Why sibling stars look alike: Early, fast mixing in star-birth clouds

In other runs of the simulation, Krumholz and Feng observed that even clouds that do not turn much of their gas into stars—as the Sun's parent cloud probably didn't—still produce stars with nearly-identical abundances. "We've provided the missing physical explanation of how and why chemical mixing works, and shown convincingly that the chemical mixing process is very general and rapid even in an environment which did not yield a star cluster, like the one where the Sun must have formed," said Krumholz.

The finding puts the idea of chemical tagging on much firmer footing. "This is good news for prospects for finding the Sun's long-lost siblings," Krumholz stated.

This 11-second movie shows a computational simulation of a collision of two converging streams of interstellar gas, leading to collapse and formation of a star cluster at the center. Face-on view shows the plane where the two gas streams meet. Numbers rapidly increasing at upper left shows the passage of time in millions of years. Left panel shows the density of interstellar gas (yellow and red are densest) and right panel shows red and blue "tracer dyes" added to watch how the gas mixes during the collapse. Circles outlined in black are stars; stars are shown as white in the left panel, and in the right panel their color reflects the amount of the two tracer dyes in each star. The simulation reveals that gas streams are thoroughly homogenized within a very short time of converging, well before stars begin forming.

(Photo Credit: Mark Krumholz/University of California, Santa Cruz)

This 11-second movie shows a computational simulation of a collision of two converging streams of interstellar gas, leading to collapse and formation of a star cluster at the center. Edge-on view shows a cross section through the two meeting streams of gas. Numbers rapidly increasing at upper left shows the passage of time in millions of years. Left panel shows the density of interstellar gas (yellow and red are densest) and right panel shows red and blue "tracer dyes" added to watch how the gas mixes during the collapse. Circles outlined in black are stars; stars are shown as white in the left panel, and in the right panel their color reflects the amount of the two tracer dyes in each star. The simulation reveals that gas streams are thoroughly homogenized within a very short time of converging, well before stars begin forming.

(Photo Credit: Mark Krumholz/University of California, Santa Cruz)

Two 11-second movies show a computational simulation of a collision of two converging streams of interstellar gas, leading to collapse and formation of a star cluster at the center. In both movies, the numbers rapidly increasing shows the passage of time in millions of years; left panel shows the density of interstellar gas (yellow and red are densest) and right panel shows red and blue "tracer dyes" added to watch how the gas mixes during the collapse. Face-on view (upper pair in the stills) shows the plane where the two gas streams meet while the edge-on view (lower pair in the stills) shows a cross section through the two streams. Circles outlined in black are stars; stars are shown as white in the left panel, and in the right panel their color reflects the amount of the two tracer dyes in each star. The simulation reveals that gas streams are thoroughly homogenized within a very short time of converging, well before stars begin forming.

(Photo Credit: Mark Krumholz/University of California, Santa Cruz)

Source: University of California High-Performance AstroComputing Center