YouTube comments on astrobiology topics: sentiment and emotion analysis dataset

English-language YouTube comments (n=152,501) from videos on five astrobiology topics (K2-18b, Venus phosphine, Tabby's Star, ʻOumuamua, 3I/ATLAS), collected via YouTube Data API v3 (September 15–19, 2025). Comments in the dataset were published between October 20, 2015 and September 18, 2025. Includes comment text, like count, reply count, publish date, sentiment labels (TextBlob, VADER, DistilBERT), and emotion classifications (GoEmotions). User identifiers are anonymized. Used in: "Sentiment and emotion are weak predictors of engagement: A multi-method analysis of astrobiology topics on YouTube" (PLOS Complex Systems, to appear).