四千颗系外行星

2019 July 10

4000 Exoplanets
Video Credit: SYSTEM Sounds (M. Russo, A. Santaguida); Data: NASA Exoplanet Archive

Explanation: Over 4000 planets are now known to exist outside our Solar System. Known as exoplanets, this milestone was passed last month, as recorded by NASA’s Exoplanet Archive. The featured video highlights these exoplanets in sound and light, starting chronologically from the first confirmed detection in 1992. The entire night sky is first shown compressed with the central band of our Milky Way Galaxy making a giant U. Exoplanets detected by slight jiggles in their parents-star’s colors (radial velocity) appear in pink, while those detected by slight dips in their parent star’s brightness (transit) are shown in purple. Further, those exoplanets imaged directly appear in orange, while those detected by gravitationally magnifying the light of a background star (microlensing) are shown in green. The faster a planet orbits its parent star, the higher the accompanying tone played. The retired Kepler satellite has discovered about half of these first 4000 exoplanets in just one region of the sky, while the new TESS mission is on track to find even more, all over the sky, orbiting the brightest nearby stars. Finding exoplanets not only helps humanity to better understand the potential prevalence of life elsewhere in the universe, but also how our Earth and Solar System were formed.

四千颗系外行星
影像来源: SYSTEM Sounds (M. Russo, A. Santaguida); Data: NASA Exoplanet Archive

说明：目前已知有超过4000颗行星存在于我们太阳系之外。根据美国航天局系外行星资料库的记录，这个里程碑在上个月就已经达成了。从1992年第一次已确认的探测开始，这段精彩的视频按照年代顺序、以声和光的方式呈现了这些系外行星。该视频首先呈现了经过压缩的整片夜空，我们银河系的中心带形成了一个巨大的U型结构。由测量母星色泽的轻微抖动（径向速度）所检测到的系外行星呈现出粉红色，而由测量母星亮度（凌星）的轻微下降所检测到的系外行星呈现出紫色。另外，通过成像直接发现的这些系外行星呈现出橙色，而那些通过引力放大背景恒星（微引力透镜）辉光所检测到的系外星系则呈现出绿色。行星绕其母星运行得越快，伴随的音调就越高。这颗已退役的开普勒卫星在天空的一片区域里发现了这4000颗系外行星的一半，而新的凌星系外行星巡天望远镜（TESS）计划正在天空中寻找更多围绕着附近最亮恒星运行的系外行星。寻找系外行星不仅有助于人类更好地了解宇宙中其它地方生命的潜在普遍性，而且还有助于了解我们的地球和太阳系是如何形成的。