1. of, relating to, or occurring at perihelion (the point in an orbit closest to the sun)
Usage: astronomy; technical

Examples

• The comet's perihelial distance is only 0.5 astronomical units from the sun.
• Perihelial velocity increases as the planet approaches its closest point to the sun.
• Astronomers measured the perihelial passage of the asteroid last month.
• The spacecraft's perihelial orbit brings it within 50 million kilometers of the sun.
• During perihelial approach, the comet becomes increasingly bright and visible from Earth.