, C.; Villaseñor, L.; Vlcek, B.; von Ballmoos, P.; Vrabel, M.; Wada, S.; Watanabe, J.; Watanabe, S.; Watts, J., Jr.; Weber, M.; Weigand Muñoz, R.; Weindl, A.; Weiler, T. J.; Wibig, T.; Wiencke, L.; Wille, M.; Wilms, J.; Włodarczyk, Z.; Yamamoto, T.; Yamamoto, Y.; Yang, J.; Yano, H.; Yashin, I. V.; Yonetoku, D.; Yoshida, S.; Young, R.; Zgura, I. S.; Zotov, M. Yu.; Zuccaro Marchi, A.

    2017-09-01

    We summarize the state of the art of a program of UV observations from space of meteor phenomena, a secondary objective of the JEM-EUSO international collaboration. Our preliminary analysis indicates that JEM-EUSO, taking advantage of its large FOV and good sensitivity, should be able to detect meteors down to absolute magnitude close to 7. This means that JEM-EUSO should be able to record a statistically significant flux of meteors, including both sporadic ones, and events produced by different meteor streams. Being unaffected by adverse weather conditions, JEM-EUSO can also be a very important facility for the detection of bright meteors and fireballs, as these events can be detected even in conditions of very high sky background. In the case of bright events, moreover, exhibiting some persistence of the meteor train, preliminary simulations show that it should be possible to exploit the motion of the ISS itself and derive at least a rough 3D reconstruction of the meteor trajectory. Moreover, the observing strategy developed to detect meteors may also be applied to the detection of nuclearites, exotic particles whose existence has been suggested by some theoretical investigations. Nuclearites are expected to move at higher velocities than meteoroids, and to exhibit a wider range of possible trajectories, including particles moving upward after crossing the Earth. Some pilot studies, including the approved Mini-EUSO mission, a precursor of JEM-EUSO, are currently operational or in preparation. We are doing simulations to assess the performance of Mini-EUSO for meteor studies, while a few meteor events have been already detected using the ground-based facility EUSO-TA.

  9. Diurnal and annual variations of meteor rates at the arctic circle

    Directory of Open Access Journals (Sweden)

    W. Singer

    2004-01-01

    Full Text Available Meteors are an important source for (a the metal atoms of the upper atmosphere metal layers and (b for condensation nuclei, the existence of which are a prerequisite for the formation of noctilucent cloud particles in the polar mesopause region. For a better understanding of these phenomena, it would be helpful to know accurately the annual and diurnal variations of meteor rates. So far, these rates have been little studied at polar latitudes. Therefore we have used the 33 MHz meteor radar of the ALOMAR observatory at 69° N to measure the meteor rates at this location for two full annual cycles. This site, being within 3° of the Arctic circle, offers in addition an interesting capability: The axis of its antenna field points (almost towards the North ecliptic pole once each day of the year. In this particular viewing direction, the radar monitors the meteoroid influx from (almost the entire ecliptic Northern hemisphere. We report on the observed diurnal variations (averaged over one month of meteor rates and their significant alterations throughout the year. The ratio of maximum over minimum meteor rates throughout one diurnal cycle is in January and February about 5, from April through December 2.3±0.3. If compared with similar measurements at mid-latitudes, our expectation, that the amplitude of the diurnal variation is to decrease towards the North pole, is not really borne out. Observations with the antenna axis pointing towards the North ecliptic pole showed that the rate of deposition of meteoric dust is substantially larger during the Arctic NLC season than the annual mean deposition rate. The daylight meteor showers of the Arietids, Zeta Perseids, and Beta Taurids supposedly contribute considerably to the June maximum of meteor rates. We note, though, that with the radar antenna pointing as described above, all three meteor radiants are close to the local horizon but all three radiants were detected.

  10. Experimental investigation of crater growth dynamics

    Science.gov (United States)

    Schmidt, R. M.; Housen, K. R.; Bjorkman, M. D.; Holsapple, K. A.

    1985-01-01

    This work is a continuation of an ongoing program whose objective is to perform experiments and to develop scaling relationships for large-body impacts onto planetary surfaces. The centrifuge technique is used to provide experimental data for actual target materials of interest. With both power and gas guns mounted on the rotor arm, it is possible to match various dimensionless similarity parameters, which have been shown to govern the behavior of large-scale impacts. The development of the centrifuge technique has been poineered by the present investigators and is documented by numerous publications, the most recent of which are listed below. Understanding the dependence of crater size upon gravity has been shown to be key to the complete determination of the dynamic and kinematic behavior of crater formation as well as ejecta phenomena. Three unique time regimes in the formation of an impact crater have been identified.

  11. Crater monitoring through social media observations

    Science.gov (United States)

    Gialampoukidis, I.; Vrochidis, S.; Kompatsiaris, I.

    2017-09-01

    We have collected more than one lunar image per two days from social media observations. Each one of the collected images has been clustered into two main groups of lunar images and an additional cluster is provided (noise) with pictures that have not been assigned to any cluster. The proposed lunar image clustering process provides two classes of lunar pictures, at different zoom levels; the first showing a clear view of craters grouped into one cluster and the second demonstrating a complete view of the Moon at various phases that are correlated with the crawling date. The clustering stage is unsupervised, so new topics can be detected on-the-fly. We have provided additional sources of planetary images using crowdsourcing information, which is associated with metadata such as time, text, location, links to other users and other related posts. This content has crater information that can be fused with other planetary data to enhance crater monitoring.

  12. Physics of soft impact and cratering

    CERN Document Server

    Katsuragi, Hiroaki

    2016-01-01

    This book focuses on the impact dynamics and cratering of soft matter to describe its importance, difficulty, and wide applicability to planetary-related problems. A comprehensive introduction to the dimensional analysis and constitutive laws that are necessary to discuss impact mechanics and cratering is first provided. Then, particular coverage is given to the impact of granular matter, which is one of the most crucial constituents for geophysics. While granular matter shows both solid-like and fluid-like behaviors, neither solid nor fluid dynamics is sufficient to fully understand the physics of granular matter. In order to reveal its fundamental properties, extensive impact tests have been carried out recently. The author reveals the findings of these recent studies as well as what remains unsolved in terms of impact dynamics. Impact crater morphology with various soft matter impacts also is discussed intensively. Various experimental and observational results up to the recent Itokawa asteroid’s terrain...

  13. Radar observations of meteor trails, and their interpretation using Fresnel holography: a new tool in meteor science

    Directory of Open Access Journals (Sweden)

    W. G. Elford

    2004-01-01

    Full Text Available A Fresnel transform technique has been developed at Adelaide to analyse radar meteor echoes detected in the transverse mode. The genesis for this technique was the study of the structure of the scattering ionization immediately behind the head of the trail, in order to deduce the degree of fragmentation of the ablating meteoroid. The technique has been remarkably successful in not only giving insight into the fragmentation of meteoroids, but also revealing other significant features of the trails including diffusion, lateral motion of the trail during formation due to wind drift, and phase of the scattered signal in the vicinity of the head of the trail. A serendipitous outcome of the analysis is the measurement of the speed and deceleration of the meteoroid producing the trail to a precision far exceeding that available from any other method applied to transverse scatter data. Examples of the outcomes of the technique applied to meteor echoes obtained with a 54MHz narrow beam radar are presented.

  14. Titan's Impact Cratering Record: Erosion of Ganymedean (and other) Craters on a Wet Icy Landscape

    Science.gov (United States)

    Schenk, P.; Moore, J.; Howard, A.

    2012-04-01

    We examine the cratering record of Titan from the perspective of icy satellites undergoing persistent landscape erosion. First we evaluate whether Ganymede (and Callisto) or the smaller low-gravity neighboring icy satellites of Saturn are the proper reference standard for evaluating Titan’s impact crater morphologies, using topographic and morphometric measurements (Schenk, 2002; Schenk et al. (2004) and unpublished data). The special case of Titan’s largest crater, Minrva, is addressed through analysis of large impact basins such as Gilgamesh, Lofn, Odysseus and Turgis. Second, we employ a sophisticated landscape evolution and modification model developed for study of martian and other planetary landforms (e.g., Howard, 2007). This technique applies mass redistribution principles due to erosion by impact, fluvial and hydrological processes to a planetary landscape. The primary advantage of our technique is the possession of a limited but crucial body of areal digital elevation models (DEMs) of Ganymede (and Callisto) impact craters as well as global DEM mapping of Saturn’s midsize icy satellites, in combination with the ability to simulate rainfall and redeposition of granular material to determine whether Ganymede craters can be eroded to resemble Titan craters and the degree of erosion required. References: Howard, A. D., “Simulating the development of martian highland landscapes through the interaction of impact cratering, fluvial erosion, and variable hydrologic forcing”, Geomorphology, 91, 332-363, 2007. Schenk, P. "Thickness constraints on the icy shells of the galilean satellites from impact crater shapes". Nature, 417, 419-421, 2002. Schenk, P.M., et al. "Ages and interiors: the cratering record of the Galilean satellites". In: Jupiter: The Planet, Satellites, and Magnetosphere, Cambridge University Press, Cambridge, UK, pp. 427-456, 2004.

  15. 'Sharks Teeth' -- Sand Dunes in Proctor Crater

    Science.gov (United States)

    2001-01-01

    Sometimes, pictures received from Mars Global Surveyor's Mars Orbiter Camera (MOC) are 'just plain pretty.' This image, taken in early September 2000, shows a group of sand dunes at the edge of a much larger field of dark-toned dunes in Proctor Crater. Located at 47.9oS, 330.4oW, in the 170 km (106 mile) diameter crater named for 19th Century British astronomer Richard A. Proctor (1837-1888), the dunes shown here are created by winds blowing largely from the east/northeast. A plethora of smaller, brighter ripples covers the substrate between the dunes. Sunlight illuminates them from the upper left.

  16. North Rim of Endeavour Crater on Horizon

    Science.gov (United States)

    2009-01-01

    [figure removed for brevity, see original site] A northern portion of the rim of Endeavour Crater is visible on the horizon of this image taken by the panoramic camera (Pancam) on NASA's Mars Exploration Rover Opportunity on March 7, 2009, during the 1,820st Martian day, or sol, of the rover's mission on Mars. That portion of Endeavour's rim is about 20 kilometers (12 miles) away from Opportunity's position west of the crater when the image was taken. The width of the image covers approximately one degree of the horizon.

  17. East Rim of Endeavour Crater on Horizon

    Science.gov (United States)

    2009-01-01

    [figure removed for brevity, see original site] A high point on the distant eastern rim of Endeavour Crater is visible on the horizon in this image taken by the panoramic camera (Pancam) on NASA's Mars Exploration Rover Opportunity on March 8, 2009, during the 1,821st Martian day, or sol, of the rover's mission on Mars. That portion of Endeavour's rim is about 34 kilometers (21 miles) away from Opportunity's position west of the crater when the image was taken. The width of the image covers approximately one degree of the horizon.

  18. View of the crater on lunar farside from Apollo 13

    Science.gov (United States)

    1970-01-01

    This bright-rayed crater on the lunar farside was photographed from the Apollo 13 spacecraft during its pass around the Moon. This area is northeast of Mare Marginus. The bright-rayed crater is located at about 105 degrees east longitude and 45 degrees north latitude. The crater Joliot-Curie is located between Mare Marginus and the rayed crater. This view is looking generally toward the northeast.

  19. Development of a Remote Monitoring System Using Meteor Burst Technology

    International Nuclear Information System (INIS)

    Ewanic, M.A.; Dunstan, M.T.; Reichhardt, D.K.

    2006-01-01

    Monitoring the cleanup and closure of contaminated sites requires extensive data acquisition, processing, and storage. At remote sites, the task of monitoring often becomes problematical due to the lack of site infrastructure (i.e., electrical power lines, telephone lines, etc.). MSE Technology Applications, Inc. (MSE) has designed an economical and efficient remote monitoring system that will handle large amounts of data; process the data, if necessary; and transmit this data over long distances. Design criteria MSE considered during the development of the remote monitoring system included: the ability to handle multiple, remote sampling points with independent sampling frequencies; robust (i.e., less susceptible to moisture, heat, and cold extremes); independent of infrastructure; user friendly; economical; and easy to expand system capabilities. MSE installed and tested a prototype system at the Mike Mansfield Advanced Technology Center (MMATC), Butte, Montana, in June 2005. The system MSE designed and installed consisted of a 'master' control station and two remote 'slave' stations. Data acquired at the two slave stations were transmitted to the master control station, which then transmits a complete data package to a ground station using meteor burst technology. The meteor burst technology has no need for hardwired land-lines or man-made satellites. Instead, it uses ionized particles in the Earth's atmosphere to propagate a radio signal. One major advantage of the system is that it can be configured to accept data from virtually any type of device, so long as the signal from the device can be read and recorded by a standard data-logger. In fact, MSE has designed and built an electrical resistivity monitoring system that will be powered and controlled by the meteor burst system components. As sites move through the process of remediation and eventual closure, monitoring provides data vital to the successful long term management of the site. The remote

  20. Crater ejecta scaling laws: fundamental forms based on dimensional analysis

    International Nuclear Information System (INIS)

    Housen, K.R.; Schmidt, R.M.; Holsapple, K.A.

    1983-01-01

    A model of crater ejecta is constructed using dimensional analysis and a recently developed theory of energy and momentum coupling in cratering events. General relations are derived that provide a rationale for scaling laboratory measurements of ejecta to larger events. Specific expressions are presented for ejection velocities and ejecta blanket profiles in two limiting regimes of crater formation: the so-called gravity and strength regimes. In the gravity regime, ejectra velocities at geometrically similar launch points within craters vary as the square root of the product of crater radius and gravity. This relation implies geometric similarity of ejecta blankets. That is, the thickness of an ejecta blanket as a function of distance from the crater center is the same for all sizes of craters if the thickness and range are expressed in terms of crater radii. In the strength regime, ejecta velocities are independent of crater size. Consequently, ejecta blankets are not geometrically similar in this regime. For points away from the crater rim the expressions for ejecta velocities and thickness take the form of power laws. The exponents in these power laws are functions of an exponent, α, that appears in crater radius scaling relations. Thus experimental studies of the dependence of crater radius on impact conditions determine scaling relations for ejecta. Predicted ejection velocities and ejecta-blanket profiles, based on measured values of α, are compared to existing measurements of velocities and debris profiles

  1. Using THEMIS thermal infrared observations of rays from Corinto crater to study secondary crater formation on Mars

    Science.gov (United States)

    Williams, J. P.

    2017-12-01

    Corinto crater (16.95°N, 141.72°E), a 13.8 km diameter crater in Elysium Planitia, displays dramatic rays in Mars Odyssey's Thermal Emission Imaging System (THEMIS) nighttime infrared imagery where high concentrations of secondary craters have altered the thermophysical properties of the martian surface. The THEMIS observations provide a record of secondary crater formation in the region and ray segments are identified up to 2000 km ( 145 crater radii) distance [1][2]. Secondary craters are likely to have the largest influence on model surfaces ages between 0.1 to a few Myr as there is the potential for one or two sizeable craters to project secondary craters onto those surfaces and thus alter the crater size-frequency distribution (CSFD) with an instantaneous spike in crater production [3]. Corinto crater is estimated to be less than a few Ma [4] placing the formation of its secondaries within this formative time period. Secondary craters superposed on relatively young impact craters that predate Corinto provide observations of the secondary crater populations. Crater counts at 520 and 660 km distance from Corinto (38 and 48 crater radii respectively), were conducted. Higher crater densities were observed within ray segments, however secondary craters still influenced the CSFD where ray segments were not apparent, resulting in steepening in the CSFD. Randomness analysis confirms an increase in clustering as diameters decrease suggesting an increasing fraction of secondary craters at smaller diameters, both within the ray and outside. The counts demonstrate that even at nearly 50 crater radii, Corinto secondaries still influence the observed CSFD, even outside of any obvious rays. Crater populations used to derive model ages on many geologically young regions on Mars, such as glacial and periglacial landforms related to obliquity excursions that occur on 106 - 107 yr cycles, should be used cautiously and analyzed for any evidence, either morphologic or

  2. A MATLAB-based planar array design assistant package with applications to meteor radar systems

    Science.gov (United States)

    Kang, C.; Palo, S.

    Interferometric techniques are commonly used in all-sky meteor radar systems for meteor location determination Essentially interferometric techniques use the phase information recorded from different receiving antennas to estimate the elevation and azimuth of the meteors Prior efforts have been made to determine an antenna geometry that improves the performance of meteor radar systems For example Hocking and Thayaparan 1997 used four antennas typically spaced by 1 5 to 3 wavelengths to locate the meteors Jones 1992 and Hocking 1997 presented an antenna geometry using a 5 element array with minimum antenna spacing of 2 wavelengths to estimate the direction of arrival DOA of the meteors By spacing the antennas more than 2 wavelength apart these array geometries were successful in reducing the electromagnetic coupling effect between the antennas which can introduce errors in the estimation of meteor locations Without a clear metric for performance it is difficult to compare geometries In this work a MATLAB planar antenna array package mainly designed for visualization of the direction of arrival DOA estimation performance of arbitrary user designed antenna array is presented Performance comparisons of nominal array geometries are also provided Several metrics are available in this package in an effort to provide the user with a comprehensive examination of an array s performance The metrics are the Cramer-Rao bound CRB which is the minimum variance that can be obtained for any unbiased estimator the co-array the

  3. Performance of D-Parameters in Isolating Meteor Showers from the Sporadic Background

    Science.gov (United States)

    Moorhead, Althea

    2016-01-01

    It is often necessary to draw a division between meteor showers and the sporadic meteor complex in order to study these components of the meteoroid environment. Meteor showers persist for less than a season and are composed of members with a greater-than-average degree of orbital similarity. The level of orbital similarity is often quantified using so-called D-parameters; a D-parameter cutoff may be employed to define or extract a shower. Depending on the study, this cutoff value may be chosen based on the size of the data-set, the percentage of sporadic meteors within the data-set, or the inclination of the shower in question. We argue that the cutoff value should also reject the strength of the shower compared to the local sporadic background. We therefore present a method for determining, on a per-shower basis, the D-parameter cutoff that limits the false-positive rate to an acceptable percentage. If the false-positive rate exceeds this percentage regardless of cutoff value, we deem the shower to be undetectable in our data. We apply this method to optical meteor observations from the NASA All-Sky and Southern Ontario Meteor Networks and present the detectable meteor showers and their characteristics.

  4. METEOR v1.0 - Design and structure of the software package

    International Nuclear Information System (INIS)

    Palomo, E.

    1994-01-01

    This script describes the structure and the separated modules of the software package METEOR for the statistical analysis of meteorological data series. It contains a systematic description of the subroutines of METEOR and, also, of the required shape for input and output files. 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 thc 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 v 1.0: Design and structure of the software package. (Author)

  5. New aspects in single-body meteor physics

    Science.gov (United States)

    Pecina, P.; Ceplecha, Z.

    1983-03-01

    An exact analytical solution of the atmospheric meteoroid single-body problem is presented expressing the distance along the trajectory as a function of time, which yields a least-square fit of the observed trajectory, and analytical expressions for the velocity at the point of maximum deceleration are derived. These results are used to determine the ablation coefficient from observations. These methods are applied to 17 Prairie Network fireballs observed below the maximum deceleration point and to the Innisfree fireball, and the results are found to be superior to the ones obtained with the usual interpolation formula. A model of luminous efficiencies for small velocities and for masses up to several hundred grams based on data on Innisfree and on artificial rocketry meteors is proposed and applied to separate the shape-density coefficient from the meteoroid mass.

  6. Automated Meteor Detection by All-Sky Digital Camera Systems

    Science.gov (United States)

    Suk, Tomáš; Šimberová, Stanislava

    2017-12-01

    We have developed a set of methods to detect meteor light traces captured by all-sky CCD cameras. Operating at small automatic observatories (stations), these cameras create a network spread over a large territory. Image data coming from these stations are merged in one central node. Since a vast amount of data is collected by the stations in a single night, robotic storage and analysis are essential to processing. The proposed methodology is adapted to data from a network of automatic stations equipped with digital fish-eye cameras and includes data capturing, preparation, pre-processing, analysis, and finally recognition of objects in time sequences. In our experiments we utilized real observed data from two stations.

  7. 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

  8. Earth-viewing satellite perspectives on the Chelyabinsk meteor event.

    Science.gov (United States)

    Miller, Steven D; Straka, William C; Bachmeier, A Scott; Schmit, Timothy J; Partain, Philip T; Noh, Yoo-Jeong

    2013-11-05

    Large meteors (or superbolides [Ceplecha Z, et al. (1999) Meteoroids 1998:37-54]), although rare in recorded history, give sobering testimony to civilization's inherent vulnerability. A not-so-subtle reminder came on the morning of February 15, 2013, when a large meteoroid hurtled into the Earth's atmosphere, forming a superbolide near the city of Chelyabinsnk, Russia, ∼1,500 km east of Moscow, Russia [Ivanova MA, et al. (2013) Abstracts of the 76th Annual Meeting of the Meteoritical Society, 5366]. The object exploded in the stratosphere, and the ensuing shock wave blasted the city of Chelyabinsk, damaging structures and injuring hundreds. Details of trajectory are important for determining its specific source, the likelihood of future events, and potential mitigation measures. Earth-viewing environmental satellites can assist in these assessments. Here we examine satellite observations of the Chelyabinsk superbolide debris trail, collected within minutes of its entry. Estimates of trajectory are derived from differential views of the significantly parallax-displaced [e.g., Hasler AF (1981) Bull Am Meteor Soc 52:194-212] debris trail. The 282.7 ± 2.3° azimuth of trajectory, 18.5 ± 3.8° slope to the horizontal, and 17.7 ± 0.5 km/s velocity derived from these satellites agree well with parameters inferred from the wealth of surface-based photographs and amateur videos. More importantly, the results demonstrate the general ability of Earth-viewing satellites to provide valuable insight on trajectory reconstruction in the more likely scenario of sparse or nonexistent surface observations.

  9. Measurement of momentum flux using two meteor radars in Indonesia

    Directory of Open Access Journals (Sweden)

    N. Matsumoto

    2016-03-01

    Full Text Available Two nearly identical meteor radars were operated at Koto Tabang (0.20° S, 100.32° E, West Sumatra, and Biak (1.17° S, 136.10° E, West Papua, in Indonesia, separated by approximately 4000 km in longitude on the Equator. The zonal and meridional momentum flux, u′w′ and v′w′, where u, v, and w are the eastward, northward, and vertical wind velocity components, respectively, were estimated at 86 to 94 km altitudes using the meteor radar data by applying a method proposed by Hocking (2005. The observed u′w′ at the two sites agreed reasonably well at 86, 90, and 94 km during the observation periods when the data acquisition rate was sufficiently large enough. Variations in v′w′ were consistent between 86, 90, and 94 km altitudes at both sites. The climatological variation in the monthly averaged u′w′ and v′w′ was investigated using the long-term radar data at Koto Tabang from November 2002 to November 2013. The seasonal variations in u′w′ and v′w′ showed a repeatable semiannual and annual cycles, respectively. u′w′ showed eastward values in February–April and July–September and v′w′ was northward in June to August at 90–94 km, both of which were generally anti-phase with the mean zonal and meridional winds, having the same periodicity. Our results suggest the usefulness of the Hocking method.

  10. Implications of a global survey of venusian impact craters

    Science.gov (United States)

    Herrick, Robert R.; Phillips, Roger J.

    1994-01-01

    We present a global survey of the areal distribution, size-frequency distribution, and morphometric properties of the venusian impact cratering record. We explore the resurfacing history of Venus, crater degradation, ejecta emplacement, and cratering mechanics. The number of volcanically embayed and tectonically deformed craters from 0.5 to 1.0 km above mean planetary radius is disproportionately high for an otherwise crater-deficient elevation range. More resurfacing occurred in this range, an elevation range dominated by volcanic rises, rifts, and coronae, than elsewhere on Venus. Although the majority of craters appear to be relatively undisturbed and have intact ejecta blankets, some craters appear particularly `fresh' because thay have radar-bright floors, a radar-dark halo surrounding the ejecta blanket, and a west facing parabola of low radar return; 20, 35, and 8%, respectively, of craters with diameters greater than 22.6 km have these features. Characteristics of ejecta deposits for venusian craters change substantially with size, particularly at 20 km crater diameter, which marks the transition at which the boundaries of ejecta blankets go from ragged to lobate and the slope of the ejecta distance vs diameter curve steepens. Secondary craters are a ubiquitous part of the ejecta blanket for craters over 50 km but occur infrequently as isolated rays about smaller craters. Comparison of complex craters found on Venus with those of other planets gave results that were consistent with the idea that interplanetary differences in complex crater shape are controlled by interplanetary differences in gravity and crustal strength. The interplanetary comparison indicates that Venus, the Moon, and Mercury appear to have stronger crusts than do Mars and Ganymede/Callisto.

  11. Some Studies of Terrestrial Impact Cratering Rate

    Directory of Open Access Journals (Sweden)

    Jetsu L.

