From Nature, 12 January 2022
Star formation near the Sun is driven by expansion of the Local Bubble
Star formation near the Sun is driven by the expansion of local bubbles
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.
For decades, we've known that the Sun is inside a local bubble, a cavity of low-density, high-temperature plasma surrounded by a layer of cold, neutral gas and dust. However, the precise shape and extent of this shell, the dynamics and timescales of its formation, and its relationship to nearby star formation remain uncertain, largely due to low-resolution models of the local interstellar medium. In this paper, we use new spatial and dynamic constraints to analyze the three-dimensional position, shape, and motion of dense gas and young stars within 200 parsecs from the Sun. We found that almost all of the star-forming complexes near the Sun are located on the surface of local bubbles, and their young stars expand primarily outward, perpendicular to the surface of the bubbles. The retrospective of the movements of these young stars supports the claim that the origin of the local bubbles was an explosion of star birth and death (supernova) that had previously occurred near the center of the bubble around 14 milliels. The expansion of local bubbles produced by supernovae swept the surrounding interstellar medium into an extended shell that had now broken and collapsed into the most prominent molecular cloud nearby, which in turn provided strong observational support for the supernova-driven theory of star formation.
Sentence by sentence comparison
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.
For decades, we've known that the Sun is inside a local bubble, a cavity of low-density, high-temperature plasma surrounded by a layer of cold, neutral gas and dust.
| cavity n. a hole or empty space inside sth solid 洞；孔；窟窿；腔 Plasma plasma neutral |
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.
However, the precise shape and extent of this shell, the dynamics and timescales of its formation, and its relationship to nearby star formation remain uncertain, largely due to low-resolution models of the local interstellar medium.
| impetus : the force or energy with which sth moves momentum; dynamics; inertia interstellar adj. between the stars in the sky 星际的 |
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.
In this paper, we use new spatial and dynamic constraints to analyze the three-dimensional position, shape, and motion of dense gas and young stars within 200 parsecs from the Sun.
| pc: parsec parsec (3.26 light-years) 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.
We found that almost all of the star-forming complexes near the Sun are located on the surface of local bubbles, and their young stars expand primarily outward, perpendicular to the surface of the bubbles.
| vicinity : a surrounding or nearby region 附近 perpendicular adj. vertical |
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 retrospective of the movements of these young stars supports the claim that the origin of local bubbles was the explosion of star birth and death (supernova) that occurred near the center of the bubble about 14 million years ago.
| Supernovae Supernova |
Supernova explosion