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مصطلح في المعجم: العنقود النجمي الكروي

الوصف: العنقود النجمي الكروي هو تجمع ضخم وكثيف من النجوم على شكل كروي، مترابط بفعل الجاذبية ومستقر على مدى مليارات السنين. في مجرة درب التبانة، تتكوّن العناقيد الكروية من نجوم قديمة جداً، يتراوح عمرها عموماً بين 11 و13 مليار سنة، مما يجعلها من أقدم الأجرام في المجرة.

في معظم العناقيد الكروية، تكون جميع النجوم المكوِّنة لها قد تشكّلت تقريباً في نفس الفترة الزمنية، على الرغم من أن بعض العناقيد تُظهر دلائل على وجود أجيال متعددة من النجوم.

تضم مجرة درب التبانة نحو 160 عنقوداً كروياً، تتمركز معظمها في هالتها النجمية، في حين أن المجرات الإهليلجية العملاقة يمكن أن تحتوي على عدة آلاف من هذه العناقيد.

مصطلحات ذات صلة:



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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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بلغات أخرى

وسائط ذات صلة


عناقيد نجمية بألوان مختلفة. تتركز النجوم بشكل كبير في وسط الصورة

نجوم في عنقود نجمي كروي بالقرب من قلب مجرة درب التبانة

الشرح: صورة التقطت بواسطة تلسكوب هابل الفضائي تُظهر المساحات الداخلية للعنقود النجمي الكروي الكثيف طرزان 9 الذي يتكون من ملايين النجوم الموجودة بالقرب من قلب مجرتنا مجرة درب التبانة. يقع هذا العنقود الكروي داخل الانتفاخ المجري المركزي وسط الغبار البين نجمي، الذي يحجب الضوء عن هذه العناقيد النجمية. هذه الصورة عبارة عن مزيج من الضوء الذي رصد في مدى الاشعة المرئية والأشعة تحت الحمراء من الطيف الكهرومغناطيسي. يساعد التصوير متعدد الأطوال الموجية على تحديد عمر النجوم وبالتالي عمر العناقيد النجمية الأم.
المصدر: حقوق الصورة تعود الى: وكالة الفضاء الاوربية/تلسكوب هابل و وكالة ناسا الفضائية، ر. كوهين رابط المصدر

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الرسوم التوضيحية المرتبطة


Scorpius appears as a letter T joined to a letter J. The ecliptic runs ESE to WNW and clips one arm of the T

Scorpius Constellation Map

الشرح: The constellation Scorpius (often commonly called Scorpio) along with its bright stars and surrounding constellations. Scorpius is surrounded by (going clockwise from the top) Ophiuchus, Serpens Caput, Libra, Lupus, Norma, Ara, Corona Australis and Sagittarius. Scorpius’s brightest star Antares appears in the heart of the constellation with the famous tail of Scoprius in the south-east (lower left). Scorpius 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 only spends a short amount of time in late November in Scorpius. The other planets of the Solar System can often be found in Scorpius. Scorpius lies south of the celestial equator. The whole constellation is not visible from the most arctic regions of the world with parts of Scorpius obscured for observers in northern parts of Asia, Europe and North America. Scorpius is most visible in the evenings in the northern hemisphere summer and southern hemisphere winter. The yellow circles mark the positions of the open clusters M6, M7 & NGC 6231 while the yellow circles with plus signs superimposed on them mark the globular clusters M4 and M80. 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 circle around Antares indicates that it is a variable star. 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. The blue line marks the ecliptic, the path the Sun appears to travel across the sky over the course of one year. Neither the constellation boundaries, nor the line marking the ecliptic, nor the lines joining the stars appear on the sky.
المصدر: Adapted by the IAU Office of Astronomy for Education from the original by IAU/Sky & Telescope

License: CC-BY-4.0 المشاع الإبداعي نَسب المُصنَّف 4.0 دولي (CC BY 4.0) أيقونات


Sagittarius is shaped like a teapot pouring tea south west. The ecliptic runs WSW to ENE at the top of the constellation