    2011-06-01

    Full Text Available In 1984, a 28.4 Myr periodicity was detected in the ages of terrestrial impact craters and a 26 Myr periodicity in the epochs of mass extinctions of species. Periodic comet showers from the Oort cloud seemed to cause catastrophic events linked to mass extinctions of species. Our first study revealed that the only significant detected periodicity is the “human signal” caused by the rounding of these data into integer numbers. The second study confirmed that the original 28.4 Myr periodicity detection was not significant. The third study revealed that the quality and the quantity of the currently available data would allow detection of real periodicity only if all impacts have been periodic, which cannot be the case. The detection of a periodic signal, if present, requires that more craters should be discovered and the accuracy of age estimates improved. If we sometimes will be able to find the difference between the craters caused by asteroid and comet impacts, the aperiodic component could be removed. The lunar impact craters may eventually provide the required supplementary data.

  12. Signs of Landscape Modifications at Martian Crater

    Science.gov (United States)

    2009-01-01

    [figure removed for brevity, see original site] Click on the image for larger version The lower portion of this image from the Thermal Emission Imaging System camera (THEMIS) on NASA's Mars Odyssey orbiter shows a crater about 16 kilometers (10 miles) in diameter with features studied as evidence of deposition or erosion. The crater is centered at 40.32 degrees south latitude and 132.5 degrees east longitude, in the eastern portion of the Hellas basin on Mars. It has gullies and arcuate ridges on its north, pole-facing interior wall. This crater is in the center of a larger (60-kilometer or 37-mile diameter) crater with lobate flows on its north, interior wall. The image, number V07798008 in the THEMIS catalog, covers a swath of ground 17.4 kilometers (10.8 miles) wide. NASA's Jet Propulsion Laboratory manages the Mars Odyssey mission for NASA's Office of Space Science. THEMIS was developed by Arizona State University in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  13. Cepstrum Analysis of Terrestrial Impact Crater Records

    Directory of Open Access Journals (Sweden)

    Heon-Young Chang

    2008-06-01

    Full Text Available Study of terrestrial impact craters is important not only in the field of the solar system formation and evolution but also of the Galactic astronomy. The terrestrial impact cratering record recently has been examined, providing short- and intermediate-term periodicities, such as, Myrs, Myrs. The existence of such a periodicity has an implication in the Galactic dynamics, since the terrestrial impact cratering is usually interpreted as a result of the environmental variation during solar orbiting in the Galactic plane. The aim of this paper is to search for a long-term periodicity with a novel method since no attempt has been made so far in searching a long-term periodicity in this research field in spite of its great importance. We apply the cepstrum analysis method to the terrestrial impact cratering record for the first time. As a result of the analysis we have found noticeable peaks in the Fourier power spectrum appear ing at periods of Myrs and Myrs, which seem in a simple resonance with the revolution period of the Sun around the Galactic center. Finally we briefly discuss its implications and suggest theoretical study be pursued to explain such a long-term periodicity.

  14. The Carancas meteorite impact crater, Peru: Geologic surveying and modeling of crater formation and atmospheric passage

    Science.gov (United States)

    Kenkmann, T.; Artemieva, N. A.; Wünnemann, K.; Poelchau, M. H.; Elbeshausen, D.; Núñez Del Prado, H.

    2009-08-01

    The recent Carancas meteorite impact event caused a worldwide sensation. An H4-5 chondrite struck the Earth south of Lake Titicaca in Peru on September 15, 2007, and formed a crater 14.2 m across. It is the smallest, youngest, and one of two eye-witnessed impact crater events on Earth. The impact violated the hitherto existing view that stony meteorites below a size of 100 m undergo major disruption and deceleration during their passage through the atmosphere and are not capable of producing craters. Fragmentation occurs if the strength of the meteoroid is less than the aerodynamic stresses that occur in flight. The small fragments that result from a breakup rain down at terminal velocity and are not capable of producing impact craters. The Carancas cratering event, however, demonstrates that meter-sized stony meteoroids indeed can survive the atmospheric passage under specific circumstances. We present results of a detailed geologic survey of the crater and its ejecta. To constrain the possible range of impact parameters we carried out numerical models of crater formation with the iSALE hydrocode in two and three dimensions. Depending on the strength properties of the target, the impact energies range between approximately 100-1000 MJ (0.024- 0.24 t TNT). By modeling the atmospheric traverse we demonstrate that low cosmic velocities (12- 14 kms-1) and shallow entry angles (<20°) are prerequisites to keep aerodynamic stresses low (<10 MPa) and thus to prevent fragmentation of stony meteoroids with standard strength properties. This scenario results in a strong meteoroid deceleration, a deflection of the trajectory to a steeper impact angle (40-60°), and an impact velocity of 350-600 ms-1, which is insufficient to produce a shock wave and significant shock effects in target minerals. Aerodynamic and crater modeling are consistent with field data and our microscopic inspection. However, these data are in conflict with trajectories inferred from the analysis of

  15. 'Lyell' Panorama inside Victoria Crater (False Color)

    Science.gov (United States)

    2008-01-01

    Photojournal note: This very large image (487.9 MB TIFF and 17.71 MB JPEG) may be too large for some web browsers to handle. Users may right-click on the TIFF or JPEG link in the legend above to download the file to their desktop. The image can then be viewed in an image manipulation application such as Adobe Photoshop. During four months prior to the fourth anniversary of its landing on Mars, NASA's Mars Exploration Rover Opportunity examined rocks inside an alcove called 'Duck Bay' in the western portion of Victoria Crater. The main body of the crater appears in the upper right of this stereo panorama, with the far side of the crater lying about 800 meters (half a mile) away. Bracketing that part of the view are two promontories on the crater's rim at either side of Duck Bay. They are 'Cape Verde,' about 6 meters (20 feet) tall, on the left, and 'Cabo Frio,' about 15 meters (50 feet) tall, on the right. The rest of the image, other than sky and portions of the rover, is ground within Duck Bay. Opportunity's targets of study during the last quarter of 2007 were rock layers within a band exposed around the interior of the crater, about 6 meters (20 feet) from the rim. Bright rocks within the band are visible in the foreground of the panorama. The rover science team assigned informal names to three subdivisions of the band: 'Steno,' 'Smith,' and 'Lyell.' This view combines many images taken by Opportunity's panoramic camera (Pancam) from the 1,332nd through 1,379th Martian days, or sols, of the mission (Oct. 23 to Dec. 11, 2007). Images taken through Pancam filters centered on wavelengths of 753 nanometers, 535 nanometers and 432 nanometers were mixed to produce this view, which is presented in a false-color stretch to bring out subtle color differences in the scene. Some visible patterns in dark and light tones are the result of combining frames that were affected by dust on the front sapphire window of the rover's camera. Opportunity landed on Jan. 25, 2004

  16. Autonomous spectrographic system to analyse the main elements of fireballs and meteors

    Science.gov (United States)

    Espartero, Francisco Ángel; Martínez, Germán; Frías, Marta; Montes Moya, Francisco Simón; Castro-Tirado, Alberto Javier

    2018-01-01

    We present a meteor observation system based on imaging CCD cameras, wide-field optics and a diffraction grating. This system is composed of two independent spectrographs with different configurations, which allows us to capture images of fireballs and meteors with several fields of view and sensitivities. The complete set forms a small autonomous observatory, comprised of a sealed box with a sliding roof, weather station and computers for data storing and reduction. Since 2014, several meteors have been studied using this facility, such as the Alcalá la Real fireball recorded on 30 September 2016.

  17. Developing Dynamic Single Page Web Applications Using Meteor : Comparing JavaScript Frameworks: Blaze and React

    OpenAIRE

    Yetayeh, Asabeneh

    2017-01-01

    This paper studies Meteor which is a JavaScript full-stack framework to develop interactive single page web applications. Meteor allows building web applications entirely in JavaScript. Meteor uses Blaze, React or AngularJS as a view layer and Node.js and MongoDB as a back-end. The main purpose of this study is to compare the performance of Blaze and React. A multi-user Blaze and React web applications with similar HTML and CSS were developed. Both applications were deployed on Heroku’s w...

  18. 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.

  19. Ganymede and Callisto - Complex crater formation and planetary crusts

    Science.gov (United States)

    Schenk, Paul M.

    1991-01-01

    Results are presented on measurements of crater depths and other morphological parameters (such as central peak and terrace frequency) of fresh craters on Ganymede and Callisto, two geophysically very similar but geologically divergent large icy satellites of Jupiter. These data were used to investigate the crater mechanics on icy satellites and the intersatellite crater scaling and crustal properties. The morphological transition diameters of and complex crater depths on Ganymede and Callisto were found to be similar, indicating that the crusts of both satellites are dominated by water ice with only a minor rocky component.

  20. Meteoric 10Be as a tool to investigate human induced soil fluxes: a conceptual model

    Science.gov (United States)

    Campforts, Benjamin; Govers, Gerard; Vanacker, Veerle; De Vente, Joris; Boix-Fayos, Carolina; Minella, Jean; Baken, Stijn; Smolders, Erik

    2014-05-01

    The use of meteoric 10Be as a tool to understand long term landscape behavior is becoming increasingly popular. Due its high residence time, meteoric 10Be allows in principle to investigate in situ erosion rates over time scales exceeding the period studied with classical approaches such as 137Cs. The use of meteoric 10Be strongly contributes to the traditional interpretation of sedimentary archives which cannot be unequivocally coupled to sediment production and could provide biased information over longer time scales (Sadler, 1981). So far, meteoric 10Be has successfully been used in geochemical fingerprinting of sediments, to date soil profiles, to assess soil residence times and to quantify downslope soil fluxes using accumulated 10Be inventories along a hill slope. However, less attention is given to the potential use of the tracer to directly asses human induced changes in soil fluxes through deforestation, cultivation and reforestation. A good understanding of the processes governing the distribution of meteoric 10Be both within the soil profile and at landscape scale is essential before meteoric 10Be can be successfully applied to assess human impact. We developed a spatially explicit 2D-model (Be2D) in order to gain insight in meteoric 10Be movement along a hillslope that is subject to human disturbance. Be2D integrates both horizontal soil fluxes and vertical meteoric 10Be movement throughout the soil prolife. Horizontal soil fluxes are predicted using (i) well studied geomorphical laws for natural erosion and soil formation as well as (ii) human accelerated water and tillage erosion. Vertical movement of meteoric 10Be throughout the soil profile is implemented by inserting depth dependent retardation calculated using experimentally determined partition coefficients (Kd). The model was applied to different environments such as (i) the Belgian loess belt, characterized by aeolian deposits enriched in inherited meteoric 10Be, (ii) highly degraded and stony

  1. Automated detection and classification for craters based on geometric matching

    Science.gov (United States)

    Chen, Jian-qing; Cui, Ping-yuan; Cui, Hui-tao

    2011-08-01

    Crater detection and classification are critical elements for planetary mission preparations and landing site selection. This paper presents a methodology for the automated detection and matching of craters on images of planetary surface such as Moon, Mars and asteroids. For craters usually are bowl shaped depression, craters can be figured as circles or circular arc during landing phase. Based on the hypothesis that detected crater edges is related to craters in a template by translation, rotation and scaling, the proposed matching method use circles to fitting craters edge, and align circular arc edges from the image of the target body with circular features contained in a model. The approach includes edge detection, edge grouping, reference point detection and geometric circle model matching. Finally we simulate planetary surface to test the reasonableness and effectiveness of the proposed method.

  2. Hailar crater - A possible impact structure in Inner Mongolia, China

    Science.gov (United States)

    Xiao, Zhiyong; Chen, Zhaoxu; Pu, Jiang; Xiao, Xiao; Wang, Yichen; Huang, Jun

    2018-04-01

    Hailar crater, a probable impact structure, is a circular depression about 300 m diameter in Inner Mongolia, northeast China. With broad elevated rims, the present rim-to-floor depth is 8-20 m. Regional geological background and geomorphological comparison suggest that this feature is likely not formed by surface processes such as salt diapir, karst, aeolian, glacial, or volcanic activity. Its unique occurrence in this region and well-preserved morphology are most consistent with it being a Cenozoic impact crater. Two field expeditions in 2016 and 2017 investigated the origin of this structure, recognizing that (1) no additional craters were identified around Hailar crater in the centimeter-scale digital topography models that were constructed using a drone imaging system and stereo photogrammetry; (2) no bedrock exposures are visible within or adjacent to the crater because of thick regolith coverage, and only small pieces of angular unconsolidated rocks are present on the crater wall and the gently-sloped crater rim, suggesting recent energetic formation of the crater; (3) most samples collected from the crater have identical lithology and petrographic characteristics with the background terrain, but some crater samples contain more abundant clasts and silicate hydrothermal veins, indicating that rocks from depths have been exposed by the crater; (4) no shock metamorphic features were found in the samples after thin section examinations; and (5) a systematic sample survey and iron detector scan within and outside of the crater found no iron-rich meteorites larger than 2 cm in size in a depth of 30 cm. Although no conclusive evidence for an impact origin is found yet, Hailar crater was most likely formed by an impact based on its unique occurrence and comparative geomorphologic study. We suggest that drilling in the crater center is required to verify the impact origin, where hypothesized melt-bearing impactites may be encountered.

  3. Wrinkle Ridges and Young Fresh Crater

    Science.gov (United States)

    2002-01-01

    (Released 10 May 2002) The Science Wrinkle ridges are a very common landform on Mars, Mercury, Venus, and the Moon. These ridges are linear to arcuate asymmetric topographic highs commonly found on smooth plains. The origin of wrinkle ridges is not certain and two leading hypotheses have been put forth by scientists over the past 40 years. The volcanic model calls for the extrusion of high viscosity lavas along linear conduits. This thick lava accumulated over these conduits and formed the ridges. The other model is tectonic and advocates that the ridges are formed by compressional faulting and folding. Today's THEMIS image is of the ridged plains of Lunae Planum located between Kasei Valles and Valles Marineris in the northern hemisphere of the planet. Wrinkle ridges are found mostly along the eastern side of the image. The broadest wrinkle ridges in this image are up to 2 km wide. A 3 km diameter young fresh crater is located near the bottom of the image. The crater's ejecta blanket is also clearly seen surrounding the sharp well-defined crater rim. These features are indicative of a very young crater that has not been subjected to erosional processes. The Story The great thing about the solar system is that planets are both alike and different. They're all foreign enough to be mysterious and intriguing, and yet familiar enough to be seen as planetary 'cousins.' By comparing them, we can learn a lot about how planets form and then evolve geologically over time. Crinkled over smooth plains, the long, wavy raised landforms seen here are called 'wrinkle ridges,' and they've been found on Mars, Mercury, Venus, and the Moon - that is, on rocky bodies that are a part of our inner solar system. We know from this observation that planets (and large-enough moons) follow similar processes. What we don't know for sure is HOW these processes work. Scientists have been trying to understand how wrinkle ridges form for 40 years, and they still haven't reached a conclusion. That

  4. SAGE III Meteor-3M L2 Lunar Event Species Profiles (HDF-EOS) V003

    Data.gov (United States)

    National Aeronautics and Space Administration — SAGE III Meteor-3M L2 Lunar Event Species Profiles are Level 2 data files containing all the species products for a single lunar event. The Stratospheric Aerosol and...

  5. SAGE III Meteor-3M L2 Monthly Cloud Presence Data (HDF-EOS) V003

    Data.gov (United States)

    National Aeronautics and Space Administration — SAGE III Meteor-3M L2 Monthly Cloud Presence Data are monthly data files coincident with solar event granules that provides information about cloud presence during...

  6. SAGE III Meteor-3M L2 Solar Event Species Profiles (HDF-EOS) V004

    Data.gov (United States)

    National Aeronautics and Space Administration — SAGE III Meteor-3M L2 Solar Event Species Profiles are Level 2 data files containing all the species products for a single solar event. The Stratospheric Aerosol and...

  7. SAGE III Meteor-3M L2 Solar Event Species Profiles (Native) V004

    Data.gov (United States)

    National Aeronautics and Space Administration — SAGE III Meteor-3M L2 Solar Event Species Profiles are Level 2 data files containing all the species products for a single solar event. The Stratospheric Aerosol and...

  8. TOMS Meteor-3 Ground Station Overpass Data V008 (TOMSM3OVP) at GES DISC

    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...

  9. SAGE III Meteor-3M L2 Monthly Cloud Presence Data (Native) V003

    Data.gov (United States)

    National Aeronautics and Space Administration — SAGE III Meteor-3M L2 Monthly Cloud Presence Data are monthly data files coincident with solar event granules that provides information about cloud presence during...

  10. Study on meteoric particle destruction when passing through the Earth, Mars and Venus atmospheres

    International Nuclear Information System (INIS)

    Apshtejn, Eh.Z.; Pilyugin, N.N.; Vartanyan, N.V.

    1982-01-01

    A problem of a meteoric particle motion with provision for its nonstationary heating up and change of a form due to evaporation in rarefied layers of the Earth, Mars and Venus atmospheres is investigated. Numerical calculations are performed for a series of stone particles with sizes of approximately 1 mm at initial inlet velocity of 15 km/s 0 <= 60 km/s and inlet angles of 10-90 deg. The particle mass carrying away, temperature of particles, luminescence intensity, and meteoric trace electron concentration in successive time periods during the motion along the trajectory are determined. A comparison of the physical theory of met rites with the known approximate solutions and observations is conducted for the Earth atmosphere. Some peculiarities of meteoric particle destruction in different atmospheres are pointed out. Some methods of atmospheric parameter recovery according to observations of meteoric particle motion are proposed on the base of calculated dependences

  11. Meteor Shower Forecast Improvements from a Survey of All-Sky Network Observations

    Science.gov (United States)

    Moorhead, Althea V.; Sugar, Glenn; Brown, Peter G.; Cooke, William J.

    2015-01-01

    Meteoroid impacts are capable of damaging spacecraft and potentially ending missions. In order to help spacecraft programs mitigate these risks, NASA's Meteoroid Environment Office (MEO) monitors and predicts meteoroid activity. Temporal variations in near-Earth space are described by the MEO's annual meteor shower forecast, which is based on both past shower activity and model predictions. The MEO and the University of Western Ontario operate sister networks of all-sky meteor cameras. These networks have been in operation for more than 7 years and have computed more than 20,000 meteor orbits. Using these data, we conduct a survey of meteor shower activity in the "fireball" size regime using DBSCAN. For each shower detected in our survey, we compute the date of peak activity and characterize the growth and decay of the shower's activity before and after the peak. These parameters are then incorporated into the annual forecast for an improved treatment of annual activity.

  12. SAGE III Meteor-3M L1B Solar Event Transmission Data (Native) V004

    Data.gov (United States)

    National Aeronautics and Space Administration — SAGE III Meteor-3M L1B Solar Event Transmission Data are Level 1B pixel group transmission profiles for a single solar event. The Stratospheric Aerosol and Gas...

  13. Identification of Emission Lines in a Meteor Spectrum Obtained on August 2, 2011

    Czech Academy of Sciences Publication Activity Database

    Mozgova, A.M.; Borovička, Jiří; Spurný, Pavel; Churyumov, K. I.

    2015-01-01

    Roč. 28, č. 2 (2015), s. 289-292 ISSN 1810-4215 Institutional support: RVO:67985815 Keywords : meteor s * spectra * line identification Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics

  14. Nucleation of nitric acid hydrates in polar stratospheric clouds by meteoric material

    Science.gov (United States)

    James, Alexander D.; Brooke, James S. A.; Mangan, Thomas P.; Whale, Thomas F.; Plane, John M. C.; Murray, Benjamin J.

    2018-04-01

    Heterogeneous nucleation of crystalline nitric acid hydrates in polar stratospheric clouds (PSCs) enhances ozone depletion. However, the identity and mode of action of the particles responsible for nucleation remains unknown. It has been suggested that meteoric material may trigger nucleation of nitric acid trihydrate (NAT, or other nitric acid phases), but this has never been quantitatively demonstrated in the laboratory. Meteoric material is present in two forms in the stratosphere: smoke that results from the ablation and re-condensation of vapours, and fragments that result from the break-up of meteoroids entering the atmosphere. Here we show that analogues of both materials have a capacity to nucleate nitric acid hydrates. In combination with estimates from a global model of the amount of meteoric smoke and fragments in the polar stratosphere we show that meteoric material probably accounts for NAT observations in early season polar stratospheric clouds in the absence of water ice.

  15. SAGE III Meteor-3M L2 Lunar Event Species Profiles (Native) V003

    Data.gov (United States)

    National Aeronautics and Space Administration — SAGE III Meteor-3M L2 Lunar Event Species Profiles are Level 2 data files containing all the species products for a single lunar event. The Stratospheric Aerosol and...

  16. Heavy Cratering near Callisto's South Pole

    Science.gov (United States)

    1997-01-01

    Images from NASA's Galileo spacecraft provide new insights into this region near Callisto's south pole. This two frame mosaic shows a heavily cratered surface with smooth plains in the areas between craters. North is to the top of the image. The smoothness of the plains appears to increase toward the south pole, approximately 480 kilometers (293 miles) south of the bottom of the image. This smoothness of Callisto's surface was not evident in images taken during the 1979 flyby of NASA's Voyager spacecraft because the resolution was insufficient to show the effect. This smooth surface, and the process(es) that cause it, are among the most intriguing aspects of Callisto. Although not fully understood, the process(es) responsible for this smoothing could include erosion by tiny meteorites and energetic ions. Some craters, such as Keelut, the 47 kilometer (29 mile) crater in the lower right corner, have sharp, well defined rims. Keelut contains an inner ring surrounding a central depression about 17 kilometers (11 miles) in diameter. Keelut, and the more irregularly shaped, degraded Reginleif, the 32 kilometer (19.5 mile) crater in the top center of the image, are very shallow and have flat floors. Crater forms can be seen down to less than 2 kilometers (1.2 miles) in diameter in the image. Each picture element (pixel) in this image is approximately 0.68 kilometers (0.41 miles) across.This image which was taken by the Galileo spacecraft's solid state imaging (CCD) system during its eighth orbit around Jupiter, on May 6th, 1997. The center of the image is located at 71.3 degrees south latitude, 97.6 degrees west longitude, and was taken when the spacecraft was approximately 35,470 kilometers (21,637 miles) from Callisto.The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC.This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http

  17. On the influence of neutral turbulence on ambipolar diffusivities deduced from meteor trail expansion

    Directory of Open Access Journals (Sweden)

    C. M. Hall

    Full Text Available By measuring fading times of radar echoes from underdense meteor trails, it is possible to deduce the ambipolar diffusivities of the ions responsible for these radar echoes. It could be anticipated that these diffusivities increase monotonically with height akin to neutral viscosity. In practice, this is not always the case. Here, we investigate the capability of neutral turbulence to affect the meteor trail diffusion rate.

    Key words. Meteorology and atmospheric dynamics (middle atmosphere dynamics; turbulence

  18. The Effect of Major Meteor Streams on the Total Ozone in the Earth's Atmosphere

    Science.gov (United States)

    Gorbanev, Yu. M.; Stogneeva, I. A.; Shestopalov, V. A.; Knyazkova, E. F.; Kimakovskaya, I. I.; Kimakovskay, S. R.; Golubaev, A. V.

    The correlation between the total ozone and activity of major meteor streams, such as the Perseids, Geminids, Leonids and Orionids, has been found using the Total Ozone Mapping Spectrometer (TOMS) measurements of the global ozone distribution over the periods 1978 - 1993 and 1996 - 2001. The autocorrelation analysis of the total ozone time series for the period of about 20 years has confirmed the existence of regular changes in the ozone levels at the peaks of meteor shower activity. It has been established that TO decreases after the dates of peak activity of meteor streams (e.g. the Perseids) or during the whole periods of meteor shower activity (e.g. the Geminids, Orionids and Leonids). The analysis of the total ozone distribution (in the Southern and Northern Hemispheres), as well as the local distribution of ozone (over the selected surface area of several hundred square kilometres), was performed during the Leonid meteor shower in 1999. The atmospheric zones for which the ozone distribution pattern can be described as a result of interaction between the meteor shower material and the ozone layer were localised by applying the TOMS data. Such zones correspond to the regions where the highest Leonid activity has been observed. According to the radar observations (conducted in Kazan, Russian Federation), three activity maxima of the 1988 Geminid shower were reported: on the nights of 7th, 12th and 14th December, 1988. The TO decrease was observed on the same dates. Thus, the analysis of the TO changes during the periods of intense meteor shower's activity enables to preliminary assess the maximum overall decline in the total ozone concentration which makes about 5 DU over two weeks. From the results obtained it can be inferred that the ozone layer can be used as an indicator of the interaction between the meteoric material and the Earth's atmosphere.

  19. Results of the IMO Video Meteor Network - June 2017, and effective collection area study

    Science.gov (United States)

    Molau, Sirko; Crivello, Stefano; Goncalves, Rui; Saraiva, Carlos; Stomeo, Enrico; Kac, Javor

    2017-12-01

    Over 18000 meteors were recorded by the IMO Video Meteor Network cameras during more than 7100 hours of observing time during 2017 June. The June Bootids were not detectable this year. Nearly 50 Daytime Arietids were recorded in 2017, and a first flux density profile for this shower in the optical domain is calculated, using video data from the period 2011-2017. Effective collection area of video cameras is discussed in more detail.

  20. On the change of the density of meteoric streams due to planetary disturbances

    International Nuclear Information System (INIS)

    Emel'yanenko, V.V.

