mariah

When Roses Aren't Red



影像版權與提供: Jay Ballauer  

Explanation:
      Not all roses are red of course, but they can still be very pretty. Likewise, the beautiful Rosette Nebula and other star forming regions are often shown in astronomical images with a predominately red hue - in part because the dominant emission in the nebula is from hydrogen atoms. Hydrogen's strongest optical emission line, known as H-alpha, is in the red region of the spectrum, but the beauty of an emission nebula need not be appreciated in red light alone. Other atoms in the nebula are also excited by energetic starlight and produce narrow emission lines as well. In this gorgeous view of the Rosette's central regions, narrow band images are combined to show emission from sulfur atoms in red, hydrogen in blue, and oxygen in green. In fact, the scheme of mapping these narrow atomic emission lines into broader colors is adopted in many Hubble images of stellar nurseries. This image spans about 50 light-years in the constellation Monoceros, at the 3,000 light-year estimated distance of the Rosette Nebula.

說明:
      並不是所有的玫瑰都是紅色，但它們仍然非常美麗。 同樣地，美麗的 薔薇星雲(Rosette Nebula) 以及其他的星星形成區域，經常是利用紅色來顯示天文圖片，部分因為星雲主要的發光是來自於氫原子。 氫氣最強烈的可見光發光線，例如 H-alpha ，就是紅色，但不只這個顏色，星雲還有其他的原子，被高能的恆星風所激發的窄發光線。 這張薔薇星雲中心內部區域的影像，很多窄波的影像顯示發光線來自於硫原子(紅色)，氫氣(藍色)，以及氧氣(綠色)。 事實上，這樣以原子的發光窄線表示顏色方式，是很多哈伯太空望遠鏡所取色的方法。 這張影像在麒麟座(Monoceros)，橫跨約50光年， 估計 薔薇星雲 距離我們約 3,000 光年。

資料來源: Scientific American
               Department of Physics, NCKU