Astronomy Picture of the Day——南天的蟹状星云
The Shape of the Southern Crab
Image Credit: NASA, ESA, STScI
Explanation: The symmetric, multi-leggedappearance of the Southern Crab Nebula is certainly distinctive. About 7,000light-years distant toward the southern sky constellation Centaurus, itsglowing nested hourglass shapes are produced by the remarkable symbiotic binarystar system at its center. The nebula's dramatic stellar duo consists of a hotwhite dwarf star and cool, pulsating red giant star shedding outer layers thatfall onto the smaller, much hotter companion. Embedded in a disk of material,outbursts from the white dwarf cause an outflow of gas driven away both aboveand below the disk resulting in the bipolar hourglass shapes. The brightcentral shape is about half a light-year across. This new Hubble Space Telescopeimage celebrates the 29th anniversary of Hubble's launch on April 24, 1990 onboard the Space Shuttle Discovery.
南天的蟹状星云
南天蟹状星云轴对称且多足的外观确实与众不同。它位于南天半人马座方向，距离地球约7000光年，其炽热的沙漏形状是由位于中心、壮观的共生双星系统组成的。这里引人注目的双星是由一颗炽热的白矮星和一颗低温的脉动红巨星组成，而红巨星脱落的物质则落到更小的伴星上。内嵌在物质盘中的白矮星的爆炸导致外流气体从盘面上方和下方流出，形成了双极的沙漏形状。明亮的中央形状跨度约为半个光年。这幅刚发布不久的图像是为纪念哈勃太空望远镜在1990年4月24日搭载于发现号航天飞机发射升空29周年。
参考文献：
https://apod.nasa.gov/apod/image/1904/SouthernCrabHST_2100x2460.jpg
近期文章：
Astronomy Picture of the Day——拉帕尔马上空的流星、彗星和北斗七星