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Sample records for 20 100 kilometer kuiper

  1. MEASURING THE ABUNDANCE OF SUB-KILOMETER-SIZED KUIPER BELT OBJECTS USING STELLAR OCCULTATIONS

    SciTech Connect

    Schlichting, Hilke E.; Ofek, Eran O.; Gal-Yam, Avishay; Sari, Re'em; Nelan, Edmund P.; Livio, Mario; Wenz, Michael; Muirhead, Philip; Javanfar, Nikta

    2012-12-20

    We present here the analysis of about 19,500 new star hours of low ecliptic latitude observations (|b| {<=} 20 Degree-Sign ) obtained by the Hubble Space Telescope's Fine Guidance Sensors over a time span of more than nine years, which is in addition to the {approx}12, 000 star hours previously analyzed by Schlichting et al. Our search for stellar occultations by small Kuiper Belt Objects (KBOs) yielded one new candidate event corresponding to a body with a 530 {+-} 70 m radius at a distance of about 40 AU. Using bootstrap simulations, we estimate a probability of Almost-Equal-To 5% that this event is due to random statistical fluctuations within the new data set. Combining this new event with the single KBO occultation reported by Schlichting et al. we arrive at the following results: (1) the ecliptic latitudes of 6. Degree-Sign 6 and 14. Degree-Sign 4 of the two events are consistent with the observed inclination distribution of larger, 100-km-sized KBOs. (2) Assuming that small, sub-kilometer-sized KBOs have the same ecliptic latitude distribution as their larger counterparts, we find an ecliptic surface density of KBOs with radii larger than 250 m of N(r > 250 m) = 1.1{sup +1.5}{sub -0.7} Multiplication-Sign 10{sup 7} deg{sup -2}; if sub-kilometer-sized KBOs have instead a uniform ecliptic latitude distribution for -20 Degree-Sign < b < 20 Degree-Sign then N(r > 250 m) = 4.4{sup +5.8}{sub -2.8} Multiplication-Sign 10{sup 6} deg{sup -2}. This is the best measurement of the surface density of sub-kilometer-sized KBOs to date. (3) Assuming the KBO size distribution can be well described by a single power law given by N(> r){proportional_to}r{sup 1-q}, where N(> r) is the number of KBOs with radii greater than r, and q is the power-law index, we find q = 3.8 {+-} 0.2 and q = 3.6 {+-} 0.2 for a KBO ecliptic latitude distribution that follows the observed distribution for larger, 100-km-sized KBOs and a uniform KBO ecliptic latitude distribution for -20 Degree

  2. A 100-micron polarimeter for the Kuiper Airborne Observatory

    SciTech Connect

    Novak, G.; Gonatas, D.P.; Hildebrand, R.H.; Platt, S.R.

    1989-02-01

    Consideration is given to the design and performance of the 100-micron polarimeter proposed for use on the NASA Kuiper Airborne Observatory. The polarimeter specifications are listed. The polarimeter design and data reduction techniques are based on the work of Hildebrand et al. (1984) and Dragovan (1986). The polarimeter has an improved signal-to-noise ratio and systematic measurement errors below 0.2 percent. 20 refs.

  3. A 100-micron polarimeter for the Kuiper Airborne Observatory

    NASA Technical Reports Server (NTRS)

    Novak, G.; Gonatas, D. P.; Hildebrand, R. H.; Platt, S. R.

    1989-01-01

    Consideration is given to the design and performance of the 100-micron polarimeter proposed for use on the NASA Kuiper Airborne Observatory. The polarimeter specifications are listed. The polarimeter design and data reduction techniques are based on the work of Hildebrand et al. (1984) and Dragovan (1986). The polarimeter has an improved signal-to-noise ratio and systematic measurement errors below 0.2 percent.

  4. POINT COVERAGE OF AIRS MONITORING SITES WITHIN A 100 KILOMETER BUFFERUS/MEXICO BORDER

    EPA Science Inventory

    A point coverage of Aerometric Information Retrieval System (AIRS) within a 100 kilometer around the U.S./Mexico International Boundary. Airs is the national repository for information about airborne pollution in the United States.

  5. Structure of Mars' Atmosphere up to 100 Kilometers from the Entry Measurements of Viking 2.

    PubMed

    Seiff, A; Kirk, D B

    1976-12-11

    The Viking 2 entry science data on the structure of Mars' atmosphere up to 100 kilometers define a morning atmosphere with an isothermal region near the surface; a surface pressure 10 percent greater than that recorded simultaneously at the Viking 1 site, which implies a landing site elevation lower by 2.7 kilometers than the reference ellipsoid; and a thermal structure to 100 kilometers at least qualitatively consistent with pre-Viking modeling of thermal tides. The temperature profile exhibits waves whose amplitude grows with altitude, to approximately 25 degrees K at 90 kilometers. These waves are believed to be a consequence of layered vertical oscillations and associated heating and cooling by compression and expansion, excited by the daily thermal cycling of the planet surface. As is necessary for gravity wave propagation, the atmosphere is stable against convection, except possibly in some very local regions. Temperature is everywhere appreciably above the carbon dioxide condensation boundary at both landing sites, precluding the occurrence of carbon dioxide hazes in northern summer at latitudes to at least 50 degrees N. Thus, ground level mists seen in these latitudes would appear to be condensed water vapor. PMID:17797089

  6. 100-micron array polarimetry from the Kuiper Airborne Observatory - Instrumentation, techniques, and first results

    NASA Technical Reports Server (NTRS)

    Platt, S. R.; Hildebrand, R. H.; Pernic, R. J.; Davidson, J. A.; Novak, G.

    1991-01-01

    The University of Chicago far-infrared array polarimeter, 'STOKES', is the first multiple-beam polarimeter for far-infrared astronomy. Observations are made from the NASA Kuiper Airborne Observatory. Two orthogonal components of linear polarization are detected simultaneously by corresponding pairs of bolometers in two 32-detector arrays. Novel observing and data-analysis techniques are used to overcome the inherent difficulties of array polarimetry. Results from the first observing flights with the new instrument are reported for the molecular clouds W3 and W51. The measurements show that the magnetic-field structure in both clouds is nonuniform on the scale of 0.5-1.5 pc. This is consistent with molecular line and Zeeman observations that indicate the presence of turbulent velocities and significant small-scale structure. Preliminary results from the second flight series have yielded approximately 40 new measurements in the Sgr A complex. These results indicate that modifications made since the first flights have significantly improved the performance of STOKES.

  7. Collisional Evolution of Edgeworth-Kuiper Belt Objects

    NASA Astrophysics Data System (ADS)

    Davis, D. R.; Farinella, P.

    1997-01-01

    The Edgeworth-Kuiper Belt contains a population of objects ≈10 3times that of the main asteroid belt, spread over a volume ≈10 3larger and with relative speeds ≈10 times lower. As for the asteroids, the size distribution of Edgeworth-Kuiper Belt objects has been modified by mutual impacts over Solar System history. We have modeled this collisional evolution process using a numerical code developed originally to study asteroid collisional evolution but modified to reflect collision rates in the Edgeworth-Kuiper Belt. Our numerical simulations show that collisional evolution is substantial in the inner part of the Edgeworth-Kuiper Belt, but its intensity decreases with increasing distance from the Sun. In the inner belt, objects with diameters D> 50-100 km are not depleted by disruptive collisions; hence they reflect the original (formative) population (many of them, however, may have been converted into "rubble piles"). On the other hand, smaller objects are mostly multigenerational fragments, although the original population must have contained a significant number of bodies down to at least a few tens of kilometers in size in order to initiate a collisional cascade. About 10 fragments, 1-10 km in size, are produced per year in the inner Edgeworth-Kuiper Belt, with a few percent of them inserted into chaotic resonant orbits. This is in rough agreement with the required influx rate of Jupiter-family comets. Both collisions and dynamical instabilities associated with resonances are processes that can inject comets into the "escape hatches," but our results indicate that most comets coming from the Edgeworth-Kuiper Belt would be fragments from larger parent bodies, rather than primitive planetesimals. However, this does not apply to Chiron-sized ( D> 100 km) objects, which must be primordial and delivered to the outer Solar System by either dynamical processes or nondisruptive collisions.

  8. POINT COVERAGE OF 1990 US POPULATION DENSITY WITHIN A 100 KILOMETER BUFFER OF THE US/MEXICO BORDER

    EPA Science Inventory

    This is a point coverage of the 1990 Census of Population and Housing within a 100 kilo buffer around the US/Mexico Internation Boundary. The coverage contains the location of population points retrieved at the block group summary level and shows the total number of persons and ...

  9. 50 CFR 20.100 - General provisions.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... PLANTS (CONTINUED) MIGRATORY BIRD HUNTING Annual Seasons, Limits, and Shooting Hours Schedules § 20.100... schedules are established for seasons, daily bag and possession limits, and shooting (or hawking)...

  10. 50 CFR 20.100 - General provisions.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... PLANTS (CONTINUED) MIGRATORY BIRD HUNTING Annual Seasons, Limits, and Shooting Hours Schedules § 20.100... schedules are established for seasons, daily bag and possession limits, and shooting (or hawking)...

  11. Population of the Scattered Kuiper Belt.

    PubMed

    Trujillo; Jewitt; Luu

    2000-02-01

    We present the discovery of three new scattered Kuiper Belt objects (SKBOs) from a wide-field survey of the ecliptic. This continuing survey has to date covered 20.2 deg2 to a limiting red magnitude of 23.6. We combine the data from this new survey with an existing survey conducted at the University of Hawaii 2.2 m telescope to constrain the number and mass of the SKBOs. The SKBOs are characterized by large eccentricities, perihelia near 35 AU, and semimajor axes greater than 50 AU. Using a maximum likelihood model, we estimate the total number of SKBOs larger than 100 km in diameter to be N=&parl0;3.1+1.9-1.3&parr0;x104 (1 sigma errors) and the total mass of SKBOs to be M approximately 0.05 M plus sign in circle, demonstrating that the SKBOs are similar in number and mass to the Kuiper Belt inside 50 AU. PMID:10622765

  12. Beyond the Kuiper Belt Edge

    NASA Astrophysics Data System (ADS)

    Sheppard, Scott; Trujillo, Chad

    2012-02-01

    Of the thousands of known objects beyond Neptune, only one has a perihelion significantly beyond 50 AU, Sedna at 75 AU. Kuiper Belt surveys to date have not been optimized to survey beyond the Kuiper Belt edge at 50 AU. Most of these surveys either did not go faint enough, did not have the required long cadence to detect very slow moving objects or covered too small of an area of sky. The dynamical and physical properties of objects in this region offer key constraints on the formation and evolution of our solar system. In order to probe the Sedna like population of objects with moderate radii (100 km) we propose a medium wide-field outer solar system survey. This survey will allow us to determine if the objects beyond 50 AU are fainter than expected, if there is truly a dearth of objects, or if the Kuiper Belt continues again after some sizable gap possibly caused by a planet sized object. We will be able to examine the origin of Sedna and determine if this eccentric, distant body is unique (as once believed for Pluto) or just the first of a new class of object in the outer Solar System.

  13. Beyond the Kuiper Belt Edge

    NASA Astrophysics Data System (ADS)

    Sheppard, Scott

    2012-06-01

    Of the thousands of known objects beyond Neptune, only one has a perihelion significantly beyond 50 AU, Sedna at 75 AU. Kuiper Belt surveys to date have not been optimized to survey beyond the Kuiper Belt edge at 50 AU. Most of these surveys either did not go faint enough, did not have the required long cadence to detect very slow moving objects or covered too small of an area of sky. The dynamical and physical properties of objects in this region offer key constraints on the formation and evolution of our solar system. In order to probe the Sedna like population of objects with moderate radii (100 km) we propose a deep wide-field outer solar system survey. This survey will allow us to determine if the objects beyond 50 AU are fainter than expected, if there is truly a dearth of objects, or if the Kuiper Belt continues again after some sizable gap possibly caused by a planet sized object. We will be able to examine the origin of Sedna and determine if this eccentric, distant body is unique (as once believed for Pluto) or just the first of a new class of object in the outer Solar System. We will also explore the Neptune Trojans and scattered disk populations through the survey.

  14. A POSSIBLE DIVOT IN THE SIZE DISTRIBUTION OF THE KUIPER BELT'S SCATTERING OBJECTS

    SciTech Connect

    Shankman, C.; Gladman, B. J.; Kaib, N.; Kavelaars, J. J.; Petit, J. M.

    2013-02-10

    Via joint analysis of a calibrated telescopic survey, which found scattering Kuiper Belt objects, and models of their expected orbital distribution, we explore the scattering-object (SO) size distribution. Although for D > 100 km the number of objects quickly rise as diameters decrease, we find a relative lack of smaller objects, ruling out a single power law at greater than 99% confidence. After studying traditional ''knees'' in the size distribution, we explore other formulations and find that, surprisingly, our analysis is consistent with a very sudden decrease (a divot) in the number distribution as diameters decrease below 100 km, which then rises again as a power law. Motivated by other dynamically hot populations and the Centaurs, we argue for a divot size distribution where the number of smaller objects rises again as expected via collisional equilibrium. Extrapolation yields enough kilometer-scale SOs to supply the nearby Jupiter-family comets. Our interpretation is that this divot feature is a preserved relic of the size distribution made by planetesimal formation, now ''frozen in'' to portions of the Kuiper Belt sharing a ''hot'' orbital inclination distribution, explaining several puzzles in Kuiper Belt science. Additionally, we show that to match today's SO inclination distribution, the supply source that was scattered outward must have already been vertically heated to the of order 10 Degree-Sign .

  15. A Possible Divot in the Size Distribution of the Kuiper Belt's Scattering Objects

    NASA Astrophysics Data System (ADS)

    Shankman, C.; Gladman, B. J.; Kaib, N.; Kavelaars, J. J.; Petit, J. M.

    2013-02-01

    Via joint analysis of a calibrated telescopic survey, which found scattering Kuiper Belt objects, and models of their expected orbital distribution, we explore the scattering-object (SO) size distribution. Although for D > 100 km the number of objects quickly rise as diameters decrease, we find a relative lack of smaller objects, ruling out a single power law at greater than 99% confidence. After studying traditional "knees" in the size distribution, we explore other formulations and find that, surprisingly, our analysis is consistent with a very sudden decrease (a divot) in the number distribution as diameters decrease below 100 km, which then rises again as a power law. Motivated by other dynamically hot populations and the Centaurs, we argue for a divot size distribution where the number of smaller objects rises again as expected via collisional equilibrium. Extrapolation yields enough kilometer-scale SOs to supply the nearby Jupiter-family comets. Our interpretation is that this divot feature is a preserved relic of the size distribution made by planetesimal formation, now "frozen in" to portions of the Kuiper Belt sharing a "hot" orbital inclination distribution, explaining several puzzles in Kuiper Belt science. Additionally, we show that to match today's SO inclination distribution, the supply source that was scattered outward must have already been vertically heated to the of order 10°.

  16. 49 CFR 179.100-20 - Stamping.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... follows: Example of required stamping Specification DOT-105A100W Material ASTM A 516 Cladding material (if any) ASTM A240-304 Tank builder's initials Clad Date of original test ABC Car assembler (if other...

  17. 49 CFR 179.100-20 - Stamping.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... outside heads as follows: Example of required stamping Specification DOT-105A100W Material ASTM A 516 Cladding material (if any) ASTM A240-304 Tank builder's initials Clad Date of original test ABC...

  18. Beyond the Kuiper Belt Edge

    NASA Astrophysics Data System (ADS)

    Sheppard, Scott

    2012-01-01

    Of the thousands of known objects beyond Neptune, only one has a perihelion significantly beyond 50 AU, Sedna at 75 AU. Most Kuiper Belt surveys to date either did not go faint enough, did not have the required long cadence to detect very slow moving objects or covered too small of an area of sky to efficiently detect objects beyond 50 AU. The dynamical and physical properties of objects in this region offer key constraints on the formation and evolution of our solar system. In order to probe the Sedna like population of objects with moderate radii (100 km) we are conducting a deep wide-field outer solar system survey. This survey will allow us to determine if the objects beyond 50 AU are fainter than expected, if there is truly a dearth of objects, or if the Kuiper Belt continues again after some sizable gap possibly caused by a planet sized object. We will be able to examine the origin of Sedna and determine if it is unique (as once believed for Pluto) or one of a new class of object. We request one night in 2012B to recover interesting objects that will be discovered at Subaru in July 2012 and complete the sky coverage needed to constrain the Sedna-like population.

  19. Beyond the Kuiper Belt Edge

    NASA Astrophysics Data System (ADS)

    Sheppard, Scott

    2013-01-01

    Of the thousands of known objects beyond Neptune, only one has a perihelion significantly beyond 50 AU, Sedna at 75 AU. Most Kuiper Belt surveys to date either did not go faint enough, did not have the required long cadence to detect very slow moving objects or covered too small of an area of sky to efficiently detect objects beyond 50 AU. The dynamical and physical properties of objects in this region offer key constraints on the formation and evolution of our solar system. In order to probe the Sedna like population of objects with moderate radii (100 km) we are conducting a deep wide-field outer solar system survey. This survey will allow us to determine if the objects beyond 50 AU are fainter than expected, if there is truly a dearth of objects, or if the Kuiper Belt continues again after some sizable gap possibly caused by a planet sized object. We will be able to examine the origin of Sedna and determine if it is unique (as once believed for Pluto) or one of a new class of object. We request one night in 2013B to recover a very interesting object that we discovered at Subaru in July 2012 and complete the sky coverage needed to constrain the Sedna-like population. This one night was awarded to us in 2012B but lost because of instrument problems.

  20. 20 CFR 411.100 - Scope.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...' Benefits SOCIAL SECURITY ADMINISTRATION THE TICKET TO WORK AND SELF-SUFFICIENCY PROGRAM Introduction § 411.100 Scope. The regulations in this part 411 relate to the provisions of section 1148 of the Social... H contains provisions establishing employment network payment systems. (i) Subpart I...

  1. 20 CFR 411.100 - Scope.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...' Benefits SOCIAL SECURITY ADMINISTRATION THE TICKET TO WORK AND SELF-SUFFICIENCY PROGRAM Introduction § 411.100 Scope. The regulations in this part 411 relate to the provisions of section 1148 of the Social... H contains provisions establishing employment network payment systems. (i) Subpart I...

  2. 20 CFR 411.100 - Scope.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...' Benefits SOCIAL SECURITY ADMINISTRATION THE TICKET TO WORK AND SELF-SUFFICIENCY PROGRAM Introduction § 411.100 Scope. The regulations in this part 411 relate to the provisions of section 1148 of the Social... H contains provisions establishing employment network payment systems. (i) Subpart I...

  3. 20 CFR 411.100 - Scope.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...' Benefits SOCIAL SECURITY ADMINISTRATION THE TICKET TO WORK AND SELF-SUFFICIENCY PROGRAM Introduction § 411.100 Scope. The regulations in this part 411 relate to the provisions of section 1148 of the Social... H contains provisions establishing employment network payment systems. (i) Subpart I...

  4. 20 CFR 411.100 - Scope.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...' Benefits SOCIAL SECURITY ADMINISTRATION THE TICKET TO WORK AND SELF-SUFFICIENCY PROGRAM Introduction § 411.100 Scope. The regulations in this part 411 relate to the provisions of section 1148 of the Social... H contains provisions establishing employment network payment systems. (i) Subpart I...

  5. 31 CFR 20.100 - What does this part do?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 31 Money and Finance: Treasury 1 2011-07-01 2011-07-01 false What does this part do? 20.100 Section 20.100 Money and Finance: Treasury Office of the Secretary of the Treasury GOVERNMENTWIDE REQUIREMENTS FOR DRUG-FREE WORKPLACE (FINANCIAL ASSISTANCE) Purpose and Coverage § 20.100 What does this...

  6. 31 CFR 20.100 - What does this part do?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 31 Money and Finance: Treasury 1 2010-07-01 2010-07-01 false What does this part do? 20.100 Section 20.100 Money and Finance: Treasury Office of the Secretary of the Treasury GOVERNMENTWIDE REQUIREMENTS FOR DRUG-FREE WORKPLACE (FINANCIAL ASSISTANCE) Purpose and Coverage § 20.100 What does this...

  7. Kuiper Belt Mapping Radar

    NASA Technical Reports Server (NTRS)

    Freeman, A.; Nilsen, E.

    2001-01-01

    Since their initial discovery in 1992, to date only a relatively small number of Kuiper Belt Objects (KBO's) have been discovered. Current detection techniques rely on frame-to-frame comparisons of images collected by optical telescopes such as Hubble, to detect KBO's as they move against the background stellar field. Another technique involving studies of KBO's through occultation of known stars has been proposed. Such techniques are serendipitous, not systematic, and may lead to an inadequate understanding of the size, range, and distribution of KBO's. In this paper, a future Kuiper Belt Mapping Radar is proposed as a solution to the problem of mapping the size distribution, extent, and range of KBO's. This approach can also be used to recover radar albedo and object rotation rates. Additional information is contained in the original extended abstract.

  8. Infrared Kuiper Belt Constraints

    SciTech Connect

    Teplitz, V.L.; Stern, S.A.; Anderson, J.D.; Rosenbaum, D.; Scalise, R.J.; Wentzler, P.

    1999-05-01

    We compute the temperature and IR signal of particles of radius {ital a} and albedo {alpha} at heliocentric distance {ital R}, taking into account the emissivity effect, and give an interpolating formula for the result. We compare with analyses of {ital COBE} DIRBE data by others (including recent detection of the cosmic IR background) for various values of heliocentric distance {ital R}, particle radius {ital a}, and particle albedo {alpha}. We then apply these results to a recently developed picture of the Kuiper belt as a two-sector disk with a nearby, low-density sector (40{lt}R{lt}50{endash}90 AU) and a more distant sector with a higher density. We consider the case in which passage through a molecular cloud essentially cleans the solar system of dust. We apply a simple model of dust production by comet collisions and removal by the Poynting-Robertson effect to find limits on total and dust masses in the near and far sectors as a function of time since such a passage. Finally, we compare Kuiper belt IR spectra for various parameter values. Results of this work include: (1) numerical limits on Kuiper belt dust as a function of ({ital R}, {ital a}, {alpha}) on the basis of four alternative sets of constraints, including those following from recent discovery of the cosmic IR background by Hauser et al.; (2) application to the two-sector Kuiper belt model, finding mass limits and spectrum shape for different values of relevant parameters including dependence on time elapsed since last passage through a molecular cloud cleared the outer solar system of dust; and (3) potential use of spectral information to determine time since last passage of the Sun through a giant molecular cloud. {copyright} {ital {copyright} 1999.} {ital The American Astronomical Society}

  9. Prevalence and Genetic Diversity of Campylobacter spp. in Environmental Water Samples from a 100-Square-Kilometer Predominantly Dairy Farming Area

    PubMed Central

    Kemp, R.; Leatherbarrow, A. J. H.; Williams, N. J.; Hart, C. A.; Clough, H. E.; Turner, J.; Wright, E. J.; French, N. P.

    2005-01-01

    Water samples were taken systematically from a 100-km2 area of mainly dairy farmland in northwestern England and examined for Campylobacter spp. Pulsed-field gel electrophoresis-restriction fragment length polymorphism (PFGE-RFLP) and flaA strain typing of Campylobacter jejuni and Campylobacter coli isolates were done. Data on the water source and the adjacent environment were recorded and examined as explanatory variables. Campylobacter spp. were isolated from 40.5% (n = 119) of the water samples tested. C. jejuni was isolated from 14.3%, C. coli was isolated from 18.5%, and Campylobacter lari was isolated from 4.2% of the samples. Campylobacter hyointestinalis was not isolated from any water source. The difference in prevalence between water types (trough, running, and standing) was significant (P = 0.001). C. jejuni was the species most commonly isolated from trough-water and running-water sources, while C. coli was the most frequently isolated from standing water (P < 0.001). No association was found between the presence of Escherichia coli and that of Campylobacter spp. The final multivariable logistic regression model for Campylobacter spp. included the following variables: water source, soil type, aspect, and amount of cattle fecal material in the environment (fecal pat count). Strain typing demonstrated a diverse population of C. jejuni and the presence of a common C. coli flaA type that was widely distributed throughout the area. Most of the isolates within the common flaA type were discriminated by PFGE-RFLP. These findings suggest a possible role for environmental water in the epidemiology of Campylobacter spp. in a farming environment. PMID:15812015

  10. 20 CFR 664.100 - What is the youth council?

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... section 117(h) and 20 CFR 661.335 and 661.340. (b) The purpose of the youth council is to provide... 20 Employees' Benefits 4 2012-04-01 2012-04-01 false What is the youth council? 664.100 Section...) YOUTH ACTIVITIES UNDER TITLE I OF THE WORKFORCE INVESTMENT ACT Youth Councils § 664.100 What is...

  11. 20 CFR 664.100 - What is the youth council?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...) and 20 CFR 661.335 and 661.340. (b) The purpose of the youth council is to provide expertise in youth... 20 Employees' Benefits 3 2011-04-01 2011-04-01 false What is the youth council? 664.100 Section 664.100 Employees' Benefits EMPLOYMENT AND TRAINING ADMINISTRATION, DEPARTMENT OF LABOR...

  12. 20 CFR 664.100 - What is the youth council?

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... section 117(h) and 20 CFR 661.335 and 661.340. (b) The purpose of the youth council is to provide... 20 Employees' Benefits 4 2013-04-01 2013-04-01 false What is the youth council? 664.100 Section...) YOUTH ACTIVITIES UNDER TITLE I OF THE WORKFORCE INVESTMENT ACT Youth Councils § 664.100 What is...

  13. 20 CFR 664.100 - What is the youth council?

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... section 117(h) and 20 CFR 661.335 and 661.340. (b) The purpose of the youth council is to provide... 20 Employees' Benefits 4 2014-04-01 2014-04-01 false What is the youth council? 664.100 Section...) YOUTH ACTIVITIES UNDER TITLE I OF THE WORKFORCE INVESTMENT ACT Youth Councils § 664.100 What is...

  14. 20 CFR 645.100 - What does this part cover?

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... found at 20 CFR part 646. ... 20 Employees' Benefits 3 2012-04-01 2012-04-01 false What does this part cover? 645.100 Section... GOVERNING WELFARE-TO-WORK GRANTS Scope and Purpose § 645.100 What does this part cover? (a) Subpart...

  15. 20 CFR 498.100 - Basis and purpose.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 20 Employees' Benefits 2 2011-04-01 2011-04-01 false Basis and purpose. 498.100 Section 498.100 Employees' Benefits SOCIAL SECURITY ADMINISTRATION CIVIL MONETARY PENALTIES, ASSESSMENTS AND RECOMMENDED EXCLUSIONS § 498.100 Basis and purpose. (a) Basis. This part implements sections 1129 and 1140 of the...

  16. 20 CFR 498.100 - Basis and purpose.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 20 Employees' Benefits 2 2013-04-01 2013-04-01 false Basis and purpose. 498.100 Section 498.100 Employees' Benefits SOCIAL SECURITY ADMINISTRATION CIVIL MONETARY PENALTIES, ASSESSMENTS AND RECOMMENDED EXCLUSIONS § 498.100 Basis and purpose. (a) Basis. This part implements sections 1129 and 1140 of the...

  17. 20 CFR 498.100 - Basis and purpose.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 20 Employees' Benefits 2 2012-04-01 2012-04-01 false Basis and purpose. 498.100 Section 498.100 Employees' Benefits SOCIAL SECURITY ADMINISTRATION CIVIL MONETARY PENALTIES, ASSESSMENTS AND RECOMMENDED EXCLUSIONS § 498.100 Basis and purpose. (a) Basis. This part implements sections 1129 and 1140 of the...

  18. 20 CFR 498.100 - Basis and purpose.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 2 2010-04-01 2010-04-01 false Basis and purpose. 498.100 Section 498.100 Employees' Benefits SOCIAL SECURITY ADMINISTRATION CIVIL MONETARY PENALTIES, ASSESSMENTS AND RECOMMENDED EXCLUSIONS § 498.100 Basis and purpose. (a) Basis. This part implements sections 1129 and 1140 of the...

  19. 20 CFR 498.100 - Basis and purpose.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 20 Employees' Benefits 2 2014-04-01 2014-04-01 false Basis and purpose. 498.100 Section 498.100 Employees' Benefits SOCIAL SECURITY ADMINISTRATION CIVIL MONETARY PENALTIES, ASSESSMENTS AND RECOMMENDED EXCLUSIONS § 498.100 Basis and purpose. (a) Basis. This part implements sections 1129 and 1140 of the...

  20. 20 CFR 641.100 - What does this part cover?

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 20 Employees' Benefits 3 2012-04-01 2012-04-01 false What does this part cover? 641.100 Section 641.100 Employees' Benefits EMPLOYMENT AND TRAINING ADMINISTRATION, DEPARTMENT OF LABOR PROVISIONS GOVERNING THE SENIOR COMMUNITY SERVICE EMPLOYMENT PROGRAM Purpose and Definitions § 641.100 What does...

  1. 20. Historic south and west elevation drawing of Building 100. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    20. Historic south and west elevation drawing of Building 100. June 29, 1955. NASA GRC drawing number CE-101443. (On file at NASA Glenn Research Center). - Rocket Engine Testing Facility, GRC Building No. 100, NASA Glenn Research Center, Cleveland, Cuyahoga County, OH

  2. 20 CFR 652.100 - Services for veterans.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 20 Employees' Benefits 3 2012-04-01 2012-04-01 false Services for veterans. 652.100 Section 652... FUNCTIONING OF STATE EMPLOYMENT SERVICES Services for Veterans § 652.100 Services for veterans. Services for veterans are administered by the Office of the Assistant Secretary for Veterans' Employment and...

  3. 20 CFR 652.100 - Services for veterans.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 20 Employees' Benefits 3 2014-04-01 2014-04-01 false Services for veterans. 652.100 Section 652... FUNCTIONING OF STATE EMPLOYMENT SERVICES Services for Veterans § 652.100 Services for veterans. Services for veterans are administered by the Office of the Assistant Secretary for Veterans' Employment and...

  4. 20 CFR 652.100 - Services for veterans.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 20 Employees' Benefits 3 2013-04-01 2013-04-01 false Services for veterans. 652.100 Section 652... FUNCTIONING OF STATE EMPLOYMENT SERVICES Services for Veterans § 652.100 Services for veterans. Services for veterans are administered by the Office of the Assistant Secretary for Veterans' Employment and...

  5. 20 CFR 652.100 - Services for veterans.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false Services for veterans. 652.100 Section 652... FUNCTIONING OF STATE EMPLOYMENT SERVICES Services for Veterans § 652.100 Services for veterans. Services for veterans are administered by the Office of the Assistant Secretary for Veterans' Employment and...

  6. 20 CFR 652.100 - Services for veterans.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 20 Employees' Benefits 3 2011-04-01 2011-04-01 false Services for veterans. 652.100 Section 652... FUNCTIONING OF STATE EMPLOYMENT SERVICES Services for Veterans § 652.100 Services for veterans. Services for veterans are administered by the Office of the Assistant Secretary for Veterans' Employment and...

  7. 20 CFR 672.100 - What is YouthBuild?

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 20 Employees' Benefits 4 2013-04-01 2013-04-01 false What is YouthBuild? 672.100 Section 672.100... GOVERNING THE YOUTHBUILD PROGRAM Purpose and Definitions § 672.100 What is YouthBuild? (a) YouthBuild is a... opportunities to disadvantaged and low-income youth between the ages of 16 and 24, most of whom are...

  8. 20 CFR 672.100 - What is YouthBuild?

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 20 Employees' Benefits 4 2014-04-01 2014-04-01 false What is YouthBuild? 672.100 Section 672.100... GOVERNING THE YOUTHBUILD PROGRAM Purpose and Definitions § 672.100 What is YouthBuild? (a) YouthBuild is a... opportunities to disadvantaged and low-income youth between the ages of 16 and 24, most of whom are...

  9. 20 CFR 672.100 - What is YouthBuild?

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 20 Employees' Benefits 4 2012-04-01 2012-04-01 false What is YouthBuild? 672.100 Section 672.100... GOVERNING THE YOUTHBUILD PROGRAM Purpose and Definitions § 672.100 What is YouthBuild? (a) YouthBuild is a... opportunities to disadvantaged and low-income youth between the ages of 16 and 24, most of whom are...

  10. The extreme Kuiper Belt binary 2001 QW322.

    PubMed

    Petit, J-M; Kavelaars, J J; Gladman, B J; Margot, J L; Nicholson, P D; Jones, R L; Parker, J Wm; Ashby, M L N; Bagatin, A Campo; Benavidez, P; Coffey, J; Rousselot, P; Mousis, O; Taylor, P A

    2008-10-17

    The study of binary Kuiper Belt objects helps to probe the dynamic conditions present during planet formation in the solar system. We report on the mutual-orbit determination of 2001 QW322, a Kuiper Belt binary with a very large separation whose properties challenge binary-formation and -evolution theories. Six years of tracking indicate that the binary's mutual-orbit period is approximately 25 to 30 years, that the orbit pole is retrograde and inclined 50 degrees to 62 degrees from the ecliptic plane, and, most surprisingly, that the mutual orbital eccentricity is <0.4. The semimajor axis of 105,000 to 135,000 kilometers is 10 times that of other near-equal-mass binaries. Because this weakly bound binary is prone to orbital disruption by interlopers, its lifetime in its present state is probably less than 1 billion years. PMID:18927391

  11. Euclid Asteroseismology and Kuiper Belt Objects

    NASA Astrophysics Data System (ADS)

    Gould, Andrew; Huber, Daniel; Stello, Dennis

    2016-02-01

    Euclid, which is primarily a dark-energy/cosmology mission, may have a microlensing component, consisting of perhaps four dedicated one-month campaigns aimed at the Galactic bulge. We show that such a program would yield excellent auxilliary science, including asteroseismology detections for about 100,000 giant stars, and detection of about 1000 Kuiper Belt Objects (KBOs), down to 2--2.5 mag below the observed break in the KBO luminosity function at I˜ 26. For the 400 KBOs below the break, Euclid will measure accurate orbits, with fractional period errors ≲ 2.5%.

  12. 31 CFR 20.100 - What does this part do?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... REQUIREMENTS FOR DRUG-FREE WORKPLACE (FINANCIAL ASSISTANCE) Purpose and Coverage § 20.100 What does this part do? This part carries out the portion of the Drug-Free Workplace Act of 1988 (41 U.S.C. 701 et seq... agreements and other financial assistance awards, as a matter of Federal Government policy....

  13. 31 CFR 20.100 - What does this part do?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... REQUIREMENTS FOR DRUG-FREE WORKPLACE (FINANCIAL ASSISTANCE) Purpose and Coverage § 20.100 What does this part do? This part carries out the portion of the Drug-Free Workplace Act of 1988 (41 U.S.C. 701 et seq... agreements and other financial assistance awards, as a matter of Federal Government policy....

  14. 31 CFR 20.100 - What does this part do?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... REQUIREMENTS FOR DRUG-FREE WORKPLACE (FINANCIAL ASSISTANCE) Purpose and Coverage § 20.100 What does this part do? This part carries out the portion of the Drug-Free Workplace Act of 1988 (41 U.S.C. 701 et seq... agreements and other financial assistance awards, as a matter of Federal Government policy....

  15. WATER ICE IN THE KUIPER BELT

    SciTech Connect

    Brown, M. E.; Fraser, W. C.; Schaller, E. L.

    2012-06-15

    We examine a large collection of low-resolution near-infrared spectra of Kuiper Belt objects (KBOs) and centaurs in an attempt to understand the presence of water ice in the Kuiper Belt. We find that water ice on the surface of these objects occurs in three separate manners: (1) Haumea family members uniquely show surfaces of nearly pure water ice, presumably a consequence of the fragmentation of the icy mantle of a larger differentiated proto-Haumea; (2) large objects with absolute magnitudes of H < 3 (and a limited number to H = 4.5) have surface coverings of water ice-perhaps mixed with ammonia-that appears to be related to possibly ancient cryovolcanism on these large objects; and (3) smaller KBOs and centaurs which are neither Haumea family members nor cold-classical KBOs appear to divide into two families (which we refer to as 'neutral' and 'red'), each of which is a mixture of a common nearly neutral component and either a slightly red or very red component that also includes water ice. A model suggesting that the difference between neutral and red objects due to formation in an early compact solar system either inside or outside, respectively, of the {approx}20 AU methanol evaporation line is supported by the observation that methanol is only detected on the reddest objects, which are those which would be expected to have the most of the methanol containing mixture.

  16. The Scattered Kuiper Belt Objects

    NASA Astrophysics Data System (ADS)

    Trujillo, C. A.; Jewitt, D. C.; Luu, J. X.

    1999-09-01

    We describe a continuing survey of the Kuiper Belt conducted at the 3.6-m Canada France Hawaii Telescope on Mauna Kea, Hawaii. The survey employs a 12288 x 8192 pixel CCD mosaic to image the sky to red magnitude 24. All detected objects are targeted for systematic follow-up observations, allowing us to determine their orbital characteristics. Three new members of the rare Scattered Kuiper Belt Object class have been identified, bringing the known population of such objects to four. The SKBOs are thought to have been scattered outward by Neptune, and are a potential source of the short-period comets. Using a Maximum Likelihood method, we place observational constraints on the total number and mass of the SKBOs.

  17. The binary Kuiper-belt object 1998 WW31.

    PubMed

    Veillet, Christian; Parker, Joel Wm; Griffin, Ian; Marsden, Brian; Doressoundiram, Alain; Buie, Marc; Tholen, David J; Connelley, Michael; Holman, Matthew J

    2002-04-18

    The recent discovery of a binary asteroid during a spacecraft fly-by generated keen interest, because the orbital parameters of binaries can provide measures of the masses, and mutual eclipses could allow us to determine individual sizes and bulk densities. Several binary near-Earth, main-belt and Trojan asteroids have subsequently been discovered. The Kuiper belt-the region of space extending from Neptune (at 30 astronomical units) to well over 100 AU and believed to be the source of new short-period comets-has become a fascinating new window onto the formation of our Solar System since the first member object, not counting Pluto, was discovered in 1992 (ref. 13). Here we report that the Kuiper-belt object 1998 WW31 is binary with a highly eccentric orbit (eccentricity e approximately 0.8) and a long period (about 570 days), very different from the Pluto/Charon system, which was hitherto the only previously known binary in the Kuiper belt. Assuming a density in the range of 1 to 2 g cm-3, the albedo of the binary components is between 0.05 and 0.08, close to the value of 0.04 generally assumed for Kuiper-belt objects. PMID:11961547

  18. Distribution of Dust from Kuiper Belt Objects

    NASA Technical Reports Server (NTRS)

    Gorkavyi, Nick N.; Ozernoy, Leonid; Taidakova, Tanya; Mather, John C.; Fisher, Richard (Technical Monitor)

    2000-01-01

    Using an efficient computational approach, we have reconstructed the structure of the dust cloud in the Solar system between 0.5 and 100 AU produced by the Kuiper belt objects. Our simulations offer a 3-D physical model of the 'kuiperoidal' dust cloud based on the distribution of 280 dust particle trajectories produced by 100 known Kuiper belt objects; the resulting 3-D grid consists of 1.9 x 10' cells containing 1.2 x 10" particle positions. The following processes that influence the dust particle dynamics are taken into account: 1) gravitational scattering on the eight planets (neglecting Pluto); 2) planetary resonances; 3) radiation pressure; and 4) the Poynting-Robertson (P-R) and solar wind drags. We find the dust distribution highly non-uniform: there is a minimum in the kuiperoidal dust between Mars and Jupiter, after which both the column and number densities of kuiperoidal dust sharply increase with heliocentric distance between 5 and 10 AU, and then form a plateau between 10 and 50 AU. Between 25 and 45 AU, there is an appreciable concentration of kuiperoidal dust in the form of a broad belt of mostly resonant particles associated with Neptune. In fact, each giant planet possesses its own circumsolar dust belt consisting of both resonant and gravitationally scattered particles. As with the cometary belts simulated in our related papers, we reveal a rich and sophisticated resonant structure of the dust belts containing families of resonant peaks and gaps. An important result is that both the column and number dust density are more or less flat between 10 and 50 AU, which might explain the surprising data obtained by Pioneers 10 & 11 and Voyager that the dust number density remains approximately distance-independent in this region. The simulated kuiperoidal dust, in addition to asteroidal and cometary dust, might represent a third possible source of the zodiacal light in the Solar system.

  19. Exploration of the Kuiper Belt by serendipitous occultations using Ultraphot and MeFos instruments

    NASA Astrophysics Data System (ADS)

    Roques, F.; Guinouard, I.; Doressoundiram, A.; Felenbok, P.; Boissel, Y.; Sicardy, B.

    2008-09-01

    operated on VLT/UT2, and would have access to the entire field of the Nasmyth focus (25' diameter). The number of fibers of UltraPhot will be determined as a compromise between the camera read-out frequency and the capacity of the positioning system. Our estimates are based on a total of 100 to 200 fibers for a read-out frequency of 100 Hz using a 2 color photometry mode. The expected S/N ratio could be at least 10 3 /√f, where f is the read-out frequency for a magnitude 13. Potential interested scientific fields are numerous : Exploration of Outer Solar System Objects by stellar occultations : The aim is to characterize the small end of size distribution and the outer part of the Solar System population by a collection of serendipitous events. A challenge is the possibility to explore the Oort Cloud (using this method, we estimate a 5-kilometer comet-like object can be positively detected at a distance of 10000 AU). Extrasolar Planets Transits : Ultraphot will allow follow up of the Corot/Kepler targets. High precision photometry associated with a large field of view (1/20 of the Corot Exoplanets FOV) makes Ultraphot a powerful tool to explore the transit exoplanetary systems and to detect small planets. Moreover, precise timing of transits give access to other planets in the system by their perturbations on the orbits parameters. Study of variable objects in Globular Clusters (GC) would also benefit from this instrument. Searching for rapid periodic variations of blue objects might help to identify their nature. In particular Compact Binaries (CB) including Cataclysmic Variables are predicted to be numerous in GC not only in the cores but also in their outskirts. References [1] Roques, F. et Moncuquet M. (2000) A Detection Method for the Small Kuiper Belt Objects: The Stellar Occultations. Icarus, 147, 530-544. [2] F. Roques , A. Doressoundiram et al. (2006) Small and Distant Kuiper Belt Objects revealed by Stellar occultations, AJ, 132, 819 [3] Georgevits G. (2006

  20. THE COLLISIONAL DIVOT IN THE KUIPER BELT SIZE DISTRIBUTION

    SciTech Connect

    Fraser, Wesley C.

    2009-11-20

    This paper presents the results of collisional evolution calculations for the Kuiper Belt starting from an initial size distribution similar to that produced by accretion simulations of that region-a steep power-law large object size distribution that breaks to a shallower slope at r approx 1-2 km, with collisional equilibrium achieved for objects r approx< 0.5 km. We find that the break from the steep large object power law causes a divot, or depletion of objects at r approx 10-20 km, which, in turn, greatly reduces the disruption rate of objects with r approx> 25-50 km, preserving the steep power-law behavior for objects at this size. Our calculations demonstrate that the roll-over observed in the Kuiper Belt size distribution is naturally explained as an edge of a divot in the size distribution; the radius at which the size distribution transitions away from the power law, and the shape of the divot from our simulations are consistent with the size of the observed roll-over, and size distribution for smaller bodies. Both the kink radius and the radius of the divot center depend on the strength scaling law in the gravity regime for Kuiper Belt objects. These simulations suggest that the sky density of r approx 1 km objects is approx10{sup 6}-10{sup 7} objects per square degree. A detection of the divot in the size distribution would provide a measure of the strength of large Kuiper Belt objects, and constrain the shape of the size distribution at the end of accretion in the Kuiper Belt.

  1. Photographer : JPL Range : 225,000 kilometers (140,625 miles) This image of the Jovian moon Europa

    NASA Technical Reports Server (NTRS)

    1979-01-01

    Photographer : JPL Range : 225,000 kilometers (140,625 miles) This image of the Jovian moon Europa was taken by Voyager 2 along the evening terminator, which best shows the surface topography of complex narrow ridges, seen as curved bright streaks, 5 to 10 kilometers wide, and typically 100 kilometers in length. The area shown is about 600 by 800 kilometers, and the smallest features visible are about 4 kilometers in size. Also visable are dark bands, more diffused in character, 20 to 40 kilometers wide and hundreds to thousands of kilometers in length. A few features are suggestive of impact craters but are rare, indication that the surface thought to be dominantly ice is still active, perhaps warmed by tidal heating like Io. The larger icy satellites, Callisto and Ganymede, are evidently colder with much more rigid crusts and ancient impact craters. The complex intersection of dark markings and bright ridges suggest that the surface has been fractured and material from beneath has welled up to fill the cracks.

  2. 20 CFR 653.100 - Purpose and scope of subpart.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... THE EMPLOYMENT SERVICE SYSTEM Services for Migrant and Seasonal Farmworkers (MSFWs) § 653.100 Purpose... seasonal farmworkers (MSFWs) on a basis which is qualitatively equivalent and quantitatively...

  3. 20 CFR 653.100 - Purpose and scope of subpart.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... THE EMPLOYMENT SERVICE SYSTEM Services for Migrant and Seasonal Farmworkers (MSFWs) § 653.100 Purpose... seasonal farmworkers (MSFWs) on a basis which is qualitatively equivalent and quantitatively...

  4. Gerard Kuiper and the Infrared Detector

    NASA Astrophysics Data System (ADS)

    Sears, Derek

    2013-10-01

    The life and contributions of Gerard Kuiper have been documented by Dale Cruikshank in his National Academy of Sciences biography. I will argue that particularly important in this eventful life was Kuiper's war time experiences. Kuiper's wartime role evolved as the war unfolded, but towards the end he was charged by the US military with reporting German progress with war-related technologies and the activities of scientists under Nazi control. He interviewed a great many scientists, including his own PhD mentor (Ejnar Hertzsprung), and when Kuiper was the only person available, he interviewed concentration-camp victims. He carried briefing sheets that identified the technologies being sought by the allies and the major fraction of these involved infrared equipment. He sent back to the USA boxes of documents, and large amounts of equipment, and he stressed to the military his interest in these for his own research. It seems very likely that in this way an effective PbS infrared detector, so critical to Kuiper's career and the future of planetary science, came to the USA and to Robert Cashman's laboratory at Northwestern University. As the war was winding down, Cashman and Kuiper worked together to develop a practical infrared spectrometer for astronomical use. Within months, Kuiper discovered the C02 atmospheres on Mars and Venus.

  5. Collisions in the Kuiper belt

    NASA Astrophysics Data System (ADS)

    Brown, Michael

    2007-07-01

    For most of the 15 year history of observations of Kuiper belt objects, it has been speculated that impacts must have played a major role in shaping the physical and chemical characteristics of these objects, yet little direct evidence of the effects of such impacts has been seen. The past 18 months, however, have seen an explosion of major new discoveries giving some of the first insights into the influence of this critical process. From a diversity of observations we have been led to the hypotheses that: {1} satellite-forming impacts must have been common in the Kuiper belt; {2} such impacts led to significant chemical modification; and {3} the outcomes of these impacts are sufficiently predictable that we can now find and study these impact-derived systems by the chemical and physical attributes of both the satellites and the primaries. If our picture is correct, we now have in hand for the first time a set of incredibly powerful tools to study the frequency and outcome of collisions in the outer solar system. Here we propose three linked projects that would answer questions critical to the multiple prongs of our hypothesis. In these projects we will study the chemical effects of collisions through spectrophotometric observations of collisionally formed satellites and through the search for additional satellites around primaries with potential impact signatures, and we will study the physical effects of impacts through the examination of tidal evolution in proposed impact systems. The intensive HST program that we propose here will allow us to fully test our new hypotheses and will provide the ability to obtain the first extensive insights into outer solar system impact processes.

  6. A Search for 23rd Magnitude Kuiper Belt Comets

    NASA Technical Reports Server (NTRS)

    Luu, Jane

    1997-01-01

    The goal of the project was to identify a statistically significant sample of large (200 km-sized) Kuiper Belt Objects (KBOs), by covering 10 sq. degrees of the sky to a red limiting magnitude m(sub R) = 23. This work differs from, but builds on, previous surveys of the outer solar system in that it will cover a large area to a limiting magnitude that is deep enough to guarantee positive results. The proposed work should provide us with a significant number of 200 km-size KBOs (approx. 20 are expected) for subsequent studies. Such a sample is crucial if we are to investigate the statistical properties of the Belt and its members. It was modified the original research strategy to accommodate unanticipated problems such as the urgent need for follow-up observations,the original goal was still reached: we have substantially increased the number of Kuiper Belt Objects brighter than 23rd mag.

  7. Water Ice on Kuiper Belt Object 1996 TO66

    NASA Technical Reports Server (NTRS)

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

    1999-01-01

    The 1.40-2.40 micron spectrum of Kuiper Belt object (KBO) 1996 TO66 was measured at the Keck Observatory in September 1998. It's spectrum shows the strong absorptions near 1.5 and 2.0 micron characteristic of water ice--the first such detection on a Kuiper Belt object. The depth of the absorption bands and the continuum reflectance of 1996 TO66 also suggest the presence of a black to slightly blue-colored, spectrally featureless particulate material as a minority component mixed with the water ice. In addition, there is evidence that the intensity of the water bands in the spectrum of 1996 TO66 vary with rotational phase suggesting that it has a "patchy" surface.

  8. 20 CFR 664.100 - What is the youth council?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...) and 20 CFR 661.335 and 661.340. (b) The purpose of the youth council is to provide expertise in youth... training policy and practice; (2) Broadening the youth employment and training focus in the community...

  9. 20 CFR 641.100 - What does this part cover?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... efforts to provide services through the integration of the SCSEP within the One-Stop Delivery System. (c... GOVERNING THE SENIOR COMMUNITY SERVICE EMPLOYMENT PROGRAM Purpose and Definitions § 641.100 What does this part cover? Part 641 contains the Department of Labor's regulations for the Senior Community...

  10. 20 CFR 641.100 - What does this part cover?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... GOVERNING THE SENIOR COMMUNITY SERVICE EMPLOYMENT PROGRAM Purpose and Definitions § 641.100 What does this part cover? Part 641 contains the Department of Labor's regulations for the Senior Community Service... required relationship between the OAA and the Workforce Investment Act of 1998 (WIA), 29 U.S.C. 2801 et...

  11. 20 CFR 439.100 - What does this part do?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... out the portion of the Drug-Free Workplace Act of 1988 (41 U.S.C. 701 et seq., as amended) that....100 Employees' Benefits SOCIAL SECURITY ADMINISTRATION GOVERNMENTWIDE REQUIREMENTS FOR DRUG-FREE... assistance awards, as a matter of Federal Government policy....

  12. 20 CFR 645.100 - What does this part cover?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... GOVERNING WELFARE-TO-WORK GRANTS Scope and Purpose § 645.100 What does this part cover? (a) Subpart A establishes regulatory provisions that apply to the Welfare-to-Work (WtW) programs conducted at the State and...) Regulatory provisions applicable to the Indian and Native American Welfare-to-Work Program (INA WtW)...

  13. Collisional Time Scales in the Kuiper Disk and Their Implications

    NASA Technical Reports Server (NTRS)

    Stern, S. Alan

    1995-01-01

    We explore the rate of collisions among bodies in the present-day Kuiper Disk as a function of the total mass and population size structure of the disk. We find that collisional evolution is an important evolutionary process in the disk as a whole, and indeed, that it is likely the dominant evolutionary process beyond approx. 42 AU, where dynamical instability time scales exceed the age of the solar system. Two key findings we report from this modeling work are: that unless the disk's population structure is sharply truncated for radii smaller than approx. 1-2 km, collisions between comets and smaller debris are occurring so frequently in the disk, and with high enough velocities, that the small body (i.e., KM-class object) population in the disk has probably developed into a collisional cascade, thereby implying that the Kuiper Disk comets may not all be primordial, and that the rate of collisions of smaller bodies with larger 100 less R less 400 km objects (like 1992QB(sub 1) and its cohorts) is so low that there appears to be a dilemma in explaining how QB(sub 1)s could have grown by binary accretion in the disk as we know it. Given these findings, it appears that either the present-day paradigm for the formation of Kuiper Disk is failed in some fundamental respect, or that the present-day disk is no longer representative of the ancient structure from which it evolved. This in turn suggests the intriguing possibility that the present-day Kuiper Disk evolved through a more erosional stage reminiscent of the disks around the stars Beta Pictorus, alpha PsA, and alpha Lyr.

  14. Structure of the atmosphere of Venus up to 110 kilometers: Preliminary results from the four Pioneer Venus entry probes

    USGS Publications Warehouse

    Seiff, A.; Kirk, D.B.; Sommer, S.C.; Young, R.E.; Blanchard, R.C.; Juergens, D.W.; Lepetich, J.E.; Intrieri, P.F.; Findlay, J.T.; Derr, J.S.

    1979-01-01

    The four Pioneer Venus entry probes transmitted data of good quality on the structure of the atmosphere below the clouds. Contrast of the structure below an altitude of 50 kilometers at four widely separated locations was found to be no more than a few degrees Kelvin, with slightly warmer temperatures at 30?? south latitude than at 5?? or 60?? north. The atmosphere was stably stratified above 15 or 20 kilometers, indicating that the near-adiabatic state is maintained by the general circulation. The profiles move from near-adiabatic toward radiative equilibrium at altitudes above 40 kilometers. There appears to be a region of vertical convection above the dense cloud deck, which lies at 47.5 to 49 kilometers and at temperature levels near 360 K. The atmosphere is nearly isothermal around 100 kilometers (175 to 180 K) and appears to exhibit a sizable temperature wave between 60 and 70 kilometers. This is where the 4-day wind is believed to occur. The temperature wave may be related to some of the wavelike phenomena seen in Mariner 10 ultraviolet photographs. Copyright ?? 1979 AAAS.

  15. Three steps toward understanding the dynamical structure of the Kuiper belt (and what it means for Neptune's migration)

    NASA Astrophysics Data System (ADS)

    Nesvorny, David

    2015-11-01

    Much of the dynamical structure of the Kuiper belt can be explained if Neptune migrated over several AU, and/or if Neptune was scattered to an eccentric orbit during planetary instability.Step 1: An outstanding problem with the previous migration/instability models is that the distribution of orbital inclinations they predict is narrower than the one inferred from observations. Here we perform numerical simulations of the Kuiper belt formation starting from an initial state with Neptune at 20100 Myr. A small fraction of the disk planetesimals become implanted into the Kuiper belt in the simulations. We find that the inclination constraint implies that Neptune's migration was slow (tau > 10 Myr) and long range (a_N < 25 AU).Step 2: A particularly puzzling and up-to-now unexplained feature of the Kuiper belt is the so-called `kernel', a concentration of orbits with semimajor axes a=44 AU, eccentricities e=0.05, and inclinations i<5 deg. Here we show that the Kuiper belt kernel can be explained if Neptune's migration was interrupted by a discontinuous change of Neptune's semimajor axis when Neptune reached 28 AU (jumping-Neptune model).Step 3: The existing migration/instability models invariably predict an excessively large resonant population, while observations show that the non-resonant orbits are in fact more common (e.g., Plutinos in the 3:2 resonance represent only ~1/3 of the main belt population). Here we show that the observed population statistic implies that Neptune's migration was grainy, as expected from scattering encounters of Neptune with massive planetesimals. Our preferred fit to observations suggests that the outer planetesimal disk below 30 AU contained ~2000 bodies with mass comparable to that of Pluto.Together, these results imply that Neptune's migration was slow, long-range and grainy

  16. Phobos from 6,800 Kilometers (Color)

    NASA Technical Reports Server (NTRS)

    2008-01-01

    [figure removed for brevity, see original site] Inset

    The High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter took two images of the larger of Mars' two moons, Phobos, within 10 minutes of each other on March 23, 2008. This is the first, taken from a distance of about 6,800 kilometers (about 4,200 miles). It is presented in color by combining data from the camera's blue-green, red, and near-infrared channels.

    The illuminated part of Phobos seen in the images is about 21 kilometers (13 miles) across. The most prominent feature in the images is the large crater Stickney in the lower right. With a diameter of 9 kilometers (5.6 miles), it is the largest feature on Phobos.

    The color data accentuate details not apparent in black-and-white images. For example, materials near the rim of Stickney appear bluer than the rest of Phobos. Based on analogy with materials on our own moon, this could mean this surface is fresher, and therefore younger, than other parts of Phobos.

    A series of troughs and crater chains is obvious on other parts of the moon. Although many appear radial to Stickney in this image, recent studies from the European Space Agency's Mars Express orbiter indicate that they are not related to Stickney. Instead, they may have formed when material ejected from impacts on Mars later collided with Phobos. The lineated textures on the walls of Stickney and other large craters are landslides formed from materials falling into the crater interiors in the weak Phobos gravity (less than one one-thousandth of the gravity on Earth).

    In the full-resolution version of this image, a pixel encompasses 6.8 meters (22 feet), providing a resolution (smallest visible feature) of about 20 meters (about 65 feet). The image is in the HiRISE catalog as PSP_007769_9010.

    NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Mars Reconnaissance

  17. Phobos from 6,800 Kilometers

    NASA Technical Reports Server (NTRS)

    2008-01-01

    The High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter took two images of the larger of Mars' two moons, Phobos, within 10 minutes of each other on March 23, 2008. This is the first, taken from a distance of about 6,800 kilometers (about 4,200 miles). The illuminated part of Phobos seen in the images is about 21 kilometers (13 miles) across.

    The most prominent feature in the images is the large crater Stickney in the lower right. With a diameter of 9 kilometers (5.6 miles), it is the largest feature on Phobos. A series of troughs and crater chains is obvious on other parts of the moon. Although many appear radial to Stickney in this image, recent studies from the European Space Agency's Mars Express orbiter indicate that they are not related to Stickney. Instead, they may have formed when material ejected from impacts on Mars later collided with Phobos. The lineated textures on the walls of Stickney and other large craters are landslides formed from materials falling into the crater interiors in the weak Phobos gravity (less than one one-thousandth of the gravity on Earth).

    In the full-resolution version of this image, a pixel encompasses 6.8 meters (22 feet), providing a resolution (smallest visible feature) of about 20 meters (about 65 feet). Although the image is displayed here in black and white, data from HiRISE's three color channels were used to give higher signal-to-noise, thereby increasing detail. The image is in the HiRISE catalog as PSP_007769_9010.

    NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Mars Reconnaissance Orbiter for NASA's Science Mission Directorate, Washington. Lockheed Martin Space Systems, Denver, is the prime contractor for the project and built the spacecraft. The High Resolution Imaging Science Experiment is operated by the University of Arizona, Tucson, and the instrument was built by Ball Aerospace

  18. OORT-Cloud and Kuiper-Belt Comets

    NASA Technical Reports Server (NTRS)

    Whipple, Fred L.

    1998-01-01

    This paper follows the broadly accepted theory that Oort-Cloud Comets originated in the Solar Nebula in the general region where the major planets, Jupiter and Saturn, were formed while the Kuiper-Belt Comets originated farther out where the temperatures were lower. The Oort-Cloud Comets are identified orbitally by long periods and random inclinations and, including the Halley-type comets, comets with a Tisserand Criterion less than 2.0. Kuiper-Belt comets are identified by short periods, usually much less than 200 years, and small inclinations to the ecliptic. Here two criteria for comet activity are found to separate the two classes of comets. These quantities NG1 and NG2, were intended to measure theoretical nongravitaional effects on comet orbits. They are only, mildly successful in correlations with observed cases of measured non-gravitational forces. But, in fact, their variations with perihelion distance separate the two classes of comets. The results are consistent with the theory that the activity or intrinsic brightness of Oort-Cloud Comets fall off faster with increasing perihelion distance that does the intrinsic brightness of short-period Kuiper-Belt Comets.

  19. [The 20th century: 100 years of misfortune and splendor].

    PubMed

    Urdaneta-Carruyo, Eliéxer

    2005-01-01

    The 20th century has been one of the most intense and convulsive periods in the History of humanity. A century of paradoxes and contrasts, it began with optimism, it witnessed the apocalypse of two world wars, and finished with unimaginable scientific progress that gave us a new civilization that we cannot yet grasp. In this century, significant events happened that shaped our time and projected their results toward an immediate future. Some of these were providential in understanding man's life, fighting against illnesses and prolonging life, and others were of undeniable social importance for humanity. Some knowledge was based on the work of others. Philosophy was embedded in mathematics, as was science in philosophy, while politics and the economy exercised so decisive an influence in our way of feeling and living that culture and society were affected to the core. Within that century the biggest technological revolution of all the time was also created, as transcendent as it was unimaginable, which put mankind on the road to the stars with the moon landing and in the process created the information society whose signature symbol, the internet, emerged as a new demiurge. However, the 20th century, with all its misfortune and splendor, paradoxes and contrasts, creation and destruction, was the most transcendent in the whole of history and it bequeaths to the future a promising horizon in the search for a renovated meaning of life and a yearning for peaceful coexistence for the whole humanity. PMID:15754756

  20. 11 CFR 100.20 - Occupation (2 U.S.C. 431(13)).

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 11 Federal Elections 1 2010-01-01 2010-01-01 false Occupation (2 U.S.C. 431(13)). 100.20 Section 100.20 Federal Elections FEDERAL ELECTION COMMISSION GENERAL SCOPE AND DEFINITIONS (2 U.S.C. 431) General Definitions § 100.20 Occupation (2 U.S.C. 431(13)). Occupation means the principal job title...

  1. 11 CFR 100.20 - Occupation (2 U.S.C. 431(13)).

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 11 Federal Elections 1 2011-01-01 2011-01-01 false Occupation (2 U.S.C. 431(13)). 100.20 Section 100.20 Federal Elections FEDERAL ELECTION COMMISSION GENERAL SCOPE AND DEFINITIONS (2 U.S.C. 431) General Definitions § 100.20 Occupation (2 U.S.C. 431(13)). Occupation means the principal job title...

  2. The state of knowledge concerning the Kuiper belt

    NASA Technical Reports Server (NTRS)

    Levison, Harold F.

    1992-01-01

    The arguments for and against the idea that most short-period comets originate in the Kuiper belt are discussed. Observational constraints on the distribution of mass in the Kuiper belt are reviewed as well as a model of the physical conditions that now exist. Finally, predictions from this model about the detectability of the Kuiper belt are compared to optical surveys.

  3. UNBIASED INCLINATION DISTRIBUTIONS FOR OBJECTS IN THE KUIPER BELT

    SciTech Connect

    Gulbis, A. A. S.; Elliot, J. L.; Adams, E. R.; Benecchi, S. D.; Buie, M. W.; Trilling, D. E.; Wasserman, L. H. E-mail: jle@mit.ed E-mail: lhw@lowell.ed E-mail: buie@boulder.swri.ed

    2010-08-15

    Using data from the Deep Ecliptic Survey (DES), we investigate the inclination distributions of objects in the Kuiper Belt. We present a derivation for observational bias removal and use this procedure to generate unbiased inclination distributions for Kuiper Belt objects (KBOs) of different DES dynamical classes, with respect to the Kuiper Belt plane. Consistent with previous results, we find that the inclination distribution for all DES KBOs is well fit by the sum of two Gaussians, or a Gaussian plus a generalized Lorentzian, multiplied by sin i. Approximately 80% of KBOs are in the high-inclination grouping. We find that Classical object inclinations are well fit by sin i multiplied by the sum of two Gaussians, with roughly even distribution between Gaussians of widths 2.0{sup +0.6}{sub -0.5}{sup 0} and 8.1{sup +2.6}{sub -2.1}{sup 0}. Objects in different resonances exhibit different inclination distributions. The inclinations of Scattered objects are best matched by sin i multiplied by a single Gaussian that is centered at 19.1{sup +3.9}{sub -3.6}{sup 0} with a width of 6.9{sup +4.1}{sub -2.7}{sup 0}. Centaur inclinations peak just below 20{sup 0}, with one exceptionally high-inclination object near 80{sup 0}. The currently observed inclination distribution of the Centaurs is not dissimilar to that of the Scattered Extended KBOs and Jupiter-family comets, but is significantly different from the Classical and Resonant KBOs. While the sample sizes of some dynamical classes are still small, these results should begin to serve as a critical diagnostic for models of solar system evolution.

  4. 28 CFR 100.20 - Confidentiality of trade secrets/proprietary information.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 28 Judicial Administration 2 2011-07-01 2011-07-01 false Confidentiality of trade secrets/proprietary information. 100.20 Section 100.20 Judicial Administration DEPARTMENT OF JUSTICE (CONTINUED) COST... trade secrets/proprietary information. With respect to any information provided to the FBI under...

