thumb|300px|right|Debris disks detected in HST archival images of young stars, HD 141943 and HD 191089, using improved imaging processes (24 April 2014). thumb|486958 Arrokoth, the first pristine planetesimal visited by a spacecraft.
A planetesimal is a small, rocky object in space that forms in the early stages of planetary development, combining together to eventually create planets. They matter because studying them—like the pristine planetesimal 486958 Arrokoth visited by spacecraft—helps scientists understand how planets form and what the early solar system was like.
AI-generated from the Wikipedia summary — may contain errors.
thumb|300px|right|Debris disks detected in HST archival images of young stars, HD 141943 and HD 191089, using improved imaging processes (24 April 2014). thumb|486958 Arrokoth, the first pristine planetesimal visited by a spacecraft.
Planetesimals () are solid objects thought to exist in protoplanetary disks and debris disks. Believed to have formed in the Solar System about 4.6 billion years ago, they aid study of its formation.
Discovered by embedding cosine similarity (sentence-transformers MiniLM, 384-dim).