Chemistry Around Newborn Star Investigated

Exploring the Chemistry Around a Newborn Star The James Webb Space Telescope (JWST), through an analysis by RIKEN researchers presenting early results demonstrating the instrument's ability to detect complex organic molecules in gas and ice clouds surrounding a newborn star, is poised to transform astronomers' understanding of the chemistry in newly forming stars. A protostar is a newly formed star that continues to feed from a envelope of material that has collapsed to form it. These envelopes contain chemical reactions that transform simple chemical building blocks into more complex organic molecules, which could be precursors to molecules required for the emergence of life. Researchers suspect that these complex organic molecules form in chemical reactions occurring on the surfaces of ice particles. As the star heats molecules, they leave the ice and mix into the surrounding gas. Yao-Lun Yang from RIKEN's Star and Planet Formation Laboratory said, "We want to obtain definitive evidence of exactly how these formation pathways occur," and added, "And JWST provides the best opportunity to do this." Beginning service in December 2021, JWST is located approximately 1.5 million kilometers from Earth. Yang, working with colleagues Yuki Okoda and Nami Sakai at RIKEN and members of the CORINOS team, used data from the telescope's Mid-Infrared Instrument (MIRI) to examine a very young protostar. When molecules absorb specific frequencies of infrared light, they bend and stretch in different ways depending on their structure. Since each type of molecule absorbs infrared light at a characteristic set of frequencies, the infrared spectrum detected by MIRI can determine which molecules are present around the protostar. Previous research on the protostar had identified complex organic molecules in the gas phase; because MIRI is able to detect organic molecules thought to form in ice, it presents a much more detailed picture. The results confirm the presence of water ice, carbon dioxide and silicates found in dust, as well as molecules such as ammonia, methane, methanol, formaldehyde and formic acid, with hints of ethanol and acetaldehyde. Protostars typically produce outflows and jets, and this protostar is no exception. MIRI produced images revealing the structure of one of the star's outflows, showing at least four envelope-like structures. The flow contains a range of elements including hydrogen, iron, nickel, neon, argon and sulfur. Some of it is concentrated in a relatively hot jet moving at approximately 200 kilometers per second. These jets are observed when the star is only 170 years old, a blink of an eye in the lifetime of a star. All of these results bode well for the future. Yang said, "We will begin to understand how organic chemistry emerges. Furthermore, we will also uncover its lasting effects on planetary systems similar to our solar system." Source: The work is published in The Astrophysical Journal Letters. More information: Yao-Lun Yang et al, CORINOS. I. JWST/MIRI Spectroscopy and Imaging of a Class 0 Protostar IRAS 15398–3359, The Astrophysical Journal Letters (2022). DOI: 10.3847/2041-8213/aca289 Journal information: Astrophysical Journal Letters / https://phys.org/news/2023-03-jwst-probes-chemistry-newborn-star.html