Interstellar Mapping Tackles a Dark Mystery

A series of pseudo-3D maps may help astronomers better understand the world outside our solar system, otherwise known as interstellar space. The maps pinpoint materials between stars in the Milky Way galaxy, and could help reveal the composition of these interstellar mediums.

"There's an old saying that 'We are all stardust,' since all chemical elements heavier than helium are produced in stars," Rosemary Wyse, a researcher at Johns Hopkins University, said in a recent release. "But we still don't know why stars form where they do. This study is giving us new clues about the interstellar medium out of which the stars form."

Wyse helped author a study recently published in the journal Science which details how pseudo-3D maps of interstellar space can help reveal what some light-absorbent material in an interstellar medium could be.

According to Wyse, this material was first noticed in 1922 when a series of photographs revealed lines of darkness through space - a darkness that should have been filled with starlight that appeared to be "missing."

Since then, astronomers have identified more than 400 of these darker portions of space, called diffuse interstellar bands (DIBs), but exactly what is absorbing the light and even where it is in each medium still remains a mystery.

"To figure out what something is, you first have to figure out where it is, and that's what this paper does," Wyse explained.

To help solve this, Wyse and 22 other experts collected spectroscopic data between 2003 and 2013 during the Radial Velocity Experiment (RAVE). They collected data on nearly 500,000 stars, helping the team of mapmakers precisely position each DIB's dusky and mysterious material. Interestingly, the maps show that the material does not follow the distribution of other interstellar material like dust.

According to the authors of the study, this is just a first clue, and now that researchers know where the DIBs are, the real work can begin.

"Larger surveys will provide more details in the future," said Wyse. "This paper has demonstrated how to do that."