The darkest view ever achieved of interstellar ice

23 Jan. () –

Observations by the James Webb Space Telescope (JWST) to obtain the darkest image ever seen of a dense interstellar cloud.

These observations have revealed the composition of a virtual ‘treasure chest’ of ice from the early universe, providing new insights into the chemical processes of one of the coldest and darkest places in the universe, as well as on the origins of the molecules that make up planetary atmospheres.

“The JWST has allowed us to study the ices that exist in the dust grains of the darkest regions of interstellar molecular clouds,” he explains. it’s a statement Dr. Danna Qasim, a researcher at SwRI (Southwest Research Institute) and co-author of the study published in Nature Astronomy.

“The clouds are so dense that these ices have been mostly shielded from the harsh radiation of nearby stars, so they are quite pristine. These are the first ices to form, and they also contain biogenic elements, which are important for life,” he adds.

Webb has a 6.5 meter wide mirror that provides remarkable spatial resolution and sensitivity, optimized for infrared light. As a result, the telescope has been able to obtain images of the densest and darkest clouds in the universe for the first time.

“These observations provide new insights into chemical processes in one of the coldest and darkest places in the universe to better understand the molecular origins of protoplanetary disks, planetary atmospheres, and other Solar System objectsQassim said.

Most interstellar ice contains very small amounts of elements such as oxygen and sulfur. Qasim and his co-authors are trying to understand the lack of sulfur in interstellar ice.

“The ice sheets we observe only contain 1% of the sulfur we expect. 99% of that sulfur is locked up elsewhere, and we need to figure out where to understand how sulfur will eventually be incorporated into planets that can support life,” he explained. Qasim.

In the study, Qasim and his colleagues propose that sulfur may be locked up in reactive minerals such as iron sulfide, which can react with ice to form the sulfur-containing ice observed.

“Iron sulfide is a highly reactive mineral that has been detected in the accretion disks of young stars and in comet samples. It is also the most common sulfide mineral in lunar rocks,” explains Qasim. “If sulfur is locked up in these minerals, that could explain the low amount of sulfur in interstellar ices, which has implications for where sulfur is stored in our Solar System. For example, the atmosphere of Venus has sulfur-containing molecules, where the sulfur could come in part from interstellar minerals.“.