    1985-01-01

    The method of estimation for the change of the local spatial density of meteor streams due to planetary perturbations is worked out. An evolution of the density of some meteoric streams along their orbits is studied by taking into consideration the perturbations of Jupiter. It is shown that either decrease or considerable temporary increase of the local density caused by planetary perturbantions is possible. The examples of stable periodic variations of the stream's density are given

  1. 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.)

  2. Double station observation of Draconid meteor outburst from two moving aircraft

    Czech Academy of Sciences Publication Activity Database

    Koten, Pavel; Vaubaillon, J.; Margonis, A.; Toth, J.; Ďuriš, F.; McAulliffe, J.; Oberst, J.

    2015-01-01

    Roč. 118, December (2015), s. 112-119 ISSN 0032-0633 R&D Projects: GA ČR GA14-25251S; GA ČR(CZ) GAP209/11/1382; GA MŠk 7AMB13FR006 Institutional support: RVO:67985815 Keywords : meteor s * meteor showers * Draconids Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 1.942, year: 2015

  3. On the influence of neutral turbulence on ambipolar diffusivities deduced from meteor trail expansion

    Directory of Open Access Journals (Sweden)

    C. M. Hall

    2002-11-01

    Full Text Available By measuring fading times of radar echoes from underdense meteor trails, it is possible to deduce the ambipolar diffusivities of the ions responsible for these radar echoes. It could be anticipated that these diffusivities increase monotonically with height akin to neutral viscosity. In practice, this is not always the case. Here, we investigate the capability of neutral turbulence to affect the meteor trail diffusion rate.Key words. Meteorology and atmospheric dynamics (middle atmosphere dynamics; turbulence

  4. Dependences of Ratio of the Luminosity to Ionization on Velocity and Chemical Composition of Meteors

    Science.gov (United States)

    Narziev, M.

    2011-01-01

    On the bases of results simultaneous photographic and radio echo observations, the results complex radar and television observations of meteors and also results of laboratory modeling of processes of a luminescence and ionization, correlation between of luminous intensity Ip to linear electronic density q from of velocities and chemical structure are investigated. It is received that by increasing value of velocities of meteors and decrease of nuclear weight of substance of particles, lg Ip/q decreased more than one order.

  5. Observations of Leonid Meteors Using a Mid-Wave Infrared Imaging Spectrograph

    Science.gov (United States)

    Rossano, George S.; Russell, Ray W.; Lynch, David K.; Tessensohn, Ted K.; Warren, David; Jenniskens, Peter

    We report broadband 3-5.5 µm detections of two Leonid meteors observed during the 1998 Leonid Multi-Instrument Aircraft Campaign. Each meteor was detected at only one position along their trajectory just prior to the point of maximum light emission. We describe the particular aspects of the Aerospace Corp. Mid-wave Infra-Red Imaging Spectrograph (MIRIS) developed for the observation of short duration transient events that impact its ability to detect Leonid meteors. This instrument had its first deployment during the 1998 Leonid MAC. We infer from our observations that the mid-wave IR light curves of two Leonid meteors differed from the visible light curve. At the points of detection, the infrared emission in the MIRIS passband was 25 +/- 4 times that at optical wavelengths for both meteors. In addition, we find an upper limit of 800 K for the solid body temperature of the brighter meteor we observed, at the point in the trajectory where we made our mid-wave IR detection.

  6. A first report on meteor-generated seismic signals as detected by the SANSN

    Directory of Open Access Journals (Sweden)

    Frederick Roelofse

    2013-05-01

    Full Text Available A bright meteor with an apparent magnitude of -18 was seen over large parts of southern Africa at ~23:00 South African Standard Time on 21 November 2009. Here we discuss the eye-witness accounts related to the meteor as well as the seismic signals generated by the meteor's passage through the atmosphere as detected by the Mussina seismograph station forming part of the South African National Seismograph Network. Two signals were identified on the seismogram; the first arrival is interpreted as a precursor coupled seismic wave and the second, which arrived ~138 s after the first, as a directly coupled airwave. The meteor is thought to have entered the atmosphere close to Mussina shortly before 22:55.06 local time, from where it proceeded in a westerly to northwesterly direction with an elevation angle not exceeding 43°. Our results presented here dispel the beliefs of many observers who thought that the meteor must have made landfall very close to their localities. In addition, this contribution documents the first instance of meteor-related seismic signals recorded by the South African National Seismograph Network.

  7. Variation of sporadic meteor activity during the 23. cycle of solar activity

    International Nuclear Information System (INIS)

    Porubcan, V.; Zigo, P.; Cevolani, G.; Rozboril, J.; Pupillo, G.

    2009-01-01

    Analyses of the influence of solar activity on sporadic meteor counts based on visual and radar meteor observations present rather contradictory results, indicating a possible variation of the sporadic meteor counts with a solar activity, with the maximum in observed meteor rates occurring from zero up to about five years after the solar activity maximum. With this perspective, in the present paper observations of the sporadic meteor background, obtained by a forward-scatter radio system for meteor observation operating along the Bologna (Italy)-Modra (Slovakia) baseline in 1996-2007, are analysed and discussed. The activity curves of all echoes and their variations indicate a correlation with solar activity in the 23. solar cycle represented by the solar relative number R (corr. coef. 0.71), as well as with the solar coronal index C1 (corr. coef. 0.73). The mass distribution exponent s and its variations (with corr. coef. against R and C1, 0.12 and 0.25, respectively) does not show a correlation consistent with solar activity and, from the viewpoint of s, suggest the existence of a relatively stable population of sporadic background meteoroids in the surroundings of the Earth's orbit during the investigated period.

  8. An investigation of the structure of the southern hemisphere radio-meteor streams

    International Nuclear Information System (INIS)

    Roux, D.G.

    1988-01-01

    Current knowledge of the Solar System, with a particular emphasis on the systems of interplanetary objects, is reviewed, and the theory of meteors and the reflection of radio waves from meteoric ionization is then discussed. A description of the meteor radar is given and a method of calibrating the antenna beam is developed. The main project comprises two parts: A general survey of the radar echo-rate for 20 major and minor meteor streams and the sporadic meteor background, conducted from Grahamstown over the period 1986 April to 1988 January, is described. Definite shower activity was observed for all of the major and some of the minor showers. A method of recovering meteor radiant distributions from the distribution of echo direction was developed. A technique of compensating for possible distortions of the resulting radiant maps, which may arise due to the anisotropic antenna beam was devised. This involved a system of echo-weighting. Radiant maps which showed considerably less distortion were obtained without the weighting procedure. It is concluded that, although the method in its present form introduces spurious features into the maps, the principle is sound and should eventually be refined to produce the desired compensation. 71 refs., 165 figs., 2 tabs

  9. Geological Mapping of Lunar Crater Lalande: Topographic Configuration, Morphology and Cratering Process

    Science.gov (United States)

    Li, B.; Ling, Z. C.; Zhang, J.; Chen, J.; Liu, C. Q.; Bi, X. Y.

    2017-07-01

    Highland crater Lalande (4.45° S, 8.63° W; D = 23.4 km) is located on the PKT area of the lunar near side, southeast of Mare Insularum. It is a complex crater in Copernican era and has three distinguishing features: high silicic anomaly, highest Th abundance and special landforms on its floor. There are some low-relief bulges on the left of crater floor with regular circle or ellipse shapes. They are  250 to 680 m wide and  30 to 91 m high with maximum flank slopes > 20°. There are two possible scenarios for the formation of these low-relief bulges which are impact melt products or young silicic volcanic eruptions. According to the absolute model ages of ejecta, melt ponds and hummocky floor, the ratio of diameter and depth, similar bugle features within other Copernican-aged craters and lack of volcanic source vents, we hypothesized that these low-relief bulges were most consistent with an origin of impact melts during the crater formation instead of small and young volcanic activities occurring on the crater floor. Based on Kaguya TC ortho-mosaic and DTM data produced by TC imagery in stereo, geological units and some linear features on the floor and wall of Lalande have been mapped. Eight geological units are organized by crater floor units: hummocky floor, central peak and low-relief bulges; and crater wall units: terraced walls, channeled and veneered walls, interior walls, mass wasting areas, blocky areas, and melt ponds. These geological units and linear features at Lalande provided us a chance to understand some details of the cratering process and elevation differences on the floor. We evaluated several possibilities to understand the potential causes for the observed elevation differences on the Lalande's floor. We proposed that late-stage wall collapse and subsidence due to melt cooling could be the possible causes of observed elevation differences on the floor.

  10. Aqueous alteration detection in Tikhonravov crater, Mars

    Science.gov (United States)

    Mancarella, F.; Fonti, S.; Alemanno, G.; Orofino, V.; Blanco, A.

    2018-03-01

    The existence of a wet period lasting long enough to allow the development of elementary forms of life on Mars has always been a very interesting issue. Given this perspective, the research for geological markers of such occurrences has been continually pursued. Once a favorable site is detected, effort should be spent to get as much information as possible aimed at a precise assessment of the genesis and evolution of the areas showing the selected markers. In this work, we discuss the recent finding of possible deposits pointing to the past existence of liquid water in Tikhonravov crater located in Arabia Terra. Comparison of CRISM spectra and those of laboratory minerals formed by aqueous alteration has led us to the conclusion that the studied areas within the impact crater host phyllosilicates deposits. In addition, analysis of the CRISM spectra has resulted in the tentative identification of carbonates mixed with phyllosilicates.

  11. Spectral Clustering of Hermean craters hollows

    Science.gov (United States)

    Lucchetti, Alice; Pajola, Maurizio; Cremonese, Gabriele; Carli, Cristian; Marzo, Giuseppe; Roush, Ted

    2017-04-01

    The Mercury Dual Imaging System (MDIS, Hawkins et al., 2007) onboard NASA MESSENGER (MErcury Surface, Space ENvironment, GEochemistry, and Ranging) spacecraft, provided high-resolution images of "hollows", i.e. shallow, irregular, rimless, flat-floored depressions with bright interiors and halos, often found on crater walls, rims, floors and central peaks (Blewett et al., 2011, 2013). The formation mechanism of these features was suggested to be related to the depletion of subsurface volatiles (Blewett et al., 2011, Vaughan et al., 2012). To understand the hollows' mineralogical composition, which can provide new insights on Mercury's surface characterization, we applied a spectral clustering method to different craters where hollows are present. We chose, as first test case, the 20 km wide Dominici crater due to previous multiple spectral detection (Vilas et al., 2016). We used the MDIS WAC dataset covering Dominici crater with a scale of 935 m/pixel through eight filters, ranging from 0.433 to 0.996 μm. First, the images have been photometrically corrected using the Hapke parameters (Hapke et al., 2002) derived in Domingue et al. (2015). We then applied a statistical clustering over the entire dataset based on a K-means partitioning algorithm (Marzo et al., 2006). This approach was developed and evaluated by Marzo et al. (2006, 2008, 2009) and makes use of the Calinski and Harabasz criterion (Calinski, T., Harabasz, J., 1974) to identify the intrinsically natural number of clusters, making the process unsupervised. The natural number of ten clusters was identified and spectrally separates the Dominici surrounding terrains from its interior, as well as the two hollows from their edges. The units located on the brightest part of the south wall/rim of Dominici crater clearly present a wide absorption band between 0.558 and 0.828 μm. Hollows surrounding terrains typically present a red slope in the VNIR with a possible weak absorption band centered at 0.748

  12. Asymmetric Space Weathering on Lunar Crater Walls

    Science.gov (United States)

    Sim, Chae Kyung; Kim, Sungsoo S.; Lucey, Paul G.; Garrick-Bethell, Ian; Choi, Young-Jun

    2017-11-01

    Using new topography-corrected spectral data from the SELENE spacecraft, here we report a new lunar crater property produced by space weathering. We find that the optical properties of north, south, east, and west walls vary systematically across the Moon; pole-facing walls are brighter and less red (i.e., less mature) than their equator-facing counterparts as latitude increases, which we explain by reduced solar wind flux in pole-facing slopes. On the nearside, we find that east-west differences in crater wall brightness and redness vary with longitude, which we explain by solar wind shielding as the Moon passes through the Earth's magnetosphere. Because micrometeoroids are largely unaffected by magnetosphere passage, the longitudinal effect is used to discriminate between micrometeoroid and solar wind effects. Thus, for the first time we quantify how surface optical properties vary with solar wind flux.

  13. Rochechouart meteorite crater - Identification of projectile

    Science.gov (United States)

    Janssens, M.-J.; Hertogen, J.; Takahashi, H.; Anders, E.; Lambert, P.

    1977-01-01

    Ten samples from the 20-km Rochechouart crater in France have been analyzed for the siderophile elements Ir, Os, Re, Au, Pd, Ni, and Ge by radiochemical neutron activation analysis. The up to 1000-fold enrichment of siderophiles correlates with shock effects, increasing in the following order from least to greatest: basement rocks, glass-free breccias, glassy breccias, impact melts. The abundance pattern of the meteorite was determined from interelement correlations. Several samples fell off the correlation lines, presumably due to recrystallization and weathering of impact glasses during the approximately 165-m.y. age of the crater. The most reliable diagnostic elements were Os, Ir, Ni, and Pd; their abundance ratios suggest that the Rochechouart meteorite was a IIA iron.

  14. Low-velocity impact cratering experiments in granular slopes

    Science.gov (United States)

    Hayashi, Kosuke; Sumita, Ikuro

    2017-07-01

    Low-velocity impact cratering experiments are conducted in sloped granular targets to study the effect of the slope angle θ on the crater shape and its scales. We use two types of granular matter, sand and glass beads, former of which has a larger friction coefficient μs = tanθr , where θr is the angle of repose. Experiments show that as θ increases, the crater becomes shallower and elongated in the direction of the slope. Furthermore the crater floor steepens in the upslope side and a thick rim forms in the downslope side, thus forming an asymmetric profile. High-speed images show that these features are results of ejecta being dispersed farther towards the downslope side and the subsequent avalanche which buries much of the crater floor. Such asymmetric ejecta dispersal can be explained by combining the Z-model and a ballistic model. Using the topographic maps of the craters, we classify crater shape regimes I-III, which transition with increasing θ : a full-rim crater (I), a broken-rim crater (II), and a depression (III). The critical θ for the regime transitions are larger for sand compared to glass beads, but collapse to close values when we use a normalized slope θ^ = tanθ / tanθr . Similarly we derive θ^-dependences of the scaled crater depth, length, width and their ratios which collapse the results for different targets and impact energies. We compare the crater profiles formed in our experiments with deep craters on asteroid Vesta and find that some of the scaled profiles nearly overlap and many have similar depth / length ratios. This suggests that these Vestan craters may also have formed in the gravity regime and that the formation process can be approximated by a granular flow with a similar effective friction coefficient.

  15. Structural and Geological Interpretation of Posidonius Crater on the Moon

    Science.gov (United States)

    Ishihara, Y.; Chiba, T.; Haruyama, J.; Otake, H.; Ohtake, M.

    2015-12-01

    Posidonius crater locates on northeastern rim parts of the Serenitatis basin and is a typical floor-fractured crater. Because of Posidonius is located lunar central nearside and easily observed by ground-base telescope, the complex texture of crater floor attracted planetary scientist attention from before lunar exportation era. However, origin or formation histories of floor fractures are not fully resolved yet. In this study, we try to estimate geologic histories of Posidonius crater based on topographic data and multiband image data obtained by Terrain Camera (TC) and Multiband Imager (MI) onboard Kaguya. A part of crater floor of Posidonius is flooded by mare basalt. Previous studies interpreted that the source of mare basalt is located somewhere at Mare Serenitatis and flooded into Posidonius crater, then sinuous rill (Rimae Posidonius) is the resulting structure of flooded basalt flow. However, based on TC topographic data, sinuous rill feature indicate opposite flow direction to previous interpretations. Based on TC topographic data, we could interpret topographic features as follows; Rimare Posidonius flow from volcanic vent located at northern edge of Posidonius crater floor and flow out to Mare Serenitatis at western rim, the central part of crater floor slightly leaned to west and broken in several regions. From band depth of MI data, eastern part of crater floor is mostly consisted by highland materials and complex rills are basically not showing the basaltic feature. Combined both analysis results, we interpret the cause of complex structure of Posidonius crater is as follows; after crater formation, large sill intruded below crater floor and uppermost layer of crater floor is delaminated from the basement then floats on basaltic intrusion as "otoshibuta" (Japanese style lid for stew). Complex fracture was probably formed delamination and flotation stage by mechanical stress.

  16. The central uplift of Ritchey crater, Mars

    Science.gov (United States)

    Ding, Ning; Bray, Veronica J.; McEwen, Alfred S.; Mattson, Sarah S.; Okubo, Chris H.; Chojnacki, Matthew; Tornabene, Livio L.

    2015-01-01

    Ritchey crater is a ∼79 km diameter complex crater near the boundary between Hesperian ridged plains and Noachian highland terrain on Mars (28.8°S, 309.0°E) that formed after the Noachian. High Resolution Imaging Science Experiment (HiRISE) images of the central peak reveal fractured massive bedrock and megabreccia with large clasts. Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) spectral analysis reveals low calcium pyroxene (LCP), olivine (OL), hydrated silicates (phyllosilicates) and a possible identification of plagioclase bedrock. We mapped the Ritchey crater central uplift into ten units, with 4 main groups from oldest and originally deepest to youngest: (1) megabreccia with large clasts rich in LCP and OL, and with alteration to phyllosilicates; (2) massive bedrock with bright and dark regions rich in LCP or OL, respectively; (3) LCP and OL-rich impactites draped over the central uplift; and (4) aeolian deposits. We interpret the primitive martian crust as igneous rocks rich in LCP, OL, and probably plagioclase, as previously observed in eastern Valles Marineris. We do not observe high-calcium pyroxene (HCP) rich bedrock as seen in Argyre or western Valles Marineris. The association of phyllosilicates with deep megabreccia could be from impact-induced alteration, either as a result of the Richey impact, or alteration of pre-existing impactites from Argyre basin and other large impacts that preceded the Ritchey impact, or both.

  17. The isostatic state of Mead crater

    Science.gov (United States)

    Banerdt, W. B.; Konopliv, A. S.; Rappaport, N. J.; Sjogren, W. L.; Grimm, R. E.; Ford, P. G.

    1994-01-01

    We have analyzed high-resolution Magellan Doppler tracking data over Mead crater, using both line-of-sight and spherical harmonic methods, and have found a negative gravity anomaly of about 4-5 mgal (at spacecraft altitude, 182 km). This is consistent with no isostatic compensation of the present topography; the uncertainty in the analysis allows perhaps as much as 30% compensation at shallow dpeths (approximately 25 km). This is similar to observations of large craters on Earth, which are not generally compensated, but contrasts with at least some lunar basins which are inferred to have large Moho uplifts and corresponding positive Bouguer anomalies. An uncompensated load of this size requires a lithosphere with an effective elastic lithosphere thickness greater than 30 km. In order for the crust-mantle boundary not to have participated in the deformation associated with the collapse of the transient cavity during the creation of the crater, the yield strength near the top of the mantle must have been significantly higher on Earth and Venus than on the Moon at the time of basin formation. This might be due to increased strength against frictional sliding at the higher confining pressures within the larger planets. Alternatively, the thinner crusts of Earth and Venus compared to that of the Moon may result in higher creep strength of the upper mantle at shallower depths.

  18. Mesospheric winds measurements using three meteor radars in Brazil

    Science.gov (United States)

    Batista, Paulo; Clemesha, Barclay; Fátima Andrioli, Vânia; Paulino, Ana Roberta; Buriti, Ricardo; Schuch, Nelson Jorge

    Three meteor radars of the SkiYmet type have been installed in Brazil covering low, tropical and sub-tropical latitudes. The first at Cachoeira Paulista(22.7 S, 45.0 W) started in march 1999, the second at Cariri(7.4 S, 36.5 W) in May, 2005, and the last one at Santa Maria( 29.7 S, 53.8 W) in December, 2005. Coincident periods of measurements permitted the determination of the Mean Winds, Planetary Waves, Tides and Gravity Wave Variances for these different latitudes and their comparison. Amplitude and phase structures are similar for Cachoeira Paulista and Santa Maria, but differ from the near-equatorial site Cariri. Also the Lunar Semidiurnal Tides have been studied at the three sites for the period January 2005 to December 2008. Amplitudes between 1 and 8 m/s were determined with the meridional winds being larger than the zonal in the three sites. Wind measurements have been used also as subsidiary data in the studies involving the sodium layer and the mesospheric airglow though lidar, photometers and imagers.

  19. Low latitude southern hemisphere mesospheric dynamics from meteor radars measurements

    Science.gov (United States)

    Batista, Paulo; Schuch, Nelson Jorge; Clemesha, Barclay; Buriti, Ricardo; Paulino, Ana Roberta; Guharay, Amitava; Andrioli, Vania Fatima

    Three meteor radars of the SkiYmet type have been installed in Brazil covering low, tropical and sub-tropical latitudes. The first at Cachoeira Paulista(22.7° S, 45.0° W) started in march 1999, the second at Cariri(7.4° S, 36.5° W) in May, 2005, and the last one at Santa Maria( 29.7° S, 53.8° W) in December, 2005. Data obtained in coincident periods of measurements permitted the determination of the Mean Winds, Planetary Waves, Tides and Gravity Wave Variances for these different latitudes and the comparison of them. Amplitude and phase structures are similar for Cachoeira Paulista and Santa Maria, but differ from the near-equatorial site Cariri. Also the Lunar Semidiurnal Tides have been studied at the three sites for the period January 2005 to December 2008. Amplitudes between 1 and 8 m/s were determined with the meridional winds being larger than the zonal in the three sites. It is found that northern hemisphere SSW’s affect the QTDW , and the Solar and Lunar tides at southern low latitudes but the 2002 southern hemisphere major SSW had a small effect in tropical MLT. Wind measurements have also been used to study Kelvin waves, terdiurnal Tide and QTDW variability. In this presentation we summarize the main results obtained.

  20. Novel Experimental Simulations of the Atmospheric Injection of Meteoric Metals

    Energy Technology Data Exchange (ETDEWEB)

    Gómez Martín, J. C.; Bones, D. L.; Carrillo-Sánchez, J. D.; James, A. D.; Plane, J. M. C. [School of Chemistry, University of Leeds, Woodhouse Lane, Leeds LS2 9JT (United Kingdom); Trigo-Rodríguez, J. M. [Meteorites, Minor Bodies and Planetary Science Group, Institute of Space Sciences (CSIC-IEEC). Campus UAB, C/Can Magrans s/n, E-08193 Cerdanyola del Vallés (Barcelona) (Spain); Fegley, B. Jr., E-mail: J.M.C.Plane@leeds.ac.uk [Washington University, St. Louis, MO (United States)

    2017-02-20

    A newly developed laboratory, Meteoric Ablation Simulator (MASI), is used to test model predictions of the atmospheric ablation of interplanetary dust particles (IDPs) with experimental Na, Fe, and Ca vaporization profiles. MASI is the first laboratory setup capable of performing time-resolved atmospheric ablation simulations, by means of precision resistive heating and atomic laser-induced fluorescence detection. Experiments using meteoritic IDP analogues show that at least three mineral phases (Na-rich plagioclase, metal sulfide, and Mg-rich silicate) are required to explain the observed appearance temperatures of the vaporized elements. Low melting temperatures of Na-rich plagioclase and metal sulfide, compared to silicate grains, preclude equilibration of all the elemental constituents in a single melt. The phase-change process of distinct mineral components determines the way in which Na and Fe evaporate. Ca evaporation is dependent on particle size and on the initial composition of the molten silicate. Measured vaporized fractions of Na, Fe, and Ca as a function of particle size and speed confirm differential ablation (i.e., the most volatile elements such as Na ablate first, followed by the main constituents Fe, Mg, and Si, and finally the most refractory elements such as Ca). The Chemical Ablation Model (CABMOD) provides a reasonable approximation to this effect based on chemical fractionation of a molten silicate in thermodynamic equilibrium, even though the compositional and geometric description of IDPs is simplistic. Improvements in the model are required in order to better reproduce the specific shape of the elemental ablation profiles.

  1. 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.

  2. Computational Modeling of Meteor-Generated Ground Pressure Signatures

    Science.gov (United States)

    Nemec, Marian; Aftosmis, Michael J.; Brown, Peter G.

    2017-01-01

    We present a thorough validation of a computational approach to predict infrasonic signatures of centimeter-sized meteoroids. We assume that the energy deposition along the meteor trail is dominated by atmospheric drag and simulate the steady, inviscid flow of air in thermochemical equilibrium to compute the meteoroid's near-body pressure signature. This signature is then propagated through a stratified and windy atmosphere to the ground using a methodology adapted from aircraft sonic-boom analysis. An assessment of the numerical accuracy of the near field and the far field solver is presented. The results show that when the source of the signature is the cylindrical Mach-cone, the simulations closely match the observations. The prediction of the shock rise-time, the zero-peak amplitude of the waveform, and the duration of the positive pressure phase are consistently within 10% of the measurements. Uncertainty in the shape of the meteoroid results in a poorer prediction of the trailing part of the waveform. Overall, our results independently verify energy deposition estimates deduced from optical observations.

