scholarly journals The past orbit of comet Halley and its meteor stream

1985 ◽  
Vol 83 ◽  
pp. 399-403
Author(s):  
A. Hajduk
Keyword(s):  
Structural Features ◽  
Orbital Elements ◽  
Meteor Stream ◽  
Meteor Streams ◽  
The Past ◽  
Maximum Lifetime ◽  
Check Points ◽  
History Of ◽  
Comet Halley ◽  
Comet Orbit

AbstractThe present paper studies the structural features of the meteor streams associated with Comet Halley deduced from the observations of its meteor showers, as check points of orbital elements in a deeper history of the comet orbit. Libration of the argument of perihelion of the comet and the corresponding displacement of the nodes, as recognized in the distribution of condensations within the stream, allows to estimate the maximum lifetime of the comet in the inner Solar System at about 2 × 105 years.

scholarly journals Lifetime of Meteor Streams Associated with Comet Halley

1991 ◽  
Vol 126 ◽  
pp. 323-326
Author(s):  
M. Hajdukova ◽  
A. Hajduk
Keyword(s):  
Mass Loss ◽  
Structural Features ◽  
Critical Examination ◽  
Meteor Showers ◽  
Orbital Parameters ◽  
Loss Process ◽  
Meteor Streams ◽  
Flux Data ◽  
Large Particles ◽  
Comet Halley

AbstractCritical examination of the orbital parameters of particles ejected from comet Halley rejects the low age hypotheses for meteor showers associ- ated with the comet. The diffusion of the orbits of large particles is too slow for explaining the observed structural features of the stream. The mass-loss process as derived from space observations compared with the mass of the stream of particles deduced from flux data lead to comet lifetimes of the order of 105years.

scholarly journals The orbital evolution of meteor streams at the 2/1 resonance with Jupiter

1985 ◽  
Vol 83 ◽  
pp. 179-180
Author(s):  
Cl. Froeschlé
Keyword(s):  
Major Axis ◽  
Orbital Evolution ◽  
The Sun ◽  
Orbital Elements ◽  
Meteor Stream ◽  
Semi Major Axis ◽  
Meteor Streams ◽  
Gravitational Forces ◽  
Resonant Effect

We investigated the orbital evolution of Quadrantid-like meteor streams situated in the vicinity of the 2/1 resonance with Jupiter. For the starting orbital elements we took the values of the orbital elements of the Quadrantid meteor stream except for the semi-major axis which was varied between a = 3.22 and a = 3.34 AU. We considered these meteor streams as a ring and we investigated the resonant effect on the dispersion of this ring over a period of 13 000 years. Only gravitational forces due to the Sun and due to Jupiter were taken into account.

The structure of meteor streams associated with Comet Halley: Eta Aquarids and Orionids

1974 ◽  
Vol 22 ◽  
pp. 309-311
Author(s):  
Anton Hajduk
Keyword(s):  
Density Distribution ◽  
Meteor Shower ◽  
Point Of View ◽  
Orbital Elements ◽  
Statistical Point ◽  
Radar Observations ◽  
Meteor Streams ◽  
Stream Structure ◽  
Comet Halley ◽  
Radar Meteor

The association of Comet Halley with the Orionid and Eta Aquarid meteor streams is not commonly accepted at present. Southworth (1961) has determined the differences in the orbital elements of the Orionid stream and Comet Halley on the basis of 19 photographic meteors and found them to be rather large.Extensive observational material obtained since the beginning of this century, including a homogeneous series of the radar observations, carried out at the Springhill Meteor Observatory during the periods of the Orionid meteor shower activity in 1957–1967 has been used by the author (Hajduk 1971) to study the stream structure and its association with Comet Halley from a statistical point of view.The present analysis is an extension of the paper mentioned, based mainly on the radar observations of the Eta Aquarid meteor shower carried out at the Springhill Observatory during the period 1958–67. The total number of 240,000 radar meteor echoes observed in 670 hours between May 1 and May 10 during each of the years previously cited was used in this investigation. The observed variations in the hourly rates of echoes of different duration enable us to study the density distribution and size distribution of meteoric particles along and across the stream.

