scholarly journals 22. The relation between orbits and physical characteristics of meteors

1968 ◽  
Vol 33 ◽  
pp. 217-235 ◽  
Author(s):  
Ľ. Kresák
Keyword(s):  
Major Axis ◽  
Progressive Increase ◽  
Physical Characteristics ◽  
The Other ◽  
Asteroid Belt ◽  
Angle Of Incidence ◽  
Semi Major Axis ◽  
Short Period ◽  
Broad Variety ◽  
Bona Fide

The relation of physical characteristics of meteors to their orbital elements is investigated using Harvard Super-Schmidt data. A set of characteristic indices is defined, allowing for the effects of geocentric velocity, angle of incidence, magnitude and mass, wherever a correction appears appropriate according to the correlations found by Jacchia et al. (1967). The medians for representative meteor samples are plotted in the semi-major axis/eccentricity diagram and the distribution of each parameter is derived. Although the differences are moderate compared to the measuring errors, six regions of different nature can be distinguished.The existence of two families of asteroidal meteors is indicated, one of them brought to crossing with the Earth's orbit by drag effects and the other by collision effects in the main asteroid belt. These meteors are characterized by low and uniform beginning heights, high fragmentation, low ablation, low deceleration, and bright wakes. A direct counterpart to this is represented by meteors moving in short-period orbits of higher eccentricity and shorter perihelion distance, which bear resemblance to the long-period and retrograde cometary meteors. Meteors with perihelion distances of less than 0·15 AU tend to resemble the bona fide asteroidal meteors by a progressive increase of fragmentation and decrease of reduced beginning heights and decelerations as the perihelion approaches the Sun. This is attributed to the selective destruction effects of solar radiation.With the exception of the Draconids, the mean characteristics of meteor showers agree well with those of sporadic meteors moving in similar orbits. It is suggested that the Draconid stream includes a broad variety of meteoric material and that the two peculiar Super-Schmidt meteors on record represent only the less resistive, short-lived component which has already been eliminated from the other showers.

The system of short period meteor streams

1974 ◽  
Vol 22 ◽  
pp. 269-281 ◽  
Author(s):  
B. A. Lindblad
Keyword(s):  
Major Axis ◽  
Progressive Increase ◽  
Orbital Energy ◽  
The Sun ◽  
Meteor Stream ◽  
Semi Major Axis ◽  
Meteor Streams ◽  
Short Period ◽  
The Mean ◽  
Orbital Periods

AbstractThe orbital characteristics of precisely reduced photographic meteors were studied. Most photographic meteors move in short period, direct orbits with orbital periods inbetween those of Jupiter and Mars. Practically no meteors have (Orbital periods coincident with those of the planets Jupiter, Mars and Earth.A search among all precisely reduced, photographic meteors revealed a number of new – or previously not well studied – meteor streams. For 18 short period meteor streams the scatter in the orbital elements 1/a,πand Ω was studied. An almost linear relation was found between the mean orbital energy of a meteor stream (– 1/a) and the standard deviation σ(1/a), indicating a progressive increase in the orbital scatter with decreasing mean distance to the sun. An index of mean meteoroid density was computed for 11 of the short period streams. The mean density increases with decreasing semi-major axis.The results are interpreted as indicating that the short period meteor streams are initially formed in orbits with periods slightly shorter than Jupiter’s. As the streams gradually drift inwards towards the sun under the influence of various drag forces the individual stream members spread out and only the high density, resistant meteors still remain, or can be recognized, as stream members.

scholarly journals Correspondances Entre Une Theorie Generale Planetaire En Variables Elliptiques Et La Theorie Classique De Le Verrier

1978 ◽  
Vol 41 ◽  
pp. 15-32 ◽  
Author(s):  
L. Duriez
Keyword(s):  
General Theory ◽  
Classical Theory ◽  
Major Axis ◽  
Second Order ◽  
Semi Major Axis ◽  
First Order ◽  
Short Period ◽  
The Masses ◽  
Secular Terms

AbstractIn order to improve the determination of the mixed terms in classical theories, we show how these terms may be derived from a general theory developed with the same variables (of a keplerian nature). We find that the general theory of the first order in the masses already allows us to develop the mixed terms which appear at the second order in the classical theory. We also show that a part of the constant perturbation of the semi-major axis introduced in the classical theory is present in the general theory as very long-period terms; by developing these terms in powers of time, they would be equivalent to the appearance of very small secular terms (in t, t2, …) in the perturbation of the semi-major axes from the second order in the masses. The short period terms of the classical theory are found the same in the general theory, but without the numerical substitution of the values of the variables.

