Rho Ophiuchi <彩色雲>

The Colorful Clouds of Rho Ophiuchi

影像版權與提供: Jim Misti and Steve Mazlin, (acquisition), Robert Gendler
(processing)

Explanation:
This stunning mosiac of the sky around bright stars Antares (Alpha Scorpii) and Rho Ophiuchi reveals spectacular colors in a cosmic starscape.
Near the top, Rho Ophiuchi and nearby stars are immersed in blue reflection nebulae - dust clouds that shine primarily by reflected starlight.
Cool supergiant star Antares (lower left) is itself shedding the material that reflects the evolved star's yellowish hue.
Characteristic of star forming regions, the telltale red emission from hydrogen gas also permeates the view along with dark, obscuring dust clouds seen in silhouette against the background stars and brighter nebulosities.
About 500 light-years away, the Rho Ophiuchi star clouds, are well in front of the nearby globular star cluster M4, visible just below and right of center.
The wide view spans about 6 degrees on the sky.

說明:
這張美麗的 星空包含心宿二(Antares)或稱為天蠍座α星 (AlphaScorpii)，以及蛇夫座Rho星(Rho Ophiuchi)，顯示星星多采多姿的顏色。
蛇夫座Rho星，位於上緣，像是埋在藍色的反射星雲裡，主要是來自於星塵反射星星的光。
心宿二是一顆比起一般星溫度低的超巨星(supergiant star)，在左下角，周圍的物質隱隱約約反射星星的黃色暈光。
中間偏右的星星形成的區域(star forming regions)，最大的特性就是呈現淡紅色的發光，是來自於氫氣，從因為受到星塵雲遮擋的陰影間蔓延開來。
蛇夫座Rho星的雲氣，大約500光年遠，正好在附近球狀星團(M4)的前方，就在圖中的下面的中間部位。
整個星場約有2度，約4個月亮的大小。

資料來源：Scientific American
　　　　　Department of Physics, NCKU