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Glossary term: 變星

Description: 變星是指對觀測者而言亮度隨時間發生明顯變化的恆星。實際上,由於恆星的演化,所有恆星的亮度都會在數百萬年或數十億年內發生變化。而變星一詞通常是指那些發生亮度變化的時間尺度遠遠短於其演化時標的恆星。

產生光變有幾種可能的物理機制。有些恆星,如仙王座變星或天琴座RR型變星,它們是不穩定的,且會發生脈動,使得其大小和亮度發生變化。

其他恆星會噴射出明亮的物質,從而增加觀測到的總體亮度("爆發變星")。有一類被稱為災變變星或新星的恆星,它們的亮度會突然增加,然後又恢復到以前的水平。這類系統通常由一對恆星組成,其中一顆恆星的物質流向另一顆恆星,一旦達到某個臨界點,就會發生核聚變反應。其中一個伴星或另一個伴星發生大爆炸並變亮。

還有一些恆星看起來變化是因為它們在旋轉,交替地向我們展示亮度較高和亮度較低的一面,或者是由於雙星系統繞著彼此運行,其中一顆恆星週期性地被另一顆遮擋。後一類雙星被稱為食雙星。

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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

This is an automated transliteration of the simplified Chinese translation of this term

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".

Related Diagrams


獵戶座呈沙漏狀,兩串恆星分別向東北和西北方延伸

獵戶座星圖

Caption: 獵戶座及其明亮的恆星和周圍的星座。獵戶座被金牛座、波江座、天兔座、麒麟座和雙子座環繞(從上往下順時針依次排列)。獵戶座最亮的恆星參宿四和參宿七分別位於星座的北端(圖中上部)和南端(圖中下部),中間是著名的三星 "腰帶"。 獵戶座橫跨天赤道,因此在一年中的某些時候,從地球上的任何地方都能看到它。在世界上最北極或最南極地區,可能看不到獵戶座的某些部分。獵戶座在北半球冬季和南半球夏季的晚上最為明顯。獵戶座上方的藍線標誌著黃道,即太陽在一年中劃過天空的軌跡。太陽從不經過獵戶座,但人們偶爾會在獵戶座發現太陽系的其他行星和月球。 在獵戶座腰帶的正南方,有兩個梅西葉天體M42(獵戶座星雲)和M43,用綠色方框標出。這些星雲和M78(腰帶左邊的綠色方框)是巨大的獵戶座分子雲團的一部分。它覆蓋了獵戶座的大部分區域,包括這些分子雲正在坍縮形成新星的區域。 該圖的 y 軸表示赤緯,單位為度數,以北為上,x 軸表示赤經,單位為小時,以東為左。這裡標注的恆星大小與恆星的視星等有關,視星等是衡量恆星視亮度的標準。較大的點代表較亮的恆星。希臘字母表示星座中的亮星。這些恆星按亮度排序,最亮的恆星被標記為α星,第二亮的為β星,等等,不過並不總是完全遵循這種排序。圍繞著參宿四的圓圈表示它是一顆變星。虛線是國際天文學聯合會劃定的星座邊界,綠色實線是表示星座的常用形式之一。星座邊界和連接恆星的線條都不會出現在實際天空中。
Credit: 由國際天文學聯合會天文教育辦公室根據國際天文學聯合會/《天空與望遠鏡》的原文改編

License: CC-BY-4.0 Creative Commons 姓名標示 4.0 國際 (CC BY 4.0) icons


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

Caption: 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 and 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. Neither the constellation boundaries, nor the lines joining the stars appear on the sky. The blue line marks the ecliptic, the path the Sun appears to travel across the sky over the course of one year.
Credit: Adapted by the IAU Office of Astronomy for Education from the original by IAU/Sky & Telescope

License: CC-BY-4.0 Creative Commons 姓名標示 4.0 國際 (CC BY 4.0) icons