scholarly journals ONGOING FOLLOW-UP NEA OBSERVATIONS IN UKRAINE AND CHINA USING RDS CCD TECHNIQUE

2021 ◽  
Vol 34 ◽  
pp. 110-113
Author(s):  
A.V. Pomazan ◽  
N.V. Maigurova ◽  
A.V. Shulga ◽  
Z.-H. Tang
Keyword(s):  
Moving Objects ◽  
Local Level ◽  
Short Interval ◽  
Time Moment ◽  
Sharp Decrease ◽  
Close Approach ◽  
Apparent Magnitude ◽  
Minimal Distance ◽  
The Earth ◽  
Drift Scan

The current state of near-Earth asteroids (NEAs) observations shows an annual increase in the number of newly discovered objects However, the frequency distribution of NEAs by size shows a sharp decrease in the number of objects with size less than 300 m, which contradicts the results of theoretical modeling of the NEA population. Considering definition of potentially hazardous asteroids (PHA), only objects with diameters more than 140 m could pose catastrophic consequences to the Earth and mankind in general. But in the same time, impacts of smaller size objects could lead to significant consequences on local level and their large predicted number increases this probability. Due to their small size which results in faint apparent magnitude, such NEAs are discovered in a short interval of their close approach (CA) to the Earth, when their apparent magnitude are tending to be as bright as possible for a given size. This is not only facilitates the detection of such new objects but also increases their observability by small ground-based telescopes. However, apparent rate of motion during this time might exceed 10 deg d −1 making the observations challenging. The used Rotating-drift-scan CCD (RDS CCD) technique allows to get images of fast-moving objects as a point, that in turn to determine the coordinates of their image centers with sufficient astrometric precision. Obtained in current research project positions show errors in the range ± (0.2″ − 0.3″) in both coordinates with comparison both to JPL's HORIZONS 1 system and NEODyS-2 2 service. The part of observations was obtained around time moment of minimal distance to the Earth during current CA for newly discovered NEAs. Such observations are important to extend observed orbital arc for reliable improvement of their orbit determinations and reducing orbital uncertainty, so it will be possible to recover them in next apparitions.

Uncertainty Estimation for Magnetic Maps

2021 ◽  
Author(s):  
Richard Saltus ◽  
Arnaud Chulliat ◽  
Brian Meyer ◽  
Christopher Amante
Keyword(s):  
Local Level ◽  
Uncertainty Estimation ◽  
Measured Data ◽  
Magnetic Minerals ◽  
Geochemical Environment ◽  
The Earth ◽  
Uncertainty Estimates ◽  
Wide Range ◽  
Machine Learning Applications ◽  
Map Data

<p>Magnetic maps depict spatial variations in the Earth’s magnetic field.  These variations occur at a wide range of scales and are produced via a variety of physical processes related to factors including structure and evolution of the Earth’s core field and the geologic distribution of magnetic minerals in the lithosphere.  Mankind has produced magnetic maps for 100’s of years with increasing fidelity and accuracy and there is a general understanding (particularly among the geophysicists who produce and use these maps) of the approximate level of resolution and accuracy of these maps.  However, few magnetic maps, or the digital grids that typically underpin these maps, have been produced with accompanying uncertainty quantification.  When uncertainty is addressed, it is typically a statistical representation at the grid or survey level (e.g., +- 10 nT overall uncertainty based on line crossings for a modern airborne survey) and not at the cell by cell local level.</p><p>As magnetic map data are increasingly used in complex inversions and in combination with other data or constraints (including in machine learning applications), it is increasingly important to have a handle on the uncertainties in these data.  An example of an application with need for detailed uncertainty estimation is the use of magnetic map information for alternative navigation.  In this application data from an onboard magnetometer is compared with previously mapped (or modeled) magnetic variations.  The uncertainty of this previously mapped information has immediate implications for the potential accuracy of navigation.</p><p>We are exploring the factors contributing to magnetic map uncertainty and producing uncertainty estimates for testing using new data collection in previously mapped (or modeled) map areas.  These factors include (but are likely not limited to) vintage and type of measured data, spatial distribution of measured data, expectation of magnetic variability (e.g., geologic or geochemical environment), statistics of redundant measurement, and spatial scale/resolution of the magnetic map or model.  The purpose of this talk is to discuss the overall issue and our initial results and solicit feedback and ideas from the interpretation community.</p>