  5. 28 CFR 100.20 - Confidentiality of trade secrets/proprietary information.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 28 Judicial Administration 2 2010-07-01 2010-07-01 false Confidentiality of trade secrets/proprietary information. 100.20 Section 100.20 Judicial Administration DEPARTMENT OF JUSTICE (CONTINUED) COST... trade secrets/proprietary information. With respect to any information provided to the FBI under...

  6. 28 CFR 100.20 - Confidentiality of trade secrets/proprietary information.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 28 Judicial Administration 2 2013-07-01 2013-07-01 false Confidentiality of trade secrets/proprietary information. 100.20 Section 100.20 Judicial Administration DEPARTMENT OF JUSTICE (CONTINUED) COST... trade secrets/proprietary information. With respect to any information provided to the FBI under...

  7. 28 CFR 100.20 - Confidentiality of trade secrets/proprietary information.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 28 Judicial Administration 2 2014-07-01 2014-07-01 false Confidentiality of trade secrets/proprietary information. 100.20 Section 100.20 Judicial Administration DEPARTMENT OF JUSTICE (CONTINUED) COST... trade secrets/proprietary information. With respect to any information provided to the FBI under...

  8. 28 CFR 100.20 - Confidentiality of trade secrets/proprietary information.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 28 Judicial Administration 2 2012-07-01 2012-07-01 false Confidentiality of trade secrets/proprietary information. 100.20 Section 100.20 Judicial Administration DEPARTMENT OF JUSTICE (CONTINUED) COST... trade secrets/proprietary information. With respect to any information provided to the FBI under...

  9. Cdc20 mediates D-box-dependent degradation of Sp100

    SciTech Connect

    Wang, Ran; Li, Ke-min; Zhou, Cai-hong; Xue, Jing-lun; Ji, Chao-neng; Chen, Jin-zhong

    2011-12-02

    Highlights: Black-Right-Pointing-Pointer Cdc20 is a co-activator of APC/C complex. Black-Right-Pointing-Pointer Cdc20 recruits Sp100 and mediates its degradation. Black-Right-Pointing-Pointer The D-box of Sp100 is required for Cdc20-mediated degradation. Black-Right-Pointing-Pointer Sp100 expresses consistently at both the mRNA and protein levels in cell cycle. -- Abstract: Cdc20 is a co-activator of the anaphase-promoting complex/cyclosome (APC/C complex), which recruits substrates at particular phases of the cell cycle and mediates their degradation. Sp100 is a PML-NB scaffold protein, which localizes to nuclear particles during interphase and disperses from them during mitosis, participates in viral resistance, transcriptional regulation, and apoptosis. However, its metabolism during the cell cycle has not yet been fully characterized. We found a putative D-box in Sp100 using the Eukaryotic Linear Motif (ELM) predictor database. The putative D-box of Sp100 was verified by mutational analysis. Overexpression of Cdc20 resulted in decreased levels of both endogenous Sp100 protein and overexpressed Sp100 mRNA in HEK 293 cells. Only an overexpressed D-box deletion mutant of Sp100 accumulated in HEK293 cells that also overexpressed Cdc20. Cdc20 knockdown by cdc20 specific siRNA resulted in increased Sp100 protein levels in cells. Furthermore, we discovered that the Cdc20 mediated degradation of Sp100 is diminished by the proteasome inhibitor MG132, which suggests that the ubiquitination pathway is involved in this process. However, unlike the other Cdc20 substrates, which display oscillating protein levels, the level of Sp100 protein remains constant throughout the cell cycle. Additionally, both overexpression and knockdown of endogenous Sp100 had no effect on the cell cycle. Our results suggested that sp100 is a novel substrate of Cdc20 and it is degraded by the ubiquitination pathway. The intact D-box of Sp100 was necessary for this process. These findings expand

  10. 20 CFR 666.100 - What performance indicators must be included in a State's plan?

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 20 Employees' Benefits 4 2013-04-01 2013-04-01 false What performance indicators must be included in a State's plan? 666.100 Section 666.100 Employees' Benefits EMPLOYMENT AND TRAINING ADMINISTRATION... State Measures of Performance § 666.100 What performance indicators must be included in a State's...

  11. 20 CFR 10.0 - What are the provisions of the FECA, in general?

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 20 Employees' Benefits 1 2012-04-01 2012-04-01 false What are the provisions of the FECA, in general? 10.0 Section 10.0 Employees' Benefits OFFICE OF WORKERS' COMPENSATION PROGRAMS, DEPARTMENT OF...' COMPENSATION ACT, AS AMENDED General Provisions Introduction § 10.0 What are the provisions of the FECA,...

  12. 20 CFR 10.0 - What are the provisions of the FECA, in general?

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 20 Employees' Benefits 1 2014-04-01 2012-04-01 true What are the provisions of the FECA, in general? 10.0 Section 10.0 Employees' Benefits OFFICE OF WORKERS' COMPENSATION PROGRAMS, DEPARTMENT OF...' COMPENSATION ACT, AS AMENDED General Provisions Introduction § 10.0 What are the provisions of the FECA,...

  13. 20 CFR 628.100 - Scope and purpose of part 628.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 20 Employees' Benefits 3 2012-04-01 2012-04-01 false Scope and purpose of part 628. 628.100 Section 628.100 Employees' Benefits EMPLOYMENT AND TRAINING ADMINISTRATION, DEPARTMENT OF LABOR PROGRAMS UNDER TITLE II OF THE JOB TRAINING PARTNERSHIP ACT Scope and Purpose § 628.100 Scope and purpose of part 628. (a) This part sets forth requirements...

  14. 20 CFR 666.100 - What performance indicators must be included in a State's plan?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 20 Employees' Benefits 3 2011-04-01 2011-04-01 false What performance indicators must be included in a State's plan? 666.100 Section 666.100 Employees' Benefits EMPLOYMENT AND TRAINING ADMINISTRATION... of Performance § 666.100 What performance indicators must be included in a State's plan? (a)...

  15. Pluto's small satellites in the context of the Kuiper Belt

    NASA Astrophysics Data System (ADS)

    Parker, A. H.; Weaver, H. A., Jr.; Porter, S.; Spencer, J. R.; Olkin, C.; Howett, C.; Grundy, W. M.; Buie, M. W.

    2015-12-01

    New Horizons is now beyond Pluto and flying deeper into the Kuiper Belt. The small satellites in the Pluto system are the closest analogues to typical Kuiper Belt Objects yet observed at close-range by the spacecraft, and we will review these observations in the greater context of the Kuiper Belt and as they pertain to New Horizons' exploration of a similarly-sized classical Kuiper Belt target in late 2018 or early 2019. Finally, we will summarize the current state-of-knowledge regarding the potential long-range and close-range Kuiper Belt targets.

  16. G. P. Kuiper's Early Studies of Planets

    NASA Astrophysics Data System (ADS)

    Cruikshank, D. P.

    2005-08-01

    Gerard P. Kuiper was born on December 7, 1905; this is his centennial year. While he had an early interest in Solar System bodies, writing an extensive review about Mars for the popular Dutch astronomy journal, Hemel en Dampkring in 1931, Kuiper's first important observations began in 1944, when he discovered the atmosphere of Titan. In a letter dated February 29, 1944, to Lick Observatory director Joseph H. Moore, Kuiper noted that, ``The only reason I happened to observe the planets and the 10 brightest satellites was that they were nicely lined up in a region of the sky where I had run out of program stars (stars of large proper motion and parallax)." These spectroscopic observations were obtained with the new McDonald 82-inch telescope during a break from Kuiper's war-time work at Harvard's Radio Research Laboratory. In a letter of congratulations, his friend S. Chandrasekhar wrote, ``It is only on the impact of such discoveries that one realizes afresh the permanent value of science which no war -- not even of Hitler's -- can truly undermine. And it must be of satisfaction to you that if you took a vacation from war-work, it was only to make a fundamental discovery!" Using detectors declassified at the end of World War II, Kuiper began a study of the infrared spectra of planets and stars (with the first publication in 1947) that continued to the time of his death (December 24, 1973). Early in this work, on March 2, 1948, he wrote a lengthy letter to Henry Norris Russell in which he succinctly and enthusiastically summarized his observations and discoveries. Details in this letter give a fascinating perspective on some of the earliest physical studies of Solar System bodies, such as the detection of water ice on Saturn's rings and in the polar cap of Mars, spectral and photometric measurements of Mars' surface and atmospheric haze, and the discovery of Miranda.

  17. Kuiper Belt Dust Grains as a Source of Interplanetary Dust Particles

    NASA Technical Reports Server (NTRS)

    Liou, Jer-Chyi; Zook, Herbert A.; Dermott, Stanley F.

    1996-01-01

    The recent discovery of the so-called Kuiper belt objects has prompted the idea that these objects produce dust grains that may contribute significantly to the interplanetary dust population. In this paper, the orbital evolution of dust grains, of diameters 1 to 9 microns, that originate in the region of the Kuiper belt is studied by means of direct numerical integration. Gravitational forces of the Sun and planets, solar radiation pressure, as well as Poynting-Robertson drag and solar wind drag are included. The interactions between charged dust grains and solar magnetic field are not considered in the model. Because of the effects of drag forces, small dust grains will spiral toward the Sun once they are released from their large parent bodies. This motion leads dust grains to pass by planets as well as encounter numerous mean motion resonances associated with planets. Our results show that about 80% of the Kuiper belt grains are ejected from the Solar System by the giant planets, while the remaining 20% of the grains evolve all the way to the Sun. Surprisingly, the latter dust grains have small orbital eccentricities and inclinations when they cross the orbit of the Earth. This makes them behave more like asteroidal than cometary-type dust particles. This also enhances their chances of being captured by the Earth and makes them a possible source of the collected interplanetary dust particles; in particular, they represent a possible source that brings primitive/organic materials from the outer Solar System to the Earth. When collisions with interstellar dust grains are considered, however, Kuiper belt dust grains around 9 microns appear likely to be collisionally shattered before they can evolve toward the inner part of the Solar System. The collision destruction can be applied to Kuiper belt grains up to about 50 microns. Therefore, Kuiper belt dust grains within this range may not be a significant part of the interplanetary dust complex in the inner Solar

  18. 20 CFR 655.100 - Scope and purpose of subpart B.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false Scope and purpose of subpart B. 655.100... Employment in the United States (H-2A Workers) § 655.100 Scope and purpose of subpart B. This subpart sets... import nonimmigrant foreign workers (H-2A workers); and (b) Whether the employment of H-2A workers...

  19. 20 CFR 10.0 - What are the provisions of the FECA, in general?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 20 Employees' Benefits 1 2011-04-01 2011-04-01 false What are the provisions of the FECA, in general? 10.0 Section 10.0 Employees' Benefits OFFICE OF WORKERS' COMPENSATION PROGRAMS, DEPARTMENT OF LABOR FEDERAL EMPLOYEES' COMPENSATION ACT CLAIMS FOR COMPENSATION UNDER THE FEDERAL...

  20. 20 CFR 10.100 - How and when is a notice of traumatic injury filed?

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 20 Employees' Benefits 1 2013-04-01 2012-04-01 true How and when is a notice of traumatic injury filed? 10.100 Section 10.100 Employees' Benefits OFFICE OF WORKERS' COMPENSATION PROGRAMS, DEPARTMENT OF LABOR FEDERAL EMPLOYEES' COMPENSATION ACT CLAIMS FOR COMPENSATION UNDER THE FEDERAL...

  1. 20 CFR 661.100 - What is the workforce investment system?

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 20 Employees' Benefits 4 2014-04-01 2014-04-01 false What is the workforce investment system? 661.100 Section 661.100 Employees' Benefits EMPLOYMENT AND TRAINING ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) STATEWIDE AND LOCAL GOVERNANCE OF THE WORKFORCE INVESTMENT SYSTEM UNDER TITLE I OF THE...

  2. 20 CFR 10.0 - What are the provisions of the FECA, in general?

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 20 Employees' Benefits 1 2013-04-01 2012-04-01 true What are the provisions of the FECA, in general? 10.0 Section 10.0 Employees' Benefits OFFICE OF WORKERS' COMPENSATION PROGRAMS, DEPARTMENT OF LABOR FEDERAL EMPLOYEES' COMPENSATION ACT CLAIMS FOR COMPENSATION UNDER THE FEDERAL...

  3. 20 CFR 10.100 - How and when is a notice of traumatic injury filed?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 20 Employees' Benefits 1 2011-04-01 2011-04-01 false How and when is a notice of traumatic injury filed? 10.100 Section 10.100 Employees' Benefits OFFICE OF WORKERS' COMPENSATION PROGRAMS, DEPARTMENT OF LABOR FEDERAL EMPLOYEES' COMPENSATION ACT CLAIMS FOR COMPENSATION UNDER THE FEDERAL...

  4. 20 CFR 667.100 - When do Workforce Investment Act grant funds become available?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 20 Employees' Benefits 3 2011-04-01 2011-04-01 false When do Workforce Investment Act grant funds become available? 667.100 Section 667.100 Employees' Benefits EMPLOYMENT AND TRAINING ADMINISTRATION... April 1 of the fiscal year for which the appropriation is made....

  5. 20 CFR 667.100 - When do Workforce Investment Act grant funds become available?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false When do Workforce Investment Act grant funds become available? 667.100 Section 667.100 Employees' Benefits EMPLOYMENT AND TRAINING ADMINISTRATION... April 1 of the fiscal year for which the appropriation is made....

  6. 46 CFR 42.20-8 - Flooding standard: Type “B” vessel, 100 percent reduction.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 2 2012-10-01 2012-10-01 false Flooding standard: Type âBâ vessel, 100 percent... LINES DOMESTIC AND FOREIGN VOYAGES BY SEA Freeboards § 42.20-8 Flooding standard: Type “B” vessel, 100...-11 as applied to the following flooding standards: (1) If the vessel is 225 meters (738 feet) or...

  7. 46 CFR 42.20-8 - Flooding standard: Type “B” vessel, 100 percent reduction.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 2 2011-10-01 2011-10-01 false Flooding standard: Type âBâ vessel, 100 percent... LINES DOMESTIC AND FOREIGN VOYAGES BY SEA Freeboards § 42.20-8 Flooding standard: Type “B” vessel, 100...-11 as applied to the following flooding standards: (1) If the vessel is 225 meters (738 feet) or...

  8. 46 CFR 42.20-8 - Flooding standard: Type “B” vessel, 100 percent reduction.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 2 2014-10-01 2014-10-01 false Flooding standard: Type âBâ vessel, 100 percent... LINES DOMESTIC AND FOREIGN VOYAGES BY SEA Freeboards § 42.20-8 Flooding standard: Type “B” vessel, 100...-11 as applied to the following flooding standards: (1) If the vessel is 225 meters (738 feet) or...

  9. 46 CFR 42.20-8 - Flooding standard: Type “B” vessel, 100 percent reduction.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Flooding standard: Type âBâ vessel, 100 percent... LINES DOMESTIC AND FOREIGN VOYAGES BY SEA Freeboards § 42.20-8 Flooding standard: Type “B” vessel, 100...-11 as applied to the following flooding standards: (1) If the vessel is 225 meters (738 feet) or...

  10. 46 CFR 42.20-8 - Flooding standard: Type “B” vessel, 100 percent reduction.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 2 2013-10-01 2013-10-01 false Flooding standard: Type âBâ vessel, 100 percent... LINES DOMESTIC AND FOREIGN VOYAGES BY SEA Freeboards § 42.20-8 Flooding standard: Type “B” vessel, 100...-11 as applied to the following flooding standards: (1) If the vessel is 225 meters (738 feet) or...

  11. QUAOAR: A ROCK IN THE KUIPER BELT

    SciTech Connect

    Fraser, Wesley C.; Brown, Michael E.

    2010-05-10

    Here we report Wide-Field Planetary Camera 2 observations of the Quaoar-Weywot Kuiper Belt binary. From these observations, we find that Weywot is on an elliptical orbit with an eccentricity of 0.14 {+-} 0.04, a period of 12.438 {+-} 0.005 days, and a semimajor axis of 1.45 {+-} 0.08 x 10{sup 4} km. The orbit reveals a surprisingly high-Quaoar-Weywot system mass of (1.6 {+-} 0.3) x 10{sup 21} kg. Using the surface properties of the Uranian and Neptunian satellites as a proxy for Quaoar's surface, we reanalyze the size estimate from Brown and Trujillo. We find, from a mean of available published size estimates, a diameter for Quaoar of 890 {+-} 70 km. We find Quaoar's density to be {rho} = 4.2 {+-} 1.3gcm{sup -3}, possibly the highest density in the Kuiper Belt.

  12. Far-Infrared Polarimetry of Galactic Clouds from the Kuiper Airborne Observatory

    NASA Technical Reports Server (NTRS)

    Dotson, Jessie L.; Davidson, Jacqueline; Dowell, C. Darren; Schleuning, David A.; Hildebrand, Roger H.

    1999-01-01

    In this paper we present a complete summary of the data obtained with the far-infrared polarimeter, Stokes, in flights of the Kuiper Airborne Observatory. We have observed 12 Galactic clouds and have made over 1100 individual measurements at 100 micrometer and 60 micrometer. The median P for all of the 60 micrometer and 100 micrometer measurements is 3.6% and 2.6% respectively. We also present flux maps obtained simultaneously with the polarimetry.

  13. IDENTIFYING COLLISIONAL FAMILIES IN THE KUIPER BELT

    SciTech Connect

    Marcus, Robert A.; Ragozzine, Darin; Murray-Clay, Ruth A.; Holman, Matthew J.

    2011-05-20

    The identification and characterization of numerous collisional families-clusters of bodies with a common collisional origin-in the asteroid belt has added greatly to the understanding of asteroid belt formation and evolution. More recent study has also led to an appreciation of physical processes that had previously been neglected (e.g., the Yarkovsky effect). Collisions have certainly played an important role in the evolution of the Kuiper Belt as well, though only one collisional family has been identified in that region to date, around the dwarf planet Haumea. In this paper, we combine insights into collisional families from numerical simulations with the current observational constraints on the dynamical structure of the Kuiper Belt to investigate the ideal sizes and locations for identifying collisional families. We find that larger progenitors (r {approx} 500 km) result in more easily identifiable families, given the difficulty in identifying fragments of smaller progenitors in magnitude-limited surveys, despite their larger spread and less frequent occurrence. However, even these families do not stand out well from the background. Identifying families as statistical overdensities is much easier than characterizing families by distinguishing individual members from interlopers. Such identification seems promising, provided the background population is well known. In either case, families will also be much easier to study where the background population is small, i.e., at high inclinations. Overall, our results indicate that entirely different techniques for identifying families will be needed for the Kuiper Belt, and we provide some suggestions.

  14. The gravitational sculpting of the Kuiper belt

    NASA Astrophysics Data System (ADS)

    Levison, H. F.; Duncan, M. J.

    1993-03-01

    Results are presented of numerical integrations over billion year time scales of the orbital evolution of more than one thousand test particles on initially low-inclination, low-eccentricity orbits within the proposed Kuiper belt beyond Neptune. Particles which eventually crossed Neptune's orbit often showed long periods (up to several billion years) of relatively low-eccentricity oscillations punctuated by a very rapid jump to Neptune-crossing eccentricity. This flux may be the ultimate source of present-day short-period comets. It is found here that there exists a correlation between Liapunov and crossing times in the Kuiper belt. None of the particles in the study with Liapunov time scales greater than about 1 Myr actually became a Neptune-crosser in 4 Gyr. An intricate structure to the region between 35 and 45 AU is found at the end of the billion year simulation. Implications for the origins of short-period comets and the detectability of objects currently in the Kuiper belt are discussed.

  15. The Kuiper Belt of Four Gigayears Ago

    NASA Astrophysics Data System (ADS)

    Malhotra, Renu

    2008-09-01

    The Kuiper belt is largely dynamically stable on gigayear timescales, but weak orbital instabilities - also known as chaotic diffusion - have eroded its population by several tens of percent over the past 4 gigayears. Each of the dynamical subclasses in the Kuiper belt has slightly different loss rates. In this paper, I reconstruct the populations of the different subclasses as they were 4 gigayears ago, an epoch when the presently observed dynamical structure is thought to have been established. This exercise shows that the resonant/classical population ratio was significantly higher in the past, as also the scattered/classical population ratio; the resonant Twotino/Plutino population ratio was also much greater in the past. Such a historical projection is necessary for testing and constraining theories for the origin of the dynamical structure of the Kuiper belt. The differential loss rates of the various KB dynamical classes are also of interest for understanding the sources of impactors that are recorded in the impact craters on solid planetary bodies, as well as for establishing the provenance of transient small bodies, such as the Centaurs and the Jupiter family comets. This research was supported in part by grants from NASA's Origins of Solar Systems and Outer Planets Research programs.

  16. CHAOTIC DIFFUSION OF RESONANT KUIPER BELT OBJECTS

    SciTech Connect

    Tiscareno, Matthew S.; Malhotra, Renu

    2009-09-15

    We carried out extensive numerical orbit integrations to probe the long-term chaotic dynamics of the two strongest mean-motion resonances of Neptune in the Kuiper Belt, the 3:2 (Plutinos) and 2:1 (Twotinos). Our primary results include a computation of the relative volumes of phase space characterized by large- and small-resonance libration amplitudes, and maps of resonance stability measured by mean chaotic diffusion rate. We find that Neptune's 2:1 resonance has weaker overall long-term stability than the 3:2-only {approx}15% of Twotinos are projected to survive for 4 Gyr, compared to {approx}27% of Plutinos, based on an extrapolation from our 1-Gyr integrations. We find that Pluto has only a modest effect, causing a {approx}4% decrease in the Plutino population that survives to 4 Gyr. Given current observational estimates, and assuming an initial distribution of particles proportional to the local phase-space volume in the resonance, we conclude that the primordial populations of Plutinos and Twotinos formerly made up more than half the population of the classical and resonant Kuiper Belt. We also conclude that Twotinos were originally nearly as numerous as Plutinos; this is consistent with predictions from early models of smooth giant planet migration and resonance sweeping of the Kuiper Belt and provides a useful constraint for more detailed models.

  17. 20 CFR 220.100 - Evaluation of disability for any regular employment.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... the Social Security Administration and as amended from time to time (20 CFR part 404, subpart P... 20 Employees' Benefits 1 2011-04-01 2011-04-01 false Evaluation of disability for any regular... RAILROAD RETIREMENT ACT DETERMINING DISABILITY Evaluation of Disability § 220.100 Evaluation of...

  18. 20 CFR 220.100 - Evaluation of disability for any regular employment.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... the Social Security Administration and as amended from time to time (20 CFR part 404, subpart P... 20 Employees' Benefits 1 2013-04-01 2012-04-01 true Evaluation of disability for any regular... RAILROAD RETIREMENT ACT DETERMINING DISABILITY Evaluation of Disability § 220.100 Evaluation of...

  19. 20 CFR 220.100 - Evaluation of disability for any regular employment.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... the Social Security Administration and as amended from time to time (20 CFR part 404, subpart P... 20 Employees' Benefits 1 2012-04-01 2012-04-01 false Evaluation of disability for any regular... RAILROAD RETIREMENT ACT DETERMINING DISABILITY Evaluation of Disability § 220.100 Evaluation of...

  20. New Constraints on the Small Kuiper Belt Object Population from High-Resolution Images of Triton

    NASA Astrophysics Data System (ADS)

    McKinnon, W. B.; Schenk, P. M.; Stern, S. A.

    Triton serves as an effective witness plate for Kuiper belt objects due to Triton's proximity to the Kuiper Belt and relatively young surface. Stern and McKinnon (LPSC XXX, abs. #1766, 1999; AJ 119, 945-952, 2000) showed Triton's crater populations to be consistent with a population of sub-km Kuiper belt objects with an approximately b = -3 differential power-law size index, dominance of KBO over Oort cloud impactors, and surface ages under 0.5 Ga. Here we update these findings based on the 10-frame highest resolution image sequence taken by Voyager 2 in 1989, not included in our earlier work. These images suffer degrees of image smear due to uncompensated spacecraft motion, but with careful processing and analysis, meaningful crater counts can be extracted. We focus on regions of abundant and easily discriminated primary craters, such as Cipango Planum (10o N, 35o E), a nearly featureless, rolling volcanic plain. There, craters can be confidently identified down to 1 km diameter, implying Kuiper Belt impactors below 100 m in diameter. The corresponding crater size-frequency index in the 1-to-6 km diameter range is similar to slightly steeper than that for more global counts at larger sizes, but remains consistent with b = -3.

  1. Planet Imager Discovers Young Kuiper Belt

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2015-07-01

    A debris disk just discovered around a nearby star is the closest thing yet seen to a young version of the Kuiper belt. This disk could be a key to better understanding the interactions between debris disks and planets, as well as how our solar system evolved early on in its lifetime. Hunting for an analog The best way to understand how the Kuiper belt — home to Pluto and thousands of other remnants of early icy planet formation in our solar system — developed would be to witness a similar debris disk in an earlier stage of its life. But before now, none of the disks we've discovered have been similar to our own: the rings are typically too large, the central star too massive, or the stars exist in regions very unlike what we think our Sun's birthplace was like. A collaboration led by Thayne Currie (National Astronomical Observatory of Japan) has changed this using the Gemini Planet Imager (GPI), part of a new generation of extreme adaptive-optics systems. The team discovered a debris disk of roughly the same size as the Kuiper belt orbiting the star HD 115600, located in the nearest OB association. The star is only slightly more massive than our Sun, and it lives in a star-forming region similar to the early Sun's environment. HD 115600 is different in one key way, however: it is only 15 million years old. This means that observing it gives us the perfect opportunity to observe how our solar system might have behaved when it was much younger. A promising future GPI's spatially-resolved spectroscopy, combined with measurements of the reflectivity of the disk, have led the team to suspect that the disk might be composed partly of water ice, just as the Kuiper belt is. The disk also shows evidence of having been sculpted by the motions of giant planets orbiting the central star, in much the same way as the outer planets of our solar system may have shaped the Kuiper belt. The observations of HD 115600 are some of the very first to emerge from GPI and the new

  2. New Horizons mission to Pluto and the Kuiper belt

    NASA Astrophysics Data System (ADS)

    McKinnon, W.; Stern, S.; Weaver, H.; Young, L.; Olkin, C.; New Horizons Science Team

    2014-07-01

    two 30--50 kilometer-diameter Kuiper Belt Objects (KBOs) if 1) the spacecraft is in good health, 2) at least one accessible KBO can be located from the Earth or Earth orbit in time, and 3) NASA approves an extended mission. New Horizons previously conducted a successful encounter with Jupiter and the Galilean satellites, has collected and is collecting valuable cruise science data, and became the prototype for NASA's medium-scale, PI-led New Frontiers planetary mission class. The NH flyby of the Pluto system will represent a watershed in the scientific exploration of the Solar System, by exploring a new class of planet in the Solar System --- dwarf planets --- and an accompanying, extensive satellite system. In this review talk we provide a more in-depth overview of the spacecraft, payload, and flyby plans.

  3. Surface composition of Kuiper belt object 1993SC.

    PubMed

    Brown, R H; Cruikshank, D P; Pendleton, Y; Veeder, G J

    1997-05-01

    The 1.42- to 2.40-micrometer spectrum of Kuiper belt object 1993SC was measured at the Keck Observatory in October 1996. It shows a strongly red continuum reflectance and several prominent infrared absorption features. The strongest absorptions in 1993SC's spectrum occur near 1.62, 1.79, 1.95, 2.20, and 2.32 micrometers in wavelength. Features near the same wavelengths in the spectra of Pluto and Neptune's satellite Triton are due to CH4 on their surfaces, suggesting the presence of a simple hydrocarbon ice such as CH4, C2H6, C2H4, or C2H2 on 1993SC. In addition, the red continuum reflectance of 1993SC suggests the presence of more complex hydrocarbons. PMID:9163038

  4. Surface composition of Kuiper belt object 1993SC

    NASA Technical Reports Server (NTRS)

    Brown, R. H.; Cruikshank, D. P.; Pendleton, Y.; Veeder, G. J.

    1997-01-01

    The 1.42- to 2.40-micrometer spectrum of Kuiper belt object 1993SC was measured at the Keck Observatory in October 1996. It shows a strongly red continuum reflectance and several prominent infrared absorption features. The strongest absorptions in 1993SC's spectrum occur near 1.62, 1.79, 1.95, 2.20, and 2.32 micrometers in wavelength. Features near the same wavelengths in the spectra of Pluto and Neptune's satellite Triton are due to CH4 on their surfaces, suggesting the presence of a simple hydrocarbon ice such as CH4, C2H6, C2H4, or C2H2 on 1993SC. In addition, the red continuum reflectance of 1993SC suggests the presence of more complex hydrocarbons.

  5. 20 CFR 402.100 - Exemption six: Clearly unwarranted invasion of personal privacy.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 20 Employees' Benefits 2 2011-04-01 2011-04-01 false Exemption six: Clearly unwarranted invasion... AVAILABILITY OF INFORMATION AND RECORDS TO THE PUBLIC § 402.100 Exemption six: Clearly unwarranted invasion of... mandatory disclosure under Exemption Six. (c) Examples. Some of the information that we frequently...

  6. 20 CFR 402.100 - Exemption six: Clearly unwarranted invasion of personal privacy.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 20 Employees' Benefits 2 2014-04-01 2014-04-01 false Exemption six: Clearly unwarranted invasion... AVAILABILITY OF INFORMATION AND RECORDS TO THE PUBLIC § 402.100 Exemption six: Clearly unwarranted invasion of... mandatory disclosure under Exemption Six. (c) Examples. Some of the information that we frequently...

  7. 20 CFR 402.100 - Exemption six: Clearly unwarranted invasion of personal privacy.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 20 Employees' Benefits 2 2012-04-01 2012-04-01 false Exemption six: Clearly unwarranted invasion... AVAILABILITY OF INFORMATION AND RECORDS TO THE PUBLIC § 402.100 Exemption six: Clearly unwarranted invasion of... mandatory disclosure under Exemption Six. (c) Examples. Some of the information that we frequently...

  8. 20 CFR 402.100 - Exemption six: Clearly unwarranted invasion of personal privacy.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 20 Employees' Benefits 2 2013-04-01 2013-04-01 false Exemption six: Clearly unwarranted invasion... AVAILABILITY OF INFORMATION AND RECORDS TO THE PUBLIC § 402.100 Exemption six: Clearly unwarranted invasion of... mandatory disclosure under Exemption Six. (c) Examples. Some of the information that we frequently...

  9. 20 CFR 402.100 - Exemption six: Clearly unwarranted invasion of personal privacy.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 2 2010-04-01 2010-04-01 false Exemption six: Clearly unwarranted invasion... AVAILABILITY OF INFORMATION AND RECORDS TO THE PUBLIC § 402.100 Exemption six: Clearly unwarranted invasion of... mandatory disclosure under Exemption Six. (c) Examples. Some of the information that we frequently...

  10. 10 CFR 100.20 - Factors to be considered when evaluating sites.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... for Stationary Power Reactor Site Applications on or After January 10, 1997 § 100.20 Factors to be... determining the acceptability of a site for a stationary power reactor: (a) Population density and use... analysis or that may have an impact upon plant design (such as maximum probable wind speed...

  11. 10 CFR 100.20 - Factors to be considered when evaluating sites.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... for Stationary Power Reactor Site Applications on or After January 10, 1997 § 100.20 Factors to be... determining the acceptability of a site for a stationary power reactor: (a) Population density and use... analysis or that may have an impact upon plant design (such as maximum probable wind speed...

  12. 10 CFR 100.20 - Factors to be considered when evaluating sites.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... for Stationary Power Reactor Site Applications on or After January 10, 1997 § 100.20 Factors to be... determining the acceptability of a site for a stationary power reactor: (a) Population density and use... analysis or that may have an impact upon plant design (such as maximum probable wind speed...

  13. 10 CFR 100.20 - Factors to be considered when evaluating sites.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... for Stationary Power Reactor Site Applications on or After January 10, 1997 § 100.20 Factors to be... determining the acceptability of a site for a stationary power reactor: (a) Population density and use... analysis or that may have an impact upon plant design (such as maximum probable wind speed...

  14. 10 CFR 100.20 - Factors to be considered when evaluating sites.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... for Stationary Power Reactor Site Applications on or After January 10, 1997 § 100.20 Factors to be... determining the acceptability of a site for a stationary power reactor: (a) Population density and use... analysis or that may have an impact upon plant design (such as maximum probable wind speed...

  15. 33 CFR 100.20 - Action on application for event assigned to State regulation by Coast Guard-State agreement.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... assigned to State regulation by Coast Guard-State agreement. 100.20 Section 100.20 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY REGATTAS AND MARINE PARADES SAFETY OF LIFE ON NAVIGABLE WATERS § 100.20 Action on application for event assigned to State regulation by Coast...

  16. Phobos from 5,800 Kilometers

    NASA Technical Reports Server (NTRS)

    2008-01-01

    The High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter took two images of the larger of Mars' two moons, Phobos, within 10 minutes of each other on March 23, 2008. This is the second, taken from a distance of about 5,800 kilometers (about 3,600 miles). The illuminated part of Phobos seen in the images is about 21 kilometers (13 miles) across.

    The most prominent feature in the images is the large crater Stickney in the lower right. With a diameter of 9 kilometers (5.6 miles), it is the largest feature on Phobos. A series of troughs and crater chains is obvious on other parts of the moon. Although many appear radial to Stickney in this image, recent studies from the European Space Agency's Mars Express orbiter indicate that they are not related to Stickney. Instead, they may have formed when material ejected from impacts on Mars later collided with Phobos. The lineated textures on the walls of Stickney and other large craters are landslides formed from materials falling into the crater interiors in the weak Phobos gravity (less than one one-thousandth of the gravity on Earth).

    In the full-resolution version of this image, a pixel encompasses 5.8 meters (19 feet), providing a resolution (smallest visible feature) of about 15 meters (about 50 feet). Previous pictures from NASA's Mars Global Surveyor are of slightly higher resolution, at 4 meters (13 feet) per pixel. However, the HiRISE images have higher signal-to-noise, making the new data some of the best ever for Phobos.

    Although the image is displayed here in black and white, data from HiRISE's three color channels were used to give higher signal-to-noise, thereby increasing detail. The image is in the HiRISE catalog as PSP_007769_9015.

    NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Mars Reconnaissance Orbiter for NASA's Science Mission Directorate, Washington. Lockheed Martin

  17. Phobos from 5,800 Kilometers (Color)

    NASA Technical Reports Server (NTRS)

    2008-01-01

    The High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter took two images of the larger of Mars' two moons, Phobos, within 10 minutes of each other on March 23, 2008. This is the second, taken from a distance of about 5,800 kilometers (about 3,600 miles). It is presented in color by combining data from the camera's blue-green, red, and near-infrared channels.

    The illuminated part of Phobos seen in the images is about 21 kilometers (13 miles) across. The most prominent feature in the images is the large crater Stickney in the lower right. With a diameter of 9 kilometers (5.6 miles), it is the largest feature on Phobos.

    The color data accentuate details not apparent in black-and-white images. For example, materials near the rim of Stickney appear bluer than the rest of Phobos. Based on analogy with materials on our own moon, this could mean this surface is fresher, and therefore younger, than other parts of Phobos.

    A series of troughs and crater chains is obvious on other parts of the moon. Although many appear radial to Stickney in this image, recent studies from the European Space Agency's Mars Express orbiter indicate that they are not related to Stickney. Instead, they may have formed when material ejected from impacts on Mars later collided with Phobos. The lineated textures on the walls of Stickney and other large craters are landslides formed from materials falling into the crater interiors in the weak Phobos gravity (less than one one-thousandth of the gravity on Earth).

    In the full-resolution version of this image, a pixel encompasses 5.8 meters (19 feet), providing a resolution (smallest visible feature) of about 15 meters (about 50 feet). Previous pictures from NASA's Mars Global Surveyor are of slightly higher resolution, at 4 meters (13 feet) per pixel. However, the HiRISE images have higher signal-to-noise, making the new data some of the best ever for Phobos. This image is in the Hi

  18. Kuiper belt structure around nearby super-Earth host stars

    NASA Astrophysics Data System (ADS)

    Kennedy, Grant M.; Matrà, Luca; Marmier, Maxime; Greaves, Jane S.; Wyatt, Mark C.; Bryden, Geoffrey; Holland, Wayne; Lovis, Christophe; Matthews, Brenda C.; Pepe, Francesco; Sibthorpe, Bruce; Udry, Stéphane

    2015-05-01

    We present new observations of the Kuiper belt analogues around HD 38858 and HD 20794, hosts of super-Earth mass planets within 1 au. As two of the four nearby G-type stars (with HD 69830 and 61 Vir) that form the basis of a possible correlation between low-mass planets and debris disc brightness, these systems are of particular interest. The disc around HD 38858 is well resolved with Herschel and we constrain the disc geometry and radial structure. We also present a probable James Clerk Maxwell Telescope sub-mm continuum detection of the disc and a CO J = 2-1 upper limit. The disc around HD 20794 is much fainter and appears marginally resolved with Herschel, and is constrained to be less extended than the discs around 61 Vir and HD 38858. We also set limits on the radial location of hot dust recently detected around HD 20794 with near-IR interferometry. We present High Accuracy Radial velocity Planet Searcher upper limits on unseen planets in these four systems, ruling out additional super-Earths within a few au, and Saturn-mass planets within 10 au. We consider the disc structure in the three systems with Kuiper belt analogues (HD 69830 has only a warm dust detection), concluding that 61 Vir and HD 38858 have greater radial disc extent than HD 20794. We speculate that the greater width is related to the greater minimum planet masses (10-20 M⊕ versus 3-5 M⊕), arising from an eccentric planetesimal population analogous to the Solar system's scattered disc. We discuss alternative scenarios and possible means to distinguish among them.

  19. Stress dependent magnetostriction in highly magnetostrictive Fe100-xGax, 20

    NASA Astrophysics Data System (ADS)

    Clark, A. E.; Yoo, J.-H.; Cullen, J. R.; Wun-Fogle, M.; Petculescu, G.; Flatau, A.

    2009-04-01

    Saturation magnetostriction measurements along the [100] axis of Fe100-xGax single crystal rods (˜25×6mm diameter) were observed to have a linear dependence on [100] applied compressive stresses for 20100] magnetostriction. For x =20.9 and 29.5, the stress T dependencies of the saturation magnetostrictions were found to be 0.136×10-6TMPa-1 and 0.281×10-6TMPa-1, respectively. Values of the third order elastic constants, c3's, calculated from these values agree both in sign and magnitude with those obtained from stress dependent measurements of Young's moduli and Poisson's ratios. In sum, we conclude that the Fe100-xGax magnetostriction for 0

  20. Consequences of planetary migration: Kuiper belt dynamics and atmospheric escape from hot Jupiters

    NASA Astrophysics Data System (ADS)

    Murray-Clay, Ruth Ann

    The current resonance structure of the Kuiper belt suggests that during the late stages of planet formation, Neptune migrated outward as it scattered residual planetesimal debris. Extrasolar planetary systems also show evidence for planetary migration. Approximately 1/5 of the extrasolar planets discovered to date are "hot Jupiters," which likely exchanged angular momentum with gas disks, migrating large distances inward to reach their current semi-major axes of ~0.05 AU. In this thesis, I discuss three consequences of planetary migration. (1) During its migration, Neptune captured Kuiper belt objects (KBOs) into mean motion resonances. The current spatial distribution of KBOs in a particular resonance, the 2:1, acts as a celestial speedometer--fast planetary migration generates a larger population of 2:1 resonant KBOs trailing rather than leading Neptune on the sky. We provide an explanation of this phenomenon for the first time. Central to our understanding is how planetary migration shifts the equilibrium points of the superposed direct and indirect potentials felt by a KBO. The currently observed distribution of 2:1 KBOs excludes total migration times < 20 Myr with >99.65% confidence and is statistically consistent with the even population generated by slow migration. However, these observations are beset by systematic uncertainties. Observations with new telescopes such as PanSTARRS or LSST will tell us how quickly Neptune could have migrated. (2) Neptune's migration, powered by scattering planetesimal debris, was stochastic ("noisy"). Extreme stochasticity defeats resonance capture. We construct a theory analogous to Brownian motion for how a planet's orbital semi-major axis fluctuates in response to random planetesimal scatterings. The degree of stochasticity in Neptune's migration depends both on the sizes of the planetesimals driving migration and on their orbital elements and cannot currently be computed using N-body simulations. We find that capture of

  1. 20 CFR 664.620 - Do the core indicators described in 20 CFR 666.100(a)(3) apply to participation in summer...

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... indicators described in 20 CFR 666.100(a)(3) apply to participation in summer employment activities? Yes, the... 20 Employees' Benefits 4 2013-04-01 2013-04-01 false Do the core indicators described in 20 CFR 666.100(a)(3) apply to participation in summer employment activities? 664.620 Section...

  2. 20 CFR 664.620 - Do the core indicators described in 20 CFR 666.100(a)(3) apply to participation in summer...

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... indicators described in 20 CFR 666.100(a)(3) apply to participation in summer employment activities? Yes, the... 20 Employees' Benefits 4 2014-04-01 2014-04-01 false Do the core indicators described in 20 CFR 666.100(a)(3) apply to participation in summer employment activities? 664.620 Section...

  3. 20 CFR 664.620 - Do the core indicators described in 20 CFR 666.100(a)(3) apply to participation in summer...

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... described in 20 CFR 666.100(a)(3) apply to participation in summer employment activities? Yes, the summer... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false Do the core indicators described in 20 CFR 666.100(a)(3) apply to participation in summer employment activities? 664.620 Section...

  4. 20 CFR 664.620 - Do the core indicators described in 20 CFR 666.100(a)(3) apply to participation in summer...

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... indicators described in 20 CFR 666.100(a)(3) apply to participation in summer employment activities? Yes, the... 20 Employees' Benefits 4 2012-04-01 2012-04-01 false Do the core indicators described in 20 CFR 666.100(a)(3) apply to participation in summer employment activities? 664.620 Section...

  5. Kuiper Belt Objects Along the Pluto-Express Path

    NASA Technical Reports Server (NTRS)

    Jewitt, David (Principal Investigator)

    1997-01-01

    The science objective of this work is to identify objects in the Kuiper Belt which will, in the 5 years following Pluto encounter, be close to the flight path of NASA's Pluto Express. Our hope is that we will find a Kuiper Belt object or objects close enough that a spacecraft flyby will be possible. If we find a suitable object, the science yield of Pluto Express will be substantially enhanced. The density of objects in the Kuiper Belt is such that we are reasonably likely to find an object close enough to the flight path that on-board gas thrusters can effect a close encounter.

  6. The small numbers of large Kuiper Belt objects

    SciTech Connect

    Schwamb, Megan E.; Brown, Michael E.; Fraser, Wesley C.

    2014-01-01

    We explore the brightness distribution of the largest and brightest (m(R) < 22) Kuiper Belt Objects (KBOs). We construct a luminosity function of the dynamically excited or hot Kuiper Belt (orbits with inclinations >5°) from the very brightest to m(R) = 23. We find for m(R) ≲ 23, a single slope appears to describe the luminosity function. We estimate that ∼12 KBOs brighter than m(R) ∼ 19.5 are present in the Kuiper Belt today. With nine bodies already discovered this suggests that the inventory of bright KBOs is nearly complete.

  7. Into the Kuiper Belt: New Horizons Post-Pluto

    NASA Astrophysics Data System (ADS)

    Harrison Parker, Alex; Spencer, John; Benecchi, Susan; Binzel, Richard; Borncamp, David; Buie, Marc; Fuentes, Cesar; Gwyn, Stephen; Kavelaars, JJ; Noll, Keith; Petit, Jean-Marc; Porter, Simon; Showalter, Mark; Stern, S. Alan; Sterner, Ray; Tholen, David; Verbiscer, Anne; Weaver, Hal; Zangari, Amanda

    2015-11-01

    New Horizons is now beyond Pluto and flying deeper into the Kuiper Belt. In the summer of 2014, a Hubble Space Telescope Large Program identified two candidate Cold Classical Kuiper Belt Objects (KBOs) that were within reach of New Horizons' remaining fuel budget. Here we present the selection of the Kuiper Belt flyby target for New Horizons' post-Pluto mission, our state of knowledge regarding this target and the potential 2019 flyby, the status of New Horizons' targeting maneuver, and prospects for near-future long-range observations of other KBOs.

  8. Molecular spectroscopy from the Kuiper Airborne Observatory

    NASA Technical Reports Server (NTRS)

    Beckwith, S.

    1985-01-01

    Interstellar and circumstellar molecules are investigated through medium-resolution infrared spectrosocpy of the vibration-rotation and pure rotational transitions. A primary goal was the construction and improvement of instrumentation for the near and middle infrared regions, wavelengths between 2 and 10 microns. The main instrument was a cooled grating spectrometer with an interchangeable detector focal plane which could be used on the Kuiper Airborne Observatory (KAO) for airborne observations, and also at ground-based facilities. Interstellar shock waves were investigated by H2 emission from the Orion Nebula, W51, and the proto-planetary nebulae CRL 2688 and CRL 618. The observations determined the physical conditions in shocked molecular gas near these objects. From these it was possible to characterize the energetic history of mass loss from both pre- and post-main sequence stars in the regions.

  9. Spectroscopy of Kuiper Belt Objects and Centaurs

    NASA Technical Reports Server (NTRS)

    Cruikshank, Dale P.; Brown, Robert H.; Pendleton, Y. J.; Veeder, Glenn J.

    1998-01-01

    Recent near-infrared spectroscopy of Kuiper Belt objects and Centaurs indicates considerable spectral diversity among them. Some have entirely bland spectra with no discernible spectral features (e.g., Chiron), while 5145 Pholus has a very active spectrum with absorption bands of H2O, CH3OH, and probably the mineral olivine present. In addition, the strong red color of Pholus indicates the presence of organic solids. Among the KBOs, 1993 SC has an active spectrum with the probably presence of hydrocarbons and possibly the ices of H2O and N2. The diversity among these spectra and the implications that such diversity has for models of the formation of the formation of the planets will be discussed.

  10. Update on the Square Kilometer Array

    NASA Astrophysics Data System (ADS)

    Tarter, Jill

    2002-01-01

    In August 2000 representatives of 24 groups in 10 countries signed a memorandum of understanding to continue cooperative technology development on five different antenna concepts intended to enable the cost-effective construction of a radio telescope array with one million square meters of collecting area; the Square Kilometer Array (SKA). The goal of this MOA is to find innovative ways of solving the many technical challenges posed by this mammouth array, and to drive down the costs so that this can realistically be afforded as a groundbased, international project for radio astronomy. The science drivers for this large instrument are diverse and very exciting; SETI being one of them. However, this means that the technical specifications are extremely challenging. There is historical reason to believe that these goals can be met. For the past six decades, the capability of radio astronomy facilities has been improving exponentially, and the SKA represents the logical extrapolation of this trend. In 2005 a selection of one or more of the current antenna concepts will be made, along with the choice of a suitable site and configuration for the array. Final detailed designs and prototyping will follow. Construction could start by the end of this decade. The SKA will permit SETI observations over a wider range of frequencies, and will offer a sensitivity that is two orders of magnitude better than current arrays. This improved performance justifies all the effort needed to overcome the technological, political, and bureaucratic challenges inherent in this international mega-science project.

  11. An Access To The Unknown Kuiper Belt

    NASA Astrophysics Data System (ADS)

    Roques, Francoise

    2007-10-01

    The size distribution in the Kuiper Belt is unknown for faint objects. Current differential size distribution estimates give a slope of 4.5+- 0.2 for large end until mR=26 (Petit et al., 2007) but the population of fainter objects (small and far) is unknown. Observations with the HST (Bernstein et al., 2004) with a limiting magnitude de 28.5 could indicate a very shallow size distribution for small KBOs. The estimated slope would much smaller than expected from collisional equilibrium. It would also be smaller than the estimation of small KBOs numbers deduced from analyse of Triton cratering (Stern and McKinnon, 2000). It will be very difficult to improve these contradictory results from direct observations. The next advance could come from occultations of background targets. Three independant observations have announced occultations detections of KBOs. Observations of the bright X target Scorpius X1 by the satellite RXTE reveals 12 events compatible with KBOs occultations (Chang et al. 2007). Several occultations detections have been announced by Georgevits et al. (2006). The conditions of these two observations do not allow to measure the distance of the occulting objects. Three events were detected by Roques et al, 2006 but none is in the known Kuiper region. Occultation is a non reproductible phenomenon. Reliable results can only be obtained from simultaneous detection from two nearby telescope, or by signature of diffraction (expected with a very small target star and good temporal definition of the light curve) or by statistical signature of a large events data set (correlation with direction of observation or with the ecliptic latitude). Moreover, it is very difficult to compare results from different instruments in differents configurations. Results from three research campaigns with Ultracam are presented with an attempt of comparison with other results and some remarks about instruments best adapted for occultations works.

  12. The Relative Sizes of Kuiper Belt Binaries

    NASA Astrophysics Data System (ADS)

    Noll, Keith S.; Grundy, W. M.; Levison, H. F.; Stephens, D. C.

    2006-09-01

    Nearly 40 binary and multiple systems are now known in the Kuiper Belt. Most of these consist of similar-sized components; for some it is problematic to define a primary and a secondary. Systems with faint companions do exist. In the Pluto system, the most extreme example known, the two newly identified satellites are approximately 9 magnitudes fainter than Pluto. Observational bias favors the detection of bright secondaries, especially in low or modest S/N observations, a common occurrence in the observation of transneptunian objects. Because of this bias, it has not been clear whether the apparent preference for similar-sized components in binaries is real or an observational artifact. In the last year we have made very deep observations of 61 Centaurs and TNOs using the Hubble Space Telescope High Resolution Camera. These observations have 3-sigma detection limits of visual magnitude 27.5 or fainter. This is the first large data set capable of assessing the relative frequency of symmetric (similar brightness) and asymmetric (large brightness differences) binaries. Our data show a clear and significant preference for companions that have a 1 magnitude or smaller difference compared to the primary. This result confirms the qualitative prediction of the chaos-assisted model for binary formation (Astakhov et al. 2005, MRAS 360, 401) and supports the contention that most of the bound systems in the Kuiper Belt formed via mutual capture. Asymmetric systems may, in contrast, be the result of collisional formation as is postulated for the Pluto system (Stern et al. 2006, Nature, 439, 946). Based on observations made with the NASA/ESA Hubble Space Telescope program #10514. Support for program #10514 was provided by NASA through a grant from the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555.

  13. INCLINATION MIXING IN THE CLASSICAL KUIPER BELT

    SciTech Connect

    Volk, Kathryn; Malhotra, Renu

    2011-07-20

    We investigate the long-term evolution of the inclinations of the known classical and resonant Kuiper Belt objects (KBOs). This is partially motivated by the observed bimodal inclination distribution and by the putative physical differences between the low- and high-inclination populations. We find that some classical KBOs undergo large changes in inclination over gigayear timescales, which means that a current member of the low-inclination population may have been in the high-inclination population in the past, and vice versa. The dynamical mechanisms responsible for the time variability of inclinations are predominantly distant encounters with Neptune and chaotic diffusion near the boundaries of mean motion resonances. We reassess the correlations between inclination and physical properties including inclination time variability. We find that the size-inclination and color-inclination correlations are less statistically significant than previously reported (mostly due to the increased size of the data set since previous works with some contribution from inclination variability). The time variability of inclinations does not change the previous finding that binary classical KBOs have lower inclinations than non-binary objects. Our study of resonant objects in the classical Kuiper Belt region includes objects in the 3:2, 7:4, 2:1, and eight higher-order mean motion resonances. We find that these objects (some of which were previously classified as non-resonant) undergo larger changes in inclination compared to the non-resonant population, indicating that their current inclinations are not generally representative of their original inclinations. They are also less stable on gigayear timescales.

  14. Discovery of the candidate Kuiper belt object 1992 QB1

    NASA Technical Reports Server (NTRS)

    Jewitt, David; Luu, Jane

    1993-01-01

    The discovery of a new faint object in the outer solar system, 1992 QB1, moving beyond the orbit of Neptune is reported. It is suggested that the 1992 QB1 may represent the first detection of a member of the Kuiper belt (Edgworth, 1949; Kuiper, 1951), the hypothesized population of objects beyond Neptune and a possible source of the short-period comets, as suggested by Whipple (1964), Fernandez (1980), and Duncan et al. (1988).

  15. Kuiper Belt Objects Along the Pluto Express Path

    NASA Technical Reports Server (NTRS)

    Jewitt, David

    1999-01-01

    The objective of this proposal was to mount a ground-based search for Kuiper Belt objects near the trajectory of the NASA Pluto Express spacecraft. The high density of Kuiper Belt objects established from work on Mauna Kea makes it probable that one or more bodies can be visited by Pluto Express after its encounter with Pluto. The work was funded during its first year through NASA HQ. The second year was funded through Goddard. The third year was never funded.

  16. Microchannel plate pinhole camera for 20 to 100 keV x-ray imaging

    SciTech Connect

    Wang, C.L.; Leipelt, G.R.; Nilson, D.G.

    1984-10-03

    We present the design and construction of a sensitive pinhole camera for imaging suprathermal x-rays. Our device is a pinhole camera consisting of four filtered pinholes and microchannel plate electron multiplier for x-ray detection and signal amplification. We report successful imaging of 20, 45, 70, and 100 keV x-ray emissions from the fusion targets at our Novette laser facility. Such imaging reveals features of the transport of hot electrons and provides views deep inside the target.

  17. Temperature dependence and origin of InP(100) reflectance anisotropy down to 20 K

    NASA Astrophysics Data System (ADS)

    Visbeck, S.; Hannappel, T.; Zorn, M.; Zettler, J.-T.; Willig, F.

    2001-06-01

    InP(100) surfaces were investigated by reflectance anisotropy spectroscopy (RAS) in the temperature range between 20 and 840 K. Surfaces were prepared via metal-organic chemical vapor deposition (MOCVD) resulting in P-terminated (2×1)-like and In-terminated (2×4) reconstructions. Additionally, intermediate states of different phosphorus coverage were prepared. RA spectra were recorded both inside the MOCVD reactor and in an ultrahigh vacuum chamber. At low temperatures, features in the RA spectra sharpened significantly due to the reduced lattice vibrations and electron-phonon interactions. The temperature-dependent energy shift of specific RAS features was determined between 20 and 840 K, and fitted with a model containing the Bose-Einstein occupation factor for phonons. The respective fitting parameters were compared to those of the InP bulk critical-point transitions nearby. Careful data analysis provided evidence for surface transitions and surface modified bulk transitions in the RA spectra.

  18. COLORS OF INNER DISK CLASSICAL KUIPER BELT OBJECTS

    SciTech Connect

    Romanishin, W.; Tegler, S. C.; Consolmagno, G. J. E-mail: Stephen.Tegler@nau.ed

    2010-07-15

    We present new optical broadband colors, obtained with the Keck 1 and Vatican Advanced Technology telescopes, for six objects in the inner classical Kuiper Belt. Objects in the inner classical Kuiper Belt are of interest as they may represent the surviving members of the primordial Kuiper Belt that formed interior to the current position of the 3:2 resonance with Neptune, the current position of the plutinos, or, alternatively, they may be objects formed at a different heliocentric distance that were then moved to their present locations. The six new colors, combined with four previously published, show that the ten inner belt objects with known colors form a neutral clump and a reddish clump in B-R color. Nonparametric statistical tests show no significant difference between the B-R color distribution of the inner disk objects compared to the color distributions of Centaurs, plutinos, or scattered disk objects. However, the B-R color distribution of the inner classical Kuiper Belt Objects does differ significantly from the distribution of colors in the cold (low inclination) main classical Kuiper Belt. The cold main classical objects are predominately red, while the inner classical belt objects are a mixture of neutral and red. The color difference may reveal the existence of a gradient in the composition and/or surface processing history in the primordial Kuiper Belt, or indicate that the inner disk objects are not dynamically analogous to the cold main classical belt objects.

  19. Kilometer-scale Kaiser effect identified in Krafla volcano, Iceland

    NASA Astrophysics Data System (ADS)

    Heimisson, Elías Rafn; Einarsson, Páll; Sigmundsson, Freysteinn; Brandsdóttir, Bryndís.

    2015-10-01

    The Krafla rifting episode in 1975-1984, consisted of around 20 inflation-deflation events within the Krafla caldera, where magma accumulated during inflation periods and was intruded into the transecting fissure swarm during brief periods of deflation. We reanalyze geodetic and seismic data from the rifting episode and perform a time-dependent inversion of a leveling time series for a spherical point source in an elastic half-space. Using the volume change as a proxy for stress shows that during inflation periods the seismicity rate remains low until the maximum inflation of previous cycles is exceeded thus exhibiting the Kaiser effect. Our observations demonstrate that this phenomenon, commonly observed in small-scale experiments, is also produced in kilometer-scale volcanic deformation. This behavior sheds new light on the relationship between deformation and seismicity of a deforming volcano. As a consequence of the Kaiser effect, a volcano may inflate rapidly without significant changes in seismicity rate.

  20. Design study for a superconducting proton linac from 20 to 100 MeV

    SciTech Connect

    Wangler, T.P.; Garnett, R.; Krawczyk, F.; Billen, J.; Bultman, N.; Christensen, K.; Fox, W.; Wood, R.

    1993-07-01

    Advances in superconducting radiofrequency technology during the past 15 years have made possible the large-scale application of superconducting niobium accelerators. So far this development has been restricted to rather low-current electron and heavy-ion accelerators. In addition to the power savings, the improved capability of superconducting cavities to provide acceleration of high currents with low beam losses, which follows from the ability to use larger beam apertures without a large economic penalty from increased rf losses, could make superconducting proton linacs very attractive for high-intensity applications, where activation of the accelerator is a major concern. During the past year, at Los Alamos, the authors have been looking at a possible upgrade to the 800-MeV LAMPF proton accelerator, to provide higher intensity injection into a new storage ring for a new high-intensity pulsed neutron source. As part of this upgrade to the LAMPF accelerator, the entire linac below 100 MeV would be rebuilt to provide improved beam quality, improved reliability, and to include funneling at 20 MeV for higher beam currents. Both a room-temperature and a superconducting option are being considered for the section from 20 to 100 MeV. At present, this section is a 201.25 MHz room-temperature copper drift-tube linac (DTL). For this new upgrade scenario the frequency from 20 to 100 MeV was fixed at 805 MHz. The new duty factor is assumed to be 7.2%, and the authors show some results at two currents, 30 mA and 150 mA, that span the range of interest. Their superconducting linac concept consists of individual multicell cavities, each driven by a klystrode. Focusing would be provided by superconducting quadrupole lenses between cavities. In the remainder of the paper they describe their study to evaluate the potential of a superconducting proton linac section for this application, and address some of the many design choices.

  1. Chiron and the Centaurs: Escapees from the Kuiper Belt

    NASA Technical Reports Server (NTRS)

    Stern, Alan; Campins, Humberto

    1996-01-01

    The outer Solar System has long appeared to be a largely empty place, inhabited only by the four giant planets, Pluto and a transient population of comets. In 1977 however, a faint and enigmatic object - 2060 Chiron - was discovered moving on a moderately inclined, strongly chaotic 51-year orbit which takes it from just inside Saturn's orbit out almost as far as that of Uranus. It was not initially clear from where Chiron originated. these objects become temporarily trapped on Centaur-like orbits Following Chiron's discovery, almost 15 years elapsed before other similar objects were discovered; five more have now been identified. Based on the detection statistics implied by these discoveries, it has become clear that these objects belong to a significant population of several hundred (or possibly several thousand) large icy bodies moving on relatively short-lived orbits between the giant planets. This new class of objects, known collectively as the Centaurs, are intermediate in diameter between typical comets (1-20 km) and small icy planets such as Pluto (approx. 2,300 km) and Triton (approx. 2,700 km). Although the Centaurs are interesting in their own right, they have taken on added significance following the recognition that they most probably originated in the ancient reservoir of comets and larger objects located beyond the orbit of Neptune known as the Kuiper belt.

  2. 20 CFR 664.620 - Do the core indicators described in 20 CFR 666.100(a)(3) apply to participation in summer...

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 20 Employees' Benefits 3 2011-04-01 2011-04-01 false Do the core indicators described in 20 CFR... described in 20 CFR 666.100(a)(3) apply to participation in summer employment activities? Yes, the summer... Employees' Benefits EMPLOYMENT AND TRAINING ADMINISTRATION, DEPARTMENT OF LABOR YOUTH ACTIVITIES UNDER...

  3. The Warped Plane of the Classical Kuiper Belt

    NASA Astrophysics Data System (ADS)

    Chiang, Eugene; Choi, Hyomin

    2008-07-01

    By numerically integrating the orbits of the giant planets and of test particles over a period of four billion years, we follow the evolution of the location of the midplane of the Kuiper belt. The Classical Kuiper belt conforms to a warped sheet that precesses with a 1.9 Myr period. The present-day location of the Kuiper belt plane can be computed using linear secular perturbation theory: the local normal to the plane is given by the theory's forced inclination vector, which is specific to every semimajor axis. The Kuiper belt plane does not coincide with the invariable plane, but deviates from it by up to a few degrees in stable zones. For example, at a semimajor axis of 38 AU, the local Kuiper belt plane has an inclination of 1.9 degrees and a longitude of ascending node of 149.9 degrees when referred to the mean ecliptic and equinox of J2000. At a semimajor axis of 43 AU, the local plane has an inclination of 1.9 degrees and a nodal longitude of 78.3 degrees. Only at infinite semimajor axis does the Kuiper belt plane merge with the invariable plane, whose inclination is 1.6 degrees and nodal longitude is 107.7 degrees. A Classical Kuiper belt object keeps its inclination relative to the Kuiper belt plane nearly constant, even while the plane departs from the trajectory predicted by linear theory. The constancy of relative inclination reflects the undamped amplitude of free oscillation; that is, the homogeneous solution to the forced harmonic oscillator equation retains constant amplitude, even while the inhomogeneous solution cannot be written down accurately because the planetary forcing terms are chaotic. Current observations of Classical Kuiper belt objects are consistent with the plane being warped by the giant planets alone, but the sample size will need to increase by a few times before confirmation exceeds 3σ in confidence. In principle, differences between the theoretically expected plane and the observed plane could be used to infer as yet unseen

  4. USING KUIPER BELT BINARIES TO CONSTRAIN NEPTUNE'S MIGRATION HISTORY

    SciTech Connect

    Murray-Clay, Ruth A.; Schlichting, Hilke E.

    2011-04-01

    Approximately 10%-20% of all Kuiper Belt objects (KBOs) occupy mean-motion resonances with Neptune. This dynamical configuration likely resulted from resonance capture as Neptune migrated outward during the late stages of planet formation. The details of Neptune's planetesimal-driven migration, including its radial extent and the concurrent eccentricity evolution of the planet, are the subject of considerable debate. Two qualitatively different proposals for resonance capture have been proposed-migration-induced capture driven by smooth outward evolution of Neptune's orbit and chaotic capture driven by damping of the planet's eccentricity near its current semi-major axis. We demonstrate that the distribution of comparable-mass, wide-separation binaries occupying resonant orbits can differentiate between these two scenarios. If migration-induced capture occurred, this fraction records information about the formation locations of different populations of KBOs. Chaotic capture, in contrast, randomizes the orbits of bodies as they are placed in resonance. In particular, if KBO binaries are formed by dynamical capture in a protoplanetary disk with a surface mass density typical of observed extrasolar disks, then migration-induced capture produces the following signatures. The 2:1 resonance should contain a dynamically cold component, with inclinations less than 5{sup 0}-10{sup 0}, having a binary fraction comparable to that among cold classical KBOs. If the 3:2 resonance also hosts a cold component, its binary fraction should be 20%-30% lower than in the cold classical belt. Among cold 2:1 (and if present 3:2) KBOs, objects with eccentricities e < 0.2 should have a binary fraction {approx}20% larger than those with e>0.2. Other binary formation scenarios and disk surface density profiles can generate analogous signatures but produce quantitatively different results. Searches for cold components in the binary fractions of resonant KBOs are currently practical. The

  5. High-Latitude Ionospheric Structuring at Kilometer Scales

    NASA Astrophysics Data System (ADS)

    Bust, G. S.; Datta-Barua, S.; Su, Y.; Deshpande, K.; Hampton, D.

