兩個星雲的故事
A Tale of Two Nebulae
來源：Kent Biggs｜發表日期：2025-08-22
這幅色彩斑斕的天琴座望遠鏡觀測圖揭示了 M 57 （俗稱環狀星雲）的暗淡外暈和較明亮的中央環形區域。對於現代天文學家來說，M 57 是一個著名的行星狀星雲。M 57 的中心環直徑約為一光年，但它絕對不是行星，而是銀河系中一顆垂死的類太陽恆星的氣態籠罩物。左側的 IC 1296 是一個和 M 57 差不多大的棒旋星系，它更暗，也更容易被忽視。事實上，在 100 多年前，IC 1296 還被稱為螺旋星雲。偶然的機會，這兩個星系出現在同一個視野中，雖然它們看起來大小相似，但實際上卻相距甚遠。M 57 距離我們的銀河系只有 2000 光年。銀河系外的 IC 1296 （又名 PGC 62532 ）距離我們有 200 , 000 , 000 光年。這比 M 57 遠了大約 10 萬倍，但是由於它們看起來大小差不多，所以前螺旋星雲 IC 1296 也一定比行星狀星雲 M 57 大 10 萬倍。仔細觀察這張清晰的 21 世紀天體影像，你會發現畫面中還散佈著更多遙遠的背景星系。
原文：This colorful telescopic view towards the musical northern constellation Lyra reveals the faint outer halos and brighter central ring-shaped region of M57, popularly known as the Ring Nebula. To modern astronomers M57 is a well-known planetary nebula. With a central ring about one light-year across, M57 is definitely not a planet though, but the gaseous shroud of one of the Milky Way's dying sun-like stars. Roughly the same apparent size as M57, the fainter and more often overlooked barred spiral galaxy at the left is IC 1296. In fact, over 100 years ago IC 1296 would have been known as a spiral nebula. By chance the pair are in the same field of view, and while they appear to have similar sizes they are actually very far apart. At a distance of a mere 2,000 light-years M57 is well within our own Milky Way galaxy. Extragalactic IC 1296 (aka PGC62532) is more like 200,000,000 light-years distant. That's about 100,000 times farther away than M57 but since they appear roughly similar in size, former spiral nebula IC 1296 must also be about 100,000 times larger than planetary nebula M57. Look closely at the sharp 21st century astroimage to spot even more distant background galaxies scattered through the frame.
※ 本文由萌芽機器人自動轉貼自每日一天文圖（Astronomy Picture of the Day，APOD），原文為英文，正體中文是透過 DeepL 翻譯及 OpenCC 進行自動處理，內容僅供參考，若有任何錯誤之處還請見諒！
關於每日一天文圖：每日一天文圖網站是美國國家航空暨太空總署與密西根理工大學提供的服務，網站每天提供一張影像或圖片，並由天文學家撰寫扼要說明其特別之處。