STEVE: 法国上空形如跨天长河的光弧

STEVE: 法国上空形如跨天长河的光弧

STEVE: A Glowing River over France
Credit & Copyright: Louis LEROUX-GÉRÉ

Explanation: Sometimes a river of hot gas flows over your head. In this case the river created a Strong Thermal Emission Velocity Enhancement (STEVE) that glowed bright red, white, and pink. Details of how STEVEs work remain a topic of research, but recent evidence holds that their glow results from a fast-moving river of hot ions flowing over a hundred kilometers up in the Earth’s atmosphere: the ionosphere. The more expansive dull red glow might be related to the flowing STEVE, but alternatively might be a Stable Auroral Red (SAR) arc, a more general heat-related glow. The featured picture, taken earlier this month in Côte d’Opale, France, is a wide-angle digital composite made as the STEVE arc formed nearly overhead. Although the apparition lasted only a few minutes, this was long enough for the quick-thinking astrophotographer to get in the picture — can you find him?

Tomorrow’s picture: webb stars

STEVE: 法国上空形如跨天长河的光弧
影像提供与版权: Louis LEROUX-GÉRÉ

说明: 有时候，河流状的高温气体会在头顶泛流。在上面这个例证里，这道气流造就了一例弧状的增速导致的突发性热辐射（STEVE），并散发出明亮的红、白和粉红辉光。STEVE形成机制的细节目前仍是研究的题材，但最新的证据显示，辉光的源头是地球大气在距离地表一百公里以上的电离层里快速流动的高温离子。不过，宽广的暗红辉光虽然可能与流动的STEVE有关，但也不排除是稳定极光红弧 (SAR)，另一种与热相关的较常见辉光。这幅宽视野的数位组合主题影像，是在本月稍早摄于法国的蛋白石海岸（Côte d’Opale），而拍照的当时STEVE光弧几乎悬在头顶。虽然这片光影只持续了数分钟，但对于这位反应迅速的天文摄影者来说，时间已足够让自己入镜；你能找到他吗？

明日的图片: webb stars