  3. [Abdominal spasms, meteorism, diarrhea: fructose intolerance, lactose intolerance or IBS?].

    Science.gov (United States)

    Litschauer-Poursadrollah, Margaritha; El-Sayad, Sabine; Wantke, Felix; Fellinger, Christina; Jarisch, Reinhart

    2012-12-01

    Meteorism, abdominal spasms, diarrhea, casually obstipation, flatulence and nausea are symptoms of fructose malabsorption (FIT) and/or lactose intolerance (LIT), but are also symptoms of irritable bowel syndrome (IBS). Therefore these diseases should be considered primarily in patients with digestive complaints. For diagnosis an H(2)-breath test is used.In 1,935 patients (526 m, 1,409 f) a fructose intolerance test and in 1,739 patients (518 m,1,221 f) a lactose intolerance test was done.FIT is found more frequently than LIT (57 versus 52 % in adults (p intolerance (HIT). Headache (ca. 10 %), fatigue (ca. 5 %) and dizziness (ca. 3 %) may occur after the test, irrespective whether the test was positive or negative.In more than 2/3 of patients a diet reduced in fructose or lactose may lead to improvement or remission of these metabolic disorders. IBS, which is often correlated with FIT (183/221 patients = 83 %), can be improved by relevant but also not relevant diets indicating that irritable bowel disease seems to be caused primarily by psychological disorders.

  4. Numerical simulation of turbulent flows over crater-like obstacles: application to Gale crater, landing site of the Curiosity rover

    Science.gov (United States)

    Anderson, W.; Day, M. D.

    2017-12-01

    Mars is a dry planet with a thin atmosphere. Aeolian processes - wind-driven mobilization of sediment and dust - are the dominant mode of landscape variability on the dessicated landscapes of Mars. Craters are common topographic features on the surface of Mars, and many craters on Mars contain a prominent central mound (NASA's Curiosity rover was landed in Gale crater, with the rover journeying across an inner plan and towards Gale's central mound, Aeolus Mons). These mounds are composed of sedimentary fill, and, therefore, they contain rich information on the evolution of climatic conditions on Mars embodied in the stratigraphic "layering" of sediments. Many other craters no longer house a mound, but contain sediment and dust from which dune fields and other features form. Using density-normalized large-eddy simulations, we have modeled turbulent flows over crater-like topographies that feature a central mound. Resultant datasets suggest a deflationary mechanism wherein vortices shed from the upwind crater rim are realigned to conform to the crater profile via stretching and tilting. This insight was gained using three-dimensional datasets (momentum, vorticity, and turbulent stresses) retrieved from LES, and assessment of the relative influence of constituent terms responsible for the sustenance of mean vorticity. The helical, counter-rotating vortices occupy the inner region of the crater, and, therefore, are argued to be of great importance for aeolian morphodynamics in the crater (radial katabatic flows are also important to aeolian processes within the crater).

  5. The Use of D-Criteria to Assess Meteor Shower Significance

    Science.gov (United States)

    Moorhead, Althea V.

    2017-01-01

    In theory, a meteor shower can be distinguished from the sporadic meteor background by its short duration and orbital similarity. In practice, the duration and strength of a shower and the orbital similarity between its constituent meteors varies widely between showers. Further complicating matters is the anisotropy of the sporadic background. These combined factors make it difficult to distinguish between shower and sporadic meteors with a single, static set of criteria. The orbital similarity, or D-, parameters are often used to assess the relationship between meteors [1,2,3]. The more dissimilar two orbits are, the higher their computed D value will be; generally, meteors are considered related if their D-parameter falls below some cutoff value [4]. However, this approach will include some sporadic meteors, and when a weak shower lies near a sporadic source, the false positive rate for shower association can be quite high. Additionally, this cutoff approach does not assess whether the shower itself is significant. We present a method for using D-parameters to extract showers from a dataset that automatically takes shower strength into account and tests for significance [5]. We accomplish this by calculating the false positive rate for shower association using "shower analogs," which are identical to the original shower except in solar longitude. This method is applied to a set of more than 30,000 meteors detected by the NASA All-Sky Fireball Network [6] and the Southern Ontario Meteor Network (SOMN) [7]. We previously detected 29 showers in our data using this method [5]; now, with another year of data, we have several additional detections. Figure 1 presents one example: the 2016 July gamma Draconid outburst. There are several benefits to using our method. First, it provides a test of shower significance (see Fig. 2 for an example of a non-detection). Second, it quantifies the probability that a meteor belongs to a given shower as a function of D

  6. Ten years of METEOR (an international rheumatoid arthritis registry): development, research opportunities and future perspectives.

    Science.gov (United States)

    Bergstra, Sytske Anne; Machado, Pedro M M C; van den Berg, Rosaline; Landewé, Robert B M; Huizinga, Tom W J

    2016-01-01

    Ten years ago, the METEOR tool was developed to simulate treatment-to-target and create an international research database. The development of the METEOR tool and database, research opportunities and future perspectives are described. The METEOR tool is a free, online, internationally available tool in which daily practice visits of all rheumatoid arthritis patients visiting a rheumatologist can be registered. In the tool, disease characteristics, patient- and physician-reported outcomes and prescribed treatment could be entered. These can be subsequently displayed in powerful graphics, facilitating treatment decisions and patient-physician interactions. An upload facility is also available, by which data from local electronic health record systems or registries can be integrated into the METEOR database. This is currently being actively used in, among other countries, the Netherlands, Portugal and India. Since an increasing number of hospitals use electronic health record systems, the upload facility is being actively used by an increasing number of sites, enabling them to benefit from the benchmark and research opportunities of METEOR. Enabling a connection between local registries and METEOR is a well established but time-consuming process for which an IT-specialist of METEOR and the local registry are necessary. However, once this process has been finished, data can be uploaded regularly and relatively easily according to a pre-specified format. The METEOR database currently contains data from >39,000 patients and >200,000 visits, from 32 different countries and is ever increasing. Continuous efforts are being undertaken to increase the quality of data in the database. Since METEOR was founded 10 years ago, many rheumatologists worldwide have used the METEOR tool to follow-up their patients and improve the quality of care they provide to their patients. Combined with uploaded data, this has led to an extensive growth of the database. It now offers a unique

  7. Be2D: A model to understand the distribution of meteoric 10Be in soilscapes

    Science.gov (United States)

    Campforts, Benjamin; Vanacker, Veerle; Vanderborght, Jan; Govers, Gerard

    2016-04-01

    Cosmogenic nuclides have revolutionised our understanding of earth surface process rates. They have become one of the standard tools to quantify soil production by weathering, soil redistribution and erosion. Especially Beryllium-10 has gained much attention due to its long half-live and propensity to be relatively conservative in the landscape. The latter makes 10Be an excellent tool to assess denudation rates over the last 1000 to 100 × 103 years, bridging the anthropogenic and geological time scale. Nevertheless, the mobility of meteoric 10Be in soil systems makes translation of meteoric 10Be inventories into erosion and deposition rates difficult. Here we present a coupled soil hillslope model, Be2D, that is applied to synthetic and real topography to address the following three research questions. (i) What is the influence of vertical meteoric Be10 mobility, caused by chemical mobility, clay translocation and bioturbation, on its lateral redistribution over the soilscape, (ii) How does vertical mobility influence erosion rates and soil residence times inferred from meteoric 10Be inventories and (iii) To what extent can a tracer with a half-life of 1.36 Myr be used to distinguish between natural and human-disturbed soil redistribution rates? The model architecture of Be2D is designed to answer these research questions. Be2D is a dynamic model including physical processes such as soil formation, physical weathering, clay migration, bioturbation, creep, overland flow and tillage erosion. Pathways of meteoric 10Be mobility are simulated using a two step approach which is updated each timestep. First, advective and diffusive mobility of meteoric 10Be is simulated within the soil profile and second, lateral redistribution because of lateral soil fluxes is calculated. The performance and functionality of the model is demonstrated through a number of synthetic and real model runs using existing datasets of meteoric 10Be from case-studies in southeastern US. Brute

  8. An Orbital Meteoroid Stream Survey Using the Southern Argentina Agile Meteor Radar (SAAMER) Based on a Wavelet Approach

    Science.gov (United States)

    Pokorny, P.; Janches, D.; Brown, P. G.; Hormaechea, J. L.

    2017-01-01

    Over a million individually measured meteoroid orbits were collected with the Southern Argentina Agile MEteor Radar (SAAMER) between 2012-2015. This provides a robust statistical database to perform an initial orbital survey of meteor showers in the Southern Hemisphere via the application of a 3D wavelet transform. The method results in a composite year from all 4 years of data, enabling us to obtain an undisturbed year of meteor activity with more than one thousand meteors per day. Our automated meteor shower search methodology identified 58 showers. Of these showers, 24 were associated with previously reported showers from the IAU catalogue while 34 showers are new and not listed in the catalogue. Our searching method combined with our large data sample provides unprecedented accuracy in measuring meteor shower activity and description of shower characteristics in the Southern Hemisphere. Using simple modeling and clustering methods we also propose potential parent bodies for the newly discovered showers.

  9. Morphological Indicators of a Mascon Beneath Ceres's Largest Crater, Kerwan

    Science.gov (United States)

    Bland, M. T.; Ermakov, A. I.; Raymond, C. A.; Williams, D. A.; Bowling, T. J.; Preusker, F.; Park, R. S.; Marchi, S.; Castillo-Rogez, J. C.; Fu, R. R.; Russell, C. T.

    2018-02-01

    Gravity data of Ceres returned by the National Aeronautics and Space Administration's Dawn spacecraft is consistent with a lower density crust of variable thickness overlying a higher density mantle. Crustal thickness variations can affect the long-term, postimpact modification of impact craters on Ceres. Here we show that the unusual morphology of the 280 km diameter crater Kerwan may result from viscous relaxation in an outer layer that thins substantially beneath the crater floor. We propose that such a structure is consistent with either impact-induced uplift of the high-density mantle beneath the crater or from volatile loss during the impact event. In either case, the subsurface structure inferred from the crater morphology is superisostatic, and the mass excess would result in a positive Bouguer anomaly beneath the crater, consistent with the highest-degree gravity data from Dawn. Ceres joins the Moon, Mars, and Mercury in having basin-associated gravity anomalies, although their origin may differ substantially.

  10. A schematic model of crater modification by gravity

    Science.gov (United States)

    Melosh, H. J.

    1982-01-01

    The morphology of craters found on planets and moons of the solar system is examined and a development model which can account for the observed crater characteristics is discussed. The prompt collapse of craters to form flat floors, terraced walls, and central peak structures is considered to be the result of an approximate Bingham plastic rheology of the material surrounding the crater. This rheology is induced dynamically by the strong incoherent acoustic 'noise' accompanying excavation of the crater. Central pits, peak rings, and other multiple symmetric-profile rings originate by oscillation of this fluid. Large craters with transient depths comparable to the lithosphere thickness are subject to collapse by fragmentation of the lithosphere as well as fluidization. The considered concepts are developed mathematically. A model emerges which appears capable of explaining most of the qualitative features of large impact structures.

  11. Structural uplift and ejecta thickness of lunar mare craters: New insights into the formation of complex crater rims

    Science.gov (United States)

    Krüger, Tim; Kenkmann, Thomas

    2015-04-01

    Most complex impact craters on solid planetary surfaces throughout the Solar System exhibit elevated crater rims similar to the elevated crater rims of simple craters. In principal the final elevation of the crater rim is due to the deposition of ejecta on the structurally uplifted bedrock of the pre-impact surface. For simple craters the elevated crater rim is due to two well understood factors: (i) Emplacement of the coherent proximal ejecta material at the transient cavity rim (overturned flap) [1]. (ii) Structural uplift of the pre-impact surface in the proximity of the transient cavity [1, 2]. The amount of structural uplift at the rim of simple craters is due to plastic thickening of the target rock, the emplacement of interthrust wedges and/or the injection of dike material in the underlying target [1, 2, 3, 4]. Both factors, (i) and (ii), are believed to equally contribute to the structural uplift of simple craters. Larger craters have complex morphologies and the crater's extent may considerably exceed that of the transient cavity due to gravity-driven adjustment movements. For instance, the Ries crater's final diameter is twice of its transient cavity size. It is expected that both ejecta thickness and structural uplift decrease with increasing distance from the rim of the transient crater. For lunar craters the continuous ejecta extends up to 2 crater radii from the crater center. The ejecta blanket thickness ET at the rim crest of the transient crater (which is inside the final crater) is a function of the distance r from the crater center, with RT as the radius of the transient crater [2, 6, 7] and is expressed by the following function: (1) ET = 0.033 RT (r/RT)^-3.0 for r ≥ RT [5, 6] The structural uplift is largest at the transient cavity rim and gets rapidly smaller with increasing distance to the crater center and disappears after 1.3 - 1.7 crater radii [1]. These circumstances raise the question, how elevated rims of complex craters form? Based

  12. Roter Kamm Impact Crater in Namibia

    Science.gov (United States)

    1995-01-01

    This space radar image shows the Roter Kamm impact crater in southwest Namibia. The crater rim is seen in the lower center of the image as a radar-bright, circular feature. Geologists believe the crater was formed by a meteorite that collided with Earth approximately 5 million years ago. The data were acquired by the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) instrument onboard space shuttle Endeavour on April 14, 1994. The area is located at 27.8 degrees south latitude and 16.2 degrees east longitude in southern Africa. The colors in this image were obtained using the following radar channels: red represents the L-band (horizontally transmitted and received); green represents the L-band (horizontally transmitted and vertically received); and blue represents the C-band (horizontally transmitted and vertically received). The area shown is approximately 25.5 kilometers (15.8 miles) by 36.4 kilometers (22.5 miles), with north toward the lower right. The bright white irregular feature in the lower left corner is a small hill of exposed rock outcrop. Roter Kamm is a moderate sized impact crater, 2.5 kilometers (1.5 miles) in diameter rim to rim, and is 130 meters (400 feet) deep. However, its original floor is covered by sand deposits at least 100 meters (300 feet) thick. In a conventional aerial photograph, the brightly colored surfaces immediately surrounding the crater cannot be seen because they are covered by sand. The faint blue surfaces adjacent to the rim may indicate the presence of a layer of rocks ejected from the crater during the impact. The darkest areas are thick windblown sand deposits which form dunes and sand sheets. The sand surface is smooth relative to the surrounding granite and limestone rock outcrops and appears dark in radar image. The green tones are related primarily to larger vegetation growing on sand soil, and the reddish tones are associated with thinly mantled limestone outcrops. Studies of impact craters on

  13. Geological mapping of lunar highland crater Lalande: Topographic configuration, morphology and cratering process

    Science.gov (United States)

    Li, Bo; Ling, Zongcheng; Zhang, Jiang; Chen, Jian; Liu, ChangQing; Bi, Xiangyu

    2018-02-01

    Highland crater Lalande (4.45°S, 8.63°W; D = 23.4 km) is located on the PKT area of the lunar near side, southeast of the Mare Insularum. It is a complex crater in Copernican era and has three distinguishing features: high silicic anomaly, the highest Th abundance and special landforms on its floor. There are some low-relief bulges on the left of Lalande's floor with regular circle or ellipse shapes. They are ∼250-680 m wide and ∼30-91 m high with maximum flank slopes >20°. There are two possible scenarios for the formation of these low-relief bulges which are impact melt products or young silicic volcanic eruptions. We estimated the absolute model ages of the ejecta deposits, several melt ponds and the hummocky floor and determined the ratio of diameter and depth of the crater Lalande. In addition, we found some similar bugle features within other Copernican-aged craters and there were no volcanic source vents on Lalande's floor. Thus, we hypothesized that these low-relief bulges were most consistent with an origin of impact melts during the crater formation instead of small and young volcanic activities occurring on the floor. Based on Kaguya Terrain Camera (TC) ortho-mosaic and Digital Terrain Model (DTM) data produced by TC imagery in stereo, geological units and some linear features on the floor and wall of Lalande have been mapped. Eight geological units are organized by crater floor units: hummocky floor, central peak and low-relief bulges; and crater wall units: terraced walls, channeled and veneered walls, interior walls, mass wasting areas, blocky areas, and melt ponds. These geological units and linear features provided us a chance to understand some details of the cratering process and elevation differences on the floor. We proposed that subsidence due to melt cooling, late-stage wall collapse and rocks uplifted from beneath the surface could be the possible causes of the observed elevation differences on Lalande's floor.

  14. Constructing Stratigraphic Relationships Using Secondary Craters: A Lunar Test Case

    Science.gov (United States)

    Wells, Kassandra; Campbell, D. B.; Campbell, B. A.; Carter, L. M.

    2008-09-01

    Secondary cratering is a possible contaminant of small crater distributions used to date young terrains in the Solar System. As such, much attention has been paid to identifying the effect of the secondary population on the cratering record of various bodies. Our technique utilizes 100m resolution circular polarization ratio (CPR) maps generated from 2.38 GHz Arecibo radar data of the lunar South Pole to distinguish secondary craters from small primaries at large distances from the primary impact. High levels of CPR are indicative of blocky ejecta tails and can be used not only to identify secondaries in this "far field” regime, but can also indicate the associated primary crater by the tail direction. We apply this method to a region on the floor of Newton-A crater ( 60 km diameter), where our refined counts identify 56 secondary craters with diameters above 400m (43.8% of the total population) associated with the primary crater Tycho (85 km diameter)—some 1000 km to the north. In addition to providing information on the relative importance of secondary and primary craters at small diameters, this method of secondary crater identification provides valuable information about the terrains on which they are emplaced. Secondary craters associated with a single primary event form simultaneously, therefore serving as a convenient layer around which stratigraphic relationships can be constructed—particularly if the age of the primary is well constrained. For extensive secondary networks, the semi-global reach of this layer provides a way to compare in a standardized way terrain units separated by thousands of kilometers. As a demonstration of this technique, we employ a combination of crater morphology and CPR tail analysis to determine the ages of features on the floor of Newton-A relative to the layer of Tycho secondaries present there. Funding by NASA's Planetary Astronomy program is acknowledged.

  15. Geologic map of Tooting crater, Amazonis Planitia region of Mars

    Science.gov (United States)

    Mouginis-Mark, Peter J.

    2015-01-01

    Tooting crater has a diameter of 27.2 km, and formed on virtually flat lava flows within Amazonis Planitia ~1,300 km west of the summit of Olympus Mons volcano, where there appear to have been no other major topographic features prior to the impact. The crater formed in an area ~185 x 135 km that is at an elevation between −3,870 m and −3,874 m relative to the Mars Orbiter Laser Altimeter (MOLA) Mars datum. This fortuitous situation (for example, a bland, horizontal target) allows the geometry of the crater and the thickness of the ejecta blanket to be accurately determined by subtracting the appropriate elevation of the surrounding landscape (−3,872 m) from the individual MOLA measurements across the crater. Thus, for the first time, it is possible to determine the radial decrease of ejecta thickness as a function of distance away from the rim crest. On the basis of the four discrete ejecta layers surrounding the crater cavity, Tooting crater is classified as a Multiple-Layered Ejecta (MLE) crater. By virtue of the asymmetric distribution of secondary craters and the greater thickness of ejecta to the northeast, Morris and others (2010) proposed that Tooting crater formed by an oblique impact from the southwest. The maximum range of blocks that produced identifiable secondary craters is ~500 km (~36.0 crater radii) from the northeast rim crest. In contrast, secondary craters are only identifiable ~215 km (15.8 radii) to the southeast and 225 km (16.5 radii) to the west.

  16. Impact spacecraft imagery and comparative morphology of craters

    International Nuclear Information System (INIS)

    Moutsoulas, M.; Piteri, S.

    1979-01-01

    The use of hard-landing 'simple' missions for wide-scale planetary exploration is considered. As an example of their imagery potentialities, Ranger VII data are used for the study of the morphological characteristics of 16 Mare Cognitum craters. The morphological patterns of lunar craters, expressed in terms of the Depth/Diameter ratios appear to be in most cases independent of the crater location or size. (Auth.)

  17. The role of strength defects in shaping impact crater planforms

    Science.gov (United States)

    Watters, W. A.; Geiger, L. M.; Fendrock, M.; Gibson, R.; Hundal, C. B.

    2017-04-01

    High-resolution imagery and digital elevation models (DEMs) were used to measure the planimetric shapes of well-preserved impact craters. These measurements were used to characterize the size-dependent scaling of the departure from circular symmetry, which provides useful insights into the processes of crater growth and modification. For example, we characterized the dependence of the standard deviation of radius (σR) on crater diameter (D) as σR ∼ Dm. For complex craters on the Moon and Mars, m ranges from 0.9 to 1.2 among strong and weak target materials. For the martian simple craters in our data set, m varies from 0.5 to 0.8. The value of m tends toward larger values in weak materials and modified craters, and toward smaller values in relatively unmodified craters as well as craters in high-strength targets, such as young lava plains. We hypothesize that m ≈ 1 for planforms shaped by modification processes (slumping and collapse), whereas m tends toward ∼ 1/2 for planforms shaped by an excavation flow that was influenced by strength anisotropies. Additional morphometric parameters were computed to characterize the following planform properties: the planform aspect ratio or ellipticity, the deviation from a fitted ellipse, and the deviation from a convex shape. We also measured the distribution of crater shapes using Fourier decomposition of the planform, finding a similar distribution for simple and complex craters. By comparing the strength of small and large circular harmonics, we confirmed that lunar and martian complex craters are more polygonal at small sizes. Finally, we have used physical and geometrical principles to motivate scaling arguments and simple Monte Carlo models for generating synthetic planforms, which depend on a characteristic length scale of target strength defects. One of these models can be used to generate populations of synthetic planforms which are very similar to the measured population of well-preserved simple craters on

  18. Floor-Fractured Craters through Machine Learning Methods

    Science.gov (United States)

    Thorey, C.

    2015-12-01

    Floor-fractured craters are impact craters that have undergone post impact deformations. They are characterized by shallow floors with a plate-like or convex appearance, wide floor moats, and radial, concentric, and polygonal floor-fractures. While the origin of these deformations has long been debated, it is now generally accepted that they are the result of the emplacement of shallow magmatic intrusions below their floor. These craters thus constitute an efficient tool to probe the importance of intrusive magmatism from the lunar surface. The most recent catalog of lunar-floor fractured craters references about 200 of them, mainly located around the lunar maria Herein, we will discuss the possibility of using machine learning algorithms to try to detect new floor-fractured craters on the Moon among the 60000 craters referenced in the most recent catalogs. In particular, we will use the gravity field provided by the Gravity Recovery and Interior Laboratory (GRAIL) mission, and the topographic dataset obtained from the Lunar Orbiter Laser Altimeter (LOLA) instrument to design a set of representative features for each crater. We will then discuss the possibility to design a binary supervised classifier, based on these features, to discriminate between the presence or absence of crater-centered intrusion below a specific crater. First predictions from different classifier in terms of their accuracy and uncertainty will be presented.

  19. The large crater on the small Asteroid (2867) Steins

    Science.gov (United States)

    Burchell, M. J.; Leliwa-Kopystynski, J.

    2010-12-01

    The maximum size of impact craters on finite bodies marks the largest impact that can occur short of impact induced disruption of the body. Recently attention has started to focus on large craters on small bodies such as asteroids and rocky and icy satellites. Here the large crater on the recently imaged Asteroid (2867) Steins (with crater diameter to mean asteroid radius ratio of 0.79) is shown to follow a limit set by other similar sized bodies with moderate macroporosity (i.e. fractured asteroids). Thus whilst large, the crater size is not novel, nor does it require Steins to possess an extremely large porosity. In one of the components of the binary Asteroid (90) Antiope there is the recently reported presence of an extremely large depression, possibly a crater, with depression diameter to mean asteroid radius ratio of ˜(1.4-1.62). This is consistent with the maximum size of a crater expected from previous observations of very porous rocky bodies (i.e. rubble-pile asteroids). Finally, a relationship between crater diameter (normalised to body radius) is proposed as a function of body porosity which suggests that the doubling of porosity between fractured asteroids and rubble-pile asteroids, nearly doubles the size ( D/ R value) of the largest crater sustainable on a rocky body.

  20. Determining long-term regional erosion rates using impact craters

    Science.gov (United States)

    Hergarten, Stefan; Kenkmann, Thomas

    2015-04-01

    More than 300,000 impact craters have been found on Mars, while the surface of Moon's highlands is even saturated with craters. In contrast, only 184 impact craters have been confirmed on Earth so far with only 125 of them exposed at the surface. The spatial distribution of these impact craters is highly inhomogeneous. Beside the large variation in the age of the crust, consumption of craters by erosion and burial by sediments are the main actors being responsible for the quite small and inhomogeneous crater record. In this study we present a novel approach to infer long-term average erosion rates at regional scales from the terrestrial crater inventory. The basic idea behind this approach is a dynamic equilibrium between the production of new craters and their consumption by erosion. It is assumed that each crater remains detectable until the total erosion after the impact exceeds a characteristic depth depending on the crater's diameter. Combining this model with the terrestrial crater production rate, i.e., the number of craters per unit area and time as a function of their diameter, allows for a prediction of the expected number of craters in a given region as a function of the erosion rate. Using the real crater inventory, this relationship can be inverted to determine the regional long-term erosion rate and its statistical uncertainty. A limitation by the finite age of the crust can also be taken into account. Applying the method to the Colorado Plateau and the Deccan Traps, both being regions with a distinct geological history, yields erosion rates in excellent agreement with those obtained by other, more laborious methods. However, these rates are formally exposed to large statistical uncertainties due to the small number of impact craters. As higher crater densities are related to lower erosion rates, smaller statistical errors can be expected when large regions in old parts of the crust are considered. Very low long-term erosion rates of less than 4

  1. Secondary Crater-Initiated Debris Flow on the Moon

    Science.gov (United States)

    Martin-Wells, K. S.; Campbell, D. B.; Campbell, B. A.; Carter, L. M.; Fox, Q.

