Newly developed map reveals mysterious molecules that affect starlight in Earth's galaxy

Astronomers have recently developed a new map of mysterious molecules in Earth's galaxy that has provided a deeper insight into a century-old puzzle.

By analyzing the light of hundreds of thousands of celestial objects, Johns Hopkins astronomers from the Sloan Digital Sky Survey (SDSS) have created a unique map of enigmatic molecules in our galaxy that are responsible for puzzling features in the light from stars.

These puzzling features in the light from stars, which astronomers call "Diffuse Interstellar Bands" (DIBs), have been a mystery ever since they were discovered by astronomer Mary Lea Heger of Lick Observatory in 1922. While analyzing the light from stars, she found unexpected lines that were created by something existing in the interstellar space between the stars and the Earth.

Further research showed that these mysterious lines were due to a variety of molecules. But exactly which of many thousands of possible molecules are responsible for these features has remained a mystery for almost a century.

This new map, based on SDSS data that reveals the location of these enigmatic molecules, was compiled from two parallel studies.

Ting-Wen Lan's team analyzed the light from more than half a million stars, galaxies, and quasars to detect the molecules' features in the regions well above and beyond the Milky Way's disk. In addition, the team was able to see the types of environments in which these molecules are more likely to be found. Some molecules like dense regions of gas and dust, and others prefer the lonelier spots far away from stars.

To look toward the galactic plane, hidden behind thick clouds of cosmic dust, Zasowski's team used data from the SDSS's APOGEE survey. APOGEE observations, which make use of infrared light, can easily see through interstellar dust and measure the properties of stars all over the galaxy.

The team members detected some of the mysterious features in front of about 60,000 stars in a wide range of environments and were even able to measure the motion of these molecules.

All the recent findings concerning these mysterious features paint a picture of tough little molecules that can exist in a variety of environments, all over the galaxy.