scholarly journals Dynamics of the Leonid Meteoroid Stream: a Numerical Approach

1996 ◽  
Vol 150 ◽  
pp. 113-116 ◽  
Author(s):  
P. Brown ◽  
J. Jones
Keyword(s):  
Radiation Pressure ◽  
Numerical Approach ◽  
True Anomaly ◽  
Ejection Velocity ◽  
Peak Activity ◽  
Meteoroid Stream ◽  
Subsequent Evolution ◽  
Test Particles ◽  
Model Predictions ◽  
Comet Orbit

AbstractWe have simulated the evolution of the Leonid stream via numerical integration of 3 million test particles ejected from 55P/Tempel-Tuttle during five perihelion passages of that comet. Using the Whipple ejection velocity formula and a random ejection spread in true anomaly about the parent comet orbit inside 2.3 AU, we have followed the subsequent evolution of Leonid meteoroids differing by over 5 orders of magnitude in mass under the influence of radiation pressure and planetary perturbations. By comparing the model predictions of Leonid activity on a year by year basis with the available observations we have attempted to determine roughly the time of ejection associated with each Leonid storm occurrence and model the observed mass distribution. On the basis of the demonstrated accuracy of the model we make predictions regarding times of peak activity and relative strengths for the Leonid returns for each year during the latter part of the 1990s.

scholarly journals Radiation-Driven Stellar Eruptions

Galaxies ◽  
2020 ◽  
Vol 8 (1) ◽  
pp. 10 ◽  
Author(s):  
Kris Davidson
Keyword(s):  
Mass Loss ◽  
Radiation Pressure ◽  
Central Region ◽  
Massive Stars ◽  
Variable Stars ◽  
Blast Waves ◽  
Subsequent Evolution ◽  
Fundamental Causes ◽  
Radiative Output ◽  
Luminous Blue Variable

Very massive stars occasionally expel material in colossal eruptions, driven by continuum radiation pressure rather than blast waves. Some of them rival supernovae in total radiative output, and the mass loss is crucial for subsequent evolution. Some are supernova impostors, including SN precursor outbursts, while others are true SN events shrouded by material that was ejected earlier. Luminous Blue Variable stars (LBV’s) are traditionally cited in relation with giant eruptions, though this connection is not well established. After four decades of research, the fundamental causes of giant eruptions and LBV events remain elusive. This review outlines the basic relevant physics, with a brief summary of essential observational facts. Reasons are described for the spectrum and emergent radiation temperature of an opaque outflow. Proposed mechanisms are noted for instabilities in the star’s photosphere, in its iron opacity peak zones, and in its central region. Various remarks and conjectures are mentioned, some of them relatively unfamiliar in the published literature.

Modelling Primary Production in Water Bodies: A Numerical Approach that Allows Vertical Inhomogeneities

1973 ◽  
Vol 30 (10) ◽  
pp. 1469-1473 ◽  
Author(s):  
Everett J. Fee
Keyword(s):  
Primary Production ◽  
Algal Biomass ◽  
Numerical Approach ◽  
Light Responses ◽  
Phytoplankton Primary Production ◽  
Basic Approach ◽  
Mathematical Solution ◽  
Model Predictions ◽  
Vertical Variations

A new model for computing integral daily phytoplankton primary production is described. The model incorporates vertical variations of algal biomass, complex photosynthesis vs. light responses, nonexponential extinction of light vs. depth, and any distribution of surface light over a day. The basic approach is to combine measured relations for photosynthetic rate vs. light, light vs. depth, and light vs. time in an interpolative scheme rather than attempting to fit equations to the data and using the resulting equations to obtain a mathematical solution. The model is general and should have wide applicability. Model predictions agreed well with in situ measurements of production.

scholarly journals Origin and Evolution of Recent Leonid Meteor Showers

1971 ◽  
Vol 13 ◽  
pp. 193-198 ◽  
Author(s):  
Bruce A. McIntosh
Keyword(s):  
Radiation Pressure ◽  
Ejection Velocity ◽  
Meteor Showers ◽  
Small Particles ◽  
Origin And Evolution ◽  
The Past ◽  
Long Duration ◽  
Large Particles ◽  
Particle Orbits ◽  
Perihelion Passage

The four most prominent returns of the Leonid shoiver in the past decade fall into two broad classes. The 1966 and 1969 showers were of short duration, had a high proportion of small particles, and occurred with the longest apparent delay after the perihelion passage of the parent comet Temple-Tuttle. By contrast, the 1961 and 1965 returns were of long duration, and had more large particles. The 1961 return preceded the comet.There are three major influences on particle orbits: ejection velocity, radiation pressure, and close encounters with planets. The observations are explainable in a qualitative way on the basis of the first two. But some speculation concerning the results of planetary perturbations must be invoked.

scholarly journals Dynamic and Probabilistic Relation between Meteoroids and their Parent Bodies

