火焰星云之内

2019 November 2

Inside the Flame Nebula
Image Credit & Copyright: Optical: DSS; Infrared: NASA/JPL-Caltech;
X-ray: NASA/CXC/PSU/ K.Getman, E.Feigelson, M.Kuhn & the MYStIX team

Explanation: The Flame Nebula stands out in this optical image of the dusty, crowded star forming regions toward Orion’s belt, a mere 1,400 light-years away. X-ray data from the Chandra Observatory and infrared images from the Spitzer Space Telescope can take you inside the glowing gas and obscuring dust clouds though. Swiping your cursor (or clicking the image) will reveal many stars of the recently formed, embedded cluster NGC 2024, ranging in age from 200,000 years to 1.5 million years young. The X-ray/infrared composite image overlay spans about 15 light-years across the Flame’s center. The X-ray/infrared data also indicate that the youngest stars are concentrated near the middle of the Flame Nebula cluster. That’s the opposite of the simplest models of star formation for the stellar nursery that predict star formation begins in the denser center of a molecular cloud core. The result requires a more complex model; perhaps star formation continues longer in the center, or older stars are ejected from the center due to subcluster mergers.

火焰星云之内
影像提供与版权: Optical: DSS; Infrared: NASA/JPL-Caltech;
X-ray: NASA/CXC/PSU/ K.Getman, E.Feigelson, M.Kuhn & the MYStIX team

说明: 在这幅到处都是恒星形成区的猎人腰带方向可见光影像里，1,400光年远的火焰星云 (NGC 2024)是其中相当醒目的天体。钱卓拉天文卫星的X射线数据和史匹哲太空望远镜的红外光影像，让我们得以一窥这些辉光云气和不透光尘埃云后方的景观。把鼠标移到(或点选)这幅影像上头，就能见到许多深藏在NGC 2024之内，刚在二十万年前至一百五十万年前诞生的成团恒星。这张由X射线与红外光数据组合而成的影像，涵盖了火焰星云中心约15光年的区域。与描述恒星形成区内恒星如何形成之极简模型大异其趣的是，X射线与红外光数据显示年轻恒星集中在星团的核心，而非极简模型预言的：恒星诞生起始于分子云较致密的核心(，然后渐次向边缘扩展)。这项成果显示我们需要较复杂的恒星形成模型，或许星云核心的恒星形成活动持续续较久，或者在次星团合并时，同时把较老的恒星从中心驱逐出去。