Controlled Vocabularies and Thesauri in Astronomy: Tracing the Past, Present, and Future

Controlled vocabularies and thesauri, which traditionally relied on manual curation, are now transforming into AI-enhanced semantic frameworks. As a data-intensive field, astronomy has long practiced thesaurus construction and curation to enhance subject indexing, discovery, and semantic interoperability. Since the launch of PACS in 1975, successive milestones such as the IAU Thesaurus (1992), ADS's T-REX (1999), IVOA SKOS vocabularies (2007), and the Unified Astronomy Thesaurus (2012) have shaped the evolution of SciX, which integrates AI/ML/LLM technologies to aggregate literature, software, and data services within astronomical databases and repositories. AI-driven semantic curation brings both opportunities and challenges, serving as a testbed for automated knowledge organization. To systematically identify these challenges and emerging trends, a comprehensive analysis is required. This in-progress systematic literature review examines the shifts from human-curated thesauri to AI integration with controlled vocabularies in astronomy, analyzing key trends, advancements, and gaps by employing science mapping and topic modeling methods. Data are collected from Web of Science and SciX within the scope of astronomy and astrophysics domain. The findings is expected to guide libraries and data centers for AI deployment in astronomical knowledge systems.