1996 ◽  
Vol 150 ◽  
pp. 133-136
Author(s):  
Lars G. Adolfsson ◽  
Bo Å. S. Gustafson
Keyword(s):  
Solar Wind ◽  
Radiation Pressure ◽  
Parent Body ◽  
The Sun ◽  
Ejection Velocity ◽  
Meteor Stream ◽  
Level Of Activity ◽  
Ejection Process ◽  
Probabilistic Relation ◽  
Cometary Activity

AbstractWe estimate the probability that specific meteoroids were produced by a specific parent body and obtain the ejection velocity and several other conditions of the ejection as a by-product. The duration of cometary activity leading to a meteor stream, or the epoch of a collision can be estimated from the ejection times of meteoroids in the same stream. The level of activity of a comet or probability of asteroid collisions can be estimated from the part of the orbit where ejection took place. We show that Phaethon ejected Geminid meteoroids over at least 3000 years lasting to as recently as ≈ AD 1600. Ejections are predominantly in the direction of the sun, i.e., from Phaethon's day side, and give insights into the ejection process which is suggestive of cometary activity. Our calculations account for the uncertainty in the observational data and include the effects of planetary perturbations, radiation pressure, Poynting-Robertson light drag and solar wind corpuscular drag.

scholarly journals Eddington capture sphere around luminous relativistic stars

2014 ◽  
Vol 10 (S312) ◽  
pp. 131-134
Author(s):  
Maciek Wielgus
Keyword(s):  
Radiation Pressure ◽  
Radiation Balance ◽  
Spherically Symmetric ◽  
Relativistic Stars ◽  
Strong Gravity ◽  
Effective Force ◽  
Spacetime Curvature ◽  
Test Particles ◽  
Star Surface ◽  
Symmetric Spacetime

AbstractWe discuss the interplay of gravity and radiation in a static, spherically symmetric spacetime. Because of the spacetime curvature, balance between radiation pressure from spherical star and effective force of gravity may be established in a particular distance from the star surface, on so-called Eddington capture sphere. This is in contrast with the Newtonian scenario, for which Eddington luminosity of the radiation assures gravity-radiation balance at any radius. We explore properties of this relativistic equilibrium and the dynamics of test particles under radiation influence in the strong gravity regime.

scholarly journals Modelling of Solar Radiation Pressure Effects: Parameter Analysis for the MICROSCOPE Mission

2015 ◽  
Vol 2015 ◽  
pp. 1-14 ◽  
Author(s):  
Meike List ◽  
Stefanie Bremer ◽  
Benny Rievers ◽  
Hanns Selig
Keyword(s):  
Solar Radiation ◽  
Surface Properties ◽  
Radiation Pressure ◽  
Solar Radiation Pressure ◽  
Numerical Approach ◽  
Pressure Effects ◽  
Parameter Analysis ◽  
Optical Surface ◽  
Satellite Geometry ◽  
Conventional Models

Modern scientific space missions pose high requirements on the accuracy of the prediction and the analysis of satellite motion. On the one hand, accurate orbit propagation models are needed for the design and the preparation of a mission. On the other hand, these models are needed for the mission data analysis itself, thus allowing for the identification of unexpected disturbances, couplings, and noises which may affect the scientific signals. We present a numerical approach for Solar Radiation Pressure modelling, which is one of the main contributors for nongravitational disturbances for Earth orbiting satellites. The here introduced modelling approach allows for the inclusion of detailed spacecraft geometries, optical surface properties, and the variation of these optical surface properties (material degradation) during the mission lifetime. By using the geometry definition, surface property definitions, and mission definition of the French MICROSCOPE mission we highlight the benefit of an accurate Solar Radiation Pressure modelling versus conventional methods such as the Cannonball model or a Wing-Box approach. Our analysis shows that the implementation of a detailed satellite geometry and the consideration of changing surface properties allow for the detection of systematics which are not detectable by conventional models.

scholarly journals Meteoroid-stream complex originating from comet 2P/Encke

2019 ◽  
Vol 623 ◽  
pp. A13 ◽  
Author(s):  
D. Tomko ◽  
L. Neslušan
Keyword(s):  
Dynamical Evolution ◽  
Meteor Shower ◽  
Meteoroid Stream ◽  
The Past ◽  
Test Particles ◽  
Short Period Comet ◽  
Short Period ◽  
The Mean ◽  
Period Comet

Aims. We present a study of the meteor complex of the short-period comet 2P/Encke. Methods. For five perihelion passages of the parent comet in the past, we modeled the associated theoretical stream. Specifically, each of our models corresponds to a part of the stream characterized with a single value of the evolutionary time and a single value of the strength of the Poynting–Robertson effect. In each model, we follow the dynamical evolution of 10 000 test particles via a numerical integration. The integration was performed from the time when the set of test particles was assumed to be ejected from the comet’s nucleus up to the present. At the end of the integration, we analyzed the mean orbital characteristics of those particles that approached the Earth’s orbit, and thus created a meteor shower or showers. Using the mean characteristics of the predicted shower, we attempted to select its real counterpart from each of five considered databases (one photographic, three video, and one radio-meteor). If at least one attempt was successful, the quality of the prediction was evaluated. Results. The modeled stream of 2P approaches the Earth’s orbit in several filaments with the radiant areas grouped in four cardinal directions of ecliptical showers. These groups of radiant areas are situated symmetrically with respect to the apex of the Earth’s motion around the Sun. Specifically, we found that showers #2, #17, #156, #172, #173, #215, #485, #624, #626, #628, #629, #632, #634, #635, #636, and #726 in the IAU-MDC list of all showers are dynamically related to 2P. In addition, we found five new 2P-related showers in the meteor databases considered.