The influence of climate change on waterborne disease and Legionella: a review

2018 ◽  
Vol 138 (5) ◽  
pp. 282-286 ◽  
Author(s):  
JT Walker
Keyword(s):  
Climate Change ◽  
Disease Transmission ◽  
Local Level ◽  
Extreme Weather ◽  
Extreme Weather Events ◽  
Waterborne Diseases ◽  
Sea Levels ◽  
The Earth ◽  
Weather Events ◽  
Rising Sea Levels

Climate change is predicted to have a major impact on people’s lives with the recent extreme weather events and varying abnormal temperature profiles across the world raising concerns. The impacts of global warming are already being observed, from rising sea levels and melting snow and ice to changing weather patterns. Scientists state unequivocally that these trends cannot be explained by natural variability in climate alone. Human activities, especially the burning of fossil fuels, have warmed the earth by dramatically increasing concentrations of heat-trapping gases in the atmosphere; as these concentrations increase, the more the earth will warm. Climate change and related extreme weather events are being exacerbated sooner than has previously been considered and are already adversely affecting ecosystems and human health by increasing the burden and type of disease at a local level. Changes to the marine environment and freshwater supplies already affect significant parts of the world’s population and warmer temperatures, especially in more temperate regions, may see an increased spread and transmission of diseases usually associated with warmer climes including, for example, cholera and malaria; these impacts are likely to become more severe in a greater number of countries. This review discusses the impacts of climate change including changes in infectious disease transmission, patterns of waterborne diseases and the likely consequences of climate change due to warmer water, drought, higher rainfall, rising sea levels and flooding.

Effects of the rotation of a spacecraft in an atmospheric close approach with the Earth

2020 ◽  
Vol 229 (8) ◽  
pp. 1517-1526
Author(s):  
Jhonathan O. Murcia Piñeros ◽  
Vivian Martins Gomes ◽  
Walter Abrahão dos Santos ◽  
Justyna Golebiewska
Keyword(s):  
Close Approach ◽  
The Earth

Satellite Cluster Close Approaches Determination for Collision Avoidance

2018 ◽  
Vol 10 (1) ◽  
Author(s):  
S. Charulatha ◽  
Raju Garudachar
Keyword(s):  
Collision Avoidance ◽  
Close Approach ◽  
Simulation Tool ◽  
The Earth ◽  
Space Objects ◽  
Minimum Separation

As the number of space objects in orbit about the Earth increases, it is extremely important to determine the close approaches between them. In this paper the close approaches is determined for the satellite cluster using a simulation tool STK for the following (i) satellites of interest within a cluster (ii) a satellites of interest in a cluster and the space objects as listed in the space catalog and the close approach reports are analyzed. The results have indicated that the details of intruder satellites and the duration of close approaches and their minimum separation distances or the relative distances.

scholarly journals A Close Approach to the Earth

Nature ◽  
1936 ◽  
Vol 137 (3470) ◽  
pp. 732-733
Keyword(s):  
Close Approach ◽  
The Earth

scholarly journals The Study of the Asymmetric Multiple Encounters Problem and Its Application to Obtain Jupiter Gravity Assisted Maneuvers

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Denilson Paulo Souza dos Santos ◽  
Antônio Fernando Bertachini de Almeida Prado ◽  
Evandro Marconi Rocco
Keyword(s):  
Interplanetary Space ◽  
Space Vehicle ◽  
Close Approach ◽  
Velocity Variation ◽  
Return Trip ◽  
Eccentric Anomaly ◽  
The Earth ◽  
Energy Variation ◽  
Arrival Angles

