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Glossarbegriffe: Planetarischer Nebel

Description: Ein planetarischer Nebel ist eine Wolke aus Gas und Staub, die aus den äußeren Schichten eines sterbenden Sterns stammt und sich in das interstellare Medium ausdehnt. Das Gas wird durch das ultraviolette Licht des sterbenden Sterns angeregt und leuchtet mit einem Emissionslinienspektrum. Einige planetarische Nebel sind annähernd kugelförmig und können in einem kleinen Teleskop wie ein Planet aussehen - daher der Name. Aber sie haben nichts mit Planeten zu tun. Andere planetarische Nebel sind nicht kugelförmig. Das ist auf die Rotation des Sterns, sein Magnetfeld oder einen Begleitstern zurückzuführen.

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Term and definition status: The original definition of this term in English have been approved by a research astronomer and a teacher
The translation of this term and its definition is still awaiting approval

The OAE Multilingual Glossary is a project of the IAU Office of Astronomy for Education (OAE) in collaboration with the IAU Office of Astronomy Outreach (OAO). The terms and definitions were chosen, written and reviewed by a collective effort from the OAE, the OAE Centers and Nodes, the OAE National Astronomy Education Coordinators (NAECs) and other volunteers. You can find a full list of credits here. All glossary terms and their definitions are released under a Creative Commons CC BY-4.0 license and should be credited to "IAU OAE".

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Related Diagrams


The bright stars in Andromeda form a Y-shape. Pegasus to the lower right. In the center is M31, marked with a red ellipse.

Andromeda Constellation Map

Bildunterschriften: The constellation Andromeda showing the bright stars and surrounding constellations. Andromeda is surrounded by (going clockwise from the top) Cassiopeia, Lacerta, Pegasus, Pisces, Aries, Triangulum and Perseus. The brightest star in Andromeda (Alpheratz) is in the lower part of the constellation. Together with three stars in Pegasus it forms the asterism known as the "Great Square of Pegasus". The next two bright stars in the constellation (Mirach and Almach) form a line extending north-east from Alpheratz. Andromeda is a northern constellation and is most visible in the evenings in the Northern Hemisphere autumn. It is visible from all of the Northern Hemisphere and most temperate regions of the Southern Hemisphere but is not visible from Antarctic and Subantarctic regions. The most famous object in Andromeda, the Andromeda Galaxy is marked here with a red ellipse and its Messier catalog number M31. The yellow circle on the left marks the position of the open cluster NGC 752 and the green circle on the right marks NGC 7662 (the blue snowball nebula), a planetary nebula. The y-axis of this diagram is in degrees of declination with north as up and the x-axis is in hours of right ascension with east to the left. The sizes of the stars marked here relate to the star's apparent magnitude, a measure of its apparent brightness. The larger dots represent brighter stars. The Greek letters mark the brightest stars in the constellation. These are ranked by brightness with the brightest star being labeled alpha, the second brightest beta, etc., although this ordering is not always followed exactly. The dotted boundary lines mark the IAU's boundaries of the constellations and the solid green lines mark one of the common forms used to represent the figures of the constellations. Neither the constellation boundaries, nor the lines joining the stars appear on the sky.
Bildnachweis: Adapted by the IAU Office of Astronomy for Education from the original by IAU/Sky & Telescope

License: CC-BY-4.0 Creative Commons Namensnennung 4.0 International (CC BY 4.0) icons


Aquarius appears as a sprawling series of connected lines. The ecliptic runs through its center from WSW to ENE.