scholarly journals Modeling of the meteoroid stream of comet C/1975 T2 and λ-Ursae Majorids

2019 ◽  
Vol 627 ◽  
pp. A73 ◽  
Author(s):  
M. Hajduková ◽  
L. Neslušan
Keyword(s):  
Dynamical Evolution ◽  
Parent Body ◽  
Meteor Shower ◽  
Evolutionary Time ◽  
Meteoroid Stream ◽  
Test Particles ◽  
International Astronomical ◽  
The Mean ◽  
Almost All ◽  
Meteor Data

Aims. We study the meteoroid stream of the long-period comet C/1975 T2 (Suzuki-Saigusa-Mori). This comet was suggested as the parent body of the established λ-Ursae Majorid meteor shower, No. 524. Methods. We modeled 32 parts of a theoretical meteoroid stream of the parent comet considered. Each of our models is characterized with a single value of the evolutionary time and a single value of the strength of Poynting-Robertson effect. The evolutionary time ranges from 10 000 to 80 000 yr. It is the period during which the evolution of the stream part is followed. In each model, the dynamical evolution of 10 000 test particles was then followed, via a numerical integration, from the time of the modeling up to the present. At the end of the integration, we analyzed the mean orbital characteristics of particles in the orbits that approach the Earth’s orbit, which thus enabled us to predict a shower related to the parent comet. The predicted shower was subsequently compared with its observed counterparts. We separated the latter from the databases of real meteors. As well, we attempted to identify the predicted shower to a shower recorded in the International Astronomical Union Meteor Data Center (IAU MDC) list of all showers. Results. Almost all modeled parts of the stream of comet C/1975 T2 are identified with the corresponding real shower in three video-meteor databases. No real counterpart is found in the IAU MDC photographic or radio-meteor data. In the IAU MDC list of showers and in our current study, this shower is identified with the established λ-Ursae Majorid shower, No. 524. Hence, our modeling confirms the results of previous authors. At the same time we exclude an existence of other meteor shower associated with C/1975 T2.

scholarly journals Effects of Radiation Pressure on the Elliptic Restricted Four-Body Problem

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Sahar H. Younis ◽  
M. N. Ismail ◽  
Ghada F. Mohamdien ◽  
A. H. Ibrahiem
Keyword(s):  
Radiation Pressure ◽  
Body Problem ◽  
Equilibrium Points ◽  
Equations Of Motion ◽  
Numerical Approach ◽  
The Earth ◽  
Families Of Periodic Orbits ◽  
Four Body Problem ◽  
The Stability ◽  
Effects Of Radiation

In this paper, under the effects of the largest primary radiation pressure, the elliptic restricted four-body problem is formulated in Hamiltonian form. Moreover, the canonical equations are obtained which are considered as the equations of motion. The Lagrangian points within the frame of the elliptic restricted four-body problem are obtained. The true anomalies are considered as independent variables. An analytical and numerical approach had been used. A code of Mathematica version 12 is constructed to truncate these considerations and is applied on the Earth-Moon-Sun system. In addition, the stability and periodicity of the motion about the equilibrium points are studied by using the Poincare maps. The motion about the collinear point L2 is presented as an example for the obtained results, and some families of periodic orbits are presented.

scholarly journals Controlling the Perturbations of Solar Radiation Pressure on the Lorentz Spacecraft

Symmetry ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 1423
Author(s):  
A. Mostafa ◽  
M. I. El-Saftawy ◽  
Elbaz I. Abouelmagd ◽  
Miguel A. López
Keyword(s):  
Solar Radiation ◽  
Lorentz Force ◽  
Radiation Pressure ◽  
Solar Radiation Pressure ◽  
True Anomaly ◽  
Orbital Parameters ◽  
Numerical Investigations ◽  
Geosynchronous Orbits

The aim of the present paper is to analyze the viability of using Lorentz Force (LF) acting on a charged spacecraft to neutralize the effects of Solar Radiation Pressure (SRP) on the longitude of the ascending node and the argument of perigee of the spacecraft’s orbit. In this setting, the Gauss planetary equations for LF and SRP are presented and averaged over the true anomaly. The averaged variations for the longitude of the ascending node (h) and the argument of perigee (g) are invariant under the symmetry (i,g)⟶(−i,−g) due to Lorentz Force. The sum of change rates due to both perturbing forces of LF and SRP is assigned by zero to estimate the charge amount to balance the variation for the argument of perigee and longitude of ascending. Numerical investigations have been developed to show the evolution of the charge quantity for different orbital parameters at both Low Earth and Geosynchronous Orbits.

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