The Multiple Encounters Problem is described in the literature as the problem of finding trajectories for a spacecraft that leaves from a mother planet, describes a trajectory in the interplanetary space, and then goes back to the mother planet. The present paper extends the literature and the departure and arrival angles of the spacecraft are generalized to be nonsymmetrical. The solutions are shown in terms of the true (ν) and eccentric anomaly (η). The velocity variation (Δ V) required for the transfer is also shown. Then, this study is generalized to consider the possibility that the spacecraft makes a close approach with the mother planet to change its energy in the return trip. The velocity (Δ V) and energy variation (Δ E) due to this passage are obtained. The topics studied here can be applied in missions that leave and come back to the Earth, with the goal of studying the interplanetary space, as well as for missions whose objective is to make an alteration in the energy of the space vehicle through a swing-by with the mother body.

scholarly journals Euclid: Identification of asteroid streaks in simulated images using StreakDet software

2020 ◽  
Vol 644 ◽  
pp. A35
Author(s):  
M. Pöntinen ◽  
M. Granvik ◽  
A. A. Nucita ◽  
L. Conversi ◽  
B. Altieri ◽  
...  
Keyword(s):  
Near Infrared ◽  
Moving Objects ◽  
Infrared Camera ◽  
False Positives ◽  
Apparent Magnitude ◽  
Good Tool ◽  
Infrared Spectrometer ◽  
The Cost ◽  
Near Infrared Spectrometer ◽  
Simulated Images

Context. The ESA Euclid space telescope could observe up to 150 000 asteroids as a side product of its primary cosmological mission. Asteroids appear as trailed sources, that is streaks, in the images. Owing to the survey area of 15 000 square degrees and the number of sources, automated methods have to be used to find them. Euclid is equipped with a visible camera, VIS (VISual imager), and a near-infrared camera, NISP (Near-Infrared Spectrometer and Photometer), with three filters. Aims. We aim to develop a pipeline to detect fast-moving objects in Euclid images, with both high completeness and high purity. Methods. We tested the StreakDet software to find asteroids from simulated Euclid images. We optimized the parameters of StreakDet to maximize completeness, and developed a post-processing algorithm to improve the purity of the sample of detected sources by removing false-positive detections. Results. StreakDet finds 96.9% of the synthetic asteroid streaks with apparent magnitudes brighter than 23rd magnitude and streak lengths longer than 15 pixels (10 arcsec h−1), but this comes at the cost of finding a high number of false positives. The number of false positives can be radically reduced with multi-streak analysis, which utilizes all four dithers obtained by Euclid. Conclusions. StreakDet is a good tool for identifying asteroids in Euclid images, but there is still room for improvement, in particular, for finding short (less than 13 pixels, corresponding to 8 arcsec h−1) and/or faint streaks (fainter than the apparent magnitude of 23).

scholarly journals BEAM Autopilot

2019 ◽  
Author(s):  
Anil Kumar Bheemaiah
Keyword(s):  
Analog Circuits ◽  
Navigation System ◽  
Moving Objects ◽  
Autonomous Systems ◽  
Monocular Camera ◽  
The Earth ◽  
Pilot Design ◽  
The Creation

This paper describes the algorithms and models for a BEAM auto-pilot design with a monocular camera and microphone as sensors, it also describes the creation of an earth mirror using infrasonics for the mapping of stationary and moving objects. Optionally a SLAM and an auto navigation system can be designed using the Earth Mirror(™) and is the topic of a future publication.Key Words: BEAM , MFA I, Earth Mirror, OS , autonomous systems, autopilot, analog circuits, behaviour driven designs,

scholarly journals Detailled Study of The Dynamics of Fragments of Comet C/1996 B2 Hyakutake

1999 ◽  
Vol 172 ◽  
pp. 373-374
Author(s):  
E. Desvoivres ◽  
J. Klinger ◽  
A.C. Levasseur-Regourd
Keyword(s):  
Center Of Mass ◽  
Orbital Plane ◽  
Close Approach ◽  
The Sun ◽  
Keplerian Motion ◽  
Cometary Nuclei ◽  
Gravitational Forces ◽  
The Earth ◽  
Common Center ◽  
Loss Of Mass