    2014-12-01

    Ionospheric observations in the polar and auroral zones have been made regularly with radar chains and optical imaging at larger spatio-temporal cadence. However, the observation of kilometer scale variations at sub-second cadence has not been practically realizable until recently. Quantifying the irregularities at these sizes and scales is necessary for an understanding of the dynamics leading to fine scale phenomena in the high latitude environment. We present measurements of kilometer-scale plasma variations made at the northern auroral zone using an array of specialized Global Positioning System (GPS) receivers. These 6 CASES receivers (plus 1 from ASTRA, LLC) are sited at the Poker Flat Research Range, Alaska, and have been collecting data since late 2013. The array monitors for ionospheric scintillations, fluctuations in phase and amplitude of the GPS L-band signals received due to ionospheric variations. The array spans 2 km east-west and about 1 km north-south, with a variety of intermediate baseline lengths down to about 200 m. In addition to measuring amplitude and phase scintillation with the S4 and sigma_phi indices at 100-s cadence, these receivers also record 100 Hz raw power and phase measurements from GPS baseband signal processing. These low-rate data are publicly available for download through a web portal at http://apollo.tbc.iit.edu/~spaceweather/ with high rate available upon request. A detailed case study is presented from the December 8, 2013, 0300-0400 UT time period. During this period several interesting scintillation periods were observed. We use array cross-correlation processing methods to first estimate direct ground parameters of the array including a) estimate the 2D drift velocity on the ground; b) estimate a de-correlation (or turbulent) speed; and c) parameters of correlation elliptical coordinates (axial ratio and tilt angle). We then use these results and cross-correlation measurements to derive the ground 2D spatial spectrum of

  6. Photographer : JPL Range : 1 million kilometers Voyager 2 completed a dramatic 10 hour time lapse

    NASA Technical Reports Server (NTRS)

    1979-01-01

    Photographer : JPL Range : 1 million kilometers Voyager 2 completed a dramatic 10 hour time lapse photo sequence to monitor the active volcanos on Jupiter's moon Io following the spacecraft's closest approach to Jupiter. This picture is one of about 200 images that will be used to generate a time lapse motion picture to illustrate Io's volcanic activity. On the bright limb, two of the plumes (P-5 & P-6) discovered in March by Voyager 1 are again visible. The plumes are spewing materials to a height of about 100 kilometers.

  7. In-situ monitoring of InP(100) and GaP(100) interfaces and characterization with RDS at 20 K

    NASA Astrophysics Data System (ADS)

    Hannappel, T.; Töben, L.; Möller, K.; Willig, F.

    2001-11-01

    MOVPE-preparation of highly ordered InP(100) and GaP(100) surfaces was monitored with in-situ reflectance difference spectroscopy (RDS). Specific ordered P-terminated and ordered cation-terminated surface reconstructions were identified with specific structured RD spectra with the highest peaks. After contamination-free transfer of the samples to UHV, RDS measurements were performed also at 20 K. The experimental RD spectrum for the In-terminated, (2×4) reconstructed InP(100) surface shows a remarkable similarity to a recently published theoretical spectrum, whereas there is only moderate similarity between the experimental RD spectrum for the (2×4) reconstructed Ga-terminated GaP(100) surface and a recently proposed theoretical spectrum.

  8. K-(alpha) Radiography at 20-100 keV Using Short-Pulse Lasers

    SciTech Connect

    Park, H S; Chambers, D; Clarke, R; Eagleton, R; Giraldez, E; Goldsack, T; Heathcote, R; Izumi, N; Key, M; King, J; Koch, J; Landen, O L; Mackinnon, A; Nikroo, A; Patel, P; Pasley, J; Remington, B; Robey, H; Snavely, R; Steinman, D; Stephenson, R; Stoeckl, C; Storm, M; Tabak, M; Theobald, W; Town, R J

    2005-08-29

    X-ray radiography is an important tool for diagnosing and imaging planar and convergent hydrodynamics phenomena for laser experiments. Until now, hydrodynamics experiments at Omega and NIF utilize E{sub x-ray} < 9 keV backlighter x-rays emitted by thermal plasmas. However, future experiments will need to diagnose larger and denser targets and will require x-ray probes of energies from 20-100 keV and possibly up to 1 MeV. Hard K-{alpha} x-ray photons can be created through high-energy electron interactions in the target material after irradiation by petawatt-class high-intensity-short-pulse lasers with > 10{sup 17} W/cm{sup 2}. We have performed several experiments on the JanUSP, and the Vulcan 100TW, and Vulcan Petawatt lasers to understand K-{alpha} sources and to test radiography concepts. 1-D radiography using an edge-on foil and 2-D radiography using buried wires and cone-fiber targets were tested. We find that 1-D thin edge-on foils can have imaging resolution better than 10 {micro}m. Micro volume targets produce bright sources with measured conversion efficiency from laser energy to x-ray photons of {approx} 1 x 10{sup -5}. This level of conversion may not be enough for 2-D point projection radiography. A comparison of our experimental measurements of small volume sources with the LSP/PIC simulation show similar K-{alpha} creation profiles but discrepancy in absolute yields.

  9. Neptune's Eccentricity and the Nature of the Kuiper Belt

    NASA Technical Reports Server (NTRS)

    Ward, William R.; Hahn, Joseph M.

    1998-01-01

    The small eccentricity of Neptune may be a direct consequence of apsidal wave interaction with the trans-Neptune population of debris called the Kuiper belt. The Kuiper belt is subject to resonant perturbations from Neptune, so that the transport of angular momentum by density waves can result in orbital evolution of Neptune as well as changes in the structure of the Kuiper belt. In particular, for a belt eroded out to the vicinity of Neptune's 2:1 resonance at about 48 astronomical units, Neptune's eccentricity can damp to its current value over the age of the solar system if the belt contains slightly more than an earth mass of material out to about 75 astronomical units.

  10. Neptune's eccentricity and the nature of the kuiper belt

    PubMed

    Ward; Hahn

    1998-06-26

    The small eccentricity of Neptune may be a direct consequence of apsidal wave interaction with the trans-Neptune population of debris called the Kuiper belt. The Kuiper belt is subject to resonant perturbations from Neptune, so that the transport of angular momentum by density waves can result in orbital evolution of Neptune as well as changes in the structure of the Kuiper belt. In particular, for a belt eroded out to the vicinity of Neptune's 2:1 resonance at about 48 astronomical units, Neptune's eccentricity can damp to its current value over the age of the solar system if the belt contains slightly more than an earth mass of material out to about 75 astronomical units. PMID:9641913

  11. FORMATION OF KUIPER BELT BINARIES BY GRAVITATIONAL COLLAPSE

    SciTech Connect

    Nesvorny, David; Youdin, Andrew N.; Richardson, Derek C.

    2010-09-15

    A large fraction of {approx}100 km class low-inclination objects in the classical Kuiper Belt (KB) are binaries with comparable masses and a wide separation of components. A favored model for their formation is that they were captured during the coagulation growth of bodies in the early KB. However, recent studies have suggested that large, {approx}>100 km objects can rapidly form in the protoplanetary disks when swarms of locally concentrated solids collapse under their own gravity. Here, we examine the possibility that KB binaries formed during gravitational collapse when the excess of angular momentum prevented the agglomeration of available mass into a solitary object. We find that this new mechanism provides a robust path toward the formation of KB binaries with observed properties, and can explain wide systems such as 2001 QW{sub 322} and multiples such as (47171) 1999 TC{sub 36}. Notably, the gravitational collapse is capable of producing {approx}100% binary fraction for a wide range of the swarm's initial angular momentum values. The binary components have similar masses ({approx}80% have a secondary-over-primary radius ratio >0.7) and their separation ranges from {approx}1000 to {approx}100,000 km. The binary orbits have eccentricities from e = 0 to {approx}1, with the majority having e < 0.6. The binary orbit inclinations with respect to the initial angular momentum of the swarm range from i = 0 to {approx}90{sup 0}, with most cases having i < 50{sup 0}. The total binary mass represents a characteristic fraction of the collapsing swarm's total initial mass, M{sub tot}, suggesting M{sub tot} equivalent to that of a radius {approx}100-250 km compact object. Our binary formation mechanism also implies that the primary and secondary components in each binary pair should have identical bulk composition, which is consistent with the current photometric data. We discuss the applicability of our results to the Pluto-Charon, Orcus-Vanth, (617) Patroclus

  12. ARTIST'S VIEW OF KUIPER BELT OBJECT 1998 WW31

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This is an artist's view of a Kuiper Belt binary object, called 1998 WW31. These icy bodies orbit each other at the fringe of our solar system. The illustration depicts one member of the duo in the foreground; its companion - the dark, round object - is in the background. The objects are about the same size. Both are illuminated from behind by the Sun [the white dot at upper left]. Like other Kuiper Belt objects, this duo orbits the Sun, completing a circuit every 301 years. The planet Pluto orbits the Sun every 248 years. Credit: NASA and G. Bacon (Space Telescope Science Institute)

  13. Test of IR arrays on the Kuiper Airborne Observatory

    NASA Technical Reports Server (NTRS)

    Russell, R. W.; Rossano, G. S.; Lynch, D. K.; Colon-Bonet, G. T.; Hackwell, J. A.

    1986-01-01

    NASA's Kuiper Airborne Observatory, which is a C-141 transport aircraft equipped with a 90-cm, all-reflective altazimuth telescope, has been engaged in the Kuiper Infrared Technology Experiment. Attention is presently given to the Experiment's flight series for state-of-the-art two-dimensional, 500-element arrays that use either blocked impurity band or bulk silicon devices. The switched FET readout scheme used on the three arrays flown thus far yields exceptionally low crosstalk. System sensitivities are found to be sufficient for the detection of both pointlike and extended sources; several of each type have been used in staring and scanning experiments.

  14. Kuiper Belt Objects Along the Pluto Express Path

    NASA Technical Reports Server (NTRS)

    Jewitt, David C.

    1998-01-01

    The science objective of this work was to identify objects in the Kuiper Belt which will, in the 5 years following Pluto encounter, be close to the flight path of NASA's Pluto-Kuiper Express. Currently, launch is scheduled for 2004 with a flight time of about 1 decade. Early identification of post-Pluto targets is important for mission design and orbit refinement. An object or objects close enough to the flight path can be visited and studied at high resolution, using only residual gas in the thrusters to affect a close encounter.

  15. 20 CFR 660.100 - What is the purpose of title I of the Workforce Investment Act of 1998?

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 20 Employees' Benefits 4 2014-04-01 2014-04-01 false What is the purpose of title I of the Workforce Investment Act of 1998? 660.100 Section 660.100 Employees' Benefits EMPLOYMENT AND TRAINING ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) INTRODUCTION TO THE REGULATIONS FOR WORKFORCE INVESTMENT...

  16. 20 CFR 403.100 - When can an SSA employee testify or produce information or records in legal proceedings?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... CFR parts 401 and 402. A request for both testimony and records or other information is considered two... 20 Employees' Benefits 2 2010-04-01 2010-04-01 false When can an SSA employee testify or produce information or records in legal proceedings? 403.100 Section 403.100 Employees' Benefits SOCIAL...

  17. The New Horizons Mission to Pluto and the Kuiper Belt

    NASA Astrophysics Data System (ADS)

    Weaver, H. A.; Stern, S. A.; New Horizons Science; Engineering Team

    New Horizons, which initiates the NASA New Frontiers program of mid-sized missions, will provide the first scientific reconnaissance of the Pluto-Charon system and is scheduled for launch in January 2006. An encounter with Jupiter at a flyby distance of ˜32-45 RJ about 13 months after launch provides a gravity boost for the spacecraft's journey to Pluto and practice for the Pluto encounter, in addition to providing an opportunity to perform a valuable set of scientific measurements within the jovian system. New Horizons carries a sophisticated suite of instruments to perform ultraviolet and infrared spectroscopy, panchromatic and color optical imaging, and charged particle and dust measurements, all within a spacecraft having a total mass of ˜465 kg and total power output of ˜210 W at the time of Pluto encounter in July 2015. The primary scientific objectives of the New Horizons are to characterize the global geology and morphology of Pluto and Charon, map the surface composition of Pluto and Charon, and characterize the neutral atmosphere and its escape rate, but many other important scientific objectives will be addressed as well. New Horizons has the capability to image Pluto with a resolution exceeding that provided by the Hubble Space Telescope for at least 90 days prior to closest approach at a distance of ˜10,000 km from the surface, at which time a resolution of ˜100 m will be achieved for selected regions near the terminator. After encounter, the spacecraft will pass through the shadows of both Pluto and Charon, which enables radio and ultraviolet occultation measurements of their atmospheres. If an extended mission phase is approved, the spacecraft will be re-targeted to encounter one or more Kuiper belt objects (KBOs), roughly 3 years after the Pluto encounter at a heliocentric distance of ˜42 AU. The scientific objectives for the KBO encounters are similar to those for the Pluto encounter.

  18. NEP for a Kuiper Belt Object Rendezvous Mission

    SciTech Connect

    HOUTS,MICHAEL G.; LENARD,ROGER X.; LIPINSKI,RONALD J.; PATTON,BRUCE; POSTON,DAVID I.; WRIGHT,STEVEN A.

    1999-11-03

    Kuiper Belt Objects (KBOs) are a recently-discovered set of solar system bodies which lie at about the orbit of Pluto (40 AU) out to about 100 astronomical units (AU). There are estimated to be about 100,000 KBOS with a diameter greater than 100 km. KBOS are postulated to be composed of the pristine material which formed our solar system and may even have organic materials in them. A detailed study of KBO size, orbit distribution, structure, and surface composition could shed light on the origins of the solar system and perhaps even on the origin of life in our solar system. A rendezvous mission including a lander would be needed to perform chemical analysis of the surface and sub-surface composition of KBOS. These requirements set the size of the science probe at around a ton. Mission analyses show that a fission-powered system with an electric thruster could rendezvous at 40 AU in about 13.0 years with a total {Delta}V of 46 krnk. It would deliver a 1000-kg science payload while providing ample onboard power for relaying data back to earth. The launch mass of the entire system (power, thrusters, propellant, navigation, communication, structure, science payload, etc.) would be 7984 kg if it were placed into an earth-escape trajectory (C=O). Alternatively, the system could be placed into a 700-km earth orbit with more propellant,yielding a total mass in LEO of 8618 kg, and then spiral out of earth orbit to arrive at the KBO in 14.3 years. To achieve this performance, a fission power system with 100 kW of electrical power and a total mass (reactor, shield, conversion, and radiator) of about 2350 kg. Three possible configurations are proposed: (1) a UZrH-fueled, NaK-cooled reactor with a steam Rankine conversion system, (2) a UN-fueled gas-cooled reactor with a recuperated Brayton conversion system, and (3) a UN-fueled heatpipe-cooled reactor with a recuperated Brayton conversion system. (Boiling and condensation in the Rankine system is a technical risk at present

  19. Size and Albedo of the Kuiper Belt Object 55636

    NASA Astrophysics Data System (ADS)

    Elliot, James L.; Person, M. J.; Zuluaga, C. A.; Bosh, A. S.; Adams, E. R.; Brothers, T. C.; Gulbis, A. A. S.; Levine, S. E.; Lockhart, M.; Zangari, A. M.; Babcock, B. A.; DuPré, K.; Pasachoff, J. M.; Souza, S. P.; Rosing, W.; Secrest, N.

    2010-10-01

    Due to the small sizes and great distances of Kuiper belt objects (KBOs), it is difficult to determine their diameters. We report multi-chord observations of a KBO stellar occultation, which occurred on 2009 October 9 (Elliot, J. L., et al. 2010, Nature, 465, 897). We set up a network of 21 telescopes at 18 stations, spanning a distance of 5920 km perpendicular to the predicted shadow path for the 2009 October 9 stellar occultation by the KBO 55636. Of these stations, seven could not observe due to weather, nine reported non-detections, and two observed an occultation, both in Hawai'i: the 2.0-m Faulkes North telescope at Haleakala and a 0.36-m portable telescope at the Visitor Information Station at the Onizuka Center for International Astronomy on Mauna Kea (located at the Mauna Kea Mid Level). We find that 55636 (2002 TX300), which is a member of the water-ice rich Haumea KBO collisional family (Brown, M. E., et al. 2007, Nature, 446, 294), has a mean radius of 143 ± 5 km (for a circular solution). Allowing for possible elliptical shapes we find a geometric albedo of 0.88 +0.15/-0.06 in the V photometric band. This firmly establishes that 55636 is smaller than previously thought and like its parent body, Haumea, is among the most highly reflective objects in the Solar System. Dynamical calculations by two groups indicate that the collision that created 55636 occurred at least 1 Gyr ago (Ragozzine, D., & Brown, M. E. 2007, AJ, 134, 2160; Schlichting, H. E., & Sari, R. 2009, ApJ, 700, 1242), which implies either that 55636 has an active resurfacing mechanism, or that fresh water ice in the outer solar system can persist for Gyr timescales. This work was supported, in part by NASA Grants NNX10AB27G (MIT), NNX08AO50G (Williams College), and NNH08AI17I (USNO-FS).

  20. Venus - 600 Kilometer Segment of Longest Channel on Venus

    NASA Technical Reports Server (NTRS)

    1991-01-01

    This compressed resolution radar mosaic from Magellan at 49 degrees north latitude, 165 degrees east longitude with dimensions of 460 by 460 kilometers (285 by 285 miles), shows a 600 kilometers (360 mile segment of the longest channel discovered on Venus to date. The channel is approximately 1.8 kilometers (1.1 miles) wide. At more than 7,000 kilometers (4,200 miles) long, it is several hundred kilometers longer than the Nile River, Earth's longest river, thus making it the longest known channel in the solar system. Both ends of the channel are obscured, however, so its original length is unknown. The channel was initially discovered by the Soviet Venera 15-16 orbiters which, in spite of their one kilometer resolution, detected more than 1,000 kilometers (620 miles) of the channel. These channel-like features are common on the plains of Venus. In some places they appear to have been formed by lava which may have melted or thermally eroded a path over the plains' surface. Most are 1 to 3 kilometers (0.6 to 2 miles) wide. They resemble terrestrial meandering rivers in some aspects, with meanders, cutoff bows and abandoned channel segments. However, Venus channels are not as tightly sinuous as terrestrial rivers. Most are partly buried by younger lava plains, making their sources difficult to identify. A few have vast radar-dark plains units associated with them, suggesting large flow volumes. These channels, with large deposits appear to be older than other channel types, as they are crossed by fractures and wrinkle ridges, and are often buried by other volcanic materials. In addition, they appear to run both upslope and downslope, suggesting that the plains were warped by regional tectonism after channel formation. Resolution of the Magellan data is about 120 meters (400 feet).

  1. Layered Model for Radiation-Induced Chemical Evolution of Icy Surface Composition on Kuiper Belt and Oort Cloud Bodies

    NASA Technical Reports Server (NTRS)

    Cooper, John F.; Hill, Matthew E.; Richardson, John D.; Sturner, Steven J.

    2010-01-01

    The diversity of albedos and surface colors on observed Kuiper Belt and Inner Oort Cloud objects remains to be explained in terms of competition between primordial intrinsic versus exogenic drivers of surface and near-surface evolution. Earlier models have attempted without success to attribute this diversity to the relations between surface radiolysis from cosmic ray irradiation and gardening by meteoritic impacts. A more flexible approach considers the different depth-dependent radiation profiles produced by low-energy plasma, suprathermal, and maximally penetrating charged particles of the heliospheric and local interstellar radiation environments. Generally red objects of the dynamically cold (low inclination, circular orbit) Classical Kuiper Belt might be accounted for from erosive effects of plasma ions and reddening effects of high energy cosmic ray ions, while suprathermal keV-MeV ions could alternatively produce more color neutral surfaces. The deepest layer of more pristine ice can be brought to the surface from meter to kilometer depths by larger impact events and potentially by cryovolcanic activity. The bright surfaces of some larger objects, e.g. Eris, suggest ongoing resurfacing activity. Interactions of surface irradiation, resultant chemical oxidation, and near-surface cryogenic fluid reservoirs have been proposed to account for Enceladus cryovolcanism and may have further applications to other icy irradiated bodies. The diversity of causative processes must be understood to account for observationally apparent diversities of the object surfaces.

  2. Layered Model for Radiation-Induced Chemical Evolution of Icy Surface Composition on Kuiper Belt and Oort Cloud Bodies

    NASA Astrophysics Data System (ADS)

    Cooper, John F.; Hill, M. E.; Richardson, J. D.; Sturner, S. J.

    2010-10-01

    The diversity of albedos and surface colors on observed Kuiper Belt and Inner Oort Cloud objects remains to be explained in terms of competition between primordial intrinsic versus exogenic drivers of surface and near-surface evolution. Earlier models have attempted without success to attribute this diversity to the relations between surface radiolysis from cosmic ray irradiation and gardening by meteoritic impacts. A more flexible approach considers the different depth-dependent radiation profiles produced by low-energy plasma, suprathermal, and maximally penetrating charged particles of the heliospheric and local interstellar radiation environments. Generally red objects of the dynamically cold (low inclination, circular orbit) Classical Kuiper Belt might be accounted for from erosive effects of plasma ions and reddening effects of high energy cosmic ray ions, while suprathermal keV-MeV ions could alternatively produce more color neutral surfaces. The deepest layer of more pristine ice can be brought to the surface from meter to kilometer depths by larger impact events and potentially by cryovolcanic activity. The bright surfaces of some larger objects, e.g. Eris, suggest ongoing resurfacing activity. Interactions of surface irradiation, resultant chemical oxidation, and near-surface cryogenic fluid reservoirs have been proposed to account for Enceladus cryovolcanism (Cooper et al., Plan. Sp. Sci., 2009) and may have further applications to other icy irradiated bodies. The diversity of causative processes must be understood to account for observationally apparent diversities of the object surfaces.

  3. Far-Infrared Astronomy with The Kuiper Airborne Observatory

    NASA Technical Reports Server (NTRS)

    Hildebrand, Roger, H.

    1997-01-01

    This report summarizes work made possible by NASA's Kuiper Airborne Observatory. The results of the work have appeared in over 80 papers. The publications fall in three main areas: instrumentation, observations, and analysis. Although there is considerable overlap between these categories it will be convenient to group them separately.

  4. Three Classes of Kuiper Belt Objects: Theory and Observations

    NASA Technical Reports Server (NTRS)

    Holman, Mathew J.; Boyce, J. (Technical Monitor)

    2001-01-01

    As part of the Origins of Solar Systems program our team conducted a dynamically motivated search for three classes of Kuiper belt objects (distant comets near and beyond the orbit of Neptune). Our strategy has been to exploit variations in the sky density of Kuiper belt that result from the gravitational influence of Neptune. By searching two regions of the sky, one nearly 90 degrees from Neptune and one nearly opposite Neptune, and comparing the number of objects discovered in each region we are able to constrain the relative populations of resonant and non-resonant objects, a fundamental quantity in Kuiper belt formation models. In addition, by searching at a variety of angles above the plane of the solar system we have constrained the inclination distribution of Kuiper belt objects. We have conducted four searches for this program. One was in February 1999 and August 2000 at the Canada-France-Hawaii telescope (3.6-meter), and another was in May 1999 and Oct. 2000 at the Kitt Peak National Observatory (4-meter). In addition, a search for Uranian satellites was conducted.

  5. 25 CFR 20.100 - What definitions clarify the meaning of the provisions of this part?

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... threat to life, safety, or health as specified in §§ 20.327 and 20.328. Emergency means a situation where... life threatening situations that may cause loss or damage of personal possessions; (6)...

  6. 25 CFR 20.100 - What definitions clarify the meaning of the provisions of this part?

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... threat to life, safety, or health as specified in §§ 20.327 and 20.328. Emergency means a situation where... life threatening situations that may cause loss or damage of personal possessions; (6)...

  7. The Whipple Mission: Exploring the Kuiper Belt and the Oort Cloud

    NASA Astrophysics Data System (ADS)

    Alcock, C.; Brown, M. E.; Gauron, T.; Heneghan, C.; Holman, M. J.; Kenter, A.; Kraft, R.; Lee, R.; Livingston, J.; Mcguire, J.; Murray, S. S.; Murray-Clay, R.; Nulsen, P.; Payne, M. J.; Schlichting, H.; Trangsrud, A.; Vrtilek, J.; Werner, M.

    2014-12-01

    Whipple will characterize the small body populations of the Kuiper Belt and the Oort Cloud with a blind occultation survey, detecting objects when they briefly (~1 second) interrupt the light from background stars, allowing the detection of much more distant and/or smaller objects than can be seen in reflected sunlight. Whipple will reach much deeper into the unexplored frontier of the outer solar system than any other mission, current or proposed. Whipple will look back to the dawn of the solar system by discovering its most remote bodies where primordial processes left their imprint. Specifically, Whipple will monitor large numbers of stars at high cadences (~12,000 stars at 20 Hz to examine Kuiper Belt events; as many as ~36,000 stars at 5 Hz to explore deep into the Oort Cloud, where events are less frequent). Analysis of the detected events will allow us to determine the size spectrum of bodies in the Kuiper Belt with radii as small as ~1 km. This will allow the testing of models of the growth and later collisional erosion of planetesimals in the early solar system. Whipple will explore the Oort Cloud, detecting objects as far out as ~10,000 AU. This will be the first direct exploration of the Oort Cloud since the original hypothesis of 1950. Whipple is a Discovery class mission that will be proposed to NASA in response to the 2014 Announcement of Opportunity. The mission is being developed jointly by the Smithsonian Astrophysical Observatory, Jet Propulsion Laboratories, and Ball Aerospace & Technologies, with telescope optics from L-3 Integrated Optical Systems.

  8. The Whipple Mission: Exploring the Kuiper Belt and the Oort Cloud

    NASA Astrophysics Data System (ADS)

    Alcock, Charles; Brown, Michael; Gauron, Tom; Heneghan, Cate; Holman, Matthew; Kenter, Almus; Kraft, Ralph; Livingston, John; Murray, Stephen; Murray-Clay, Ruth; Nulsen, Paul; Payne, Matthew; Schlichting, Hilke; Trangsrud, Amy; Vrtilek, Jan; Werner, Michael

    2014-11-01

    Whipple will characterize the small body populations of the Kuiper Belt and the Oort Cloud with a blind occultation survey, detecting objects when they briefly 1 second) interrupt the light from background stars, allowing the detection of much more distant and/or smaller objects than can be seen in reflected sunlight. Whipple will reach much deeper into the unexplored frontier of the outer solar system than any other mission, current or proposed. Whipple will look back to the dawn of the solar system by discovering its most remote bodies where primordial processes left their imprint.Specifically, Whipple will monitor large numbers of stars at high cadences 12,000 stars at 20 Hz to examine Kuiper Belt events; as many as ~36,000 stars at 5 Hz to explore deep into the Oort Cloud, where events are less frequent). Analysis of the detected events will allow us to determine the size spectrum of bodies in the Kuiper Belt with radii as small as ~1 km. This will allow the testing of models of the growth and later collisional erosion of planetesimals in the early solar system. Whipple will explore the Oort Cloud, detecting objects as far out as ~10,000 AU. This will be the first direct exploration of the Oort Cloud since the original hypothesis of 1950.Whipple is a Discovery class mission that will be proposed to NASA in response to the 2014 Announcement of Opportunity. The mission is being developed jointly by the Smithsonian Astrophysical Observatory, Jet Propulsion Laboratories, and Ball Aerospace & Technologies, with telescope optics from L-3 Integrated Optical Systems.

  9. The Whipple Mission: Exploring the Kuiper Belt and the Oort Cloud

    NASA Astrophysics Data System (ADS)

    Alcock, Charles; Brown, Michael; Gauron, Tom; Heneghan, Cate; Holman, Matthew; Kenter, Almus; Kraft, Ralph; Livingstone, John; Murray-Clay, Ruth; Nulsen, Paul; Payne, Matthew; Schlichting, Hilke; Trangsrud, Amy; Vrtilek, Jan; Werner, Michael

    2015-11-01

    Whipple will characterize the small body populations of the Kuiper Belt and the Oort Cloud with a blind occultation survey, detecting objects when they briefly (~1 second) interrupt the light from background stars, allowing the detection of much more distant and/or smaller objects than can be seen in reflected sunlight. Whipple will reach much deeper into the unexplored frontier of the outer solar system than any other mission, current or proposed. Whipple will look back to the dawn of the solar system by discovering its most remote bodies where primordial processes left their imprint.Specifically, Whipple will monitor large numbers of stars at high cadences (~12,000 stars at 20 Hz to examine Kuiper Belt events; as many as ~36,000 stars at 5 Hz to explore deep into the Oort Cloud, where events are less frequent). Analysis of the detected events will allow us to determine the size spectrum of bodies in the Kuiper Belt with radii as small as ~1 km. This will allow the testing of models of the growth and later collisional erosion of planetesimals in the early solar system. Whipple will explore the Oort Cloud, potentially detecting objects as far out as ~10,000 AU. This will be the first direct exploration of the Oort Cloud since the original hypothesis of 1950.Whipple is a Discovery class mission that was proposed to NASA in response to the 2014 Announcement of Opportunity. The mission is being developed jointly by the Smithsonian Astrophysical Observatory, Jet Propulsion Laboratories, and Ball Aerospace & Technologies, with telescope optics from L-3 Integrated Optical Systems and imaging sensors from Teledyne Imaging Sensors.

  10. The Whipple Mission: Exploring the Kuiper Belt and the Oort Cloud

    NASA Astrophysics Data System (ADS)

    Holman, Matthew J.; Alcock, Charles; Kenter, Almus T.; Kraft, Ralph P.; Nulsen, Paul; Payne, Matthew John; Vrtilek, Jan M.; Murray, Stephen S.; Murray-Clay, Ruth; Schlichting, Hilke; Brown, Michael E.; Livingston, John H.; Trangsrud, Amy R.; Werner, Michael W.

    2015-01-01

    Whipple will characterize the small body populations of the Kuiper Belt and the Oort Cloud with a blind occultation survey, detecting objects when they briefly (~1 second) interrupt the light from background stars, allowing the detection of much more distant and/or smaller objects than can be seen in reflected sunlight. Whipple will reach much deeper into the unexplored frontier of the outer solar system than any other mission, current or proposed. Whipple will look back to the dawn of the solar system by discovering its most remote bodies where primordial processes left their imprint.Specifically, Whipple will monitor large numbers of stars at high cadences (~12,000 stars at 20 Hz to examine Kuiper Belt events; as many as ~36,000 stars at 5 Hz to explore deep into the Oort Cloud, where events are less frequent). Analysis of the detected events will allow us to determine the size spectrum of bodies in the Kuiper Belt with radii as small as ~1 km. This will allow the testing of models of the growth and later collisional erosion of planetesimals in the earlysolar system. Whipple will explore the Oort Cloud, detecting objects as far out as ~10,000 AU. This will be the first direct exploration of the Oort Cloud since the original hypothesis of 1950.Whipple is a Discovery class mission that will be proposed to NASA in response to the upcoming Announcement of Opportunity. The mission is being developed jointly by the Smithsonian Astrophysical Observatory, Jet Propulsion Laboratory, and Ball Aerospace & Technologies, with telescope optics from L-3 Integrated Optical Systems.

  11. Predicted performance of InP solar cells in Cassegrainian and slats space concentrator arrays at 20 to 100 AM0, 80 to 100 C

    NASA Technical Reports Server (NTRS)

    Goradia, Chandra; Thesling, William; Goradia, Manju Ghalla; Weinberg, Irving; Swartz, Clifford K.

    1989-01-01

    Researchers have calculated the expected performance dependence of near-optimally designed shallow homojunction n+pp+InP solar cells on incident intensities up 200 AM0 and temperatures up to 100 C (373K). Both circular and rectangular cells have been considered, the former for use in a Cassegrainian concentrator array at 100 AM0, 80 to 100 C and the latter for use in a Slats type concentrator array at 20 AM0 80 to 100 C. Calculation of the temperature dependence of the performance parameters I sub sc, V sub oc, FF and eta was done by first verifying that the use of the measured temperature variation of I sub sc, of the best published value of the temperature dependence of the bandgap of InP, and of the temperature dependences of the lifetimes and mobilities of electrons and holes the same as in equivalently doped GaAs, gave calculated results that closely matched measured data on the temperature variation of I sub sc, V sub oc, and FF of four existing InP cells at 1 AM0. It was then assumed that the same temperature dependences of I sub sc, the bandgap and lifetimes and mobilities would hold in the near-optimally designed cells at the higher concentrations.

  12. 11 CFR 100.24 - Federal election activity (2 U.S.C. 431(20)).

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    .... (ii) Generic campaign activity, as defined in 11 CFR 100.25. (iii) Get-out-the-vote activity. (3) A... association of State or local candidates, enabling visitors to download a voter registration form or...

  13. 11 CFR 100.24 - Federal election activity (2 U.S.C. 431(20)).

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    .... (ii) Generic campaign activity, as defined in 11 CFR 100.25. (iii) Get-out-the-vote activity. (3) A... association of State or local candidates, enabling visitors to download a voter registration form or...

  14. 11 CFR 100.24 - Federal election activity (2 U.S.C. 431(20)).

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    .... (ii) Generic campaign activity, as defined in 11 CFR 100.25. (iii) Get-out-the-vote activity. (3) A... association of State or local candidates, enabling visitors to download a voter registration form or...

  15. 11 CFR 100.24 - Federal election activity (2 U.S.C. 431(20)).

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... defined in 11 CFR 100.25. (iii) Get-out-the-vote activity. (3) A public communication that refers to a... polling places; and (ii) Offering to transport or actually transporting voters to the polls. (4)...

  16. Photographer : JPL Range : 312, 000 kilometers (195,000 miles) This photo of Ganymede (Ice Giant)

    NASA Technical Reports Server (NTRS)

    1979-01-01

    Photographer : JPL Range : 312, 000 kilometers (195,000 miles) This photo of Ganymede (Ice Giant) was taken from Voyager 2 and shows features down to about 5 to 6 kilometers across. Different types of terrain common on Ganymede's surface are visible. The boundary of the largest region of dark ancient terrain on Ganymede can be seen to the east (right), revealing some of the light linear features which may be all that remains of a large ancient impact structure similar to the large ring structure on Callisto. The broad light regions running through the image are the typical grooved structures seen within another example of what might be evidence of large scale lateral motion in Ganymede's crust. The band of grooved terrain (about 100 kilometers wide) in this region appears to be offset by 50 kilometers or more on the left hand edge by a linear feature perpendicular to it. A feature similar to this one was previously discovered by Voyager 1. These are the first clear examples of strike-slip style faulting on any planet other than Earth. Many examples of craters of all ages can be seen in this image, ranging from fresh, bright ray craters to large, subdued circular markings thought to be the 'scars' of large ancient impacts that have been flatteded by glacier-like flows.

  17. The Development of Children's Adaptive Expertise in the Number Domain 20 to 100

    ERIC Educational Resources Information Center

    Torbeyns, Joke; Verschaffel, Lieven; Ghesquiere, Pol

    2006-01-01

    The aim of the study was to analyze the development of children's adaptive expertise in computing sums and differences up to 100. We defined the adaptive nature of children's strategy choices on the basis of problem (addition, subtraction), achievement, and strategy performance (accuracy, speed). Sixty-nine 2nd graders of high, above-average, or…

  18. NEPTUNE ON TIPTOES: DYNAMICAL HISTORIES THAT PRESERVE THE COLD CLASSICAL KUIPER BELT

    SciTech Connect

    Wolff, Schuyler; Dawson, Rebekah I.; Murray-Clay, Ruth A. E-mail: rdawson@cfa.harvard.edu

    2012-02-20

    The current dynamical structure of the Kuiper Belt was shaped by the orbital evolution of the giant planets, especially Neptune, during the era following planet formation when the giant planets may have undergone planet-planet scattering and/or planetesimal-driven migration. Numerical simulations of this process, while reproducing many properties of the Belt, fail to generate the high inclinations and eccentricities observed for some objects while maintaining the observed dynamically 'cold' population. We present the first of a three-part parameter study of how different dynamical histories of Neptune sculpt the planetesimal disk. Here we identify which dynamical histories allow an in situ planetesimal disk to remain dynamically cold, becoming today's cold Kuiper Belt population. We find that if Neptune undergoes a period of elevated eccentricity and/or inclination, it secularly excites the eccentricities and inclinations of the planetesimal disk. We demonstrate that there are several well-defined regimes for this secular excitation, depending on the relative timescales of Neptune's migration, the damping of Neptune's orbital inclination and/or eccentricity, and the secular evolution of the planetesimals. We model this secular excitation analytically in each regime, allowing for a thorough exploration of parameter space. Neptune's eccentricity and inclination can remain high for a limited amount of time without disrupting the cold classical belt. In the regime of slow damping and slow migration, if Neptune is located (for example) at 20 AU, then its eccentricity must stay below 0.18 and its inclination below 6 Degree-Sign .

  19. 20 CFR 30.100 - In general, how does an employee file an initial claim for benefits?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 20 Employees' Benefits 1 2011-04-01 2011-04-01 false In general, how does an employee file an... Claims for Benefits Under Eeoicpa § 30.100 In general, how does an employee file an initial claim for benefits? (a) To claim benefits under EEOICPA, an employee must file a claim in writing. Form EE-1...

  20. The Kuiper belt and the solar system's comet disk.

    PubMed

    Gladman, Brett

    2005-01-01

    Our planetary system is embedded in a small-body disk of asteroids and comets, vestigial remnants of the original planetesimal population that formed the planets. Once formed, those planets dispersed most of the remaining small bodies. Outside of Neptune, this process has left our Kuiper belt and built the Oort cloud, as well as emplacing comets into several other identifiable structures. The orbits in these structures indicate that our outer solar system's comet disk was shaped by a variety of different physical processes, which teach us about how the giant planets formed. Recent work has shown that the scattered disk is the most likely source of short-period comets. Moreover, a growing body of evidence indicates that the sculpting of the Kuiper belt region may have involved large-scale planetary migration, the presence of other rogue planetary objects in the disk, and/or the close passage of other stars in the Sun's birth cluster. PMID:15637267

  1. Energetics of vertical kilometer foot races; is steeper cheaper?

    PubMed

    Giovanelli, Nicola; Ortiz, Amanda Louise Ryan; Henninger, Keely; Kram, Rodger

    2016-02-01

    Vertical kilometer foot races consist of a 1,000-m elevation gain in <5,000 m of overall distance, and the inclines of the fastest courses are ∼30°. Previous uphill locomotion studies have focused on much shallower angles. We aimed to quantify the metabolic costs of walking and running on very steep angles and to biomechanically distinguish walking from running. Fifteen runners (10 male, 5 female, 32.9 ± 7.5 yr, 1.75 ± 0.09 m, 64.3 ± 9.1 kg) walked and ran for 5 min at seven different angles (9.4, 15.8, 20.4, 24.8, 30.0, 35.0, and 39.2°) all at a fixed vertical velocity (0.35 m/s). We measured the metabolic rates and calculated the vertical costs of walking (Cwvert) and running (Crvert). Using video analysis, we determined stride frequency, stride length, and duty factor (fraction of stride that each foot is in ground contact). At all angles other than 9.4°, Cwvert was cheaper than Crvert (average -8.45 ± 1.05%; P < 0.001). Further, broad minima for both Cwvert and Crvert existed between 20.4 and 35.0° (average Cwvert 44.17 ± 0.41 J·kg(-1)·m(-1) and average Crvert 48.46 ± 0.35 J·kg(-1)·m(-1)). At all angles and speeds tested, both walking and running involved having at least one foot on the ground at all times. However, in walking, stride frequency and stride length were ∼28% slower and longer, respectively, than in running. In conclusion, we found that there is a range of angles for which energy expenditure is minimized. At the vertical velocity tested, on inclines steeper than 15.8°, athletes can reduce their energy expenditure by walking rather than running. PMID:26607247

  2. THE DENSITY OF MID-SIZED KUIPER BELT OBJECT 2002 UX25 AND THE FORMATION OF THE DWARF PLANETS

    SciTech Connect

    Brown, M. E.

    2013-12-01

    The formation of the largest objects in the Kuiper belt, with measured densities of ∼1.5 g cm{sup –3} and higher, from the coagulation of small bodies, with measured densities below 1 g cm{sup –3}, is difficult to explain without invoking significant porosity in the smallest objects. If such porosity does occur, measured densities should begin to increase at the size at which significant porosity is no longer supported. Among the asteroids, this transition occurs for diameters larger than ∼350 km. In the Kuiper belt, no density measurements have been made between ∼350 km and ∼850 km, the diameter range where porosities might first begin to drop. Objects in this range could provide key tests of the rock fraction of small Kuiper belt objects (KBOs). Here we report the orbital characterization, mass, and density determination of the 2002 UX25 system in the Kuiper belt. For this object, with a diameter of ∼650 km, we find a density of 0.82 ± 0.11 g cm{sup –3}, making it the largest solid known object in the solar system with a measured density below that of pure water ice. We argue that the porosity of this object is unlikely to be above ∼20%, suggesting a low rock fraction. If the currently measured densities of KBOs are a fair representation of the sample as a whole, creating ∼1000 km and larger KBOs with rock mass fractions of 70% and higher from coagulation of small objects with rock fractions as low as those inferred from 2002 UX25 is difficult.

  3. Corralling a Distant Planet with Extreme Resonant Kuiper Belt Objects

    NASA Astrophysics Data System (ADS)

    Malhotra, Renu; Volk, Kathryn; Wang, Xianyu

    2016-06-01

    The four longest period Kuiper Belt objects have orbital periods close to integer ratios with each other. A hypothetical planet with an orbital period of ˜17,117 years and a semimajor axis ˜665 au would have N/1 and N/2 period ratios with these four objects. The orbital geometries and dynamics of resonant orbits constrain the orbital plane, the orbital eccentricity, and the mass of such a planet as well as its current location in its orbital path.

  4. Corralling a Distant Planet with Extreme Resonant Kuiper Belt Objects

    NASA Astrophysics Data System (ADS)

    Malhotra, Renu; Volk, Kathryn; Wang, Xianyu

    2016-06-01

    The four longest period Kuiper Belt objects have orbital periods close to integer ratios with each other. A hypothetical planet with an orbital period of ∼17,117 years and a semimajor axis ∼665 au would have N/1 and N/2 period ratios with these four objects. The orbital geometries and dynamics of resonant orbits constrain the orbital plane, the orbital eccentricity, and the mass of such a planet as well as its current location in its orbital path.

  5. Cosmic Ray Mantle Visibility on Kuiper Belt Objects

    NASA Technical Reports Server (NTRS)

    Cooper, John F.; Hill, Matt E.; Richardson, J. D.; Sturner, S. J.

    2006-01-01

    Optically red objects constitute the dynamically cold, old component of the Classical Kuiper Belt (40 - 47 AU) with heliocentric orbits of low eccentricity and inclination. The red colors likely arise from primordial mixed ices processed by irradiation to meters in surface depth over the past four billion years, since the time of giant planet migration and Kuiper Belt stirring, at relatively moderate dosages of 60 gigarads provided by galactic cosmic ray protons and heavier ions. The red cosmic ray mantle is uniformly visible on the cold classical objects beneath a minimally thin eroded layer of more neutrally colored material arising from cumulative effects of heliospheric particle irradiation. The radiation fluxes are lowest in the middle heliospheric region containing the Classical Kuiper Belt and increase from there both towards and away from the Sun. Despite increasing irradiation at various times of solar system history from increases in solar and interstellar ion fluxes, the red object region has apparently never reached sufficiently high dosage levels to neutralize in color the red mantle material. Erosion processes, including plasma sputtering and micrometeroid impacts, act continuously to reduce thickness of the upper neutral crust and expose the cosmic ray mantle. A deeper layer at tens of meters and more may consist of relatively unprocessed ices that can erupt to the surface by larger impacts or cryovolcanism and account for brighter surfaces of larger objects such as 2003 UB313. Surface colors among the Kuiper Belt and other icy objects of the outer solar system are then a function, assuming uniform primordial composition, of relative thickness for the three layers and of the resurfacing age dependent on the orbital and impact history of each object.

  6. Origin Hypotheses for Kilometer-Scale Mounds on Dwarf Planet Ceres

    NASA Astrophysics Data System (ADS)

    Sizemore, Hanna G.; Platz, Thomas; Schmidt, Britney E.; Scully, Jennifer E. C.; Russell, Christopher T.; Mest, Scott C.; Crown, David A.; Sykes, Mark V.; Hughson, Kynan H. G.; Chilton, Heather T.; Williams, David A.; Pieters, Carle M.; Marchi, Simone; Travis, Bryan; Raymond, Carol A.

    2015-11-01

    The Dawn Framing Camera has revealed numerous domical to conical features on Ceres, which may have relevance to the presence and history of near-surface ice. These features fall into two broad classes, large domes 10s to >100 km in diameter exhibiting 1-5 km of positive relief, and small mounds <10 km in diameter exhibiting sub-kilometer relief. Here, we propose three hypotheses for the origin of the ~150 small mounds identified thus far, and discuss morphological observations that could support each hypothesis as higher resolution data becomes available.Hypothesis 1: Kilometer-scale mounds are produced by localized eruption of cryomagma or hydrothermal material. Observational tests: Kilometer and sub-kilometer scale albedo variations; sub-kilometer flow features on individual mounds; localized vents; conical or domical shape. Challenge: Features are smaller than convective plumes expected from thermal evolution modeling.Hypothesis 2: Kilometer-scale mounds are analogous to terrestrial and martian pingos, which grow by drawing liquid water through a silicate matrix as a freezing front propagates downward. Observational tests: Mounds occurring on smooth material that floods or embays large-scale features; little or no local albedo variation; no small flows associated with individual mounds; domical or ring-shape; concentric or radial fractures on dome, or central depression. Challenge: Small Cerean mounds observed thus far are an order of magnitude larger than terrestrial or martian pingos.Hypothesis 3: Kilometer-scale mounds are rootless cones analogous to features observed on the surface of volcanic flows in volatile-rich regions of Earth and Mars. Rootless cones are produced when layers of fluid material inundate a region; localized devolatilization of a layer mobilizes clasts to form cone-shaped deposits. Observational tests: Mounds on smooth material that floods or embays large-scale features; conical, not domical, profile; large central

  7. 21 CFR 20.100 - Applicability; cross-reference to other regulations.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... file for an antibiotic drug, in § 514.10 of this chapter. (13) Methadone patient records, in § 291.505... chapter. (20) Investigational new drug notice for an antibiotic drug, in § 431.70 of this chapter. (21) Antibiotic drug file, in § 314.430 of this chapter. (22) Data and information submitted for biologics...

  8. 21 CFR 20.100 - Applicability; cross-reference to other regulations.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... file for an antibiotic drug, in § 514.10 of this chapter. (13) Methadone patient records, in § 291.505... chapter. (20) Investigational new drug notice for an antibiotic drug, in § 431.70 of this chapter. (21) Antibiotic drug file, in § 314.430 of this chapter. (22) Data and information submitted for biologics...

  9. 21 CFR 20.100 - Applicability; cross-reference to other regulations.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... file for an antibiotic drug, in § 514.10 of this chapter. (13) Methadone patient records, in § 291.505... chapter. (20) Investigational new drug notice for an antibiotic drug, in § 431.70 of this chapter. (21) Antibiotic drug file, in § 314.430 of this chapter. (22) Data and information submitted for biologics...

  10. 21 CFR 20.100 - Applicability; cross-reference to other regulations.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... file for an antibiotic drug, in § 514.10 of this chapter. (13) Methadone patient records, in § 291.505... chapter. (20) Investigational new drug notice for an antibiotic drug, in § 431.70 of this chapter. (21) Antibiotic drug file, in § 314.430 of this chapter. (22) Data and information submitted for biologics...

  11. 21 CFR 20.100 - Applicability; cross-reference to other regulations.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... file for an antibiotic drug, in § 514.10 of this chapter. (13) Methadone patient records, in § 291.505... chapter. (20) Investigational new drug notice for an antibiotic drug, in § 431.70 of this chapter. (21) Antibiotic drug file, in § 314.430 of this chapter. (22) Data and information submitted for biologics...

  12. The Era of Kilometer-Scale Neutrino Detectors

    DOE PAGESBeta

    Halzen, Francis; Katz, Uli

    2013-01-01

    Neutrino astronomy beyond the Sun was first imagined in the late 1950s; by the 1970s, it was realized that kilometer-scale neutrino detectors were required. The first such instrument, IceCube, transforms a cubic kilometer of deep and ultra-transparent Antarctic ice into a particle detector. KM3NeT, an instrument that aims to exploit several cubic kilometers of the deep Mediterranean sea as its detector medium, is in its final design stages. The scientific missions of these instruments include searching for sources of cosmic rays and for dark matter, observing Galactic supernova explosions, and studying the neutrinos themselves. Identifying the accelerators that produce Galacticmore » and extragalactic cosmic rays has been a priority mission of several generations of high-energy gamma-ray and neutrino telescopes; success has been elusive so far. Detecting the gamma-ray and neutrino fluxes associated with cosmic rays reaches a new watershed with the completion of IceCube, the first neutrino detector with sensitivity to the anticipated fluxes. In this paper, we will first revisit the rationale for constructing kilometer-scale neutrino detectors. We will subsequently recall the methods for determining the arrival direction, energy and flavor of neutrinos, and will subsequently describe the architecture of the IceCube and KM3NeT detectors.« less

  13. Sulfuric acid aerosol production at 30 kilometers over Antarctica

    SciTech Connect

    Hofmann, D.

    1987-09-01

    The author will use balloons of various sizes, instrumented with ozonesondes to measure in detail vertical profiles of ozone and temperature from the ground to about 29 kilometers above the surface. These measurements should indicate where in the column changes the ozone is being destroyed.

  14. From Kuiper Belt to Comet: The Shapes of the Nuclei

    NASA Astrophysics Data System (ADS)

    Jewitt, D.; Sheppard, S.; Fernandez, Y.

    2003-05-01

    It is widely believed that escaped objects from the Kuiper Belt are the source of both the Centaurs and the nuclei of the Jupiter Family Comets (JFCs). If the JFC nuclei are produced by collisional breakup of parent objects in the Kuiper Belt, then it is reasonable to expect that their shape distribution should be consistent with those of fragments produced in disintegrative laboratory experiments, or with the small main-belt asteroids (which are produced collisionally). We test this idea using a sample of eleven well-observed cometary nuclei. Our main result is that the nuclei are, on average, much more elongated than either the collisionally produced small main-belt asteroids or the fragments created in laboratory impact experiments. Several interpretations of this systematic shape difference are possible (including the obvious one that the JFC nuclei are not, after all, produced collisionally in the Kuiper Belt). Our preferred explanation, however, is that the asphericities of the nuclei have been modified by one or more processes of mass loss. An implication of this interpretation is that the JFC nuclei in our sample are highly evolved, having lost a major part of their original mass. In turn, this implies that the angular momenta of the nuclei are also non-primordial: the JFC nuclei are highly physically evolved objects. We will discuss the evidence supporting these conclusions. This work has been recently published in Astronomical Journal, 125, 3366-3377 (2003).

  15. A HYPOTHESIS FOR THE COLOR DIVERSITY OF THE KUIPER BELT

    SciTech Connect

    Brown, M. E.; Fraser, W. C.; Schaller, E. L.

    2011-10-01

    We propose a chemical and dynamical process to explain the surface colors of the Kuiper belt. In our hypothesis, the initial bulk compositions of the bodies themselves can be quite diverse-as is seen in comets-but the early surface compositions are set by volatile evaporation after the objects are formed. Strong gradients in surface composition, coupled with UV and particle irradiation, lead to the surface colors that are seen today. The objects formed in the inner part of the primordial belt retain only H{sub 2}O and CO{sub 2} as the major ice species on their surfaces. Irradiation of these species plausibly results in the dark neutrally colored centaurs and Kuiper belt objects (KBOs). Object formed further in the disk retain CH{sub 3}OH, which has been shown to lead to brighter redder surfaces after irradiation, as seen in the brighter redder centaurs and KBOs. Objects formed at the current location of the cold classical Kuiper belt uniquely retain NH{sub 3}, which has been shown to affect irradiation chemistry and could plausibly lead to the unique colors of these objects. We propose observational and experimental tests of this hypothesis.

  16. Crystalline water ice on the Kuiper belt object (50000) Quaoar.

    PubMed

    Jewitt, David C; Luu, Jane

    2004-12-01

    The Kuiper belt is a disk-like structure consisting of solid bodies orbiting the Sun beyond Neptune. It is the source of the short-period comets and the likely repository of the Solar System's most primitive materials. Surface temperatures in the belt are low ( approximately 50 K), suggesting that ices trapped at formation should have been preserved over the age of the Solar System. Unfortunately, most Kuiper belt objects are too faint for meaningful compositional study, even with the largest available telescopes. Water ice has been reported in a handful of objects, but most appear spectrally featureless. Here we report near-infrared observations of the large Kuiper belt object (50000) Quaoar, which reveal the presence of crystalline water ice and ammonia hydrate. Crystallinity indicates that the ice has been heated to at least 110 K. Both ammonia hydrate and crystalline water ice should be destroyed by energetic particle irradiation on a timescale of about 10(7) yr. We conclude that Quaoar has been recently resurfaced, either by impact exposure of previously buried (shielded) ices or by cryovolcanic outgassing, or by a combination of these processes. PMID:15592406

  17. SKARPS: The Search for Kuiper Belts around Radial-Velocity Planet Stars

    NASA Technical Reports Server (NTRS)

    Bryden, Geoffrey; Marshall, Jonathan; Stapelfeldt, Karl; Su, Kate; Wyatt, Mark

    2011-01-01

    The Search for Kuiper belts Around Radial-velocity Planet Stars - SKARPS -is a Herschel survey of solar-type stars known to have orbiting planets. When complete, the 100-star SKARPS sample will be large enough for a meaningful statistical comparison against stars not known to have planets. (This control sample has already been observed by Herschel's DUst around NEarby Stars - DUNES - key program). Initial results include previously known disks that are resolved for the first time and newly discovered disks that are fainter and colder than those typically detected by Spitzer. So far, with only half of the sample in hand, there is no measured correlation between inner RV planets and cold outer debris. While this is consistent with the results from Spitzer, it is in contrast with the relationship suggested by the prominent debris disks in imaged-planet systems.

  18. Optimization of un-tethered, low voltage, 20-100kHz flexural transducers for biomedical ultrasonics applications.

    PubMed

    Sunny, Youhan; Bawiec, Christopher R; Nguyen, An T; Samuels, Joshua A; Weingarten, Michael S; Zubkov, Leonid A; Lewin, Peter A

    2012-09-01

    This paper describes optimization of un-tethered, low voltage, 20-100kHz flexural transducers for biomedical ultrasonics applications. The goal of this work was to design a fully wearable, low weight (<100g), battery operated, piezoelectric ultrasound applicator providing maximum output pressure amplitude at the minimum excitation voltage. Such implementation of ultrasound applicators that can operate at the excitation voltages on the order of only 10-25V is needed in view of the emerging evidence that spatial-peak temporal-peak ultrasound intensity (I(SPTP)) on the order of 100mW/cm(2) delivered at frequencies below 100kHz can have beneficial therapeutic effects. The beneficial therapeutic applications include wound management of chronic ulcers and non-invasive transdermal delivery of insulin and liposome encapsulated drugs. The early prototypes of the 20 and 100kHz applicators were optimized using the maximum electrical power transfer theorem, which required a punctilious analysis of the complex impedance of the piezoelectric disks mounted in appropriately shaped metal housings. In the implementation tested, the optimized ultrasound transducer applicators were driven by portable, customized electronics, which controlled the excitation voltage amplitude and facilitated operation in continuous wave (CW) or pulsed mode with adjustable (10-90%) duty cycle. The driver unit was powered by remotely located rechargeable lithium (Li) polymer batteries. This was done to further minimize the weight of the applicator unit making it wearable. With DC voltage of approximately 15V the prototypes were capable of delivering pressure amplitudes of about 55kPa or 100mW/cm(2) (I(SPTP)). This level of acoustic output was chosen as it is considered safe and side effects free, even at prolonged exposure. PMID:22513259

  19. Optimization of un-tethered, low voltage, 20100 kHz flexural transducers for biomedical ultrasonics applications

    PubMed Central

    Sunny, Youhan; Bawiec, Christopher R.; Nguyen, An T.; Samuels, Joshua A.; Weingarten, Michael S.; Zubkov, Leonid A.; Lewin, Peter A.

    2012-01-01

    This paper describes optimization of un-tethered, low voltage, 20100 kHz flexural transducers for biomedical ultrasonics applications. The goal of this work was to design a fully wearable, low weight (<100 g), battery operated, piezoelectric ultrasound applicator providing maximum output pressure amplitude at the minimum excitation voltage. Such implementation of ultrasound applicators that can operate at the excitation voltages on the order of only 10–25 V is needed in view of the emerging evidence that spatial-peak temporal-peak ultrasound intensity (ISPTP) on the order of 100 mW/cm2 delivered at frequencies below 100 kHz can have beneficial therapeutic effects. The beneficial therapeutic applications include wound management of chronic ulcers and non-invasive transdermal delivery of insulin and liposome encapsulated drugs. The early prototypes of the 20 and 100 kHz applicators were optimized using the maximum electrical power transfer theorem, which required a punctilious analysis of the complex impedance of the piezoelectric disks mounted in appropriately shaped metal housings. In the implementation tested, the optimized ultrasound transducer applicators were driven by portable, customized electronics, which controlled the excitation voltage amplitude and facilitated operation in continuous wave (CW) or pulsed mode with adjustable (10–90%) duty cycle. The driver unit was powered by remotely located rechargeable lithium (Li) polymer batteries. This was done to further minimize the weight of the applicator unit making it wearable. With DC voltage of approximately 15 V the prototypes were capable of delivering pressure amplitudes of about 55 kPa or 100 mW/cm2 (ISPTP). This level of acoustic output was chosen as it is considered safe and side effects free, even at prolonged exposure. PMID:22513259

  20. The secular evolution of the Kuiper belt after a close stellar encounter

    NASA Astrophysics Data System (ADS)

    Punzo, D.; Capuzzo-Dolcetta, R.; Portegies Zwart, S.

    2014-11-01

    We show the effects of the perturbation caused by a passing by star on the Kuiper belt objects (KBOs) of our Solar system. The dynamics of the Kuiper belt (KB) is followed by direct N-body simulations. The sampling of the KB has been done with N up to 131 062, setting the KBOs on initially nearly circular orbits distributed in a ring of surface density Σ ˜ r-2. This modellization allowed us to investigate the secular evolution of the KB upon the encounter with the perturbing star. Actually, the encounter itself usually leads towards eccentricity and inclination distributions similar to observed ones, but tends also to excite the low-eccentricity population (e ≲ 0.1 around a ˜ 40 au from the Sun), depleting this region of low eccentricities. The following long-term evolution shows a `cooling' of the eccentricities repopulating the low-eccentricity area. In dependence on the assumed KBO mass spectrum and sampled number of bodies, this repopulation takes place in a time that goes from 0.5 to 100 Myr. Due to the unavoidable limitation in the number of objects in our long-term simulations (N ≤ 16 384), we could not consider a detailed KBO mass spectrum, accounting for low-mass objects, thus our present simulations are not reliable in constraining correlations among inclination distribution of the KBOs and other properties, such as their size distribution. However, our high-precision long-term simulations are a starting point for future larger studies on massively parallel computational platforms which will provide a deeper investigation of the secular evolution (˜100 Myr) of the KB over its whole mass spectrum.

  1. Temperature dependence of magnetoelastic properties of Fe100−xSix (5 < x < 20)

    SciTech Connect

    Petculescu, G.; Lambert, P.K.; Clark, A.E.; Hathaway, K.B.; Xing, Qingfeng; Lograsso, Tom; Restorff, J.B.; Wun-Fogle, M.

    2012-02-29

    Tetragonal magnetostriction (λγ,2) and elastic constants (c′, c44, and c11) for Fe100−xSix were measured as a function of temperature (T). Compositions corresponding to the disordered A2 (x = 5), ordered D03 (x = 19.8), and mixed (x = 11.6) phases, were investigated. The magnetoelastic coupling (−b1) was determined for 77 < T < 300 K and compared with those of Fe-Ga, Fe-Ge, and Fe-Al. Both λγ,2(T) and −b1(T) of Fe-Si behave similarly to those of Fe-Ge, while other notable differences exist between the measured properties of Fe-Si and those of the other three alloys. Due to the early establishment of short range order, Fe-Si exhibits a positive, although small, slope in λγ,2(T) at 5 at. % Si, and a remarkable drop in −b1 before the solubility limit. The weaker softening of the tetragonal shear modulus with the addition of Si and the lack of strong anharmonic effects in the Fe-Si lattice inferred from the weak T-dependence of all the moduli suggest that Fe-Si exhibits more structural stability than the other three alloys. The distinctive behavior is likely due to the smaller size of Si compared to the sizes of Ga, Ge and Al, and therefore to the effect of the larger size difference between Fe and Si in the Fe-Si lattice.

  2. THE SIZE, DENSITY, AND FORMATION OF THE ORCUS-VANTH SYSTEM IN THE KUIPER BELT

    SciTech Connect

    Brown, M. E.; Ragozzine, D.; Fraser, W. C.; Stansberry, J.

    2010-06-15

    The Kuiper Belt object (KBO) Orcus and its satellite Vanth form an unusual system in the Kuiper Belt. While most large KBOs have small satellites in circular orbits and smaller KBOs and their satellites tend to be much closer in size, Orcus sits in between these two regimes. Orcus is among the largest objects known in the Kuiper Belt, but the relative size of Vanth is much larger than that of the tiny satellites of the other large objects. Here, we characterize the physical and orbital characteristics of the Orcus-Vanth system in an attempt to distinguish discuss possible formation scenarios. From Hubble Space Telescope observations, we find that Orcus and Vanth have different visible colors and that Vanth does not share the water ice absorption feature seen in the infrared spectrum of Orcus. We also find that Vanth has a nearly face-on circular orbit with a period of 9.5393 {+-} 0.0001 days and semimajor axis of 8980 {+-} 20 km, implying a system mass of (6.32 {+-} 0.01) x 10{sup 20} kg or 3.8% the mass of dwarf planet Eris. From Spitzer Space Telescope observations, we find that the thermal emission is consistent with a single body with diameter 940 {+-} 70 km and a geometric albedo of 0.28 {+-} 0.04. Assuming equal densities and albedos, this measurement implies sizes of Orcus and Vanth of 900 and 280 km, respectively, and a mass ratio of 33. Assuming a factor of 2 lower albedo for the non-icy Vanth, however, implies sizes of 860 km and 380 km and a mass ratio of 12. The measured density depends on the assumed albedo ratio of the two objects but is approximately 1.5 {+-} 0.3 g cm{sup -3}, midway between typical densities measured for larger and smaller objects. The orbit and mass ratio is consistent with formation from a giant impact and subsequent outward tidal evolution, and even consistent with the system having now achieved a double synchronous state. Because of the large angle between the plane of the heliocentric orbit of Orcus and the plane of the orbit

  3. Searching for Chips of Kuiper Belt Objects in Meteorites

    NASA Technical Reports Server (NTRS)

    Zolensky, M. E.; Ohsumi, K.; Briani, G.; Gounelle, M.; Mikouchi, T.; Satake, W.; Kurihara, T.; Weisberg, M. K.; Le, L.

    2009-01-01

    The Nice model [1&2] describes a scenario whereby the Jovian planets experienced a violent reshuffling event approx.3:9 Ga the giant planets moved, existing small body reservoirs were depleted or eliminated, and new reservoirs were created in particular locations. The Nice model quantitatively explains the orbits of the Jovian planets and Neptune [1], the orbits of bodies in several different small body reservoirs in the outer solar system (e.g., Trojans of Jupiter [2], the Kuiper belt and scattered disk [3], the irregular satellites of the giant planets [4], and the late heavy bombardment on the terrestrial planets approx.3:9 Ga [5]. This model is unique in plausibly explaining all of these phenomena. One issue with the Nice model is that it predicts that transported Kuiper Belt Objects (KBOs) (things looking like D class asteroids) should predominate in the outer asteroid belt, but we know only about 10% of the objects in the outer main asteroid belt appear to be D-class objects [6]. However based upon collisional modeling, Bottke et al. [6] argue that more than 90% of the objects captured in the outer main belt could have been eliminated by impacts if they had been weakly-indurated objects. These disrupted objects should have left behind pieces in the ancient regoliths of other, presumably stronger asteroids. Thus, a derived prediction of the Nice model is that ancient regolith samples (regolith-bearing meteorites) should contain fragments of collisionally-destroyed Kuiper belt objects. In fact KBO pieces might be expected to be present in most ancient regolith- bearing meteorites [7&8].

  4. Beyond the Kuiper Belt Edge: New High Perihelion Trans-Neptunian Objects with Moderate Semimajor Axes and Eccentricities

    NASA Astrophysics Data System (ADS)

    Sheppard, Scott S.; Trujillo, Chadwick; Tholen, David J.

