You searched for: “periastron
1. The points in space and time in the orbits of two stars in a binary system when they are closest to each other.
2. That point, in the real or apparent orbit of one star revolving around another (double-star systems), when the former star is nearest to the other star.
This entry is located in the following units: astro-, astr- + (page 9) peri- (page 3) -tron, -tronic, -tronics + (page 14)