2025年10月27日
彗星莱蒙的双尾
影像提供: Massimo Penna
说明: 彗星莱蒙（Lemmon）有几条明亮的彗尾呢？答案是两条。在所展示的影像中，它似乎有三条，但为什么呢？原因是那条锯齿状的棕色丝状物是一条持续存在的流星痕，偶然地出现在遥远的彗星C/2025 A6（Lemmon）前方。流星痕是明亮流星在掠过后，残留在地球大气层中的热气体和细微尘埃，并在几秒内逐渐扩散。两条明亮的彗尾分别是横跨影像的蓝色离子尾，以及靠近左上方绿色彗发的白色尘尾。所有真正的彗尾都源自彗发内部的彗核。这张影像是几天前在意大利 曼恰诺Manciano拍摄的。本周，从美国中北部地区，彗星莱蒙将在日落后的西北天空中隐约可见。
明日的图片: bat sign
Due to the lapse in federal government funding, NASA is not updating APOD website. We sincerely regret this inconvenience.
由于美国联邦政府资金中断，NASA目前暂停更新APOD网站。对此带来的不便，我们深感抱歉。
英文原文:
Explanation: How many bright tails does Comet Lemmon have? Two. In the featured image it appears to have three, but why? The reason is that the zigzagging brown filament is a persistent meteor train that by luck appeared in front of the distant comet C/2025 A6 (Lemmon) . A meteor train is the hot gas and fine dust that remains in the Earth’s atmosphere and disperses in the seconds after a bright meteor flashes by. The two bright tails are the blue ion tail stretching across the image, and the white dust tail nearer the green coma on the upper left. All real comet tails originate from the nucleus of the comet inside the coma. The image was captured a few days ago from Manciano , Italy . This week, from mid-northern locations, Comet Lemmon will remain faintly visible in the northwest sky after sunset.