    2016-07-01

    We are conducting a survey for distant solar system objects beyond the Kuiper Belt edge (∼50 au) with new wide-field cameras on the Subaru and CTIO telescopes. We are interested in the orbits of objects that are decoupled from the giant planet region to understand the structure of the outer solar system, including whether a massive planet exists beyond a few hundred astronomical units as first reported in 2014 by Trujillo & Sheppard. In addition to discovering extreme trans-Neptunian objects detailed elsewhere, we found several objects with high perihelia (q > 40 au) that differ from the extreme and inner Oort cloud objects due to their moderate semimajor axes (50 < a < 100 au) and eccentricities (e ≲ 0.3). Newly discovered objects 2014 FZ71 and 2015 FJ345 have the third and fourth highest perihelia known after Sedna and 2012 VP113, yet their orbits are not nearly as eccentric or distant. We found several of these high-perihelion but moderate orbit objects and observe that they are mostly near Neptune mean motion resonances (MMRs) and have significant inclinations (i > 20°). These moderate objects likely obtained their unusual orbits through combined interactions with Neptune’s MMRs and the Kozai resonance, similar to the origin scenarios for 2004 XR190. We also find the distant 2008 ST291 has likely been modified by the MMR+KR mechanism through the 6:1 Neptune resonance. We discuss these moderately eccentric distant objects along with some other interesting low inclination outer classical belt objects like 2012 FH84 discovered in our ongoing survey.

  5. Beyond the Kuiper Belt Edge: New High Perihelion Trans-Neptunian Objects with Moderate Semimajor Axes and Eccentricities

    NASA Astrophysics Data System (ADS)

    Sheppard, Scott S.; Trujillo, Chadwick; Tholen, David J.

    2016-07-01

    We are conducting a survey for distant solar system objects beyond the Kuiper Belt edge (˜50 au) with new wide-field cameras on the Subaru and CTIO telescopes. We are interested in the orbits of objects that are decoupled from the giant planet region to understand the structure of the outer solar system, including whether a massive planet exists beyond a few hundred astronomical units as first reported in 2014 by Trujillo & Sheppard. In addition to discovering extreme trans-Neptunian objects detailed elsewhere, we found several objects with high perihelia (q > 40 au) that differ from the extreme and inner Oort cloud objects due to their moderate semimajor axes (50 < a < 100 au) and eccentricities (e ≲ 0.3). Newly discovered objects 2014 FZ71 and 2015 FJ345 have the third and fourth highest perihelia known after Sedna and 2012 VP113, yet their orbits are not nearly as eccentric or distant. We found several of these high-perihelion but moderate orbit objects and observe that they are mostly near Neptune mean motion resonances (MMRs) and have significant inclinations (i > 20°). These moderate objects likely obtained their unusual orbits through combined interactions with Neptune’s MMRs and the Kozai resonance, similar to the origin scenarios for 2004 XR190. We also find the distant 2008 ST291 has likely been modified by the MMR+KR mechanism through the 6:1 Neptune resonance. We discuss these moderately eccentric distant objects along with some other interesting low inclination outer classical belt objects like 2012 FH84 discovered in our ongoing survey.

  6. Analysis of Polarization Data from the Kuiper Airborne Observatory

    NASA Technical Reports Server (NTRS)

    Hildebrand, Roger H.

    1999-01-01

    The purpose of this grant was to complete the analysis of data obtained with the polarimeter, Hertz, on the Kuiper Airborne Observatory. This has enabled us to complete and publish two student theses (one on Sgr B2 and one on Orion) and a paper on the first results on the far-infrared polarization-spectrum. In addition it has enabled us to analyze data for two additional papers (one on W3 and the other a complete archive of KAO polarization data) which have reached the stage of complete drafts but still need checking and editing before final submission.

  7. 47 CFR 73.186 - Establishment of effective field at one kilometer.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... kilometer. 73.186 Section 73.186 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST... at one kilometer. (a) Section 73.189 provides that certain minimum field strengths are acceptable in... be made on six or more radials, at intervals of approximately 0.2 kilometer up to 3 kilometers...

  8. 47 CFR 73.186 - Establishment of effective field at one kilometer.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... kilometer. 73.186 Section 73.186 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST... at one kilometer. (a) Section 73.189 provides that certain minimum field strengths are acceptable in... be made on six or more radials, at intervals of approximately 0.2 kilometer up to 3 kilometers...

  9. 20-100 keV K(alpha) X-Ray Source Generation by Short Pulse High Intensity Lasers

    SciTech Connect

    Park, H-S; Koch, J A; Landen, O L; Phillips, T W; Goldsack, T

    2003-08-22

    We are studying the feasibility of utilizing K{alpha} x-ray sources in the range of 20 to 100 keV as a backlighters for imaging various stages of implosions and high areal density planar samples driven by the NIF laser facility. The hard x-ray K{alpha} sources are created by relativistic electron plasma interactions in the target material after a radiation by short pulse high intensity lasers. In order to understand K{alpha} source characteristics such as production efficiency and brightness as a function of laser parameters, we have performed experiments using the 10 J, 100 fs JanUSP laser. We utilized single-photon counting spectroscopy and x-ray imaging diagnostics to characterize the K{alpha} source. We find that the K{alpha} conversion efficiency from the laser energy is {approx} 3 x 10{sup -4}.

  10. Ultradeep (greater than 300 kilometers), ultramafic upper mantle xenoliths.

    PubMed

    Haggerty, S E; Sautter, V

    1990-05-25

    Geophysical discontinuities in Earth's upper mantle and experimental data predict the structural transformation of pyroxene to garnet and the solid-state dissolution of pyroxene into garnet with increasing depth. These predictions are indirectly verified by omphacitic pyroxene exsolution in pyropic garnet-bearing xenoliths from a diamondiferous kimberlite. Conditions for silicon in octahedral sites in the original garnets are met at pressures greater than 130 kilobars, placing the origin of these xenoliths at depths of 300 to 400 kilometers. These ultradeep xenoliths support the theory that the 400-km seismic discontinuity is marked by a transition from peridotite to eclogite. PMID:17745405

  11. First ultraviolet reflectance measurements of several Kuiper Belt objects, Kuiper Belt object satellites, and new ultraviolet measurements of A Centaur

    SciTech Connect

    Stern, S. A.; Schindhelm, E.; Cunningham, N. J.

    2014-05-01

    We observed the 2600-3200 Å (hereafter, mid-UV) reflectance of two Kuiper Belt Objects (KBOs), two KBO satellites, and a Centaur, using the Hubble Space Telescope (HST) Cosmic Origins Spectrograph (COS). Other than measurements of the Pluto system, these constitute the first UV measurements obtained of KBOs, and KBO satellites, and new HST UV measurements of the Centaur 2060 Chiron. We find significant differences among these objects, constrain the sizes and densities of Haumea's satellites, and report the detection of a possible spectral absorption band in Haumea's spectrum near 3050 Å. Comparisons of these objects to previously published UV reflectance measurements of Pluto and Charon are also made here.

  12. Forming the Cold Classical Kuiper Belt in a Light Disk

    NASA Astrophysics Data System (ADS)

    Shannon, Andrew; Wu, Yanqin; Lithwick, Yoram

    2016-02-01

    Large Kuiper Belt objects are conventionally thought to have formed out of a massive planetesimal belt that is a few thousand times its current mass. Such a picture, however, is incompatible with multiple lines of evidence. Here, we present a new model for the conglomeration of Cold Classical Kuiper Belt objects, out of a solid belt only a few times its current mass, or a few per cent of the solid density in a Minimum Mass Solar Nebula. This is made possible by depositing most of the primordial mass in grains of centimeter size or smaller. These grains collide frequently and maintain a dynamically cold belt out of which large bodies grow efficiently: an order-unity fraction of the solid mass can be converted into large bodies, in contrast to the ∼ {10}-3 efficiency in conventional models. Such a light belt may represent the true outer edge of the solar system, and it may have effectively halted the outward migration of Neptune. In addition to the high efficiency, our model can also produce a mass spectrum that peaks at an intermediate size, similar to the observed Cold Classicals, if one includes the effect of cratering collisions. In particular, the observed power-law break observed at ∼ 30 {km} for Cold Classicals, one that has been interpreted as a result of collisional erosion, may be primordial in origin.

  13. A collisional family of icy objects in the Kuiper belt.

    PubMed

    Brown, Michael E; Barkume, Kristina M; Ragozzine, Darin; Schaller, Emily L

    2007-03-15

    The small bodies in the Solar System are thought to have been highly affected by collisions and erosion. In the asteroid belt, direct evidence of the effects of large collisions can be seen in the existence of separate families of asteroids--a family consists of many asteroids with similar orbits and, frequently, similar surface properties, with each family being the remnant of a single catastrophic impact. In the region beyond Neptune, in contrast, no collisionally created families have hitherto been found. The third largest known Kuiper belt object, 2003 EL61, however, is thought to have experienced a giant impact that created its multiple satellite system, stripped away much of an overlying ice mantle, and left it with a rapid rotation. Here we report the discovery of a family of Kuiper belt objects with surface properties and orbits that are nearly identical to those of 2003 EL61. This family appears to be fragments of the ejected ice mantle of 2003 EL61. PMID:17361177

  14. Resonant and Secular Families of the Kuiper Belt

    NASA Astrophysics Data System (ADS)

    Chiang, E. I.; Lovering, J. R.; Millis, R. L.; Buie, M. W.; Wasserman, L. H.; Meech, K. J.

    2003-06-01

    We review ongoing efforts to identify occupants of mean-motion resonances (MMRs) and collisional families in the Edgeworth-Kuiper belt. Direct integrations of trajectories of Kuiper belt objects (KBOs) reveal the 1:1 (Trojan), 5:4, 4:3, 3:2 (Plutino), 5:3, 7:4, 9:5, 2:1 (Twotino), and 5:2 MMRs to be inhabited. Apart from the Trojan, resonant KBOs typically have large orbital eccentricities and inclinations. The observed pattern of resonance occupation is consistent with resonant capture and adiabatic excitation by a migratory Neptune; however, the dynamically cold initial conditions prior to resonance sweeping that are typically assumed by migration simulations are probably inadequate. Given the dynamically hot residents of the 5:2 MMR and the substantial inclinations observed in all exterior MMRs, a fraction of the primordial belt was likely dynamically pre-heated prior to resonance sweeping. A pre-heated population may have arisen as Neptune gravitationally scattered objects into trans-Neptunian space. The spatial distribution of Twotinos offers a unique diagnostic of Neptune's migration history. The Neptunian Trojan population may rival the Jovian Trojan population, and the former's existence is argued to rule out violent orbital histories for Neptune. Finally, lowest-order secular theory is applied to several hundred non-resonant KBOs with well-measured orbits to update proposals of collisional families. No convincing family is detected.

  15. Insolation and Resulting Surface Temperatures of the Kuiper-Rudaki Study Region on Mercury.

    NASA Astrophysics Data System (ADS)

    Bauch, Karin E.; Hiesinger, Harald; D'Amore, Mario; Helbert, Jörn; Weinauer, Julia

    2016-04-01

    cold poles along the equator. The region shows smooth plains surrounding crater Rudaki (˜120km), as well as cratered terrain around the prominent crater Kuiper (˜60km) and has been extensively covered by measurements during the MESSENGER mission. Temperatures range from about 100K during the night to 570K (cold pole) and 700K (hot pole) at local noon. The floor of Kuiper crater reaches temperatures of ˜660K at local noon, while those at Rudaki crater are 625K (+/-5K). Due to their higher albedo, the rays of Kuiper crater are about 5K colder than the surrounding regions. These temperature estimates will aid the accurate interpretation of future MERTIS spectra of the region obtained during the BepiColombo mission [10]. References: [1] Hiesinger, H. et al. (2010), PSS 58, 144-165. [2] Helbert, J. et al. (2005), LPSC XXXVI, #1753. [3] Keihm, S.J. and Langseth, M.G. (1973), Proc. Lunar Sci. Conf. 4th, 2503-2513. [4] Lawson, S.L. et al. (2000), JGR 105, E5, 4273-4290. [5] Pieters, C.M. et al. (2009), Science 326, 568-572. [6] Paige, D.A. et al. (2010), Space Sci. Rev 150, 125-160. [7] Bauch, K.E. et al. (2014), PSS 101, 27-36. [8] Vasavada, A. et al. (1999), Icarus 141, 179-193. [9] Solomon, S.C. et al. (2008), Science 321, 59-62. [10] D'Amore et al. (2013), AGU, #P13A-1735.

  16. Finite element static displacement optimization of 20-100 kHz flexural transducers for fully portable ultrasound applicator.

    PubMed

    Bawiec, Christopher R; Sunny, Youhan; Nguyen, An T; Samuels, Joshua A; Weingarten, Michael S; Zubkov, Leonid A; Lewin, Peter A

    2013-02-01

    This paper focuses on the development of a finite-element model and subsequent stationary analysis performed to optimize individual flexural piezoelectric elements for operation in the frequency range of 20-100kHz. These elements form the basic building blocks of a viable, un-tethered, and portable ultrasound applicator that can produce intensities on the order of 100mW/cm(2) spatial-peak temporal-peak (I(SPTP)) with minimum (on the order of 15V) excitation voltage. The ultrasound applicator can be constructed with different numbers of individual transducer elements and different geometries such that its footprint or active area is adjustable. The primary motivation behind this research was to develop a tether-free, battery operated, fully portable ultrasound applicator for therapeutic applications such as wound healing and non-invasive transdermal delivery of both naked and encapsulated drugs. It is shown that careful selection of the components determining applicator architecture allows the displacement amplitude to be maximized for a specific frequency of operation. The work described here used the finite-element analysis software COMSOL to identify the geometry and material properties that permit the applicator's design to be optimized. By minimizing the excitation voltage required to achieve the desired output (100mW/cm(2)I(SPTP)) the power source (rechargeable Li-Polymer batteries) size may be reduced permitting both the electronics and ultrasound applicator to fit in a wearable housing. PMID:23040829

  17. Layered Model for Radiation-Induced Chemical Evolution of Icy Surface Composition and Dynamics on Kuiper Belt and Oort Cloud Bodies

    NASA Technical Reports Server (NTRS)

    Cooper, John F.; Richardson, John D.

    2010-01-01

    The diversity of albedos and surface colors on observed Kuiper Belt and Inner Oort Cloud objects remains to be explained in terms of competition between primordial intrinsic versus exogenic drivers of surface and near-surface evolution. Earlier models have attempted without success to attribute this diversity to the relations between surface radiolysis from cosmic ray irradiation and gardening by meteoritic impacts. A more flexible approach considers the different depth-dependent radiation profiles produced by low-energy plasma, suprathermal, and maximally penetrating charged particles of the heliospheric and local interstellar radiation environment. Generally red objects of the dynamically cold (low inclination, circular orbit) Classical Kuiper Belt might be accounted for from erosive effects of plasma ions and reddening effects of high energy cosmic ray ions, while suprathermal keV-MeV ions could alternatively produce more color neutral surfaces. The deepest layer of more pristine ice can be brought to the surface from meter to kilometer depths by larger impact events and potentially by cryovolcanic activity. The bright surfaces of some larger objects, e.g. Eris, suggest ongoing resurfacing activity. Cycles of atmospheric formation and surface freezeout can further account for temporal variation as observed on Pluto. The diversity of causative processes must therefore be understood to account for observationally apparent diversities of the object surfaces.

  18. The color-magnitude distribution of small Kuiper Belt objects

    NASA Astrophysics Data System (ADS)

    Wong, Ian; Brown, Michael E.

    2015-11-01

    Occupying a vast region beyond the ice giants is an extensive swarm of minor bodies known as the Kuiper Belt. Enigmatic in their formation, composition, and evolution, these Kuiper Belt objects (KBOs) lie at the intersection of many of the most important topics in planetary science. Improved instruments and large-scale surveys have revealed a complex dynamical picture of the Kuiper Belt. Meanwhile, photometric studies have indicated that small KBOs display a wide range of colors, which may reflect a chemically diverse initial accretion environment and provide important clues to constraining the surface compositions of these objects. Notably, some recent work has shown evidence for bimodality in the colors of non-cold classical KBOs, which would have major implications for the formation and subsequent evolution of the entire KBO population. However, these previous color measurements are few and mostly come from targeted observations of known objects. As a consequence, the effect of observational biases cannot be readily removed, preventing one from obtaining an accurate picture of the true color distribution of the KBOs as a whole.We carried out a survey of KBOs using the Hyper Suprime-Cam instrument on the 8.2-meter Subaru telescope. Our observing fields targeted regions away from the ecliptic plane so as to avoid contamination from cold classical KBOs. Each field was imaged in both the g’ and i’ filters, which allowed us to calculate the g’-i’ color of each detected object. We detected more than 500 KBOs over two nights of observation, with absolute magnitudes from H=6 to H=11. Our survey increases the number of KBOs fainter than H=8 with known colors by more than an order of magnitude. We find that the distribution of colors demonstrates a robust bimodality across the entire observed range of KBO sizes, from which we can categorize individual objects into two color sub-populations -- the red and very-red KBOs. We present the very first analysis of the

  19. Sub-kilometer Numerical Weather Prediction in complex urban areas

    NASA Astrophysics Data System (ADS)

    Leroyer, S.; Bélair, S.; Husain, S.; Vionnet, V.

    2013-12-01

    A Sub-kilometer atmospheric modeling system with grid-spacings of 2.5 km, 1 km and 250 m and including urban processes is currently being developed at the Meteorological Service of Canada (MSC) in order to provide more accurate weather forecasts at the city scale. Atmospheric lateral boundary conditions are provided with the 15-km Canadian Regional Deterministic Prediction System (RDPS). Surface physical processes are represented with the Town Energy Balance (TEB) model for the built-up covers and with the Interactions between the Surface, Biosphere, and Atmosphere (ISBA) land surface model for the natural covers. In this study, several research experiments over large metropolitan areas and using observational networks at the urban scale are presented, with a special emphasis on the representation of local atmospheric circulations and their impact on extreme weather forecasting. First, numerical simulations are performed over the Vancouver metropolitan area during a summertime Intense Observing Period (IOP of 14-15 August 2008) of the Environmental Prediction in Canadian Cities (EPiCC) observational network. The influence of the horizontal resolution on the fine-scale representation of the sea-breeze development over the city is highlighted (Leroyer et al., 2013). Then severe storms cases occurring in summertime within the Greater Toronto Area (GTA) are simulated. In view of supporting the 2015 PanAmerican and Para-Pan games to be hold in GTA, a dense observational network has been recently deployed over this region to support model evaluations at the urban and meso scales. In particular, simulations are conducted for the case of 8 July 2013 when exceptional rainfalls were recorded. Leroyer, S., S. Bélair, J. Mailhot, S.Z. Husain, 2013: Sub-kilometer Numerical Weather Prediction in an Urban Coastal Area: A case study over the Vancouver Metropolitan Area, submitted to Journal of Applied Meteorology and Climatology.

  20. 25-Hydroxyvitamin D in the Range of 20 to 100 ng/mL and Incidence of Kidney Stones

    PubMed Central

    Nguyen, Stacie; Baggerly, Leo; French, Christine; Heaney, Robert P.; Gorham, Edward D.

    2014-01-01

    Objectives. Increasing 25-hydroxyvitamin D serum levels can prevent a wide range of diseases. There is a concern about increasing kidney stone risk with vitamin D supplementation. We used GrassrootsHealth data to examine the relationship between vitamin D status and kidney stone incidence. Methods. The study included 2012 participants followed prospectively for a median of 19 months. Thirteen individuals self-reported kidney stones during the study period. Multivariate logistic regression was applied to assess the association between vitamin D status and kidney stones. Results. We found no statistically significant association between serum 25-hydroxyvitamin D and kidney stones (P = .42). Body mass index was significantly associated with kidney stone risk (odds ratio = 3.5; 95% confidence interval = 1.1, 11.3). Conclusions. We concluded that a serum 25-hydroxyvitamin D level of 20 to 100 nanograms per milliliter has no significant association with kidney stone incidence. PMID:24134366

  1. Testing of the Kuiper Airborne Observatory 91-CM telescope

    NASA Technical Reports Server (NTRS)

    Parks, R. E.

    1979-01-01

    The 91 cm telescope of the Kuiper Airborne Observatory was tested for optical figure errors in the surface of the mirrors and misalignment of the optical components. When the present set of optical components are installed in the telescope in proper alignment, the telescope produces an image with 80% of the energy in a circle of 1.50 arc seconds in diameter; that is, a 0.11 mm spot diameter in the focal plane. The primary mirror, an f/2 parabola, was tested against a flat and has a quality that puts 80% of the energy in a 0.51 arc second diameter spot. Two principal sources account for the residual error: the tertiary folding flat and the chopping secondary. It appears that the method of mounting the folding flat causes some distortion and that the secondary mirror has some residual spherical aberration in its figure.

  2. Explaining the Kuiper Belt with a Jumping Planet

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2015-09-01

    A feature of the Kuiper Belt known as the kernel has yet to be adequately explained by solar system formation models. In a recent study, a theorist at the Southwest Research Institute proposes a new explanation for how Neptune arrived at its current orbit and how this planets migration in the early years of the solar system might have created the kernel.Orbital JumpThe kernel is a concentration of orbits within the Kuiper Belt that all have semimajor axes of roughly a 44 AU, low eccentricities, and low inclinations. How this collection of objects formed and why they exist where they do is difficult to explain with current models, however. Kernel objects arent in resonance with any of the larger bodies, so why are they concentrated at that specific distance? In this study, David Nesvorn proposes that the kernel resulted from Neptunes outward migration through the solar system.In the currently favored model of our solar systems formation, the outermost gas giant planets formed closer to the Sun and then migrated out to their current locations. Nesvorn ran a series of simulations of this migration to test the theory that a discontinuity in Neptunes movement outward i.e., a sudden jump in the planets orbital distance could explain the presence of the Kuiper Belts kernel.Results from a previous study, in which the authors evolved the four gas giant planets plus a fifth giant planet (blue) initially on an orbit between Saturn and Uranus. At 18.3 Myr, a close encounter with the fifth planet causes Neptunes orbit (pink) to jump outwards by ~0.4 AU, and the fifth planet is then ejected from the solar system by Jupiter. [Nesvorn 2015]Resonant PopulationNesvorn was successful in finding a model that reproduced the kernel, as well as other observed features of the solar system today. In his model, Neptune began its journey closer to the Sun, at a distance of roughly 24 AU, and it migrated fairly rapidly outward to about 28 AU. As it traveled, it swept up bodies in the outer

  3. Pluto/Kuiper Missions with Advanced Electric Propulsion and Power

    NASA Technical Reports Server (NTRS)

    Oleson, S. R.; Patterson, M. J.; Schrieber, J.; Gefert, L. P.

    2001-01-01

    In response to a request by NASA Code SD Deep Space Exploration Technology Program, NASA Glenn Research center performed a study to identify advanced technology options to perform a Pluto/Kuiper mission without depending on a 2004 Jupiter Gravity Assist, but still arriving before 2020. A concept using a direct trajectory with small, sub-kilowatt ion thrusters and Stirling radioisotope power system was shown to allow the same or smaller launch vehicle class (EELV) as the chemical 2004 baseline and allow launch in any year and arrival in the 2014 to 2020 timeframe. With the nearly constant power available from the radioisotope power source such small ion propelled spacecraft could explore many of the outer planetary targets. Such studies are already underway. Additional information is contained in the original extended abstract.

  4. Microlensing by Kuiper, Oort, and Free-Floating Planets

    NASA Astrophysics Data System (ADS)

    Gould, Andrew

    2016-08-01

    Microlensing is generally thought to probe planetary systems only out to a few Einstein radii. Microlensing events generated by bound planets beyond about 10 Einstein radii generally do not yield any trace of their hosts, and so would be classified as free floating planets (FFPs). I show that it is already possible, using adaptive optics (AO), to constrain the presence of potential hosts to FFP candidates at separations comparable to the Oort Cloud. With next-generation telescopes, planets at Kuiper-Belt separations can be probed. Next generation telescopes will also permit routine vetting for all FFP candidates, simply by obtaining second epochs 4-8 years after the event.At present, the search for such hosts is restricted to within the ``confusion limit'' of θ_\\confus ˜ 0.25'' but future WFIRST (Wide Field Infrared Survey Telescope) observations will allow one to probe beyond this confusion limit as well.

  5. Formation of High Mass Hydrocarbons on Kuiper Belt Objects

    NASA Astrophysics Data System (ADS)

    Jones, Brant M.; Bennett, C.; Gu, X.; Kaiser, R.

    2012-10-01

    We present recent results from the newly established W.M. Keck Research Laboratory in Astrochemistry regarding the formation of high molecular weight ( C15) hydrocarbons starting from pure, simple hydrocarbons ices upon interaction of these ices with ionizing radiation: methane (CH4), ethane (C2H6), propane (C3H8) and n-butane (C4H10). Specifically, we have utilized a novel application of reflection time-of-flight mass spectrometry coupled with soft vacuum ultraviolet photoionization to observe the nature of high mass hydro- carbons as a function of their respective sublimation temperature. The Kuiper Belt is estimated to consist of over 70,000 icy bodies, which extend beyond the orbit of Neptune at 30 AU. These bodies are thought to have maintained low temperatures (30-50 K) since the formation of the solar system and are regarded as frozen relics that may preserve a record of the primitive volatiles from which the solar system formed. In particular, methane has been detected on the surfaces of Sedna, Quaoar, Triton (thought to be a captured KBO) and Pluto along with ethane being tentatively assigned to on Quaoar, Pluto, and Orcus. The surfaces of these bodies have undergone 4.5 Gyr of chemical processing due to ionizing radiation from the solar wind and Galactic Cosmic Radiation. Our research has been focused on trying to understand how these ices have evolved over the age of our solar system by simulating the chemical processing via ionizing radiation in an ultrahigh vacuum chamber coupled with a variety of optical analytical spectroscopies (FT-IR, Raman, UV-Vis) and gas phase mass spectroscopy. Our results indicate that larger, more complex hydrocarbons up to C15 are formed easily under conditions relevant to the environment of Kuiper Belt Objects which may help elucidate part of the puzzle regarding the ‘colors’ of these objects along with the formation of carbonaceous material throughout the interstellar medium.

  6. TAOS: Taiwan-American Occultation Survey of Comet-Sized Objects in the Kuiper Belt

    NASA Technical Reports Server (NTRS)

    Lissauer, Jack; DeVincenzi, Donald (Technical Monitor)

    1999-01-01

    Several dozen minor planets with radii greater than 100 km have been detected beyond Neptune using large telescopes. The TAOS project is to measure directly the number of these KBOs (Kuiper Belt Objects) down to the typical size of cometary nuclei (a few km) and out as far as approximately 100 AU from the Sun. Because of their large distance, small sizes and presumed low albedos, these target objects are extremely faint. Three 50 cm wide field robotic telescopes with 2048 x 2048 CCD cameras will be deployed along a 7 km east-west baseline in or near Jade Mountain National Park in Taiwan. They will monitor approximately 3000 stars for occultations by KBOs in a coincidence mode, so that the sequence and timing of the three separate blinkings can be used to distinguish real events from false alarms. Follow-up imaging observations using large telescopes will yield albedos and orbits for some of the larger objects detected by TAOS. A fourth telescope on a north-south spur to refine the size information on occulting GABON is also being contemplated.

  7. The formation of the Kuiper belt by the outward transport of bodies during Neptune's migration.

    PubMed

    Levison, Harold F; Morbidelli, Alessandro

    2003-11-27

    The 'dynamically cold Kuiper belt' consists of objects on low-inclination orbits between approximately 40 and approximately 50 au from the Sun. It currently contains material totalling less than a tenth the mass of the Earth, which is surprisingly low because, according to accretion models, the objects would not have grown to their present size unless the cold Kuiper belt originally contained tens of Earth masses of solids. Although several mechanisms have been proposed to produce the observed mass depletion, they all have significant limitations. Here we show that the objects currently observed in the dynamically cold Kuiper belt were most probably formed within approximately 35 au and were subsequently pushed outward by Neptune's 1:2 mean motion resonance during its final phase of migration. Combining our mechanism with previous work, we conclude that the entire Kuiper belt formed closer to the Sun and was transported outward during the final stages of planet formation. PMID:14647375

  8. The Square Kilometer Array and The Cradle of Life

    NASA Astrophysics Data System (ADS)

    Lazio, T. J. W.; Tarter, J. C.; Werthimer, D.; Wilner, D. J.

    2005-12-01

    The Square Kilometer Array (SKA) will be one of a suite of new, large telescopes for the Twenty-first Century probing fundamental physics, the origin and evolution of the Universe, the structure of the Milky Way Galaxy, and the formation and distribution of planets. The emerging field of astrobiology is beginning to address one of the oldest questions in science and philosophy: Are we alone? By virtue of its sheer sensitivity, high frequency coverage, and long baselines, the SKA will play a pivotal role in astrobiological studies. It will be a unique instrument with the capability to image proto-planetary disks in nearby star-forming regions and monitor the evolution of structures within those disks (``movies of planetary formation''). It will be able to reach qualitatively new levels of sensitivity in the search for intelligence elsewhere in the Galaxy, including for the first time the realistic possibility of detecting unintentional emissions or ``leakage'' (such as from TV transmitters) from nearby stars. Finally, it will also be able to assess the extent to which interstellar molecules are incorporated into proto-planetary disks. Basic research in radio astronomy at the NRL is supported by the Office of Naval Research.

  9. The Allen Telescope Array as Square Kilometer Array Pathfinder

    NASA Astrophysics Data System (ADS)

    Bower, Geoffrey C.

    2007-12-01

    The Allen Telescope Array (ATA) is a new radio interferometer that has begun scientific operations in 2007. Many of the technologies, techniques, and observing modes developed for the ATA are directly applicable to the Square Kilometer Array (SKA). The ATA is a pioneer of the LNSD, which refers to a large number (LN) of small diameter (SD) dishes to create the array. This concept underlies nearly all SKA designs. Other relevant technologies are the offset Gregorian ATA antenna, the ATA wideband log periodic feed, transport of broadband data over fiber optic cables, and flexible digital signal processing electronics. The small dishes of the ATA gives it extraordinary wide-field imaging and survey capability but also require new solutions for calibration and imaging. Real time imaging, rapid response to transients, and thinking telescope technology are also under development. Finally, the ATA is developing commensal observing modes, which enable multiple simultaneous science programs, such as SETI, transient surveys, and HI surveys. Opportunities exist for community members to perform scientific investigations as well as develop techniques and technology for the SKA through use of the ATA.

  10. Imaging protoplanetary disks with a square kilometer array

    NASA Astrophysics Data System (ADS)

    Wilner, D. J.

    2004-12-01

    The recent detections of extrasolar giant planets has revealed a surprising diversity of planetary system architectures, with many very unlike our Solar System. Understanding the origin of this diversity requires multi-wavelength studies of the structure and evolution of the protoplanetary disks that surround young stars. Radio astronomy and the square kilometer array (SKA) will play a unique role in these studies by imaging thermal dust emission in a representative sample of protoplanetary disks at unprecedented sub-AU scales in the innermost regions, including the "habitable zone" that lies within a few AU of the central stars. Radio observations will probe the evolution of dust grains up to centimeter-sized "pebbles", the critical first step in assembling giant planet cores and terrestrial planets, through the wavelength dependence of dust emissivity, which provides a diagnostic of particle size. High resolution images of dust emission will show directly mass concentrations and features in disk surface density related to planet building, in particular the radial gaps opened by tidal interactions between planets and disks, and spiral waves driven by embedded protoplanets. Moreover, because orbital timescales are short in the inner disk, synoptic studies over months and years will show proper motions and allow for the tracking of secular changes in disk structure. SKA imaging of protoplanetary disks will reach into the realm of rocky planets for the first time, and they will help clarify the effects of the formation of giant planets on their terrestrial counterparts.

  11. 20 CFR 1002.100 - Does the five-year service limit include all absences from an employment position that are...

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false Does the five-year service limit include all absences from an employment position that are related to service in the uniformed services? 1002.100 Section 1002.100 Employees' Benefits OFFICE OF THE ASSISTANT SECRETARY FOR VETERANS' EMPLOYMENT AND TRAINING SERVICE, DEPARTMENT OF LABOR...

  12. Structure and Evolution of Kuiper Belt Objects and Dwarf Planets

    NASA Astrophysics Data System (ADS)

    McKinnon, W. B.; Prialnik, D.; Stern, S. A.; Coradini, A.

    Kuiper belt objects (KBOs) accreted from a mélange of volatile ices, carbonaceous matter, and rock of mixed interstellar and solar nebular provenance. The transneptunian region, where this accretion took place, was likely more radially compact than today. This and the influence of gas drag during the solar nebula epoch argue for more rapid KBO accretion than usually considered. Early evolution of KBOs was largely the result of heating due to radioactive decay, the most important potential source being 26Al, whereas long-term evolution of large bodies is controlled by the decay of U, Th, and 40K. Several studies are reviewed dealing with the evolution of KBO models, calculated by means of one-dimensional numerical codes that solve the heat and mass balance equations. It is shown that, depending on parameters (principally rock content and porous conductivity), KBO interiors may have reached relatively high temperatures. The models suggest that KBOs likely lost ices of very volatile species during early evolution, whereas ices of less-volatile species should be retained in cold, less-altered subsurface layers. Initially amorphous ice may have crystallized in KBO interiors, releasing volatiles trapped in the amorphous ice, and some objects may have lost part of these volatiles as well. Generally, the outer layers are far less affected by internal evolution than the inner part, which in the absence of other effects (such as collisions) predicts a stratified composition and altered porosity distribution. Kuiper belt objects are thus unlikely to be "the most pristine objects in the solar system," but they do contain key information as to how the early solar system accreted and dynamically evolved. For large (dwarf planet) KBOs, long-term radiogenic heating alone may lead to differentiated structures -- rock cores, ice mantles, volatile-ice-rich "crusts," and even oceans. Persistence of oceans and (potential) volcanism to the present day depends strongly on body size and

  13. Formation of High Mass Hydrocarbons on Kuiper Belt Objects

    NASA Astrophysics Data System (ADS)

    Jones, B. M.; Bennett, C.; Gu, X.; Kaiser, R. I.

    2012-12-01

    Recent results from the newly established W.M. Keck Research Laboratory in Astrochemistry are presented regarding the formation of high molecular weight (~ C15) hydrocarbons starting from pure, simple saturated hydrocarbons ices: methane (CH4), ethane (C2H6), propane (C3H8) and n-butane (C4H10) upon the interaction of these ices with ionizing radiation. Specifically, we have utilized a novel application of reflection time-of-flight mass spectrometry coupled with soft vacuum ultraviolet photoionization to observe the sublimation of the high mass hydrocarbons as a function of temperature. The Kuiper Belt is estimated to consist of over 70,000 icy bodies, which extend beyond the orbit of Neptune at 30 AU. These bodies are believed to have maintained low temperatures (30-50 K) since the formation of the solar system and are often regarded as frozen relics that may preserve a record of the primitive volatiles from which the solar system formed. In particular, methane has been detected on the surfaces of Sedna, Quaoar, Triton (thought to be a captured KBO) and Pluto along with ethane being tentatively assigned to on Quaoar, Pluto, and Orcus. Throughout the past 4.5 billion years, these surfaces have undergone significant chemical processing due to the barrage of ionizing radiation from solar wind and background Galactic Cosmic Rays. The main focus of our research has been elucidating how the outer planetary icy bodies have evolved over the age of the solar system by simulating the chemical changes induced from ionizing radiation in an ultrahigh vacuum chamber. These changes are monitored with a variety of optical analytical spectroscopies (FT-IR, Raman, UV-Vis) and gas phase mass spectroscopy coupled with soft vacuum ultraviolet photoionization of the subliming products at 10.5 eV. Our results indicate that larger, more complex hydrocarbons up to C15 are formed easily under conditions relevant to the environment of Kuiper Belt Objects which may help elucidate part of the

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

    PubMed Central

    Johansen, Anders; Low, Mordecai-Mark Mac; Lacerda, Pedro; Bizzarro, Martin

    2015-01-01

    Chondrules are millimeter-sized spherules that dominate primitive meteorites (chondrites) originating from the asteroid belt. The incorporation of chondrules into asteroidal bodies must be an important step in planet formation, but the mechanism is not understood. We show that the main growth of asteroids can result from gas drag–assisted accretion of chondrules. The largest planetesimals of a population with a characteristic radius of 100 km undergo runaway accretion of chondrules within ~3 My, forming planetary embryos up to Mars’s size along with smaller asteroids whose size distribution matches that of main belt asteroids. The aerodynamical accretion leads to size sorting of chondrules consistent with chondrites. Accretion of millimeter-sized chondrules and ice particles drives the growth of planetesimals beyond the ice line as well, but the growth time increases above the disc lifetime outside of 25 AU. The contribution of direct planetesimal accretion to the growth of both asteroids and Kuiper belt objects is minor. In contrast, planetesimal accretion and chondrule accretion play more equal roles in the formation of Moon-sized embryos in the terrestrial planet formation region. These embryos are isolated from each other and accrete planetesimals only at a low rate. However, the continued accretion of chondrules destabilizes the oligarchic configuration and leads to the formation of Mars-sized embryos and terrestrial planets by a combination of direct chondrule accretion and giant impacts. PMID:26601169

  15. Nature or nurture of coplanar Tatooines: the aligned circumbinary Kuiper belt analogue around HD 131511

    NASA Astrophysics Data System (ADS)

    Kennedy, Grant M.

    2015-02-01

    A key discovery of the Kepler mission is of the circumbinary planets known as `Tatooines', which appear to be well aligned with their host stars' orbits. Whether this alignment is due to initially coplanar circumbinary planet-forming discs (i.e. nature), or subsequent alignment of initially misaligned discs by warping the inner disc or torquing the binary (i.e. nurture), is not known. Tests of which scenario dominates may be possible by observing circumbinary Kuiper belt analogues (`debris discs'), which trace the plane of the primordial disc. Here, the 140 au diameter circumbinary debris disc around HD 131511 is shown to be aligned to within 10° of the plane of the near edge-on 0.2 au binary orbit. The stellar equator is also consistent with being in this plane. If the primordial disc was massive enough to pull the binary into alignment, this outcome should be common and distinguishing nature versus nurture will be difficult. However, if only the inner disc becomes aligned with the binary, the HD 131511 system was never significantly misaligned. Given an initial misalignment, the ˜ Gyr main-sequence lifetime of the star allows secular perturbations to align the debris disc out to 100 au at the cost of an increased scaleheight. The observed debris disc scaleheight limits any misalignment to less than 25°. With only a handful known, many more such systems need to be characterized to help test whether the alignment of circumbinary planets is nature or nurture.

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

    PubMed

    Johansen, Anders; Low, Mordecai-Mark Mac; Lacerda, Pedro; Bizzarro, Martin

    2015-04-01

    Chondrules are millimeter-sized spherules that dominate primitive meteorites (chondrites) originating from the asteroid belt. The incorporation of chondrules into asteroidal bodies must be an important step in planet formation, but the mechanism is not understood. We show that the main growth of asteroids can result from gas drag-assisted accretion of chondrules. The largest planetesimals of a population with a characteristic radius of 100 km undergo runaway accretion of chondrules within ~3 My, forming planetary embryos up to Mars's size along with smaller asteroids whose size distribution matches that of main belt asteroids. The aerodynamical accretion leads to size sorting of chondrules consistent with chondrites. Accretion of millimeter-sized chondrules and ice particles drives the growth of planetesimals beyond the ice line as well, but the growth time increases above the disc lifetime outside of 25 AU. The contribution of direct planetesimal accretion to the growth of both asteroids and Kuiper belt objects is minor. In contrast, planetesimal accretion and chondrule accretion play more equal roles in the formation of Moon-sized embryos in the terrestrial planet formation region. These embryos are isolated from each other and accrete planetesimals only at a low rate. However, the continued accretion of chondrules destabilizes the oligarchic configuration and leads to the formation of Mars-sized embryos and terrestrial planets by a combination of direct chondrule accretion and giant impacts. PMID:26601169

  17. Volatile Loss and Classification of Kuiper Belt Objects

    NASA Astrophysics Data System (ADS)

    Johnson, R. E.; Oza, A.; Young, L. A.; Volkov, A. N.; Schmidt, C.

    2015-08-01

    Observations indicate that some of the largest Kuiper Belt Objects (KBOs) have retained volatiles in the gas phase (e.g., Pluto), while others have surface volatiles that might support a seasonal atmosphere (e.g., Eris). Since the presence of an atmosphere can affect their reflectance spectra and thermal balance, Schaller & Brown examined the role of volatile escape driven by solar heating of the surface. Guided by recent simulations, we estimate the loss of primordial N2 for several large KBOs, accounting for escape driven by UV/EUV heating of the upper atmosphere as well as by solar heating of the surface. For the latter we present new simulations and for the former we scale recent detailed simulations of escape from Pluto using the energy limited escape model validated recently by molecular kinetic simulations. Unlike what has been assumed to date, we show that unless the N2 atmosphere is thin (<˜1018 N2 cm-2) and/or the radius small (<˜200-300 km), escape is primarily driven by the UV/EUV radiation absorbed in the upper atmosphere. This affects the discussion of the relationship between atmospheric loss and the observed surface properties for a number of the KBOs examined. Our long-term goal is to connect detailed atmospheric loss simulations with a model for volatile transport for individual KBOs.

  18. Collisional Grooming Models of the Kuiper Belt Dust Cloud

    NASA Technical Reports Server (NTRS)

    Kuchner, Marc J.; Stark, Christopher C.

    2010-01-01

    We modeled the three-dimensional structure of the Kuiper Belt (KB) dust cloud at four different dust production rates, incorporating both planet-dust interactions and grain-grain collisions using the collisional grooming algorithm. Simulated images of a model with a face-on optical depth of approximately 10 (exp -4) primarily show an azimuthally- symmetric ring at 40-47 AU in submillimeter and infrared wavelengths; this ring is associated with the cold classical KB. For models with lower optical depths (10 (exp -6) and 10 (exp-7)), synthetic infrared images show that the ring widens and a gap opens in the ring at the location of Neptune; this feature is caused by trapping of dust grains in Neptune's mean motion resonances. At low optical depths, a secondary ring also appears associated with the hole cleared in the center of the disk by Saturn. Our simulations, which incorporate 25 different grain sizes, illustrate that grain-grain collisions are important in sculpting today's KB dust, and probably other aspects of the solar system dust complex; collisions erase all signs of azimuthal asymmetry from the submillimeter image of the disk at every dust level we considered. The model images switch from being dominated by resonantly trapped small grains ("transport dominated") to being dominated by the birth ring ("collision dominated") when the optical depth reaches a critical value of r approximately v/c, where v is the local Keplerian speed.

  19. Dynamical implantation of objects in the Kuiper Belt

    SciTech Connect

    Brasil, P. I. O.

    2014-09-01

    Several models have been suggested in the past to describe the dynamical formation of hot Kuiper Belt objects (hereafter Hot Classicals or HCs for short). Here, we discuss a dynamical mechanism that allows orbits to evolve from the primordial planetesimal disk at ≲ 35 AU to reach the orbital region now occupied by HCs. We performed three different sets of numerical simulations to illustrate this mechanism. Two of these simulations were based on modern theories for the early evolution of the solar system (the Nice and jumping-Jupiter models). The third simulation was performed with the purpose of increasing the resolution at 41-46 AU. The common aspect of these simulations is that Neptune scatters planetesimals from ≲ 35 AU to >40 AU and then undergoes a long phase of slow residual migration. Our results show that to reach an HC orbit, a scattered planetesimal needs to be captured in a mean motion resonance (MMR) with Neptune where the perihelion distance rises due to the Kozai resonance (which occurs in MMRs even for moderate inclinations). Finally, while Neptune is still migrating, the planetesimal is released from the MMR on a stable HC orbit. We show that the orbital distribution of HCs expected from this process provides a reasonable match to observations. The capture efficiency and the mass deposited into the HC region appears to be sensitive to the maximum eccentricity reached by Neptune during the planetary instability phase. Additional work will be needed to resolve this dependency in detail.

  20. COLLISIONAL GROOMING MODELS OF THE KUIPER BELT DUST CLOUD

    SciTech Connect

    Kuchner, Marc J.; Stark, Christopher C. E-mail: starkc@umd.ed

    2010-10-15

    We modeled the three-dimensional structure of the Kuiper Belt (KB) dust cloud at four different dust production rates, incorporating both planet-dust interactions and grain-grain collisions using the collisional grooming algorithm. Simulated images of a model with a face-on optical depth of {approx}10{sup -4} primarily show an azimuthally symmetric ring at 40-47 AU in submillimeter and infrared wavelengths; this ring is associated with the cold classical KB. For models with lower optical depths (10{sup -6} and 10{sup -7}), synthetic infrared images show that the ring widens and a gap opens in the ring at the location of Neptune; this feature is caused by trapping of dust grains in Neptune's mean motion resonances. At low optical depths, a secondary ring also appears associated with the hole cleared in the center of the disk by Saturn. Our simulations, which incorporate 25 different grain sizes, illustrate that grain-grain collisions are important in sculpting today's KB dust, and probably other aspects of the solar system dust complex; collisions erase all signs of azimuthal asymmetry from the submillimeter image of the disk at every dust level we considered. The model images switch from being dominated by resonantly trapped small grains ('transport dominated') to being dominated by the birth ring ('collision dominated') when the optical depth reaches a critical value of {tau} {approx} v/c, where v is the local Keplerian speed.

  1. Dynamics of the Most Distant Kuiper Belt Objects

    NASA Astrophysics Data System (ADS)

    Volk, Kathryn; Malhotra, Renu; Wang, Xianyu

    2016-05-01

    We investigate the evolution of the most distant known Kuiper belt objects (KBOs) under the secular and resonant effects of the known planets in the Solar System as well as under the influence of a massive, unseen distant planet. The orbits of these distant KBOs evolve on a wide range of timescales (from millions to billions of years); most important are the changes in the objects’ perihelion distances which can dramatically change the relative domination of secular or resonant effects on their orbital evolution. Motivated by the period ratios of the distant KBOs, which are near simple integer ratios, we examine the properties of mean motion resonances with a hypothetical, unseen planet; we discuss how the uncertainties in the observed objects’ orbits compare to the widths of these hypothesized resonances. We also examine the timescales for secular orbital evolution and the timescales for scattering through close encounters in the models with and without the hypothetical planet to assess the case for such a planet.

  2. The formation of Kuiper-belt binaries through exchange reactions.

    PubMed

    Funato, Yoko; Makino, Junichiro; Hut, Piet; Kokubo, Eiichiro; Kinoshita, Daisuke

    2004-02-01

    Recent observations have revealed that an unexpectedly high fraction--a few per cent--of the trans-Neptunian objects (TNOs) that inhabit the Kuiper belt are binaries. The components have roughly equal masses, with very eccentric orbits that are wider than a hundred times the radius of the primary. Standard theories of binary asteroid formation tend to produce close binaries with circular orbits, so two models have been proposed to explain the unique characteristics of the TNOs. Both models, however, require extreme assumptions regarding the size distribution of the TNOs. Here we report a mechanism that is capable of producing binary TNOs with the observed properties during the early stages of their formation and growth. The only required assumption is that the TNOs were initially formed through gravitational instabilities in the protoplanetary dust disk. The basis of the mechanism is an exchange reaction in which a binary whose primary component is much more massive than the secondary interacts with a third body, whose mass is comparable to that of the primary. The low-mass secondary component is ejected and replaced by the third body in a wide but eccentric orbit. PMID:14765188

  3. Dynamical and collisional evolution of Kuiper belt binaries

    NASA Astrophysics Data System (ADS)

    Brunini, Adrián; Zanardi, Macarena

    2016-02-01

    We present numerical simulations of the evolution of synthetic transneptunian binaries (TNBs) under the influence of the solar perturbation, tidal friction, and collisions with the population of classical Kuiper belt objects (KBOs). We show that these effects, acting together, have strongly sculpted the primordial population of TNBs. If the population of classical KBOs have a power-law size distribution as the ones that are inferred from recent observational surveys, the fraction of surviving binaries at present would be ˜70 per cent of the primordial population. The orbits of the surviving synthetic systems match reasonably well the observed sample. The collisional process excites the mutual orbital eccentricity of the binaries, acting against the effect of tides. Therefore only ˜10 per cent of the objects reach total orbital circularization (e ≤ 10-4). In addition, our results predict that the population of contact binaries in the transneptunian region should be small. Ultrawide binaries are naturally obtained by the combined action of Kozai cycles and tidal friction and collisional evolution, being the number and orbital distribution of them very similar to the ones of the observed population.

  4. 1999 KUIPER PRIZE LECTURE. Cometary Origin of the Biosphere

    NASA Astrophysics Data System (ADS)

    Delsemme, Armand H.

    2000-08-01

    Most of the biosphere was brought on the primitive Earth by an intense bombardment of comets. This included the atmosphere, the seawater and those volatile carbon compounds needed for the emergence of life. Comets were thrown into the inner Solar System by the strong perturbation induced by the growth of the giant planets' cores. The bulk of the Earth's bombardment came from those comets that accreted in Jupiter's zone, where the original deuterium enrichment had been diminished by steam coming from the hot, inner parts of the Solar System. This steam had condensed into icy chunks before their accretion into larger cometary nuclei. In contrast, comets that accreted in the zones of the outer giant planets kept their interstellar isotopic enrichments. Those comets contributed to the Earth's bombardment for a small amount only; they were mostly ejected into the Oort cloud and are the major source of the long-period comets observed today. The short-period comets, which come from the Kuiper Belt, should also have the same interstellar enrichment. The deuterium enrichment of seawater, accurately predicted by the previous scenario, has become one of the best telltales for the cometary origin of our biosphere. This cometary origin may have far-reaching cosmological consequences, in particular for the origin of life in other planetary systems.

  5. THE SURFACE COMPOSITION OF LARGE KUIPER BELT OBJECT 2007 OR10

    SciTech Connect

    Brown, M. E.; Fraser, W. C.; Burgasser, A. J.

    2011-09-10

    We present photometry and spectra of the large Kuiper belt object 2007 OR10. The data show significant near-infrared absorption features due to water ice. While most objects in the Kuiper belt with water ice absorption this prominent have the optically neutral colors of water ice, 2007 OR10 is among the reddest Kuiper belt objects known. One other large Kuiper belt object-Quaoar-has similar red coloring and water ice absorption, and it is hypothesized that the red coloration of this object is due to irradiation of the small amounts of methane able to be retained on Quaoar. 2007 OR10, though warmer than Quaoar, is in a similar volatile retention regime because it is sufficiently larger that its stronger gravity can still retain methane. We propose, therefore, that the red coloration on 2007 OR10 is also caused by the retention of small amounts of methane. Positive detection of methane on 2007 OR10 will require spectra with higher signal to noise. Models for volatile retention on Kuiper belt objects appear to continue to do an excellent job reproducing all of the available observations.

  6. A single sub-kilometre Kuiper belt object from a stellar occultation in archival data.

    PubMed

    Schlichting, H E; Ofek, E O; Wenz, M; Sari, R; Gal-Yam, A; Livio, M; Nelan, E; Zucker, S

    2009-12-17

    The Kuiper belt is a remnant of the primordial Solar System. Measurements of its size distribution constrain its accretion and collisional history, and the importance of material strength of Kuiper belt objects. Small, sub-kilometre-sized, Kuiper belt objects elude direct detection, but the signature of their occultations of background stars should be detectable. Observations at both optical and X-ray wavelengths claim to have detected such occultations, but their implied abundances are inconsistent with each other and far exceed theoretical expectations. Here we report an analysis of archival data that reveals an occultation by a body with an approximately 500-metre radius at a distance of 45 astronomical units. The probability of this event arising from random statistical fluctuations within our data set is about two per cent. Our survey yields a surface density of Kuiper belt objects with radii exceeding 250 metres of 2.1(-1.7)(+4.8) x 10(7) deg(-2), ruling out inferred surface densities from previous claimed detections by more than 5sigma. The detection of only one event reveals a deficit of sub-kilometre-sized Kuiper belt objects compared to a population extrapolated from objects with radii exceeding 50 kilometres. This implies that sub-kilometre-sized objects are undergoing collisional erosion, just like debris disks observed around other stars. PMID:20016596

  7. On the Plutinos and Twotinos of the Kuiper Belt

    NASA Astrophysics Data System (ADS)

    Chiang, E. I.; Jordan, A. B.

    2002-12-01

    We illuminate dynamical properties of Kuiper belt objects (KBOs) in the 3:2 (Plutino) and 2:1 (``Twotino'') Neptunian resonances within the model of resonant capture and migration. We analyze a series of numerical integrations, each involving the four migratory giant planets and 400 test particles distributed throughout trans-Neptunian space, to measure the efficiencies of capture into the 3:2 and 2:1 resonances, the efficiencies of capture into Kozai-type secular resonances, and the libration centers and amplitudes of resonant particles, all as functions of the migration speed. We synthesize instantaneous snapshots of the spatial distribution of ~104 resonant KBOs, from which we derive the longitudinal variation of the sky density of each resonant family. Twotinos cluster +/-75° away from Neptune's longitude, while Plutinos cluster +/-90° away. Such longitudinal clustering persists even for surveys that are not volume limited in their ability to detect resonant KBOs. Remarkably, between -90° and -60° of Neptune's longitude we find the ratio of sky densities of Twotinos to Plutinos to be nearly unity, despite the greater average distance of Twotinos, assuming the two resonant populations are equal in number and share the same size, albedo, and inclination distributions. We couple our findings to observations to crudely estimate that the intrinsic Twotino population is within a factor of ~3 of the Plutino population. Most strikingly, the migration model predicts a possible asymmetry in the spatial distribution of Twotinos: more Twotinos may lie at longitudes behind that of Neptune than ahead of it. The magnitude of the asymmetry amplifies dramatically with faster rates of migration and can be as large as ~300%. A differential measurement of the sky density of 2:1 resonant objects behind and in front of Neptune's longitude would powerfully constrain the migration history of that planet.

  8. Interpreting the densities of the Kuiper belt's dwarf planets

    NASA Astrophysics Data System (ADS)

    Barr, Amy C.; Schwamb, Megan E.

    2016-08-01

    Kuiper belt objects (KBOs) with absolute magnitude less than 3 (radius ≳500 km), the dwarf planets, have a range of different ice/rock ratios, and are more rock-rich than their smaller counterparts. Many of these objects have moons, which suggests that collisions may have played a role in modifying their compositions. We show that the dwarf planets fall into two categories when analysed by their mean densities and satellite-to-primary size ratio. Systems with large moons, such as Pluto/Charon and Orcus/Vanth, can form in low-velocity grazing collisions in which both bodies retain their compositions. We propose that these systems retain a primordial composition, with a density of about 1.8 g cm-3. Triton, thought to be a captured KBO, could have lost enough ice during its early orbital evolution to explain its rock-enrichment relative to the primordial material. Systems with small moons, Eris, Haumea, and Quaoar, formed from a different type of collision in which icy material, perhaps a few tens of percent of the total colliding mass, is lost. The fragments would not remain in physical or dynamical proximity to the parent body. The ice loss process has not yet been demonstrated numerically, which could be due to the paucity of KBO origin simulations, or missing physical processes in the impact models. If our hypothesis is correct, we predict that large KBOs with small moons should be denser than the primordial material, and that the mean density of Orcus should be close to the primordial value.

  9. Interpreting the Densities of the Kuiper Belt's Dwarf Planets

    NASA Astrophysics Data System (ADS)

    Barr, Amy C.; Schwamb, Megan E.

    2016-05-01

    Kuiper Belt objects with absolute magnitude less than 3 (radius ≳500 km), the dwarf planets, have a range of different ice/rock ratios, and are more rock-rich than their smaller counterparts. Many of these objects have moons, which suggests that collisions may have played a role in modifying their compositions. We show that the dwarf planets fall into two categories when analysed by their mean densities and satellite-to-primary size ratio. Systems with large moons, such as Pluto/Charon and Orcus/Vanth, can form in low-velocity grazing collisions in which both bodies retain their compositions. We propose that these systems retain a primordial composition, with a density of about 1.8 g/cm3. Triton, thought to be a captured KBO, could have lost enough ice during its early orbital evolution to explain its rock-enrichment relative to the primordial material. Systems with small moons, Eris, Haumea, and Quaoar, formed from a different type of collision in which icy material, perhaps a few tens of percent of the total colliding mass, is lost. The fragments would not remain in physical or dynamical proximity to the parent body. The ice loss process has not yet been demonstrated numerically, which could be due to the paucity of KBO origin simulations, or missing physical processes in the impact models. If our hypothesis is correct, we predict that large KBOs with small moons should be denser than the primordial material, and that the mean density of Orcus should be close to the primordial value.

  10. Comparative Indicators of Education in the United States and Other G-20 Countries: 2015. NCES 2016-100

    ERIC Educational Resources Information Center

    Stephens, Maria; Warren, Laura K.; Harner, Ariana L.

    2015-01-01

    The "Comparative Indicators of Education" report series has been published on a biennial basis since it began in 2002, although this year's is the first to expand its focus to the G-20 countries, having previously been focused on the G-8 countries. "Comparative Indicators of Education in the United States and Other G-20 Countries:…

  11. Translating aboveground cosmic-ray neutron intensity to high-frequency soil moisture profiles at sub-kilometer scale

    NASA Astrophysics Data System (ADS)

    Rosolem, R.; Hoar, T.; Arellano, A.; Anderson, J. L.; Shuttleworth, W. J.; Zeng, X.; Franz, T. E.

    2014-11-01

    Above-ground cosmic-ray neutron measurements provide an opportunity to infer soil moisture at the sub-kilometer scale. Initial efforts to assimilate those measurements have shown promise. This study expands such analysis by investigating (1) how the information from aboveground cosmic-ray neutrons can constrain the soil moisture at distinct depths simulated by a land surface model, and (2) how changes in data availability (in terms of retrieval frequency) impact the dynamics of simulated soil moisture profiles. We employ ensemble data assimilation techniques in a "nearly-identical twin" experiment applied at semi-arid shrubland, rainfed agricultural field, and mixed forest biomes in the USA. The performance of the Noah land surface model is compared with and without assimilation of observations at hourly intervals, as well as every 2 days. Synthetic observations of aboveground cosmic-ray neutrons better constrain the soil moisture simulated by Noah in root-zone soil layers (0-100cm), despite the limited measurement depth of the sensor (estimated to be 12-20cm). The ability of Noah to reproduce a "true" soil moisture profile is remarkably good, regardless of the frequency of observations at the semi-arid site. However, soil moisture profiles are better constrained when assimilating synthetic cosmic-ray neutron observations hourly rather than every 2 days at the cropland and mixed forest sites. This indicates potential benefits for hydrometeorological modeling when soil moisture measurements are available at a relatively high frequency. Moreover, differences in summertime meteorological forcing between the semi-arid site and the other two sites may indicate a possible controlling factor to soil moisture dynamics in addition to differences in soil and vegetation properties.

  12. IceCube: A Cubic Kilometer Radiation Detector

    SciTech Connect

    IceCube Collaboration; Klein, Spencer R; Klein, S.R.

    2008-06-01

    IceCube is a 1 km{sup 3} neutrino detector now being built at the Amudsen-Scott South Pole Station. It consists of 4800 Digital Optical Modules (DOMs) which detect Cherenkov radiation from the charged particles produced in neutrino interactions. IceCube will observe astrophysical neutrinos with energies above about 100 GeV. IceCube will be able to separate {nu}{sub {mu}}, {nu}{sub t}, and {nu}{sub {tau}} interactions because of their different topologies. IceCube construction is currently 50% complete.

  13. 20 CFR 668.100 - What is the purpose of the programs established to serve Native American peoples (INA programs...

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... established to serve Native American peoples (INA programs) under section 166 of the Workforce Investment Act... LABOR INDIAN AND NATIVE AMERICAN PROGRAMS UNDER TITLE I OF THE WORKFORCE INVESTMENT ACT Purposes and Policies § 668.100 What is the purpose of the programs established to serve Native American peoples...

  14. 20 CFR 668.100 - What is the purpose of the programs established to serve Native American peoples (INA programs...

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... established to serve Native American peoples (INA programs) under section 166 of the Workforce Investment Act... Policies § 668.100 What is the purpose of the programs established to serve Native American peoples (INA... training services to Native American peoples and their communities. Services should be provided in...

  15. Remaining Sites Verification Package for the 100-B-20, 1716-B Maintenance Garage Underground Tank, Waste Site Reclassification Form 2006-019

    SciTech Connect

    L. M. Dittmer

    2006-09-27

    The 100-B-20 waste site, located in the 100-BC-1 Operable Unit of the Hanford Site, consisted of an underground oil tank that once serviced the 1716-B Maintenance Garage. The selected action for the 100-B-20 waste site involved removal of the oil tanks and their contents and demonstrating through confirmatory sampling that all cleanup goals have been met. In accordance with this evaluation, a reclassification status of interim closed out has been determined. The results demonstrate that the site will support future unrestricted land uses that can be represented by a rural-residential scenario. These results also show that residual concentrations support unrestricted future use of shallow zone soil and that contaminant levels remaining in the soil are protective of groundwater and the Columbia River.

  16. Volatile Loss and Classification of Kuiper Belt Objects

    NASA Astrophysics Data System (ADS)

    Johnson, Robert E.; Oza, Apurva; Young, Leslie A.; Volkov, Alexey N.; Schmidt, Carl A.

    2014-11-01

    Some of the largest Kuiper Belt Objects (KBOs) appear to have retained volatiles which affect their spectra, thermal energy balance, and atmospheres. Schaller & Brown (2007) (SB) estimated atmospheric escape rates from KBOs using Jeans escape from the surface, which they suggested gives a lower limit to the net atmospheric loss, and Levi & Podolak (2009) (LP) used a hydrodynamic model driven by the surface temperature. Based on recent molecular kinetic simulations, the SB escape rates are not necessarily lower limits and can be hugely in error, while the LP rates are valid only for KBOs with very small Jeans parameters (Volkov et al., 2011a,b). In addition, unless the atmosphere is thin or the body very small, escape can be driven primarily by the UV/EUV radiation absorbed in the upper atmosphere. Here we estimate the N2 loss from several KBOs, guided by recent molecular kinetic simulations that include thermal energy balance at the surface and heating of the upper atmosphere by UV/EUV irradiance. For the latter effect, we extrapolate simulations of escape from Pluto (Erwin et al., 2013; Zhu et al. 2014) using an energy limited escape model, which we have recently validated via molecular kinetic simulations (Johnson et al., 2013). In this way, we improve on current estimates of atmospheric retention and use the results to interpret the spectral differences observed. The longer-term goal is to connect detailed atmospheric loss mechanisms with a model for volatile transport (e.g., Young, 2014) in order to better describe recent KBO observations.ReferencesJohnson, R.E., A.N. Volkov and J.T. Erwin, Astrophys J. Lett. 768:L4, 2013.Levi, A. and M. Podolak, Icarus 202,681-693, 2009.Schaller, E.L. and M. E. Brown Astrophys. J., 659: L61-L64, 2007Volkov, A.N., R.E. Johnson, O.J. Tucker, J.T. Erwin, Astrophys. J. Lett. 729: L24, 2011a.Volkov, A.N, O.J. Tucker, J.T. Erwin, R.E. Johnson, Phys. of Fluids 23, 066601, 2011b.Young, L.A. , Icarus 221, 80-88, 2014Zhu, X., Strobel, D

  17. The absolute magnitude distribution of Kuiper Belt objects

    SciTech Connect

    Fraser, Wesley C.; Brown, Michael E.; Morbidelli, Alessandro; Parker, Alex; Batygin, Konstantin

    2014-02-20

    Here we measure the absolute magnitude distributions (H-distribution) of the dynamically excited and quiescent (hot and cold) Kuiper Belt objects (KBOs), and test if they share the same H-distribution as the Jupiter Trojans. From a compilation of all useable ecliptic surveys, we find that the KBO H-distributions are well described by broken power laws. The cold population has a bright-end slope, α{sub 1}=1.5{sub −0.2}{sup +0.4}, and break magnitude, H{sub B}=6.9{sub −0.2}{sup +0.1} (r'-band). The hot population has a shallower bright-end slope of, α{sub 1}=0.87{sub −0.2}{sup +0.07}, and break magnitude H{sub B}=7.7{sub −0.5}{sup +1.0}. Both populations share similar faint-end slopes of α{sub 2} ∼ 0.2. We estimate the masses of the hot and cold populations are ∼0.01 and ∼3 × 10{sup –4} M {sub ⊕}. The broken power-law fit to the Trojan H-distribution has α{sub 1} = 1.0 ± 0.2, α{sub 2} = 0.36 ± 0.01, and H {sub B} = 8.3. The Kolmogorov-Smirnov test reveals that the probability that the Trojans and cold KBOs share the same parent H-distribution is less than 1 in 1000. When the bimodal albedo distribution of the hot objects is accounted for, there is no evidence that the H-distributions of the Trojans and hot KBOs differ. Our findings are in agreement with the predictions of the Nice model in terms of both mass and H-distribution of the hot and Trojan populations. Wide-field survey data suggest that the brightest few hot objects, with H{sub r{sup ′}}≲3, do not fall on the steep power-law slope of fainter hot objects. Under the standard hierarchical model of planetesimal formation, it is difficult to account for the similar break diameters of the hot and cold populations given the low mass of the cold belt.

