Life-forming molecules around a baby star observed, thanks to JWST

Complex organic molecules (COMs), possibly precursors to life-forming prebiotic molecules, were earlier thought to be present in high-mass cores but, over the years, have also been observed in the gas phase in low-mass protostellar cores. This suggests that extensive chemical evolution occurs in the early stages of low-mass protostar formation.

Researchers observed that COMs are formed in chemical reactions that transform simple chemical building blocks into more complex organic molecules. This process occurs on the surfaces of ice grains, and when the star warms these molecules, they leave the ice and mingle with the gas around them.

“We want to obtain definitive proof of such formation pathways,” says Yao-Lun Yang of the RIKEN Star and Planet Formation Laboratory. “And JWST provides the best opportunity to do so.”

Yang’s team is not the first to study protostar IRAS 15398−3359 or observe COMs in its clouds. However, with the help of MIRI, a much more detailed picture has come to the fore. The scientists are able to confirm the presence of water ice, carbon dioxide and silicates, and molecules like ammonia, methane, methanol, formaldehyde, and formic acid. They also could detect hints of ethanol and acetaldehyde.

“We will begin to understand how organic chemistry emerges,” says Yang. “And we will also uncover the lasting impacts on planetary systems similar to our Solar System.”