    2016-01-01

    In recent work, radar circular polarization echo properties have been used to identify "secondary" craters without distinctive secondary morphologies. Because of the potential for this method to improve our knowledge of secondary crater population-in particular the effect of secondary populations on crater- derived ages based on small craters-it is important to understand the origin of radar polarization signatures associated with secondary impacts. In this paper, we utilize Lunar Reconnaissance Orbiter Camera photographs to examine the geomorphology of secondary craters with radar circular polarization ratio enhancements. Our investigation reveals evidence of dry debris flow with an impact melt component at such secondary craters. We hypothesize that these debris flows were initiated by the secondary impacts themselves, and that they have entrained blocky material ejected from the secondaries. By transporting this blocky material downrange, we propose that these debris flows (rather than solely ballistic emplacement) are responsible for the tail-like geometries of enhanced radar circular polarization ratio associated with the secondary craters investigated in this work. Evidence of debris flow was observed at both clustered and isolated secondary craters, suggesting that such flow may be a widespread occurrence, with important implications for the mixing of primary and local material in crater rays.

  2. Evidence for self-secondary cratering of Copernican-age continuous ejecta deposits on the Moon

    Science.gov (United States)

    Zanetti, M.; Stadermann, A.; Jolliff, B.; Hiesinger, H.; van der Bogert, C. H.; Plescia, J.

    2017-12-01

    Crater size-frequency distributions on the ejecta blankets of Aristarchus and Tycho Craters are highly variable, resulting in apparent absolute model age differences despite ejecta being emplaced in a geologic instant. Crater populations on impact melt ponds are a factor of 4 less than on the ejecta, and crater density increases with distance from the parent crater rim. Although target material properties may affect crater diameters and in turn crater size-frequency distribution (CSFD) results, they cannot completely reconcile crater density and population differences observed within the ejecta blanket. We infer from the data that self-secondary cratering, the formation of impact craters immediately following the emplacement of the continuous ejecta blanket by ejecta from the parent crater, contributed to the population of small craters (impact melt ponds most accurately reflecting the primary crater flux (N(1) = 3.4 × 10-5). Using the cratering flux recorded on Tycho impact melt deposits calibrated to accepted exposure age (109 ± 1.5 Ma) as ground truth, and using similar crater distribution analyses on impact melt at Aristarchus Crater, we infer the age of Aristarchus Crater to be ∼280 Ma. The broader implications of this work suggest that the measured cratering rate on ejecta blankets throughout the Solar System may be overestimated, and caution should be exercised when using small crater diameters (i.e. < 300 m on the Moon) for absolute model age determination.

  3. A Meteoric Water Budget for the Arctic Ocean

    Science.gov (United States)

    Alkire, Matthew B.; Morison, James; Schweiger, Axel; Zhang, Jinlun; Steele, Michael; Peralta-Ferriz, Cecilia; Dickinson, Suzanne

    2017-12-01

    A budget of meteoric water (MW = river runoff, net precipitation minus evaporation, and glacial meltwater) over four regions of the Arctic Ocean is constructed using a simple box model, regional precipitation-evaporation estimates from reanalysis data sets, and estimates of import and export fluxes derived from the literature with a focus on the 2003-2008 period. The budget indicates an approximate/slightly positive balance between MW imports and exports (i.e., no change in storage); thus, the observed total freshwater increase observed during this time period likely resulted primarily from changes in non-MW freshwater components (i.e., increases in sea ice melt or Pacific water and/or a decrease in ice export). Further, our analysis indicates that the MW increase observed in the Canada Basin resulted from a spatial redistribution of MW over the Arctic Ocean. Mean residence times for MW were estimated for the Western Arctic (5-7 years), Eastern Arctic (3-4 years), and Lincoln Sea (1-2 years). The MW content over the Siberian shelves was estimated (˜14,000 km3) based on a residence time of 3.5 years. The MW content over the entire Arctic Ocean was estimated to be ≥44,000 km3. The MW export through Fram Strait consisted mostly of water from the Eastern Arctic (3,237 ± 1,370 km3 yr-1) whereas the export through the Canadian Archipelago was nearly equally derived from both the Western Arctic (1,182 ± 534 km3 yr-1) and Lincoln Sea (972 ± 391 km3 yr-1).

  4. A model for the dynamics of crater-centered intrusion: Application to lunar floor-fractured craters

    Science.gov (United States)

    Thorey, Clément; Michaut, Chloé

    2014-01-01

    Lunar floor-fractured craters are a class of craters modified by post-impact mechanisms. They are defined by distinctive shallow floors that are convex or plate-like, sometimes with a wide floor moat bordering the wall region. Radial, concentric, and polygonal floor fractures suggest an endogenous process of modification. Two mechanisms have been proposed to account for such deformations: viscous relaxation and spreading of a magma intrusion at depth below the crater. To test the second assumption and bring more constraints on the intrusion process, we develop a model for the dynamics of magma spreading below an elastic overlying layer with a crater-like topography. As predicted in earlier more qualitative studies, the increase in lithostatic pressure at the crater wall zone prevents the intrusion from spreading laterally, leading to the thickening of the intrusion. Additionally, our model shows that the final crater floor appearance after the uplift, which can be convex or flat, with or without a circular moat bordering the wall zone, depends on the elastic thickness of the layer overlying the intrusion and on the crater size. Our model provides a simple formula to derive the elastic thickness of the overlying layer hence a minimum estimate for the intrusion depth. Finally, our model suggests that crust redistribution by cratering must have controlled magma ascent below most of these craters.

  5. Effect of Topography Degradation on Crater Size-Frequency Distributions: Implications for Populations of Small Craters and Age Dating

    Science.gov (United States)

    Xie, Minggang; Zhu, Meng-Hua; Xiao, Zhiyong; Wu, Yunzhao; Xu, Aoao

    2017-10-01

    Whether or not background secondary craters dominate populations of small impact craters on terrestrial bodies is a half-century controversy. It has been suggested that small craters on some planetary bodies are dominated by background secondary craters based partly on the steepened slope of crater size-frequency distribution (CSFD) toward small diameters, such as the less than 1 km diameter crater population on the lunar mare. Here we show that topography degradation enlarges craters and increases CSFD slopes with time. When topography degradation is taken into account, for various-aged crater populations, the observed steep CSFD at small diameters is uniformly consistent with an originally shallower CSFD, whose slope is undifferentiated from the CSFD slope estimated from near-Earth objects and terrestrial bolides. The results show that the effect of topography degradation on CSFD is important in dating planetary surfaces, and the steepening of CSFD slopes is not necessarily caused by secondary cratering, but rather a natural consequence of topography degradation.

  6. Chemistry of cometary meteoroids from video-tape records of meteor spectra

    Science.gov (United States)

    Millman, P. M.

    1982-01-01

    The chemistry of the cometary meteoroids was studied by closed circuit television observing systems. Vidicon cameras produce basic data on standard video tape and enable the recording of the spectra of faint shower meteors, consequently the chemical study is extended to smaller particles and we have a larger data bank than is available from the more conventional method of recording meteor spectra by photography. The two main problems in using video tape meteor spectrum records are: (1) the video tape recording has a much lower resolution than the photographic technique; (2) video tape is relatively new type of data storage in astronomy and the methods of quantitative photometry have not yet been fully developed in the various fields where video tape is used. The use of the most detailed photographic meteor spectra to calibrate the video tape records and to make positive identification of the more prominent chemical elements appearing in the spectra may solve the low resolution problem. Progress in the development of standard photometric techniques for the analysis of video tape records of meteor spectra is reported.

  7. METEOR: An Enterprise Health Informatics Environment to Support Evidence-Based Medicine.

    Science.gov (United States)

    Puppala, Mamta; He, Tiancheng; Chen, Shenyi; Ogunti, Richard; Yu, Xiaohui; Li, Fuhai; Jackson, Robert; Wong, Stephen T C

    2015-12-01

    The aim of this paper is to propose the design and implementation of next-generation enterprise analytics platform developed at the Houston Methodist Hospital (HMH) system to meet the market and regulatory needs of the healthcare industry. For this goal, we developed an integrated clinical informatics environment, i.e., Methodist environment for translational enhancement and outcomes research (METEOR). The framework of METEOR consists of two components: the enterprise data warehouse (EDW) and a software intelligence and analytics (SIA) layer for enabling a wide range of clinical decision support systems that can be used directly by outcomes researchers and clinical investigators to facilitate data access for the purposes of hypothesis testing, cohort identification, data mining, risk prediction, and clinical research training. Data and usability analysis were performed on METEOR components as a preliminary evaluation, which successfully demonstrated that METEOR addresses significant niches in the clinical informatics area, and provides a powerful means for data integration and efficient access in supporting clinical and translational research. METEOR EDW and informatics applications improved outcomes, enabled coordinated care, and support health analytics and clinical research at HMH. The twin pressures of cost containment in the healthcare market and new federal regulations and policies have led to the prioritization of the meaningful use of electronic health records in the United States. EDW and SIA layers on top of EDW are becoming an essential strategic tool to healthcare institutions and integrated delivery networks in order to support evidence-based medicine at the enterprise level.

  8. Mass distribution of meteoroids obtained by a meteor forward-scattered (MFS) radar method

    International Nuclear Information System (INIS)

    Cevolani, G.; Gabucci, M.

    1996-01-01

    The cumulative distributions of the number vs. duration of echoes belonging to main meteor showers (Lyrids, η-Aquarids, δ-Aquarids, Perseids, Orionids, Leonids, Geminids) and sporadic background were investigated using a forward-scattered (FS) continuous-wave (CW) meteor radar link operational during 1992-95 over the long baseline Bologna-Lecce in Italy. The trend of the mass distribution of particles in the quoted meteoroid streams was derived, and the values of the mass index s were compared for each meteor population with the steady-state condition (s<11/6): It was found that the mass index s generally increases towards long duration echoes, but many of the observed meteor streams appear to have unstable populations. The values of the mass index of the sporadic complex are generally higher (2.07<=s<=2.57) than the corresponding ones of meteor showers in the range of echo durations 0.1<=T<=10 s. This is a possible consequence of longer lasting FS signals, indicating a shift of the mass distribution function vs, higher echo durations. Moreover,non-gravitational forces in connection with solar radiation pressure, Poynting-Robertson effect, solar-wind particle streaming, mutual collisions, etc., appear to be responsible for the observed widespread radiants and for unstable populations in the meteoroid stream

  9. Cratering record in the inner solar system: Implications for earth

    International Nuclear Information System (INIS)

    Barlow, N.G.

    1988-01-01

    Internal and external processes have reworked the Earth's surface throughout its history. In particular, the effect of meteorite impacts on the early history of the earth is lost due to fluvial, aeolian, volcanic and plate tectonic action. The cratering record on other inner solar system bodies often provides the only clue to the relative cratering rates and intensities that the earth has experienced throughout its history. Of the five major bodies within the inner solar system, Mercury, Mars, and the Moon retain scars of an early episode of high impact rates. The heavily cratered regions on Mercury, Mars, and the Moon show crater size-frequency distribution curves similar in shape and crater density, whereas the lightly cratered plains on the Moon and Mars show distribution curves which, although similar to each other, are statistically different in shape and density from the more heavily cratered units. The similarities among crater size-frequency distribution curves for the Moon, Mercury, and Mars suggest that the entire inner solar system was subjected to the two populations of impacting objects but Earth and Venus have lost their record of heavy bombardment impactors. Thus, based on the cratering record on the Moon, Mercury, and Mars, it can be inferred that the Earth experienced a period of high crater rates and basin formation prior to about 3.8 BY ago. Recent studies have linked mass extinctions to large terrestrial impacts, so life forms were unable to establish themselves until impact rates decreased substantially and terrestrial conditions became more benign. The possible periodicity of mass extinctions has led to the theory of fluctuating impact rates due to comet showers in the post heavy bombardment period. The active erosional environment on the Earth complicates attempts to verify these showers by erasing geological evidence of older impact craters

  10. Detection of lunar floor-fractured craters using machine learning methods

    Science.gov (United States)

    Thorey, C.

    2015-10-01

    About 200 Floor Fractured Craters (FFCs) have been identified by Schultz (1976) on the Moon, mainly around the lunar maria. These craters are a class of impact craters that are distinguished by having radi-ally and concentric floor-fractured networks and ab-normally shallow floors. In some cases, the uplift of the crater floor can be as large as 50% of the initial crater depth. These impact craters are interpreted to have undergone endogenous deformations after their formation.

  11. The extra-atmospheric masses of small meteoric fireballs from the Prairie and the Canadian camera networks.

    Science.gov (United States)

    Popelenskaya, N.

    2007-08-01

    Existing methods of definition of extra-atmospheric masses of small meteoric bodies according to supervision of their movement in an atmosphere contain the certain arbitrariness. Vigorous attempts to overcome a divergence of results of calculations on the basis of various approaches often lead to physically incorrect conclusions. The output consists in patient accumulation of estimations and calculations for gradual elimination uncertainties. The equations of meteoric physics include two dimensionless parameters - factor ablation ? and factor of braking ?. In work are cited the data processing supervision of small meteors Prairie and Canadian networks, by a finding of values of parameters ? and ? with use of a method of the least squares. Also values of heights blackout a meteor which turn out from conditions of full destruction or final braking with use of the received values of ? and ? are considered. In prevailing number of supervision for considered meteors braking is insignificant. Results of calculations of height of blackout meteors confirm suitability of the approximations used in work for the description of movement of small meteors. In work results of calculation of extra-atmospheric masses with use of factor of braking for meteoric bodies of the spherical form with density of an ice and a stone are presented. On the basis of the received results discrepancy of photometric masses to values of masses of the input, received on observable braking proves to be true. In most cases received magnitude of masses essentially less photometric masses. Processing of supervision of small meteors Prairie and Canadian camera networks has shown, that the so-called photometric mass mismatches values of mass of the input, defined on observable braking. Acceptance of photometric value as the mass defining braking of a body, leads to obviously underestimated values of density of substance meteoric body. The further researches on specification of interpretation of supervision

  12. 36 CFR 7.2 - Crater Lake National Park.

    Science.gov (United States)

    2010-07-01

    ... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Crater Lake National Park. 7.2 Section 7.2 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR SPECIAL REGULATIONS, AREAS OF THE NATIONAL PARK SYSTEM § 7.2 Crater Lake National Park. (a) Fishing...

  13. Determination of lunar surface ages from crater frequency–size ...

    Indian Academy of Sciences (India)

    Crater size–frequency distribution is one of the powerful techniques to estimate the ages of planetary surfaces, especially from remote sensing studies. This has been applied to images of the Moon obtained from Clementine mission in 1994. Simple techniques of measurement of the diameter of the craters (in pixels) are ...

  14. Radio observation of meteors at the Slovak Central Observatory in Hurbanovo

    Science.gov (United States)

    Dolinský, P.

    2015-01-01

    From 4 November 2014, we started registration of meteors using radio waves at the Slovak Central Observatory in Hurbanovo. Our 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 registration using HROFFT v1.0.0f. Received data were statistically processed and compared with shower activity. Not all of the echoes have meteoric origin, but are caused also by ionospheric Es layer. Registrations are also disturbed by lightning.

  15. The Innisfree meteorite: Dynamical history of the orbit - Possible family of meteor bodies

    Science.gov (United States)

    Galibina, I. V.; Terent'eva, A. K.

    1987-09-01

    Evolution of the Innisfree meteorite orbit caused by secular perturbations is studied over the time interval of 500000 yrs (from the current epoch backwards). Calculations are made by the Gauss-Halphen-Gorjatschew method taking into account perturbations from the four outer planets - Jupiter, Saturn, Uranus and Neptune. In the above mentioned time interval the meteorite orbit has undergone no essential transformations. The Innisfree orbit intersected in 91 cases the Earth orbit and in 94 - the Mars orbit. A system of small and large meteor bodies (producing ordinary meteors and fireballs) which may be genetically related to the Innisfree meteorite has been found, i.e. there probably exists an Innisfree family of meteor bodies.

  16. The MeTeOR trial (Meniscal Tear in Osteoarthritis Research): rationale and design features.

    Science.gov (United States)

    Katz, Jeffrey N; Chaisson, Christine E; Cole, Brian; Guermazi, Ali; Hunter, David J; Jones, Morgan; Levy, Bruce A; Mandl, Lisa A; Martin, Scott; Marx, Robert G; Safran-Norton, Clare; Roemer, Frank W; Skoniecki, Debra; Solomon, Daniel H; Spindler, Kurt P; Wright, John; Wright, Rick W; Losina, Elena

    2012-11-01

    This paper presents the rationale and design features of the MeTeOR Trial (Meniscal Tear in Osteoarthritis Research; Clinical Trials.gov NCT00597012). MeTeOR is an NIH-funded seven-center prospective randomized controlled trial (RCT) designed to establish the efficacy of arthroscopic partial meniscectomy combined with a standardized physical therapy program as compared with a standardized physical therapy program alone in patients with a symptomatic meniscal tear in the setting of mild to moderate knee osteoarthritic change (OA). The design and execution of a trial that compares surgery with a nonoperative treatment strategy presents distinctive challenges. The goal of this paper is to provide the clinical rationale for MeTeOR and to highlight salient design features, with particular attention to those that present clinical and methodologic challenges. Copyright © 2012 Elsevier Inc. All rights reserved.

  17. Evolution of Occator Crater on (1) Ceres

    Energy Technology Data Exchange (ETDEWEB)

    Nathues, A.; Platz, T.; Thangjam, G.; Hoffmann, M.; Corre, L. Le; Reddy, V.; Kallisch, J. [Max Planck Institute for Solar System Research, Justus-von-Liebig-Weg 3, 37077 Goettingen (Germany); Mengel, K. [IELF, TU Clausthal, Adolph-Roemer-Straße 2A, 38678 Clausthal-Zellerfeld (Germany); Cloutis, E. A. [University of Winnipeg, Winnipeg, MB R3B 2E (Canada); Crown, D. A., E-mail: nathues@mps.mpg.de, E-mail: platz@mps.mpg.de, E-mail: thangjam@mps.mpg.de, E-mail: hoffmann@mps.mpg.de, E-mail: kallisch@mps.mpg.de, E-mail: gkmengel@t-online.de, E-mail: e.cloutis@uwinnipeg.ca, E-mail: lecorre@psi.edu, E-mail: reddy@psi.edu, E-mail: crown@psi.edu [Planetary Science Institute, 1700 East Fort Lowell Rd, Suite 106, Tucson, AZ 85719-2395 (United States)

    2017-03-01

    The dwarf planet Ceres (diameter 939 km) is the largest object in the main asteroid belt. Recent investigations suggest that Ceres is a thermally evolved, volatile-rich body with potential geological activity, a body which was never completely molten but possibly differentiated into a rocky core, an ice-rich mantle, and which may contain remnant internal liquid water. Thermal alteration and exogenic material infall contribute to producing a (dark) carbonaceous chondritic-like surface containing ammoniated phyllosilicates. Here we report imaging and spectroscopic analyses of Occator crater derived from the Framing Camera and the Visible and Infrared Spectrometer onboard Dawn. We found that the central bright spot (Cerealia Facula) of Occator is ∼30 Myr younger than the crater itself. The central spot is located in a central pit which contains a dome that is spectrally homogenous, exhibiting absorption features that are consistent with carbonates. Multiple radial fractures across the dome indicate an extrusive formation process. Our results lead us to conclude that the floor region was subject to past endogenic activity. Dome and bright material in its vicinity formed likely due to a long-lasting, periodic, or episodic ascent of bright material from a subsurface reservoir rich in carbonates. Originally triggered by an impact event, gases, possibly dissolved from a subsurface water/brine layer, enabled material rich in carbonates to ascend through fractures and be deposited onto the surface.

  18. About Catalogue of Orbit and Atmospheric Trajectory of 4500 Radio Meteors Brighter +5m

    Science.gov (United States)

    Narziev, M.; Tshebotaryov, P.

    2017-09-01

    Published by this time the majority of catalogues of a radiant, speeds and elements of orbits of meteors, basically, are based on a interpretation of the given radio observations by diffraction-time a method. However the given method is applicable for processing of 15-25 % of observed meteors that leads to loss of the most part of an observed material. Besides, the error of measurement of an antiaircraft corner of a radiant σZr with increase in a corner to 60°÷70 ° will be increased in 2-3 times, and at the further increase in a corner the error grows even faster, so measurements lose meaning. In 1968-1970 in action period of the Soviet equatorial meteor expedition to Somalia, simultaneously and radio observations of meteors in HisAO from four points have been resulted. For interpretation of the radar data the bearing-time method radio method developed and applied for the first time in Tajikistan is used. This approximately twice increases number of the measured radiant and speeds. What's more, the error of measurement of an antiaircraft corner does not depend on antiaircraft distance of a radiant. The velocity of meteor is determined by the bearing-time method, and by the diffraction picture. In the catalogue along with a radiant, speeds and elements of orbits, for the first time the height, value of linear electronic density, radio magnitude and masses of each of 4500 radio meteors registered since December 1968 till May, 1969 are resulted.

  19. Mass Movement on Vesta at Steep Scarps and Crater Rims

    Science.gov (United States)

    Krohn, K.; Jaumann, R.; Otto, K.; Hoogenboom, T.; Wagner, R.; Buczkowski, D. L.; Garry, B.; Williams, D. A.; Yingst, R. A.; Scully, J.; hide

    2014-01-01

    The Quadrangles Av-11 and Av-12 on Vesta are located at the northern rim of the giant Rheasilvia south polar impact basin. The primary geologic units in Av-11 and Av-12 include material from the Rheasilvia impact basin formation, smooth material and different types of impact crater structures (such as bimodal craters, dark and bright crater ray material and dark ejecta material). Av-11 and Av-12 exhibit almost the full range of mass wasting features observed on Vesta, such as slump blocks, spur-and-gully morphologies and landslides within craters. Processes of collapse, slope instability and seismically triggered events force material to slump down crater walls or scarps and produce landslides or rotational slump blocks. The spur-and-gully morphology that is known to form on Mars is also observed on Vesta; however, on Vesta this morphology formed under dry conditions.

  20. Acoustic fluidization and the scale dependence of impact crater morphology

    Science.gov (United States)

    Melosh, H. J.; Gaffney, E. S.

    1983-01-01

    A phenomenological Bingham plastic model has previously been shown to provide an adequate description of the collapse of impact craters. This paper demonstrates that the Bingham parameters may be derived from a model in which acoustic energy generated during excavation fluidizes the rock debris surrounding the crater. Experimental support for the theoretical flow law is presented. Although the Bingham yield stress cannot be computed without detailed knowledge of the initial acoustic field, the Bingham viscosity is derived from a simple argument which shows that it increases as the 3/2 power of crater diameter, consistent with observation. Crater collapse may occur in material with internal dissipation Q as low as 100, comparable to laboratory observations of dissipation in granular materials. Crater collapse thus does not require that the acoustic field be regenerated during flow.

  1. Crater ejecta scaling laws - Fundamental forms based on dimensional analysis

    Science.gov (United States)

    Housen, K. R.; Schmidt, R. M.; Holsapple, K. A.

    1983-01-01

    Self-consistent scaling laws are developed for meteoroid impact crater ejecta. Attention is given to the ejection velocity of material as a function of the impact point, the volume of ejecta with a threshold velocity, and the thickness of ejecta deposit in terms of the distance from the impact. Use is made of recently developed equations for energy and momentum coupling in cratering events. Consideration is given to scaling of laboratory trials up to real-world events and formulations are developed for calculating the ejection velocities and ejecta blanket profiles in the gravity and strength regimes of crater formation. It is concluded that, in the gravity regime, the thickness of an ejecta blanket is the same in all directions if the thickness and range are expressed in terms of the crater radius. In the strength regime, however, the ejecta velocities are independent of crater size, thereby allowing for asymmetric ejecta blankets. Controlled experiments are recommended for the gravity/strength transition.

  2. An Initial Meteoroid Stream Survey in the Southern Hemisphere Using the Southern Argentina Agile Meteor Radar (SAAMER)

    Science.gov (United States)

    Janches, D.; Hormaechea, J. L.; Brunini, C.; Hocking, W.; Fritts, D. C.

