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1.
Nature ; 628(8006): 62-65, 2024 Apr.
Article En | MEDLINE | ID: mdl-38378142

Our Sun lies within 300 parsecs of the 2.7-kiloparsecs-long sinusoidal chain of dense gas clouds known as the Radcliffe Wave1. The structure's wave-like shape was discovered using three-dimensional dust mapping, but initial kinematic searches for oscillatory motion were inconclusive2-7. Here we present evidence that the Radcliffe Wave is oscillating through the Galactic plane while also drifting radially away from the Galactic Centre. We use measurements of line-of-sight velocity8 for 12CO and three-dimensional velocities of young stellar clusters to show that the most massive star-forming regions spatially associated with the Radcliffe Wave (including Orion, Cepheus, North America and Cygnus X) move as though they are part of an oscillating wave driven by the gravitational acceleration of the Galactic potential. By treating the Radcliffe Wave as a coherently oscillating structure, we can derive its motion independently of the local Galactic mass distribution, and directly measure local properties of the Galactic potential as well as the Sun's vertical oscillation period. In addition, the measured drift of the Radcliffe Wave radially outwards from the Galactic Centre suggests that the cluster whose supernovae ultimately created today's expanding Local Bubble9 may have been born in the Radcliffe Wave.

2.
Nature ; 601(7893): 334-337, 2022 01.
Article En | MEDLINE | ID: mdl-35022612

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 dust1-3. However, the precise shape and extent of this shell4,5, the impetus and timescale for its formation6,7, and its relationship to nearby star formation8 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 spatial9-11 and dynamical constraints12. 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.

3.
Nature ; 578(7794): 237-239, 2020 02.
Article En | MEDLINE | ID: mdl-31910431

For the past 150 years, the prevailing view of the local interstellar medium has been based on a peculiarity known as the Gould Belt1-4, an expanding ring of young stars, gas and dust, tilted about 20 degrees to the Galactic plane. However, the physical relationship between local gas clouds has remained unknown because the accuracy in distance measurements to such clouds is of the same order as, or larger than, their sizes5-7. With the advent of large photometric surveys8 and the astrometric survey9, this situation has changed10. Here we reveal the three-dimensional structure of all local cloud complexes. We find a narrow and coherent 2.7-kiloparsec arrangement of dense gas in the solar neighbourhood that contains many of the clouds thought to be associated with the Gould Belt. This finding is inconsistent with the notion that these clouds are part of a ring, bringing the Gould Belt model into question. The structure comprises the majority of nearby star-forming regions, has an aspect ratio of about 1:20 and contains about three million solar masses of gas. Remarkably, this structure appears to be undulating, and its three-dimensional shape is well described by a damped sinusoidal wave on the plane of the Milky Way with an average period of about 2 kiloparsecs and a maximum amplitude of about 160 parsecs.

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