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Halley's Comet
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Légende : Halley’s Comet, is a well-known periodic comet, named after the English astronomer Edmond Halley. It has an orbital period of approximately 75 years and is visible from Earth with the naked eye when it passes through the inner solar system.
The image shows Halley’s Comet, officially designated 1P/Halley, with a tail of gas and dust streaming away from the Sun. It was taken from the La-Silla-Observatory in Chile in 1986 during Halley's Comet's last visit to the inner solar system. The stars in this image appear elongated or as lines of three different colored dots as image was created from three separate observations in different colors of light and the telescope was tracking the comet, which was moving very slightly compared to the background stars. Note that the comets tail does not point in exactly the same direction as the elongation of the stars. This shows us that the comet tail is not always behind the comet, but instead pointing away from the Sun.
The comet passes its perihelion (closest distance to the Sun) at a distance of around 0.59 astronomical units, right between the orbits of Mercury and Venus. Beyond Neptune, it reaches its aphelion (furthest distance from the Sun) at a distance of approximately 35 astronomical units. Halley's Comet reached aphelion in December 2023 and is now moving inwards again. It is expected to be seen with the naked eye from Earth again in mid-2061.
Crédit : ESO
Lien du crédit
Termes du glossaire:
Aphélie , Comète , Queue cométaire , La comète de Halley , Périhélie
Licence : Creative Commons (CC) Attribution 4.0 International (CC BY 4.0) Creative Commons (CC) Attribution 4.0 International (CC BY 4.0) Icônes
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5.23 MB)
La comète 67P/Tchourioumov-Guérassimenko
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Légende : Le noyau de la comète 67P/Tchourioumov-Guérassimenko (ou 67P/Чурюмова — Герасименко en Russe) est une "boule de neige sale" composée d'un mélange de glaces et de poussières. Il a la forme de deux grands lobes : l'un de 4,1 km × 3,3 km × 1,8 km, l'autre de 2,6 km × 2,3 km × 1,8 km. Ces lobes sont reliés par un petit pont. Lorsqu'un noyau cométaire tel que celui-ci s'approche du Soleil, sa matière gelée et glacée est chauffée et se transforme en gaz. Ce gaz, combiné à la poussière qui s'y trouve, constitue la matière de la coma et de la queue, qui sont caractéristiques de la comète.
Crédit : ESA/Rosetta/NAVCAM
Lien du crédit
Termes du glossaire:
Comète , Noyau de la comète
Catégories :
Système solaire
Licence : Creative Commons (CC) Attribution - Partage dans les Mêmes Conditions 3.0 Organisations Internationales Creative Commons (CC) Attribution - Partage dans les Mêmes Conditions 3.0 Organisations Internationales Icônes
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4.75 MB)
Comète Hale-Bopp
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Légende : Image de la comète C/1995 O1 (Hale-Bopp), prise le 4 avril 1997, avec un temps d'exposition de 10 minutes. Le champ représenté est d'environ 6,5°x6,5°. Deux queues s'étendent à partir de la chevelure brillante : une queue de poussière blanche-jaunâtre, orientée à l'opposé du déplacement de la comète et une queue de gaz bleuâtre, orientée à l'opposé du Soleil.
Crédit : E. Kolmhofer, H. Raab ; Observatoire Johannes Kepler, Linz, Autriche
Lien du crédit
Termes du glossaire:
Comète , Queue cométaire
Catégories :
Système solaire
Licence : Creative Commons (CC) Attribution - Partage dans les Mêmes Conditions 3.0 non transposé Creative Commons (CC) Attribution - Partage dans les Mêmes Conditions 3.0 non transposé Icônes
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882.93 kB)
An Encounter With Halley's Comet
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Légende : This image shows the solid core, or nucleus, of Halley’s Comet, captured in 1986 by the European Space Agency spacecraft Giotto during its flyby of the comet in the inner Solar System. The nucleus appears irregular and potato-shaped, measuring roughly 15 kilometers (about 9 miles) across, and is composed of a mixture of ice, dust, and rock. Unlike the glowing fuzzy cloud (coma) and long tail that make comets visible from Earth, the nucleus itself is dark and difficult to see until a spacecraft passes close enough to take detailed images.
Halley’s Comet is one of the best-known comets because it returns to the inner Solar System approximately every 76 years, allowing generations of astronomers to observe it repeatedly. The material that is released from the nucleus as the comet warms near the Sun forms a glowing coma and long tails of gas and dust, and over many returns leaves trails of debris that produce meteor showers on Earth, such as the Eta Aquarids in May and the Orionids in October.
Crédit : NASA/ESA/Giotto Project
Lien du crédit
Termes du glossaire:
La chevelure (ou coma) de comète , Comète , Noyau de la comète , La comète de Halley
Licence : Domaine Public Domaine Public Icônes
Fichier
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Hello Comet, shall we dance?, by Robert Barsa, Slovakia
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Créé pour l'OAE
Légende : Third place in the 2021 IAU OAE Astrophotography Contest, category Comets.
This beautiful and poetic image taken from Slovakia in July 2020 captures the comet C/2020 F3 (Neowise). The direction of the tails of the comet provides a clue as to the position of the Sun. In the past, the appearance of a comet in the skies could be accompanied by apprehension and even fear from those who did not know what these objects really are. Through careful observations and the applications of knowledge from physics, chemistry and geology, we now understand that comets are objects left over from the earliest days when the Solar System formed. The most distinctive features of a comet are the bluish ion (gas) tail, and whitish dust tail, which can extend for tens of millions of kilometres. These distinctive features, easily observable with the unaided eye together with an understanding of the science, are no longer cause for fear, rather they help us understand the history of our Solar System, and bring awe, joy and contemplation, as portrayed in this image.
Crédit : Robert Barsa/IAU OAE
Termes du glossaire:
Comète , Queue cométaire
Catégories :
Astronomie à l'œil nu
, Système solaire
Licence : Creative Commons (CC) Attribution 4.0 International (CC BY 4.0) Creative Commons (CC) Attribution 4.0 International (CC BY 4.0) Icônes
Ce fichier est sur Zenodo ( image 2.59 MB)
