螺旋星系NGC 1512：内环
(原标题: Spiral Galaxy NGC 1512: The Inner Rings)
2022-05-08
浏览次数: 12
大多数星系都没有环——为什么这个星系有两个环？首先，ngc1512中心附近的明亮带是一个核环，这个环围绕着星系中心，发光的是新形成的恒星。然而，大多数恒星及其伴生的气体和尘埃，在更远的地方围绕银河系中心运行——这里是在图像边缘附近看到的。与直觉相反，这个环被称为内环。如果你仔细观察，你会看到这个内环连接着一个漫射的中央棒的两端，它水平地穿过星系。这些环状结构被认为是ngc1512自身在长期演化过程中的不对称性造成的。这些不对称星系的引力，包括恒星的条形，导致气体和尘埃从内环落到核环上，提高了这个环的恒星形成速度。一些螺旋星系也有第三个环——一个环绕星系更远的外环。
查看原文解释
Most galaxies don't have any rings -- why does this galaxy have two? To begin, the bright band near NGC 1512's center is a nuclear ring, a ring that surrounds the galaxy center and glows brightly with recently formed stars. Most stars and accompanying gas and dust, however, orbit the galactic center in a ring much further out -- here seen near the image edge. This ring is called, counter-intuitively, the inner ring. If you look closely, you will see this the inner ring connects ends of a diffuse central bar that runs horizontally across the galaxy. These ring structures are thought to be caused by NGC 1512's own asymmetries in a drawn-out process called secular evolution. The gravity of these galaxy asymmetries, including the bar of stars, cause gas and dust to fall from the inner ring to the nuclear ring, enhancing this ring's rate of star formation. Some spiral galaxies also have a third ring -- an outer ring that circles the galaxy even further out.