Sagittarius Constellation Map

الشرح: The constellation Sagittarius along with its bright stars and surrounding constellations. Sagittarius is surrounded by (going clockwise from the top) Aquila, Scutum, Serpens Cauda, Ophiuchus, Scorpius, Corona Australis, Telescopium, Microscopium and Capricornus. The brighter stars in Sagittarius form a distinctive teapot shape. Sagittarius 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 Sagittarius from mid December to mid January. The other planets of the Solar System can often be found in Sagittarius. Sagittarius lies south of the celestial equator. The famous teapot asterism is visible for all but the most arctic regions of the world but the most southerly parts of the constellation are not visible in northern parts of Asia, Europe and North America. Sagittarius is most visible in the evenings in the northern hemisphere summer and southern hemisphere winter. The supermassive black hole Sagittarius A* which lies at the center of our Milky Way Galaxy is sits on the western (here right-hand) edge of Sagittarius. Due to it covering an area at the center of our Galaxy, Sagittarius is home to many star clusters including open clusters (marked here with yellow circles) and globular clusters (marked here with yellow circles with + signs superimposed on them). Three nebulae are also marked here with green squares. 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 line marking the ecliptic, nor the lines joining the stars appear on the sky.
المصدر: Adapted by the IAU Office of Astronomy for Education from the original by IAU/Sky & Telescope

License: CC-BY-4.0 المشاع الإبداعي نَسب المُصنَّف 4.0 دولي (CC BY 4.0) أيقونات


Capricornus appears as a downward pointing isosceles triangle. The ecliptic runs through the center from WSW to ENE

Capricornus Constellation Map

الشرح: The constellation Capricornus (commonly called Capricorn) including its bright stars and surrounding constellations. Capricornus is surrounded by (going clockwise from the top) Aquarius, Aquila, Sagittarius, Microscopium and Piscis Austrinus. Capricornus 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 Capricornus from mid January to mid February. The other planets of the Solar System can often be found in Capricornus. Capricornus lies just south of the celestial equator and is visible to all observers south of the Arctic Circle. Capricornus is most visible in the evenings in the northern hemisphere autumn and southern hemisphere spring. In the south east (lower left on this diagram) of the constellation one can find the globular cluster M30 (shown here as a yellow circle with a plus sign superimposed on it). 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 line marking the ecliptic, nor the lines joining the stars appear on the sky.
المصدر: Adapted by the IAU Office of Astronomy for Education from the original by IAU/Sky & Telescope

License: CC-BY-4.0 المشاع الإبداعي نَسب المُصنَّف 4.0 دولي (CC BY 4.0) أيقونات


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

Aquarius Constellation Map

الشرح: 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 line marking the ecliptic, nor the lines joining the stars appear on the sky.
المصدر: Adapted by the IAU Office of Astronomy for Education from the original by IAU/Sky & Telescope

License: CC-BY-4.0 المشاع الإبداعي نَسب المُصنَّف 4.0 دولي (CC BY 4.0) أيقونات


Ophiuchus appears as a headless stick figure

Ophiuchus Constellation Map

الشرح: The constellation Ophiuchus along with its bright stars and its surrounding constellations. Ophiuchus is surrounded by (going clockwise from the top): Hercules, Serpens Caput, Scorpius, Sagittarius and Serpens Cauda. Ophiuchus is not part of the traditional twelve zodiac constellations but it 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 Ophiuchus from late November to mid December. The other planets of the Solar System can often be found in Ophiuchus. Ophiuchus spans the celestial equator and thus part of the constellation is visible across the whole of the earth at some point in the year. However during the time it is most visible in the evenings (the southern hemisphere winter and northern hemisphere summer) much of the arctic is in perpetual daylight making the stars in the constellation impossible to see. The whole constellation is visible from equatorial and temperate regions of both hemispheres. As Ophiuchus lies close to the galactic center it contains many globular clusters such as M9, M10, M12, M14, M19, M62, and M107. These are marked as yellow circles with plus symbols superimposed. 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 line marking the ecliptic, nor the lines joining the stars appear on the sky.
المصدر: Adapted by the IAU Office of Astronomy for Education from the original by IAU/Sky & Telescope

License: CC-BY-4.0 المشاع الإبداعي نَسب المُصنَّف 4.0 دولي (CC BY 4.0) أيقونات