بلغات أخرى
- الألمانيّة: Brauner Zwerg
- الإنجليزيّة: Brown Dwarf
- الإسبانيّة: Enana marrón
- الفرنسيّة: Naine brune
- الإيطاليّة: Nana bruna
- اليابانيّة: 褐色矮星 (رابط خارجي)
- الكوريّة: 갈색왜성
- البرتغاليّة البرازيليّة: Anã marrom
- الصينيّة المبسطة: 褐矮星
- الصينيّة التقليدية: 褐矮星
وسائط ذات صلة
A binary brown dwarf system revealed
الشرح: This image presents a nearby system of brown dwarfs, objects that fall between planets and stars in mass and do not sustain long-term nuclear fusion in their cores. Located about 6.5 light-years from Earth, this system (known as Luhman 16) is the third closest system to the Solar System after the Alpha Centauri system and Barnard's Star. It was initially observed as what seemed to be a single faint source of infrared light. Brown dwarfs are often difficult to study because of their low brightness, especially in visible light. However they shine brighter in infrared light due to their cooler effective temperatures.
The comparison highlights the importance of observational resolution. The image at the center, taken by NASA’s Wide-field Infrared Survey Explorer (WISE), shows the system as a single blurred object due to its lower resolution (WISE has a resolution of roughly 6 arcseconds). A highlighted zoomed-in view from the Gemini South Observatory in Chile reveals that this “single” source is actually a binary system of two brown dwarfs. The improved angular resolution (roughly 0.6 arcseconds) allows astronomers to separate the two objects clearly, demonstrating how higher-resolution observations uncover hidden structures in the universe. While the Gemini telescope is situated on the Earth and thus is affected by the blurring effects of the Earth's atmosphere, it has a substantially larger mirror than the WISE telescope (8m wide vs. 40cm wide) meaning it can achieve much higher resolutions.
المصدر: NASA/JPL/Gemini Observatory/AURA/NSF
رابط المصدر
License: PD الملكية العامة أيقونات
الرسوم التوضيحية المرتبطة
Hertzsprung-Russell diagram
الشرح: This diagram shows the temperature and luminosity of different stars. The size of each point represents the star’s radius and its colour is the colour the human eye would see. The stars range in colour from a washed-out blue to a washed-out reddish-orange. No star has a pure colour like red, green or blue as stars’ spectra include light from lots of different colours. However the reddest stars are commonly referred to as red and the bluest stars as blue. The sample of stars used to make this diagram was chosen to show a wide range of stars of different types so the relative number of each type of star is not representative of how commonly each type is found.
From the top left to bottom right there is a long line of stars burning hydrogen in their cores. This is called the main sequence. On this line, one sees the stars Mintaka, Achenar, Sirius A, the Sun and Proxima Centauri. The objects around Proxima Centauri at the lower right end of the main sequence are known as red dwarfs. To the lower right of the red dwarfs are Teide 1 and Kelu-1 A. These two objects are brown dwarfs, objects too low in mass to have cores hot enough to fuse hydrogen for a sustained period of time. As they do not burn hydrogen, brown dwarfs are not considered main sequence stars. The name brown dwarf is unrelated to their colour.
Above the main sequence, we find subgiants, giants and supergiants. These are stars that have finished burning hydrogen in their core and have evolved into larger objects. A star’s brightness depends on its temperature and size so giant stars are brighter than stars with a smaller radius but the same temperature. In time these objects will move towards the end of their lives and undergo either a planetary nebula phase or become supernovae. Stars which end their lives with a planetary nebula phase become a type of stellar remnant called a white dwarf. Such objects are much smaller than stars of the same temperature and thus are fainter and are found significantly below the main sequence. Stars which end their lives as supernovae become either black holes or neutron stars. These are not shown on this plot.
المصدر: IAU OAE/Niall Deacon
License: CC-BY-4.0 المشاع الإبداعي نَسب المُصنَّف 4.0 دولي (CC BY 4.0) أيقونات
الأنشطة المرتبطة
The Brown Dwarf builder's guide
astroEDU educational activity (links to astroEDU website) Description: Make your own model of a failed star!
License: CC-BY-4.0 المشاع الإبداعي نَسب المُصنَّف 4.0 دولي (CC BY 4.0) أيقونات
الفئات العمرية:
14-16
المرحلة التعليمية:
المرحلة الثانوية
مجالات التعلم:
يركز على الفنون الجميلة
, قائم على الملاحظة
, التعلم القائم على المشاريع
التكاليف:
تكلفة منخفضة
المدة:
3 ساعات
المهارات:
تحليل البيانات وتفسيرها
, توصيل المعلومات
, تطوير النماذج واستخدامها