    2013-01-01

    We present in this manuscript a 4 year survey of meteor shower radiants utilizing the Southern Argentina Agile Meteor Radar (SAAMER). SAAMER, which operates at the southern most region of South America, is a new generation SKiYMET system designed with significant differences from typical meteor radars including high transmitted power and an 8-antenna transmitting array enabling large detected rates at low zenith angles. We applied the statistical methodology developed by Jones and Jones (Jones, J., Jones, W. [2006]. Month. Not. R. Astron. Soc. 367, 1050-1056) to the data collected each day and compiled the results into 1 composite representative year at 1 resolution in Solar Longitude. We then search for enhancements in the activity which last for at least 3 days and evolve temporally as is expected from a meteor shower. Using this methodology, we have identified in our data 32 shower radiants, two of which were not part of the IAU commission 22 meteor shower working list. Recently, SAAMER's capabilities were enhanced by adding two remote stations to receive meteor forward scatter signals from meteor trails and thus enable the determination of meteoroid orbital parameters. SAAMER started recording orbits in January 2012 and future surveys will focus on the search for unknown meteor streams, in particular in the southern ecliptic sky.

  3. Identification of Optical Component of North Toroidal Source of Sporadic Meteors and its Origin

    Science.gov (United States)

    Hashimoto, T.; Watanabe, J.; Sato, M.; Ishiguro, M.

    2011-01-01

    We succeeded to identify the North Toroidal source by optical observations performed by the SonotaCo Network, which is a TV observation network coordinated by Japanese amateurs. This source has been known only for radar observations until now. The orbits of the optical meteors in the North Toroidal source are relatively large eccentricity and semi-major axis, compared with those of the radar meteors. In this paper, we report the characteristics of this North Toroidal source detected by optical observations, and discuss the possible origin and evolution of this source.

  4. Simple Impact Crater Shapes From Shadows - The Sequel

    Science.gov (United States)

    Chappelow, J. E.

    2008-12-01

    At the last LPSC meeting I presented the outline of a method for determining simple impact crater shapes from shadows. In theory the shadow cast within a simple crater provides enough information to derive its cross-sectional shape from shadow measurements, at least to the maximum depth to which the shadow extends. Under certain simple assumptions, this can be done analytically. If the crater is conic-section - shaped, then it can be shown that the down-sun bound of any shadow cast within it is elliptical, with one axis along the direction of illumination and the other (perpendicular to it) of semi-length D/2 (where D is diameter). The properties of this shadow-ellipse can be related to the parameters of the crater shape conic-section, thus measurements of the shadow-ellipse yield not only crater depth and diameter but also the approximate crater shape, in terms of conic sections. The method also does not depend upon the shadow crossing near the crater center, which avoids a pitfall of older shadow measurement methods. The technique is also amenable to computer implementation, which has already been largely completed. Once computerized, crater measurements can be made rapidly and repeatably. The program reads in an image, its resolution, and the solar elevation and azimuth. The user then defines the crater rim by 'clicking' on three points, and the shadow ellipse by clicking on two more. The program calculates and outputs the diameter, the depth, and parameters describing the crater's approximating conic-section. It is highly applicable to situations where only single-image photography is available, for example MESSENGER flybys of Mercury. At the meeting I will present the finished math for this method and give some examples of its use.

  5. LU60645GT and MA132843GT Catalogues of Lunar and Martian Impact Craters Developed Using a Crater Shape-based Interpolation Crater Detection Algorithm for Topography Data

    Science.gov (United States)

    Salamuniccar, Goran; Loncaric, Sven; Mazarico, Erwan Matias

    2012-01-01

    For Mars, 57,633 craters from the manually assembled catalogues and 72,668 additional craters identified using several crater detection algorithms (CDAs) have been merged into the MA130301GT catalogue. By contrast, for the Moon the most complete previous catalogue contains only 14,923 craters. Two recent missions provided higher-quality digital elevation maps (DEMs): SELENE (in 1/16° resolution) and Lunar Reconnaissance Orbiter (we used up to 1/512°). This was the main motivation for work on the new Crater Shape-based interpolation module, which improves previous CDA as follows: (1) it decreases the number of false-detections for the required number of true detections; (2) it improves detection capabilities for very small craters; and (3) it provides more accurate automated measurements of craters' properties. The results are: (1) LU60645GT, which is currently the most complete (up to D>=8 km) catalogue of Lunar craters; and (2) MA132843GT catalogue of Martian craters complete up to D>=2 km, which is the extension of the previous MA130301GT catalogue. As previously achieved for Mars, LU60645GT provides all properties that were provided by the previous Lunar catalogues, plus: (1) correlation between morphological descriptors from used catalogues; (2) correlation between manually assigned attributes and automated measurements; (3) average errors and their standard deviations for manually and automatically assigned attributes such as position coordinates, diameter, depth/diameter ratio, etc; and (4) a review of positional accuracy of used datasets. Additionally, surface dating could potentially be improved with the exhaustiveness of this new catalogue. The accompanying results are: (1) the possibility of comparing a large number of Lunar and Martian craters, of e.g. depth/diameter ratio and 2D profiles; (2) utilisation of a method for re-projection of datasets and catalogues, which is very useful for craters that are very close to poles; and (3) the extension of the

  6. Fourier analysis of planimetric lunar crater shape - Possible guide to impact history and lunar geology

    Science.gov (United States)

    Eppler, D. T.; Nummedal, D.; Ehrlich, R.

    1977-01-01

    If the lithology of lunar crust influences impact crater morphology, a method of analysis that is sensitive to small-scale changes in crater shape is required. In the present paper, it is shown that Fourier analysis in closed form can provide detailed information regarding planimetric crater shape. Preliminary analysis of the rim crest outline of 247 nearside lunar craters (larger than 18 km in diam) led to the following information: Imbrian and pre-Imbrian craters are more elongate than younger craters, possibly as a result of widespread crustal deformation early in the moon's history. Crater size does not affect the planimetric shape of craters. Highland craters are less circular than mare craters, probably due to the greater structural and lithologic complexity of the highland crust. Craters comprising each shape family of the eleventh harmonic typically are located in the same general geographic region of the moon.

  7. 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)

  8. 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).

  9. On shock waves and the role of hyperthermal chemistry in the early diffusion of overdense meteor trains

    Science.gov (United States)

    Silber, Elizabeth A.; Hocking, Wayne K.; Niculescu, Mihai L.; Gritsevich, Maria; Silber, Reynold E.

    2017-08-01

    Studies of meteor trails have until now been limited to relatively simple models, with the trail often being treated as a conducting cylinder, and the head (if considered at all) treated as a ball of ionized gas. In this article, we bring the experience gleaned from other fields to the domain of meteor studies, and adapt this prior knowledge to give a much clearer view of the microscale physics and chemistry involved in meteor-trail formation, with particular emphasis on the first 100 or so milliseconds of the trail formation. We discuss and examine the combined physicochemical effects of meteor-generated and ablationally amplified cylindrical shock waves that appear in the ambient atmosphere immediately surrounding the meteor train, as well as the associated hyperthermal chemistry on the boundaries of the high temperature post-adiabatically expanding meteor train. We demonstrate that the cylindrical shock waves produced by overdense meteors are sufficiently strong to dissociate molecules in the ambient atmosphere when it is heated to temperatures in the vicinity of 6000 K, which substantially alters the considerations of the chemical processes in and around the meteor train. We demonstrate that some ambient O2, along with O2 that comes from the shock dissociation of O3, survives the passage of the cylindrical shock wave, and these constituents react thermally with meteor metal ions, thereby subsequently removing electrons from the overdense meteor train boundary through fast, temperature-independent, dissociative recombination governed by the second Damköhler number. Possible implications for trail diffusion and lifetimes are discussed.

  10. Riddles in the Dark: Imaging Inside Mercury's Permanently Shadowed Craters

    Science.gov (United States)

    Ernst, C. M.; Chabot, N. L.; Denevi, B. W.; Nair, H.; Deutsch, A. N.; Murchie, S. L.; Robinson, M. S.; Blewett, D. T.; Head, J. W.; Harmon, J. K.; Neumann, G. A.; Solomon, S. C.

    2013-12-01

    Numerous lines of evidence independently point to the presence of water ice in Mercury's polar regions: Earth-based radar shows radar-bright regions; Mariner 10 and MESSENGER Mercury Dual Imaging System (MDIS) images reveal that these regions are permanently (south polar region) or persistently (north polar region) shadowed; neutron spectrometry indicates hydrogen-rich material; thermal models support the presence of water ice; and Mercury Laser Altimeter (MLA) reflectance measurements at 1064 nm show high and low reflectance deposits consistent in location to where models predict surface and buried water ice, respectively. Throughout 2013, MESSENGER executed a campaign dedicated to imaging the permanently shadowed crater floors of Mercury's north polar region using sunlight scattered from nearby terrain. The campaign makes use of the broadband clear filter (central wavelength 700 nm, bandwidth 600 nm) of the MDIS wide-angle camera (WAC) to target and image radar-bright areas within all host craters > 10 km in diameter under multiple lighting conditions. To date, MESSENGER has imaged the interiors of nearly 20 craters that host radar-bright deposits, including the largest such deposits near the north pole that are likely to host surface water ice. The images reveal a variety of surface morphologies, ranging from the smooth crater floor of the fresh Kandinsky crater, to the moderately cratered floor of Tolkien crater, and to the battered floor of Prokofiev crater, in which the permanently shadowed region does not differ morphologically from the rest of the crater floor. Thus, no distinct morphology is identified in association with polar deposits, and craters hosting such material span the typical range of degradation states relative to their illuminated counterparts. MDIS images also reveal albedo differences in craters with floors not fully in permanent shadow. Prokofiev provides a special environment for viewing a radar- and MLA-bright region suspected to host

  11. Secondary Craters and the Size-Velocity Distribution of Ejected Fragments around Lunar Craters Measured Using LROC Images

    Science.gov (United States)

    Singer, K. N.; Jolliff, B. L.; McKinnon, W. B.

    2013-12-01

    Title: Secondary Craters and the Size-Velocity Distribution of Ejected Fragments around Lunar Craters Measured Using LROC Images Authors: Kelsi N. Singer1, Bradley L. Jolliff1, and William B. McKinnon1 Affiliations: 1. Earth and Planetary Sciences, Washington University in St Louis, St. Louis, MO, United States. We report results from analyzing the size-velocity distribution (SVD) of secondary crater forming fragments from the 93 km diameter Copernicus impact. We measured the diameters of secondary craters and their distances from Copernicus using LROC Wide Angle Camera (WAC) and Narrow Angle Camera (NAC) image data. We then estimated the velocity and size of the ejecta fragment that formed each secondary crater from the range equation for a ballistic trajectory on a sphere and Schmidt-Holsapple scaling relations. Size scaling was carried out in the gravity regime for both non-porous and porous target material properties. We focus on the largest ejecta fragments (dfmax) at a given ejection velocity (υej) and fit the upper envelope of the SVD using quantile regression to an equation of the form dfmax = A*υej ^- β. The velocity exponent, β, describes how quickly fragment sizes fall off with increasing ejection velocity during crater excavation. For Copernicus, we measured 5800 secondary craters, at distances of up to 700 km (15 crater radii), corresponding to an ejecta fragment velocity of approximately 950 m/s. This mapping only includes secondary craters that are part of a radial chain or cluster. The two largest craters in chains near Copernicus that are likely to be secondaries are 6.4 and 5.2 km in diameter. We obtained a velocity exponent, β, of 2.2 × 0.1 for a non-porous surface. This result is similar to Vickery's [1987, GRL 14] determination of β = 1.9 × 0.2 for Copernicus using Lunar Orbiter IV data. The availability of WAC 100 m/pix global mosaics with illumination geometry optimized for morphology allows us to update and extend the work of Vickery

  12. Noachian and more recent phyllosilicates in impact craters on Mars.

    Science.gov (United States)

    Fairén, Alberto G; Chevrier, Vincent; Abramov, Oleg; Marzo, Giuseppe A; Gavin, Patricia; Davila, Alfonso F; Tornabene, Livio L; Bishop, Janice L; Roush, Ted L; Gross, Christoph; Kneissl, Thomas; Uceda, Esther R; Dohm, James M; Schulze-Makuch, Dirk; Rodríguez, J Alexis P; Amils, Ricardo; McKay, Christopher P

    2010-07-06

    Hundreds of impact craters on Mars contain diverse phyllosilicates, interpreted as excavation products of preexisting subsurface deposits following impact and crater formation. This has been used to argue that the conditions conducive to phyllosilicate synthesis, which require the presence of abundant and long-lasting liquid water, were only met early in the history of the planet, during the Noachian period (> 3.6 Gy ago), and that aqueous environments were widespread then. Here we test this hypothesis by examining the excavation process of hydrated minerals by impact events on Mars and analyzing the stability of phyllosilicates against the impact-induced thermal shock. To do so, we first compare the infrared spectra of thermally altered phyllosilicates with those of hydrated minerals known to occur in craters on Mars and then analyze the postshock temperatures reached during impact crater excavation. Our results show that phyllosilicates can resist the postshock temperatures almost everywhere in the crater, except under particular conditions in a central area in and near the point of impact. We conclude that most phyllosilicates detected inside impact craters on Mars are consistent with excavated preexisting sediments, supporting the hypothesis of a primeval and long-lasting global aqueous environment. When our analyses are applied to specific impact craters on Mars, we are able to identify both pre- and postimpact phyllosilicates, therefore extending the time of local phyllosilicate synthesis to post-Noachian times.

  13. Crater Topography on Titan: Implications for Landscape Evolution

    Science.gov (United States)

    Neish, Catherine D.; Kirk, R.L.; Lorenz, R. D.; Bray, V. J.; Schenk, P.; Stiles, B. W.; Turtle, E.; Mitchell, K.; Hayes, A.

    2013-01-01

    We present a comprehensive review of available crater topography measurements for Saturn's moon Titan. In general, the depths of Titan's craters are within the range of depths observed for similarly sized fresh craters on Ganymede, but several hundreds of meters shallower than Ganymede's average depth vs. diameter trend. Depth-to-diameter ratios are between 0.0012 +/- 0.0003 (for the largest crater studied, Menrva, D approximately 425 km) and 0.017 +/- 0.004 (for the smallest crater studied, Ksa, D approximately 39 km). When we evaluate the Anderson-Darling goodness-of-fit parameter, we find that there is less than a 10% probability that Titan's craters have a current depth distribution that is consistent with the depth distribution of fresh craters on Ganymede. There is, however, a much higher probability that the relative depths are uniformly distributed between 0 (fresh) and 1 (completely infilled). This distribution is consistent with an infilling process that is relatively constant with time, such as aeolian deposition. Assuming that Ganymede represents a close 'airless' analogue to Titan, the difference in depths represents the first quantitative measure of the amount of modification that has shaped Titan's surface, the only body in the outer Solar System with extensive surface-atmosphere exchange.

  14. Crater topography on Titan: implications for landscape evolution

    Science.gov (United States)

    Neish, Catherine D.; Kirk, R.L.; Lorenz, R.D.; Bray, V.J.; Schenk, P.; Stiles, B.W.; Turtle, E.; Mitchell, Ken; Hayes, A.

    2013-01-01

    We present a comprehensive review of available crater topography measurements for Saturn’s moon Titan. In general, the depths of Titan’s craters are within the range of depths observed for similarly sized fresh craters on Ganymede, but several hundreds of meters shallower than Ganymede’s average depth vs. diameter trend. Depth-to-diameter ratios are between 0.0012 ± 0.0003 (for the largest crater studied, Menrva, D ~ 425 km) and 0.017 ± 0.004 (for the smallest crater studied, Ksa, D ~ 39 km). When we evaluate the Anderson–Darling goodness-of-fit parameter, we find that there is less than a 10% probability that Titan’s craters have a current depth distribution that is consistent with the depth distribution of fresh craters on Ganymede. There is, however, a much higher probability that the relative depths are uniformly distributed between 0 (fresh) and 1 (completely infilled). This distribution is consistent with an infilling process that is relatively constant with time, such as aeolian deposition. Assuming that Ganymede represents a close ‘airless’ analogue to Titan, the difference in depths represents the first quantitative measure of the amount of modification that has shaped Titan’s surface, the only body in the outer Solar System with extensive surface–atmosphere exchange.

  15. The Morphology of Craters on Mercury: Results from MESSENGER Flybys

    Science.gov (United States)

    Barnouin, Oliver S.; Zuber, Maria T.; Smith, David E.; Neumann, Gregory A.; Herrick, Robert R.; Chappelow, John E.; Murchie, Scott L.; Prockter, Louise M.

    2012-01-01

    Topographic data measured from the Mercury Laser Altimeter (MLA) and the Mercury Dual Imaging System (MDIS) aboard the MESSENGER spacecraft were used for investigations of the relationship between depth and diameter for impact craters on Mercury. Results using data from the MESSENGER flybys of the innermost planet indicate that most of the craters measured with MLA are shallower than those previously measured by using Mariner 10 images. MDIS images of these same MLA-measured craters show that they have been modified. The use of shadow measurement techniques, which were found to be accurate relative to the MLA results, indicate that both small bowl-shaped and large complex craters that are fresh possess depth-to-diameter ratios that are in good agreement with those measured from Mariner 10 images. The preliminary data also show that the depths of modified craters are shallower relative to fresh ones, and might provide quantitative estimates of crater in-filling by subsequent volcanic or impact processes. The diameter that defines the transition from simple to complex craters on Mercury based on MESSENGER data is consistent with that reported from Mariner 10 data.

  16. Slope activity in Gale crater, Mars

    Science.gov (United States)

    Dundas, Colin M.; McEwen, Alfred S.

    2015-01-01

    High-resolution repeat imaging of Aeolis Mons, the central mound in Gale crater, reveals active slope processes within tens of kilometers of the Curiosity rover. At one location near the base of northeastern Aeolis Mons, dozens of transient narrow lineae were observed, resembling features (Recurring Slope Lineae) that are potentially due to liquid water. However, the lineae faded and have not recurred in subsequent Mars years. Other small-scale slope activity is common, but has different spatial and temporal characteristics. We have not identified confirmed RSL, which Rummel et al. (Rummel, J.D. et al. [2014]. Astrobiology 14, 887–968) recommended be treated as potential special regions for planetary protection. Repeat images acquired as Curiosity approaches the base of Aeolis Mons could detect changes due to active slope processes, which could enable the rover to examine recently exposed material.

  17. Martian Fluvial Conglomerates at Gale Crater

    Science.gov (United States)

    Williams, R. M. E.; Grotzinger, J. P.; Dietrich, W. E.; Gupta, S.; Sumner, D. Y.; Wiens, R. C.; Mangold, N.; Malin, M. C.; Edgett, K. S.; Maurice, S.; Forni, O.; Gasnault, O.; Ollila, A.; Newsom, H. E.; Dromart, G.; Palucis, M. C.; Yingst, R. A.; Anderson, R. B.; Herkenhoff, K. E.; Le Mouélic, S.; Goetz, W.; Madsen, M. B.; Koefoed, A.; Jensen, J. K.; Bridges, J. C.; Schwenzer, S. P.; Lewis, K. W.; Stack, K. M.; Rubin, D.; Kah, L. C.; Bell, J. F.; Farmer, J. D.; Sullivan, R.; Van Beek, T.; Blaney, D. L.; Pariser, O.; Deen, R. G.; Kemppinen, Osku; Bridges, Nathan; Johnson, Jeffrey R.; Minitti, Michelle; Cremers, David; Edgar, Lauren; Godber, Austin; Wadhwa, Meenakshi; Wellington, Danika; McEwan, Ian; Newman, Claire; Richardson, Mark; Charpentier, Antoine; Peret, Laurent; King, Penelope; Blank, Jennifer; Weigle, Gerald; Schmidt, Mariek; Li, Shuai; Milliken, Ralph; Robertson, Kevin; Sun, Vivian; Baker, Michael; Edwards, Christopher; Ehlmann, Bethany; Farley, Kenneth; Griffes, Jennifer; Miller, Hayden; Newcombe, Megan; Pilorget, Cedric; Rice, Melissa; Siebach, Kirsten; Stolper, Edward; Brunet, Claude; Hipkin, Victoria; Léveillé, Richard; Marchand, Geneviève; Sobrón Sánchez, Pablo; Favot, Laurent; Cody, George; Steele, Andrew; Flückiger, Lorenzo; Lees, David; Nefian, Ara; Martin, Mildred; Gailhanou, Marc; Westall, Frances; Israël, Guy; Agard, Christophe; Baroukh, Julien; Donny, Christophe; Gaboriaud, Alain; Guillemot, Philippe; Lafaille, Vivian; Lorigny, Eric; Paillet, Alexis; Pérez, René; Saccoccio, Muriel; Yana, Charles; Aparicio, Carlos Armiens; Caride Rodríguez, Javier; Carrasco Blázquez, Isaías; Gómez Gómez, Felipe; Elvira, Javier Gómez; Hettrich, Sebastian; Lepinette Malvitte, Alain; Marín Jiménez, Mercedes; Frías, Jesús Martínez; Soler, Javier Martín; Torres, F. Javier Martín; Molina Jurado, Antonio; Sotomayor, Luis Mora; Muñoz Caro, Guillermo; Navarro López, Sara; González, Verónica Peinado; García, Jorge Pla; Rodriguez Manfredi, José Antonio; Planelló, Julio José Romeral; Alejandra Sans Fuentes, Sara; Sebastian Martinez, Eduardo; Torres Redondo, Josefina; O'Callaghan, Roser Urqui; Zorzano Mier, María-Paz; Chipera, Steve; Lacour, Jean-Luc; Mauchien, Patrick; Sirven, Jean-Baptiste; Manning, Heidi; Fairén, Alberto; Hayes, Alexander; Joseph, Jonathan; Squyres, Steven; Thomas, Peter; Dupont, Audrey; Lundberg, Angela; Melikechi, Noureddine; Mezzacappa, Alissa; DeMarines, Julia; Grinspoon, David; Reitz, Günther; Prats, Benito; Atlaskin, Evgeny; Genzer, Maria; Harri, Ari-Matti; Haukka, Harri; Kahanpää, Henrik; Kauhanen, Janne; Paton, Mark; Polkko, Jouni; Schmidt, Walter; Siili, Tero; Fabre, Cécile; Wray, James; Wilhelm, Mary Beth; Poitrasson, Franck; Patel, Kiran; Gorevan, Stephen; Indyk, Stephen; Paulsen, Gale; Bish, David; Schieber, Juergen; Gondet, Brigitte; Langevin, Yves; Geffroy, Claude; Baratoux, David; Berger, Gilles; Cros, Alain; Uston, Claude d.; Lasue, Jérémie; Lee, Qiu-Mei; Meslin, Pierre-Yves; Pallier, Etienne; Parot, Yann; Pinet, Patrick; Schröder, Susanne; Toplis, Mike; Lewin, Éric; Brunner, Will; Heydari, Ezat; Achilles, Cherie; Oehler, Dorothy; Sutter, Brad; Cabane, Michel; Coscia, David; Szopa, Cyril; Robert, François; Sautter, Violaine; Nachon, Marion; Buch, Arnaud; Stalport, Fabien; Coll, Patrice; François, Pascaline; Raulin, François; Teinturier, Samuel; Cameron, James; Clegg, Sam; Cousin, Agnès; DeLapp, Dorothea; Dingler, Robert; Jackson, Ryan Steele; Johnstone, Stephen; Lanza, Nina; Little, Cynthia; Nelson, Tony; Williams, Richard B.; Jones, Andrea; Kirkland, Laurel; Treiman, Allan; Baker, Burt; Cantor, Bruce; Caplinger, Michael; Davis, Scott; Duston, Brian; Fay, Donald; Hardgrove, Craig; Harker, David; Herrera, Paul; Jensen, Elsa; Kennedy, Megan R.; Krezoski, Gillian; Krysak, Daniel; Lipkaman, Leslie; McCartney, Elaina; McNair, Sean; Nixon, Brian; Posiolova, Liliya; Ravine, Michael; Salamon, Andrew; Saper, Lee; Stoiber, Kevin; Supulver, Kimberley; Van Beek, Jason; Zimdar, Robert; French, Katherine Louise; Iagnemma, Karl; Miller, Kristen; Summons, Roger; Goesmann, Fred; Hviid, Stubbe; Johnson, Micah; Lefavor, Matthew; Lyness, Eric; Breves, Elly; Dyar, M. Darby; Fassett, Caleb; Blake, David F.; Bristow, Thomas; DesMarais, David; Edwards, Laurence; Haberle, Robert; Hoehler, Tori; Hollingsworth, Jeff; Kahre, Melinda; Keely, Leslie; McKay, Christopher; Bleacher, Lora; Brinckerhoff, William; Choi, David; Conrad, Pamela; Dworkin, Jason P.; Eigenbrode, Jennifer; Floyd, Melissa; Freissinet, Caroline; Garvin, James; Glavin, Daniel; Harpold, Daniel; Mahaffy, Paul; Martin, David K.; McAdam, Amy; Pavlov, Alexander; Raaen, Eric; Smith, Michael D.; Stern, Jennifer; Tan, Florence; Trainer, Melissa; Meyer, Michael; Posner, Arik; Voytek, Mary; Anderson, Robert C.; Aubrey, Andrew; Beegle, Luther W.; Behar, Alberto; Brinza, David; Calef, Fred; Christensen, Lance; Crisp, Joy A.; DeFlores, Lauren; Feldman, Jason; Feldman, Sabrina; Flesch, Gregory; Hurowitz, Joel; Jun, Insoo; Keymeulen, Didier; Maki, Justin; Mischna, Michael; Morookian, John Michael; Parker, Timothy; Pavri, Betina; Schoppers, Marcel; Sengstacken, Aaron; Simmonds, John J.; Spanovich, Nicole; de la Torre Juarez, Manuel; Vasavada, Ashwin R.; Webster, Christopher R.; Yen, Albert; Archer, Paul Douglas; Cucinotta, Francis; Jones, John H.; Ming, Douglas; Morris, Richard V.; Niles, Paul; Rampe, Elizabeth; Nolan, Thomas; Fisk, Martin; Radziemski, Leon; Barraclough, Bruce; Bender, Steve; Berman, Daniel; Dobrea, Eldar Noe; Tokar, Robert; Vaniman, David; Leshin, Laurie; Cleghorn, Timothy; Huntress, Wesley; Manhès, Gérard; Hudgins, Judy; Olson, Timothy; Stewart, Noel; Sarrazin, Philippe; Grant, John; Vicenzi, Edward; Wilson, Sharon A.; Bullock, Mark; Ehresmann, Bent; Hamilton, Victoria; Hassler, Donald; Peterson, Joseph; Rafkin, Scot; Zeitlin, Cary; Fedosov, Fedor; Golovin, Dmitry; Karpushkina, Natalya; Kozyrev, Alexander; Litvak, Maxim; Malakhov, Alexey; Mitrofanov, Igor; Mokrousov, Maxim; Nikiforov, Sergey; Prokhorov, Vasily; Sanin, Anton; Tretyakov, Vladislav; Varenikov, Alexey; Vostrukhin, Andrey; Kuzmin, Ruslan; Clark, Benton; Wolff, Michael; McLennan, Scott; Botta, Oliver; Drake, Darrell; Bean, Keri; Lemmon, Mark; Lee, Ella Mae; Sucharski, Robert; Hernández, Miguel Ángel de Pablo; Blanco Ávalos, Juan José; Ramos, Miguel; Kim, Myung-Hee; Malespin, Charles; Plante, Ianik; Muller, Jan-Peter; González, Rafael Navarro; Ewing, Ryan; Boynton, William; Downs, Robert; Fitzgibbon, Mike; Harshman, Karl; Morrison, Shaunna; Kortmann, Onno; Williams, Amy; Lugmair, Günter; Wilson, Michael A.; Jakosky, Bruce; Zunic, Tonci Balic; Frydenvang, Jens; Kinch, Kjartan; Stipp, Susan Louise Svane; Boyd, Nick; Campbell, John L.; Gellert, Ralf; Perrett, Glynis; Pradler, Irina; VanBommel, Scott; Jacob, Samantha; Owen, Tobias; Rowland, Scott; Savijärvi, Hannu; Boehm, Eckart; Böttcher, Stephan; Burmeister, Sönke; Guo, Jingnan; Köhler, Jan; García, César Martín; Mellin, Reinhold Mueller; Schweingruber, Robert Wimmer; McConnochie, Timothy; Benna, Mehdi; Franz, Heather; Bower, Hannah; Brunner, Anna; Blau, Hannah; Boucher, Thomas; Carmosino, Marco; Atreya, Sushil; Elliott, Harvey; Halleaux, Douglas; Rennó, Nilton; Wong, Michael; Pepin, Robert; Elliott, Beverley; Spray, John; Thompson, Lucy; Gordon, Suzanne; Williams, Joshua; Vasconcelos, Paulo; Bentz, Jennifer; Nealson, Kenneth; Popa, Radu; Moersch, Jeffrey; Tate, Christopher; Day, Mackenzie; Kocurek, Gary; Hallet, Bernard; Sletten, Ronald; Francis, Raymond; McCullough, Emily; Cloutis, Ed; ten Kate, Inge Loes; Arvidson, Raymond; Fraeman, Abigail; Scholes, Daniel; Slavney, Susan; Stein, Thomas; Ward, Jennifer; Berger, Jeffrey; Moores, John E.

