Asteroid Occultations (Shape Modeling)

Canonical version: NewOpenAstro/Science/Projects/Stellar Occultations — Complete.md This note preserved. The merged version combines this with STELLAR OCCULTATIONS BY SMALL BODIES.md and adds technical tables.

Determining the precise 3D shape and size of an asteroid is difficult from a single point of light.

  • The Solution: When an asteroid passes in front of a distant star (an occultation), it casts a shadow on Earth. If a distributed array of telescopes forms a "picket fence" line across the shadow path, each telescope sees the star disappear for a different duration. Combining these chords reconstructs the asteroid's silhouette with kilometer-level precision.

  • Real-World Example: The Unistellar Network (eVscope users) successfully characterized the asteroid Eurybates (a target for NASA's Lucy mission) and helped track the James Webb Space Telescope during its deployment.4

  • Source: Citizen Science Astronomy with a Network of Small Telescopes: The Launch and Deployment of JWST (2022).5

  • Stellar Occultations: Geographic spread = multiple chords = 2D shape reconstruction. Equipment: 8" SCT + fast CMOS + GPS = $3K minimum. Failure modes: timing drift, wrong star, clouds.