  18. Dynamic Tensile Strength of Low Temperature Ice and Kuiper Belt Size Distributions

    NASA Astrophysics Data System (ADS)

    Ahrens, Thomas J.; Fat'yanov, O. V.; Engelhardt, H.; Fraser, W. C.

    2009-09-01

    We model mutual gravitationally driven impact interactions in a nearly gas-free environment of the Kuiper belt (KB) and use low-temperature (< 100 K) ice dynamic strength dependent collisional out-come (accretion vs. erosion and fragmentation) models. These lead to theoretically predictable distributions of object number density, vs. mass distributions. These derived mass distributions are comparable to the now rapidly growing KB survey data. Tensional failure of single and polycrystalline ice in the temperature range from 263 to 128 K was measured for high strain rate, c.a. 104 s-1, dynamic loading conditions. Experiments, similar to Lange and Ahrens(1991)(LA), were conducted using a gas gun launched Lexan projectile. The liquid nitrogen cooled ice target approaching KB-like temperatures was partially confined, rather than using the LA confined geometry. Another set of experiments used a drop tube projectile launcher within the 263 K Caltech Ice Laboratory and at 163 K in a liquid nitrogen cooled chamber. New experiments give tensile strengths of 7.6±1.5 MPa at 263 K and 9.1±1.5 MPa at 163 K for unconfined, free of visual initial defects and measurable imperfections ice samples. The new strengths are lower than the earlier LA data ( 17 MPa). The major differences arise from ice target assembly. LA used polycrystalline ice samples confined in annular stainless steel target rings. New measurements were partially confined, in not initially contacting concentric target rings. Later shots used unconfined configurations with ice pellets affixed to aluminum foil. Circumferential confinement is known to increase the material damage threshold upon both compression and tensile loading. Previous confinement in LA is the main cause of the above discrepancy. Present tensile strengths are only a few times higher than 0.7 - 3.0 MPa summarized in Petrovic (2003) for quasistatic tension at 10-7 to 10-3 s-1 strain rate.

  19. EQUILIBRIUM CONFIGURATIONS OF SYNCHRONOUS BINARIES: NUMERICAL SOLUTIONS AND APPLICATION TO KUIPER BELT BINARY 2001 QG{sub 298}

    SciTech Connect

    Gnat, Orly; Sari, Re'em

    2010-08-20

    We present numerical computations of the equilibrium configurations of tidally locked homogeneous binaries rotating in circular orbits. Unlike the classical Roche approximations, we self-consistently account for the tidal and rotational deformations of both components, and relax the assumptions of ellipsoidal configurations and Keplerian rotation. We find numerical solutions for mass ratios q between 10{sup -3} and 1, starting at a small angular velocity for which tidal and rotational deformations are small, and following a sequence of increasing angular velocities. Each series terminates at an appropriate 'Roche limit', above which no equilibrium solution can be found. Even though the Roche limit is crossed before the 'Roche lobe' is filled, any further increase in the angular velocity will result in mass-loss. For close, comparable-mass binaries, we find that local deviations from ellipsoidal forms may be as large as 10%-20%, and departures from Keplerian rotation are significant. We compute the light curves that arise from our equilibrium configurations, assuming their distance is >>1 AU (e.g., in the Kuiper Belt). We consider both backscatter (proportional to the projected area) and diffuse (Lambert) reflections. Backscatter reflection always yields two minima of equal depths. Diffuse reflection, which is sensitive to the surface curvature, generally gives rise to unequal minima. We find detectable intensity differences of up to 10% between our light curves and those arising from the Roche approximations. Finally, we apply our models to Kuiper Belt binary 2001 QG{sub 298}, and find a nearly edge-on binary with a mass ratio q = 0.93{sup +0.07}{sub -0.03}, angular velocity {omega}{sup 2}/G{rho} = 0.333 {+-} 0.001 (statistical errors only), and pure diffuse reflection. For the observed period of 2001 QG{sub 298}, these parameters imply a bulk density {rho} = 0.72 {+-} 0.04 g cm{sup -3}.

  20. 77 FR 76959 - Energy Conservation Program: Request for Exclusion of 100 Watt R20 Short Incandescent Reflector...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-31

    ...) lamp that falls within the voltage range of covered IRLs (hereafter ``R20 short lamp''). 75 FR 80731... in July 2009 (hereafter ``2009 Lamps Rule''). 74 FR 34080 (July 14, 2009).\\3\\ \\3\\ Information... allow pools and spas to be supplied with 120V electricity. 75 FR 80731 (Dec. 23, 2010) As stated in...

  1. 75 FR 80731 - Request for Exclusion of 120 Volt, 100 Watt R20 Short Incandescent Reflector Lamps

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-23

    ..., which is marketed for use in hot tub spas. Public comment is requested on whether DOE should grant the... watt R20 short, which is marketed exclusively for use in hot tub spas sold into specific jurisdictions... capacity for use in certain types of hot tub spas that require smaller dimensions--would lead to...

  2. Radioactive plume from the Three Mile Island accident: xenon-133 in air at a distance of 375 kilometers.

    PubMed

    Wahlen, M; Kunz, C O; Matuszek, J M; Mahoney, W E; Thompson, R C

    1980-02-01

    The transit of an air mass containing radioactive gas released from the Three Mile Island reactor was recorded in Albany, New York, by measuring xenon-133. These measurements provide an evaluation of Three Mile Island effluents to distances greater than 100 kilometers. Two independent techniques identified xenon-133 in ambient air at concentrations as high as 3900 picocuries per cubic meter. The local gamma-ray whole-body dose from the passing radioactivity amounted to 0.004 millirem, or 0.004 percent of the annual dose from natural sources. PMID:7352276

  3. Suppression of repetitive surface exfoliation of Inconel 625 implanted sequentially with helium ions of different energies (20 100 keV)

    NASA Astrophysics Data System (ADS)

    Rao, A. S.; Whitton, J. L.; Kaminsky, M.

    Studies were conducted to explore if the surface exfoliation of Inconel 625, typical for 100 keV 4He + irradiations can be reduced by pre-irradiating the surfaces with helium ions sequentially over the energy range 20 to 50 keV. Polished, polycrystalline Inconel 625 samples were irradiated at 298K and 573K with 4He + at six different energies in the range from 20 to 50 keV in an order of decreasing energies. For each energy the dose was 0.13 C/cm 2, resulting in a total dose of 0.89 C/cm 2. Subsequently, these samples were implanted with 100 keV 4He + to a dose of 1.0 C/cm 2 or 2.0 C/cm 2. The results reveal that the low energy 4He + implants prior to the 100 keV 4He + implant reduce significantly the erosion yield typical for 100-keV 4He + irradiations alone. For 573K these reduced yields are still about one order of magnitude greater than physical sputtering yields.

  4. Cold DUst around NEarby Stars (DUNES). First results. A resolved exo-Kuiper belt around the solar-like star ζ2 Ret

    NASA Astrophysics Data System (ADS)

    Eiroa, C.; Fedele, D.; Maldonado, J.; González-García, B. M.; Rodmann, J.; Heras, A. M.; Pilbratt, G. L.; Augereau, J.-Ch.; Mora, A.; Montesinos, B.; Ardila, D.; Bryden, G.; Liseau, R.; Stapelfeldt, K.; Launhardt, R.; Solano, E.; Bayo, A.; Absil, O.; Arévalo, M.; Barrado, D.; Beichmann, C.; Danchi, W.; Del Burgo, C.; Ertel, S.; Fridlund, M.; Fukagawa, M.; Gutiérrez, R.; Grün, E.; Kamp, I.; Krivov, A.; Lebreton, J.; Löhne, T.; Lorente, R.; Marshall, J.; Martínez-Arnáiz, R.; Meeus, G.; Montes, D.; Morbidelli, A.; Müller, S.; Mutschke, H.; Nakagawa, T.; Olofsson, G.; Ribas, I.; Roberge, A.; Sanz-Forcada, J.; Thébault, P.; Walker, H.; White, G. J.; Wolf, S.

    2010-07-01

    We present the first far-IR observations of the solar-type stars δ Pav, HR 8501, 51 Peg and ζ2 Ret, taken within the context of the DUNES Herschel open time key programme (OTKP). This project uses the PACS and SPIRE instruments with the objective of studying infrared excesses due to exo-Kuiper belts around nearby solar-type stars. The observed 100 μm fluxes from δ Pav, HR 8501, and 51 Peg agree with the predicted photospheric fluxes, excluding debris disks brighter than Ldust/Lstar 5 × 10-7 (1σ level) around those stars. A flattened, disk-like structure with a semi-major axis of 100 AU in size is detected around ζ2 Ret. The resolved structure suggests the presence of an eccentric dust ring, which we interpret as an exo-Kuiper belt with Ldust/Lstar ≈ 10-5. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.

  5. Kenneth Essex Edgeworth—Victorian polymath and founder of the Kuiper belt?

    NASA Astrophysics Data System (ADS)

    McFarland, John

    This article is a biographical note on Kenneth Essex Edgeworth (1880-1972), Army officer, engineer, economist and independent theoretical astronomer. Abibliography of Edgeworth's known papers is incorporated, and his interesting cosmogonic theories are highlighted, in particular his postulation in 1943 of a source of potential comets occupying the region of the solar system beyond Neptune, recently termed the Kuiper belt.

  6. A Single Institution's First 100 Patients Undergoing Laparoscopic Anti-Reflux Fundoplications: Where Are They 20 Years Later?

    PubMed

    Sadowitz, Benjamin D; Luberice, Kenneth; Bowman, Ty A; Viso, Alexandra M; Ayala, Daniel E; Ross, Sharona B; Rosemurgy, Alexander S

    2015-08-01

    Although anti-reflux surgery has been used liberally over the past decades for the treatment of gastroesophageal reflux disease (GERD), few studies report follow-up after 10 years. This study was undertaken to report follow-up on 100 consecutive GERD patients up to 22 years after utilizing a laparoscopic fundoplication. Hundred consecutive patients undergoing laparoscopic fundoplication for GERD were prospectively followed beginning in 1992. The frequency and severity of symptoms before and after laparoscopic fundoplication were scored on a Likert scale (1 = never/none to 10 = always/very bothersome). Median data are reported. Of the 100 patients who underwent laparoscopic fundoplication for their GERD, nine were reoperations. Twenty-six patients are deceased on average 11 years after their fundoplications. Seventy-four patients are alive, with 27 patients, actively followed for 19 years after their fundoplications. At most recent follow-up, patients experienced long-term amelioration of symptom frequency and severity after fundoplication (e.g., heartburn frequency = 8-2, severity = 8-1; P < 0.01 for each). Eighty-four per cent of patients rated their symptom frequency as less than once per month. Eighty-eight per cent of patients were satisfied with their postoperative results, and 95 per cent of patients confirmed they would have the operation again knowing what they know now. Long-term follow-up documents high patient satisfaction and durable symptomatic relief up to two decades after laparoscopic fundoplication for GERD. Patients should seek this operation not only for symptomatic relief, but to mitigate the deleterious effects of long-term acid exposure and anti-acid therapy. PMID:26215241

  7. Warm exo-Zodi from cool exo-Kuiper belts: the significance of P-R drag and the inference of intervening planets

    NASA Astrophysics Data System (ADS)

    Kennedy, Grant M.; Piette, Anjali

    2015-05-01

    Poynting-Robertson (P-R) drag has been considered an ineffective mechanism for delivering dust to regions interior to the cool Kuiper belt analogues seen around other Sun-like stars. This conclusion is however based on the very large contrast in dust optical depth between the parent belt and the interior regions that results from the dominance of collisions over drag in systems with detectable cool belts. Here, we show that the levels of habitable zone dust arising from detectable Kuiper belt analogues can be tens to a few hundreds of times greater than the optical depth in the Solar Zodiacal cloud. Dust enhancements of more than a few tens of `zodi' are expected to hinder future Earth-imaging missions, but relatively few undetectable Kuiper belts result in such levels, particularly around stars older than a few Gyr. Thus, current mid- to far-IR photometric surveys have already identified most of the 20-25 per cent of nearby stars where P-R drag from outer belts could seriously impact Earth-imaging. The Large Binocular Telescope Interferometer should easily detect such warm dust around many nearby stars with outer belts, and will provide insight into currently unclear details of the competition between P-R drag and collisions. Given sufficient confidence in future models, the inevitability of P-R drag means that the non-detection of warm dust where detectable levels were expected could be used to infer additional dust removal process, the most likely being the presence of intervening planets.

  8. Green's function approximation from cross-correlations of 20-100 Hz noise during a tropical storm.

    PubMed

    Brooks, Laura A; Gerstoft, Peter

    2009-02-01

    Approximation of Green's functions through cross-correlation of acoustic signals in the ocean, a method referred to as ocean acoustic interferometry, is potentially useful for estimating parameters in the ocean environment. Travel times of the main propagation paths between hydrophone pairs were estimated from interferometry of ocean noise data that were collected on three L-shaped arrays off the New Jersey coast while Tropical Storm Ernesto passed nearby. Examination of the individual noise spectra and their mutual coherence reveals that the coherently propagating noise is dominated by signals of less than 100 Hz. Several time and frequency noise normalization techniques were applied to the low frequency data in order to determine the effectiveness of each technique for ocean acoustic applications. Travel times corresponding to the envelope peaks of the noise cross-correlation time derivatives of data were extracted from all three arrays, and are shown to be in agreement with the expected direct, surface-reflected, and surface-bottom-reflected interarray hydrophone travel times. The extracted Green's function depends on the propagating noise. The Green's function paths that propagate horizontally are extracted from long distance shipping noise, and during the storm the more vertical paths are extracted from breaking waves. PMID:19206850

  9. Generation of sub-20 fs Tunable Visible Pulses from a 100 kHz NOPA For Measuring Ultrafast Heterogeneous Electron Transfer

    NASA Astrophysics Data System (ADS)

    Ernstorfer, R.; Gundlach, L.; Zimmermann, C.; Willig, F.; Eichberger, R.; Riedle, E.

    We describe the design and performance of a noncollinear optical parametric amplifier that can be pumped by the output of a commercial 100 kHz Ti:sapphire regenerative amplifier. The output of the NOPA is compressed to sub-20 fs length and tunable from 460 nm to beyond 1 pm. The maximum pulse energy is 750 nJ. The system is used to measure photoinduced electron transfer in a perylene/TiO2 system with unprecedented temporal resolution.

  10. Lunar textural analysis based on WAC-derived kilometer-scale roughness and entropy maps

    NASA Astrophysics Data System (ADS)

    Li, Bo; Wang, XueQiang; Zhang, Jiang; Chen, Jian; Ling, Zongcheng

    2016-06-01

    In general, textures are thought to be some complicated repeated patterns formed by elements, or primitives which are sorted in certain rules. Lunar surfaces record the interactions between its outside environment and itself, thus, based on high-resolution DEM model or image data, there are some topographic features which have different roughness and entropy values or signatures on lunar surfaces. Textures of lunar surfaces can help us to concentrate on typical topographic and photometric variations and reveal the relationships between obvious features (craters, impact basins, sinuous rilles (SRs) and ridges) with resurfacing processes on the Moon. In this paper, the term surface roughness is an expression of the variability of a topographic or photometric surface at kilometer scale, and the term entropy can characterize the variability inherent in a geological and topographic unit and evaluate the uncertainty of predictions made by a given geological process. We use the statistical moments of gray-level histograms in different-sized neighborhoods (e.g., 3, 5, 10, 20, 40 and 80 pixels) to compute the kilometer-scale roughness and entropy values, using the mosaic image from 70°N to 70°S obtained by Lunar Reconnaissance Orbiter (LRO) Wide Angle Camera (WAC). Large roughness and entropy signatures were only found in the larger scale maps, while the smallest 3-pixel scale map had more disorderly and unsystematic textures. According to the entropy values in 10-pixel scale entropy map, we made a frequency curve and categorized lunar surfaces into three types, shadow effects, maria and highlands. A 2D scatter plot of entropy versus roughness values was produced and we found that there were two point clusters corresponding to the highlands and maria, respectively. In the last, we compared the topographic and photometric signatures derived from Lunar Orbiter Laser Altimeter (LOLA) data and WAC mosaic image. On the lunar surfaces, the ridges have obvious multilevel

  11. BIPM/CIPM key comparison CCM.FF-K4.1.2011. Final report for volume of liquids at 20 L and 100 mL

    NASA Astrophysics Data System (ADS)

    Arias, R.; Maldonado, M.; Batista, E.; Jintao, W.; Malengo, A.; Malta, D.; Ondodro, D.; Penttinen, O.; Smits, E.; Wright, J.

    2015-01-01

    By agreement at the 10th WGFF meeting, the international comparison CCM.FF-K4.1.2011, for volume of liquids at 20 L and 100 mL, was performed during 2012-2014. Specially designed stainless steel pipettes were used as transfer standards for 20 L, whereas commercially available pycnometers were used for 100 mL. No discrepant measurements were distinguished on the 20 L artifacts. The largest difference between two NMIs was 0.0042 %, whereas the average degrees of equivalence for artifacts 710-04 and 710-05 resulted in 0.0001 % and 0.0005 %, respectively. Only one participant produced anomalous results for 100 mL measurements and results for artifacts 03.01.16 and 03.01.17 were all fully consistent with each other. The average degrees of equivalence for artifacts 03.01.16 and 03.01.17 were 0.00017 % and 0.0011 %, respectively. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by CCM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

  12. Kilometer-Scale Topographic Roughness of Mercury: Correlation with Geologic Features and Units

    NASA Technical Reports Server (NTRS)

    Kreslavsky, Mikhail A.; Head, James W.; Neumann, Gregory A.; Zuber, Maria T.; Smith, David E.

    2014-01-01

    We present maps of the topographic roughness of the northern circumpolar area of Mercury at kilometer scales. The maps are derived from range profiles obtained by the Mercury Laser Altimeter (MLA) instrument onboard the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) mission. As measures of roughness, we used the interquartile range of profile curvature at three baselines: 0.7 kilometers, 2.8 kilometers, and 11 kilometers. The maps provide a synoptic overview of variations of typical topographic textures. They show a dichotomy between the smooth northern plains and rougher, more heavily cratered terrains. Analysis of the scale dependence of roughness indicates that the regolith on Mercury is thicker than on the Moon by approximately a factor of three. Roughness contrasts within northern volcanic plains of Mercury indicate a younger unit inside Goethe basin and inside another unnamed stealth basin. These new data permit interplanetary comparisons of topographic roughness.

  13. Optimization of transistor design including large signal device/circuit interactions at extremely high frequencies (20-100+GHz)

    NASA Technical Reports Server (NTRS)

    Levy, Ralph; Grubin, H. L.

    1991-01-01

    Transistor design for extremely high frequency applications requires consideration of the interaction between the device and the circuit to which it is connected. Traditional analytical transistor models are to approximate at some of these frequencies and may not account for variations of dopants and semiconductor materials (especially some of the newer materials) within the device. Physically based models of device performance are required. These are based on coupled systems of partial differential equations and typically require 20 minutes of Cray computer time for a single AC operating point. A technique is presented to extract parameters from a few partial differential equation solutions for the device to create a nonlinear equivalent circuit model which runs in approximately 1 second of personal computer time. This nonlinear equivalent circuit model accurately replicates the contact current properties of the device as computed by the partial differential solver on which it is based. Using the nonlinear equivalent circuit model of the device, optimization of systems design can be performed based on device/circuit interactions.

  14. The Diameter of Pluto: A Re-Analysis of Kuiper's Disk Meter Measurements

    NASA Astrophysics Data System (ADS)

    Marcialis, R. L.; Merline, W. J.

    1998-09-01

    In 1948--1950, G.P. Kuiper (1950. PASP 62, 133--137) used a disk meter to ``measure'' the diameter of Pluto. This instrument (Camichel, 1944. Comptes Rendus 219, 21--22) is designed to produce an artificial luminous disk of controllable brightness, color, and diameter, allowing the user to estimate angular diameters. Kuiper's result, 0\\farcs 23 (0.46 d_⊕ or 5 870 km), stood as the definitive diameter determination for over a quarter century. We now know that at the time of the 1950 observation, Pluto's disk actually was 0.('') 0445, with 0.('') 0248 Charon offset by (rho , theta ) = (0.('') 6767, 46.(deg) 6). Most people have discounted the observation as faulty, in spite of the fact that Kuiper and Humason repeatedly measured 0.('') 23 for Pluto, and 0.('') 11 for a nearby mag 11 star. Can the result be reconciled with what they actually observed? Surprisingly, it can! We have run numerical simulations of the experiment. The ``realistic'' CCD model of Merline and Howell (1995. Exp. Astron. 6, 163--210) was modified to simulate the human eye. Synthetic images were generated for a wide variety of conditions (seeing, sky brightness, eye response, Pluto/Charon brightness ratio, etc.). A double-blind experiment was then performed. Under the assumption of a radially-symmetric point spread function (i.e., a single source), widths (FWHM) of these simulated images were extracted for both the Pluto--Charon blend and the nearby comparison star. We conclude that, although Charon was not resolved, it did indeed have an unanticipated, but understandable effect on Kuiper's measurement. The result of our modelling confirms that Kuiper should have seen approximately what was measured. It is not necessary to invoke changes in seeing between Pluto and star measurements. Kuiper's result is further consistent with a Pluto/Charon light ratio of ≈> 8.2:1. This compares favorably to the ratio required for no stellar occultation in 1965 (Halliday et al. 1966. PASP 78, 113

  15. Growth and evolution of small porous icy bodies with an adaptive-grid thermal evolution code. I. Application to Kuiper belt objects and Enceladus

    NASA Astrophysics Data System (ADS)

    Prialnik, Dina; Merk, Rainer

    2008-09-01

    We present a new 1-dimensional thermal evolution code suited for small icy bodies of the Solar System, based on modern adaptive grid numerical techniques, and suited for multiphase flow through a porous medium. The code is used for evolutionary calculations spanning 4.6×10 yr of a growing body made of ice and rock, starting with a 10 km radius seed and ending with an object 250 km in radius. Initial conditions are chosen to match two different classes of objects: a Kuiper belt object, and Saturn's moon Enceladus. Heating by the decay of 26Al, as well as long-lived radionuclides is taken into account. Several values of the thermal conductivity and accretion laws are tested. We find that in all cases the melting point of ice is reached in a central core. Evaporation and flow of water and vapor gradually remove the water from the core and the final (present) structure is differentiated, with a rocky, highly porous core of 80 km radius (and up to 160 km for very low conductivities). Outside the core, due to refreezing of water and vapor, a compact, ice-rich layer forms, a few tens of km thick (except in the case of very high conductivity). If the ice is initially amorphous, as expected in the Kuiper belt, the amorphous ice is preserved in an outer layer about 20 km thick. We conclude by suggesting various ways in which the code may be extended.

  16. Conceptual design of electrical balance of plant for advanced battery energy storage facility. Annual report, March 1979. [20-MW, 100 MWh

    SciTech Connect

    1980-01-01

    Large-scale efforts are in progress to develop advanced batteries for utility energy storage systems. Realization of the full benefits available from those systems requires development, not only of the batteries themselves, but also the ac/dc power converter, the bulk power interconnecting equipment, and the peripheral electric balance of plant equipment that integrate the battery/converter into a properly controlled and protected energy system. This study addresses these overall system aspects; although tailored to a 20-MW, 100-MWh lithium/sulfide battery system, the technology and concepts are applicable to any battery energy storage system. 42 figures, 14 tables. (RWR)

  17. Optical properties of (Se{sub 80}Te{sub 20}){sub 100−x}Ag{sub x} (0 ≤ x ≤ 4) thin films

    SciTech Connect

    Singh, D. Kumar, S. Sandhu, S. Thangaraj, R.

    2014-04-24

    Thin films of (Se{sub 80}Te{sub 20}){sub 100−x}Ag{sub x} (0 ≤ x ≤ 4) glasses were prepared by thermal evaporation of the bulk samples. The transmittance (T) and reflection (R) spectra of amorphous thin films were obtained in the spectral region in the range 400–2500 nm. The optical band gap (E{sub g}) has been determined by Tauc’s extrapolation method. The surface morphology has been determined by the Scanning Electron Microscopy (SEM)

  18. Using Intermediate-Luminosity Optical Transients (ILOTs) to reveal extended extra-solar Kuiper belt objects

    NASA Astrophysics Data System (ADS)

    Bear, Ealeal; Soker, Noam

    2016-07-01

    We suggest that in the rare case of an Intermediate-Luminosity Optical Transient (ILOT) event, evaporation of extra-solar Kuiper belt objects (ExtraKBOs) at distances of d ≈ 500 – 10 000 AU from the ILOT can be detected. If the ILOT lasts for 1 month to a few years, enough dust might be ejected from the ExtraKBOs for the infrared (IR) emission to be detected. Because of the large distance of the ExtraKBOs, tens of years will pass before the ILOT wind disperses the dust. We suggest that after an ILOT outburst, there is a period of months to several years during which IR excess emission might hint at the existence of a Kuiper belt analog (ExtraK-Belt).

  19. KUIPER BELT OBJECT OCCULTATIONS: EXPECTED RATES, FALSE POSITIVES, AND SURVEY DESIGN

    SciTech Connect

    Bickerton, S. J.; Welch, D. L.; Kavelaars, J. J. E-mail: welch@physics.mcmaster.ca

    2009-05-15

    A novel method of generating artificial scintillation noise is developed and used to evaluate occultation rates and false positive rates for surveys probing the Kuiper Belt with the method of serendipitous stellar occultations. A thorough examination of survey design shows that (1) diffraction-dominated occultations are critically (Nyquist) sampled at a rate of 2 Fsu{sup -1}, corresponding to 40 s{sup -1} for objects at 40 AU, (2) occultation detection rates are maximized when targets are observed at solar opposition, (3) Main Belt asteroids will produce occultations light curves identical to those of Kuiper Belt Objects (KBOs) if target stars are observed at solar elongations of: 116{sup 0} {approx}< {epsilon} {approx}< 125 deg., or 131 deg. {approx}< {epsilon} {approx}< 141 deg., and (4) genuine KBO occultations are likely to be so rare that a detection threshold of {approx}>7-8{sigma} should be adopted to ensure that viable candidate events can be disentangled from false positives.

  20. Studies of extra-solar Oort clouds and the Kuiper disk

    NASA Technical Reports Server (NTRS)

    Stern, S. Alan

    1996-01-01

    We are conducting research designed to enhance our understanding of the evolution and detectability of comet clouds and disks. According to 'standard' theory, both the Kuiper Belt and the Oort Cloud are (at least in part) natural products of the planetary accumulation stage of solar system formation. One expects such assemblages to be a common attribute of other solar systems. Therefore, searches for comet disks and clouds orbiting other stars offer a new method for inferring the presence of planetary systems. This project consists of two efforts: (1) observational work to predict and search for the signatures of Oort Clouds and comet disks around other stars; and (2) modelling studies of the formation and evolution of the Kuiper Belt (KB) and similar assemblages that may reside around other stars, including beta Pic.

  1. Kuiper Belt Object Orbiter Using Advanced Radioisotope Power Sources and Electric Propulsion

    NASA Technical Reports Server (NTRS)

    Oleson, Steven R.; McGuire, Melissa L.; Dankanich, John; Colozza, Anthony; Schmitz, Paul; Khan, Omair; Drexler, Jon; Fittje, James

    2011-01-01

    A joint NASA GRC/JPL design study was performed for the NASA Radioisotope Power Systems Office to explore the use of radioisotope electric propulsion for flagship class missions. The Kuiper Belt Object Orbiter is a flagship class mission concept projected for launch in the 2030 timeframe. Due to the large size of a flagship class science mission larger radioisotope power system building blocks were conceptualized to provide the roughly 4 kW of power needed by the NEXT ion propulsion system and the spacecraft. Using REP the spacecraft is able to rendezvous with and orbit a Kuiper Belt object in 16 years using either eleven (no spare) 420 W advanced RTGs or nine (with a spare) 550 W advanced Stirling Radioisotope systems. The design study evaluated integrating either system and estimated impacts on cost as well as required General Purpose Heat Source requirements.

  2. New Horizons Science Photos from NASA's Pluto-Kuiper Belt Mission

    DOE Data Explorer

    DOE provided the power supply for NASA's New Horizons Mission, a mission to the Pluto and Charon, a double-planet system, and the Kuiper Belt. There are science photos posted on the New Horizons website, along with mission photos, spacecraft images, launch photos, posters and renderings that are both scientific and artistic. The images can be searched by keywords, by date, or by subject topic. They can also be browsed as an entire list. Each image has a detailed description.

  3. A SOUTHERN SKY AND GALACTIC PLANE SURVEY FOR BRIGHT KUIPER BELT OBJECTS

    SciTech Connect

    Sheppard, Scott S.; Udalski, Andrzej; Kubiak, Marcin; Pietrzynski, Grzegorz; Poleski, Radoslaw; Soszynski, Igor; Szymanski, Michal K.; Ulaczyk, Krzysztof; Trujillo, Chadwick

    2011-10-15

    About 2500 deg{sup 2} of sky south of declination -25{sup 0} and/or near the Galactic Plane were surveyed for bright outer solar system objects. This survey is one of the first large-scale southern sky and Galactic Plane surveys to detect dwarf planets and other bright Kuiper Belt Objects in the trans-Neptunian region. The survey was able to obtain a limiting R-band magnitude of 21.6. In all, 18 outer solar system objects were detected, including Pluto which was detected near the Galactic center using optimal image subtraction techniques to remove the high stellar density background. Fourteen of the detections were previously unknown trans-Neptunian objects, demonstrating that the southern sky had not been well searched to date for bright outer solar system objects. Assuming moderate albedos, several of the new discoveries from this survey could be in hydrostatic equilibrium and thus could be considered dwarf planets. Combining this survey with previous surveys from the northern hemisphere suggests that the Kuiper Belt is nearly complete to around 21st magnitude in the R band. All the main dynamical classes in the Kuiper Belt are occupied by at least one dwarf-planet-sized object. The 3:2 Neptune resonance, which is the innermost well-populated Neptune resonance, has several large objects while the main outer Neptune resonances such as the 5:3, 7:4, 2:1, and 5:2 do not appear to have any large objects. This indicates that the outer resonances are either significantly depleted in objects relative to the 3:2 resonance or have a significantly different assortment of objects than the 3:2 resonance. For the largest objects (H < 4.5 mag), the scattered disk population appears to have a few times more objects than the main Kuiper Belt (MKB) population, while the Sedna population could be several times more than that of the MKB.

  4. Texture descriptions of lunar surface derived from LOLA data: Kilometer-scale roughness and entropy maps

    NASA Astrophysics Data System (ADS)

    Li, Bo; Ling, Zongcheng; Zhang, Jiang; Chen, Jian; Wu, Zhongchen; Ni, Yuheng; Zhao, Haowei

    2015-11-01

    The lunar global texture maps of roughness and entropy are derived at kilometer scales from Digital Elevation Models (DEMs) data obtained by Lunar Orbiter Laser Altimeter (LOLA) aboard on Lunar Reconnaissance Orbiter (LRO) spacecraft. We use statistical moments of a gray-level histogram of elevations in a neighborhood to compute the roughness and entropy value. Our texture descriptors measurements are shown in global maps at multi-sized square neighborhoods, whose length of side is 3, 5, 10, 20, 40 and 80 pixels, respectively. We found that large-scale topographical changes can only be displayed in maps with longer side of neighborhood, but the small scale global texture maps are more disorderly and unsystematic because of more complicated textures' details. Then, the frequency curves of texture maps are made out, whose shapes and distributions are changing as the spatial scales increases. Entropy frequency curve with minimum 3-pixel scale has large fluctuations and six peaks. According to this entropy curve we can classify lunar surface into maria, highlands, different parts of craters preliminarily. The most obvious textures in the middle-scale roughness and entropy maps are the two typical morphological units, smooth maria and rough highlands. For the impact crater, its roughness and entropy value are characterized by a multiple-ring structure obviously, and its different parts have different texture results. In the last, we made a 2D scatter plot between the two texture results of typical lunar maria and highlands. There are two clusters with largest dot density which are corresponded to the lunar highlands and maria separately. In the lunar mare regions (cluster A), there is a high correlation between roughness and entropy, but in the highlands (Cluster B), the entropy shows little change. This could be subjected to different geological processes of maria and highlands forming different landforms.

  5. Five-Kilometers Time Trial: Preliminary Validation of a Short Test for Cycling Performance Evaluation

    PubMed Central

    Dantas, Jose Luiz; Pereira, Gleber; Nakamura, Fabio Yuzo

    2015-01-01

    Background: The five-kilometer time trial (TT5km) has been used to assess aerobic endurance performance without further investigation of its validity. Objectives: This study aimed to perform a preliminary validation of the TT5km to rank well-trained cyclists based on aerobic endurance fitness and assess changes of the aerobic endurance performance. Materials and Methods: After the incremental test, 20 cyclists (age = 31.3 ± 7.9 years; body mass index = 22.7 ± 1.5 kg/m2; maximal aerobic power = 360.5 ± 49.5 W) performed the TT5km twice, collecting performance (time to complete, absolute and relative power output, average speed) and physiological responses (heart rate and electromyography activity). The validation criteria were pacing strategy, absolute and relative reliability, validity, and sensitivity. Sensitivity index was obtained from the ratio between the smallest worthwhile change and typical error. Results: The TT5km showed high absolute (coefficient of variation < 3%) and relative (intraclass coefficient correlation > 0.95) reliability of performance variables, whereas it presented low reliability of physiological responses. The TT5km performance variables were highly correlated with the aerobic endurance indices obtained from incremental test (r > 0.70). These variables showed adequate sensitivity index (> 1). Conclusions: TT5km is a valid test to rank the aerobic endurance fitness of well-trained cyclists and to differentiate changes on aerobic endurance performance. Coaches can detect performance changes through either absolute (± 17.7 W) or relative power output (± 0.3 W.kg-1), the time to complete the test (± 13.4 s) and the average speed (± 1.0 km.h-1). Furthermore, TT5km performance can also be used to rank the athletes according to their aerobic endurance fitness. PMID:26448846

  6. PROPERTIES OF THE DISTANT KUIPER BELT: RESULTS FROM THE PALOMAR DISTANT SOLAR SYSTEM SURVEY

    SciTech Connect

    Schwamb, Megan E.; Brown, Michael E.; Rabinowitz, David L.; Ragozzine, Darin

    2010-09-10

    We present the results of a wide-field survey using the 1.2 m Samuel Oschin Telescope at Palomar Observatory. This survey was designed to find the most distant members of the Kuiper Belt and beyond. We searched {approx}12,000 deg{sup 2} down to a mean limiting magnitude of 21.3 in R. A total number of 52 Kuiper Belt objects and Centaurs have been detected, 25 of which were discovered in this survey. Except for the redetection of Sedna, no additional Sedna-like bodies with perihelia greater than 45 AU were detected despite sensitivity out to distances of 1000 AU. We discuss the implications for a distant Sedna-like population beyond the Kuiper Belt, focusing on the constraints we can place on the embedded stellar cluster environment the early Sun may be have been born in, where the location and distribution of Sedna-like orbits sculpted by multiple stellar encounters is indicative of the birth cluster size. We also report our observed latitude distribution and implications for the size of the plutino population.

  7. Studies of extra-solar Oort Clouds and the Kuiper Disk

    NASA Technical Reports Server (NTRS)

    Stern, S. Alan

    1994-01-01

    The March 1994 Semi-Annual report for Studies of Extra-Solar Oort Clouds and the Kuiper Disk is presented. We are conducting research designed to enhance our understanding of the evolution and detectability of comet clouds and disks. This area holds promise for also improving our understanding of outer solar system formation, the bombardment history of the planets, the transport of volatiles and organics from the outer solar system to the inner planets, and to the ultimate fate of comet clouds around the Sun and other stars. According to 'standard' theory, both the Kuiper Disk and Oort Cloud are (at least in part) natural products of the planetary accumulation stage of solar system formation. One expects such assemblages to be a common attribute of other solar systems. Therefore, searches for comet disks and clouds orbiting other stars offer a new method for inferring the presence of planetary systems. Our three-year effort consists of two major efforts: observational work to predict and search for the signatures of Oort Clouds and comet disks around other stars; and modeling studies of the formation and evolution of the Kuiper Disk (KD) and similar assemblages that may reside around other stars, including beta Pic.

  8. The Phase Space Structure Near Neptune Resonances in the Kuiper Belt

    NASA Technical Reports Server (NTRS)

    Malhotra, Renu

    1996-01-01

    The Solar system beyond Neptune is believed to house a population of small primordial bodies left over from the planet formation process. The region up to heliocentric distance -50 AU (a.k.a. the Kuiper Belt) may be the source of the observed short-period comets. In this region, the phase space structure near orbital resonances with Neptune is of special interest for the long-term stability of orbits. There is reason to believe that a significant fraction (perhaps most) of the Kuiper Belt objects reside preferentially in these resonance locations. This paper describes the dynamics of small objects near the major orbital resonances with Neptune. Estimates of the widths of stable resonance zones as well as the properties of resonant orbits are obtained from the circular, planar restricted three-body model. Although this model does not contain the full complexity of the long-term orbital dynamics of Kuiper Belt objects subject to the full N-body perturbations of all the planets, it does provide a baseline for the phase space structure and properties of resonant orbits in the trans-Neptunian Solar system.

  9. Formation of Kuiper-belt binaries by dynamical friction and three-body encounters.

    PubMed

    Goldreich, Peter; Lithwick, Yoram; Sari, Re'em

    2002-12-12

    The Kuiper belt is a disk of icy bodies that orbit the Sun beyond Neptune; the largest known members are Pluto and its companion Charon. A few per cent of Kuiper-belt bodies have recently been found to be binaries with wide separations and mass ratios of the order of unity. Collisions were too infrequent to account for the observed number of binaries, implying that these binaries formed through collisionless interactions mediated by gravity. These interactions are likely to have been most effective during the period of runaway accretion, early in the Solar System's history. Here we show that a transient binary forms when two large bodies penetrate one another's Hill sphere (the region where their mutual forces are larger than the tidal force of the Sun). The loss of energy needed to stabilize the binary orbit can then occur either through dynamical friction from surrounding small bodies, or through the gravitational scattering of a third large body. Our estimates slightly favour the former mechanism. We predict that five per cent of Kuiper-belt objects are binaries with apparent separations greater than 0.2 arcsec, and that most are in tighter binaries or systems of higher multiplicity. PMID:12478286

  10. Searching for Extreme Kuiper Belt Objects and Inner Oort Cloud Objects

    NASA Astrophysics Data System (ADS)

    Sheppard, Scott S.; Trujillo, Chad; Tholen, Dave

    2015-11-01

    Since late 2012 we have been performing the largest and deepest survey for distant solar system objects. In the nearly one thousand square degrees we have covered so far we have discovered the object with the most distant perihelion known (2012 VP113), several extreme Kuiper Belt objects with moderate perihelia and large eccentricities, one of the top ten intrinsically brightest Trans-Neptunian objects, an ultra-wide Kuiper Belt binary, one of the most distant known active comets and two active asteroids in the main belt of asteroids. The Kuiper Belt population has an outer edge at about 50 AU. Sedna and our recent discovery, 2012 VP113, are the only known objects with perihelia significantly beyond this edge at about 80 AU. These inner Oort cloud objects obtained their orbits when the solar system was vastly different from now. Thus the dynamical and physical properties of objects in this region offer key constraints on the formation and evolution of our solar system. We will discuss the most recent results of our survey.

  11. Studies of extra-solar OORT clouds and the Kuiper disk

    NASA Technical Reports Server (NTRS)

    Stern, S. Alan

    1993-01-01

    This is the second report for NAGW-3023, Studies of Extra-Solar Oort Clouds and the Kuiper Disk. We are conducting research designed to enhance our understanding of the evolution and detectability of comet clouds and disks. This area holds promise for also improving our understanding of outer solar system formation, the bombardment history of the planets, the transport of volatiles and organics from the outer solar system to the inner planets, and the ultimate fate of comet clouds around the Sun and other stars. According to 'standard' theory, both the Kuiper Disk and Oort Cloud are (at least in part) natural products of the planetary accumulation stage of solar system formation. One expects such assemblages to be a common attribute of other solar systems. Therefore, searches for comet disks and clouds orbiting other stars offer a new method for infering the presence of planetary systems. Our three-year effort consists of two major efforts: (1) observational work to predict and search for the signatures of Oort Clouds and comet disks around other stars; and (2) modelling studies of the formation and evolution of the Kuiper Disk (KD) and similar assemblages that may reside around other stars, including Beta Pic. These efforts are referred to as Task 1 and 2, respectively.

  12. Studies of extra-solar Oort Clouds and the Kuiper Disk

    NASA Technical Reports Server (NTRS)

    Stern, Alan

    1995-01-01

    This is the September 1995 Semi-Annual report for Studies of Extra-Solar Oort Clouds and the Kuiper Disk. We are conducting research designed to enhance our understanding of the evolution and detectability of comet clouds and disks. This area holds promise for also improving our understanding of outer solar system formation the bombardment history of the planets, the transport of volatiles and organics from the outer solar system to the inner planets, and to the ultimate fate of comet clouds around the Sun and other stars. According to 'standard' theory, both the Kuiper Disk and the Oort Cloud are (at least in part) natural products of the planetary accumulation stage of solar system formation. One expects such assemblages to be a common attribute of other solar systems. Therefore, searches for comet disks and clouds orbiting other stars offer a new method for inferring the presence of planetary systems. This project consists of two major efforts: (1) observational work to predict and search for the signatures of Oort Clouds and comet disks around other stars; and (2) modelling studies of the formation and evolution of the Kuiper Disk (KD) and similar assemblages that may reside around other stars, including beta Pic. These efforts are referred to as Task 1 and 2.

  13. Optical Colors of Centaurs and Kuiper Belt Objects From the Keck I 10-m Telescope and the University of Arizona 2.3-m Telescope

    NASA Astrophysics Data System (ADS)

    Tegler, S. C.; Romanishin, W.

    2002-09-01

    Our ongoing survey of Centaur and Kuiper belt object colors includes accurate B-V and V-R colors for about 50 objects. We find 20 out of 20 classical KBOs on low eccentricity and low inclination orbits with perihelion distances, q, greater than 40 AU exhibit extremely red surface colors (Tegler and Romanishin, 2000, Nature, 407, 979; Tegler and Romanishin, 2002, Icarus, submitted). As a result of three nights on the Keck I telescope during April of 2002 and three nights on the 2.3-m telescope during September of 2001, we report B-V and V-R colors for additional Centaurs and KBOs, all with q < 40 AU. We use these latest measurements to test our controversial claim that objects with q < 40 AU divide into two color populations. We thank the NASA Planetary Astronomy Program for their support and the NASA/Keck and University of Arizona TACs for their consistent allocation of telescope time.

  14. Sub-Kilometer Asteroid Diameter Survey (SKADS) V1.0

    NASA Astrophysics Data System (ADS)

    Gladman, B. J.; Davis, D. R.; Neese, C.; Jedicke, R.; Williams, G.; Kavelaars, J. J.; Petit, J.-M.; Scholl, H.; Holman, M.; Warrington, B.; Esquerdo, G.; Tricarico, P.

    2010-05-01

    The Sub-Kilometer Asteroid Diameter Survey (SKADS) (Gladman et al. 2009) acquired good-quality orbital and absolute magnitude (H) determinations for a sample of small main-belt asteroids in order to study the orbital and size distribution beyond H = 15, down to sub-kilometer sizes (H > 18). Based on six observing nights over an 11-night baseline, SKADS detected, measured photometry for, and linked observations of 1087 asteroids which have one-week time baselines or more. This data set contains the astrometry, photometry, and orbits of the 1087 asteroids detected by SKADS.

  15. 2007 TY430: A COLD CLASSICAL KUIPER BELT TYPE BINARY IN THE PLUTINO POPULATION

    SciTech Connect

    Sheppard, Scott S.; Ragozzine, Darin; Trujillo, Chadwick

    2012-03-15

    Kuiper Belt object 2007 TY430 is the first wide, equal-sized, binary known in the 3:2 mean motion resonance with Neptune. The two components have a maximum separation of about 1 arcsec and are on average less than 0.1 mag different in apparent magnitude with identical ultra-red colors (g - i = 1.49 {+-} 0.01 mag). Using nearly monthly observations of 2007 TY430 from 2007 to 2011, the orbit of the mutual components was found to have a period of 961.2 {+-} 4.6 days with a semi-major axis of 21000 {+-} 160 km and eccentricity of 0.1529 {+-} 0.0028. The inclination with respect to the ecliptic is 15.68 {+-} 0.22 deg and extensive observations have allowed the mirror orbit to be eliminated as a possibility. The total mass for the binary system was found to be 7.90 {+-} 0.21 Multiplication-Sign 10{sup 17} kg. Equal-sized, wide binaries and ultra-red colors are common in the low-inclination 'cold' classical part of the Kuiper Belt and likely formed through some sort of three-body interactions within a much denser Kuiper Belt. To date 2007 TY430 is the only ultra-red, equal-sized binary known outside of the classical Kuiper Belt population. Numerical simulations suggest 2007 TY430 is moderately unstable in the outer part of the 3:2 resonance and thus 2007 TY430 is likely an escaped 'cold' classical object that later got trapped in the 3:2 resonance. Similar to the known equal-sized, wide binaries in the cold classical population, the binary 2007 TY430 requires a high albedo and very low density structure to obtain the total mass found for the pair. For a realistic minimum density of 0.5 g cm{sup -3} the albedo of 2007 TY430 would be greater than 0.17. For reasonable densities, the radii of either component should be less than 60 km, and thus the relatively low eccentricity of the binary is interesting since no tides should be operating on the bodies at their large distances from each other. The low prograde inclination of the binary also makes it unlikely that the Kozai

  16. 2007 TY430: A Cold Classical Kuiper Belt Type Binary in the Plutino Population

    NASA Astrophysics Data System (ADS)

    Sheppard, Scott S.; Ragozzine, Darin; Trujillo, Chadwick

    2012-03-01

    Kuiper Belt object 2007 TY430 is the first wide, equal-sized, binary known in the 3:2 mean motion resonance with Neptune. The two components have a maximum separation of about 1 arcsec and are on average less than 0.1 mag different in apparent magnitude with identical ultra-red colors (g - i = 1.49 ± 0.01 mag). Using nearly monthly observations of 2007 TY430 from 2007 to 2011, the orbit of the mutual components was found to have a period of 961.2 ± 4.6 days with a semi-major axis of 21000 ± 160 km and eccentricity of 0.1529 ± 0.0028. The inclination with respect to the ecliptic is 15.68 ± 0.22 deg and extensive observations have allowed the mirror orbit to be eliminated as a possibility. The total mass for the binary system was found to be 7.90 ± 0.21 × 1017 kg. Equal-sized, wide binaries and ultra-red colors are common in the low-inclination "cold" classical part of the Kuiper Belt and likely formed through some sort of three-body interactions within a much denser Kuiper Belt. To date 2007 TY430 is the only ultra-red, equal-sized binary known outside of the classical Kuiper Belt population. Numerical simulations suggest 2007 TY430 is moderately unstable in the outer part of the 3:2 resonance and thus 2007 TY430 is likely an escaped "cold" classical object that later got trapped in the 3:2 resonance. Similar to the known equal-sized, wide binaries in the cold classical population, the binary 2007 TY430 requires a high albedo and very low density structure to obtain the total mass found for the pair. For a realistic minimum density of 0.5 g cm-3 the albedo of 2007 TY430 would be greater than 0.17. For reasonable densities, the radii of either component should be less than 60 km, and thus the relatively low eccentricity of the binary is interesting since no tides should be operating on the bodies at their large distances from each other. The low prograde inclination of the binary also makes it unlikely that the Kozai mechanism could have altered the orbit

  17. A SEARCH FOR OCCULTATIONS OF BRIGHT STARS BY SMALL KUIPER BELT OBJECTS USING MEGACAM ON THE MMT

    SciTech Connect

    Bianco, F. B.; Lehner, M. J.; Protopapas, P.; McLeod, B. A.; Alcock, C. R.; Holman, M. J.

    2009-08-15

    We conducted a search for occultations of bright stars by Kuiper Belt Objects (KBOs) to estimate the density of subkilometer KBOs in the sky. We report here the first results of this occultation survey of the outer solar system conducted in 2007 June and 2008 June/July at the MMT Observatory using Megacam, the large MMT optical imager. We used Megacam in a novel shutterless continuous-readout mode to achieve high-precision photometry at 200 Hz, which with point-spread function convolution results in an effective sampling of {approx}30 Hz. We present an analysis of 220 star hours of data at a signal-to-noise ratio of 25 or greater, taken from images of fields within 3 deg. of the ecliptic plane. The survey efficiency is greater than 10% for occultations by KBOs of diameter d {>=} 0.7 km, and we report no detections in our data set. We set a new 95% confidence level upper limit for the surface density {sigma} {sub N}(d) of KBOs larger than 1 km: {sigma} {sub N}(d {>=} 1 km) {<=} 2.0 x 10{sup 8} deg{sup -2}, and for KBOs larger than 0.7 km {sigma} {sub N}(d {>=} 0.7 km) {<=} 4.8 x 10{sup 8} deg{sup -2}.

  18. 47 CFR 73.186 - Establishment of effective field at one kilometer.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Establishment of effective field at one... at one kilometer. (a) Section 73.189 provides that certain minimum field strengths are acceptable in... radiation (not less than one wave length or 5 times the vertical height in the case of a single element,...

  19. Solubility relations in the ternary system NaCl-CsCl-H2O at 1 atm. 1. Solubilities of halite from 20 to 100 °C

    USGS Publications Warehouse

    Chou, I.-Ming; Lee, R.D.

    1983-01-01

    Solubilities of halite in the ternary system NaCl-CsCl-H2O have been determined by the visual polythermal method at 1 atm from 20 to 100??C along five constant CsCl/(CsCl + H2O) weight ratio lines. These five constant weight ratios are 0.1, 0.2, 0.3, 0.4, and 0.5. The maximum uncertainties in these measurements are ??0.02 wt % NaCl and ??0.15??C. The data along each constant CsCl/(CsCl + H2O) weight ratio line were regressed to a smooth curve. The maximum deviation of the measured solubilities from the smooth curves is 0.06 wt % NaCl. Isothermal solubilities of halite were calculated from smoothed curves at 25, 50, and 75??C.

  20. Fast electron production in collisions of swift heavy ions (20 MeV/ u < E < 100 MeV/ u) with foils of solids

    NASA Astrophysics Data System (ADS)

    Lanzanò, G.; De Filippo, E.; Rothard, H.; Volant, C.; Anzalone, A.; Arena, N.; Geraci, M.; Giustolisi, F.; Pagano, A.

    2005-05-01

    In nuclear and atomic experiments at high incident ion energies, 20 MeV/ u < E < 100 MeV/ u, the impact of swift heavy ions on thin solid targets is a source of fast electrons. The knowledge of their spatial and kinematical distributions is very useful for experimental nuclear and radiobiological applications as well as testing atomic ionization theories. An overview on the main mechanisms underlying the production of the electrons is given. Some recent results obtained at the Catania LNS superconducting cyclotron, mainly with a 45 MeV/ u58Ni 19+ beam are shown. In particular, the production and the properties of binary encounter-, convoy-, in-flight Auger- and backward emitted electrons are discussed.

  1. Dynamics of the Trans-Neptune Region: Apsidal Waves in the Kuiper Belt

    NASA Technical Reports Server (NTRS)

    Ward, William R.; Hahn, Joseph M.

    1998-01-01

    The role of apsidal density waves propagating in a primordial trans-Neptune disk (i.e., Kuiper belt) is investigated. It is shown that Neptune launches apsidal waves at its secular resonance near 40 AU that propagate radially outward, deeper into the particle disk. The wavelength of apsidal waves is considerably longer than waves that might be launched at Lindblad resonances, because the pattern speed, g(sub s), resulting from the apsis precession of Neptune is much slower than its mean motion, Omega(sub s). If the early Kuiper belt had a sufficient surface density, sigma, the disk's wave response to Neptune's secular perturbation would have spread the disturbing torque radially over a collective scale lambda(sub *) approx. = r(2(mu)(sub d)Omega/ absolute value of r dg/dr)(sup 1/2), where mu(sub d)equivalent pi(sigma)r(exp 2)/(1 solar mass) and Omega(r) and g(r) are respectively the mean motion and precession frequency of the disk particles. This results in considerably smaller eccentricities at resonance than had the disk particles been treated as noninteracting test particles. Consequently, particles are less apt to be excited into planet-crossing orbits, implying that the erosion timescales reported by earlier test-particle simulations of the Kuiper belt may be underestimated. It is also shown that the torque the disk exerts upon the planet (due to its gravitational attraction for the disk's spiral wave pattern) damps the planet's eccentricity and further inhibits the planet's ability to erode the disk. Key words: celestial mechanics, stellar dynamics - comets: general minor planets, asteroids

  2. A Magnitude Limited Survey of the Rotational Properties of Kuiper Belt Objects

    NASA Astrophysics Data System (ADS)

    Kokotanekova, R.; Lacerda, P.; Snodgrass, C.; Lockhart, M.; Lorek, S.; Peixinho, N.; Thirouin, A.; Carry, B.; Davidsson, B.; Fornasier, S.; Wyatt, M.; Hainaut, O.

    2015-10-01

    We will present the first results from a magnitudelimited survey of over 60 Kuiper belt objects (KBOs) observed within a Large Program at the 3.6-m ESO New Technology Telescope (NTT). The multi-band observations are used to obtain lightcurves for targets from all KBO dynamical classes. We are aiming to derive the individual targets' physical and rotational characteristics as well as to use the bulk properties of the different KBO populations as sources of information for their formation mechanisms and collisional history.

  3. Water Ice in 2060 Chiron and Its Implications for Centaurs and Kuiper Belt Objects.

    PubMed

    Luu; Jewitt; Trujillo

    2000-03-10

    We report the detection of water ice in the Centaur 2060 Chiron, based on near-infrared spectra (1.0-2.5 µm) taken with the 3.8 m United Kingdom Infrared Telescope and the 10 m Keck Telescope. The appearance of this ice is correlated with the recent decline in Chiron's cometary activity: the decrease in the coma cross section allows previously hidden solid-state surface features to be seen. We predict that water ice is ubiquitous among Centaurs and Kuiper Belt objects, but its surface coverage varies from object to object and thus determines its detectability and the occurrence of cometary activity. PMID:10688775

  4. The evolution of comets in the Oort cloud and Kuiper belt.

    PubMed

    Alan Stern, S

    2003-08-01

    Comets are remnants from the time when the outer planets formed, approximately 4-4.5 billion years ago. They have been in storage since then in the Oort cloud and Kuiper belt-distant regions that are so cold and sparsely populated that it was long thought that comets approaching the Sun were pristine samples from the time of Solar System formation. It is now recognized, however, that a variety of subtle but important evolutionary mechanisms operate on comets during their long storage, so they can no longer be regarded as wholly pristine. PMID:12904784

  5. Observational Constraints on n>2 Multiples in the Kuiper Belt

    NASA Astrophysics Data System (ADS)

    Noll, K. S.

    2006-12-01

    The discovery of two small satellites of the Pluto-Charon binary (Weaver et al. 2006, Nature 439, 943) clearly demonstrates that complex multiples can and do exist among the population of transneptunian objects. The discovery of a second companion to the main belt asteroid (87) Sylvia establishes the same existence proof for the inner solar system (Marchis et al. 2005, Nature 436, 822). The mode of formation for binaries and multiples remains to be unambiguously identified for any small body population in the solar system. Collisional models of binary formation show that some fraction of triples and higher order multiples can be expected to form as a natural consequence of chance capture of impact debris (Leinhardt and Richardson 2005, Icarus 176, 432). However, these models cannot be used to accurately predict the fraction of such systems in the absence of observational constraints. Likewise, capture models can, in principle, produce multiples, but quantitative work on this question has not been done. The large survey that we are carrying out with the Hubble Space Telescope is providing the most stringent observational constraints on the frequencies of binaries and higher order multiples to date. Of the roughly 20 binaries observed with the ACS/HRC, none has been found to have a third companion. The limits vary with the observations, but, generally speaking, most of the observations search several magnitudes fainter than the primary at separations of 50 milliarcsec or more. Future observations with HST have the capability to increase this limit by an order of magnitude by increasing the sample of known binaries.

  6. Constraints on impact rates in the pluto-charon system and the population of the Kuiper comet belt

    SciTech Connect

    Weissman, P.R. ); Dobrovolskis, A.R. ); Stern, S.A. )

    1989-11-01

    Impact rates in the Pluto-Charon system are dominated by comets from the proposed Kuiper Belt, 30 to 50 AU from the Sun. Such collisions excite the eccentricity of Charon's orbit, which then decays due to tidal dissipation. Charon's eccentricity approaches a quasi-steady state, which can be used to constrain the total number and mass of comets in the Kuiper Belt. Unfortunately, the current upper limit on Charon's orbital eccentricity must be reduced by more than a factor of ten before useful constraints can be set.

  7. Constraints on impact rates in the Pluto-Charon system and the population of the Kuiper comet belt

    NASA Technical Reports Server (NTRS)

    Weissman, Paul R.; Dobrovolskis, Anthony R.; Stern, S. Alan

    1989-01-01

    Impact rates in the Pluto-Charon system are dominated by comets from the proposed Kuiper Belt, 30 to 50 AU from the sun. Such collisions excite the eccentricity of Charon's orbit, which then decays due to tidal dissipation. Charon's eccentricity approaches a quasi-steady state, which can be used to constrain the total number and mass of comets in the Kuiper Belt. Unfortunately, the current upper limit on Charon's orbital eccentricity must be reduced by more than a factor of ten before useful constraints can be set.

  8. Origin of the peculiar eccentricity distribution of the inner cold Kuiper belt

    NASA Astrophysics Data System (ADS)

    Morbidelli, A.; Gaspar, H. S.; Nesvorny, D.

    2014-04-01

    Dawson and Murray-Clay (Dawson and Murray-Clay [2012]. Astrophys. J., 750, 43) pointed out that the inner part of the cold population in the Kuiper belt (that with semi major axis a<43.5 AU) has orbital eccentricities significantly smaller than the limit imposed by stability constraints. Here, we confirm their result by looking at the orbital distribution and stability properties in proper element space. We show that the observed distribution could have been produced by the slow sweeping of the 4/7 mean motion resonance with Neptune that accompanied the end of Neptune’s migration process. The orbital distribution of the hot Kuiper belt is not significantly affected in this process, for the reasons discussed in the main text. Therefore, the peculiar eccentricity distribution of the inner cold population cannot be unequivocally interpreted as evidence that the cold population formed in situ and was only moderately excited in eccentricity; it can simply be the signature of Neptune’s radial motion, starting from a moderately eccentric orbit. We discuss how this agrees with a scenario of giant planet evolution following a dynamical instability and, possibly, with the radial transport of the cold population.

  9. Size and albedo of Kuiper belt object 55636 from a stellar occultation.

    PubMed

    Elliot, J L; Person, M J; Zuluaga, C A; Bosh, A S; Adams, E R; Brothers, T C; Gulbis, A A S; Levine, S E; Lockhart, M; Zangari, A M; Babcock, B A; Dupré, K; Pasachoff, J M; Souza, S P; Rosing, W; Secrest, N; Bright, L; Dunham, E W; Sheppard, S S; Kakkala, M; Tilleman, T; Berger, B; Briggs, J W; Jacobson, G; Valleli, P; Volz, B; Rapoport, S; Hart, R; Brucker, M; Michel, R; Mattingly, A; Zambrano-Marin, L; Meyer, A W; Wolf, J; Ryan, E V; Ryan, W H; Morzinski, K; Grigsby, B; Brimacombe, J; Ragozzine, D; Montano, H G; Gilmore, A

    2010-06-17

    The Kuiper belt is a collection of small bodies (Kuiper belt objects, KBOs) that lie beyond the orbit of Neptune and which are believed to have formed contemporaneously with the planets. Their small size and great distance make them difficult to study. KBO 55636 (2002 TX(300)) is a member of the water-ice-rich Haumea KBO collisional family. The Haumea family are among the most highly reflective objects in the Solar System. Dynamical calculations indicate that the collision that created KBO 55636 occurred at least 1 Gyr ago. Here we report observations of a multi-chord stellar occultation by KBO 55636, which occurred on 9 October 2009 ut. We find that it has a mean radius of 143 +/- 5 km (assuming a circular solution). Allowing for possible elliptical shapes, we find a geometric albedo of in the V photometric band, which establishes that KBO 55636 is smaller than previously thought and that, like its parent body, it is highly reflective. The dynamical age implies either that KBO 55636 has an active resurfacing mechanism, or that fresh water-ice in the outer Solar System can persist for gigayear timescales. PMID:20559381

  10. Size and albedo of Kuiper belt object 55636 from a stellar occultation

    NASA Astrophysics Data System (ADS)

    Elliot, J. L.; Person, M. J.; Zuluaga, C. A.; Bosh, A. S.; Adams, E. R.; Brothers, T. C.; Gulbis, A. A. S.; Levine, S. E.; Lockhart, M.; Zangari, A. M.; Babcock, B. A.; Dupré, K.; Pasachoff, J. M.; Souza, S. P.; Rosing, W.; Secrest, N.; Bright, L.; Dunham, E. W.; Sheppard, S. S.; Kakkala, M.; Tilleman, T.; Berger, B.; Briggs, J. W.; Jacobson, G.; Valleli, P.; Volz, B.; Rapoport, S.; Hart, R.; Brucker, M.; Michel, R.; Mattingly, A.; Zambrano-Marin, L.; Meyer, A. W.; Wolf, J.; Ryan, E. V.; Ryan, W. H.; Morzinski, K.; Grigsby, B.; Brimacombe, J.; Ragozzine, D.; Montano, H. G.; Gilmore, A.

    2010-06-01

    The Kuiper belt is a collection of small bodies (Kuiper belt objects, KBOs) that lie beyond the orbit of Neptune and which are believed to have formed contemporaneously with the planets. Their small size and great distance make them difficult to study. KBO 55636 (2002 TX300) is a member of the water-ice-rich Haumea KBO collisional family. The Haumea family are among the most highly reflective objects in the Solar System. Dynamical calculations indicate that the collision that created KBO 55636 occurred at least 1Gyr ago. Here we report observations of a multi-chord stellar occultation by KBO 55636, which occurred on 9 October 2009 UT. We find that it has a mean radius of 143+/-5km (assuming a circular solution). Allowing for possible elliptical shapes, we find a geometric albedo of in the V photometric band, which establishes that KBO 55636 is smaller than previously thought and that, like its parent body, it is highly reflective. The dynamical age implies either that KBO 55636 has an active resurfacing mechanism, or that fresh water-ice in the outer Solar System can persist for gigayear timescales.

  11. 1998 SM165: A large Kuiper belt object with an irregular shape

    PubMed Central

    Romanishin, W.; Tegler, S. C.; Rettig, T. W.; Consolmagno, G.; Botthof, B.

    2001-01-01

    The recent discovery of an ancient reservoir of icy bodies at and beyond the orbit of Neptune—the Kuiper belt—has opened a new frontier in astronomy. Measurements of the physical and chemical nature of Kuiper belt objects (KBOs) can constrain our ideas of the processes of planet formation and evolution. Our 1.8-m Vatican Advanced Technology Telescope and charge-coupled device camera observations of the KBO 1998 SM165 indicate its brightness periodically varies by 0.56 magnitudes over a 4-h interval. If we assume a uniform albedo of 0.04, which is typical of values found in the literature for a handful of KBOs, and an “equator-on” aspect, we find 1998 SM165 has axes of length 600 × 360 km. If our assumptions are correct, such dimensions put 1998 SM165 among the largest elongated objects known in our solar system. Perhaps long ago, two nearly spherical KBOs of comparable size coalesced to form a compound object, or perhaps 1998 SM165 is the residual core of a catastrophic fragmentation of a larger precursor. PMID:11572937

  12. 1998 SM165: a large Kuiper belt object with an irregular shape.

