NASA·APOD每日天文一图2022.5.23 [超高清]

This picture of Andromeda shows not only where stars are now, but where stars will soon be. Of course, the big, beautiful Andromeda Galaxy, M31, is a spiral galaxy -- and a mere 2.5 million light-years away. Both space-based and ground-based observatories have been here combined to produce this intriguing composite image of Andromeda, at wavelengths both inside and outside normally visible light. The visible light shows where M31's stars are now -- as highlighted in white and blue hues and imaged by the Hubble, Subaru, and Mayall telescopes. The infrared light shows where M31's future stars will soon form -- as highlighted in orange hues and imaged by NASA's Spitzer Space Telescope. The infrared light tracks enormous lanes of dust, warmed by stars, sweeping along Andromeda's spiral arms. This dust is a tracer of the galaxy's vast interstellar gas -- the raw material for future star formation. These new stars will likely form over the next hundred million years, surely well before Andromeda merges with our Milky Way Galaxy in about 5 billion years. 

这张仙女座的照片不仅显示了恒星现在的位置，而且还显示了恒星即将出现的位置。当然，美丽的仙女座大星系M31是一个螺旋星系，距离我们只有250万光年。在这里，天基和地基观测站结合在一起，在正常可见光内外的波长上生成了这幅有趣的仙女座综合图像。可见光显示了M31恒星现在的位置，如哈勃、斯巴鲁和梅亚尔望远镜所拍摄的白色和蓝色高亮显示。红外光显示了M31未来恒星即将形成的位置，如NASA斯皮策太空望远镜拍摄到的橙色高亮显示。红外光沿着仙女座的旋臂，追踪着被恒星加热的巨大尘埃带。这些尘埃是银河系巨大星际气体的示踪剂，星际气体是未来恒星形成的原材料。这些新恒星很可能会在未来一亿年内形成，肯定会在大约50亿年后仙女座星系与银河系合并之前形成。