Very faint planetary nebula Abell 7 is some 1,800 light-years distant, just south of Orion in planet Earth's skies in the constellation Lepus, The Hare. Surrounded by Milky Way stars and near the line-of-sight to distant background galaxies, its generally simple spherical shape, about 8 light-years in diameter, is outlined in this deep telescopic image. Within its confines are beautiful, more complex details enhanced by the use of narrowband filters. Emission from hydrogen is shown in reddish hues with oxygen emission mapped to green and blue colors, giving Abell 7 a natural appearance that would otherwise be much too faint to be appreciated by eye. A planetary nebula represents a very brief final phase in stellar evolution that our own Sun will experience 5 billion years hence, as the nebula's central, once sun-like star shrugs off its outer layers. Abell 7 itself is estimated to be 20,000 years old. Its central star is seen here as a fading white dwarf some 10 billion years old.?

非常暗淡的行星狀星云Abell 7距離我們大約1800光年遠，就在獵戶座以南，獵戶座位于兔子星座的地球天空中。在這張深度望遠鏡圖像中，它被銀河系恒星包圍，靠近遙遠背景星系的視線，通常是簡單的球形，直徑約8光年。在它的范圍內(nèi)是美麗的，更復雜的細節(jié)通過窄帶濾波器的使用而增強。氫的發(fā)射以微紅色顯示，而氧的發(fā)射則映射為綠色和藍色，這給了阿貝爾7一個自然的外觀，否則它會太微弱而無法被眼睛欣賞。行星狀星云代表了恒星演化的一個非常短暫的最后階段，我們自己的太陽將在50億年后經(jīng)歷這一階段，因為該星云的中心，曾經(jīng)類似太陽的恒星擺脫了外層。阿貝爾7號本身估計有20000年的歷史。它的中心恒星在這里被視為一顆大約100億年前正在衰退的白矮星。