星系NGC 2525的超新星

2020年10月23日

Supernova in NGC 2525
Image Credit: NASA, ESA, A. Riess (STScI/JHU) and the SH0ES team
Acknowledgment: M. Zamani (ESA/Hubble)

Explanation: Big, beautiful, barred spiral galaxy NGC 2525 lies 70 million light-years from the Milky Way. It shines in Earth’s night sky within the boundaries of the southern constellation Puppis. About 60,000 light-years across, its spiral arms lined with dark dust clouds, massive blue stars, and pinkish starforming regions wind through this gorgeous Hubble Space Telescope snapshot. Spotted on the outskirts of NGC 2525 in January 2018, supernova SN 2018gv is the brightest star in the frame at the lower left. In time-lapse, a year long series of Hubble observations followed the stellar explosion, the nuclear detonation of a white dwarf star triggered by accreting material from a companion star, as it slowly faded from view. Identified as a Type Ia supernova, its brightness is considered a cosmic standard candle. Type Ia supernovae are used to measure distances to galaxies and determine the expansion rate of the Universe.

Tomorrow’s picture: light-weekend

星系NGC 2525的超新星
影像提供: NASA, ESA, A. Riess (STScI/JHU) and the SH0ES team
志谢: M. Zamani (ESA/Hubble)

说明: 位在南天船尾座方向的庞大美丽棒旋星系NGC 2525，离银河系约7千万光年远。在这幅壮丽的哈伯太空望远镜影像里，这个宽约60,000光年的星系之蜿蜒螺旋臂上，分布着黝黑的星云、大质量的泛蓝恒星、和粉红色的恒星形成区。而于视野左下角，还有位在NGC 2525外围，以最明亮恒星之姿现身，发现于2018年1月的超新星SN 2018gv。哈伯望远镜用一年的时间，对这例恒星爆炸进行一系列的观测，以追踪一颗白矮星因吸积伴星物质而触发的核爆事件，其亮度如何随时间演变，成果可见参这部缩时影片。这种Ia型超新星，其亮度咸认为宇宙的标准烛光。因此，Ia型超新星可用来测量星系的距离和宇宙的膨胀速率。

明日的图片: light-weekend