DETERMINATION OF THE ELEMENTS OF METEOR PATHS FROM RADAR OBSERVATIONS

1949 ◽  
Vol 27a (3) ◽  
pp. 53-67 ◽  
Author(s):  
D. W. R. McKinley ◽  
Peter M. Millman
Keyword(s):  
Sea Level ◽  
Path Length ◽  
Major Axis ◽  
Radar Data ◽  
Semi Major Axis ◽  
Radar Observations ◽  
Short Period ◽  
Single Station

Methods of determining meteor velocities from single-station observations are discussed. Where three-station observations are available both the velocity and the elements of the meteor's path through the atmosphere can be computed in favorable cases. These methods are applied to a selected daytime meteor, recorded by the three radar stations at 17h 59m 48s E.S.T., Aug. 4, 1948. The following elements of the meteor's path have been obtained from the radar data:—Apparent geocentric velocity    35.0 ± 0.4 km. per sec.True bearing of apparent radiant    074° ± 2°Elevation of apparent radiant    2° ± 2°Total radar path length    270 km.Height above sea level    108 − 104 km.These values lead to an orbit similar to one of the short-period comets, with these elements:—Semi-major axis    a    2.66Eccentricity    e    0.87Angle node to perihelion    ω    294°.9Longitude of node        132°.4Inclination    i    33°.6Period    P    4.33 years

scholarly journals Orbital Elements of MACHO Project Eclipsing Binary Stars

2005 ◽  
Vol 13 ◽  
pp. 467-467
Author(s):  
Charles Alcock
Keyword(s):  
Binary Stars ◽  
Large Scale ◽  
Major Axis ◽  
Orbital Elements ◽  
Semi Major Axis ◽  
Eclipsing Binary ◽  
Eclipsing Binary Stars ◽  
Large Numbers ◽  
Short Period ◽  
Velocity Information

Large scale photometric surveys can deliver very large numbers of eclipsing binary stars. It is not presently possible to obtain radial velocity information for more than a small fraction of these. We have made some progress in the estimation of the statistical distributions of orbital elements (including semi-major axis and eccentricity) in the MACHO Project catalog of eclipsing binary stars. We see the well-known tendency to circularization in short period orbits and also detect late tidal circularization during the giant phase. The extension of these techniques to newer surveys will also be discussed.

scholarly journals The influence of starspots activity on the determination of planetary transit parameters

2009 ◽  
Vol 5 (S264) ◽  
pp. 440-442 ◽  
Author(s):  
Adriana Silva-Válio
Keyword(s):  
Light Curve ◽  
Major Axis ◽  
The Other ◽  
Semi Major Axis ◽  
Active Star ◽  
Orbital Parameters ◽  
Correct Determination ◽  
The Times ◽  
Parent Star

AbstractAs a planet eclipses its parent star, dark spots on the surface of the star may be occulted, causing a detectable variation in the transit light curve. There are basically two effects caused by the presence of spots on the surface of the star which can alter the shape of the light curve during transits and thus preclude the correct determination of the planet physical and orbital parameters. The first one is that the presence of many spots within the latitude band occulted by the planet will cause the depth of the transit in the light curve to be shallower. This will erroneously result in a smaller radius for the planet. The other effect is that generated by spots located close to the limb of the star. In this case, the spots will interfere in the light curve during the times of ingress or egress of the planet, causing a decrease in the transit duration. This in turn will provide a larger value for the semi-major axis of the planetary orbit. Qualitative estimates of both effects are discussed and an example provided for a very active star, such as CoRoTo-2.

scholarly journals Scaling, Mirror Symmetries and Musical Consonances Among the Distances of the Planets of the Solar System

2022 ◽  
Vol 8 ◽  
Author(s):  
Michael J. Bank ◽  
Nicola Scafetta
Keyword(s):  
Solar System ◽  
Major Axis ◽  
Asteroid Belt ◽  
Semi Major Axis ◽  
Resonance Model ◽  
Orbital Parameters ◽  
Self Organized ◽  
Powers Of 2 ◽  
Specific Finding ◽  
Frequency Ratios

