From Nature, 12 January 2022
Star formation near the Sun is driven by expansion of the Local Bubble
太陽附近的恒星形成是由局部氣泡的擴張驅動的
Catherine Zucker1,2 ✉, Alyssa A. Goodman1, João Alves3, Shmuel Bialy1,4, Michael Foley1,
Joshua S. Speagle5,6,7, Josefa Groβschedl3, Douglas P. Finkbeiner1,8, Andreas Burkert9,10,
Diana Khimey1 & Cameren Swiggum3,11
For decades we have known that the Sun lies within the Local Bubble, a cavity of low-density, high-temperature plasma surrounded by a shell of cold, neutral gas and dust. However, the precise shape and extent of this shell, the impetus and timescale for its formation, and its relationship to nearby star formation have remained uncertain, largely due to low-resolution models of the local interstellar medium. Here we report an analysis of the three-dimensional positions, shapes and motions of dense gas and young stars within 200 pc of the Sun, using new spatial and dynamical constraints. We find that nearly all of the star-forming complexes in the solar vicinity lie on the surface of the Local Bubble and that their young stars show outward expansion mainly perpendicular to the bubble’s surface. Tracebacks of these young stars’ motions support a picture in which the origin of the Local Bubble was a burst of stellar birth and then death (supernovae) taking place near the bubble’s centre beginning approximately 14 Myr ago. The expansion of the Local Bubble created by the supernovae swept up the ambient interstellar medium into an extended shell that has now fragmented and collapsed into the most prominent nearby molecular clouds, in turn providing robust observational support for the theory of supernova-driven star formation.
幾十年來，我們已經知道太陽位于局部氣泡内，局部氣泡是一個低密度、高溫等離子體的腔體，被一層冷的、中性的氣體和塵埃所包圍。然而，這個殼層的精确形狀和範圍，它形成的動力和時間尺度，以及它與附近恒星形成的關系仍然不确定，這主要是由于當地星際媒體的低分辨率模型。在本文中，我們利用新的空間和動力學限制，分析了距離太陽200秒差距内緻密氣體和年輕恒星的三維位置、形狀和運動。我們發現，太陽附近幾乎所有的恒星形成複合物都位于局部氣泡的表面，它們的年輕恒星主要向外擴張，垂直于氣泡的表面。對這些年輕恒星運動的追溯支援了這樣一種說法，即本地氣泡的起源是大約14密爾以前發生在氣泡中心附近的恒星誕生和死亡(超新星)的爆發。由超新星産生的局部氣泡的膨脹将周圍的星際媒體掃進了一個擴充的外殼，現在這個外殼已經破碎并坍縮成附近最顯著的分子雲，反過來為超新星驅動的恒星形成理論提供了有力的觀測支援。
逐句對照
For decades we have known that the Sun lies within the Local Bubble, a cavity of low-density, high-temperature plasma surrounded by a shell of cold, neutral gas and dust.
幾十年來，我們已經知道太陽位于局部氣泡内，局部氣泡是一個低密度、高溫等離子體的腔體，被一層冷的、中性的氣體和塵埃所包圍。
| cavity n. a hole or empty space inside sth solid 洞；孔；窟窿；腔 plasma 等離子體 neutral 中性的 |
However, the precise shape and extent of this shell, the impetus and timescale for its formation, and its relationship to nearby star formation have remained uncertain, largely due to low-resolution models of the local interstellar medium.
然而，這個殼層的精确形狀和範圍，它形成的動力和時間尺度，以及它與附近恒星形成的關系仍然不确定，這主要是由于當地星際媒體的低分辨率模型。
| impetus : the force or energy with which sth moves 動量；動力；慣性 interstellar adj. between the stars in the sky 星際的 |
Here we report an analysis of the three-dimensional positions, shapes and motions of dense gas and young stars within 200 pc of the Sun, using new spatial and dynamical constraints.
在本文中，我們利用新的空間和動力學限制，分析了距離太陽200秒差距内緻密氣體和年輕恒星的三維位置、形狀和運動。
| pc: parsec 秒差距(3.26光年) a unit of measure for interstellar space that is equal to 3.26 light-years. |
We find that nearly all of the star-forming complexes in the solar vicinity lie on the surface of the Local Bubble and that their young stars show outward expansion mainly perpendicular to the bubble’s surface.
我們發現，太陽附近幾乎所有的恒星形成複合物都位于局部氣泡的表面，它們的年輕恒星主要向外擴張，垂直于氣泡的表面。
| vicinity : a surrounding or nearby region 附近 perpendicular adj. 垂直的 |
Tracebacks of these young stars’ motions support a picture in which the origin of the Local Bubble was a burst of stellar birth and then death (supernovae) taking place near the bubble’s centre beginning approximately 14 Myr ago.
對這些年輕恒星運動的追溯支援了這樣一種說法，即本地氣泡的起源是大約1400萬年以前發生在氣泡中心附近的恒星誕生和死亡(超新星)的爆發。
| supernovae 超新星 |
超新星爆炸