Giotto observations of Comet Halley dust

1987 ◽  
Vol 323 (1572) ◽  
pp. 381-395 ◽  
Keyword(s):  
Loss Rate ◽  
Past History ◽  
Mass Loss Rate ◽  
Cometary Nucleus ◽  
Dark Side ◽  
The Past ◽  
History Of ◽  
Side Emission ◽  
Comet Halley ◽  
Impact Data

Measurements of the dust environment of Comet P/Halley by the dust experiments on the Giotto and Vega spacecraft are discussed, as well as some aspects of the dust modelling that was carried out before the spacecraft encounters with the comet. These data have highlighted certain shortcomings in the models. For example, significant fluxes of grains ( m < 10 -17 kg) smaller than allowed by the models have been detected, as well as a far higher ratio than predicted of light to dark side emission from the cometary nucleus. The mass-loss rate is determined and implications for the past history of the comet are discussed. It is also shown how the dust-impact data from the spacecraft experiments can be used to derive information on the distribution of emission over the surface of the nucleus.

scholarly journals The past and future of 1983 TB and its relationship to the geminid meteor stream

1985 ◽  
Vol 83 ◽  
pp. 143-148
Author(s):  
Ken Fox ◽  
Iwan P. Williams ◽  
J. Hunt
Keyword(s):  
Meteor Stream ◽  
The Past ◽  
The Earth ◽  
History Of

AbstractIt is now well known that object 1983 TB, discovered by IRAS, has an orbit very similar to that of the Geminid meteor stream. Calculations show that this orbit crossed over the orbit of Venus about 500 years ago. We will describe calculations tracing the history of both the object and the stream through this interaction with Venus and the present interaction with the Earth.

scholarly journals The Core of the Meteor Stream Associated with Comet Halley

1980 ◽  
Vol 90 ◽  
pp. 149-152
Author(s):  
Anton Hajduk
Keyword(s):  
Structural Features ◽  
Meteor Radar ◽  
Meteor Stream ◽  
The Core ◽  
Comet Halley

Data on 240,000 meteor echoes recorded in 1958-1967 with the Springhill Meteor Radar, have been used for determining the structural features of the Eta Aquarid stream. A zone with a distinct enhancement in meteor rates was located at solar longitudes of 43° to 47°. The core of the stream, corresponding to the four peak days, extends from the orbit of the comet to a distance of 0.08 A.U. Other observations, from both hemispheres, support these results.

On The Possibility of an Autonomous History of Modern Southeast Asia

1961 ◽  
Vol 2 (2) ◽  
pp. 73-105 ◽  
Author(s):  
John R. W. Small
Keyword(s):  
Southeast Asia ◽  
Contemporary History ◽  
The Past ◽  
History Of

It is generally accepted that history is an element of culture and the historian a member of society, thus, in Croce's aphorism, that the only true history is contemporary history. It follows from this that when there occur great changes in the contemporary scene, there must also be great changes in historiography, that the vision not merely of the present but also of the past must change.

Stellar Evolution

1962 ◽  
Vol 11 (02) ◽  
pp. 137-143
Author(s):  
M. Schwarzschild
Keyword(s):  
Solar System ◽  
Stellar Evolution ◽  
Space Craft ◽  
New Techniques ◽  
Substantial Body ◽  
Individual Stars ◽  
The Past ◽  
Evolution Of Galaxies ◽  
History Of ◽  
Fast Flow

It is perhaps one of the most important characteristics of the past decade in astronomy that the evolution of some major classes of astronomical objects has become accessible to detailed research. The theory of the evolution of individual stars has developed into a substantial body of quantitative investigations. The evolution of galaxies, particularly of our own, has clearly become a subject for serious research. Even the history of the solar system, this close-by intriguing puzzle, may soon make the transition from being a subject of speculation to being a subject of detailed study in view of the fast flow of new data obtained with new techniques, including space-craft.

Study of the Molecular Architecture of Keratin Filaments by Electron Microscopy

1982 ◽  
Vol 40 ◽  
pp. 118-119
Author(s):  
U. Aebi ◽  
P. Rew ◽  
T.-T. Sun
Keyword(s):  
Electron Microscopy ◽  
Structural Organization ◽  
Cell Types ◽  
Structural Features ◽  
Molecular Architecture ◽  
The Past ◽  
Keratin Filaments ◽  
Different Types ◽  
10 Nm Filaments ◽  
Different Cell Types

Various types of intermediate-sized (10-nm) filaments have been found and described in many different cell types during the past few years. Despite the differences in the chemical composition among the different types of filaments, they all yield common structural features: they are usually up to several microns long and have a diameter of 7 to 10 nm; there is evidence that they are made of several 2 to 3.5 nm wide protofilaments which are helically wound around each other; the secondary structure of the polypeptides constituting the filaments is rich in ∞-helix. However a detailed description of their structural organization is lacking to date.

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