2025年10月6日
彗星莱蒙的离子尾巴变化
影像提供与版权: Victor Sabet & Julien De Winter
说明: 彗星的尾巴如何变化？这取决于彗星的特性。C/2025 A6（彗星莱蒙）的离子尾一直在显著变化，正如这张从9月25日至10月3日在美国 德克萨斯州拍摄的五天序列图像（从左到右）所详述。在某些日子，彗星的离子尾比其他日子更为复杂。尾巴变化的原因包括物质的喷出速率、彗核的状态、太阳风的强度和复杂性，以及彗星的自转速度。有时，甚至因为地球观测角度的改变，会在一周内看到明显的差异。一般来说，彗星的离子尾会指向远离太阳的方向，因为气体被太阳风推动。彗星莱蒙仍在接近地球并变得更亮，将于10月21日最接近地球，并于11月8日最接近太阳。
明日的图片: supernova encore
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 does a comet tail change? It depends on the comet. The ion tail of Comet C/2025 A6 (Lemmon) has been changing markedly, as detailed in the featured image sequenced over five days between September 25 and October 3 (left to right) from Texas , USA . On some days, the comet’s ion tail was relatively more complex than other days. Reasons for tail changes include the rate of ejection of material from the comet’s nucleus , the strength and complexity of the passing solar wind , and the rotation rate of the comet . Sometimes, over the course of a week, apparent differences even result from a change of perspective from the Earth. In general, a comet’s ion tail will point away from the Sun , as gas expelled is pushed out by the Sun’s wind . Comet Lemmon is still inbound and brightening , passing nearest the Earth on October 21 and nearest the Su n on November 8.