    2013-05-01

    Observations by the Mars Science Laboratory Mast Camera (Mastcam) in Gale crater reveal isolated outcrops of cemented pebbles (2 to 40 millimeters in diameter) and sand grains with textures typical of fluvial sedimentary conglomerates. Rounded pebbles in the conglomerates indicate substantial fluvial abrasion. ChemCam emission spectra at one outcrop show a predominantly feldspathic composition, consistent with minimal aqueous alteration of sediments. Sediment was mobilized in ancient water flows that likely exceeded the threshold conditions (depth 0.03 to 0.9 meter, average velocity 0.20 to 0.75 meter per second) required to transport the pebbles. Climate conditions at the time sediment was transported must have differed substantially from the cold, hyper-arid modern environment to permit aqueous flows across several kilometers.

  18. Rock spatial densities on the rims of the Tycho secondary craters in Mare Nectaris

    Science.gov (United States)

    Basilevsky, A. T.; Michael, G. G.; Kozlova, N. A.

    2018-04-01

    The aim of this work is to check whether the technique of estimation of age of small lunar craters based on spatial density of rock boulders on their rims described in Basilevsky et al. (2013, 2015b) and Li et al. (2017) for the craters work presents the rock counts on the rims of four craters having diameters 1000, 1100, 1240 and 1400 m located in Mare Nectaris. These craters are secondaries of the primary crater Tycho, whose age was found to be 109 ± 4 Ma (Stoffler and Ryder, 2001) so this may be taken as the age of the four craters, too. Using the dependence of the rock spatial densities at the crater rims on the crater age for the case of mare craters (Li et al., 2017) our measured rock densities correspond to ages from ∼100 to 130 Ma. These estimates are reasonably close to the given age of the primary crater Tycho. This, in turn, suggests that this technique of crater age estimation is applicable to craters up to ∼1.5 km in diameter. For the four considered craters we also measured their depth/diameter ratios and the maximum angles of the crater inner slopes. For the considered craters it was found that with increasing crater diameter, the depth/diameter ratios and maximum angles of internal slopes increase, but the values of these parameters for specific craters may deviate significantly from the general trends. The deviations probably result from some dissimilarities in the primary crater geometries, that may be due to crater to crater differences in characteristics of impactors (e.g., in their bulk densities) and/or differences in the mechanical properties of the target. It may be possible to find secondaries of crater Tycho in the South pole area and, if so, they may be studied to check the specifics and rates of the rock boulder degradation in the lunar polar environment.

  19. Effects of probiotics on the faecal production of hydrogen and methane in patients with meteorism

    DEFF Research Database (Denmark)

    Schrøder, Julie Bernstorf; Jespersen, Lene; Westermann, Peter

    Meteorism is a dominating problem in the western world, especially in women. The condition is very difficult to quantify, and effective and documented therapies are not avaiable. We wanted to develop a method for measuring anaerobic production of hydrogen and methane in faeces, and to correlate t...

  20. Dynamical modeling validation of parent bodies associated with newly discovered CMN meteor showers

    Czech Academy of Sciences Publication Activity Database

    Šegon, D.; Vaubaillon, J.; Gural, P.S.; Vida, D.; Andreić, Z.; Korlević, K.; Skokić, Ivica

    2017-01-01

    Roč. 598, February (2017), A15/1-A15/13 E-ISSN 1432-0746 Institutional support: RVO:67985815 Keywords : meteorites * meteors * meteoroids Subject RIV: BN - Astronomy , Celestial Mechanics, Astrophysics OBOR OECD: Astronomy (including astrophysics,space science) Impact factor: 5.014, year: 2016

  1. The beginning heights and light curves of high-altitude meteors

    Czech Academy of Sciences Publication Activity Database

    Koten, Pavel; Spurný, Pavel; Borovička, Jiří; Evans, S.; Elliott, A.; Betlem, H.; Štork, Rostislav; Jobse, K.

    2006-01-01

    Roč. 41, č. 9 (2006), s. 1305-1320 ISSN 1086-9379 R&D Projects: GA ČR GP205/02/P038 Institutional research plan: CEZ:AV0Z10030501 Keywords : bright Leonid meteors * atmospheric trajectories Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 2.524, year: 2006

  2. Double station observation of Draconid meteor outburst from two moving aircraft

    Science.gov (United States)

    Koten, Pavel; Vaubaillon, Jeremie; Margonis, Anastasios; Tóth, Juraj; Ďuriš, František; McAulliffe, Jonathan; Oberst, Jürgen

    2015-12-01

    A Draconid meteor shower outburst was observed from the boards of two scientific aircraft on 8 October 2011. In this paper we report the results of this double station experiment. The beginning and terminal heights are similar to other Draconid observations and confirm the fragile nature of the meteoroids. From the distribution function of terminal heights, a critical mass was found to be about 3.5 g. A behaviour of the terminal heights changes at this point. Light curves of Draconid meteors show great variability with a maximum of the F-number distribution around 0.35, which also confirms fragility of the material. Observed radiants of the meteors are in agreement with the theoretical model. Although encounters with two different filaments were predicted, it is impossible to distinguish between them from the radiants as well as the orbital data. Despite the complications with the data processing the airborne mission shows that such double station experiment is possible and provides valuable insight into meteor structure and dynamics.

  3. Detection of a persistent meteoric metal layer in the Martian atmosphere

    Science.gov (United States)

    Crismani, M. M. J.; Schneider, N. M.; Plane, J. M. C.; Evans, J. S.; Jain, S. K.; Chaffin, M. S.; Carrillo-Sanchez, J. D.; Deighan, J. I.; Yelle, R. V.; Stewart, A. I. F.; McClintock, W.; Clarke, J.; Holsclaw, G. M.; Stiepen, A.; Montmessin, F.; Jakosky, B. M.

    2017-06-01

    Interplanetary dust particles sporadically enter planetary atmospheres at orbital velocities and ablate as collisions occur with ambient gases to produce a persistent layer of metallic atoms (for example, Fe, Mg, Na) in their upper atmospheres. Such layers are well studied at Earth, but have not been directly detected elsewhere in the Solar System. Here we report the detection of a meteoric layer consisting of Mg+ ions near an altitude of 90 km in the Martian atmosphere from ultraviolet remote sensing observations by NASA's MAVEN spacecraft. We observe temporal variability in the Mg+ layer over the course of a Martian year, moving up and down in altitude seasonally and in response to dust storms, and displaying diurnal fluctuations in density. We also find that most meteor showers do not significantly perturb this layer, which constrains the fluence of eleven observed Martian meteor showers to less than our estimated global dust flux. The persistence and variability of the Mg+ layer are difficult to explain with existing models and reconcile with other transient layers of ions observed in the Martian ionosphere. We suggest that the transient layers are not sourced from the persistent Mg+ layer and thus not derived from meteoric material, but are ambient ions produced by some unknown mechanism.

  4. Meteoric precipitation at Yucca Mountain, Nevada: Chemical and stable isotope analyses, 2006-09

    Science.gov (United States)

    Moscati, Richard J.; Scofield, Kevin M.

    2011-01-01

    Meteoric precipitation samples collected in 2006-09 at Yucca Mountain, Nevada, were analyzed for chemistry and stable isotope composition. Precipitation is the major source of infiltration to the unsaturated zone and of recharge to the saturated zone at Yucca Mountain.

  5. An analysis of the physical, chemical, optical, and historical impacts of the 1908 Tunguska meteor fall

    Science.gov (United States)

    Turco, R. P.; Toon, O. B.; Park, C.; Whitten, R. C.; Pollack, J. B.; Noerdlinger, P.

    1982-01-01

    An analysis is presented of the physical characteristics and photochemical aftereffects of the 1908 Tunguska explosive cometary meteor, whose physical manifestations are consistent with a five million ton object's entry into the earth's atmosphere at 40 km/sec. Aerodynamic calculations indicate that the shock waves emanating from the falling meteor could have generated up to 30 million tons of nitric oxide in the stratosphere and mesosphere. A fully interactive one-dimensional chemical-kinetics model of atmospheric trace constituents is used to estimate the photochemical consequences of such a large NO injection. The 35-45% hemispherical ozone depletion predicted by the model is in keeping with the 30 + or - 15% ozone variation reported for the first year after the Tunguska fall. Attention is also given to the optical anomalies which followed the event for indications of NO(x)-O(x) chemiluminescent emissions, NO2 solar absorption, and meteoric dust turbidity, along with possible climate changes due to the nearly one million tons of pulverized dust deposited in the mesosphere and stratosphere by the meteor.

  6. The New Meteor Radar at Penn State: Design and First Observations

    Science.gov (United States)

    Urbina, J.; Seal, R.; Dyrud, L.

    2011-01-01

    In an effort to provide new and improved meteor radar sensing capabilities, Penn State has been developing advanced instruments and technologies for future meteor radars, with primary objectives of making such instruments more capable and more cost effective in order to study the basic properties of the global meteor flux, such as average mass, velocity, and chemical composition. Using low-cost field programmable gate arrays (FPGAs), combined with open source software tools, we describe a design methodology enabling one to develop state-of-the art radar instrumentation, by developing a generalized instrumentation core that can be customized using specialized output stage hardware. Furthermore, using object-oriented programming (OOP) techniques and open-source tools, we illustrate a technique to provide a cost-effective, generalized software framework to uniquely define an instrument s functionality through a customizable interface, implemented by the designer. The new instrument is intended to provide instantaneous profiles of atmospheric parameters and climatology on a daily basis throughout the year. An overview of the instrument design concepts and some of the emerging technologies developed for this meteor radar are presented.

  7. Long-Term Continuous Double Station Observation of Faint Meteor Showers

    Czech Academy of Sciences Publication Activity Database

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

    2016-01-01

    Roč. 16, č. 9 (2016), 1493/1-1493/10 ISSN 1424-8220 R&D Projects: GA ČR GA14-25251S Institutional support: RVO:67985815 Keywords : faint meteor shower * meteoroid * CCD camera Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 2.677, year: 2016

  8. Effects of probiotics on the faecal production of hydrogen and methane in patients with meteorism

    DEFF Research Database (Denmark)

    Schrøder, Julie Bernstorf; Jespersen, Lene; Westermann, Peter

    Meteorism is a dominating problem in the western world, especially in women. The condition is very difficult to quantify, and effective and documented therapies are not avaiable. We wanted to develop a method for measuring anaerobic production of hydrogen and methane in faeces, and to correlate...

  9. ''Meteor 2'' programme for calculation of environment irradiation under nuclear power plant normal operating conditions

    International Nuclear Information System (INIS)

    Oppermann, R.; Kryuger, F.V.; Prior, Kh.

    1976-01-01

    A ''Meteor 2'' program developed for the BESM-6 electronic computer is described. The program permits to estimate radiation effect under nuclear power plant normal operation conditions. The calculations are carried out depending on the quantity and composition of the release activity, a ventilating pipe height, meteorological conditions as well as taking into account radioactive substance decay. The program permits to calculate the following values in the vicinity of radioactive product release point: a local distribution of a mean dose spread factor; a local distribution of a mean dose of inhalation irradiation for various human organs (the whole body, thyroid gland, bones, alimentary canal, lungs) and separate population groups; a local distribution of a mean dose of external beta radiation; a local distribution of a mean dose of external gamma radiation. The program includes the main ''Meteor'' program and 3 subprograms of DOBER, DABER and DABOR and is written in the FORTRAN language. The ''Meteor'' program organizes the data input and output of some separate subprograms. The DOBER subprogram determines the spread factor, the inhalation irradiation dose for separate organs and the external beta radiation dose. The DABER subprogram determines the external gamma radiation dose in the approximation of homogeneous distribution of a source in the vicinity of the calculation point. The DABOR subprogram is the second program for the calculating the external irradiation dose. The examples of using the ''Meteor'' program are given [ru

  10. MU head echo observations of the 2010 Geminids: radiant, orbit, and meteor flux observing biases

    Directory of Open Access Journals (Sweden)

    J. Kero

    2013-03-01

    Full Text Available We report Geminid meteor head echo observations with the high-power large-aperture (HPLA Shigaraki middle and upper atmosphere (MU radar in Japan (34.85° N, 136.10° E. The MU radar observation campaign was conducted from 13 December 2010, 08:00 UTC to 15 December, 20:00 UTC and resulted in 48 h of radar data. A total of ~ 270 Geminids were observed among ~ 8800 meteor head echoes with precisely determined orbits. The Geminid head echo activity is consistent with an earlier peak than the visual Geminid activity determined by the International Meteor Organization (IMO. The observed flux of Geminids is a factor of ~ 3 lower than the previously reported flux of the 2009 Orionids measured with an identical MU~radar setup. We use the observed flux ratio to discuss the relation between the head echo mass–velocity selection effect, the mass distribution indices of meteor showers and the mass threshold of the MU radar.

  11. Comparing eyewitness-derived trajectories of bright meteors to instrumentally-observed data

    Science.gov (United States)

    Moser, D. E.

    2017-09-01

    The NASA Meteoroid Environment Office (MEO) is often called upon to analyze meteors of public interest observed over the United States. Data from meteor networks are often utilized to accomplish this, as are recordings from the general public. When these methods fail, eyewitness reports are the only resource which can be leveraged. The MEO developed a tool to crudely calculate the trajectories of bright meteors from the eyewitness reports submitted to the American Meteor Society. The tool was tested on eyewitness data for 33 cases and compared to observed data from the NASA All Sky Fireball Network. The tool performed better for cases with more than 75 eyewitness reports than those with fewer than 75, by almost a factor of two across all metrics except for the end height. For these cases, the eyewitness-derived trajectory was about 50 km from the observed trajectory, the radiant was within 15°, and the speed was within 20% of that observed on average. A description of the tool, example case studies, and general trends are described.

  12. Curiosity's field site in Gale Crater, Mars, in context

    Science.gov (United States)

    Edgett, K. S.; Malin, M. C.

    2011-12-01

    NASA's Mars rover, Curiosity, is anticipated to land in Gale Crater in August 2012. Gale is a 155 km-diameter impact crater adjacent to the ancient crustal "north-south dichotomy boundary." It contains a mound of layered rock (of yet-unknown proportions of clastic sediment, tephra, and chemical precipitates) ˜5 km-high that was eroded by fluvial, eolian, and mass-movement processes. The stratigraphy includes erosional unconformities representing periods when new impact craters formed and streams cut canyons into layered rock. The majority of known impact sites on Earth are craters that were filled and buried in sediment; examples occur under the Chesapeake Bay and beneath the Chicago O'Hare Airport. The upper crust of Mars, with its relative lack of tectonism, is almost entirely a layered, cratered volume of filled, buried, and complexly-interbedded craters and fluvial systems. Some of these have been exhumed or partly exhumed; some, like Gale, were once filled with extensive rock layers that were eroded to form mounds or mesas. Landforms all across Arabia Terra show that similar materials were also deposited between craters. Gale is of the family of Mars craters that were filled and buried (or nearly so). The highest elevation on the Gale mound exceeds the crater's north rim by ˜2 km and is within 500 m of the highest point on the south rim. Many similar craters occur in Arabia Terra; these are instructive as some contain mounds, others have mesas or buttes or other erosional expressions. Craters within 10s to a few 100s of km of each other typically contain very different materials, as exhibited by varied erosional expression, bedding style, and layer thickness. This suggests that the depositional environments, sources, and physical properties of the deposited material differed from place to place and time to time, even in neighboring settings. The Curiosity site in Gale has the potential to illuminate processes that acted locally and globally on early Mars. In

  13. Observations of meteor-head echoes using the Jicamarca 50MHz radar in interferometer mode

    Directory of Open Access Journals (Sweden)

    J. L. Chau

    2004-01-01

    Full Text Available We present results of recent observations of meteor-head echoes obtained with the high-power large-aperture Jicamarca 50MHz radar (11.95°S, 76.87°W in an interferometric mode. The large power-aperture of the system allows us to record more than 3000 meteors per hour in the small volume subtended by the 1° antenna beam, albeit when the cluttering equatorial electrojet (EEJ echoes are not present or are very weak. The interferometry arrangement allows the determination of the radiant (trajectory and speed of each meteor. It is found that the radiant distribution of all detected meteors is concentrated in relative small angles centered around the Earth's Apex as it transits over the Jicamarca sky, i.e. around the corresponding Earth heading for the particular observational day and time, for all seasons observed so far. The dispersion around the Apex is ~18° in a direction transverse to the Ecliptic plane and only 8.5° in heliocentric longitude in the Ecliptic plane both in the Earth inertial frame of reference. No appreciable interannual variability has been observed. Moreover, no population related to the optical (larger meteors Leonid showers of 1998-2002 is found, in agreement with other large power-aperture radar observations. A novel cross-correlation detection technique (adaptive match-filtering is used in combination with a 13 baud Barker phase-code. The technique allows us to get good range resolution (0.75km without any sensitivity deterioration for the same average power, compared to the non-coded long pulse scheme used at other radars. The matching Doppler shift provides an estimation of the velocity within a pulse with the same accuracy as if a non-coded pulse of the same length had been used. The velocity distribution of the meteors is relatively narrow and centered around 60kms-1. Therefore most of the meteors have an almost circular retrograde orbit around the Sun. Less than 8% of the velocities correspond to interstellar orbits

  14. The challenge associated with the robust computation of meteor velocities from video and photographic records

    Science.gov (United States)

    Egal, A.; Gural, P. S.; Vaubaillon, J.; Colas, F.; Thuillot, W.

    2017-09-01

    The CABERNET project was designed to push the limits for obtaining accurate measurements of meteoroids orbits from photographic and video meteor camera recordings. The discrepancy between the measured and theoretic orbits of these objects heavily depends on the semi-major axis determination, and thus on the reliability of the pre-atmospheric velocity computation. With a spatial resolution of 0.01° per pixel and a temporal resolution of up to 10 ms, CABERNET should be able to provide accurate measurements of velocities and trajectories of meteors. To achieve this, it is necessary to improve the precision of the data reduction processes, and especially the determination of the meteor's velocity. In this work, most of the steps of the velocity computation are thoroughly investigated in order to reduce the uncertainties and error contributions at each stage of the reduction process. The accuracy of the measurement of meteor centroids is established and results in a precision of 0.09 pixels for CABERNET, which corresponds to 3.24‧‧. Several methods to compute the velocity were investigated based on the trajectory determination algorithms described in Ceplecha (1987) and Borovicka (1990), as well as the multi-parameter fitting (MPF) method proposed by Gural (2012). In the case of the MPF, many optimization methods were implemented in order to find the most efficient and robust technique to solve the minimization problem. The entire data reduction process is assessed using simulated meteors, with different geometrical configurations and deceleration behaviors. It is shown that the multi-parameter fitting method proposed by Gural(2012)is the most accurate method to compute the pre-atmospheric velocity in all circumstances. Many techniques that assume constant velocity at the beginning of the path as derived from the trajectory determination using Ceplecha (1987) or Borovicka (1990) can lead to large errors for decelerating meteors. The MPF technique also allows one to

  15. 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

  16. Morphometry and Morphology of Fresh Craters on Titan

    Science.gov (United States)

    Kirk, R. L.; Wood, C. A.; Neish, C.; Lucas, A.; Hayes, A. G.; Cassini Radar Team

    2011-12-01

    Cassini RADAR imagery obtained on Titan flyby T77 revealed a 40-km diameter fresh impact crater at 11.6° N 44.6° W. This is only the 8th crater identified with high confidence (Wood et al., 2010, Icarus 206, 334), and the 3rd (after Sinlap D=79 km and Ksa D=30 km) for which the depth can be estimated by comparing the foreshortening of the near and far walls. This "autostereo" technique yields an estimated depth of 680 m. The T77 image forms a stereo pair with the T17 discovery image of Ksa from which we estimate the depth of Ksa at 750-800 m, in close agreement with SARTopo data. The depth of Sinlap is 760 m based on SARTopo. Depth-diameter ratios for these craters thus range from 0.01 to 0.025 and the depths are comparable to but 200-400 m shallower than fresh craters of the same size on Ganymede (Bray et al., 2008, Met. Planet Sci. 43, 1979). The depth differences could be explained by initial crater morphometry, by relaxation in a different thermal environment, or (perhaps most plausibly given the bland floors of even the freshest Titan craters) to sedimentary infill. In contrast, the 18x36 km elliptical depression at Sotra Facula is much deeper than Ganymede craters of similar size (d=1500 m from stereo), supporting the conclusion that it is not an impact crater. All three craters exhibit a relatively radar-bright annulus around the outer edge of the floor, possibly as the result of mass wasting of blocky materials from the crater walls. The central part of each crater is darker. The central darker floor of the new crater is symmetrical and featureless, whereas Ksa has a bright central ring 7 km in diameter. Stereo spot heights indicate the ring is 350±100 m above the outer floor. This height is in close agreement with the scaling for Ganymede crater central peaks from Bray et al. (2008). The darker floor area of Sinlap is substantially asymmetrical with a small bright central spot whose elevation is unknown. The new crater has continuous, radar

  17. Compound maar crater and co-eruptive scoria cone in the Lunar Crater Volcanic Field (Nevada, USA)

    Science.gov (United States)

    Amin, Jamal; Valentine, Greg A.

