Astronomy Picture of the Day

Explanation: The Hubble Double Bubble Planetary Nebula is bubbling over with excitement. More mundanely known as Hubble 5, this bipolar planetary nebula is being created by a hot wind of particles streaming away from the central star system. The hot gas expands into the surrounding interstellar medium in a fashion similar to the inflation of hot air balloons. A supersonic shock-wave can form at the boundary, causing newly excited gas there to shine as electrons recombine with resident elements. In the above picture, colors are assigned according to the energy of the recombinant radiation. This star system lies about 2200 light-years from Earth, and likely includes a Sun-like star slowly transforming itself into a white dwarf.

哈伯雙泡行星狀星雲是個有趣度爆表的天體。 這個雙瓣行星狀星雲名為哈伯5號，是由中心母星噴出的熾熱粒子風所創造出來的。 這些熾熱氣體以類似填充熱氣球的方式，造成到周圍星際物質的膨脹。 當超音速激波形成於粒子風和星際物質的邊界時，會激發並電離雲氣，而電子與周圍的電離元素復合時會發光。 在上圖裡，色彩是根據復合輻射的能量配色。 這個恆星系統離地球約2200光年遠，其類太陽主星很可能正緩緩轉變成白矮星。