Radcliffe wave


The Radcliffe wave is the nearest coherent gaseous structure in the Milky Way, dotted with a related high concentration of interconnected stellar nurseries. It stretches about 8,800 light years. It runs with the trajectory of the Milky Way arms, and lies at its closest at around 400 light-years and at its farthest about 5000 light-years from the Sun, always within the Local Arm itself, spanning about 40% of its length and on average 20% of its width. Its discovery was announced in January 2020 and its proximity surprised astronomers.

Formation

Scientists do not know how the undulation of dust and gas formed; it has been suggested that it could be a result of a much smaller galaxy colliding with the Milky Way, leaving behind "ripples", or could be related to dark matter. Inside the dense clouds, gas can be so compressed that new stars are born; it has been suggested that this may be where the Sun originated.
Many of the star-forming regions found in the Radcliffe wave were thought to be part of a similar-sized but somewhat helio-centric ring in which sat our solar system, "the Gould Belt". It it is now understood the nearest, discreet, relative concentration of sparse interstellar matter instead forms a massive wave.

Discovery

The wave was discovered by an international team of astronomers including Catherine Zucker and João Alves. It was announced by co-author Alyssa A. Goodman at the 235th meeting of the American Astronomical Society, held at Honolulu and published in the journal Nature on 7 January 2020. The discovery was made using data collected by the European Space Agency's Gaia space observatory. The wave was invisible in 2D, requiring new 3D techniques of mapping interstellar matter to reveal its pattern. The proximity of the wave surprised astronomers. It is named after the Radcliffe Institute for Advanced Study in Cambridge, Massachusetts, the place of study of the team.

Overview

The Radcliffe wave contains four of the five Gould Belt clouds, the:
The cloud not within its scope is the Rho Ophiuchi Cloud complex, part of a parallel, linear structure to the Radcliffe wave.
Other structures in the wave, further from the local star system are Canis Major OB1, the North America Nebula and Cygnus X.
The mass of this structure is on the scale of , it has a length of 8.8 kilolight-years and an amplitude of 520 light-years. The Radcliffe wave occupies about 20% of the width and 40% of the length of the local arm. The latter is more dispersed as to its interstellar medium than the wave and has further, large, star-forming regions such as Monoceros OB1, California Nebula, Cepheus Far, Rho Ophiuchi.