Aquarius Constellation Map

Bildunterschriften: The constellation Aquarius along with its bright stars and surrounding constellations. Aquarius is surrounded by (going clockwise from the top) Pegasus, Equuleus, Aquila, Capricornus, Piscis Austrinus, Sculptor, Cetus and Pisces. Aquarius lies on the ecliptic (shown here as a blue line), this is the path the Sun appears to take across the sky over the course of a year. The Sun is in Aquarius from mid February to mid March. The other planets of the Solar System can often be found in Aquarius. Aquarius spans the celestial equator and is thus visible at some time in the year from all of planet Earth. In the most arctic or antarctic regions of the world, some parts of the constellation may not be visible. Aquarius is most visible in the evenings in the northern hemisphere autumn and southern hemisphere spring. The yellow circles with plus symbols superimposed on them mark the globular clusters M2 and M72. The green circles superimposed on plus symbols mark the planetary nebulae NGC 7293 (the Helix Nebula) and NGC 7002 (the Saturn Nebula). M73 (marked with an x symbol) is a coincident grouping of stars previously erroneously classified as an open cluster. The y-axis of this diagram is in degrees of declination with north as up and the x-axis is in hours of right ascension with east to the left. The sizes of the stars marked here relate to the star's apparent magnitude, a measure of its apparent brightness. The larger dots represent brighter stars. The Greek letters mark the brightest stars in the constellation. These are ranked by brightness with the brightest star being labeled alpha, the second brightest beta, etc., although this ordering is not always followed exactly. The dotted boundary lines mark the IAU's boundaries of the constellations and the solid green lines mark one of the common forms used to represent the figures of the constellations. Neither the constellation boundaries, nor the lines joining the stars appear on the sky.
Bildnachweis: Adapted by the IAU Office of Astronomy for Education from the original by IAU/Sky & Telescope

License: CC-BY-4.0 Creative Commons Namensnennung 4.0 International (CC BY 4.0) icons


Ursa Major appears as a ladle with the handle to the east & the cup to the west. Lines of fainter stars extend to the south

Ursa Major Constellation Map

Bildunterschriften: The constellation Ursa Major along with its bright stars and its surrounding constellations. Ursa Major is surrounded by (going clockwise from the top): Draco, Camelopardalis, Lynx, Leo Minor, Leo, Coma Berenices, Canes Venatici and Boötes. Ursa Major is famous for the prominent asterism often known in English as the Big Dipper or the Plough. This prominent northern asterism has a wide variety of names from cultures across the world. While most constellations and asterisms are made up of unrelated stars that randomly appear close together on the sky, five of the stars in the Big Dipper are part of the Ursa Major Moving Group, a group of stars moving through space together that likely formed in the same location 300 million years ago. The two stars on the right-hand end of the Big Dipper on this diagram form a pair of pointer stars that can be used to locate Polaris, the northern pole star which lies in the constellation of Ursa Minor. Ursa Major is a northern constellation and is visible from northern and equatorial regions. Parts of the constellation are visible from all but the most antarctic parts of the southern hemisphere but not all temperate regions of the southern hemisphere can see all of the Big Dipper. Conversely the Big Dipper and much of the rest of the constellation are circumpolar in arctic and many temperate regions of the northern hemisphere. Ursa Major is most visible in the evening in the northern hemisphere spring and southern hemisphere autumn. Two prominent galaxies appear in the northern part of this constellation, the spiral galaxy M81 and M82, a possible spiral galaxy whose structure is difficult to observe from the Earth as it appears edge-on. Both are shown here as red ellipses. The planetary nebula M97 (the Owl Nebula) lies in the middle of the constellation and is marked by a green circle superimposed on a plus symbol. The y-axis of this diagram is in degrees of declination with north as up and the x-axis is in hours of right ascension with east to the left. The sizes of the stars marked here relate to the star's apparent magnitude, a measure of its apparent brightness. The larger dots represent brighter stars. The Greek letters mark the brightest stars in the constellation. These are ranked by brightness with the brightest star being labeled alpha, the second brightest beta, etc., although this ordering is not always followed exactly. The dotted boundary lines mark the IAU's boundaries of the constellations and the solid green lines mark one of the common forms used to represent the figures of the constellations. Neither the constellation boundaries, nor the lines joining the stars appear on the sky.
Bildnachweis: Adapted by the IAU Office of Astronomy for Education from the original by IAU/Sky & Telescope

License: CC-BY-4.0 Creative Commons Namensnennung 4.0 International (CC BY 4.0) icons