Planetary nebula Abell 78 stands out in this colorful telescopic skyscape. In fact the colors of the spiky Milky Way stars depend on their surface temperatures, both cooler (yellowish) and hotter (bluish) than the Sun. But Abell 78 shines by the characteristic emission of ionized atoms in the tenuous shroud of material shrugged off from an intensely hot central star.
行星狀星雲Abell 78佔據了這張望遠鏡彩色照片的中心位置。圖中閃耀著光芒的銀河系恆星的顏色取決於它們的表面溫度,黃色的比太陽溫度低。而藍色的則比太陽熱。Abell 78的輝光,出自從熾熱的中心恆星拋出的物質薄層中電離原子的特徵發射。
The atoms are ionized, their electrons stripped away, by the central star's energetic but otherwise invisible ultraviolet light. The visible blue-green glow of loops and filaments in the nebula's central region corresponds to emission from doubly ionized oxygen atoms, surrounded by strong red emission from ionized hydrogen.
行星狀星雲Abell 78佔據了這張望遠鏡彩色照片的中心位置。圖中閃耀著光芒的銀河系恆星的顏色取決於它們的表面溫度,黃色的比太陽溫度低。而藍色的則比太陽熱。Abell 78的輝光,出自從熾熱的中心恆星拋出的物質薄層中電離原子的特徵發射。在中心恆星高能紫外線的作用下,這些原子被電離,裡面的電子被剝離出去。在星雲中央區域的藍綠色環狀和羽狀輝光是二次電離的氧原子發射出來的;周圍則是電離氫較強的紅色輻射。
Some 5,000 light-years distant toward the constellation Cygnus, Abell 78 is about three light-years across. A planetary nebula like Abell 78 represents a very brief final phase in stellar evolution that our own Sun will experience ... in about 5 billion years.
Abell 78星雲位於天鵝座中,距離5,000光年,大小約3光年。像Abell 78這樣的行星狀星雲代表著恆星演化的一個短暫的終末階段,我們的太陽將在50億年後經歷這樣的過程。