Glossary term: 超巨星
Description: 超巨星是體積最大、亮度最高的恆星。它們可能比太陽大幾百倍，比太陽亮幾千倍。它們占據赫茲普朗-拉塞爾圖的頂部區域，絕對目視星等在-3 到-8 之間。超巨星的溫度範圍從大約3400開爾文（K）到超過20000開爾文（K）不等，它們要麼是大質量恆星，要麼處於恆星演化的後期階段。超巨星可以根據它們的光譜來識別，超巨星可以通過它們的光譜來識別，其特徵譜線對高亮度和低表面重力敏感：這些光譜線與較小恆星的線寬相比是較窄的。超巨星的典型例子包括獵戶座的參宿四和造父變星。
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See this term in other languages
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
This is an automated transliteration of the simplified Chinese translation of this term
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In Other Languages
- 阿拉伯語: نجم فائق الضخامة
- 德語: Überriesen
- 英語: Supergiant Star
- 西班牙語: Estrella supergigante
- 波斯語: ستاره ابرغول
- 法語: Étoile supergéante
- 義大利語: Stella supergigante
- 日語: 超巨星 (external link)
- 韓語: 초거성
- 巴西葡萄牙語: Estrela supergigante
- 簡體中文: 超巨星
Related Media
The red supergiant Betelgeuse
Caption: The image shows Betelgeuse, a red supergiant in the constellation Orion, observed by the Atacama Large Millimeter/submillimeter Array (ALMA). ALMA consists of many antennae spread across a plain in Northern Chile. The observations from all of these receivers is synthesised together by a central computer to form an image. The wide distances between the antennae mean that is can resolve very fine details.
Most stars we observe are just seen as points of light, but Betelgeuse is so large (with a radius about 1,400 times larger than the Sun) and is sufficiently nearby that it is one of the few stars to have been resolved to show it as an extended object.
Betelgeuse is a massive star, more than 14 times the mass of the Sun and is relatively young for a star (less than 14 million years old). However, its high mass led to it having a very hot core which burned through its hydrogen fuel quickly. It has since evolved through many stages and now appears as a red supergiant, it's final stage before exploding as a supernova. When such an explosion will happen is not known for certain, but it could be in around 100,000 years. Such an explosion would be visible from Earth, even during the day.
Credit: ALMA (ESO/NAOJ/NRAO)/E. O’Gorman/P. Kervella
credit link
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Related Diagrams
赫羅圖
Caption: 這張圖展示了不同恆星溫度和亮度。每個點的大小代表恆星的半徑，顏色代表人眼所看到的顏色。恆星的顏色從淡藍色到淡橙紅色不等，沒有恆星具有像紅、綠或藍這樣的純顏色，因為恆星的光譜包含了許多不同顏色的光。然而，最紅的恆星通常被稱為紅恆星，最藍的恆星被稱為藍恆星。為了展示不同類型的恆星，製作這個圖表的恆星樣本選擇上並沒有反映出每種類型恆星的實際數量比例。
從左上到右下是一條長長的恆星帶，這些恆星在其核心燃燒氫氣，這被稱為主序。在這條線上，我們可以看到參宿三（Mintaka）、波江座α星（Achernar）、天狼星A（Sirius A）、太陽和比鄰星（Proxima Centauri）等恆星。在主序線右下方的比鄰星週圍的天體被稱為紅矮星。在紅矮星的右下方是Teide 1和Kelu-1 A。這兩個天體是褐矮星，它們的質量太低，核心沒有足夠的熱量來持續地進行氫融合。由於它們不燃燒氫，褐矮星不被認為是主序星。"褐矮星"這個名字與它們的顏色無關。
在主序星的上方，我們發現次巨星、巨星和超巨星。這些是已經完成了核心的氫燃燒並演化成更大天體的恆星。恆星的亮度取決於其溫度和大小，因此巨星比具有較小半徑但相同溫度的恆星更亮。隨著時間的推移，這些天體將走向生命的盡頭，經歷行星狀星雲階段或變成超新星。以行星狀星雲階段結束生命的恆星會形成一種叫做白矮星的恆星殘骸。這種天體比相同溫度的恆星小得多，因此更暗淡，並且位於主序星帶的顯著下方。以超新星結束生命的恆星會成為黑洞或中子星。這些在這個圖表上沒有顯示。
Credit: IAU OAE/Niall Deacon
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Stellar Evolution
Caption: This diagram shows the life cycle of stars of different masses. The mass of the different types of star increases from bottom to top with time going from left to right.
The life cycle of a star depends on its mass, with lower mass stars have longer lifetimes. All stars form from clouds of gas that collapse under their own gravity. As the star collapses, its core becomes hotter and denser. If the star has a mass greater than 0.08 solar masses (0.08 times the mass of the Sun), the pressure of the star’s mass pushing down on its core creates a high enough core temperature for hydrogen fusion to ignite. This burns hydrogen into helium in the star’s core, providing a heat source to power the star and to stop its core from collapsing further. If the collapsing object has a mass below 0.08 solar masses then it does not ignite hydrogen fusion in its core. It continues to cool and slowly contract. Such substellar objects are known as brown dwarfs, shown here in the lowest row.
After stars have formed, they burn hydrogen in their cores and begin their so-called main sequence phase. The most massive stars (>25 solar masses, shown here at the top) have very high core temperatures and thus burn through their hydrogen fuel more quickly. This means they may only spend a few million years on the main sequence burning hydrogen in their cores. Once the hydrogen in the core is exhausted the star’s core contracts, becomes hotter and helium burning starts in the core. While the core contracts, the outer layers of the star expand and it becomes a supergiant. For the most massive stars strong stellar winds strip off the cooler outer layers, leading to the star being very large and very hot, a blue supergiant. Once helium is exhausted in the core, carbon is burned, and then heavier elements. Eventually the star ends with an iron core. Fusing iron into heavier elements does not generate energy so at this point fusion stops in the core. Once this core of iron is massive enough, it and the surrounding matter suddenly collapses to form a black hole and the outer layers are flung off in a supernova explosion.
Slightly lower mass stars (between 8 and 25 solar masses, seen here second top) evolve in a similar way although they do not have strong enough winds to push their outer layers away and become blue supergiants, instead it evolves into a red supergiant. While such stars also collapse and create supernova explosions. The remnant of the star’s core is not massive enough to collapse into a black hole. Instead, its electrons and protons combine to form neutrons and it is supported by a quantum mechanical effect called neutron degeneracy pressure. This results in the remnant of the star being a tiny neutron star, several solar masses in mass but only a few kilometres across.
For stars similar in mass to the Sun (between 0.4 and 8 solar masses, seen here in the middle row), the star burns hydrogen in its core until the hydrogen in its core is exhausted. At this point a hydrogen burning shell forms around the core. Eventually the core will become hot enough to burn helium into carbon and oxygen. After this the star is left with a carbon and oxygen core surrounded by shells burning helium and hydrogen. These shells are unstable producing thermal pulsations that convulse the star. Eventually these pulsations become so extreme that the star’s outer layers are thrown off. This leaves the carbon and oxygen core as a white dwarf supported by electron degeneracy pressure. The outer layers of the star form what is known as a planetary nebula (which doesn’t actually have anything to do with planets despite the name).
The lowest mass stars (seen here in the second bottom row) are so low in mass that their evolutionary timescales are much longer than the age of the universe. This means that none have evolved beyond the main-sequence. Low mass stars are fully convective meaning material in the core is constantly being mixed with material above. This means that all the hydrogen in the star would eventually be burned in the core, but this will take trillions of years.
Credit: Danielle Futselaar/IAU OAE
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