A song of ice and gas: the formation and evolution of complex organic molecules

Chen, Y. (2026)

Doctoral Thesis

Understanding how chemical complexity emerges during star formation requires connecting molecular material preserved in interstellar ices with that observed in the gas phase after protostellar heating begins. This thesis addresses this challenge by examining the chemistry of complex organic molecules (COMs) in both the gas and the solid phases in large samples of protostars with different masses and luminosities. The results suggest that much of the observed molecular complexity is already established prior to the protostellar phase, while gas-phase chemistry in later stages can also introduce source-dependent variations. Overall, this thesis advances a more connected view of interstellar chemistry, in which gas and ice are understood as complementary tracers of a shared chemical history in star-forming regions.

• Astrochemistry
• Interstellar medium
• Complex organic molecules
• Molecular abundances
• Star formation
• Protostars
• Spectroscopy
• Interferometry
• Infrared

• All authors: Chen, Y.
• Supervisor: Dishoeck, E.F. van
• Co-supervisor: Gelder, M.L. van
• Committee: Snellen, I.A.G.; Viti, S.; Jørgensen, J.K.; Sakai, N.; Lee, J.-E.
• Qualification: Doctor (dr.)
• Awarding Institution: Leiden Observatory, Faculty of Science, Leiden University
• Date: 2026-02-24
• ISBN (print): 9789465342061