Orbital systems are often self-organized and/or characterized by harmonic relations. Inspired by music theory, we rewrite the Geddes and King-Hele (QJRAS, 24, 10–13, 1983) equations for mirror symmetries among the distances of the planets of the Solar System in an elegant and compact form by using the 2/3rd power of the ratios of the semi-major axis lengths of two neighboring planets (eight pairs, including the belt of the asteroids). This metric suggests that the Solar System could be characterized by a scaling and mirror-like structure relative to the asteroid belt that relates together the terrestrial and Jovian planets. These relations are based on a 9/8 ratio multiplied by powers of 2, which correspond musically to the interval of the Pythagorean epogdoon (a Major Second) and its addition with one or more octaves. Extensions of the same model are discussed and found compatible also with the still hypothetical vulcanoid asteroids versus the transneptunian objects. The found relation also suggests that the planetary self-organization of our system could be generated by the 3:1 and 7:3 resonances of Jupiter, which are already known to have shaped the asteroid belt. The proposed model predicts the main Kirkwood asteroid gaps and the ratio among the planetary orbital parameters with a 99% accuracy, which is three times better than an alternative, recently proposed harmonic-resonance model for the Solar System. Furthermore, the ratios of neighboring planetary pairs correspond to four musical “consonances” having frequency ratios of 5/4 (Major Third), 4/3 (Perfect Fourth), 3/2 (Perfect Fifth) and 8/5 (Minor Sixth); the probability of obtaining this result randomly has a p < 0.001. Musical consonances are “pleasing” tones that harmoniously interrelate when sounded together, which suggests that the orbits of the planets of our Solar System could form some kind of gravitationally optimized and coordinated structure. Physical modeling indicates that energy non-conserving perturbations could drive a planetary system into a self-organized periodic state with characteristics vaguely similar of those found in our Solar System. However, our specific finding suggests that the planetary organization of our Solar System could be rather peculiar and based on more complex and unknown dynamical structures.

scholarly journals Light curve modeling of the short-period W UMa star GSC 02049-01164

2015 ◽  
Vol 11 (A29B) ◽  
pp. 536-539
Author(s):  
Lester Fox-Machado ◽  
Juan Echevarria ◽  
Diego González-Buitrago ◽  
Raul Michel
Keyword(s):  
Binary System ◽  
Light Curve ◽  
Binary Stars ◽  
Binary Star ◽  
Major Axis ◽  
Physical Parameters ◽  
Semi Major Axis ◽  
San Pedro ◽  
Short Period ◽  
Curve Modeling

AbstractThe preliminary results of an analysis of the time-series photometric data of binary star GSC 02049-01164 (ROTSE1 J164341.65+251748.1) are presented. GSC 02049-01164 was observed for eight consecutive nights with the 0.84-m telescope of the San Pedro Martir Observatory in Mexico. The light curve of GSC 02049-01164 is typical of those of W UMa type binary stars. In an effort to gain a better understanding of the binary system and determine its physical properties we have analyzed the light curve with the software PHOEBE V.0 0.31a. We have found that GSC 02049-01164 binary system has a mass ratio of ~ 0.42, an inclination of ~ 85 degrees, a semi-major axis of ~ 2.24 R⊙. It is likely that the two stellar components are in contact, with a degree of overcontact of 13%. The physical parameters of the stellar components have been derived.

scholarly journals The dynamical environment of the primary in the triple asteroid (45) Eugenia

2020 ◽  
Vol 29 (1) ◽  
pp. 59-71
Author(s):  
Min Jiang ◽  
Qingtian Ma
Keyword(s):  
Gravitational Potential ◽  
Effective Potential ◽  
Mechanical Energy ◽  
Equilibrium Points ◽  
Dynamical Behavior ◽  
Major Axis ◽  
Semi Major Axis ◽  
Orbital Parameters ◽  
Short Period ◽  
Zero Velocity Curves

AbstractWe investigated the dynamical behavior in the potential of the primary in the triple asteroid (45) Eugenia with the calculation of the full gravitational potential caused by its 3D irregular shape. We presented the whole structure of the gravitational potential and the effective potential of (45) Eugenia in the coordinate planes, and showed the surface height, surface gravitational force accelerations, and the surface effective potential. The surface gravitational environment has been discussed. The zero-velocity curves and the position of external equilibrium points are calculated and showed relative to the 3D shape of the asteroid to help compare the relationship of the characteristic of the gravitational potential and the shape of the asteroid. There are five equilibrium points in the gravitational potential (45) Eugenia. We presented the positions, eigenvalues, topological cases, and stability of these equilibrium points. To analyze the variety of the orbital parameters close to (45) Eugenia, we computed two different orbits and compared the results. The mechanical energy, the semi-major axis, and the eccentricity have two different periods: the long period and the short period. The inclination have three different periods, an intermediate period is occurred. The longitude of the ascending node and the argument of periapsis not only have two periodic terms, but also have a secular term.