    PubMed

    Romanishin, W; Tegler, S C; Rettig, T W; Consolmagno, G; Botthof, B

    2001-10-01

    The recent discovery of an ancient reservoir of icy bodies at and beyond the orbit of Neptune-the Kuiper belt-has opened a new frontier in astronomy. Measurements of the physical and chemical nature of Kuiper belt objects (KBOs) can constrain our ideas of the processes of planet formation and evolution. Our 1.8-m Vatican Advanced Technology Telescope and charge-coupled device camera observations of the KBO 1998 SM(165) indicate its brightness periodically varies by 0.56 magnitudes over a 4-h interval. If we assume a uniform albedo of 0.04, which is typical of values found in the literature for a handful of KBOs, and an "equator-on" aspect, we find 1998 SM(165) has axes of length 600 x 360 km. If our assumptions are correct, such dimensions put 1998 SM(165) among the largest elongated objects known in our solar system. Perhaps long ago, two nearly spherical KBOs of comparable size coalesced to form a compound object, or perhaps 1998 SM(165) is the residual core of a catastrophic fragmentation of a larger precursor. PMID:11572937

  13. Experimentally determined density matrices for H( n =3) formed in H sup + -He collisions from 20 to 100 keV

    SciTech Connect

    Ashburn, J.R.; Cline, R.A.; van der Burgt, P.J.M.; Westerveld, W.B.; Risley, J.S. )

    1990-03-01

    Density matrices describing H({ital n}=3) atoms produced in collisions of 20- to 100-keV protons with He atoms have been determined experimentally. In the experiment the intensity and polarization of Balmer-{alpha} radiation emitted from a He gas cell are measured as a function of the strength of an externally applied electric field. Electric fields are applied in a direction either axial to or transverse to the proton beam. Density matrices are extracted by detailed analysis of the optical data. Data are obtained for each field direction and then analyzed, separately and in combination, to yield density matrices. Satisfactory agreement is found between density matrices determined from axial and transverse electric field data except at the lowest energies studied. Some nonzero density-matrix elements are determined more accurately using axial electric fields than with transverse fields, while other elements are more accurately determined using transverse electric fields. The combined analysis using data from both field directions gives a better determination of the density matrix than the separate data sets. Results for the H({ital n}=3) electron-transfer cross sections (relative to 3{ital s}), the electric dipole moment of the charge distribution {l angle}{bold d}{r angle}{sub {ital z}}, a first-order moment of the current distribution {l angle}{bold L}{times}{bold A}{r angle}{sub {ital z},{ital s}}, and the average coherence Tr({sigma}{sub 3}{sup 2}) are obtained. The experimental results are compared to two recent calculations using the augmented atomic orbital (AO+) theory and the continuum distorted-wave approximation with post-collision interaction theory, and to one recent experimental measurement of the diagonal density-matrix elements. Both theories show qualitative agreement with the general trends in the data. The AO+ method gives better quantitative agreement.

  14. Photographer : JPL Range : 6.5 million kilometers (4 million miles) Six violet images of Jupiter

    NASA Technical Reports Server (NTRS)

    1979-01-01

    Photographer : JPL Range : 6.5 million kilometers (4 million miles) Six violet images of Jupiter makes the mosaic photo, showing the Great Red Spot as a swirling vortex type motion. This motion is also seen in several nearby white clouds. These bright white clouds and the Red Spot are rotating in a counter clockwise direction, except the peculiar filimentary cloud to the right of the Red Spot is going clockwise. The top of the picture shows the turbulence from the equatorial jet and more northerly atmospheric currents. The smallest clouds shown are only 70 miles (120 km) across.

  15. Effective matrix diffusion in kilometer-scale transport in fractured crystalline rock

    USGS Publications Warehouse

    Shapiro, A.M.

    2001-01-01

    Concentrations of tritium (3H) and dichlorodifluoromethane (CFC-12) in water samples taken from glacial drift and fractured crystalline rock over 4 km2 in central New Hampshire are interpreted to identify a conceptual model of matrix diffusion and the magnitude of the diffusion coefficient. Dispersion and mass transfer to and from fractures has affected the 3H concentration to the extent that the peak 3H concentration of the 1960s is no longer distinguishable. Because of heterogeneity in the bedrock the sparsely distributed chemical data do not warrant a three-dimensional transport model. Instead, a one-dimensional model of CFC-12 and 3H migration along flow lines in the glacial drift and bedrock is used to place bounds on the processes affecting kilometer-scale transport, and model parameters are varied to reproduce the measured relation between 3H and CFC-12, rather than their spatial distributions. A model of mass exchange to and from fractures that is dependent on the time-varying concentration gradient at fracture surfaces qualitatively reproduces the measured relation between 3H and CFC-12 with an upper bound for the fracture dispersivity approximately equal to 250 m and a lower bound for the effective matrix diffusion coefficient equal to 1 m2 yr-1. The diffusion coefficient at the kilometer scale is at least 3 orders of magnitude greater than laboratory estimates of diffusion in crystalline rock. The large diffusion coefficient indicates that diffusion into an immobile fluid phase (rock matrix) is masked at the kilometer scale by advective mass exchange between fractures with large contrasts in transmissivity. The measured transmissivity of fractures in the study area varies over more than 6 orders of magnitude. Advective mass exchange from high-permeability fractures to low-permeability fractures results in short migration distances of a chemical constituent in low-permeability fractures over an extended period of time before reentering high

  16. Enhancement of cation diffusion rates across the 410-kilometer discontinuity in Earth's mantle

    PubMed

    Chakraborty; Knoche; Schulze; Rubie; Dobson; Ross; Angel

    1999-01-15

    Rates of cation diffusion (magnesium, iron, and nickel) have been determined in olivine and its high-pressure polymorph, wadsleyite, at 9 to 15 gigapascals and 1100 degrees to 1400 degreesC for compositions that are relevant to Earth's mantle. Diffusion in olivine becomes strongly dependent on composition at high pressure. In wadsleyite, diffusion is one to two orders of magnitude faster than in olivine, depending on temperature. Homogenization of mantle heterogeneities (chemical mixing) and mineral transformations involving a magnesium-iron exchange will therefore occur considerably faster in the transition zone than at depths of less than 410 kilometers. PMID:9888846

  17. Seismic evidence for olivine phase changes at the 410- and 660-kilometer discontinuities.

    PubMed

    Lebedev, Sergei; Chevrot, Sébastien; van der Hilst, Rob D

    2002-05-17

    The view that the seismic discontinuities bounding the mantle transition zone at 410- and 660-kilometer depths are caused by isochemical phase transformations of the olivine structure is debated. Combining converted-wave measurements in East Asia and Australia with seismic velocities from regional tomography studies, we observe a correlation of the thickness of, and wavespeed variations within, the transition zone that is consistent with olivine structural transformations. Moreover, the seismologically inferred Clapeyron slopes are in agreement with the mineralogical Clapeyron slopes of the (Mg,Fe)2SiO4 spinel and postspinel transformations. PMID:12016311

  18. Evidence for 115 kilometers of right slip on the san gregorio-hosgri fault trend.

    PubMed

    Graham, S A; Dickinson, W R

    1978-01-13

    The San Gregorio-Hosgri fault trend is a component of the San Andreas fault system on which there may have been about 115 kilometers of post-early Miocene right-lateral strike slip. If so, right slip on the San Andreas and San Gregorio-Hosgri faults accounts for most of the movement between the Pacific and North American plates since mid-Miocene time. Furthermore, the magnitude of right slip on a Paleogene proto-San Andreas fault inferred from the present distribution of granitic basement is reduced considerably when Neogene-Recent San Gregorio-Hosgri right slip is taken into account. PMID:17812950

  19. Broad Perspectives on Mars Landing Site Selection: Geological Factors from Centimeter to Kilometer Scales

    NASA Technical Reports Server (NTRS)

    Jakosky, B. M.; Golombek, M. P.

    2001-01-01

    Selection of a landing site for the '03 and later Mars surface missions represents a balance between potential science results and landing site safety. Although safety has to be the prime consideration, it is the melding together of spacecraft hazard analysis with science analysis that provides the key to understanding the nature of the surface for determining both its safety for landing and its scientific potential. Our goal here is to discuss the geological factors that go into a determination of site safety, at scales from centimeters up to kilometers, and to understand the implications for the resulting scientific return that can be expected.

  20. Photographer : JPL Range : 6 million kilometers (3.7 million miles) Central Longitude 120 degrees

    NASA Technical Reports Server (NTRS)

    1979-01-01

    Photographer : JPL Range : 6 million kilometers (3.7 million miles) Central Longitude 120 degrees west, North is up. and 3rd from the planet. Photo taken after midnight Ganymede is slightly larger than Mercury but much less dense (twice the density of water). Its surface brightness is 4 times of Earth's Moon. Mare regions (dark features) are like the Moon's but have twice the brightness, and believed to be unlikely of rock or lava as the Moon's are. It's north pole seems covered with brighter material and may be water frost. Scattered brighter spots may be related to impact craters or source of fresh ice.

  1. INITIAL PLANETESIMAL SIZES AND THE SIZE DISTRIBUTION OF SMALL KUIPER BELT OBJECTS

    SciTech Connect

    Schlichting, Hilke E.; Fuentes, Cesar I.; Trilling, David E.

    2013-08-01

    The Kuiper Belt is a remnant from the early solar system and its size distribution contains many important constraints that can be used to test models of planet formation and collisional evolution. We show, by comparing observations with theoretical models, that the observed Kuiper Belt size distribution is well matched by coagulation models, which start with an initial planetesimal population with radii of about 1 km, and subsequent collisional evolution. We find that the observed size distribution above R {approx} 30 km is primordial, i.e., it has not been modified by collisional evolution over the age of the solar system, and that the size distribution below R {approx} 30 km has been modified by collisions and that its slope is well matched by collisional evolution models that use published strength laws. We investigate in detail the resulting size distribution of bodies ranging from 0.01 km to 30 km and find that its slope changes several times as a function of radius before approaching the expected value for an equilibrium collisional cascade of material strength dominated bodies for R {approx}< 0.1 km. Compared to a single power-law size distribution that would span the whole range from 0.01 km to 30 km, we find in general a strong deficit of bodies around R {approx} 10 km and a strong excess of bodies around 2 km in radius. This deficit and excess of bodies are caused by the planetesimal size distribution left over from the runaway growth phase, which left most of the initial mass in small planetesimals while only a small fraction of the total mass is converted into large protoplanets. This excess mass in small planetesimals leaves a permanent signature in the size distribution of small bodies that is not erased after 4.5 Gyr of collisional evolution. Observations of the small Kuiper Belt Object (KBO) size distribution can therefore test if large KBOs grew as a result of runaway growth and constrained the initial planetesimal sizes. We find that results from

  2. THE COLOR DIFFERENCES OF KUIPER BELT OBJECTS IN RESONANCE WITH NEPTUNE

    SciTech Connect

    Sheppard, Scott S.

    2012-12-01

    The optical colors of 58 objects in mean motion resonance with Neptune were obtained. The various Neptune resonant populations were found to have significantly different surface color distributions. The 5:3 and 7:4 resonances have semimajor axes near the middle of the main Kuiper Belt and both are dominated by ultra-red material (spectral gradient: S {approx}> 25). The 5:3 and 7:4 resonances have statistically the same color distribution as the low-inclination 'cold' classical belt. The inner 4:3 and distant 5:2 resonances have objects with mostly moderately red colors (S {approx} 15), similar to the scattered and detached disk populations. The 2:1 resonance, which is near the outer edge of the main Kuiper Belt, has a large range of colors with similar numbers of moderately red and ultra-red objects at all inclinations. The 2:1 resonance was also found to have a very rare neutral colored object showing that the 2:1 resonance is really a mix of all object types. The inner 3:2 resonance, like the outer 2:1, has a large range of objects from neutral to ultra-red. The Neptune Trojans (1:1 resonance) are only slightly red (S {approx} 9), similar to the Jupiter Trojans. The inner 5:4 resonance only has four objects with measured colors but shows equal numbers of ultra-red and moderately red objects. The 9:5, 12:5, 7:3, 3:1, and 11:3 resonances do not have reliable color distribution statistics since few objects have been observed in these resonances, though it appears noteworthy that all three of the measured 3:1 objects have only moderately red colors, similar to the 4:3 and 5:2 resonances. The different color distributions of objects in mean motion resonance with Neptune are likely a result from the disruption of the primordial Kuiper Belt from the scattering and migration of the giant planets. The few low-inclination objects known in the outer 2:1 and 5:2 resonances are mostly only moderately red. This suggests if the 2:1 and 5:2 have a cold low-inclination component

  3. Magnetic conjugate point observations of kilometer and hundred-meter scale irregularities and zonal drifts

    NASA Astrophysics Data System (ADS)

    de Paula, E. R.; Muella, M. T. A. H.; Sobral, J. H. A.; Abdu, M. A.; Batista, I. S.; Beach, T. L.; Groves, K. M.

    2010-08-01

    The Conjugate Point Equatorial Experiment (COPEX) campaign was carried out in Brazil, between October and December 2002, to study the conjugate nature of plasma bubble irregularities and to investigate their generation mechanisms, development characteristics, spatial-temporal distribution, and dynamics. In this work we will focus mainly on the zonal spaced GPS (1.575 GHz) and VHF (250 MHz) receivers' data collected simultaneously at two magnetic conjugate sites of the COPEX geometry: Boa Vista and Campo Grande. These GPS/VHF receivers were set up to detect the equatorial scintillations and to measure ionospheric scintillation pattern velocities. Then, the zonal irregularity drift velocities were estimated by applying a methodology that corrects the effects caused by vertical drifts and geometrical factors. The results reveal the coexistence of kilometer- (VHF) and hundred-meter-scale (GPS L-band) irregularities into the underlying depletion structure. Over the conjugate site of Campo Grande, the average zonal velocity at VHF seems to be consistently larger than the estimated GPS velocities until ˜0200 UT, whereas over Boa Vista the irregularities detected from both techniques are drifting with comparable velocities. The hundred-meter-scale structures causing L-band scintillations appear to be drifting with comparable velocities over both the conjugate sites, whereas the kilometer-scale structures are drifting over Campo Grande with larger average velocities (before 0300 UT). Complementary data of ionospheric parameters scaled from collocated digital ionosondes are used in the analysis to explain differences/similarities on the scintillation/zonal drift results.

  4. The Inchworm Deep Drilling System for Kilometer Scale Subsurface Exploration of Europa (IDDS)

    NASA Astrophysics Data System (ADS)

    Rafeek, S.; Gorevan, S. P.; Bartlett, P. W.; Kong, K. Y.

    2001-01-01

    The Inchworm Deep Drilling System (IDDS) is a compact subsurface transport system capable of accessing regions of astrobiological interest deep below the surface of Jupiter's moon, Europa. The IDDS answers Focus Investigation Area 1 as an innovative concept for implementing subsurface exploration of Europa. The concept is being developed at Honeybee Robotics to reach depths on the order of one kilometer with no tether or umbilical of any kind. The device's unique, inchworm-burrowing method appears capable of achieving this near-term depth goal and it is foreseeable that the IDDS will be capable of autonomously drilling to tens of kilometers below the surface. Logical applications of the concept also include accessing the proposed subsurface oceans on Ganymede and Callisto, subsurface water ice on Mars, and Lake Vostok on Earth. The conference presentation will communicate the IDDS concept and how it can enable the search for prebiotic and biotic chemical processes on Europa by bringing proper instrumentation to the subsurface ocean for in-situ investigation and/or returning samples to the surface. Currently, a proposal for breadboarding the IDDS is pending for the Research Opportunities for Space Science's Astrobiology Science and Technology Instrument Development NRA. Additional information is contained in the original extended abstract.

  5. A FEATURE MOVIE OF SiO EMISSION 20-100 AU FROM THE MASSIVE YOUNG STELLAR OBJECT ORION SOURCE I

    SciTech Connect

    Matthews, L. D.; Greenhill, L. J.; Goddi, C.; Humphreys, E. M. L.; Chandler, C. J.; Kunz, M. W.

    2010-01-01

    We present multi-epoch Very Long Baseline Array imaging of the {sup 28}SiO v = 1 and v = 2, J = 1-0 maser emission toward the massive young stellar object (YSO) Orion Source I. Both SiO transitions were observed simultaneously with an angular resolution of approx0.5 mas (approx0.2 AU for d = 414 pc) and a spectral resolution of approx0.2 km s{sup -1}. Here we explore the global properties and kinematics of the emission through two 19-epoch animated movies spanning 21 months (from 2001 March 19 to 2002 December 10). These movies provide the most detailed view to date of the dynamics and temporal evolution of molecular material within approx20-100 AU of a massive (approx>8 M{sub sun}) YSO. As in previous studies, we find that the bulk of the SiO masers surrounding Source I lie in an X-shaped locus; the emission in the south and east arms is predominantly blueshifted, and emission in the north and west is predominantly redshifted. In addition, bridges of intermediate-velocity emission are observed connecting the red and blue sides of the emission distribution. We have measured proper motions of over 1000 individual maser features and found that these motions are characterized by a combination of radially outward migrations along the four main maser-emitting arms and motions tangent to the intermediate-velocity bridges. We interpret the SiO masers as arising from a wide-angle bipolar wind emanating from a rotating, edge-on disk. The detection of maser features along extended, curved filaments suggests that magnetic fields may play a role in launching and/or shaping the wind. Our observations appear to support a picture in which stars with masses as high as at least 8 M{sub sun} form via disk-mediated accretion. However, we cannot yet rule out that the Source I disk may have been formed or altered following a recent close encounter.

  6. Co1lisional Grooming Models of the Kuiper Belt Dust Cloud

    NASA Technical Reports Server (NTRS)

    Kuchner, Marc

    2010-01-01

    Debris disks around other stars, like the disks around Fomalhaut, Vega, and Epsilon Eridani, are often described as more massive versions of the Kuiper Belt. But for a long time, it's been hard to test this notion, because grain-grain collisions limit the grain lifetimes and we lacked the tools to model the effects of these collisions on the appearance of the disks. I'll describe a new breakthrough that has allowed us to make 3-D models of grain-grain collisions in debris disks for the first time, and I'll show the latest supercomputer simulations of these systems, illustrating how planets and collisions together sculpt the TNO dust.

  7. Real Time Data/Video/Voice Uplink and Downlink for Kuiper Airborne Observatory

    NASA Technical Reports Server (NTRS)

    Harper, Doyal A.

    1997-01-01

    LFS was an educational outreach adventure which brought the excitement of astronomical exploration on NASA's Kuiper Airborne Observatory (KAO) to a nationwide audience of children, parents and children through live, interactive television, broadcast from the KAO at an altitude of 41,000 feet during an actual scientific observing mission. The project encompassed three KAO flights during the fall of 1995, including a short practice mission, a daytime observing flight between Moffett Field, California to Houston, Texas, and a nighttime mission from Houston back to Moffett Field. The University of Chicago infrared research team participated in planning the program, developing auxiliary materials including background information and lesson plans, developing software which allowed students on the ground to control the telescope and on-board cameras via the Internet from the Adler Planetarium in Chicago, and acting as on-camera correspondents to explain and answer questions about the scientific research conducted during the flights.

  8. The Kuiper Belt, Exozodiacal Dust, Debris Disks: It's All About Collisions

    NASA Technical Reports Server (NTRS)

    Kuchner, Marc

    2010-01-01

    Debris disks around other stars, like the disks around Fomalhaut, Vega, and Epsilon Eridani, are often described as more massive versions of the Kuiper Belt. But for a long time, it's been hard to test this notion, because grain-grain collisions dominate the grain lifetimes and we lacked the tools to model the effect of collisions on the appearance of the disks. I'll describe a new breakthrough that has allowed us to make 3-D models of collisions in debris disks and exozodiacal clouds for the first time, and I'll show the latest supercomputer simulations of these systems, illustrating the effects of planets and collisions in sculpting these disks. These models will be the key to interpreting debris disk images from HST, Herschel, SOFIA, JWST, and ALMA, as well as understanding the exozodiacal dust backgrounds for direct imaging of exo-Earths.

  9. New Horizons: Long-Range Kuiper Belt Targets Observed by the Hubble Space Telescope

    NASA Technical Reports Server (NTRS)

    Benecchi, S. D.; Noll, K. S.; Weaver, H. A.; Spencer, J. R.; Stern, S. A.; Buie, M. W.; Parker, A. H.

    2014-01-01

    We report on Hubble Space Telescope (HST) observations of three Kuiper Belt Objects (KBOs), discovered in our dedicated ground-based search campaign, that are candidates for long-range observations from the New Horizons spacecraft: 2011 epochY31, 2011 HZ102, and 2013 LU35. Astrometry with HST enables both current and future critical accuracy improvements for orbit precision, required for possible New Horizons observations, beyond what can be obtained from the ground. Photometric colors of all three objects are red, typical of the Cold Classical dynamical population within which they reside; they are also the faintest KBOs to have had their colors measured. None are observed to be binary with HST above separations of approx. 0.02 arcsec (approx. 700 km at 44 AU) and delta m less than or equal to 0.5.

  10. Near-Infrared Colors of the Binary Kuiper Belt Object 1998 WW31

    NASA Astrophysics Data System (ADS)

    Takato, Naruhisa; Fuse, Tetsuharu; Gaessler, Wolfgang; Goto, Miwa; Kanzawa, Tomio; Kobayashi, Naoto; Minowa, Yosuke; Oya, Shin; Pyo, Tae-Soo; Saint-Jacque, D.; Takami, Hideki; Terada, Hiroshi; Hayano, Yutaka; Iye, Masanori; Kamata, Yukiko; Tokunaga, A. T.

    2003-06-01

    We have measured near-infrared colors of the binary Kuiper Belt object (KBO) 1998 WW31 using the Subaru Telescope with adaptive optics. The satellite was detected near its perigee and apogee (0.18'' and 1.2'' apart from the primary). The primary and the satellite have similar H-K colors, while the satellite is redder than the primary in J-H. Combined with the R band magnitude previously published by Veillet et al., 2002, the color of the primary is consistent with that of optically red KBOs. The satellite's R-, J-, H-colors suggest the presence of ~1 μm absorption band due to rock-forming minerals. If the surface of the satellite is mainly composed by olivine, the satellite's albedo is higher value than the canonically assumed value of 4%.

  11. Will New Horizons See Dust Clumps in the Edgeworth-Kuiper Belt?

    NASA Astrophysics Data System (ADS)

    Vitense, Christian; Krivov, Alexander V.; Löhne, Torsten

    2014-06-01

    Debris disks are thought to be sculptured by neighboring planets. The same is true for the Edgeworth-Kuiper debris disk, yet no direct observational evidence for signatures of giant planets in the Kuiper Belt dust distribution has been found so far. Here we model the dust distribution in the outer solar system to reproduce the dust impact rates onto the dust detector on board the New Horizons spacecraft measured so far and to predict the rates during the Neptune orbit traverse. To this end, we take a realistic distribution of trans-Neptunian objects to launch a sufficient number of dust grains of different sizes and follow their orbits by including radiation pressure, Poynting-Robertson and stellar wind drag, as well as the perturbations of four giant planets. In a subsequent statistical analysis, we calculate number densities and lifetimes of the dust grains in order to simulate a collisional cascade. In contrast to the previous work, our model not only considers collisional elimination of particles but also includes production of finer debris. We find that particles captured in the 3:2 resonance with Neptune build clumps that are not removed by collisions, because the depleting effect of collisions is counteracted by production of smaller fragments. Our model successfully reproduces the dust impact rates measured by New Horizons out to ≈23 AU and predicts an increase of the impact rate of about a factor of two or three around the Neptune orbit crossing. This result is robust with respect to the variation of the vaguely known number of dust-producing scattered disk objects, collisional outcomes, and the dust properties.

  12. A PHOTOMETRIC SYSTEM FOR DETECTION OF WATER AND METHANE ICES ON KUIPER BELT OBJECTS

    SciTech Connect

    Trujillo, Chadwick A.; Sheppard, Scott S.; Schaller, Emily L. E-mail: sheppard@dtm.ciw.edu

    2011-04-01

    We present a new near-infrared photometric system for detection of water ice and methane ice in the solar system. The system consists of two medium-band filters in the K-band region of the near-infrared, which are sensitive to water ice and methane ice, plus continuum observations in the J band and Y band. The primary purpose of this system is to distinguish between three basic types of Kuiper Belt Objects (KBOs)-those rich in water ice, those rich in methane ice, and those with little absorbance. In this work, we present proof-of-concept observations of 51 KBOs using our filter system, 21 of which have never been observed in the near-infrared spectroscopically. We show that our custom photometric system is consistent with previous spectroscopic observations while reducing telescope observing time by a factor of {approx}3. We use our filters to identify Haumea collisional family members, which are thought to be collisional remnants of a much larger body and are characterized by large fractions of water ice on their surfaces. We add 2009 YE{sub 7} to the Haumea collisional family based on our water ice band observations (J - H{sub 2}O = -1.03 {+-} 0.27) which indicate a high amount of water ice absorption, our calculated proper orbital elements, and the neutral optical colors we measured, V - R = 0.38 {+-} 0.04, which are all consistent with the rest of the Haumea family. We identify several objects dynamically similar to Haumea as being distinct from the Haumea family as they do not have water ice on their surfaces. In addition, we find that only the largest KBOs have methane ice, and Haumea itself has significantly less water ice absorption than the smaller Haumea family members. We find no evidence for other families in the Kuiper Belt.

  13. Interpretation of the Near-IR Spectra of the Kuiper Belt Object

    NASA Technical Reports Server (NTRS)

    Eluszkiewicz, Janusz; Cady-Pereira, Karen; Brown, Michael E.; Stansberry, John A.

    2007-01-01

    Visible and near-IR observations of the Kuiper Belt Object (136472) 2005 FY(9) have indicated the presence of unusually long (1 cm or more) optical path lengths in a layer of methane ice. Using microphysical and radiative transfer modeling, we show that even at the frigid temperatures in the outer reaches of the solar system, a slab of low porosity methane ice can indeed form by pressureless sintering of micron-sized grains, and it can qualitatively reproduce the salient features of the measured spectra. A good semiquantitative match with the near-IR spectra can be obtained with a realistic slab model, provided the spectra are scaled to a visible albedo of 0.6, at the low end of the values currently estimated from Spitzer thermal measurements. Consistent with previous modeling studies, matching spectra scaled to higher albedos requires the incorporation of strong backscattering effects. The albedo may become better constrained through an iterative application of the slab model to the analysis of the thermal measurements from Spitzer and the visible/near-IR reflectance spectra. The slab interpretation offers two falsifiable predictions (1) Absence of an opposition surge, which is commonly attributed to the fluffiness of the optical surface. This prediction is best testable with a spacecraft, as Earth-based observations at true opposition will not be possible until early next century. (2) Unlikelihood of the simultaneous occurrence of very long spectroscopic path lengths in both methane and nitrogen ice on the surface of any Kuiper Belt Object, as the more volatile nitrogen would hinder densification in methane ice.

  14. Will new horizons see dust clumps in the Edgeworth-Kuiper Belt?

    SciTech Connect

    Vitense, Christian; Krivov, Alexander V.; Löhne, Torsten

    2014-06-01

    Debris disks are thought to be sculptured by neighboring planets. The same is true for the Edgeworth-Kuiper debris disk, yet no direct observational evidence for signatures of giant planets in the Kuiper Belt dust distribution has been found so far. Here we model the dust distribution in the outer solar system to reproduce the dust impact rates onto the dust detector on board the New Horizons spacecraft measured so far and to predict the rates during the Neptune orbit traverse. To this end, we take a realistic distribution of trans-Neptunian objects to launch a sufficient number of dust grains of different sizes and follow their orbits by including radiation pressure, Poynting-Robertson and stellar wind drag, as well as the perturbations of four giant planets. In a subsequent statistical analysis, we calculate number densities and lifetimes of the dust grains in order to simulate a collisional cascade. In contrast to the previous work, our model not only considers collisional elimination of particles but also includes production of finer debris. We find that particles captured in the 3:2 resonance with Neptune build clumps that are not removed by collisions, because the depleting effect of collisions is counteracted by production of smaller fragments. Our model successfully reproduces the dust impact rates measured by New Horizons out to ≈23 AU and predicts an increase of the impact rate of about a factor of two or three around the Neptune orbit crossing. This result is robust with respect to the variation of the vaguely known number of dust-producing scattered disk objects, collisional outcomes, and the dust properties.

  15. NEPTUNE'S WILD DAYS: CONSTRAINTS FROM THE ECCENTRICITY DISTRIBUTION OF THE CLASSICAL KUIPER BELT

    SciTech Connect

    Dawson, Rebekah I.; Murray-Clay, Ruth

    2012-05-01

    Neptune's dynamical history shaped the current orbits of Kuiper Belt objects (KBOs), leaving clues to the planet's orbital evolution. In the 'classical' region, a population of dynamically 'hot' high-inclination KBOs overlies a flat 'cold' population with distinct physical properties. Simulations of qualitatively different histories for Neptune, including smooth migration on a circular orbit or scattering by other planets to a high eccentricity, have not simultaneously produced both populations. We explore a general Kuiper Belt assembly model that forms hot classical KBOs interior to Neptune and delivers them to the classical region, where the cold population forms in situ. First, we present evidence that the cold population is confined to eccentricities well below the limit dictated by long-term survival. Therefore, Neptune must deliver hot KBOs into the long-term survival region without excessively exciting the eccentricities of the cold population. Imposing this constraint, we explore the parameter space of Neptune's eccentricity and eccentricity damping, migration, and apsidal precession. We rule out much of parameter space, except where Neptune is scattered to a moderately eccentric orbit (e > 0.15) and subsequently migrates a distance {Delta}a{sub N} = 1-6 AU. Neptune's moderate eccentricity must either damp quickly or be accompanied by fast apsidal precession. We find that Neptune's high eccentricity alone does not generate a chaotic sea in the classical region. Chaos can result from Neptune's interactions with Uranus, exciting the cold KBOs and placing additional constraints. Finally, we discuss how to interpret our constraints in the context of the full, complex dynamical history of the solar system.

  16. Structure and Evolution of Kuiper Belt Objects: The Case for Compositional Classes

    NASA Astrophysics Data System (ADS)

    McKinnon, William B.; Prialnik, D.; Stern, S. A.

    2007-10-01

    Kuiper belt objects (KBOs) accreted from a mélange of ices, carbonaceous matter, and rock of mixed interstellar and solar nebular provenance. The transneptunian region, where this accretion took place, was likely more radially compact than today. This and the influence of gas drag during the solar nebula epoch argue for more rapid KBO accretion than usually considered. Early evolution of KBOs was largely the result of radiogenic heating, with both short-term and long-term contributions being potentially important. Depending on rock content and porous conductivity, KBO interiors may have reached relatively high temperatures. Models suggest that KBOs likely lost very volatile ices during early evolution, whereas less volatile ices should be retained in cold, less altered subsurface layers; initially amorphous ice may have crystallized in the interior as well, releasing trapped volatiles. Generally, KBOs should be stratified in terms of composition and porosity, albeit subject to impact disruption and collisional stripping. KBOs are thus unlikely to be "the most pristine objects in the Solar System.” Large (dwarf planet) KBOs may be fully differentiated. KBO surface color and compositional classes are usually discussed in terms of "nature vs. nurture,” i.e., a generic primordial composition vs. surface processing, but the true nature of KBOs also depends on how they have evolved. The broad range of albedos now found in the Kuiper belt, deep water-ice absorptions on some objects, evidence for differentiation of Pluto and 2003 EL61, and a range of densities incompatible with a single, primordial composition and variable porosity strongly imply significant, intrinsic compositional differences among KBOs. The interplay of formation zone (accretion rate), body size, and dynamical (collisional) history may yield KBO compositional classes (and their spectral correlates) that recall the different classes of asteroids in the inner Solar System, but whose members are

  17. Application of the Shuttle Laser Altimeter in an Accuracy Assessment of Global 1-Kilometer Digital Elevation Data

    NASA Technical Reports Server (NTRS)

    Harding, David J.; Carabajal, Claudia C.; Luthcke, Scott B.; Gesch, Dean B.

    1998-01-01

    Shuttle Laser Altimeter (SLA) data have been used to evaluate the accuracy of GTOPO30, the first comprehensive, 1 km resolution, global topographic data set. GTOPO30 was developed by the USGS Eros Data Center (EDC), in part, to address NASA's needs for a global topographic model in support of remote sensing instruments aboard the Earth Observing System AM-1 spacecraft. SLA flew as a part of the STS-72 mission in January, 1996 observing the latitude band from +/- 28.5 deg, and on STS-85 in August, 1997 extending the observations to +/- 57 deg. Combining the SLA ranging data with shuttle position and pointing knowledge yields surface elevation data of very high vertical accuracy in an Earth-centered, absolute reference frame (2.8 m rms difference for SLA-01 with respect to ocean reference surface). Use of the well-determined mean sea surface reference for calibration allows propagation of high accuracy altimetry onto the continents. 436,635 SLA-01 land elevations were compared to the GTOPO30 grid after conversion to a mean sea level vertical datum using the Earth Geoid Model 96, jointly developed by Goddard and NIMA. The comparison reveals systematic elevation biases in southern Asia, Africa, Australia, and south America on the order 10's to 100 meters in the GTOPO30 compilation on spatial scales of 100's to 1000's of kilometers. These biases are likely due to vertical datum errors in the topographic source materials used to compile GTOPO30, which primarily consist of Defense Mapping Agency (DMA) digital elevation and topographic map products. These biases imply that elevation corrections applied to land gravity measurements using these DMA source materials will be biased, leading to errors in geoid models incorporating these land gravity data.

  18. Crustal Layer of Seismic Velocity 6.9 to 7.6 Kilometers per Second under the Deep Oceans.

    PubMed

    Maynard, G L

    1970-04-01

    Refraction measurements made in the deep ocean between the Marshall and Hawaiian islands reveal a layer of seismic velocity 7.3 kilometers per second between the 6.8 kilometer per second oceanic crustal layer and the mantle. This layer, normally masked as a second arrival, is revealed by continuous air gun refraction data. The layer may be widespread in the deep oceans. PMID:17838983

  19. 20 CFR 663.100 - What is the role of the adult and dislocated worker programs in the One-Stop delivery system?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 20 CFR part 662. Consistent with those provisions: (1) Core services for adults and dislocated... 20 Employees' Benefits 3 2011-04-01 2011-04-01 false What is the role of the adult and dislocated... AND TRAINING ADMINISTRATION, DEPARTMENT OF LABOR ADULT AND DISLOCATED WORKER ACTIVITIES UNDER TITLE...

  20. 20 CFR 663.100 - What is the role of the adult and dislocated worker programs in the One-Stop delivery system?

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... partners described in 20 CFR part 662. Consistent with those provisions: (1) Core services for adults and... 20 Employees' Benefits 4 2013-04-01 2013-04-01 false What is the role of the adult and dislocated... AND TRAINING ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) ADULT AND DISLOCATED WORKER...

  1. Kilometer-scale topographic roughness of Mercury: Correlation with geologic features and units

    NASA Astrophysics Data System (ADS)

    Kreslavsky, Mikhail A.; Head, James W.; Neumann, Gregory A.; Zuber, Maria T.; Smith, David E.

    2014-12-01

    We present maps of the topographic roughness of the northern circumpolar area of 30 Mercury at kilometer scales. The maps are derived from range profiles obtained by the 31 Mercury Laser Altimeter (MLA) instrument onboard the MErcury Surface, Space 32 ENvironment, Geochemistry, and Ranging (MESSENGER) mission. As measures of 33 roughness, we used the interquartile range of profile curvature at three baselines: 0.7 km, 34 2.8 km, and 11 km. The maps provide a synoptic overview of variations of typical 35 topographic textures. They show a dichotomy between the smooth northern plains and 36 rougher, more heavily cratered terrains. Analysis of the scale dependence of roughness 37 indicates that the regolith on Mercury is thicker than on the Moon by approximately a 38 factor of three. Roughness contrasts within northern volcanic plains of Mercury indicate a 39 younger unit inside Goethe basin and inside another unnamed stealth basin. These new 40 data permit interplanetary comparisons of topographic roughness.

  2. Jupiter's decameter and kilometer emissions: satellite effects and long term periodicities

    SciTech Connect

    St. Cyr, O.C.

    1985-01-01

    Results of observational studies of Jupiter's decameter (DAM) and kilometer (KOM) radio emissions are presented. The initial goal was to investigate the role of Jupiter's major satellites in modulating these sporadic emissions. Concepts of electromagnetic induction in planet-sized bodies are reviewed and the Jovian magnetosphere environment and the physical characteristics of the Galilean satellites and Amalthea are described. Since the phase of Io is known to modulate the DAM emissions, the author addresses the problem of orbital resonance among the Galilean satellites. When IO's influence in the emissions is eliminated from more than two decades of ground-based observation, no significant enhancements or deficiencies in the detection probability were found for the phases of Europa, Ganymede, or Callisto. A secondary goal was to search for long term periodicities and other effects in the ground-based DAM data. As expected, a strong tendency toward an increase or decrease, respectively, in D/sub E/ was found.

  3. Preliminary Design, Feasibility and Cost Evaluation of 1- to 15-Kilometer Height Steel Towers

    NASA Technical Reports Server (NTRS)

    Shanker, Ajay

    2003-01-01

    Design and construction of tall towers is an on-going research program of NASA. The agency has already done preliminary review in this area and has determined that multi-kilometer height towers are technically and economically feasible. The proposed towers will provide high altitude launch platforms reaching above eighty percent of Earth's atmosphere and provide tremendous gains in the potential energy as well as substantial reduction in aerodynamic drag. NASA has also determined that a 15-KM tower will have many useful applications in: (i)Meteorology,(ii)Oceanography, (iii)Astronomy, (iv)High Altitude Launch, (v)Physics Drop Tower, (vi) Biosphere Research, (vii) Nanotechnology, (viii) Energy/Power, (ix)Broadband Wireless Technology, (x)Space Transportation and (xi)Space Tourism.

  4. Ultradeep (>300 kilometers) ultramafic xenoliths: petrological evidence from the transition zone.

    PubMed

    Sautter, V; Haggerty, S E; Field, S

    1991-05-10

    The seismologically delineated transition zone, at depths between 400 and 670 kilometers, is a fundamental discontinuity in the earth that separates the upper mantle from the lower mantle. Xenoliths from within or close to the transition zone are dominated by pyropic garnet and associated pyroxene or mineralogically heterogeneous garnet lherzolite. These xenoliths show evidence for the high-pressure (90 to 120 kilobars) transformation of pyroxene to a solid solution of pyroxene in garnet (majorite) and silicon in octahedral coordination; low-pressure (less than 80 kilobars) exsolution of clinopyroxene or orthopyroxene from the original majorite is preserved. Although mineral modes and rock proportions below the transition zone and the relative amount of eclogite present cannot be accurately assessed from the xenoliths, it is likely that both majorite and beta-spinel help produce the observed seismic gradient of the transition zone. PMID:17744263

  5. Evaluating the effect of internal aperture variability on transport in kilometer scale discrete fracture networks

    NASA Astrophysics Data System (ADS)

    Makedonska, Nataliia; Hyman, Jeffrey D.; Karra, Satish; Painter, Scott L.; Gable, Carl W.; Viswanathan, Hari S.

    2016-08-01

    The apertures of natural fractures in fractured rock are highly heterogeneous. However, in-fracture aperture variability is often neglected in flow and transport modeling and individual fractures are assumed to have uniform aperture distribution. The relative importance of in-fracture variability in flow and transport modeling within kilometer-scale field-scale fracture networks has been under a matter of debate for a long time because the flow in each single fracture is controlled not only by in-fracture variability but also by boundary conditions. Computational limitations have previously prohibited researchers from investigating the relative importance of in-fracture variability in flow and transport modeling within large-scale fracture networks. We address this question by incorporating internal heterogeneity of individual fractures into flow simulations within kilometer scale three-dimensional fracture networks, where fracture intensity, P32 (ratio between total fracture area and domain volume) is between 0.027 and 0.031 [1/m]. A recently developed discrete fracture network (DFN) simulation capability, dfnWorks, is used to generate DFNs that include in-fracture aperture variability represented by a stationary log-normal stochastic field with various correlation lengths and variances. The Lagrangian transport parameters, non-reacting travel time and cumulative retention, are calculated along particles streamlines. It is observed that due to local flow channeling early particle travel times are more sensitive to in-fracture variability than the tails of travel time distributions, where no significant effect of the in-fracture transmissivity variations and spatial correlation length is observed.

  6. Evaluating the effect of internal aperture variability on transport in kilometer scale discrete fracture networks

    DOE PAGESBeta

    Makedonska, Nataliia; Hyman, Jeffrey D.; Karra, Satish; Painter, Scott L.; Gable, Carl W.; Viswanathan, Hari S.

    2016-06-17

    The apertures of natural fractures in fractured rock are highly heterogeneous. However, in-fracture aperture variability is often neglected in flow and transport modeling and individual fractures are assumed to have uniform aperture distribution. The relative importance of in-fracture variability in flow and transport modeling within kilometer18 scale field–scale fracture networks has been under a matter of debate for a long time because the flow in each single fracture is controlled not only by in-fracture variability but also by boundary conditions. Computational limitations have previously prohibited researchers from investigating the relative importance of in-fracture variability in flow and transport modeling withinmore » large-scale fracture networks. We address this question by incorporating internal heterogeneity of individual fractures into 23 flow simulations within kilometer scale three-dimensional fracture networks, where fracture intensity, P32 (ratio between total fracture area and domain volume) is between 0.027 and 0.031 [1/m]. A recently developed discrete fracture network (DFN) simulation capability, dfnWorks, is used to generate DFNs that include in-fracture aperture variability represented by a stationary log-normal stochastic field with various correlation lengths and variances. The Lagrangian transport parameters, non-reacting travel time and cumulative retention, are calculated along particles streamlines. It is observed that due to local flow channeling early particle travel times are more sensitive to in-fracture variability than the tails of travel time distributions, where no significant effect of the in-fracture transmissivity variations and spatial correlation length is observed.« less

  7. 20 CFR 669.100 - What is the purpose of the National Farmworker Jobs Program (NFJP) and the other services and...

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... Farmworker Jobs Program (NFJP) and the other services and activities established under WIA section 167? 669... NATIONAL FARMWORKER JOBS PROGRAM UNDER TITLE I OF THE WORKFORCE INVESTMENT ACT Purpose and Definitions § 669.100 What is the purpose of the National Farmworker Jobs Program (NFJP) and the other services...

  8. Bioinspired design and macroscopic assembly of poly(vinyl alcohol)-coated graphene into kilometers-long fibers

    NASA Astrophysics Data System (ADS)

    Kou, Liang; Gao, Chao

    2013-05-01

    Nacre is characterized by its excellent mechanical performance due to the well-recognized ``brick and mortar'' structure. Many efforts have been applied to make nacre-mimicking materials, but it is still a big challenge to realize their continuous production. Here, we prepared sandwich-like building blocks of poly(vinyl alcohol) (PVA)-coated graphene, and achieved high-nanofiller-content kilometers-long fibers by continuous wet-spinning assembly technology. The fibers have a strict ``brick and mortar'' layered structure, with graphene sheet as rigid brick and PVA as soft mortar. The mortar thickness can be precisely tuned from 2.01 to 3.31 nm by the weight feed ratio of PVA to graphene, as demonstrated by both atomic force microscopy and X-ray diffraction measurements. The mechanical strength of the nacre-mimicking fibers increases with increasing the content of PVA, and it rises gradually from 81 MPa for the fiber with 53.1 wt% PVA to 161 MPa for the fiber with 65.8 wt% PVA. The mechanical performance of our fibers was independent of the molecular weight (MW) of PVA in the wide range of 2-100 kDa, indicating that low MW polymers can also be used to make strong nanocomposites. The tensile stress of fibers immersed in PVA 5 wt% solution reached ca. 200 MPa, surpassing the values of nacre and most of other nacre-mimicking materials. The nacre-mimicking fibers are highly electrically conductive (~350 S m-1) after immersing in hydroiodic acid, enabling them to connect a circuit to illuminate an LED lamp.Nacre is characterized by its excellent mechanical performance due to the well-recognized ``brick and mortar'' structure. Many efforts have been applied to make nacre-mimicking materials, but it is still a big challenge to realize their continuous production. Here, we prepared sandwich-like building blocks of poly(vinyl alcohol) (PVA)-coated graphene, and achieved high-nanofiller-content kilometers-long fibers by continuous wet-spinning assembly technology. The fibers

  9. Structure of the Edgeworth-Kuiper Belt (EKB) Dust Disk and Implications for Extrasolar Planet(s) epsilon Eridani

    NASA Technical Reports Server (NTRS)

    Liou, J. -C.; Zook, H. A.; Greaves, J. S.; Holland, W. S.; Boehnhardt, H.; Hahn, J. M.

    2000-01-01

    Numerical simulations of the orbital evolution of dust particles from Edgeworth-Kuiper Belt (EKB) objects show that the three giant planets, Neptune, Jupiter, and Saturn impose distinct and dramatic signatures on the overall distribution of EKB dust particles. The features are very similar to those observed in the dust disk around the nearby star Eridani. Numerical simulations of dust particles in the epsilon Eridani system show that planetary perturbations may be responsible for the observed features

  10. Missions to the Outer Solar System and Beyond - Concept Study for a Kuiper Belt Sample-Return

    NASA Astrophysics Data System (ADS)

    Ganapathy, Rohan M.

    The exploration of Kuiper belt objects (KBOs) might deliver crucial data for answering questions about the evolution of the solar system and the origin of life. Whereas the current New Horizons mission performs a flyby at KBOs, an in-depth exploration of the Kuiper belt requires an orbiter, lander or even a sample return. In this paper, we present a range of potential mission architectures for a Kuiper belt sample return mission. We use the Systems Modeling Language (SysML) for the necessary modeling and the systems engineering tool MagicDraw. A process similar to the NASA Rapid Mission Architecture approach was used. We start with a rationale a KBO sample return, dene science objectives, high-level requirements and select a strawman payload. From a key trade-matrix, mission architecture options are generated. Finally, necessary technologies and prerequisites for the mission are identied. We conclude that one of the dwarf planets Pluto, Haumea, Orcus or Quaoar and their moons should be considered as a target for the mission. The samples should be collected from the dwarf planet of choice or from its moon(s), which omits the rather high velocity requirements for a landing and departure from the dwarf planet itself. Attractive mission architectures include radioisotopic electric propulsion-based missions, missions with a combination of a solar electric propulsion stage and radioisotopic electric propulsion, or missions using nuclear electric propulsion.

  11. A CHANGE IN THE LIGHT CURVE OF KUIPER BELT CONTACT BINARY (139775) 2001 QG{sub 298}

    SciTech Connect

    Lacerda, Pedro

    2011-09-15

    New observations show that the light curve of Kuiper Belt contact binary (139775) 2001 QG{sub 298} has changed substantially since the first observations in 2003. The 2010 light curve has a peak-to-peak photometric range of {Delta}m{sub 2010} = 0.7 {+-} 0.1 mag, significantly lower than in 2003, {Delta}m{sub 2003} = 1.14 {+-} 0.04 mag. This change is most simply interpreted if 2001 QG{sub 298} has an obliquity near 90{sup 0}. The observed decrease in {Delta}m is caused by a change in viewing geometry, from equator-on in 2003 to nearly 16{sup 0} (the orbital angular distance covered by the object between the observations) off the equator in 2010. The 2003 and 2010 light curves have the same rotation period and appear in phase when shifted by an integer number of full rotations, also consistent with high obliquity. Based on the new 2010 light curve data, we find that 2001 QG{sub 298} has an obliquity of {epsilon} = 90{sup 0} {+-} 30{sup 0}. Current estimates of the intrinsic fraction of contact binaries in the Kuiper Belt are debiased assuming that these objects have randomly oriented spins. If, as 2001 QG2{sub 98}, Kuiper Belt Object contact binaries tend to have large obliquities, a larger correction is required. As a result, the abundance of contact binaries may be larger than previously believed.

  12. RETENTION OF A PRIMORDIAL COLD CLASSICAL KUIPER BELT IN AN INSTABILITY-DRIVEN MODEL OF SOLAR SYSTEM FORMATION

    SciTech Connect

    Batygin, Konstantin; Brown, Michael E.; Fraser, Wesley C.

    2011-09-01

    The cold classical population of the Kuiper Belt exhibits a wide variety of unique physical characteristics, which collectively suggest that its dynamical coherence has been maintained throughout the solar system's lifetime. Simultaneously, the retention of the cold population's relatively unexcited orbital state has remained a mystery, especially in the context of a solar system formation model, that is driven by a transient period of instability, where Neptune is temporarily eccentric. Here, we show that the cold belt can survive the instability, and its dynamical structure can be reproduced. We develop a simple analytical model for secular excitation of cold Kuiper Belt objects and show that comparatively fast apsidal precession and nodal recession of Neptune, during the eccentric phase, are essential for preservation of an unexcited state in the cold classical region. Subsequently, we confirm our results with self-consistent N-body simulations. We further show that contamination of the hot classical and scattered populations by objects of similar nature to that of cold classicals has been instrumental in shaping the vast physical diversity inherent to the Kuiper Belt.

  13. Tomography of the Galactic free electron density with the Square Kilometer Array

    NASA Astrophysics Data System (ADS)

    Greiner, M.; Schnitzeler, D. H. F. M.; Enßlin, T. A.

    2016-05-01

    We present a new algorithm for reconstructing the Galactic free electron density from pulsar dispersion measures. The algorithm performs a nonparametric tomography for a density field with an arbitrary amount of degrees of freedom. It is based on approximating the Galactic free electron density as the product of a profile function with a statistically isotropic and homogeneous log-normal field. Under this approximation the algorithm generates a map of the free electron density as well as an uncertainty estimate without the need of information about the power spectrum. The uncertainties of the pulsar distances are treated consistently by an iterative procedure. We tested the algorithm using the NE2001 model with modified fluctuations as a Galaxy model, pulsar populations generated from the Lorimer population model, and mock observations emulating the upcoming Square Kilometer Array (SKA). We show the quality of the reconstruction for mock data sets containing between 1000 and 10 000 pulsars with distance uncertainties of up to 25%. Our results show that with the SKA nonparametric tomography of the Galactic free electron density becomes feasible, but the quality of the reconstruction is very sensitive to the distance uncertainties.

  14. Kinetic simulations of kilometer-scale minimagnetosphere formation on the Moon

    NASA Astrophysics Data System (ADS)

    Zimmerman, M. I.; Farrell, W. M.; Poppe, A. R.

    2015-11-01

    Kinetic simulations are used to examine the solar wind's interaction with a 3 km wide region of strong crustal dipole magnetization on the Moon. In contrast with recent hybrid and implicit particle-in-cell simulations of magnetic anomalies that have aimed to resolve electric fields over several tens of kilometers, kinetic simulations reveal a much smaller scale regime in which magnetically driven ion-electron separation can generate a kV potential difference over a height of less than 200 m. The resulting electric field structure varies considerably between dawn and noon (when the solar wind flows, respectively, horizontally across the surface and vertically down from above) and is strong enough to reflect some ions back into space, consistent with spacecraft observations. Ion velocity and energy distributions are extracted near the surface and are used to derive maps of ion flux and impact energy, and the effects on sputtering and defect formation within the regolith are discussed. However, considerable uncertainty remains in how the surface ion flux evolves throughout a lunar day and how the plasma-surface-magnetic field interaction changes with respect to different magnetic topologies.

  15. Measurements of Magneto-Rayleigh-Taylor Instability Growth during the Implosion of Initially Solid Al Tubes Driven by the 20-MA, 100-ns Z Facility

    SciTech Connect

    Sinars, D. B.; Slutz, S. A.; Herrmann, M. C.; McBride, R. D.; Cuneo, M. E.; Peterson, K. J.; Vesey, R. A.; Nakhleh, C.; Tomlinson, K.; Edens, A. D.; Lopez, M. R.; Smith, I. C.; Shores, J.; Bigman, V.; Bennett, G. R.; Atherton, B. W.; Savage, M.; Stygar, W. A.; Leifeste, G. T.; Porter, J. L.

    2010-10-29

    The first controlled experiments measuring the growth of the magneto-Rayleigh-Taylor instability in fast ({approx}100 ns) Z-pinch plasmas are reported. Sinusoidal perturbations on the surface of an initially solid Al tube (liner) with wavelengths of 25-400 {mu}m were used to seed the instability. Radiographs with 15 {mu}m resolution captured the evolution of the outer liner surface. Comparisons with numerical radiation magnetohydrodynamic simulations show remarkably good agreement down to 50 {mu}m wavelengths.

  16. THE CANADA-FRANCE ECLIPTIC PLANE SURVEY-L3 DATA RELEASE: THE ORBITAL STRUCTURE OF THE KUIPER BELT

    SciTech Connect

    Kavelaars, J. J.; Jones, R. L.; Murray, I.; Gladman, B. J.; Petit, J.-M.; Van Laerhoven, C.; Parker, Joel Wm.; Bieryla, A.; Nicholson, P.; Margot, J. L.; Rousselot, P.; Mousis, O.; Scholl, H.; Marsden, B.; Benavidez, P.; Campo Bagatin, A.; Doressoundiram, A.; Veillet, C.

    2009-06-15

    We report the orbital distribution of the trans-Neptunian comets discovered during the first discovery year of the Canada-France Ecliptic Plane Survey (CFEPS). CFEPS is a Kuiper Belt object survey based on observations acquired by the Very Wide component of the Canada-France-Hawaii Telescope Legacy Survey (LS-VW). The first year's detections consist of 73 Kuiper Belt objects, 55 of which have now been tracked for three years or more, providing precise orbits. Although this sample size is small compared to the world-wide inventory, because we have an absolutely calibrated and extremely well-characterized survey (with known pointing history) we are able to de-bias our observed population and make unbiased statements about the intrinsic orbital distribution of the Kuiper Belt. By applying the (publically available) CFEPS Survey Simulator to models of the true orbital distribution and comparing the resulting simulated detections to the actual detections made by the survey, we are able to rule out several hypothesized Kuiper Belt object orbit distributions. We find that the main classical belt's so-called 'cold' component is confined in semimajor axis (a) and eccentricity (e) compared to the more extended 'hot' component; the cold component is confined to lower e and does not stretch all the way out to the 2:1 resonance but rather depletes quickly beyond a = 45 AU. For the cold main classical belt population we find a robust population estimate of N(H{sub g} < 10) = 50 {+-} 5 x 10{sup 3} and find that the hot component of the main classical belt represents {approx}60% of the total population. The inner classical belt (sunward of the 3:2 mean-motion resonance) has a population of roughly 2000 trans-Neptunian objects with absolute magnitudes H{sub g} < 10, and may not share the inclination distribution of the main classical belt. We also find that the plutino population lacks a cold low-inclination component, and so, the population is somewhat larger than recent estimates

  17. Migration of Matter from the Edgeworth-Kuiper and Main Asteroid Belts to the Earth

    NASA Technical Reports Server (NTRS)

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

    2002-01-01

    The main asteroid belt (MAB), the Edgeworth-Kuiper belt (EKB), and comets belong to the main sources of dust in the Solar System. Most of Jupiter-family comets came from the EKB. Comets can be distracted due to close encounters with planets and the Sun, collisions with small bodies, a nd internal forces. We support the Eneev's idea that the largest objects in the ELB and MAB could be formed directly by the compression of rarefied dust condensations of the protoplanetary cloud but not by the accretion of small (for example, 1-km) planetesimals. The total mass of planetesimals that entered the EKB from the feeding zone of the giant planets during their accumulation could exceed tens of Earth's masses. These planetesimals increased eccentricities of 'local' trans-Neptunian objects (TNOs) and swept most of these TNOs. A small portion of such planetesimals could left beyond Neptune's orbit in highly eccentric orbits. The results of previous investigations of migration and collisional evolution of minor bodies were summarized. Mainly our recent results are presented.

  18. Orbital clustering of distant Kuiper belt objects by hypothetical Planet 9. Secular or resonant?

    NASA Astrophysics Data System (ADS)

    Beust, H.

    2016-05-01

    Context. Statistical analysis of the orbits of distant Kuiper belt objects (KBOs) has led to the suggestion that an additional planet should reside in the solar system. According to recent models, the secular action of this body should cause orbital alignment of the KBOs. Aims: It was recently claimed that the KBOs affected by these dynamics are presumably trapped in mean-motion resonances with the suspected planet. I reinvestigate here the secular model underlying this idea. Methods: The original analysis was carried out by expanding and truncating the secular Hamiltonian. I show that this is inappropriate, as the series expansion is not convergent. I present a study based on numerical computation of the Hamiltonian with no expansion. Results: I show in phase-space diagrams the existence of apsidally anti-aligned, high eccentricity libration islands that were not present in the original modelling, but match numerical simulations. These island were claimed to correspond to bodies trapped in mean-motion resonances with the hypothetical planet and match the characteristics of the distant KBOs observed. Conclusions: My main result is that regular secular dynamics can account for the anti-aligned particles itself as well as mean-motion resonances. I also perform a semi-analytical study of resonant motion and show that some resonance are actually capable of producing the same libration islands. I then discuss the relative importance of both mechanisms.

  19. A hardware/software simulation for the video tracking system of the Kuiper Airborne Observatory telescope

    NASA Technical Reports Server (NTRS)

    Boozer, G. A.; Mckibbin, D. D.; Haas, M. R.; Erickson, E. F.

    1984-01-01

    This simulator was created so that C-141 Kuiper Airborne Observatory investigators could test their Airborne Data Acquisition and Management System software on a system which is generally more accessible than the ADAMS on the plane. An investigator can currently test most of his data acquisition program using the data computer simulator in the Cave. (The Cave refers to the ground-based computer facilities for the KAO and the associated support personnel.) The main Cave computer is interfaced to the data computer simulator in order to simulate the data-Exec computer communications. However until now, there has been no way to test the data computer interface to the tracker. The simulator described here simulates both the KAO Exec and tracker computers with software which runs on the same Hewlett-Packard (HP) computer as the investigator's data acquisition program. A simulator control box is hardwired to the computer to provide monitoring of tracker functions, to provide an operator panel similar to the real tracker, and to simulate the 180 deg phase shifting of the chopper squre-wave reference with beam switching. If run in the Cave, one can use their Exec simulator and this tracker simulator.

  20. Kuiper Airborne Observatory's Telescope Stabilization System: Disturbance Sensitivity Reduction Via Velocity Loop Feedback

    NASA Technical Reports Server (NTRS)

    Lawrence, David P.; Tsui, K. C.; Tucker, John; Mancini, Ronald E. (Technical Monitor)

    1995-01-01

    In July of 1994 the Kuiper Airborne Observatory's (KAO) Telescope Stabilization System (TSS) was upgraded to meet performance goals necessary to view the Shoemaker-Levy 9 comet collision with Jupiter. The KAO is a modified C-141 Aircraft supporting a 36 inch Infrared telescope used to gather and analyze astronomical data. Before the upgrade, the TSS exhibited approximately a 10 arc-second resolution pointing accuracy. The majority of the inaccuracy was attributable to aircraft vibration and wind buffeting entering through the aircraft's telescope door opening; in other words, the TSS was overly sensitive to external disturbances. Because of power limitations and noise requirements, improving the pointing accuracy of the telescope required more sophistication than simply raising the bandwidth as some classical control strategies might suggest. Instead, relationships were developed between the disturbance sensitivity and closed loop transfer functions. These relationships suggested that employing velocity feedback along with an increase in current loop gain would dramatically improve the pointing resolution of the TSS by decreasing the control system's sensitivity to external disturbances. With the implementation of some classical control techniques and the above philosophy, the KAO's TSS's resolution was improved to approximately 2-3 arc-seconds.

  1. Targeted Recovery of 2014A Candidate Kuiper Belt Objects for New Horizons Flyby

    NASA Astrophysics Data System (ADS)

    Parker, Alex; Spencer, John; Buie, Marc; Stern, S. Alan; Tholen, David; Trilling, David; Fuentes, Cesar

    2014-08-01

    We propose to recover up to three Kuiper Belt Objects (KBOs) discovered as part of a survey searching for candidate KBO targets for NASA's New Horizons spacecraft to visit after the 2015 Pluto encounter. The first flyby of a small ( 50km) KBO would revolutionize out understanding of this population, and the environment they are embedded in. Our survey has been allocated substantial time in 2014A on Magellan and Subaru to search for faint encounter candidates (r 26-26.4). Discovery observations will be insufficient to identify true encounter candidates, and follow-up observations in the 2014B semester will be required to refine candidate KBOs' orbital properties sufficiently to determine if New Horizons can reach a given object with its remaining fuel. Given expected discovery astrometry, we can robustly rank candidates for follow-up, and selecting three candidates for follow-up observations will be sufficient to recover one true encounter candidate at greater than 99% confidence. Here we propose for 6 hours of TOO time for this targeted follow-up of our highest-priority 2014A discoveries using GMOS on Gemini North. These follow-up observations will increase the precision and accuracy of our orbit measurements, and will refine the sample of candidate KBOs by improving our ability to discriminate between accessible and non-accessible objects.

  2. Prerequisites for explosive cryovolcanism on dwarf planet-class Kuiper belt objects

    NASA Astrophysics Data System (ADS)

    Neveu, M.; Desch, S. J.; Shock, E. L.; Glein, C. R.

    2015-01-01

    Explosive extrusion of cold material from the interior of icy bodies, or cryovolcanism, has been observed on Enceladus and, perhaps, Europa, Triton, and Ceres. It may explain the observed evidence for a young surface on Charon (Pluto's surface is masked by frosts). Here, we evaluate prerequisites for cryovolcanism on dwarf planet-class Kuiper belt objects (KBOs). We first review the likely spatial and temporal extent of subsurface liquid, proposed mechanisms to overcome the negative buoyancy of liquid water in ice, and the volatile inventory of KBOs. We then present a new geochemical equilibrium model for volatile exsolution and its ability to drive upward crack propagation. This novel approach bridges geophysics and geochemistry, and extends geochemical modeling to the seldom-explored realm of liquid water at subzero temperatures. We show that carbon monoxide (CO) is a key volatile for gas-driven fluid ascent; whereas CO2 and sulfur gases only play a minor role. N2, CH4, and H2 exsolution may also drive explosive cryovolcanism if hydrothermal activity produces these species in large amounts (a few percent with respect to water). Another important control on crack propagation is the internal structure: a hydrated core makes explosive cryovolcanism easier, but an undifferentiated crust does not. We briefly discuss other controls on ascent such as fluid freezing on crack walls, and outline theoretical advances necessary to better understand cryovolcanic processes. Finally, we make testable predictions for the 2015 New Horizons flyby of the Pluto-Charon system.

  3. ON A POSSIBLE SIZE/COLOR RELATIONSHIP IN THE KUIPER BELT

    SciTech Connect

    Pike, R. E.; Kavelaars, J. J.

    2013-10-01

    Color measurements and albedo distributions introduce non-intuitive observational biases in size-color relationships among Kuiper Belt Objects (KBOs) that cannot be disentangled without a well characterized sample population with systematic photometry. Peixinho et al. report that the form of the KBO color distribution varies with absolute magnitude, H. However, Tegler et al. find that KBO color distributions are a property of object classification. We construct synthetic models of observed KBO colors based on two B-R color distribution scenarios: color distribution dependent on H magnitude (H-Model) and color distribution based on object classification (Class-Model). These synthetic B-R color distributions were modified to account for observational flux biases. We compare our synthetic B-R distributions to the observed ''Hot'' and ''Cold'' detected objects from the Canada-France Ecliptic Plane Survey and the Meudon Multicolor Survey. For both surveys, the Hot population color distribution rejects the H-Model, but is well described by the Class-Model. The Cold objects reject the H-Model, but the Class-Model (while not statistically rejected) also does not provide a compelling match for data. Although we formally reject models where the structure of the color distribution is a strong function of H magnitude, we also do not find that a simple dependence of color distribution on orbit classification is sufficient to describe the color distribution of classical KBOs.

  4. The size and albedo of the Kuiper-belt object (20000) Varuna.

    PubMed

    Jewitt, D; Aussel, H; Evans, A

    2001-05-24

    Observations over the last decade have revealed the existence of a large number of bodies orbiting the Sun beyond Neptune. Known as the Kuiper-belt objects (KBOs), they are believed to be formed in the outer reaches of the protoplanetary disk around the young Sun, and have been little altered since then. They are probably the source of short-period comets. The KBOs are, however, difficult objects to study because of their distance from earth, so even basic physical properties such as their sizes and albedos remain unknown. Previous size estimates came from assuming an albedo with the canonical value being 0.04. Here we report simultaneous measurements of the thermal emission and reflected optical light of the bright KBO (20000) Varuna, which allow us to determine independently both the size and the albedo. Varuna has an equivalent circular diameter of D = 900+129-145 km and a red geometric albedo of pR = 0.070+0.030-0.017. Its surface is darker than Pluto's, suggesting that it is largely devoid of fresh ice, but brighter than previously assumed for KBOs. PMID:11373669

  5. Dispersal of Disks Around Young Stars: Constraints on Kuiper Belt Formation

    NASA Technical Reports Server (NTRS)

    Hollenbach, David; DeVincenzi, Donald (Technical Monitor)

    2002-01-01

    We review the evidence pertaining to the lifetimes of planet-forming disks and discuss possible disk dispersal mechanisms: 1) viscous accretion of material onto the central source; 2) close stellar encounters; 3) stellar winds; and 4) photoevaporation by ultraviolet radiation. We focus on 3) and 4) and describe the quasi-steady state appearance and the overall evolution of disks under the influence of winds and radiation from the central star and of radiation from external OB stars. Viscous accretion likely dominates disk dispersal in the inner disk (r approx. <= 10 AU), while photoevaporation is the principal process of disk dispersal outside of r approx. >= 10 AU for low mass stars. Disk dispersal timescales are compared and discussed in relation to theoretical estimates for planet formation timescales. Photoevaporation may explain the large differences in the hydrogen content of the giant planets in the solar system. The commonly held belief that our early sun's stellar wind dispersed the solar nebula is called into question. Finally, we study the constraints that the evaporation of the outer disk has on the formation of Kuiper belts in extrasolar planetary systems.

