仙后座上一颗明亮的新星
(原标题: A Bright Nova in Cassiopeia)
2021-06-07
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仙后座上的新亮点是什么？一颗新星。尽管新星在宇宙中经常发生，但这颗被称为nova Cas 2021或V1405 Cas的新星上个月在地球的天空中变得异常明亮，以至于肉眼可以看到它。新星Cas 2021在3月中旬首次变亮，但出乎意料的是，它在5月中旬变得更加明亮，并在大约一周的时间里保持相当明亮。随后，这颗新星又回到了5月初的水平，但现在又稍微变亮了，通过双筒望远镜仍然可以看到。根据箭头所示，这颗新星位于仙后座，离气泡星云不远。一颗新星通常是由一颗白矮星表面的热核爆炸引起的，这颗白矮星正在从一颗双星同伴那里吸积物质——尽管这种爆发的细节目前尚不清楚。新星不会摧毁底层恒星，有时还会再次出现。这幅特色图像是在美国密歇根州底特律市拍摄的14个小时的图像。专业和业余天文学家可能会继续监测新星Cas 2021，并对其成因的细节进行假设。
查看原文解释
What’s that new spot of light in Cassiopeia? A nova. Although novas occur frequently throughout the universe, this nova, known as Nova Cas 2021 or V1405 Cas, became so unusually bright in the skies of Earth last month that it was visible to the unaided eye. Nova Cas 2021 first brightened in mid-March but then, unexpectedly, became even brighter in mid-May and remained quite bright for about a week. The nova then faded back to early-May levels, but now is slightly brightening again and remains visible through binoculars. Identified by the arrow, the nova occurred toward the constellation of Cassiopeia, not far from the Bubble Nebula. A nova is typically caused by a thermonuclear explosion on the surface of a white dwarf star that is accreting matter from a binary-star companion -- although details of this outburst are currently unknown. Novas don't destroy the underlying star, and are sometimes seen to recur. The featured image was created from 14 hours of imaging from Detroit, Michigan, USA. Both professional and amateur astronomers will likely continue to monitor Nova Cas 2021 and hypothesize about details of its cause.
© Chuck Ayoub