Arp 78: 白羊座的特殊星系

2023年2月23日

Arp 78: Peculiar Galaxy in Aries
Image Credit & Copyright: Josep Drudis

Explanation: Peculiar spiral galaxy Arp 78 is found within the boundaries of the head strong constellation Aries. Some 100 million light-years beyond the stars and nebulae of our Milky Way galaxy, the island universe is an enormous 200,000 light-years across. Also known as NGC 772, it sports a prominent, outer spiral arm in this detailed cosmic portrait. Tracking along sweeping dust lanes and lined with young blue star clusters, Arp 78’s overdeveloped spiral arm is pumped-up by galactic-scale gravitational tides. Interactions with its brightest companion galaxy, the more compact NGC 770 seen above and right of the larger spiral, are likely responsible. Embedded in faint star streams revealed in the deep telescopic exposure, NGC 770’s fuzzy, elliptical appearance contrasts nicely with spiky foreground Milky Way stars in matching yellowish hues.

Tomorrow’s picture: beyond Jones-Emberson 1

Arp 78: 白羊座的特殊星系
图像提供与版权: Josep Drudis

说明: 特殊螺旋星系Arp 78座落在意志坚定的白羊座之内。位于我们银河系恒星和星云后方约1亿光年远处的这个宇宙岛，极为庞大、跨幅超过200,000光年。在这幅细致清晰的宇宙图像里，亦名为NGC 772的此星系，曳着鲜明的外螺旋臂。上头散列着宽广尘埃带及年轻泛蓝星团的星系Arp 78之过度发展螺旋臂，可能是由星系级重力潮汐作用所激发。而造就这些现象的天体，则可能是位在外螺旋臂右上方，较紧实的明亮伴星系NGC 770。除此之外，这幅望远镜深空图像里的NGC 770，其嵌在暗淡恒星流内的模糊椭圆身影，与同是黄色调、带芒的银河系前景恒星形成鲜明的对比。

明日的图片: beyond Jones-Emberson 1