The fragmentation of cometary nuclei is a frequent phenomenon, but the dynamics of the fragments is not yet well understood. During the close approach of comet C/1996 B2 Hyakutake to the Earth (0.1 AU) on late March 1996, images were taken with the 1 meter telescope of Pic du Midi observatory. Bright condensations were observed near the nucleus on images taken between March, 22,1996 and March, 31, 1996. It was suggested that these features were mini-comæ surrounding fragments receding from the nucleus (Lecacheux et al., 1996). A model was developped for the motion of cometary fragments in the orbital plane of the comet, and the simulations were compared with the observations (Desvoivres et al, 1998).In the model, we consider that the nucleus of the comet and a fragment are under the influence of the gravity of the Sun, of their mutual gravity, and of non-gravitational forces (NGF) due the loss of mass induced by solar heating. From an estimation of those NGF, we compute numerically the trajectories of the fragment and of the nucleus with respect to their common center of mass (CoM). Then, the motion of the center of mass is studied in an heliocentric reference frame using the theory of perturbed keplerian motion.

The Sensitivity of Barnacles and Their Larvae to Copper and Mercury

1948 ◽  
Vol 25 (3) ◽  
pp. 276-298
Author(s):  
K. A. PYEFINCH ◽  
JOAN C. MOTT
Keyword(s):  
Life History ◽  
Toxic Effect ◽  
Sea Water ◽  
Short Interval ◽  
Sharp Decrease ◽  
Short Exposure ◽  
Sharp Change ◽  
Older Individuals ◽  
Free Swimming ◽  
Wide Range

1. Experiments on the toxic effects of copper and of mercury on various stages in the life history, nauplii, cyprids, metamorphosing cyprids and adults of acorn barnacles are described. Most of the work has been carried out on the appropriate stages of Balanus balanoides, but it has been supplemented, wherever possible, by parallel experiments using B. crenatus. 2. Cupric sulphate and mercuric chloride solutions were used as sources of the poisons, and the actual concentration of poison present was determined at the end of each experiment. The period of exposure to the poison was usually 6 hr. 3. A sharp decrease in sensitivity occurs, both in B. balanoides and B. crenatus, between the last naupliar stage and the cyprid. The relative sensitivity of the cyprid of B. balanoides to copper and to mercury is similar to that of the sixth stage nauplius, but the cyprid of B. crenatus is particularly insensitive to copper, but is more sensitive to mercury than that of B. balanoides. 4. Cyprids of B. balanoides only settle in the laboratory some 4 or 5 days after being taken in the plankton and during this period the sensitivity to copper and mercury increases. Settlement can be prevented by very low concentrations of copper and mercury, even though there are no obvious lethal effects. The cyprid of B. crenatus settles more readily in the laboratory, and little change in sensitivity seems to occur during the short interval between catching and settlement. 5. Metamorphosis of the cyprid of either B. balanoides or B. crenatus cannot be prevented by the concentrations of copper (up to 7 mg./l.) possible in sea water. This means that another sharp change in sensitivity occurs after the cyprid of the former species has settled but, because of the low sensitivity of the free-swimming cyprid of B. crenatus, such a change has not been detected for this species. 6. The young barnacle of both species immediately after metamorphosis is much more sensitive to copper than the metamorphosing cyprid. For B. balanoides the sensitivity, both to this poison and to mercury does not change significantly as the barnacle grows, but a small specimen of B. crenatus (less than one month old) is appreciably less sensitive, both to copper and to mercury, than slightly older individuals. 7. Copper and mercury appear to be roughly equi-toxic to the adult of B. balanoides; the adult B. crenatus is slightly more sensitive to copper and distinctly less sensitive to mercury than that of B. balanoides. 8. In view of these differences in sensitivity of the various stages in the life history of two closely related species, the results obtained with one species should not be held to apply to other species of barnacles. 9. A number of other experiments were carried out using the free-swimming cyprids of B. balanoides. Diluted sea water, though it has no toxic effect in itself over short exposure periods, markedly reduces the toxicity of both copper and mercury. Hypertonic sea water also reduces the toxicity of copper. The sensitivity of these larvae to either copper or mercury is not affected by the presence of sodium oleate. Exposure of these larvae to a wide range of copper concentrations in artificial sea water reveals certain anomalies which may be important in explaining the results obtained when they are exposed to mixtures of copper and mercury in natural sea water. The toxic effect of mercury seems to be similar in either natural or artificial sea water.

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