  6. A giant impact origin for Pluto's small moons and satellite multiplicity in the Kuiper belt.

    PubMed

    Stern, S A; Weaver, H A; Steffl, A J; Mutchler, M J; Merline, W J; Buie, M W; Young, E F; Young, L A; Spencer, J R

    2006-02-23

    The two newly discovered satellites of Pluto (P1 and P2) have masses that are small compared to both Pluto and Charon-that is, between 5 x 10(-4) and 1 x 10(-5) of Pluto's mass, and between 5 x 10(-3) and 1 x 10(-4) of Charon's mass. This discovery, combined with the constraints on the absence of more distant satellites of Pluto, reveal that Pluto and its moons comprise an unusual, highly compact, quadruple system. These facts naturally raise the question of how this puzzling satellite system came to be. Here we show that P1 and P2's proximity to Pluto and Charon, the fact that P1 and P2 are on near-circular orbits in the same plane as Pluto's large satellite Charon, along with their apparent locations in or near high-order mean-motion resonances, all probably result from their being constructed from collisional ejecta that originated from the Pluto-Charon formation event. We also argue that dust-ice rings of variable optical depths form sporadically in the Pluto system, and that rich satellite systems may be found--perhaps frequently--around other large Kuiper belt objects. PMID:16495992

  7. Extremely red Kuiper-belt objects in near-circular orbits beyond 40 AU.

    PubMed

    Tegler, S C; Romanishin, W

    2000-10-26

    Kuiper-belt objects (KBOs) are an ancient reservoir of comets beyond Neptune's orbit. Some of these objects were recently found to have the reddest optical colours in the Solar System, but the number of objects for which accurate colours were available was too small for any correlation to be discerned between colour and physical or dynamical properties, which might shed light on the origin of these objects. Here we report that all nine of the KBOs in our survey on near-circular (low-eccentricity) orbits with perihelion distances larger than 40 AU have extremely red surfaces, thereby connecting an observable property with a dynamical class. Of the objects with orbital eccentricities greater than 0.1, about half are also very red, while the rest have colours similar to the Sun, meaning that reflected sunlight is not strongly modified by the objects' surface properties. In addition, of the 13 'classical' KBOs (those with semimajor axis a approximately 45 AU and eccentricity e < 0.15), the ten that are very red are in orbits with small angles of inclination to the ecliptic, whereas the three with solar colours are all in high-inclination orbits. We suggest that these three 'grey' classical KBOs may be part of a dynamical group that is separate from the 'red' classical KBOs. PMID:11069171

  8. Dynamical Heating Induced by Dwarf Planets on Cold Kuiper Belt–like Debris Disks

    NASA Astrophysics Data System (ADS)

    Muñoz-Gutiérrez, M. A.; Pichardo, B.; Reyes-Ruiz, M.; Peimbert, A.

    2015-10-01

    With the use of long-term numerical simulations, we study the evolution and orbital behavior of cometary nuclei in cold Kuiper belt–like debris disks under the gravitational influence of dwarf planets (DPs); we carry out these simulations with and without the presence of a Neptune-like giant planet. This exploratory study shows that in the absence of a giant planet, 10 DPs are enough to induce strong radial and vertical heating on the orbits of belt particles. On the other hand, the presence of a giant planet close to the debris disk, acts as a stability agent reducing the radial and vertical heating. With enough DPs, even in the presence of a Neptune-like giant planet some radial heating remains; this heating grows steadily, re-filling resonances otherwise empty of cometary nuclei. Specifically for the solar system, this secular process seems to be able to provide material that, through resonant chaotic diffusion, increase the rate of new comets spiraling into the inner planetary system, but only if more than the ∼10 known DP sized objects exist in the trans-Neptunian region.

  9. A Chemical and Dynamical Link Between Red Centaur Objects and the Cold Classical Kuiper Belt

    NASA Astrophysics Data System (ADS)

    Tegler, Stephen C.; Romanishin, William; Consolmagno, Guy

    2015-11-01

    We present new B-V, V-R, and B-R colors for 32 Centaurs objects using the 4.3-meter Discovery Channel Telescope (DCT) near Happy Jack, AZ and the 1.8-meter Vatican Advanced Technology Telescope on Mt. Graham, AZ. Combining these new colors with our previously reported colors, we now have optical broad-band colors for 58 Centaur objects.Application of the non-parametric Dip Test to our previous sample of only 26 objects showed Centaurs split into gray and red groups at the 99.5% confidence level, and application of the Wilcoxon Rank Sum Test to the same sample showed that red Centaurs have a higher median albedo than gray Centaurs at the 99% confidence level (Tegler et al., 2008, Solar System Beyond Neptune, U Arizona Press, pp. 105-114).Here we report application of the Wilcoxon Rank Sum Test to our sample of 58 Centaurs. We confirm red Centaurs have a higher median albedo than gray Centaurs at the 99.7% level. In addition, we find that red Centaurs have a lower median inclination angle than gray Centaurs at the 99.5% confidence level. Because of their red colors and lower inclination angles, we suggest red Centaurs originate in the cold classical Kuiper belt. We thank the NASA Solar System Observations Program for its support.

  10. Photometry of cometary nuclei: rotation rates, colours and a comparison with Kuiper Belt Objects

    NASA Astrophysics Data System (ADS)

    Snodgrass, C.; Lowry, S. C.; Fitzsimmons, A.

    2006-12-01

    We present time-series data on Jupiter Family Comets (JFCs) 17P/Holmes, 47P/Ashbrook-Jackson and 137P/Shoemaker-Levy 2. In addition we also present results from `snap-shot' observations of comets 43P/Wolf-Harrington, 44P/Reinmuth 2, 103P/Hartley 2 and 104P/Kowal 2 taken during the same run. The comets were at heliocentric distances of between 3 and 7 au at this time. We present measurements of size and activity levels for the snap-shot targets. The time-series data allow us to constrain rotation periods and shapes, and thus bulk densities. We also measure colour indices (V - R) and (R - I) and reliable radii for these comets. We compare all of our findings to date with similar results for other comets and Kuiper Belt Objects (KBOs). We find that the rotational properties of nuclei and KBOs are very similar, that there is evidence for a cut-off in bulk densities at ~0.6 g cm-3 in both populations, and the colours of the two populations show similar correlations. For JFCs, there is no observational evidence for the optical colours being dependent on either position in the orbit or orbital parameters. Based on observations collected at the European Southern Observatory, Chile. Proposal: ESO No. 74.C-0125. E-mail: csnodgra@eso.org

  11. Environmental Impact Specification for Direct Space Weathering of Kuiper Belt and Oort Cloud Objects

    NASA Technical Reports Server (NTRS)

    Cooper, John F.

    2010-01-01

    The Direct Space Weathering Project of NASA's Outer Planets Research Program addresses specification of the plasma and energetic particle environments for irradiation and surface chemical processing of icy bodies in the outer solar system and the local interstellar medium. Knowledge of the radiation environments is being expanded by ongoing penetration of the twin Voyager spacecraft into the heliosheath boundary region of the outer heliosphere and expected emergence within the next decade into the very local interstellar medium. The Voyager measurements are being supplemented by remote sensing from Earth orbit of energetic neutral atom emission from this boundary region by NASA's Interstellar Boundary Explorer (IBEX). Although the Voyagers long ago passed the region of the Classical Kuiper Belt, the New Horizons spacecraft will encounter Pluto in 2015 and thereafter explore one or more KBOs, meanwhile providing updated measurements of the heliospheric radiation environment in this region. Modeling of ion transport within the heliosphere allows specification of time-integrated irradiation effects while the combination of Voyager and IBEX data supports projection of the in-situ measurements into interstellar space beyond the heliosheath. Transformation of model ion flux distributions into surface sputtering and volume ionization profiles provides a multi-layer perspective for space weathering impact on the affected icy bodies and may account for some aspects of color and compositional diversity. Other important related factors may include surface erosion and gardening by meteoritic impacts and surface renewal by cryovolcanism. Chemical products of space weathering may contribute to energy resources for the latter.

  12. Evaluation of heterogeneous porosity in reservoirs on Arabian platform: microns to kilometers

    SciTech Connect

    Nurmi, R.; Charara, M.; Waterhouse, M.

    1988-02-01

    A common heterogeneity is the occurrence of patchy porosity, which may occur at any scale of examination. The occurrence of patchy porosity at a scale of kilometers is a factor controlling the areal distribution of reservoirs. Although often related to depositional facies, in some areas this distribution has not been adequately explained. The three-dimensional mapping of such large-scale porosity has been carried out by well mapping and/or seismic velocity mapping. The presence of meter-scale patchy porosity is routinely detected in Cretaceous-age reservoirs using borehole electrical imagery. Although the patterns of patchy porosity are revealed in these images, porosity variation is only shown in relative terms. It is possible, however, to use high-resolution porosity measurements to quantify these variations, which is especially important when there is a continuous network of high porosity. This type of heterogeneity sometimes erroneously causes indications of secondary porosity. Although the origin of these porosity variations is not well understood, SEM examination of some low-porosity areas indicates that they are the result of an abundance of micron-scale patchy recrystallization. Patchy distribution of anhydrite is a common form of reservoir heterogeneity in Jurassic and Tertiary reservoirs. Electrical images clearly reveal the various fabrics of anhydrite within carbonate and sandstone reservoirs. Although this type of heterogeneity has been long recognized by geologists, it is only now being included in thorough log evaluation efforts. Unless such heterogeneously distributed anhydrite is recognized and accounted for, the evaluation of these reservoir zones can be inappropriately pessimistic or falsely indicative of hydrocarbons.

  13. Stellar intensity interferometry over kilometer baselines: laboratory simulation of observations with the Cherenkov Telescope Array

    NASA Astrophysics Data System (ADS)

    Dravins, Dainis; Lagadec, Tiphaine

    2014-07-01

    A long-held astronomical vision is to realize diffraction-limited optical aperture synthesis over kilometer baselines. This will enable imaging of stellar surfaces and their environments, show their evolution over time, and reveal interactions of stellar winds and gas flows in binary star systems. An opportunity is now opening up with the large telescope arrays primarily erected for measuring Cherenkov light in air induced by gamma rays. With suitable software, such telescopes could be electronically connected and used also for intensity interferometry. With no optical connection between the telescopes, the error budget is set by the electronic time resolution of a few nanoseconds. Corresponding light-travel distances are on the order of one meter, making the method practically insensitive to atmospheric turbulence or optical imperfections, permitting both very long baselines and observing at short optical wavelengths. Theoretical modeling has shown how stellar surface images can be retrieved from such observations and here we report on experimental simulations. In an optical laboratory, artificial stars (single and double, round and elliptic) are observed by an array of telescopes. Using high-speed photon-counting solid-state detectors and real-time electronics, intensity fluctuations are cross correlated between up to a hundred baselines between pairs of telescopes, producing maps of the second-order spatial coherence across the interferometric Fourier-transform plane. These experiments serve to verify the concepts and to optimize the instrumentation and observing procedures for future observations with (in particular) CTA, the Cherenkov Telescope Array, aiming at order-of-magnitude improvements of the angular resolution in optical astronomy.

  14. Viscosity, density, and surface tension of binary mixtures of water and N-methyldiethanolamine and water and diethanolamine and tertiary mixtures of these amines with water over the temperature range 20--100[degree]C

    SciTech Connect

    Rinker, E.B.; Oelschlager, D.W.; Colussi, A.T.; Henry, K.R.; Sandall, O.C. . Dept. of Chemical and Nuclear Engineering)

    1994-04-01

    Aqueous solutions of N-methyldiethanolamine (MDEA) and diethanolamine (DEA) are widely used in the industrial treatment of acid gas streams containing H[sub 2]S and CO[sub 2]. The density and viscosity of aqueous solutions of N-methyldiethanolamine were measured over the temperature range 60--100 C. The density and viscosity of aqueous solutions of diethanolamine and diethanolamine + N-methyldiethanolamine were measured over the temperature range 20--100 C. The surface tension of aqueous solutions of the above mixtures was measured over the temperature range 20--80 C. The concentration ranges were 10--50 mass % N-methyldiethanolamine, 10--30 mass % diethanolamine, and 50 mass % total amine concentration with mass ratios of 0.0441--0.5883 (diethanolamine to N-methyldiethanolamine). The measured quantities were found to be in agreement with the literature where data were available.

  15. Snow depth estimation, structure, prediction, and hydrologic modeling at the kilometer scale in the Colorado Rocky Mountains

    NASA Astrophysics Data System (ADS)

    McCreight, James L.

    Research focuses on observing and predicting spatial distribution of snow depth at the kilometer scale. Observation of spatial snow depth distribution is considered by its estimation from random, sparse observations and important factors affecting this estimation. Predicting spatial distribution of both snow depth and melt rates begins from simple hypothesis wherein the spatial distribution of snow depth is structured by the spatial distribution of controlling variables. Predictions made by this structured view are evaluated in spatial modeling of peak-accumulation snow depth and applied to spatial distribution of a point-scale, temperature-index model of snowmelt runoff using minimal parameter complexity. High-resolution light detection and ranging (LiDAR) measurements provide a rich backdrop for understanding estimation from sparse observations and developing our structured view of snow distribution. The data are used to illuminate the effects of sample size on estimation skill, the uncertainty in estimation due to random sampling, the effect of model resolution on estimation skill, and the difference between cross-validated skill and skill based on the entire distribution. None of these topics have previously been explored in the literature. The effect of predictor quality is also investigated. LiDAR derived predictors are compared to readily available predictors downloaded from the internet. Hierarchical cluster analysis is used to decompose spatial non-stationarity of snow depth and results match qualitative understanding of the spatial distribution of physical controls. The same methodology is then used to decompose spatial non-stationarity of physical controls and infer patterns of snow depth distribution independent of observations. Even when using readily-available predictors, predicted patterns require at least 100--200 observations to be matched by standard estimation methods. Predicted patterns are then applied to formulate a parameterized spatial

  16. A BVRI Color Survey of Kilometer-Scale Themis Family Asteroids

    NASA Astrophysics Data System (ADS)

    Hsieh, Henry H.

    2009-09-01

    The Themis asteroid family in the outer asteroid belt is thought to be the result of the collisional disruption of a 400-km parent asteroid about 2.5 Gyr ago. This family has recently become of particular interest following the identification of the main-belt comets (MBCs; observationally cometary bodies that are dynamically indistinguishable from main-belt asteroids), given that two (133P/Elst-Pizarro and 176P/LINEAR) of the four currently known MBCs are family members, and a third MBC (P/2005 U1 (Read)) also exhibits striking dynamical similarities. The small sizes of all four currently known MBCs [1,2,3] as well as their present-day volatility, however, suggests that they may not actually be primordial members of the Themis family and are instead fragments of more recent disruptions, possibly of other larger Themis members [4]. As part of an ongoing effort to understand the MBCs in the context of their surroundings and also to search for observational clues pertaining to the origins of MBC-sized Themis asteroids, I have conducted optical observations, obtained using BVRI filters at the University of Hawai`i 2.2-m and Subaru 8.2-m telescopes on Mauna Kea, of 59 kilometer-scale (HV>14.4) Themis asteroids. I will present color data from this survey, and compare them with colors observed for MBC nuclei, larger Themis asteroids, and other small solar system body populations of note, and discuss the implications of these results for our understanding of the origin and nature of MBC activity and for the potential development of criteria for identifying other MBCs even in the absence of detectable cometary activity. This work was supported by a NASA Planetary Astronomy Grant (via David Jewitt) and by the United Kingdom's Science and Technology Facilities Council through fellowship grant ST/F011016/1. References: [1] 2009, AJ 137, 157; [2] 2009, ApJL 694, 111; [3] 2009, AJ 137, 4313; [4] 2009, A&A, submitted

  17. Comet-like mineralogy of olivine crystals in an extrasolar proto-Kuiper belt.

    PubMed

    de Vries, B L; Acke, B; Blommaert, J A D L; Waelkens, C; Waters, L B F M; Vandenbussche, B; Min, M; Olofsson, G; Dominik, C; Decin, L; Barlow, M J; Brandeker, A; Di Francesco, J; Glauser, A M; Greaves, J; Harvey, P M; Holland, W S; Ivison, R J; Liseau, R; Pantin, E E; Pilbratt, G L; Royer, P; Sibthorpe, B

    2012-10-01

    Some planetary systems harbour debris disks containing planetesimals such as asteroids and comets. Collisions between such bodies produce small dust particles, the spectral features of which reveal their composition and, hence, that of their parent bodies. A measurement of the composition of olivine crystals (Mg(2-2x)Fe(2x)SiO(4)) has been done for the protoplanetary disk HD 100546 (refs 3, 4) and for olivine crystals in the warm inner parts of planetary systems. The latter compares well with the iron-rich olivine in asteroids (x ≈ 0.29). In the cold outskirts of the β Pictoris system, an analogue to the young Solar System, olivine crystals were detected but their composition remained undetermined, leaving unknown how the composition of the bulk of Solar System cometary olivine grains compares with that of extrasolar comets. Here we report the detection of the 69-micrometre-wavelength band of olivine crystals in the spectrum of β Pictoris. Because the disk is optically thin, we can associate the crystals with an extrasolar proto-Kuiper belt a distance of 15-45 astronomical units from the star (one astronomical unit is the Sun-Earth distance), determine their magnesium-rich composition (x = 0.01 ± 0.001) and show that they make up 3.6 ± 1.0 per cent of the total dust mass. These values are strikingly similar to those for the dust emitted by the most primitive comets in the Solar System, even though β Pictoris is more massive and more luminous and has a different planetary system architecture. PMID:23038467

  18. OBSERVED BINARY FRACTION SETS LIMITS ON THE EXTENT OF COLLISIONAL GRINDING IN THE KUIPER BELT

    SciTech Connect

    Nesvorny, David; Vokrouhlicky, David; Bottke, William F.; Levison, Harold F.; Noll, Keith

    2011-05-15

    The size distribution in the cold classical Kuiper Belt (KB) can be approximated by two idealized power laws: one with steep slope for radii R > R* and one with shallow slope for R < R*, where R* {approx} 25-50 km. Previous works suggested that the size frequency distribution (SFD) rollover at R* can be the result of extensive collisional grinding in the KB that led to the catastrophic disruption of most bodies with R < R*. Here, we use a new code to test the effect of collisions in the KB. We find that the observed rollover could indeed be explained by collisional grinding provided that the initial mass in large bodies was much larger than the one in the present KB and was dynamically depleted. In addition to the size distribution changes, our code also tracks the effects of collisions on binary systems. We find that it is generally easier to dissolve wide binary systems, such as the ones existing in the cold KB today, than to catastrophically disrupt objects with R {approx} R*. Thus, the binary survival sets important limits on the extent of collisional grinding in the KB. We find that the extensive collisional grinding required to produce the SFD rollover at R* would imply a strong gradient of the binary fraction with R and separation, because it is generally easier to dissolve binaries with small components and/or those with wide orbits. The expected binary fraction for R {approx}< R* is {approx}<0.1. The present observational data do not show such a gradient. Instead, they suggest a large binary fraction of {approx}0.4 for R = 30-40 km. This may indicate that the rollover was not produced by disruptive collisions, but is instead a fossil remnant of the KB object formation process.

  19. SLOAN DIGITAL SKY SURVEY OBSERVATIONS OF KUIPER BELT OBJECTS: COLORS AND VARIABILITY

    SciTech Connect

    Ofek, Eran O.

    2012-04-10

    Colors of trans-Neptunian objects (TNOs) are used to study the evolutionary processes of bodies in the outskirts of the solar system and to test theories regarding their origin. Here I describe a search for serendipitous Sloan Digital Sky Survey (SDSS) observations of known TNOs and Centaurs. I present a catalog of SDSS photometry, colors, and astrometry of 388 measurements of 42 outer solar system objects. I find weak evidence, at the Almost-Equal-To 2{sigma} level (per trial), for a correlation between the g - r color and inclination of scattered disk objects and hot classical Kuiper Belt objects. I find a correlation between the g - r color and the angular momentum in the z direction of all the objects in this sample. These findings should be verified using larger samples of TNOs. Light curves as a function of phase angle are constructed for 13 objects. The steepness of the slopes of these light curves suggests that the coherent backscatter mechanism plays a major role in the reflectivity of outer solar system small objects at small phase angles. I find weak evidence for an anticorrelation, significant at the 2{sigma} confidence level (per trial), between the g-band phase-angle slope parameter and the semimajor axis, as well as the aphelion distance, of these objects (i.e., they show a more prominent 'opposition effect' at smaller distances from the Sun). However, this plausible correlation should be verified using a larger sample. I discuss the origin of this possible correlation and argue that if this correlation is real it probably indicates that 'Sedna'-like objects have a different origin than other classes of TNOs. Finally, I identify several objects with large variability amplitudes.

  20. THE ROTATION PERIOD AND LIGHT-CURVE AMPLITUDE OF KUIPER BELT DWARF PLANET 136472 MAKEMAKE (2005 FY9)

    SciTech Connect

    Heinze, A. N.; DeLahunta, Daniel E-mail: ddelahun@mail.rochester.edu

    2009-08-15

    Kuiper Belt dwarf planet 136472 Makemake, formerly known as 2005 FY9, is currently the third-largest known object in the Kuiper Belt, after the dwarf planets Pluto and Eris. It is currently second only to Pluto in apparent brightness, due to Eris' much larger heliocentric distance. Makemake shows very little photometric variability, which has prevented confident determination of its rotation period until now. Using extremely precise time-series photometry, we find that the rotation period of Makemake is 7.7710 {+-} 0.0030 hr, where the uncertainty is a 90% confidence interval. An alias period is detected at 11.41 hr, but is determined with approximately 95% confidence not to be the true period. Makemake's 7.77 hr rotation period is in the typical range for Kuiper Belt objects, consistent with Makemake's apparent lack of a substantial satellite to alter its rotation through tides. The amplitude of Makemake's photometric light curve is 0.0286 {+-} 0.0016 mag in V. This amplitude is about 10 times less than Pluto's, which is surprising given the two objects' similar sizes and spectral characteristics. Makemake's photometric variability is instead similar to that of Eris, which is so small that no confident rotation period has yet been determined. It has been suggested that dwarf planets such as Makemake and Eris, both farther from the Sun and colder than Pluto, exhibit lower photometric variability because they are covered with a uniform layer of frost. Such a frost is probably the correct explanation for Eris. However, it may be inconsistent with the spectrum of Makemake, which resembles reddish Pluto more than neutrally colored Eris. Makemake may instead be a more Pluto-like object that we observe at present with a nearly pole-on viewing geometry-a possibility that can be tested with continuing observations over the coming decades.

  1. Combining Saturnian Craters and Kuiper Belt Observations to Build an Outer Solar System Impactor Size-Frequency Distribution

    NASA Astrophysics Data System (ADS)

    Minton, D. A.; Richardson, J. E.; Thomas, P.; Kirchoff, M.; Schwamb, M. E.

    2012-05-01

    Using Cassini mission imagery of the icy satellites of Saturn, numerical simulations, and telescopic observation data we produce a model size frequency distribution for outer solar system impactors spanning tens of meters to thousands of kilometers.

  2. Combining Saturnian Craters and Kuiper Belt Observations to Build an Outer Solar System Impactor Size-Frequency Distribution

    NASA Astrophysics Data System (ADS)

    Minton, D. A.; Richardson, J. E.; Thomas, P.; Kirchoff, M.; Schwamb, M. E.

    2012-03-01

    Using Cassini mission imagery of the icy satellites of Saturn, numerical simulations, and telescopic observation data we produce a model size frequency distribution for outer solar system impactors spanning tens of meters to thousands of kilometers.

  3. Analytic gravitational-force calculations for models of the Kuiper Belt, with application to the Pioneer anomaly

    SciTech Connect

    Nieto, Michael Martin

    2005-10-15

    We use analytic techniques to study the gravitational force that would be produced by different Kuiper-Belt mass distributions. In particular, we study the 3-dimensional rings (and wedge) whose densities vary as the inverse of the distance, as a constant, as the inverse-squared of the distance, as well as that which varies according to the Boss-Peale model. These analytic calculations yield physical insight into the physics of the problem. They also verify that physically viable models of this type can produce neither the magnitude nor the constancy of the Pioneer anomaly.

  4. 'Everest' Panorama; 20-20 Vision

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site] 'Everest' Panorama 20-20 Vision (QTVR)

    [figure removed for brevity, see original site] 'Everest' Panorama Animation

    If a human with perfect vision donned a spacesuit and stepped onto the martian surface, the view would be as clear as this sweeping panorama taken by NASA's Mars Exploration Rover Spirit. That's because the rover's panoramic camera has the equivalent of 20-20 vision. Earthlings can take a virtual tour of the scenery by zooming in on their computer screens many times to get a closer look at, say, a rock outcrop or a sand drift, without losing any detail. This level of clarity is unequaled in the history of Mars exploration.

    It took Spirit three days, sols 620 to 622 (Oct. 1 to Oct. 3, 2005), to acquire all the images combined into this mosaic, called the 'Everest Panorama,' looking outward in every direction from the true summit of 'Husband Hill.' During that period, the sky changed in color and brightness due to atmospheric dust variations, as shown in contrasting sections of this mosaic. Haze occasionally obscured the view of the hills on the distant rim of Gusev Crater 80 kilometers (50 miles) away. As dust devils swooped across the horizon in the upper right portion of the panorama, the robotic explorer changed the filters on the camera from red to green to blue, making the dust devils appear red, green, and blue. In reality, the dust devils are similar in color to the reddish-brown soils of Mars. No attempt was made to 'smooth' the sky in this mosaic, as has been done in other panoramic-camera mosaics to simulate the view one would get by taking in the landscape all at once. The result is a sweeping vista that allows viewers to observe weather changes on Mars.

    The summit of Husband Hill is a broad plateau of rock outcrops and windblown drifts about 100 meters (300 feet) higher than the surrounding plains of Gusev Crater. In the distance, near the center of the mosaic, is

  5. First light from a kilometer-baseline Scintillation Auroral GPS Array

    PubMed Central

    Datta-Barua, S; Su, Y; Deshpande, K; Miladinovich, D; Bust, G S; Hampton, D; Crowley, G

    2015-01-01

    We introduce and analyze the first data from an array of closely spaced Global Positioning System (GPS) scintillation receivers established in the auroral zone in late 2013 to measure spatial and temporal variations in L band signals at 100–1000 m and subsecond scales. The seven receivers of the Scintillation Auroral GPS Array (SAGA) are sited at Poker Flat Research Range, Alaska. The receivers produce 100 s scintillation indices and 100 Hz carrier phase and raw in-phase and quadrature-phase samples. SAGA is the largest existing array with baseline lengths of the ionospheric diffractive Fresnel scale at L band. With an initial array of five receivers, we identify a period of simultaneous amplitude and phase scintillation. We compare SAGA power and phase data with collocated 630.0 nm all-sky images of an auroral arc and incoherent scatter radar electron precipitation measurements, to illustrate how SAGA can be used in multi-instrument observations for subkilometer-scale studies. Key Points A seven-receiver Scintillation Auroral GPS Array (SAGA) is now at Poker Flat, Alaska SAGA is the largest subkilometer array to enable phase/irregularities studies Simultaneous scintillation, auroral arc, and electron precipitation are observed PMID:26709318

  6. First light from a kilometer-baseline Scintillation Auroral GPS Array

    NASA Astrophysics Data System (ADS)

    Datta-Barua, S.; Su, Y.; Deshpande, K.; Miladinovich, D.; Bust, G. S.; Hampton, D.; Crowley, G.

    2015-05-01

    We introduce and analyze the first data from an array of closely spaced Global Positioning System (GPS) scintillation receivers established in the auroral zone in late 2013 to measure spatial and temporal variations in L band signals at 100-1000 m and subsecond scales. The seven receivers of the Scintillation Auroral GPS Array (SAGA) are sited at Poker Flat Research Range, Alaska. The receivers produce 100 s scintillation indices and 100 Hz carrier phase and raw in-phase and quadrature-phase samples. SAGA is the largest existing array with baseline lengths of the ionospheric diffractive Fresnel scale at L band. With an initial array of five receivers, we identify a period of simultaneous amplitude and phase scintillation. We compare SAGA power and phase data with collocated 630.0 nm all-sky images of an auroral arc and incoherent scatter radar electron precipitation measurements, to illustrate how SAGA can be used in multi-instrument observations for subkilometer-scale studies.

  7. A Low Density for Binary Kuiper Belt Object (26308) 1998 SM165

    NASA Astrophysics Data System (ADS)

    Spencer, John R.; Stansberry, J. A.; Grundy, W. M.; Noll, K. S.

    2006-09-01

    The densities of Kuiper Belt objects provide valuable clues to their composition, internal structure, and origin. To extend our limited knowledge of KBO densities, we have been attempting to obtain radiometric diameters for binary KBOs, which have masses determined from the satellite orbits, using the MIPS mid-IR imager on the Spitzer Space Telescope. Due to higher than expected KBO albedos, and MIPS's lower than expected 70 µm sensitivity, our 2006 campaign concentrated on long exposures on a single target, (26308) 1998 SM165, one of the brightest and warmest known KBO binaries. 7.5 hour integration times at both 24 and 70 µm yielded monochromatic fluxes of 0.11 ± 0.01 mJy at 23.7 microns and 6.1 ± 1.1 mJy at 71.4 microns. From these we derive a relatively model-independent diameter of 287 ± 36 km for the primary and 96 ± 12 km for the satellite, assuming similar albedos. The derived V geometric albedo (using HV = 6.13, Romanishin and Tegler 2006 Icarus 179 523) is 0.07 ± 0.02. The system mass from HST (Margot et al. 2004, DPS 36, 08.03) then yields a system density of 0.51 +0.29 -0.14 g cm-3, comparable to that for KBO (47171) 1999 TC36 (Stansberry et al. 2006, Ap. J. 643, 556). This density is also comparable to that of the similarly-sized planetary satellites Amalthea (D=200 km, ρ=0.86) and Hyperion (D=250 km, ρ=0.6), but much lower than the density of Phoebe (D=200 km, ρ=1.63), and suggests both high porosity and a dominantly water ice composition for this KBO, despite its low albedo and red color. Supporting visible-wavelength lightcurve observations obtained at Lowell Observatory also yielded a revised rotation rate of 8.40 ± 0.05 hours for 1998 SM165.

  8. Simulated MERTIS observation of the Rudaki-Kuiper craters area on Mercury

    NASA Astrophysics Data System (ADS)

    D'Amore, M.; Helbert, J.; Maturilli, A.; Ferrari, S.; Bauch, K.; D'Incecco, P.; Hiesinger, H.; Head, J. W.; Holsclaw, G. M.; Lorin, D. D.; Denevi, B. W.; Stockstill-Cahill, K. R.

    2013-12-01

    The MErcury Radiometer and Thermal infrared Imaging Spectrometer (MERTIS) is part of the payload of the BepiColombo mission. The mission is scheduled for launch in 2015 with arrival at Mercury in 2021. To achieve MERTIS's scientific goals the instrument maps the surface of Mercury with a spatial resolution of 500m for the spectrometer channel and 2km for the radiometer channel. MERTIS spans wavelength ranges of 7-14 and 7-40 μm with its two channels. Among it scientific goals, MERTIS will infer rock-forming minerals, map surface composition, and study surface temperature variations on Mercury with an uncooled microbolometer detector. To exploit the full potential of the unique MERTIS dataset, an extensive calibration campaign has been performed. This includes radiometric, spectral, and geometric calibration. In addition we have performed measurement of analog materials at temperatures of up to 500°C - similar to the peak temperatures expected at Mercury - with the MERTIS qualification model in the Planetary Emissivity Laboratory. These measurements allow for the evaluation of the MERTIS performance in direct comparison with the laboratory spectrometer. They also enable the creation of synthetic MERTIS datasets. For this purpose we use data from the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft as baseline. MESSENGER can provide geological information as well as spectral information in the UV, visible and near-infrared wavelengths range. For a first test we have selected the Kuiper-Rudaki region. The region has been extensively covered by measurements from the MESSENGER spacecraft. Recent analysis of observations by the Mercury Atmospheric and Surface Composition Spectrometer (MASCS) instrument on the MESSENGER spacecraft with an unsupervised hierarchical clustering method shows at global scales two major units: a Polar region (PR) spectrally flat and redder than the equatorial region (ER). The study area is primarily

  9. SYSTEMATIC BIASES IN THE OBSERVED DISTRIBUTION OF KUIPER BELT OBJECT ORBITS

    SciTech Connect

    Jones, R. L.; Parker, J. Wm.; Bieryla, A.; Marsden, B. G.; Gladman, B.; Kavelaars, JJ.; Petit, J.-M.

    2010-06-15

    The orbital distribution of Kuiper Belt objects (KBOs) provides important tests of solar system evolution models. However, our understanding of this orbital distribution can be affected by many observational biases. An important but difficult to quantify bias results from tracking selection effects; KBOs are recovered or lost depending on assumptions made about their orbital elements when fitting the initial (short) observational arc. Quantitatively studying the effects and significance of this bias is generally difficult, because only the objects where the assumptions were correct are recovered and thus available to study 'the problem', and because different observers use different assumptions and methods. We have used a sample of 38 KBOs that were discovered and tracked, bias-free, as part of the Canada-France Ecliptic Plane Survey to evaluate the potential for losing objects based on the two most common orbit and ephemeris prediction sources: the Minor Planet Center (MPC) and the Bernstein and Khushalani (BK) orbit fitting code. In both cases, we use early discovery and recovery astrometric measurements of the objects to generate ephemeris predictions that we then compare to later positional measurements; objects that have large differences between the predicted and actual positions would be unlikely to be recovered and are thus considered 'lost'. We find systematic differences in the orbit distributions which would result from using the two orbit-fitting procedures. In our sample, the MPC-derived orbit solutions lost slightly fewer objects (five out of 38) due to large ephemeris errors at one year recovery, but the objects which were lost belonged to more 'unusual' orbits such as scattering disk objects or objects with semimajor axes interior to the 3:2 resonance. Using the BK code, more objects (seven out of 38) would have been lost due to ephemeris errors, but the lost objects came from a range of orbital regions, primarily the classical belt region. We also

  10. An Icy Kuiper-Belt Around the Young Solar-Type Star HD 181327

    NASA Technical Reports Server (NTRS)

    Lebreton, J.; Augereau, J.-C.; Thi, W.-F.; Roberge, A.; Donaldson, J.; Schneider, G.; Maddison, S. T.; Menard, F.; Riviere-Marichalar, P.; Mathews, G. S.; Kamp, I.; Pinte, C.; Dent, W. R. F.; Barrado, D.; Duchene, G.; Gonzalez, J.-F.; Grady, C. A.; Meeus, G.; Pantin, E.; Williams, J. P.; Woitke, P.

    2011-01-01

    dust disk suggest that it has passed the stage of gaseous planets formation. The dust reveals a population of icy planetesimals, similar to the primitive Edgeworth-Kuiper Belt, that may be a source for the future delivery of water and volatiles onto forming terrestrial planets.

  11. An Icy Kuiper Belt Around the Young Solar-type Star HD 181327

    NASA Technical Reports Server (NTRS)

    Lebreton, J.; Augereau, J.-C.; Thi, W.-F.; Roberge, A.; Donaldson, J; Schneider, G.; Maddison, S. T.; Menard, F.; Riviere-Marichalar, P.; Matthews, G. S.; Kamp, I.; Pinte, C.; Dent, W. R. F.; Barrado, D.; Duchene, G.; Gonzalez, J.-F.; Grady C. A.; Meeus,G.; Pantin, E.; Williams, J. P.; Woitke, P.

    2012-01-01

    constraints on the gas disk, the age of HD 181327 and the properties of the dust disk suggest that it has passed the stage of gaseous planets formation. The dust reveals a population of icy planetesimals, similar to the primitive Edgeworth-Kuiper belt, that may be a source for the future delivery of water and volatiles onto forming terrestrial planets.

  12. MICROWAVE EMISSION FROM THE EDGEWORTH-KUIPER BELT AND THE ASTEROID BELT CONSTRAINED FROM THE WILKINSON MICROWAVE ANISOTROPY PROBE

    SciTech Connect

    Ichikawa, Kazuhide; Fukugita, Masataka

    2011-08-01

    Objects in the Edgeworth-Kuiper Belt and the main asteroid belt should emit microwaves that may give rise to extra anisotropy signals in the multipole of the cosmic microwave background (CMB) experiment. Constraints are derived from the absence of positive detection of such anisotropies for l {approx}< 50, meaning the total mass of Edgeworth-Kuiper Belt objects is smaller than 0.2 M{sub +}. This limit is consistent with the mass extrapolated from the observable population with the size of a {approx}> 15 km, assuming that the small-object population follows the power law in size dN/da {approx} a{sup -q} with the canonical index expected for collisional equilibrium, q {approx_equal} 3.5, with which 23% of the mass is ascribed to objects smaller than are observationally accessible down to grains. A similar argument applied to the main asteroid belt indicates that the grain population should not increase more quickly than q {approx_equal} 3.6 toward smaller radii, if the grain population follows the power law that continues to observed asteroids with larger radii. Both cases are at or only slightly above the limit that can be physically significant, implying the importance of further tightening the CMB anisotropy limit, which may be attained with observation at higher radio frequencies.

  13. Depth of faulting and ancient heat flows in the Kuiper region of Mercury from lobate scarp topography

    NASA Astrophysics Data System (ADS)

    Egea-González, Isabel; Ruiz, Javier; Fernández, Carlos; Williams, Jean-Pierre; Márquez, Álvaro; Lara, Luisa M.

    2012-01-01

    Mercurian lobate scarps are interpreted to be the surface expressions of thrust faults formed by planetary cooling and contraction, which deformed the crust down to the brittle-ductile transition (BDT) depth at the time of faulting. In this work we have used a forward modeling procedure in order to analyze the relation between scarp topography and fault geometries and depths associated with a group of prominent lobate scarps (Santa Maria Rupes and two unnamed scarps) located in the Kuiper region of Mercury for which Earth-based radar altimetry is available. Also a backthrust associated with one of the lobate scarps has been included in this study. We have obtained best fits for depths of faulting between 30 and 39 km; the results are consistent with the previous results for other lobate scarps on Mercury. The so-derived fault depths have been used to calculate surface heat flows for the time of faulting, taking into account crustal heat sources and a heterogeneous surface temperature due to the variable insolation pattern. Deduced surface heat flows are between 19 and 39 mW m-2 for the Kuiper region, and between 22 and 43 mW m-2 for Discovery Rupes. Both BDT depths and heat flows are consistent with the predictions of thermal history models for the range of time relevant for scarp formation.

  14. 24 CFR 100.20 - Definitions.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ..., and Secretary are defined in 24 CFR part 5. Aggrieved person includes any person who— (a) Claims to have been injured by a discriminatory housing practice; or (b) Believes that such person will be injured by a discriminatory housing practice that is about to occur. Broker or Agent includes any...

  15. 20 CFR 638.100 - General.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... services necessary to prepare students to become more responsible, productive, and employable. (Section 421... which are to be established by the Job Corps Director shall be contained in a policy and...

  16. 24 CFR 100.20 - Definitions.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... regarding such offers, solicitations or contracts or any residential real estate-related transactions..., and Secretary are defined in 24 CFR part 5. Aggrieved person includes any person who— (a) Claims to... injured by a discriminatory housing practice that is about to occur. Broker or Agent includes any...

  17. 24 CFR 100.20 - Definitions.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... regarding such offers, solicitations or contracts or any residential real estate-related transactions..., and Secretary are defined in 24 CFR part 5. Aggrieved person includes any person who— (a) Claims to... injured by a discriminatory housing practice that is about to occur. Broker or Agent includes any...

  18. 24 CFR 100.20 - Definitions.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... regarding such offers, solicitations or contracts or any residential real estate-related transactions..., and Secretary are defined in 24 CFR part 5. Aggrieved person includes any person who— (a) Claims to... injured by a discriminatory housing practice that is about to occur. Broker or Agent includes any...

  19. 24 CFR 100.20 - Definitions.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... regarding such offers, solicitations or contracts or any residential real estate-related transactions..., and Secretary are defined in 24 CFR part 5. Aggrieved person includes any person who— (a) Claims to... injured by a discriminatory housing practice that is about to occur. Broker or Agent includes any...

  20. 50 CFR 20.100 - General provisions.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... General provisions. (a) The taking, possession, transportation, and other uses of migratory game birds by.... Migratory game bird population levels, including production and habitat conditions, vary annually. These... migratory game birds to permissible levels. (b) The development of these schedules involves annual...

  1. 50 CFR 20.100 - General provisions.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... General provisions. (a) The taking, possession, transportation, and other uses of migratory game birds by.... Migratory game bird population levels, including production and habitat conditions, vary annually. These... migratory game birds to permissible levels. (b) The development of these schedules involves annual...

  2. 50 CFR 20.100 - General provisions.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... General provisions. (a) The taking, possession, transportation, and other uses of migratory game birds by.... Migratory game bird population levels, including production and habitat conditions, vary annually. These... migratory game birds to permissible levels. (b) The development of these schedules involves annual...

  3. Experimentally determined volumetric properties of CO{sub 2} + CH{sub 4} + N{sub 2} mixtures at 20-100 MPa and 323-573 K. Chapter 3

    SciTech Connect

    Seitz, J.C.; Blencoe, J.G.; Bodnar, R.J.

    1994-12-31

    The densities of C0{sub 2}+CH{sub 4}+N{sub 2} mixtures were measured at 20--100 MPa, 323--573 K using a custom-designed high-pressure, high-temperature vibrating-tube densimeter. Molar volumes and excess molar volumes (V{sub m}{sup E}) were calculated from the experimental data. Although (V{sub m}{sup E}) is generally positive, negative deviations are observed in ternary mixtures with compositions close to those of binary mixtures that exhibit negative deviations. (V{sub m}{sup E}) generally decreases as pressure increases from 20 to 100 MPa. As temperature increases, (V{sub m}{sup E}) increases until it reaches a maximum around 473 K, and then it decreases moderately as temperature is further increased. (V{sub m}{sup E}) is typically between 0 and 4 per cent of the total volume of the mixture. Predictions of (V{sub m}{sup E}) for ternary mixtures may be made from experimental data for the binary subsystems. Comparison with experimental data indicates that these methods are reasonably accurate for predicting the volumetric properties of ternary gas mixtures.

  4. Scaling Soil Moisture from Meter to Kilometer Scale Using P-Band Radar

    NASA Astrophysics Data System (ADS)

    Cuenca, Richard; Hagimoto, Yutaka; Moghaddam, Mahta

    2015-04-01

    Correct evaluation of regional scale soil moisture content remains one of the challenging limitations for reasonable prediction of regional scale carbon fluxes. The airborne P-band radar of the NASA AirMOSS project retrieves relatively high spatial resolution dielectric constant signals over an experimental domain of 100 by 25-km sensitive to a depth of on the order of 75-cm. The continuous (15-min time resolution over multiple years) ground-based monitoring transects over nine experimental sites in North America are on the spatial scale of 100-m horizontal and 1-m vertical in seven depth layers. The efficient data management scheme of the ground-based data and the experimental protocol of the airborne P-band radar flights are described. Correlation of the distinct seasonal soil moisture signals of the grassland, deciduous, evergreen and tropical forest monitoring sites with the P-band radar dielectric retrieval are demonstrated. Derivation of robust soil water hydraulic properties based on the extensive database developed at the monitoring sites is described.

  5. De-biased Populations of Kuiper Belt Objects from the Deep Ecliptic Survey

    NASA Astrophysics Data System (ADS)

    Adams, E. R.; Gulbis, A. A. S.; Elliot, J. L.; Benecchi, S. D.; Buie, M. W.; Trilling, D. E.; Wasserman, L. H.

    2014-09-01

    The Deep Ecliptic Survey (DES) was a survey project that discovered hundreds of Kuiper Belt objects from 1998 to 2005. Extensive follow-up observations of these bodies has yielded 304 objects with well-determined orbits and dynamical classifications into one of several categories: Classical, Scattered, Centaur, or 16 mean-motion resonances with Neptune. The DES search fields are well documented, enabling us to calculate the probability on each frame of detecting an object with its particular orbital parameters and absolute magnitude at a randomized point in its orbit. The detection probabilities range from a maximum of 0.32 for the 3:2 resonant object 2002 GF 32 to a minimum of 1.5 × 10-7 for the faint Scattered object 2001 FU 185. By grouping individual objects together by dynamical classes, we can estimate the distributions of four parameters that define each class: semimajor axis, eccentricity, inclination, and object size. The orbital element distributions (a, e, and i) were fit to the largest three classes (Classical, 3:2, and Scattered) using a maximum likelihood fit. Using the absolute magnitude (H magnitude) as a proxy for the object size, we fit a power law to the number of objects versus H magnitude for eight classes with at least five detected members (246 objects). The Classical objects are best fit with a power-law slope of α = 1.02 ± 0.01 (observed from 5 <= H <= 7.2). Six other dynamical classes (Scattered plus five resonances) have consistent magnitude distribution slopes with the Classicals, provided that the absolute number of objects is scaled. Scattered objects are somewhat more numerous than Classical objects, while there are only a quarter as many 3:2 objects as Classicals. The exception to the power law relation is the Centaurs, which are non-resonant objects with perihelia closer than Neptune and therefore brighter and detectable at smaller sizes. Centaurs were observed from 7.5 < H < 11, and that population is best fit by a power law

  6. De-biased populations of Kuiper belt objects from the deep ecliptic survey

    SciTech Connect

    Adams, E. R.; Benecchi, S. D.; Gulbis, A. A. S.; Elliot, J. L.; Buie, M. W.; Trilling, D. E.; Wasserman, L. H.

    2014-09-01

    The Deep Ecliptic Survey (DES) was a survey project that discovered hundreds of Kuiper Belt objects from 1998 to 2005. Extensive follow-up observations of these bodies has yielded 304 objects with well-determined orbits and dynamical classifications into one of several categories: Classical, Scattered, Centaur, or 16 mean-motion resonances with Neptune. The DES search fields are well documented, enabling us to calculate the probability on each frame of detecting an object with its particular orbital parameters and absolute magnitude at a randomized point in its orbit. The detection probabilities range from a maximum of 0.32 for the 3:2 resonant object 2002 GF {sub 32} to a minimum of 1.5 × 10{sup –7} for the faint Scattered object 2001 FU {sub 185}. By grouping individual objects together by dynamical classes, we can estimate the distributions of four parameters that define each class: semimajor axis, eccentricity, inclination, and object size. The orbital element distributions (a, e, and i) were fit to the largest three classes (Classical, 3:2, and Scattered) using a maximum likelihood fit. Using the absolute magnitude (H magnitude) as a proxy for the object size, we fit a power law to the number of objects versus H magnitude for eight classes with at least five detected members (246 objects). The Classical objects are best fit with a power-law slope of α = 1.02 ± 0.01 (observed from 5 ≤ H ≤ 7.2). Six other dynamical classes (Scattered plus five resonances) have consistent magnitude distribution slopes with the Classicals, provided that the absolute number of objects is scaled. Scattered objects are somewhat more numerous than Classical objects, while there are only a quarter as many 3:2 objects as Classicals. The exception to the power law relation is the Centaurs, which are non-resonant objects with perihelia closer than Neptune and therefore brighter and detectable at smaller sizes. Centaurs were observed from 7.5 < H < 11, and that population is best

  7. A perceptual channel for information transfer over kilometer distances Historical perspective and recent research. [extrasensory perception

    NASA Technical Reports Server (NTRS)

    Puthoff, H. E.; Targ, R.

    1976-01-01

    For more than 100 years, scientists have attempted to determine the truth or falsity of claims for the existence of a perceptual channel whereby certain individuals are able to perceive and describe remote data not presented to any known sense. This paper presents an outline of the history of scientific inquiry into such so-called paranormal perception and surveys the current state of the art in parapsychological research in the United States and abroad. The nature of this perceptual channel is examined in a series of experiments carried out in the Electronics and Bioengineering Laboratory of Stanford Research Institute. The perceptual modality most extensively investigated is the ability of both experienced subjects and inexperienced volunteers to view, by innate mental processes, remote geographical or technical targets including buildings, roads, and laboratory apparatus. The accumulated data indicate that the phenomenon is not a sensitive function of distance, and Faraday cage shielding does not in any apparent way degrade the quality and accuracy of perception. On the basis of this research, some areas of physics are suggested from which a description or explanation of the phenomenon could be forthcoming.

  8. Successful 2,000-Kilometer International Transfer of an Infant Receiving Extracorporeal Membrane Oxygenation for Severe Respiratory Failure.

    PubMed

    Brown, Kilian; Dunne, Ben; Festa, Marino; La Hei, Erik; Karpelowsky, Jonathan; Dando, Hayden; Orr, Yishay

    2016-08-01

    There is minimal reported experience with long-range retrieval of pediatric patients receiving extracorporeal membrane oxygenation (ECMO) support. We report the case of a 10-month old boy with necrotizing staphylococcal pneumonia complicated by a bronchopleural fistula, who was successfully retrieved and transported while receiving ECMO to our unit in Sydney, Australia, from a referring hospital 2,000 kilometers away in the Pacific Islands. He was successfully weaned from ECMO to receive single-lung ventilation after 13 days, and he underwent surgical repair of his bronchopleural fistula through a thoracotomy 3 days after decannulation. He has made a full recovery. PMID:27449448

  9. Electroacupuncture-Like Stimulation at the Baihui (GV20) and Dazhui (GV14) Acupoints Protects Rats against Subacute-Phase Cerebral Ischemia-Reperfusion Injuries by Reducing S100B-Mediated Neurotoxicity

    PubMed Central

    Cheng, Chin-Yi; Lin, Jaung-Geng; Tang, Nou-Ying; Kao, Shung-Te; Hsieh, Ching-Liang

    2014-01-01

    Objectives The purpose of this study was to evaluate the effects of electroacupuncture-like stimulation at the Baihui (GV20) and Dazhui (GV14) acupoints (EA at acupoints) during the subacute phase of cerebral ischemia-reperfusion (I/R) injury and to establish the neuroprotective mechanisms involved in the modulation of the S100B-mediated signaling pathway. Methods The experimental rats were subjected to middle cerebral artery occlusion (MCAo) for 15 min followed by 1 d or 7 d of reperfusion. EA at acupoints was applied 1 d postreperfusion then once daily for 6 consecutive days. Results We observed that 15 min of MCAo caused delayed infarct expansion 7 d after reperfusion. EA at acupoints significantly reduced the cerebral infarct and neurological deficit scores. EA at acupoints also downregulated the expression of the glial fibrillary acidic protein (GFAP), S100B, nuclear factor-κB (NF-κB; p50), and tumor necrosis factor-α (TNF-α), and reduced the level of inducible nitric oxide synthase (iNOS) and apoptosis in the ischemic cortical penumbra 7 d after reperfusion. Western blot analysis showed that EA at acupoints significantly downregulated the cytosolic expression of phospho-p38 MAP kinase (p-p38 MAP kinase), tumor necrosis factor receptor type 1-associated death domain (TRADD), Fas-associated death domain (FADD), cleaved caspase-8, and cleaved caspase-3 in the ischemic cortical penumbra 7 d after reperfusion. EA at acupoints significantly reduced the numbers of GFAP/S100B and S100B/nitrotyrosine double-labeled cells. Conclusion Our study results indicate that EA at acupoints initiated 1 d postreperfusion effectively downregulates astrocytic S100B expression to provide neuroprotection against delayed infarct expansion by modulating p38 MAP kinase-mediated NF-κB expression. These effects subsequently reduce oxidative/nitrative stress and inhibit the TNF-α/TRADD/FADD/cleaved caspase-8/cleaved caspase-3 apoptotic pathway in the ischemic cortical penumbra 7 d

  10. Ultraviolet interstellar lines in the spectrum of Pi Scorpii recorded at 2 kilometers per second resolution

    NASA Technical Reports Server (NTRS)

    Joseph, Charles L.; Jenkins, Edward B.

    1991-01-01

    A spectrum of Pi Scorpii has been recorded from 1003 to 1172 A with a maximum SNR of about 20 and a velocity resolution of 2.4 km/s. Three types of H I as well as two discrete H II regions are distinguished in velocity space, allowing independent analyses of physical conditions and abundances for the individual gas components. A direct evaluation of optical depths and column densities across the absorption features is applied for the first time to the dominant ionization stage of Fe, Si, and P. Based on an analysis of the spectrum, it is concluded that all of the Ti II absorption seen toward Pi Sco arises in the warm, neutral intercloud medium while the other elements have their maximum absorption associated with cold clouds. A conservative value of log delta less than -3.4 is inferred for the Ti depletion in the cold clouds, a value more extreme than any integrated, line-of-sight measurement made to date.

  11. The densities of halite-saturated WIPP-A and NBT-6 brines and their NaCl contents in weight percent, molal, and molar units from 20 to 100 degrees C

    USGS Publications Warehouse

    Chou, I-Ming; Buizinga, B.; Clynne, M.A.; Potter, R.W.

    1982-01-01

    A series of density measurements has been performed at 30?, 50?, 70?, and 90?C for halite-undersaturated WIPP-A and NBT-6 brines with various NaCl contents approaching saturation. The densities of halite-saturated WIPP-A and NBT-6 brines were obtained by extrapolating these measured densities to halite saturation points. The maximum difference between the densities obtained in this Fashion and those calculated from the model of Potter and Haas is 0.015 g/cm3. The NaCl contents in halite-saturated WIPP-A and NBT-6 brines are reported in wt %, molal, and molar units from 20? to 100?C.

  12. Impact of Universal Plasma and Energetic Particle Processes on Icy Bodies of the Kuiper Belt and the Oort Cloud

    NASA Technical Reports Server (NTRS)

    Cooper, John F.; Richardson, J. D.; Hill, M. E.; Sturner, S. J.

    2008-01-01

    Modeling of space plasma and energetic particle interactions with icy bodies of the outer solar system is simplified when there is commonality of the underlying source, acceleration, and transport processes in spatially distinct regions from the supersonic heliosphere through the heliosheath into the local interstellar medium (LISM). Current trends in the Voyager heliosheath measurements suggest strong commonality to processes in the LISM. The Fisk-Gloeckler "universal" spectrum at suprathermal energies apparently plays a strong role in coupling the plasma and high energy particle regimes in the spatial and energetic transitions from the outer heliosphere to the LISM. Dominant processes in consecutive energy regimes project to varying effects versus irradiation depth on exposed upper surfaces of airless small icy bodies and to upper atmospheres of larger bodies such as Titan and Pluto. Relative absence of the universal suprathermal spectrum in the mid-heliospheric region of the classical Kuiper Belt may profoundly affect surface color diversity of icy bodies in this region.

  13. Non-isothermal decomposition kinetics, heat capacity and thermal safety of 37.2/44/16/2.2/0.2/0.4-GAP/CL-20/Al/N-100/PCA/auxiliaries mixture.

    PubMed

    Zhang, Jiao-Qiang; Gao, Hong-Xu; Ji, Tie-Zheng; Xu, Kang-Zhen; Hu, Rong-Zu

    2011-10-15

    The specific heat capacity (C(p)) of 37.2/44/16/2.2/0.2/0.4-GAP/CL-20/Al/N-100/PCA/auxiliaries mixture was determined with the continuous C(p) mode of microcalorimeter. The equation of C(p) with temperature was obtained. The standard molar heat capacity of GAP/CL-20/Al/N-100/PCA/auxiliaries mixture was 1.225 J mol(-1)K(-1) at 298.15K. With the help of the peak temperature (T(p)) from the non-isothermal DTG curves of the mixture at different heating rates (β), the apparent activation energy (E(k) and E(o)) and pre-exponential constant (A(K)) of thermal decomposition reaction obtained by Kissinger's method and Ozawa's method. Using density (ρ) and thermal conductivity (λ), the decomposition heat (Q(d), taking half-explosion heat), Zhang-Hu-Xie-Li's formula, the values (T(e0) and T(p0)) of T(e) and T(p) corresponding to β → 0, thermal explosion temperature (T(be) and T(bp)), adiabatic time-to-explosion (t(TIad)), 50% drop height (H(50)) of impact sensitivity, and critical temperature of hot-spot initiation (T(cr,hot spot)) of thermal explosion of the mixture were calculated. The following results of evaluating the thermal safety of the mixture were obtained: T(be) = 441.64K, T(bp) = 461.66 K, t(Tlad) = 78.0 s (n = 2), t(Tlad) = 74.87 s (n = 1), t(Tlad) = 71.85 s (n = 0), H(50) = 21.33 cm. PMID:21820242

  14. Numerical Simulations Of Catastrophic Disruption Of Porous Bodies: Application To Dark-type Asteroids And Kuiper-belt Family Formation

    NASA Astrophysics Data System (ADS)

    Michel, Patrick; Jutzi, M.; Richardson, D. C.; Benz, W.

    2010-10-01

    Asteroids of dark (e.g. C, D) taxonomic classes as well as Kuiper Belt objects and comets are believed to have high porosity, not only in the form of large voids but also in the form of micro-pores. The presence of such microscale porosity introduces additional physics in the impact process. We have enhanced our 3D SPH hydrocode, used to simulate catastrophic breakups, with a model of porosity [1] and validated it at small scale by comparison with impact experiments on pumice targets [2]. Our model is now ready to be applied to a large range of problems. In particular, accounting for the gravitational phase of an impact, we can study the formation of dark-type asteroid families, such as Veritas, and Kuiper-Belt families, such as Haumea. Recently we characterized for the first time the catastrophic impact energy threshold, usually called Q*D, as a function of the target's diameter, porosity, material strength and impact speed [3]. Regarding the mentioned families, our preliminary results show that accounting for porosity leads to different outcomes that may better represent their properties and constrain their definition. In particular, for Veritas, we find that its membership may need some revision [4]. The parameter space is still large, many interesting families need to be investigated and our model will be applied to a large range of cases. PM, MJ and DCR acknowledge financial support from the French Programme National de Planétologie, NASA PG&G "Small Bodies and Planetary Collisions" and NASA under Grant No. NNX08AM39G issued through the Office of Space Science, respectively. [1] Jutzi et al. 2008. Icarus 198, 242-255; [2] Jutzi et al. 2009. Icarus 201, 802-813; [3] Jutzi et al. 2010. Fragment properties at the catastrophic disruption threshold: The effect of the parent body's internal structure, Icarus 207, 54-65; [4] Michel et al. 2010. Icarus, submitted.

  15. On the use of Video Camera Systems in the Detection of Kuiper Belt Objects by Stellar Occultations

    NASA Astrophysics Data System (ADS)

    Subasinghe, Dilini

    2012-10-01

    Due to the distance between us and the Kuiper Belt, direct detection of Kuiper Belt Objects (KBOs) is not currently possible for objects less than 10 km in diameter. Indirect methods such as stellar occultations must be employed to remotely probe these bodies. The size, shape, as well as atmospheric properties and ring system information of a body (if any), can be collected through observations of stellar occultations. This method has been previously used with some success - Roques et al. (2006) detected 3 Trans-Neptunian objects; Schlichting et al. (2009) detected a single object in archival data. However, previous assessments of KBO occultation detection rates have been calculated only for telescopes - we extend this method to video camera systems. Building on Roques & Moncuquet (2000), we present a derivation that can be applied to any video camera system, taking into account camera specifications and diffraction effects. This allows for a determination of the number of observable KBO occultations per night. Example calculations are presented for some of the automated meteor camera systems currently in use at the University of Western Ontario. The results of this project will allow us to refine and improve our own camera system, as well as allow others to enhance their systems for KBO detection. Roques, F., Doressoundiram, A., Dhillon, V., Marsh, T., Bickerton, S., Kavelaars, J. J., Moncuquet, M., Auvergne, M., Belskaya, I., Chevreton, M., Colas, F., Fernandez, A., Fitzsimmons, A., Lecacheux, J., Mousis, O., Pau, S., Peixinho, N., & Tozzi, G. P. (2006). The Astronomical Journal, 132(2), 819-822. Roques, F., & Moncuquet, M. (2000). Icarus, 147(2), 530-544. Schlichting, H. E., Ofek, E. O., Wenz, M., Sari, R., Gal-Yam, A., Livio, M., Nelan, E., & Zucker, S. (2009). Nature, 462(7275), 895-897.

  16. Enhanced therapeutic anti-inflammatory effect of betamethasone on topical administration with low-frequency, low-intensity (20 kHz, 100 mW/cm(2)) ultrasound exposure on carrageenan-induced arthritis in a mouse model.

    PubMed

    Cohen, Gadi; Natsheh, Hiba; Sunny, Youhan; Bawiec, Christopher R; Touitou, Elka; Lerman, Melissa A; Lazarovici, Philip; Lewin, Peter A

    2015-09-01

    The purpose of this work was to investigate whether low-frequency, low-intensity (20 kHz, <100 mW/cm(2), spatial-peak, temporal-peak intensity) ultrasound, delivered with a lightweight (<100 g), tether-free, fully wearable, battery-powered applicator, is capable of reducing inflammation in a mouse model of rheumatoid arthritis. The therapeutic, acute, anti-inflammatory effect was estimated from the relative swelling induced in mice hindlimb paws. In an independent, indirect approach, the inflammation was bio-imaged by measuring glycolytic activity with near-infrared labeled 2-deoxyglucose. The outcome of the experiments indicated that the combination of ultrasound exposure and topical application of 0.1% (w/w) betamethasone gel resulted in statistically significantly (p < 0.05) enhanced anti-inflammatory activity in comparison with drug or ultrasound treatment alone. The present study underscores the potential benefits of low-frequency, low-intensity ultrasound-assisted drug delivery. However, the proof of concept presented indicates the need for additional experiments to systematically evaluate and optimize the potential of, and the conditions for, tolerable low-frequency, low-intensity ultrasound-promoted non-invasive drug delivery. PMID:26003010

  17. Influence of injection mode on transport properties in kilometer-scale three-dimensional discrete fracture networks

    SciTech Connect

    Hyman, Jeffrey De'Haven; Painter, S. L.; Viswanathan, H.; Makedonska, N.; Karra, S.

    2015-09-12

    We investigate how the choice of injection mode impacts transport properties in kilometer-scale three-dimensional discrete fracture networks (DFN). The choice of injection mode, resident and flux-weighted, is designed to mimic different physical phenomena. It has been hypothesized that solute plumes injected under resident conditions evolve to behave similarly to solutes injected under flux-weighted conditions. Previously, computational limitations have prohibited the large-scale simulations required to investigate this hypothesis. We investigate this hypothesis by using a high-performance DFN suite, dfnWorks, to simulate flow in kilometer-scale three-dimensional DFNs based on fractured granite at the Forsmark site in Sweden, and adopt a Lagrangian approach to simulate transport therein. Results show that after traveling through a pre-equilibrium region, both injection methods exhibit linear scaling of the first moment of travel time and power law scaling of the breakthrough curve with similar exponents, slightly larger than 2. Lastly, the physical mechanisms behind this evolution appear to be the combination of in-network channeling of mass into larger fractures, which offer reduced resistance to flow, and in-fracture channeling, which results from the topology of the DFN.

  18. Influence of injection mode on transport properties in kilometer-scale three-dimensional discrete fracture networks

    DOE PAGESBeta

    Hyman, Jeffrey De'Haven; Painter, S. L.; Viswanathan, H.; Makedonska, N.; Karra, S.

    2015-09-12

    We investigate how the choice of injection mode impacts transport properties in kilometer-scale three-dimensional discrete fracture networks (DFN). The choice of injection mode, resident and flux-weighted, is designed to mimic different physical phenomena. It has been hypothesized that solute plumes injected under resident conditions evolve to behave similarly to solutes injected under flux-weighted conditions. Previously, computational limitations have prohibited the large-scale simulations required to investigate this hypothesis. We investigate this hypothesis by using a high-performance DFN suite, dfnWorks, to simulate flow in kilometer-scale three-dimensional DFNs based on fractured granite at the Forsmark site in Sweden, and adopt a Lagrangian approachmore » to simulate transport therein. Results show that after traveling through a pre-equilibrium region, both injection methods exhibit linear scaling of the first moment of travel time and power law scaling of the breakthrough curve with similar exponents, slightly larger than 2. Lastly, the physical mechanisms behind this evolution appear to be the combination of in-network channeling of mass into larger fractures, which offer reduced resistance to flow, and in-fracture channeling, which results from the topology of the DFN.« less

  19. Synergies Between The Next Generation Of Optical/ir Sky Survey Projects And The Square Kilometer Array

    NASA Astrophysics Data System (ADS)

    Chambers, Kenneth C.

