北極星北極星和周圍的塵埃
North Star: Polaris and Surrounding Dust
來源：Davide Coverta｜發表日期：2025-01-14
北極星為什麼被稱為北極星？首先，北極星是距離地球北自轉軸最近的亮星。 因此，當地球轉動時，星星看起來會圍繞北極星旋轉，但北極星本身卻始終保持在同一偏北方向--這就使北極星成為了北極星。 由於沒有明亮的恆星靠近地球的南自轉軸，所以目前也沒有明亮的南極星。 幾千年前，地球自轉軸的指向略有不同，因此織女星是北極星。 雖然北極星不是天空中最亮的星星，但它的位置很容易找到，因為它幾乎與北斗七星杯中的兩顆星星對齊。北極星靠近五度寬的特寫影像的中心，這是由數百次曝光合成的數字影像，使整個畫面都呈現出綜合通量星雲（IFN）的微弱氣體和塵埃。後發射手座北極星的表面會發生緩慢的脈動，導致這顆著名的恆星在幾天內亮度會發生百分之幾的變化。 今天紐約業餘天文學家協會主辦的變焦 APOD 講座
原文：Why is Polaris called the North Star? First, Polaris is the nearest bright star toward the north spin axis of the Earth. Therefore, as the Earth turns, stars appear to revolve around Polaris, but Polaris itself always stays in the same northerly direction -- making it the North Star. Since no bright star is near the south spin axis of the Earth, there is currently no bright South Star. Thousands of years ago, Earth's spin axis pointed in a slightly different direction so that Vega was the North Star. Although Polaris is not the brightest star on the sky, it is easily located because it is nearly aligned with two stars in the cup of the Big Dipper. Polaris is near the center of the five-degree wide featured image, a digital composite of hundreds of exposures that brings out faint gas and dust of the Integrated Flux Nebula (IFN) all over the frame. The surface of Cepheid Polaris slowly pulsates, causing the famous star to change its brightness by a few percent over the course of a few days. Today: Zoom APOD Lecture hosted by the Amateur Astronomers of Association of New York
※ 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！
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