    2017-06-01

    Bea's Crater (Lunar Crater Volcanic Field, Nevada, USA) consists of two coalesced maar craters with diameters of 440 m and 1050 m, combined with a co-eruptive scoria cone that straddles the northeast rim of the larger crater. The two craters and the cone form an alignment that parallels many local and regional structures such as normal faults, and is interpreted to represent the orientation of the feeder dyke near the surface. The maar formed among a dense cluster of scoria cones; the cone-cluster topography resulted in crater rim that has a variable elevation. These older cones are composed of variably welded agglomerate and scoria with differing competence that subsequently affected the shape of Bea's Crater. Tephra ring deposits associated with phreatomagmatic maar-forming eruptions are rich in basaltic lithics derived from clasts, consistent with ejection from relatively shallow explosions although a diatreme might extend to deeper levels beneath the maar. Interbedding of deposits on the northeastern cone and in the tephra ring record variations in the magmatic volatile driven and phreatomagmatic eruption styles in both space and time along a feeder dike.

  18. Craters and basins on Ganymede and Callisto - Morphological indicators of crustal evolution

    Science.gov (United States)

    Passey, Q. R.; Shoemaker, E. M.

    The morphologic characteristics of craters and palimpsests on Ganymede and Callisto are surveyed, and the crustal properties of these satellites and the evolution of the properties are studied. The morphology of bowl-shaped craters, smooth-floored craters, craters without central peaks, craters with central pits, chain craters on Callisto, the Gilgamesh and Western Equatorial Basins on Ganymede, crater palimpsests and penepalimpsests, multiring structures on Callisto, and the Galileo Regio rimmed furrow system on Ganymede are described individually. The crustal evolution is addressed by examining the development of the Galileo Regio system, the distribution of crater retention ages, the record of ray clusters, the thermal history of the lithosphere of Ganymede, and the origin of the central pits. It is suggested that as the lithosphere of each satellite cooled and thickened, crater retentivity spread as a wave from the polar regions and the antapex toward the apex; at any given location, progressively larger craters were retained with the passage of time.

  19. Craters and basins on Ganymede and Callisto - Morphological indicators of crustal evolution

    Science.gov (United States)

    Passey, Q. R.; Shoemaker, E. M.

    1982-01-01

    The morphologic characteristics of craters and palimpsests on Ganymede and Callisto are surveyed, and the crustal properties of these satellites and the evolution of the properties are studied. The morphology of bowl-shaped craters, smooth-floored craters, craters without central peaks, craters with central pits, chain craters on Callisto, the Gilgamesh and Western Equatorial Basins on Ganymede, crater palimpsests and penepalimpsests, multiring structures on Callisto, and the Galileo Regio rimmed furrow system on Ganymede are described individually. The crustal evolution is addressed by examining the development of the Galileo Regio system, the distribution of crater retention ages, the record of ray clusters, the thermal history of the lithosphere of Ganymede, and the origin of the central pits. It is suggested that as the lithosphere of each satellite cooled and thickened, crater retentivity spread as a wave from the polar regions and the antapex toward the apex; at any given location, progressively larger craters were retained with the passage of time.

  20. Meteor head echo polarization at 930 MHz studied with the EISCAT UHF HPLA radar

    Directory of Open Access Journals (Sweden)

    G. Wannberg

    2011-06-01

    Full Text Available The polarization characteristics of 930-MHz meteor head echoes have been studied for the first time, using data obtained in a series of radar measurements carried out with the tristatic EISCAT UHF high power, large aperture (HPLA radar system in October 2009. An analysis of 44 tri-static head echo events shows that the polarization of the echo signal recorded by the Kiruna receiver often fluctuates strongly on time scales of tens of microseconds, illustrating that the scattering process is essentially stochastic. On longer timescales (> milliseconds, more than 90 % of the recorded events show an average polarization signature that is independent of meteor direction of arrival and echo strength and equal to that of an incoherent-scatter return from underdense plasma filling the tristatic observation volume. This shows that the head echo plasma targets scatter isotropically, which in turn implies that they are much smaller than the 33-cm wavelength and close to spherically symmetric, in very good agreement with results from a previous EISCAT UHF study of the head echo RCS/meteor angle-of-incidence relationship. Significant polarization is present in only three events with unique target trajectories. These all show a larger effective target cross section transverse to the trajectory than parallel to it. We propose that the observed polarization may be a signature of a transverse charge separation plasma resonance in the region immediately behind the meteor head, similar to the resonance effects previously discussed in connection with meteor trail echoes by Herlofson, Billam and Browne, Jones and Jones and others.

  1. 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.

  2. 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.

  3. The METEOR initiative: the way forward for optimal, worldwide data integration to improve care for RA patients.

    Science.gov (United States)

    van den Berg, R; van der Heijde, D; Landewé, R; van Lambalgen, K; Huizinga, T

    2014-01-01

    The METEOR (Measurement of Efficacy of Treatment in the 'Era of Outcome' in Rheumatology) initiative aims at improving care for RA patients by assisting rheumatologists in strict monitoring and tight control of disease activity. The state of the art of the METEOR initiative, the technical organisation of the database and future perspectives are described. RA patients are followed in the daily practice setting; (follow-up) visits are registered via the tool or upload facility. The METEOR tool is an easy-to-use, stand-alone, web-based program free available to rheumatologists worldwide. The upload facility is developed to meet the wish of many local registries to upload their data into the METEOR database to benefit from benchmark and research facilities without giving up their own registries. Rheumatologists will always have access to full patient details of their own patients. Yet, patient identifying data are stored in an encrypted manner in the METEOR database in order to provide full patient anonymity to all other users. While the tool can be used without IT involvement, the upload facility requires IT support. The incorporation of local registries into the METEOR database is time consuming, requires endeavours as well as technical support of both the local registries and the METEOR organisation, however, the combination of the tool and the upload facility has enabled the successful creation of a strong research database with real life data of 35,000 RA patients with more than 140,000 visits from all over the world! The METEOR database offers the unique opportunity to study daily practice care as well as dedicated research questions in worldwide real life setting. Moreover, the METEOR's collective experience can be accessed by those who think about initiating patient registries for all sorts of purposes. Consequently, these well-designed registries may help in treating RA patients even more successfully in future.

  4. Sunset Crater Volcano National Monument : Acoustical Monitoring 2010

    Science.gov (United States)

    2013-05-01

    During the summer of 2010 (July - August), the Volpe Center collected baseline acoustical data at Sunset Crater Volcano National Monument (SUCR) at a site deployed for approximately 30 days. The baseline data collected during this period will help pa...

  5. Vegetation damage and recovery after Chiginagak Volcano Crater drainage event

    Data.gov (United States)

    Department of the Interior — From August 20 — 23, 2006, I revisited Chiginigak volcano to document vegetation recovery after the crater drainage event that severely damaged vegetation in May of...

  6. LRO MOON CRATER EDR RAWDATA VERSION 1.0

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set comprises the raw binary data from from the LRO Cosmic Ray Telescope for the Effects of Radiation (CRaTER) instrument. The data consists of the...

  7. Are the Complex Algerian Meteoritic Craters Potential Hydrocarbon Traps?

    Science.gov (United States)

    Belhai, D.; Merle, O.; Vincent, P.; Afalfiz, A.; Devouard, B.

    2005-03-01

    The geological analysis of the meteoritic craters of Tin Bider and Ouarkziz (Sahara, Algeria) reveals identical characters to those of Ava and Viewfield. Their detailed study will make it possible to slice as for the presence or not ofhydrocarbons.

  8. Fractal Dimension of Geologically Constrained Crater Populations of Mercury

    Science.gov (United States)

    Mancinelli, Paolo; Pauselli, Cristina; Perugini, Diego; Lupattelli, Andrea; Federico, Costanzo

    2015-07-01

    Data gathered during the Mariner10 and MESSENGER missions are collated in this paper to classify craters into four geo-chronological units constrained to the geological map produced after MESSENGER's flybys. From the global catalogue, we classify craters, constraining them to the geological information derived from the map. We produce a size frequency distribution (SFD) finding that all crater classes show fractal behaviour: with the number of craters inversely proportional to their diameter, the exponent of the SFD (i.e., the fractal dimension of each class) shows a variation among classes. We discuss this observation as possibly being caused by endogenic and/or exogenic phenomena. Finally, we produce an interpretative scenario where, assuming a constant flux of impactors, the slope variation could be representative of rheological changes in the target materials.

  9. Mars Climate History: Insights From Impact Crater Wall Slope Statistics

    Science.gov (United States)

    Kreslavsky, Mikhail A.; Head, James W.

    2018-02-01

    We use the global distribution of the steepest slopes on crater walls derived from Mars Orbiter Laser Altimeter profile data to assess the magnitudes of degradational processes with latitude, altitude, and time. We independently confirm that Amazonian polar/high-latitude crater slope modification is substantial, but that craters in the low latitudes have essentially escaped significant slope modification since the Early Hesperian. We find that the total amount of crater wall degradation in the Late Noachian is very small in comparison to the circumpolar regions in the Late Amazonian, an observation that we interpret to mean that the Late Noachian climate was not characterized by persistent and continuous warm and wet conditions. A confirmed elevational zonality in degradation in the Early Hesperian is interpreted to mean that the atmosphere was denser than today.

  10. Extreme Access & Lunar Ice Mining in Permanently Shadowed Craters

    Data.gov (United States)

    National Aeronautics and Space Administration — Results from the recent NASA Lunar CRater Observation and Sensing Satellite, or LCROSS, mission in 2010, indicate that water (H2O), ice and other useful volatiles...

  11. A global catalogue of Ceres impact craters ≥ 1 km and preliminary analysis

    Science.gov (United States)

    Gou, Sheng; Yue, Zongyu; Di, Kaichang; Liu, Zhaoqin

    2018-03-01

    The orbital data products of Ceres, including global LAMO image mosaic and global HAMO DTM with a resolution of 35 m/pixel and 135 m/pixel respectively, are utilized in this research to create a global catalogue of impact craters with diameter ≥ 1 km, and their morphometric parameters are calculated. Statistics shows: (1) There are 29,219 craters in the catalogue, and the craters have a various morphologies, e.g., polygonal crater, floor fractured crater, complex crater with central peak, etc.; (2) The identifiable smallest crater size is extended to 1 km and the crater numbers have been updated when compared with the crater catalogue (D ≥ 20 km) released by the Dawn Science Team; (3) The d/D ratios for fresh simple craters, obviously degraded simple crater and polygonal simple crater are 0.11 ± 0.04, 0.05 ± 0.04 and 0.14 ± 0.02 respectively. (4) The d/D ratios for non-polygonal complex crater and polygonal complex crater are 0.08 ± 0.04 and 0.09 ± 0.03. The global crater catalogue created in this work can be further applied to many other scientific researches, such as comparing d/D with other bodies, inferring subsurface properties, determining surface age, and estimating average erosion rate.

  12. Finite element models of non-Newtonian crater relaxation

    Science.gov (United States)

    Thomas, Paul J.; Schubert, Gerald

    1987-01-01

    The effects of a non-Newtonian rheology on the profiles of relaxing craters (such as those seen on the surfaces of the icy Galilean and Saturnian satellites) were studied. Two-dimensional finite element simulations of non-Newtonian viscous flow were performed, and the results were compared with those associated with Newtonian rheology. Viscous relaxation of craters in a non-Newtonian medium was significantly different from that in a Newtonian medium. Crater rims are observed to relax at a more rapid rate in a non-Newtonian region as a result of the movement of the low viscosity region to underneath the crater rim after the initial relaxation of the bowl. Significant differences are also found when central depth is plotted as a function of time. For a Newtonian medium, crater relaxation is exponential in form. In contrast, non-Newtonian crater relaxation is initially rapid, in response to the large initial stresses and small viscosities; however, as stresses decrease, this relaxation becomes extremely gradual.

  13. Morphological indicators of a mascon beneath Ceres' largest crater, Kerwan

    Science.gov (United States)

    Bland, Michael T.; Ermakov, Anton; Raymond, Carol A.; Williams, David A.; Bowling, Tim J.; Preusker, F.; Park, Ryan S.; Marchi, Simone; Castillo-Rogez, Julie C.; Fu, R.R.; Russell, Christopher T.

    2018-01-01

    Gravity data of Ceres returned by the National Aeronautics and Space Administration's Dawn spacecraft is consistent with a lower density crust of variable thickness overlying a higher density mantle. Crustal thickness variations can affect the long‐term, postimpact modification of impact craters on Ceres. Here we show that the unusual morphology of the 280 km diameter crater Kerwan may result from viscous relaxation in an outer layer that thins substantially beneath the crater floor. We propose that such a structure is consistent with either impact‐induced uplift of the high‐density mantle beneath the crater or from volatile loss during the impact event. In either case, the subsurface structure inferred from the crater morphology is superisostatic, and the mass excess would result in a positive Bouguer anomaly beneath the crater, consistent with the highest‐degree gravity data from Dawn. Ceres joins the Moon, Mars, and Mercury in having basin‐associated gravity anomalies, although their origin may differ substantially.

  14. Fractal dimensions of rampart impact craters on Mars

    Science.gov (United States)

    Ching, Delwyn; Taylor, G. Jeffrey; Mouginis-Mark, Peter; Bruno, Barbara C.

    1993-01-01

    Ejecta blanket morphologies of Martian rampart craters may yield important clues to the atmospheric densities during impact, and the nature of target materials (e.g., hard rock, fine-grained sediments, presence of volatiles). In general, the morphologies of such craters suggest emplacement by a fluidized, ground hugging flow instead of ballistic emplacement by dry ejecta. We have quantitatively characterized the shape of the margins of the ejecta blankets of 15 rampart craters using fractal geometry. Our preliminary results suggest that the craters are fractals and are self-similar over scales of approximately 0.1 km to 30 km. Fractal dimensions (a measure of the extent to which a line fills a plane) range from 1.06 to 1.31. No correlations of fractal dimension with target type, elevation, or crater size were observed, though the data base is small. The range in fractal dimension and lack of correlation may be due to a complex interplay of target properties (grain size, volatile content), atmospheric pressure, and crater size. The mere fact that the ejecta margins are fractals, however, indicates that viscosity and yield strength of the ejecta were at least as low as those of basalts, because silicic lava flows are not generally fractals.

  15. 100 New Impact Crater Sites Found on Mars

    Science.gov (United States)

    Kennedy, M. R.; Malin, M. C.

    2009-12-01

    Recent observations constrain the formation of 100 new impact sites on Mars over the past decade; 19 of these were found using the Mars Global Surveyor Mars Orbiter Camera (MOC), and the other 81 have been identified since 2006 using the Mars Reconnaissance Orbiter Context Camera (CTX). Every 6 meter/pixel CTX image is examined upon receipt and, where they overlap images of 0.3-240 m/pixel scale acquired by the same or other Mars-orbiting spacecraft, we look for features that may have changed. New impact sites are initially identified by the presence of a new dark spot or cluster of dark spots in a CTX image. Such spots may be new impact craters, or result from the effect of impact blasts on the dusty surface. In some (generally rare) cases, the crater is sufficiently large to be resolved in the CTX image. In most cases, however, the crater(s) cannot be seen. These are tentatively designated as “candidate” new impact sites, and the CTX team then creates an opportunity for the MRO spacecraft to point its cameras off-nadir and requests that the High Resolution Imaging Science Experiment (HiRISE) team obtain an image of ~0.3 m/pixel to confirm whether a crater or crater cluster is present. It is clear even from cursory examination that the CTX observations are areographically biased to dusty, higher albedo areas on Mars. All but 3 of the 100 new impact sites occur on surfaces with Lambert albedo values in excess of 23.5%. Our initial study of MOC images greatly benefited from the initial global observations made in one month in 1999, creating a baseline date from which we could start counting new craters. The global coverage by MRO Mars Color Imager is more than a factor of 4 poorer in resolution than the MOC Wide Angle camera and does not offer the opportunity for global analysis. Instead, we must rely on partial global coverage and global coverage that has taken years to accumulate; thus we can only treat impact rates statistically. We subdivide the total data

  16. Insights into Meteoric 10Be Dynamics and Climate Stability along the Hawaiian Kohala Climosequence

    Science.gov (United States)

    Dixon, J. L.; Chadwick, O.

    2017-12-01

    We measure meteoric 10Be in soils across a well-studied climate gradient spanning Kohala, Hawaii to provide new understanding of the isotope behavior in soils and constraints on nuclide delivery rates to Earth's surface. Annual rainfall across the Kohala climogradient varies from 16 - 300 cm, with Hawaiian soils reflecting evolution over the past 150 ka, the nominal age of the volcanic parent material. We analyzed a sequence of nine soil profiles for meteoric 10Be and compared with previously measured data on soil chemistry and dust fluxes. In the Kohala system, soil inventories of 10Be span 40-300 x 109 atom/cm2 and generally increase linearly with rainfall, consistent with precipitation-driven fluxes and the high retention of 10Be in clay-rich soil horizons. However, nuclide inventories dramatically decrease for soils at rainfall >140 cm/y. The observed decrease corresponds with other strong changes in weathering intensity across the climate gradient, associated with previously studied and recognized pedogenic thresholds. These thresholds represent abrupt transitions in soil chemistry related to increased throughflow of soil solutions, decreases in base saturation and pH, and the destruction of phyllosilicates and replacement with amorphous oxyhydroxides. Meteoric-derived ages, based on 10Be-flux estimates and measured inventories are uniform for dry soils ( 60ka), but far less than the known substrate age (150ka), indicating that actual delivery rates are lower than predicted from current models in this region. Despite the offset in predicted and substrate ages, the consistency in pattern suggests that the rainfall gradient over the 150 thousand years of soil development has not deviated significantly from its present structure. Furthermore, based on clear 10Be losses in soils with high moisture availability, our results indicate meteoric 10Be may not be a robust tracer of soil age and movement in systems with high rainfall and weathering intensity and low soil

  17. Mesospheric temperatures estimated from the meteor radar observations at Mohe, China

    Science.gov (United States)

    Liu, Libo; Liu, Huixin; Chen, Yiding; Le, Huijun

    2017-04-01

    In this work, we report the estimation of mesospheric temperatures at 90 km height from the observations of the VHF all-sky meteor radar operated at Mohe (53.5 °N, 122.3° E), China, since August 2011. The kinetic temperature profiles retrieved from the observations of Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) onboard the Thermosphere, Ionosphere, Mesosphere, Energetics, and Dynamics (TIMED) satellite are processed to provide the temperature (TSABER) and temperature gradient (dT/dh) at 90 km height. Based on the SABER temperature profile data an empirical dT/dh model is developed for the Mohe latitude. First, we derive the temperatures from the meteor decay times (Tmeteor) and the Mohe dT/dh model gives prior information of temperature gradients. Secondly, the full-width of half maximum (FWHM) of the meteor height profiles is calculated and further used to deduce the temperatures (TFWHM) based on the strong linear relationship between FWHM and TSABER. The temperatures at 90 km deduced from the decay times (Tmeteor) and from the meteor height distributions (TFWHM) at Mohe are validated/calibrated with TSABER. The temperatures present a considerable annual variation, being maximum in winter and minimum in summer. Harmonic analyses reveal that the temperatures have an annual variation consistent with TSABER. Our work suggests that the FWHM has a good performance in routine estimation of the temperatures. It should be pointed out that the slope of FWHM and TSABER is 10.1 at Mohe, which is different from that of 15.71 at King Sejong (62.2° S, 58.8° E) station. Acknowledgments The TIMED/SABER kinetic temperature (version 2.0) data are provided by the SABER team through http://saber.gats-inc.com/. The temperatures from the NRLMSISE-00 model are calculated using Aerospace Blockset toolbox of MATLAB (2016a). This research was supported by National Natural Science Foundation of China (41231065, 41321003). We acknowledge the use of meteor radar

  18. The determination of parameters of the upper atmosphere by the radio-meteor measurements

    Science.gov (United States)

    Shamukov, Damir; Fahrutdinova, Antonina; Nugmanov, Ildus

    Study of the parameters of the upper atmosphere on the basis of amplitude-time characteristics of meteor ionization. Together with various methods meteor observations (optical, photographic, visual, spectral, television), the most effective modern method of studying meteors means is radar. The development of modern radar technology allows us to apply this tool to monitor meteors. This method allows to determine the parameters of temperature and atmospheric pressure. Actual issue is the development of methods of determining the coefficient of ambipolar diffusion, pressure, density and temperature of the atmosphere in the meteor zone. Graph of amplitude-time characteristic has the exponential form. This fact allows to determine the coefficient of ambipolar diffusion. New algorithm for estimation of the ambipolar diffusion coefficient based on a set of statistical methods and techniques of digital signal processing. There are decomposition of data on singular values and Prony's method. This method of modeling the sample data as a linear combination of exponential. Prony’s method approximates the amplitude-time characteristics of using a deterministic exponential model. Input data is amplitude-time characteristics of the meteor trail x[1]…x[N]. The method allows to estimate x[n] p-membered exponential model: begin{center} x[n]=Sigma2A_{k}exp[a _{k}(n-1)]Cos[2Pif_{k}(n-1)T+Fi_{k}] (1) end{center} 1<=n<=N, T - time range in seconds, A_{k} and a_{k} - amplitude and damping coefficient, f_{k} and Fi_{k} - frequency and initial phase. The equation describing the decay of radio signal: begin{center} A=A_{0}exp(-16Pi^{2}$D_{a}t/λ (2) ). (2) lambdaλ - radar wavelength. The output of the algorithm - the ambipolar diffusion coefficient values D_{a}. begin{center} T=0.5lnD-T_{0}+mg/2kT_{0} (3) Last equation allows to obtain temperature values using the coefficient of ambipolar diffusion depends on the height.

  19. The Application of New Optical Meteor Flux Routines to the 2014 May Camelopardalid Outburst

    Science.gov (United States)

    Blaauw, Rhiannon; Campbell-Brown, Margaret; Kingery, Aaron

    2015-01-01

    NASA's Meteoroid Environment Office (MEO) is charged with monitoring the meteoroid environment in near-Earth space for the protection of satellites and spacecraft. The MEO has recently established eight wide-field meteor cameras, four cameras each at two separate stations to calculate automated meteor fluxes in the millimeter size range. Each camera consists of a 17 mm focal length Schneider lens on a Watec 902H2 Ultimate CCD video camera, producing a 21.7 x 15.5 degree field of view. This configuration has a limiting meteor magnitude of about +5. One station is located at Marshall Space Flight Center in Huntsville, Alabama and the other is 31.8 kilometers away at a school in Decatur, Alabama. Both single-station and double-station fluxes are calculated every morning using data from the previous night. The flux algorithms employed here differ from others currently in use in that they do not assume a single height for all meteors observed in the common camera volume. In the MEO system, the volume is broken up into a set of height intervals, with the collecting areas determined by the position of the active shower or sporadic source radiant. The flux per height interval is calculated and summed to obtain the total meteor flux. As the mass is also computed from the photometry, a mass flux can also be calculated. First, a weather algorithm indicates if sky conditions are clear enough to calculate fluxes, at which point a limiting magnitude algorithm is employed. The limiting magnitude algorithm performs a fit of stellar magnitudes versus camera intensities. The stellar limiting magnitude is derived from this and converted to a limiting meteor magnitude for the active shower or sporadic source. The fluxes are scaled to an average limiting magnitude throughout the night and zenithal hourly rate (ZHR's) are output daily along with flux values. In addition to this process, results will be presented as applied to the 2014 May Camelopardalid outburst, using data from several

  20. Lappajarvi Meteorite Crater, Western Finland: Structure, Stratigraphy and Geochemistry

    Science.gov (United States)

    Pipping, F.

    1992-07-01

    Research drill holes drilled in the 23 km diameter Lappajarvi Late Cretaceous meteorite impact crater give new information as to the structure, stratigraphy, and geochemistry of the impact formation in the crater (Pipping & Lehtinen, 1992). In one drill hole the sheet of glassy melt rock is 145 m thick and is underlain by 30 m of suevitic rock, followed by loose breccias down to 209 m where the hole ends. In a nearby hole 65 m of suevitic breccia was penetrated, underlain by a fine-grained allochthonous breccia to 160 m, followed by an autochthonous coarse breccia cut by suevitic dikes down to 275 m where the hole ends. A third hole was bored close to the crater rim. Topmost is 75 m of Quaternary glacial tills. After an erosional boundary follows 20 m of Mesoproterozoic (ca. 1200 Ma) sandy-silty sediments. These are underlain--with a tectonic boundary--by an autochthonous saprolite crust of about 40 m thickness. The hole ended in fresh mica schist--no signs of shock metamorphism--at 165 m. The structure typical for large impact craters was thus confirmed, i.e. an annular trough inside the rim of the crater, filled with rocks older than the impact. The stratigraphy of the crater fill is: lowermost autochthonous breccias followed by allochthonous breccias and suevitic breccias, with a melt rock cap covering a part of the crater fill. The general stratigraphy is: Palaeoproterozoic mica schists (1900 Ma), Mesoproterozoic saprolite (1400 Ma) in peneplanated schists, Neoproterozoic sediments (1200 Ma), Late Cretaceous crater (77 Ma, Jessberger & Reimold,1980) with a fill of impact rocks, Quaternary glaciation and sedimentation, and last, recent lake sedimentation. Impact rock geochemistry gives conclusive proof of an origin by meteorite impact. Conspicuous is the threefold Ni-content of the melt rock compared with the target rock, and the two-to-tenfold content of the Pt-metals in the melt rocks and suevites, compared with the target schists. Increased levels of K and Se