    2007-12-01

    There are significant scientific synergies between proposed facilities making up the Square Kilometer Array and its precursor pathfinders, including the EVLA, the Allen Telescope, and LOFAR, and upcoming Optical/NIR Synoptic Survey Telescopes such as the Pan-STARRS Telescopes (PS1, PS4, PSn), and the LSST Corporation Telescope. Commissioning data from the PS1 System will be presented along with discussion of lessons learned to date from commissioning and issues arising from the start of the PS1 Science Mission this spring. The approach of the PS1 Science Consortium towards survey strategies and the synergies that arise from designing observational data sets to meet diverse science goals and the challenges of data reduction and coordinated scientific analysis tools in the epoch of multiple petabyte datasets will be presented. In particular we will focus on the scientific benefits of coordinating Optical/IR synoptic sky surveys such as Pan-STARRS and LSST with the SKA pathfinders and the proposed mid-frequency Radio Synoptic Survey Telescope as a component of the Square Kilometer Array. These include substantial gains for fundamental science across diverse physical and astrophysical fields of study and including both static sky and time domain multi-wavelength programs.

  20. The influence of breast support on torso, pelvis and arm kinematics during a five kilometer treadmill run.

    PubMed

    Milligan, Alexandra; Mills, Chris; Corbett, Jo; Scurr, Joanna

    2015-08-01

    Many women wear sports bras due to positive benefits associated with these garments (i.e. reduction in breast movement and breast pain), however the effects these garments have on upper body running kinematics has not been investigated. Ten female participants (32 DD or 34 D) completed two five kilometer treadmill runs (9 km h(-1)), once in a low and once in a high breast support. The range of motion (ROM) and peak torso, pelvis, and upper arm Cardan joint angles were calculated over five gait cycles during a five kilometer run. Peak torso yaw, peak rotation of the pelvis, peak pelvis obliquity, ROM in rotation of the pelvis, and ROM in upper arm extension were significant, but marginally reduced when participants ran in the high breast support. The running kinematics reported in the high breast support condition more closely align with economical running kinematics previously defined in the literature, therefore, running in a high breast support may be more beneficial to female runners, with a high breast support advocated for middle distance runners. PMID:26079773

  1. Influence of Injection Mode on Transport Properties in Kilometer-Scale Three-Dimensional Discrete Fracture Networks

    DOE PAGESBeta

    Hyman, Jeffrey; Painter, Scott L; Viswanathan, Hari; Makedonska, Nataliia; Karra, Satish

    2015-01-01

    We investigate how the choice of injection mode impacts transport properties in kilometer-scale three-dimensional discrete fracture networks (DFN). The choice of injection mode, resident or flux-weighted, is designed to mimic different physical phenomena. It has been hypothesized that solute plumes injected under resident conditions evolve to behave similarly to solutes injected under flux-weighted conditions. Previously, computational limitations have prohibited the large scale simulations required to investigate this hypothesis. We investigate this hypothesis by using a high performance DFN suite, dfnWorks, to simulate flow in kilometer-scale three-dimensional DFNs based on fractured granite at the Forsmark site in Sweden, and adopt amore » Lagrangian approach to simulate transport therein. Results show that a after traveling through a pre-equilibrium region both injection methods exhibit linear scaling of the first moment of travel time and power law scaling of the breakthrough curve with similar exponents, slightly larger than two. The physical mechanisms behind this evolution appear to be the combination of in-network channeling of mass into larger fractures which o er reduced resistance to flow and in-fracture channeling that results from the topology of the DFN.« less

  2. Influence of Injection Mode on Transport Properties in Kilometer-Scale Three-Dimensional Discrete Fracture Networks

    SciTech Connect

    Hyman, Jeffrey; Painter, Scott L; Viswanathan, Hari; Makedonska, Nataliia; Karra, Satish

    2015-01-01

    We investigate how the choice of injection mode impacts transport properties in kilometer-scale three-dimensional discrete fracture networks (DFN). The choice of injection mode, resident or flux-weighted, is designed to mimic different physical phenomena. It has been hypothesized that solute plumes injected under resident conditions evolve to behave similarly to solutes injected under flux-weighted conditions. Previously, computational limitations have prohibited the large scale simulations required to investigate this hypothesis. We investigate this hypothesis by using a high performance DFN suite, dfnWorks, to simulate flow in kilometer-scale three-dimensional DFNs based on fractured granite at the Forsmark site in Sweden, and adopt a Lagrangian approach to simulate transport therein. Results show that a after traveling through a pre-equilibrium region both injection methods exhibit linear scaling of the first moment of travel time and power law scaling of the breakthrough curve with similar exponents, slightly larger than two. The physical mechanisms behind this evolution appear to be the combination of in-network channeling of mass into larger fractures which o er reduced resistance to flow and in-fracture channeling that results from the topology of the DFN.

  3. Photographer: JPL P-21739 BW Range: 4.7 million kilometers (2.9 million miles) This picture of Io

    NASA Technical Reports Server (NTRS)

    1979-01-01

    Photographer: JPL P-21739 BW Range: 4.7 million kilometers (2.9 million miles) This picture of Io was taken as Voyager 2 closes in on the Jovian system. Scientists are studying these distant views of Io for evidences of changes since Voyager 1 observations in March of 79. Voyager 1 discovered that Io, the innermost of the Galilean satellites, is the most volcanically active body yet seen in the solar system, surpassing even earth. In this picture, the first volcano discovered by Voyager 1 is again visible in the lower left portion of the disk as a dark oval with a dark spot in the center. In March, this volcano appeared as a heart-shaped marking, not a symmetrical oval. Scientists believe that the non-symmetric markings earlier resulted from a constriction in the mouth of the volcanic vent causing erupting material to extrude preferentially in certain directions. Apparently, the volcanic eruptive activity, which sends material to altitudes of 280 kilometers (175 miles) or more above this volcano, has changed the vent geometry or dislodged an obstruction. Such changes in the form of eruptive fountains are common in terrestial volcanos, although on a much smaller scale than on Io.

  4. Eltanin: Ground Truth for Kilometer-Sized Deep-Ocean Impacts (Invited)

    NASA Astrophysics Data System (ADS)

    Kyte, F. T.; Gersonde, R.; Kuhn, G.

    2009-12-01

    Deposits of the late Pliocene (2.5 Ma) Eltanin impact are unique in the known geological record. The only known example of a km-sized asteroid to impact a deep-ocean (5 km) basin, is the most meterorite-rich locality known on Earth. This was discovered as an Ir anomaly in sediments from three cores collected in the SE Pacific in 1965 by the USNS Eltanin. Subsequently, two expeditions of the R/V Polarstern in 1995 and 2001 have conducted geological and geophysical investigations in the impact region. An area of ~80,000 km2 has been mapped in some detail, and deposits from the impact are found in 23 cores spanning a region extending 660 (E-W) by 250 km (N-S). We find a central region 50 to 100 km across, near the Freeden Seamounts (57.3S, 90.5W), where sediments as old as Eocene have been ripped up (perhaps to basement) and redeposited by the impact into a chaotic mix of pebble to boulder-sized fragments. This is overlain by a fining upward sequence of sediments with laminations and some cross-bedding consistent with deposition in a high-energy flow regime. Near the top of this impact deposit, sub mm- to cm-sized meteoritic ejecta is mixed into the disturbed sediment. This ejecta is composed of 90% shock-melted asteroid and 10% unmelted meteorite fragments from the lo-metal mesosiderite asteroid. The amount of meteoritic ejecta in 13 cores from the central region record deposition of 3 to 50 kg of asteroid material per square meter. Km-sized impacts are fairly common on geological timescales, occurring a few times per m.y., so one or two other similar-sized, and several smaller projectiles likely hit the Pacific basin since the Late Pliocene. Undoubtedly, this is not the only such impact collected in deep-sea cores; it is unique only in that it has been recognized. Eltanin thus serves as type section for identifying ocean-impact deposits at other localities. Projectiles of this size cannot penetrate to the ocean floor and indeed there is no chemical evidence in the

  5. Properties of the +70 kilometers per second cloud toward HD 203664

    NASA Technical Reports Server (NTRS)

    Sembach, Kenneth R.

    1995-01-01

    I present high-resolution International Ultraviolet Explorer (IUE) spectra of the ultraviolet absorption in an intermediate-velocity interstellar cloud (nu(sub LSR) approximately equal to +70 km/s) toward HD 203664. The combined, multiple IUE images result in spectra with S/N = 15-40 and resolutions of approximately 20-25 km/s. The intermediate-velocity cloud absorption is present in ultraviolet lines of C II, C II(sup *), C IV, N I, O I, Mg I, Mg II, Al II, Al III, Si II, Si III, Si IV, S II, Cr II, Mn II, Fe II, and Zn II. The relative abundances of low-ionization species suggest an electron density of 0.15-0.34/cu cm and a temperature of 5300-6100 K in the neutral and weakly ionized gas. Given the presence of high-ionization gas tracers such as Si IV and C IV, ionized portions of the cloud probably contribute to the relatively large values of n(sub e) derived from measurements of the lower ionization species. The high-ionization species in the cloud have an abundance ratio, N(C IV)/N(Si IV) approximately equal to 4.5, similar to that inferred for collisionally ionized cloud interfaces at temperatures near 10(exp 5) K along other sight lines. When referenced to sulfur, the abundances of most elements in the cloud are within a factor of 5 of their solar values, which suggests that the +70 km/s gas has a previous origin in the Galactic disk despite a recent determination by Little et al. that the cloud lies at a distance of 200-1500 pc below the Galactic plane. I have checked this result against a model of the ionization for the diffuse ionized gas layer of the Galaxy and find that this conclusion is essentially unchanged as long as the ionization parameter is low as implied by the abundances of adjoining ionization states of aluminum and silicon. The processes responsible for the production of highly ionized gas in the +70 km/s cloud appear to be able to account for the inferred dust grain destruction as well.

  6. 21 CFR 100.100 - Misleading containers.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 2 2011-04-01 2011-04-01 false Misleading containers. 100.100 Section 100.100 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION GENERAL Misbranding for Reasons Other Than Labeling § 100.100 Misleading containers. In accordance with section 403(d) of the...

  7. 21 CFR 100.100 - Misleading containers.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 2 2014-04-01 2014-04-01 false Misleading containers. 100.100 Section 100.100 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION GENERAL Misbranding for Reasons Other Than Labeling § 100.100 Misleading containers. In accordance with section 403(d) of the...

  8. 21 CFR 100.100 - Misleading containers.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 2 2012-04-01 2012-04-01 false Misleading containers. 100.100 Section 100.100 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION GENERAL Misbranding for Reasons Other Than Labeling § 100.100 Misleading containers. In accordance with section 403(d) of the...

  9. 21 CFR 100.100 - Misleading containers.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 2 2013-04-01 2013-04-01 false Misleading containers. 100.100 Section 100.100 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION GENERAL Misbranding for Reasons Other Than Labeling § 100.100...

  10. Continuous gradient temperature Raman spectroscopy of the long chain polyunsaturated fatty acids docosapentaenoic (DPA, 22:5n-6) and docosahexaenoic (DHA; 22:6n-3) from -100 to 20° C

    NASA Astrophysics Data System (ADS)

    Broadhurst, C. Leigh; Schmidt, Walter F.; Kim, Moon S.; Nguyen, Julie K.; Qin, Jianwei; Chao, Kuanglin; Bauchan, Gary L.; Shelton, Daniel R.

    2016-05-01

    The structural, cognitive and visual development of the human brain and retina strictly require long-chain polyunsaturated fatty acids (LC-PUFA). Excluding water, the mammalian brain is about 60% lipid. One of the great unanswered questions with respect to biological science in general is the absolute necessity of the LC-PUFA docosahexaenoic acid (DHA; 22:6n-3) in these fast signal processing tissues. A lipid of the same chain length with just one less diene group, docosapentaenoic acid (DPA; 22:5n-6) is fairly abundant in terrestrial food chains yet cannot substitute for DHA. Gradient Temperature Raman spectroscopy (GTRS) applies the temperature gradients utilized in differential scanning calorimetry to Raman spectroscopy, providing a straightforward technique to identify molecular rearrangements that occur near and at phase transitions. Herein we apply GTRS to DPA, and DHA from -100 to 20°C. 20 Mb three-dimensional data arrays with 1°C increments and first/second derivatives allows complete assignment of solid, liquid and transition state vibrational modes, including low intensity/frequency vibrations that cannot be readily analyzed with conventional Raman. DPA and DHA show significant spectral changes with premelting (-33 and -60°C, respectively) and melting (-27 and -44°C, respectively). The CH2-(HC=CH)-CH2 moieties are not identical in the second half of the DHA and DPA structures. The DHA molecule contains major CH2 twisting (1265 cm-1) with no noticeable CH2 bending, consistent with a flat helical structure with small pitch. Further modeling of neuronal membrane phospholipids must take into account this structure for DHA, which would be configured parallel to the hydrophilic head group line.

  11. The TAOS Project: Upper Bounds on the Population of Small Kuiper Belt Objects and Tests of Models of Formation and Evolution of the Outer Solar System

    NASA Astrophysics Data System (ADS)

    Bianco, F. B.; Zhang, Z.-W.; Lehner, M. J.; Mondal, S.; King, S.-K.; Giammarco, J.; Holman, M. J.; Coehlo, N. K.; Wang, J.-H.; Alcock, C.; Axelrod, T.; Byun, Y.-I.; Chen, W. P.; Cook, K. H.; Dave, R.; de Pater, I.; Kim, D.-W.; Lee, T.; Lin, H.-C.; Lissauer, J. J.; Marshall, S. L.; Protopapas, P.; Rice, J. A.; Schwamb, M. E.; Wang, S.-Y.; Wen, C.-Y.

    2010-04-01

    We have analyzed the first 3.75 years of data from the Taiwanese American Occultation Survey (TAOS). TAOS monitors bright stars to search for occultations by Kuiper Belt objects (KBOs). This data set comprises 5 × 105 star hours of multi-telescope photometric data taken at 4 or 5 Hz. No events consistent with KBO occultations were found in this data set. We compute the number of events expected for the Kuiper Belt formation and evolution models of Pan & Sari, Kenyon & Bromley, Benavidez & Campo Bagatin, and Fraser. A comparison with the upper limits we derive from our data constrains the parameter space of these models. This is the first detailed comparison of models of the KBO size distribution with data from an occultation survey. Our results suggest that the KBO population is composed of objects with low internal strength and that planetary migration played a role in the shaping of the size distribution.

  12. THE TAOS PROJECT: UPPER BOUNDS ON THE POPULATION OF SMALL KUIPER BELT OBJECTS AND TESTS OF MODELS OF FORMATION AND EVOLUTION OF THE OUTER SOLAR SYSTEM

    SciTech Connect

    Bianco, F. B.; Zhang, Z.-W.; King, S.-K.; Wang, J.-H.; Lee, T.; Lin, H.-C.; Lehner, M. J.; Mondal, S.; Giammarco, J.; Holman, M. J.; Alcock, C.; Coehlo, N. K.; Axelrod, T.; Byun, Y.-I.; Kim, D.-W.; Chen, W. P.; Cook, K. H.; Dave, R.; De Pater, I.; Lissauer, J. J.

    2010-04-15

    We have analyzed the first 3.75 years of data from the Taiwanese American Occultation Survey (TAOS). TAOS monitors bright stars to search for occultations by Kuiper Belt objects (KBOs). This data set comprises 5 x 10{sup 5} star hours of multi-telescope photometric data taken at 4 or 5 Hz. No events consistent with KBO occultations were found in this data set. We compute the number of events expected for the Kuiper Belt formation and evolution models of Pan and Sari, Kenyon and Bromley, Benavidez and Campo Bagatin, and Fraser. A comparison with the upper limits we derive from our data constrains the parameter space of these models. This is the first detailed comparison of models of the KBO size distribution with data from an occultation survey. Our results suggest that the KBO population is composed of objects with low internal strength and that planetary migration played a role in the shaping of the size distribution.

  13. A comparison of MCNP4C electron transport with ITS 3.0 and experiment at incident energies between 100 keV and 20 MeV: influence of voxel size, substeps and energy indexing algorithm

    NASA Astrophysics Data System (ADS)

    Schaart, Dennis R.; Jansen, Jan Th M.; Zoetelief, Johannes; de Leege, Piet F. A.

    2002-05-01

    The condensed-history electron transport algorithms in the Monte Carlo code MCNP4C are derived from ITS 3.0, which is a well-validated code for coupled electron-photon simulations. This, combined with its user-friendliness and versatility, makes MCNP4C a promising code for medical physics applications. Such applications, however, require a high degree of accuracy. In this work, MCNP4C electron depth-dose distributions in water are compared with published ITS 3.0 results. The influences of voxel size, substeps and choice of electron energy indexing algorithm are investigated at incident energies between 100 keV and 20 MeV. Furthermore, previously published dose measurements for seven beta emitters are simulated. Since MCNP4C does not allow tally segmentation with the *F8 energy deposition tally, even a homogeneous phantom must be subdivided in cells to calculate the distribution of dose. The repeated interruption of the electron tracks at the cell boundaries significantly affects the electron transport. An electron track length estimator of absorbed dose is described which allows tally segmentation. In combination with the ITS electron energy indexing algorithm, this estimator appears to reproduce ITS 3.0 and experimental results well. If, however, cell boundaries are used instead of segments, or if the MCNP indexing algorithm is applied, the agreement is considerably worse.

  14. Redetermination of cyclo-tetra­kis­(μ-5,10,15,20-tetra-4-pyridyl­porphyrinato)tetra­zinc(II) dimethyl­formamide octa­solvate trihydrate at 100 K

    PubMed Central

    Seidel, Rüdiger W.; Graf, Jürgen; Goddard, Richard; Oppel, Iris M.

    2011-01-01

    The structure of the title compound, [Zn4(C40H24N8)4]·8C3H7NO·3H2O, has been redetermined at 100 K. The redetermination is of significantly higher precision and gives further insight into the disorder of pyridyl groups and solvent mol­ecules. The mol­ecules of (5,10,15,20-tetra-4-pyridyl­porphyrinato)zinc(II) (ZnTPyP) form homomolecular cyclic tetra­mers by coordination of a peripheral pyridyl group to the central Zn atom of an adjacent symmetry-related mol­ecule. The tetra­mer so formed exhibits mol­ecular S 4 symmetry and is located about a crystallographic fourfold rotoinversion axis. Severely disordered dimethyl­formamide and water mol­ecules are present in the crystal, the contributions of which were omitted from refinement. Inter­molecular C—H⋯N hydrogen bonding is observed. PMID:21522892

  15. Final report on EURAMET key comparison EURAMET.M.M-K2.6 (1345) of mass standards of 100 mg, 2 g, 20 g, 500 g (sub-multiple of the kilogram)

    NASA Astrophysics Data System (ADS)

    Zelenka, Zoltan; Davidson, Stuart; Berry, James; Vámossy, Csilla

    2015-01-01

    This project was a European regional bilateral key comparison of stainless steel standards of 100 mg, 2 g, 20 g, and 500 g as a submultiple of the kilogram carried out under the auspices of EURAMET and designated project 1345. This comparison is also a KCDB Regional Key Comparison, registered as EURAMET.M.M-K2.6. The objectives of the comparison were to check the measurement capabilities in the field of mass of BEV and provide a basis for the review of new calibration measurement capabilities (CMC). Results are linked to the key comparison reference values of CCM.M-K2. BEV (Austria) was the pilot laboratory and the provider of the transfer standards. NPL provided the link to the CCM KC and MKEH collected the measurement data and helped to ensure impartiality. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by CCM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

  16. Experimental determination of the real elements of the density matrix of H({ital n}=3) atoms produced in 20--100-keV collisions of H{sup +} on Kr

    SciTech Connect

    Seifert, N.; Gibson, N.D.; Risley, J.S.

    1995-11-01

    In continuation of our previous work, charge transfer processes occurring in protons on rare-gas-atom collisions have been investigated. Diagonal and real off-diagonal coherence elements of the density matrix for H({ital n}=3) atoms produced in 20--100-keV electron-capture collisions with Kr atoms are experimentally determined by analyzing the Balmer-{alpha} light from the decay of H atoms from the ({ital n}=3) state to the ({ital n}=2) state. The intensity and polarization of the emitted light are measured as functions of an axially symmetric electric field in the collision region. These data are fitted to a numerical model of the H atom in an electric field in order to extract density-matrix elements. The results are compared to previous studies of H{sup +} on He and Ar. The collisionally produced dipole moment of the H({ital n}=3) atom decreases for increasing atomic number of the rare-gas target atoms, which indicates that the final phase of the collision process is not essential for the formation of the dipole moment. This physical picture is further supported by our alignment data. Absolute cross sections for charge transfer to the 3{ital s}, 3{ital p}, and 3{ital d} levels are presented as well.

  17. Experimental determination of real elements of the density matrix and the dipole moment of H([ital n]=3) atoms produced from 20--100-keV H[sup +] on Ar

    SciTech Connect

    Renwick, S.P.; Martell, E.C.; Weaver, W.D.; Risley, J.S. )

    1993-10-01

    Diagonal and real off-diagonal coherence elements of the density matrix for H([ital n]=3) atoms produced in 20--100-keV electron-capture collisions of protons with Ar atoms are experimentally determined. Balmer-[alpha] light from the decay of H atoms from the ([ital n]=3) state to the ([ital n]=2) state is observed. The intensity and polarization of the light as a function of an axially symmetric electric field in the collision region are fitted to a numerical model of the H atom in an electric field in order to extract density-matrix elements. A new polarimeter, using a photoelastic modulator in conjunction with photon-counting techniques, is used in the experiment, and its efficacy is analyzed and compared to that of a rotating quarter-wave plate polarimeter previously used in similar experiments. The diagonal elements of the density matrix yield relative capture cross sections for the H(3[ital l]) angular-momentum substates, while the coherence terms are used to determine the dipole moment of the atoms produced. Results are compared to those for protons colliding with a He target and the differences are discussed.

  18. The "AS&U" 100

    ERIC Educational Resources Information Center

    Kennedy, Mike

    2006-01-01

    This article presents "American School & University's" 100 largest school districts in the U.S. The top 100 public school districts in the U.S. represent less than 1% of the more than 14,000 school districts, but in 2004-2005, they accounted for more than 20% of the nation's public school enrollment--10,795,068 students. The money spent by the 100

  19. OSSOS. II. A Sharp Transition in the Absolute Magnitude Distribution of the Kuiper Belt’s Scattering Population

    NASA Astrophysics Data System (ADS)

    Shankman, C.; Kavelaars, JJ.; Gladman, B. J.; Alexandersen, M.; Kaib, N.; Petit, J.-M.; Bannister, M. T.; Chen, Y.-T.; Gwyn, S.; Jakubik, M.; Volk, K.

    2016-02-01

    We measure the absolute magnitude, H, distribution, dN(H) ∝ 10αH, of the scattering Trans-Neptunian Objects (TNOs) as a proxy for their size-frequency distribution. We show that the H-distribution of the scattering TNOs is not consistent with a single-slope distribution, but must transition around Hg ˜ 9 to either a knee with a shallow slope or to a divot, which is a differential drop followed by second exponential distribution. Our analysis is based on a sample of 22 scattering TNOs drawn from three different TNO surveys—the Canada-France Ecliptic Plane Survey, Alexandersen et al., and the Outer Solar System Origins Survey, all of which provide well-characterized detection thresholds—combined with a cosmogonic model for the formation of the scattering TNO population. Our measured absolute magnitude distribution result is independent of the choice of cosmogonic model. Based on our analysis, we estimate that the number of scattering TNOs is (2.4-8.3) × 105 for Hr < 12. A divot H-distribution is seen in a variety of formation scenarios and may explain several puzzles in Kuiper Belt science. We find that a divot H-distribution simultaneously explains the observed scattering TNO, Neptune Trojan, Plutino, and Centaur H-distributions while simultaneously predicting a large enough scattering TNO population to act as the sole supply of the Jupiter-Family Comets.

  20. Modeling Kuiper belt objects Charon, Orcus and Salacia by means of a new equation of state for porous icy bodies

    NASA Astrophysics Data System (ADS)

    Malamud, Uri; Prialnik, Dina

    2015-01-01

    We use a one-dimensional adaptive-grid thermal evolution code to model Kuiper belt objects Charon, Orcus and Salacia and compare their measured bulk densities with those resulting from evolutionary calculations at the end of 4.6 Gyr. Our model assumes an initial homogeneous composition of mixed ice and rock, and follows the multiphase flow of water through the porous rocky medium, consequent differentiation and aqueous chemical alterations in the rock. Heating sources include long-lived radionuclides, serpentinization reactions, release of gravitational potential energy due to compaction, and crystallization of amorphous ice. The density profile is calculated by assuming hydrostatic equilibrium to be maintained through changes in composition, pressure and temperature. To this purpose, we construct an equation of state suitable for porous icy bodies with radii of a few hundred km, based on the best available empirical studies of ice and rock compaction, and on comparisons with rock porosities in Earth analog and Solar System silicates. We show that the observed bulk densities can be reproduced by assuming the same set of initial and physical parameters, including the same rock/ice mass ratio for all three bodies. We conclude that the mass of the object uniquely determines the evolution of porosity, and thus explains the observed differences in bulk density. The final structure of all three objects is differentiated, with an inner rocky core, and outer ice-enriched mantle. The degree of differentiation, too, is determined by the object's mass.

  1. Laboratory simulation of Kuiper belt object volatile ices under ionizing radiation: CO-N2 ices as a case study.

    PubMed

    Kim, Y S; Zhang, F; Kaiser, R I

    2011-09-21

    The exposure of icy Kuiper belt objects (KBOs) by ionizing radiation was simulated in this case of exposing carbon monoxide-nitrogen (CO-N(2)) ices by energetic electrons. The radiation-induced chemical processing was monitored on-line and in situ via FTIR spectroscopy and quadrupole mass spectrometry. Besides the array of carbon oxides being reproduced as in neat irradiated carbon monoxide (CO) ices studied previously, the radiation exposure at 10 K resulted in the formation of nitrogen-bearing species of isocyanato radical (OCN), linear (l-NCN), nitric oxide (NO), nitrogen dioxide (NO(2)), plus diazirinone (N(2)CO). The infrared assignments of these species were further confirmed by isotopic shifts. The temporal evolution of individual species was found to fit in first-order reaction schemes, prepping up the underlying non-equilibrium chemistry on the formation of OCN, l-NCN, and NO radicals in particular. Also unique to the binary KBO model ices and viable for the future remote detection is diazirinone (N(2)CO) at 1860 cm(-1) (2ν(5)) formed at lower radiation exposure. PMID:21687881

  2. Electron Irradiation of Kuiper Belt Surface Ices: Ternary N2-CH4-CO Mixtures as a Case Study

    NASA Astrophysics Data System (ADS)

    Kim, Y. S.; Kaiser, R. I.

    2012-10-01

    The space weathering of icy Kuiper Belt Objects was investigated in this case study by exposing methane (CH4) and carbon monoxide (CO) doped nitrogen (N2) ices at 10 K to ionizing radiation in the form of energetic electrons. Online and in situ Fourier transform infrared spectroscopy was utilized to monitor the radiation-induced chemical processing of these ices. Along with isocyanic acid (HNCO), the products could be mainly derived from those formed in irradiated binary ices of the N2-CH4 and CO-CH4 systems: nitrogen-bearing products were found in the form of hydrogen cyanide (HCN), hydrogen isocyanide (HNC), diazomethane (CH2N2), and its radical fragment (HCN2); oxygen-bearing products were of acetaldehyde (CH3CHO), formyl radical (HCO), and formaldehyde (H2CO). As in the pure ices, the methyl radical (CH3) and ethane (C2H6) were also detected, as were carbon dioxide (CO2) and the azide radical (N3). Based on the temporal evolution of the newly formed products, kinetic reaction schemes were then developed to fit the temporal profiles of the newly formed species, resulting in numerical sets of rate constants. The current study highlights important constraints on the preferential formation of isocyanic acid (HNCO) over hydrogen cyanide (HCN) and hydrogen isocyanide (HNC), thus guiding the astrobiological and chemical evolution of those distant bodies.

  3. Defect induced mobility enhancement: Gadolinium oxide (100) on Si(100)

    SciTech Connect

    Sitaputra, W.; Tsu, R.

    2012-11-26

    Growth of predominantly single crystal (100)-oriented gadolinium oxide (Gd{sub 2}O{sub 3}) on a p-type Si(100) and growth of a polycrystal with a predominant Gd{sub 2}O{sub 3}(100) crystallite on a n-type Si(100) was performed using molecular beam epitaxy. Despite a poorer crystal structure than Gd{sub 2}O{sub 3}(110), an enhancement in carrier mobility can be found only from the Gd{sub 2}O{sub 3}(100)/n-type Si(100) interface. The mobility of 1715-1780 cm{sup 2}/V {center_dot} s was observed at room temperature, for carrier concentration >10{sup 20} cm{sup -3}. This accumulation of the electrons and the mobility enhancement may arise from the two-dimensional confinement due to charge transfer across the interface similar to transfer doping.

  4. Bacterial community dissimilarity between the surface and subsurface soils equals horizontal differences over several kilometers in the western Tibetan Plateau.

    PubMed

    Chu, Haiyan; Sun, Huaibo; Tripathi, Binu M; Adams, Jonathan M; Huang, Rong; Zhang, Yangjian; Shi, Yu

    2016-05-01

    Many studies have investigated patterns in the near-surface soil microbial community over large spatial scales. However, less is known about variation in subsurface (15-30 cm of depth) microbial communities. Here we studied depth profiles of microbial communities in high-elevation soils from Tibet. The relative abundance of Acidobacteria, Chloroflexi and Alphaproteobacteria was higher in near-surface layers, while the relative abundance of Actinobacteria, Gemmatimonadetes and Betaproteobacteria was higher in the subsurface samples. The microbial community structure was distinct between the surface and subsurface soil layers, strongly correlating with variation in total carbon (TC) and carbon to nitrogen ratio (C/N). The differences in the microbial community between the layers were about the same as the horizontal differences between sites separated by many kilometers. Overall, we found that TC and C/N were the best predictors for both surface and subsurface microbial community distribution. Exploration of the relative contribution of distance and environmental variables to community composition suggests that the contemporary environment is the primary driver of microbial distribution in this region. Reflecting niche conservatism in evolution, the microbial communities in each soil site and layer tended to be more phylogenetically clustered than expected by chance, and surface soil layer samples were more likely to be clustered than subsurface samples. PMID:26914676

  5. Stratospheric Observatory for Infrared Astronomy (SOFIA) for Planetary Science and the Kuiper Belt

    NASA Astrophysics Data System (ADS)

    Reach, W. T.

    2011-10-01

    The Stratospheric Observatory for Infrared Astronomy (SOFIA [1]) is a 2.5 meter telescope on a modified 747SP aircraft. The program is managed by the National Aeronautics and Space Administration (NASA) and the Deutsches Zentrum für Luft- und Raumfahrt (DLR). Operations are supported by NASA and DLR in a partnership, with an 80/20 split per international Memorandum of Understanding.

  6. A Radio Synoptic Survey Telescope for the Next Decade and Beyond: A Square-Kilometer Array Concept

    NASA Astrophysics Data System (ADS)

    Myers, Steven T.

    2007-12-01

    The "Radio Synoptic Survey Telescope” (RSST) is a concept being developed in the US, in collaboration with the International SKA partners, as a proposal for a mid-frequency Square Kilometer Array (SKA) . This poster presents a preliminary sketch of the concept meant to encourage community feedback. The RSST would have the sensitivity to detect HI in normal galaxies out to a redshift z>1.5 (requiring a "square kilometer” of collecting area or more). It would also have high continuum polarimetric sensitivity for deep imaging and AGN studies. The core frequency coverage is proposed to be 0.4-1.4 GHz to cover HI to z=2.5 (a "Hydrogen Cosmological Evolution Telescope") with the possibility of extension of the upper frequency limit to 3 GHz or higher (a "Gravity Astrophysics Telescope"). Evaluation and costing of the various options will be an area of focus in the next few years. The RSST would operate primarily in Synoptic Survey mode, with the majority of the observing time ( 75% or more) devoted to large surveys that scan the sky on day to week cadences. There would likely be 10%-25% of time available for follow-up targeted observations and general observer projects. Examples of key surveys include (but are not exclusive to): (1) Cosmological HI Large Deep Survey; (2) Deep Continuum Survey; and a (3) Transient Monitoring Program. These surveys would be largely commensal, and would consist of sub-surveys of different regions to different depths. Science targets include "billion galaxy” cosmological redshift surveys (e.g. Baryon Acoustic Oscillations for dark energy studies), HI evolution studies, rotation measure surveys, radio supernova and GRB searches, pulsar searches and studies, and the discovery of new phenomena. Preliminary designs are based on development underway by the US-SKA consortium, the International SKA, and the general US radio astronomy community.

  7. The Planet Mercury Surface Spectroscopy and Analysis from the Kuiper Airborne Observatory and Analysis and Modeling to Determine Surface Composition

    NASA Technical Reports Server (NTRS)

    Sprague, Ann

    1997-01-01

    We had two successful flights to observe Mercury from the Kuiper Airborne Observatory (KAO) using High-efficiency Infrared Faint-Object Grating Spectrograph (HIFOGS). Flights were May 8, 1995 (eastern elongation) and July 6, 1995 (western elongation) For the observations one half of the primary mirror was covered to prevent sunlight from entering the telescope. All equipment and the airplane and its crew performed well. These flights were historical firsts for the KAO and for spectroscopy of Mercury in that it was the first time any spectroscopic observations of Mercury from above the Earth's atmosphere had been made. It was the first time the KAO had been used to @bserve an object less than 30 degrees from the Sun. Upon completion of the basic data reduction it became obvious that extensive modeling and analysis would be required to understand the data. It took three years of a graduate student's time and part time the PI to do the thermal modeling and the spectroscopic analysis. This resulted in a lengthy publication. A copy of this publication is attached and has all the data obtained in both KAO flights and the results clearly presented. Notable results are: (1) The observations found an as yet unexplained 5 micron emission enhancement that we think may be a real characteristic of Mercury's surface but could have an instrumental cause; (2) Ground-based measurements or an emission maximum at 7.7 microns were corroborated. The chemical composition of Mercury's surface must be feldspathic in order to explain spectra features found in the data obtained during the KAO flights.

  8. The effect of Rayleigh-Taylor instabilities on the thickness of undifferentiated crust on Kuiper Belt Objects

    NASA Astrophysics Data System (ADS)

    Rubin, Mark E.; Desch, Steven J.; Neveu, Marc

    2014-07-01

    Previous calculations of the internal structure and thermal evolution of Kuiper Belt Objects (KBOs) by Desch et al. (Desch, S.J., Cook, J.C., Doggett, T.C., Porter, S.B. [2009]. Icarus 202, 694-714) have predicted that KBOs should only partially differentiate, with rock and ice separating into a rocky core and icy mantle, below an undifferentiated crust of ice and rock. This crust is thermally insulating and enhances the ability of subsurface liquid to persist within KBOs. A dense rock/ice layer resting on an icy mantle is gravitationally unstable and prone to Rayleigh-Taylor (RT) instabilities, and may potentially overturn. Here we calculate the ability of RT instabilities to act in KBOs, and determine the thickness of undifferentiated crusts. We have used previously calculated growth rates of the RT instability to determine the critical viscosity of ice needed for the RT instability to operate. We calculate the viscosity of ice at the cold temperatures and long timescales relevant to KBOs. We find that crustal overturn is only possible where the temperature exceeds about 150 K, and that RT instabilities cannot act on geological timescales within about 60 km of the surfaces of a KBO like Charon. Although this crustal thickness is less than the 85 km previously calculated by Desch et al. (Desch, S.J., Cook, J.C., Doggett, T.C., Porter, S.B. [2009]. Icarus 202, 694-714), it is still significant, representing ≈25% of the mass of the KBO. We conclude that while RT instabilities may act in KBOs, they do not completely overturn their crusts. We calculate that Saturn’s moon Rhea should only partially differentiate, resulting in a moment of inertia C/MR2≈0.38.

  9. The Effect Off Rayleigh-Taylor Instabilities On The Thickness Of Undifferentiated Crust On Kuiper Belt Objects Like Charon

    NASA Astrophysics Data System (ADS)

    Rubin, Mark

    In this thesis I model the thermal and structural evolution of Kuiper Belt Objects (KBOs) and explore their ability to retain undifferentiated crusts of rock and ice over geologic timescales. Previous calculations by Desch et al. (2009) predicted that initially homogenous KBOs comparable in size to Charon (R ~ 600 km) have surfaces too cold to permit the separation of rock and ice, and should always retain thick (≈ 85 km) crusts, despite the partial differentiation of rock and ice inside the body. The retention of a thermally insulating, undifferentiated crust is favorable to the maintenance of subsurface liquid and potentially cryovolcanism on the KBO surface. A potential objection to these models is that the dense crust of rock and ice overlying an ice mantle represents a gravitationally unstable configuration that should overturn by Rayleigh-Taylor (RT) instabilities. I have calculated the growth rate of RT instabilities at the ice-crust interface, including the effect of rock on the viscosity. I have identified a critical ice viscosity for the instability to grow significantly over the age of the solar system. I have calculated the viscosity as a function of temperature for conditions relevant to marginal instability. I find that RT instabilities on a Charon-sized KBO require temperatures T > 143 K. Including this effect in thermal evolution models of KBOs, I find that the undifferentiated crust on KBOs is thinner than previously calculated, only ≈ 50 km. While thinner, this crustal thickness is still significant, representing ≈ 25% of the KBO mass, and helps to maintain subsurface liquid throughout most of the KBO's history.

  10. International Workshop on First Decadal Review of the Edgeworth-Kuiper Belt: Toward new Frontiers

    NASA Astrophysics Data System (ADS)

    Hainaut, O.

    2003-06-01

    On March 11 to 14, 2003, an international conference on the Minor Bodies in the Outer Solar System was held in Antofagasta, Chile. The conference, which was organized by ESO and Universidad Catolica del Norte (UCN) of Antofagasta, gathered about 70 participants from 20 countries. Originally, it was supposed to take place on the UCN campus. However, a student strike forced us to relocate at the last minute to the Carrera Club Hotel. Thanks to the efforts of A. Lagarini, the conference secretary (and ESO/Chile Science secretary) and to the Hotel staff, this did not cause any disruption. The traditional group photo (opposite) was shot in front of the Geological Museum of UCN. This short summary highlights some of the results presented at this conference; the proceedings, which are currently being edited, will be published as a special issue of “Earth, Moon and Planets.”

  11. Pushing the limits of spatial resolution with the Kuiper Airborne observatory

    NASA Technical Reports Server (NTRS)

    Lester, Daniel

    1994-01-01

    The study of astronomical objects at high spatial resolution in the far-IR is one of the most serious limitations to our work at these wavelengths, which carry information about the luminosity of dusty and obscured sources. At IR wavelengths shorter than 30 microns, ground based telescopes with large apertures at superb sites achieve diffraction-limited performance close to the seeing limit in the optical. At millimeter wavelengths, ground based interferometers achieve resolution that is close to this. The inaccessibility of the far-IR from the ground makes it difficult, however, to achieve complementary resolution in the far-IR. The 1983 IRAS survey, while extraordinarily sensitive, provides us with a sky map at a spatial resolution that is limited by detector size on a spatial scale that is far larger than that available in other wavelengths on the ground. The survey resolution is of order 4 min in the 100 micron bandpass, and 2 min at 60 microns (IRAS Explanatory Supplement, 1988). Information on a scale of 1' is available on some sources from the CPC. Deconvolution and image resolution using this database is one of the subjects of this workshop.

  12. La estructura dinámica del cinturón de Kuiper interior y la formación de Urano y Neptuno

    NASA Astrophysics Data System (ADS)

    Melita, M. D.; Brunini, A.

    De acuerdo a los más recientes estudios sobre la formación de Urano y Neptuno, éstos podrían haber sufrido una importante migración radial hacia el exterior, debido al intercambio de momento angular con los planetesimales presentes en esa región durante las últimas etapas de la formación del Sistema Solar. Esta migración radial habría tenido importantes consecuencias sobre la presente estructura dinámica del cinturón cometario de Kuiper. Tal como lo reflejan las observaciones, la mayoría de los cuerpos observados en el cinturón de Kuiper se encuentran en resonancia de movimientos medios exteriores con Neptuno, hecho que también se refleja en la presente órbita de Plutón. En el presente trabajo se estudia tanto numérica como analíticamente la influencia de la variación de las masas de Urano y Neptuno durante el proceso de migración sobre las probabilidades de captura en algunas de las resonancias exteriores de Neptuno. Se estudia también la influencia de encuentros gravitacionales mutuos sobre la estabilidad de las órbitas resonantes. Este estudio ofrece argumentos de plausibilidad para explicar por qué ninguno de los objetos descubiertos en el cinturón de Kuiper se encontraría en la resonancia 2:1.

  13. Signal Coherence and Improved Bandwidth in Kilometer-Scale Water-Pipe Tilt-Meters for Monitoring Slow Earthquakes

    NASA Astrophysics Data System (ADS)

    Bilham, R.; Suszek, N.; Flake, R.; Szeliga, W.; Melbourne, T.

    2005-12-01

    Slow earthquakes have been detected by GPS networks in numerous subduction zones but signals are frequently close to detection levels. Although strain-meters and tilt-meters possess a thousandfold higher resolution (~ 1 nstrain & 1 nrad), noise levels in these instruments tend to be site specific and it is sometimes considered necessary to instal clusters to distinguish tectonic signal from local noise. This approach to strain measurement can more than double the cost of initial installation. We report here first results from a half-km-long water pipe tiltmeter in which a test for signal coherence is an inherent product of the geometry of the instrument. An appealing feature of water-pipe tiltmeters is that they cost 25% less than a borehole strain-meter, assume long good long term stability within days of installation, and unlike the decade-longevity of borehole systems, have an indefinite life span. In a Michelson tilt-meter, tilt of the earth's surface is manifest as a rise in water level at one end of the pipe and an equal and opposite reduction in water level at the other. In newly installed tiltmeters in the Cascadia region we have introduced a central transducer that effectively provides two 250-m-long independent measures of tilt in each 500 m long pipe, and hence a measure of signal coherence for little extra cost. Data from each sensor are telemetered via radio modem to a remote computer at rates of 1-6 samples/minute. Initial results from four 500 m long water pipes installed in the Cascadia region, reveal that a secular drift level of better than 0.1 microradian/yr is established within a week of installation and that the two half-tiltmeters track each other closely at all periods. Noise levels are frequency dependent and vary form 0.2 nrad at hourly periods to 100 nrad at yearly periods. Atmospheric and aperiodic ocean loading appears to be the largest souce of noise at periods of several days to weeks in the bandwidth where slow earthquakes are

  14. 21 CFR 100.100 - Misleading containers.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION GENERAL Misbranding for Reasons Other Than Labeling § 100.100 Misleading... is inherent to the nature of the food and is clearly communicated to consumers; (5) The fact that...

  15. Latest Results from and Plans for the New Horizons Pluto-Kuiper Belt Mission

    NASA Astrophysics Data System (ADS)

    Weaver, Harold; Stern, Alan

    2016-07-01

    spacecraft remains healthy and was targeted toward the flyby of a small (~30-40 km) KBO in late-2015, enabling the study of an object (2014 MU69) in a completely different dynamical class (cold classical) than Pluto, if NASA approves an Extended Mission phase. In addition to the flyby of 2014 MU69 on 2019-Jan-01, the proposed Extended Mission would also include observations of more than 20 other KBOs at resolutions and geometries not feasible from Earth, and studies of the heliospheric plasma, neutral H and He, and the dust environment out to 50 AU from the Sun.

  16. THE CANADA-FRANCE ECLIPTIC PLANE SURVEY-FULL DATA RELEASE: THE ORBITAL STRUCTURE OF THE KUIPER BELT

    SciTech Connect

    Petit, J.-M.; Rousselot, P.; Mousis, O.; Kavelaars, J. J.; Gladman, B. J.; Jones, R. L.; Van Laerhoven, C.; Parker, J. Wm.; Bieryla, A.; Nicholson, P.; Mars, G.; Marsden, B.; Ashby, M. L. N.; Taylor, M.; Bernabeu, G.; Benavidez, P.; Campo Bagatin, A.

    2011-10-15

    % confidence). We show how the CFEPS Survey Simulator can be used to compare a cosmogonic model for the orbital element distribution to the real Kuiper Belt.

  17. Comparison of 4-kilometer and 800-meter transient PRISM climate datasets and their influence on hydrologic modeling

    NASA Astrophysics Data System (ADS)

    Stern, M. A.; Flint, A. L.; Curtis, J. A.; Flint, L. E.

    2011-12-01

    Historical climate maps in the form of gridded monthly precipitation and maximum and minimum air temperature are available at a 4-kilometer (km) and 800-meter (m) resolution from the Parameter-elevation Regressions on Independent Slopes Model (PRISM) Climate Group at Oregon State University. The PRISM climate maps include weighting functions for distance, elevation, topographic facet, atmospheric layer, orographic effectiveness, and coastal proximity. Many researchers rely on these datasets as inputs to computer models and statistical analyses that are used for making land and resource management decisions. We compared the 1970-2000 precipitation, maximum air temperature (Tmax), and minimum air temperature (Tmin) from the two datasets nationally and for California. At the national scale we averaged climate parameters by state and found variable results indicating differences between the two data sets. When comparing average precipitation data by state, the 4-km and 800-m data are strikingly similar with a mean difference of less than 0.1%. Comparisons of Tmax showed a mean difference of less than 1% except for two states, Wyoming and Idaho. Comparison of Tmin indicates greater than 1% difference with the greatest differences in California and Arkansas. For California we used the 35 Jepson Eco-region districts to provide a more detailed analysis of within-state variation. We found that the most significant differences between the datasets are in the Warner Mountains, Channel Islands, and southern Sierra Nevada Foothills. To assess accuracy differences between the two datasets, we compared the 4-km and the 800-m datasets to weather station data from the U.S. Historical Climatology Network (HCN). The 4-km and 800-m datasets were used as the climate input for a monthly water-balance model (Basin Characterization Model; BCM) of California to evaluate differences in simulated hydrologic output (recharge, runoff, and snowmelt). The 4-km BCM simulated recharge and runoff

  18. THE HUBBLE WIDE FIELD CAMERA 3 TEST OF SURFACES IN THE OUTER SOLAR SYSTEM: THE COMPOSITIONAL CLASSES OF THE KUIPER BELT

    SciTech Connect

    Fraser, Wesley C.; Brown, Michael E.

    2012-04-10

    We present the first results of the Hubble Wide Field Camera 3 Test of Surfaces in the Outer Solar System. The purpose of this survey was to measure the surface properties of a large number of Kuiper Belt objects and attempt to infer compositional and dynamical correlations. We find that the Centaurs and the low-perihelion scattered disk and resonant objects exhibit virtually identical bifurcated optical color distributions and make up two well-defined groups of objects. Both groups have highly correlated optical and NIR colors that are well described by a pair of two-component mixture models that have different red components but share a common neutral component. The small, H{sub 606} {approx}> 5.6 high-perihelion excited objects are entirely consistent with being drawn from the two branches of the mixing model, suggesting that the color bifurcation of the Centaurs is apparent in all small excited objects. On the other hand, objects larger than H{sub 606} {approx} 5.6 are not consistent with the mixing model, suggesting some evolutionary process avoided by the smaller objects. The existence of a bifurcation amongst all excited populations argues that the two separate classes of object existed in the primordial disk before the excited Kuiper Belt was populated. The cold classical objects exhibit a different type of surface that has colors that are consistent with being drawn from the red branch of the mixing model, but with much higher albedos.

  19. The 100 People Project

    ERIC Educational Resources Information Center

    McLeod, Keri

    2007-01-01

    This article describes the 100 People Project and how the author integrates the project in her class. The 100 People Project is a nonprofit organization based in New York City. The organization poses the question: If there were only 100 people in the world, what would the world look like? Through the project, students were taught about ethics in…

  20. Molecular Shocks Associated with Massive Young Stars: CO Line Images with a New Far-Infrared Spectroscopic Camera on the Kuiper Airborne Observatory

    NASA Technical Reports Server (NTRS)

    Watson, Dan M.

    1997-01-01

    Under the terms of our contract with NASA Ames Research Center, the University of Rochester (UR) offers the following final technical report on grant NAG 2-958, Molecular shocks associated with massive young stars: CO line images with a new far-infrared spectroscopic camera, given for implementation of the UR Far-Infrared Spectroscopic Camera (FISC) on the Kuiper Airborne Observatory (KAO), and use of this camera for observations of star-formation regions 1. Two KAO flights in FY 1995, the final year of KAO operations, were awarded to this program, conditional upon a technical readiness confirmation which was given in January 1995. The funding period covered in this report is 1 October 1994 - 30 September 1996. The project was supported with $30,000, and no funds remained at the conclusion of the project.

  1. The First High-phase Observations of a KBO: New Horizons Imaging of (15810) 1994 JR1 from the Kuiper Belt

    NASA Astrophysics Data System (ADS)

    Porter, Simon B.; Spencer, John R.; Benecchi, Susan; Verbiscer, Anne J.; Zangari, Amanda M.; Weaver, H. A.; Lauer, Tod R.; Parker, Alex H.; Buie, Marc W.; Cheng, Andrew F.; Young, Leslie A.; Olkin, Cathy B.; Ennico, Kimberly; Stern, S. Alan; the New Horizons Science Team

    2016-09-01

    NASA’s New Horizons spacecraft observed (15810) 1994 JR1, a 3:2 resonant Kuiper belt object (KBO), using the LOng Range Reconnaissance Imager (LORRI) on 2015 November 2 from a distance of 1.85 au and again on 2016 April 7 from a distance of 0.71 au. These were the first close observations of any KBO other than Pluto. Combining ground-based and Hubble Space Telescope (HST) observations at small phase angles and the LORRI observations at higher phase angles, we produced the first disk-integrated solar phase curve of a typical KBO from α = 0.°6–58°. Observations at these geometries, attainable only from a spacecraft in the outer solar system, constrain surface properties such as macroscopic roughness and the single particle phase function. 1994 JR1 has a rough surface with a 37° ± 5° mean topographic slope angle and has a relatively rapid rotation period of 5.47 ± 0.33 hr. 1994 JR1 is currently 2.7 au from Pluto; our astrometric points enable high-precision orbit determination and integrations that show that it comes this close to Pluto every 2.4 million years (104 heliocentric orbits), causing Pluto to perturb 1994 JR1. During the November spacecraft observation, the KBO was simultaneously observed using HST in two colors, confirming its very red spectral slope. These observations have laid the groundwork for numerous potential future distant KBO observations in the New Horizons–Kuiper belt extended mission.

  2. A test of water vapor radiometer-based troposphere calibration using VLBI observations on a 21-kilometer baseline

    NASA Technical Reports Server (NTRS)

    Linfield, R. P.; Teitelbaum, L. P.; Skjerve, L. J.; Keihm, S. J.; Walter, S. J.; Mahoney, M. J.; Treuhaft, R. N.

    1995-01-01

    Simultaneous very long baseline interferometry (VLBI) and water vapor radiometer (WVR) measurements on a 21 km baseline showed that calibration by WVRs removed a significant fraction of the effect of tropospheric delay fluctuations for these experiments. From comparison of the residual delay variations within scans and between scans, the total tropospheric contribution t the delay residuals for each of the three 5 to 20 hour sessions was estimated as 1, 17, and 10%, with the first value being uncertain. The observed improvement in rms residual delay from WVR calibration during these three sessions was 4, 16, and 2%, respectively. The improvement is consistent with the estimated 2 to 3 mm path delay precision of current WVRs. The VLBI measurements, of natural radio sources, were conducted in April and May 1993 at Goldstone, California. Dual-frequency (2.3 and 8.4 GHz) observations were employed to remove the effects of charged particles from the data. Measurements with co-pointed WVRs, located within 50 m of the axis of each antenna, were performed to test the ability of the WVRs to calibrate line-of-sight path delays. Factors that made WVR performance assessment difficult included (1) the fact that the level of tropospheric fluctuations was smaller than is typical for Goldstone during these experiments and (2) VLBI delay variations on longer time scales (i.e., over multiple scans) contained uncalibrated instrumental effects (probably a result of slow temperature variations in the VLBI hardware) that were larger than the tropospheric effects.

  3. 11 CFR 100.91 - Recounts.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... a Federal election, is not a contribution except that the prohibitions of 11 CFR 110.20 and part 114... Contributions § 100.91 Recounts. A gift, subscription, loan, advance, or deposit of money or anything of...

  4. 100 Weekly Sky Maps

    NASA Technical Reports Server (NTRS)

    2002-01-01

    100 Aum Weekly Sky Maps for mission weeks 4 to 44, and the 100 Aum Annual Average Map. Shows sky coverage each week of the DIRBE mission over the period during which the COBE cryogen supply lasted. As the Earth, with COBE in orbit, revolved around the Sun, DIRBE viewed the sky from an ever-changing vantage point in the solar system, enabling light reflected and emitted by the interplanetary dust cloud to be modeled.

  5. Kilometer-scale slopes on Mars and their correlation with geologic units: Initial results from Mars Orbiter Laser Altimeter (MOLA) data

    NASA Astrophysics Data System (ADS)

    Kreslavsky, M. A.; Head, J. W.

    1999-09-01

    Martian surface slopes were calculated at baselines from 0.4 to 25 km using profiles obtained by the Mars Orbiter Laser Altimeter (MOLA) instrument during the aerobraking phase of the Mars Global Surveyor mission. Median slope is proposed as a characteristic measurement of the typical surface roughness at each corresponding scale. Median slope is favored over RMS slope because it is not influenced by the small number of higher slopes at the upper end of the slope-frequency distribution tail. Median slope complements interquartile scale roughness characterization in that it is more sensitive to smaller baseline slopes. A map of the median slope of the northern hemisphere is presented. Median slopes and their scale dependences are used to characterize typical kilometer-scale roughness for a set of geologic units mapped in the northern hemisphere. This analysis demonstrates that many individual units and groups of units are characterized by distinctive surface slopes and that these characteristics are sufficiently different that they hold promise for use in the definition and characterization of units. Characterization of the slope properties of geologic units provides information useful in the interpretation of their origin and evolution. For example, the generally smooth topography of the diverse Vastitas Borealis Formation subunits is dominated by about 3 km, 0.3° steep features almost indistinguishable in Viking images. The roughness characteristics of this unit differ from those of other geologic units on Mars and suggest some distinctive process(es) of formation and/or modification of kilometer-scale topography common for all subunits. The similarity of roughness characteristics of the several highland plateau units suggests that kilometer-scale topography was largely inherited from the period of heavy bombardment. The northern polar cap and layered terrains are largely very smooth at small scale. The long, steep-sloped tails of the slope

  6. Interfacial Tension-Driven Differentiation-(ITDD) may result in a low-density central region inside kilometer-sized bodies

    NASA Astrophysics Data System (ADS)

    Arias, Francisco J.

    2016-03-01

    Interfacial Tension-Driven Differentiation, (ITDD), and its possible significance with regards to the interior structures of kilometer-sized bodies is discussed. Using a simple physical and geometrical model, an analytical expression for the conditions in which ITDD can occur is derived. It is shown that ITDD coupled with internal convection can lead to a counterintuitive result: that central regions may be less dense than outer regions in km-sized, initially melted bodies. ITDD offers an alternative explanation to the formation of microporosity inside of small bodies, (e.g. Churyumov-Gerasimenko-like objects), as well as macroporosity, which is suggested to occur in the interior of Mars' larger satellite Phobos, without recourse to rubble-pile models. Depending on the development of the velocity boundary layer at the solidification front, ITDD allows not just the possibility of central porosity, but also more complex scenarios, such as the formation of internal porosity rings.

  7. AFR-100 safety analyses

    SciTech Connect

    Sumner, T.; Moisseytsev, A.; Wei, T. Y. C.

    2012-07-01

    The Advanced Fast Reactor-100 (AFR-100) is Argonne National Laboratory's 250 MWth metal-fueled modular sodium-cooled pool-type fast reactor concept. [1] A series of accident sequences that focused on the AFR-100's ability to provide protection against reactor damage during low probability accident sequences resulting from multiple equipment failures were examined. Protected and Unprotected Loss of Flow (PLOF and ULOF) and Unprotected Transient Over-Power (UTOP) accidents were simulated using the SAS4A/SASSYS-1 safety analysis code. The large heat capacity of the sodium in the pool-type reactor allows the AFR-100 to absorb large amounts of energy during a PLOF with relatively small temperature increases throughout the system. During a ULOF with a 25-second flow halving time, coolant and cladding temperatures peak around 720 deg. C within the first minute before reactivity feedback effects decrease power to match the flow. Core radial expansion and fuel Doppler provide the necessary feedback during the UTOP to bring the system back to critical before system temperatures exceed allowable limits. Simulation results indicate that adequate ULOF safety margins exist for the AFR-100 design with flow halving times of twenty-five seconds. Significant safety margins are maintained for PLOF accidents as well as UTOP accidents if a rod stop is used. (authors)

  8. 20 CFR 1001.100 - Purpose and scope of subpart.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ....S.C. 2001-2012, chapters 41 and 42, which require the Secretary of Labor to provide eligible... Vietnam era to job openings listed by Federal contractors pursuant to 38 U.S.C. 2012(a), and (3) Reporting of services provided to eligible veterans and eligible persons pursuant to 38 U.S.C. 2007(c) and...

  9. 20 CFR 1001.100 - Purpose and scope of subpart.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ....S.C. 2001-2012, chapters 41 and 42, which require the Secretary of Labor to provide eligible... Vietnam era to job openings listed by Federal contractors pursuant to 38 U.S.C. 2012(a), and (3) Reporting of services provided to eligible veterans and eligible persons pursuant to 38 U.S.C. 2007(c) and...

  10. 20 CFR 1001.100 - Purpose and scope of subpart.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ....S.C. 2001-2012, chapters 41 and 42, which require the Secretary of Labor to provide eligible... Vietnam era to job openings listed by Federal contractors pursuant to 38 U.S.C. 2012(a), and (3) Reporting of services provided to eligible veterans and eligible persons pursuant to 38 U.S.C. 2007(c) and...

  11. 50 CFR 100.20 - Request for reconsideration.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... file a request for reconsideration with the Board. (c) To file a request for reconsideration, you must notify the Board in writing within sixty (60) days of the effective date or date of publication of the... provide the Board with sufficient narrative evidence and argument to show why the action by the...

  12. 50 CFR 100.20 - Request for reconsideration.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... file a request for reconsideration with the Board. (c) To file a request for reconsideration, you must notify the Board in writing within sixty (60) days of the effective date or date of publication of the... provide the Board with sufficient narrative evidence and argument to show why the action by the...

  13. 50 CFR 100.20 - Request for reconsideration.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... file a request for reconsideration with the Board. (c) To file a request for reconsideration, you must notify the Board in writing within sixty (60) days of the effective date or date of publication of the... provide the Board with sufficient narrative evidence and argument to show why the action by the...

  14. 50 CFR 100.20 - Request for reconsideration.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... file a request for reconsideration with the Board. (c) To file a request for reconsideration, you must notify the Board in writing within sixty (60) days of the effective date or date of publication of the... provide the Board with sufficient narrative evidence and argument to show why the action by the...

  15. 50 CFR 100.20 - Request for reconsideration.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... file a request for reconsideration with the Board. (c) To file a request for reconsideration, you must notify the Board in writing within sixty (60) days of the effective date or date of publication of the... provide the Board with sufficient narrative evidence and argument to show why the action by the...

  16. 20 healthy snacks with 100 calories or less

    MedlinePlus

    ... you full. Healthy snacks are: Whole grain Low-calorie Low-salt Low-sugar Fresh foods, rather than ... damage), and other disease-fighting nutrients. Choosing low-calorie snacks can help you or your child maintain ...

  17. Which 100-kyr Cycle?

    NASA Astrophysics Data System (ADS)

    Berger, A.; Loutre, M. F.; Mélice, J. L.

    The origin of all the fundamental frequencies characterising the long term variations of the astronomical parameters has been identified. This allows to discuss their inter- relationship and possible changes in times. Different sources for the so-called 100-kyr cycle have been found in the astronomical parameters and in the insolation itself. The most popular 100-kyr cycle is certainly the eccentricity one. Actually, the periods of the most important spectral components of e used in Berger (1978) are 412 885, 14 945, 123 297, 99 590 and 131 248 yr. Instability of the resulting average 100-kyr cy- cle has been shown related to the ~ 400-kyr cycle. The derivative of eccentricity is definitely showing a spectrum dominated by the 100-kyr cycle with the same spectral components as e itself. The inclination of the Earth orbital plane on the ecliptic does not display any 100-kyr cycle, but it is not the case for its inclination on the reference plane for which cycles of 98 046 and 107 478 years appear. Finally the frequency modulation of obliquity is characterised by cycles 171 kyr and 97 kyr long. For inso- lation, it is known that there is only a very weak signal around 100-kyr coming from e itself. However, if we consider the seasonal cycle at the equator, its amplitude varies with cycles of 400 kyr, 100 kyr, 41 kyr, 10 kyr and 5 kyr, all related to e. Although all these cycles are close to the 100 kyr cycle found in geological data, the origin of this kind of cycle can be best identified by comparing the proxy record to the re- sponse of the climate system to the astronomical forcing. This forcing signal which contains, in one way or another, the astronomical characteristics mentioned above is, at least, partly distorted and transformed, a modification which can only be estimated through climate models. Such a climate model has been developed in the early 80Ss in Louvain-la-Neuve and used since to simulate the last and next glacial-interglacial cycles.

  18. Spitzer Space Telescope Observations of G Dwarfs in the Pleiades: Circumstellar Debris Disks at 100 Myr Age

    NASA Astrophysics Data System (ADS)

    Stauffer, John R.; Rebull, Luisa M.; Carpenter, John; Hillenbrand, Lynne; Backman, Dana; Meyer, Michael; Kim, Jinyoung Serena; Silverstone, Murray; Young, Erick; Hines, Dean C.; Soderblom, David R.; Mamajek, Eric; Morris, Patrick; Bouwman, Jeroen; Strom, Stephen E.

    2005-10-01

    Fluxes and upper limits in the wavelength range from 3.6 to 70 μm from the Spitzer Space Telescope are provided for 20 solar-mass Pleiades members. One of these stars shows a probable mid-IR excess, and two others have possible excesses, presumably due to circumstellar debris disks. For the star with the largest, most secure excess flux at MIPS (Multiband Imaging Photometer for Spitzer) wavelengths, HII 1101, we derive log(Ldust/L*)~-3.8 and an estimated debris disk mass of 4.2×10-5 M♁ for an assumed uniform dust grain size of 10 μm. If the stars with detected excesses are interpreted as stars with relatively recent, large collisional events producing a transient excess of small dust particles, the frequency of such disk transients is ~10% for our ~100 Myr, Pleiades G dwarf sample. For the stars without detected 24-70 μm excesses, the upper limits to their fluxes correspond to approximate 3 σ upper limits to their disk masses of 6×10-6 M♁ using the MIPS 24 μm upper limit or 2×10-4 M♁ using the MIPS 70 μm limit. These upper limit disk masses (for ``warm'' and ``cold'' dust, respectively) are roughly consistent with, but somewhat lower than, predictions of a heuristic model for the evolution of an ``average'' solar-mass star's debris disk based on extrapolation backward in time from current properties of the Sun's Kuiper Belt. This work is based (in part) on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under NASA contract 1407. This publication makes use of data products from the Two Micron All Sky Survey, which is a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center, California Institute of Technology, funded by the National Aeronautics and Space Administration and the National Science Foundation.

  19. Tuskegee: 100 Years Later.

    ERIC Educational Resources Information Center

    Higgins, Renelda

    1981-01-01

    Reviews the history and accomplishments of Tuskegee Institute over the past 100 years. Highlights the role played by Booker T. Washington, and W. E. B. DuBois; discusses the career of the school's retiring president, Luther Foster. Provides information on the new president, Dr. Benjamin Payton, and discusses future directions for the college. (APM)

  20. 100 Winning Curriculum Ideas.

    ERIC Educational Resources Information Center

    National School Boards Association, Alexandria, VA.

    The editors of "The American School Board Journal" and "The Executive Educator" magazines recently invited school leaders from across North America to send in curriculum ideas that work. From among the 1,026 entries that were submitted, a panel of judges selected 100, which are published in this special report. Criteria for selection included (1)…