The Orion A molecular cloud in the visible and infrared range.
Photo Credit:NASA, ESA, M.Robberto and the Hubble Space Telescope Orion Treasury Project Team
Scientific Frontline: Extended "At a Glance" Summary: Mapping Interstellar Ices in Protostellar Shells
The Core Concept: The detailed mapping of the spatial distribution and chemical composition of interstellar ices within the dense gas and dust shells of early-stage forming stars (Class 0 protostars) in the Orion A molecular cloud.
Key Distinction/Mechanism: By combining highly sensitive James Webb Space Telescope data with laboratory space ice analogues, researchers generated the first pixel-by-pixel absorption maps of key molecular components, transitioning from disparate data points to detailed structural maps of inner protostellar shells.
Origin/History: A collaborative study published in The Astrophysical Journal by researchers from Ural Federal University, Moscow, and Urumqi, targeting six Class 0 protostars (such as HOPS-56 and HOPS-108) within the Orion A molecular cloud.
Major Frameworks/Components:
- High-resolution and high-sensitivity spectral analysis utilizing the James Webb Space Telescope.
- Comparative baseline analysis using space ice analogues generated at the UrFU ISEAge laboratory facility.
- Pixel-by-pixel absorption mapping of critical molecular components, including water, carbon dioxide, carbon monoxide, cyanate ion, ammonium ion, and formaldehyde.
- Thermal evolution tracking, demonstrated by the sublimation of carbon monoxide from heated dust particles near the central stellar source.
Branch of Science: Astrochemistry, Astrophysics, and Astronomy.
Future Application: Refining chemical evolution models to accurately predict the chemical composition and potential habitability of planets forming in young stellar systems.
Why It Matters: This research demonstrates that interstellar ice forms primarily at the prestellar stage and evolves alongside the protostar, acting as the foundational reservoir for the complex molecules and chemical "building blocks" necessary for planetary formation and the potential origin of life.
Data from the Shells of Young Objects in the Orion A Molecular Cloud Will Help Us Understand the Processes of Star Formation and Composition
For the first time, a group of scientists from Ural Federal University (UrFU) and colleagues from Moscow and Urumqi, China, have created detailed maps of interstellar ices in the shells of forming stars. To do this, the researchers studied the youngest and most active objects in the Orion A molecular cloud. The obtained data show how the composition of stars evolves and will help predict the chemical composition of planets forming in such systems.
"We used data from the James Webb Space Telescope, which has a sensitivity more than 100 times greater than that of previous telescopes and an angular resolution about 10 times better," says Igor Petrashkevich, a researcher at the UrFU Laboratory of Astrochemistry.
The spectra from the telescope were compared with laboratory spectra of space ice analogs obtained at the UrFU ISEAge facility. The comparison helped identify the chemical composition of the ice with high accuracy, even in extremely difficult cases.
"This allowed us to see for the first time the spatial distribution of ices around young stars and to build pixel-by-pixel absorption maps for key components of space ice, including water, carbon dioxide, carbon monoxide, cyanate ion, ammonium ion, and formaldehyde. As a result, the spatial resolution of the maps made it possible to discern the structure of the inner protostellar shells. For us, it's like moving from disparate points on a map to a detailed terrain plan," Petrashkevich adds.
A protostar is a star at an early stage of formation, created when a cloud of gas and dust is compressed by gravity. Although thermonuclear reactions are not yet taking place within it, the protostar releases energy due to gravitational compression. Its shell—a cloud of gas and dust consisting of matter from an interstellar cloud—surrounds the forming protostar and increases its mass through accretion.
The scientists studied six Class 0 protostars (HOPS-56, HOPS-60, HOPS-73, HOPS-91, HOPS-96, and HOPS-108) in the Orion A molecular cloud. These are the youngest and most active star-forming objects, surrounded by dense dust shells. Analysis of the maps showed that ice forms mainly during the prestellar stage and evolves alongside the protostar, forming the foundation for the chemical composition of planetary systems. The analysis also revealed that the composition of the ice is heterogeneous.
The scientists compared the concentrations of various molecules in the shells and found that the protostars could be divided into two groups based on the relative abundance of ice. This may indicate differences in the evolutionary ages of the protostars or the conditions within their shells, such as temperature and density.
"We didn't just make maps—we traced the chemical changes taking place during the evolution of the protostar. For example, a decrease in carbon monoxide content near a central source indicates that the ice is heating up and the molecules are escaping from the dust particles. This is a key mechanism that enriches the gas in an emerging planetary system with complex molecules potentially important for the origin of life. Our work is an important step toward understanding how the 'building blocks' of planets are distributed in space. In the future, our results will help refine models of chemical evolution and predict what chemical composition planets forming in such systems may have," explains Anton Vasyunin, head of the UrFU Laboratory of Astrochemistry.
Funding: The work was supported by the Russian Ministry of Science and Higher Education (state assignment FEUZ-2025-0003).
Published in journal: The Astrophysical Journal
Authors: Igor Petrashkevich, Yaroslav Pavlyuchenkov, Anna Punanova, Maksim Ozhiganov, Ruslan Nakibov, Varvara Karteyeva, Svetlana Salii, Andrej Sobolev, Mikhail Medvedev, and Anton Vasyunin
Source/Credit: Ural Federal University | Delfina Zakharova
Edited by: Scientific Frontline
Reference Number: asph091026_01