Detection and Characterization of earth-like Planets

1997 ◽  
Vol 161 ◽  
pp. 299-311 ◽  
Author(s):  
Jean Marie Mariotti ◽  
Alain Léger ◽  
Bertrand Mennesson ◽  
Marc Ollivier
Keyword(s):  
Direct Detection ◽  
Contrast Ratio ◽  
Angular Size ◽  
Physical Nature ◽  
Major Axis ◽  
Infrared Emission ◽  
Space Technology ◽  
Semi Major Axis ◽  
Earth Like Planets ◽  
Visible Wavelengths

AbstractIndirect methods of detection of exo-planets (by radial velocity, astrometry, occultations,...) have revealed recently the first cases of exo-planets, and will in the near future expand our knowledge of these systems. They will provide statistical informations on the dynamical parameters: semi-major axis, eccentricities, inclinations,... But the physical nature of these planets will remain mostly unknown. Only for the larger ones (exo-Jupiters), an estimate of the mass will be accessible. To characterize in more details Earth-like exo-planets, direct detection (i.e., direct observation of photons from the planet) is required. This is a much more challenging observational program. The exo-planets are extremely faint with respect to their star: the contrast ratio is about 10−10at visible wavelengths. Also the angular size of the apparent orbit is small, typically 0.1 second of arc. While the first point calls for observations in the infrared (where the contrast goes up to 10−7) and with a coronograph, the latter implies using an interferometer. Several space projects combining these techniques have been recently proposed. They aim at surveying a few hundreds of nearby single solar-like stars in search for Earth-like planets, and at performing a low resolution spectroscopic analysis of their infrared emission in order to reveal the presence in the atmosphere of the planet of CO H2O and O3. The latter is a good tracer of the presence of oxygen which could be, like on our Earth, released by biological activity. Although extremely ambitious, these projects could be realized using space technology either already available or in development for others missions. They could be built and launched during the first decades on the next century.

scholarly journals Some Special Types of Orbits around Jupiter

Aerospace ◽  
2021 ◽  
Vol 8 (7) ◽  
pp. 183
Author(s):  
Yongjie Liu ◽  
Yu Jiang ◽  
Hengnian Li ◽  
Hui Zhang
Keyword(s):  
Gravity Model ◽  
Small Perturbation ◽  
Equilibrium Points ◽  
Major Axis ◽  
Semi Major Axis ◽  
Ground Track ◽  
The Earth ◽  
Degenerate Equilibrium ◽  
The Mean ◽  
Element Theory

This paper intends to show some special types of orbits around Jupiter based on the mean element theory, including stationary orbits, sun-synchronous orbits, orbits at the critical inclination, and repeating ground track orbits. A gravity model concerning only the perturbations of J2 and J4 terms is used here. Compared with special orbits around the Earth, the orbit dynamics differ greatly: (1) There do not exist longitude drifts on stationary orbits due to non-spherical gravity since only J2 and J4 terms are taken into account in the gravity model. All points on stationary orbits are degenerate equilibrium points. Moreover, the satellite will oscillate in the radial and North-South directions after a sufficiently small perturbation of stationary orbits. (2) The inclinations of sun-synchronous orbits are always bigger than 90 degrees, but smaller than those for satellites around the Earth. (3) The critical inclinations are no-longer independent of the semi-major axis and eccentricity of the orbits. The results show that if the eccentricity is small, the critical inclinations will decrease as the altitudes of orbits increase; if the eccentricity is larger, the critical inclinations will increase as the altitudes of orbits increase. (4) The inclinations of repeating ground track orbits are monotonically increasing rapidly with respect to the altitudes of orbits.

Sign in / Sign up

Export Citation Format

Share Document