Telltale twist points to the birth of a baby alien world
Scott Sutherland
mardi, 26 mai 2020 à 08:45 - Astronomers spotted signs of brand new exoplanet forming around another star.
Astronomers have made another stride forward in their quest to image the birth of a planet around another star directly.
For decades, scientists have been developing the basic ideas about how planets form around stars. First, a star forms from a collapsing cloud of gas and dust. The remaining material surrounding the star is spun into a disk by the star s rotation, and parts of that disk clump together due to gravity. As these clumps gather more material to them, first planetesimals form, then protoplanets, and finally planets.
14:00
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The building blocks of planets are the dust, gas, and ice in the protoplanetary disks orbiting young stars. Deep, high resolution images of protoplanetary disks by ALMA have revealed complex and varied ring and spiral structures in a number of systems. In the Disk Substructures at High Angular Resolution Project (DSHARP), we undertook the first high angular resolution disk survey at millimeter wavelengths. DSHARP found that gaps and rings indicative of planet-disk interactions were widespread, implying that giant planet formation proceeds rapidly even at tens of au from the star. On the other hand, the origins of “grand design” millimeter continuum spiral arms are more enigmatic, and may point either to disk instabilities or the formation of super-Jovian planets at surprisingly wide separations. Gaps and rings are also common in molecular emission, and appear primarily to result from vigorous chemical