periapsis

Scientific  

/ pĕr′ē-ăp′sĭs /

PLURAL

periapsides

1. The point at which an orbiting object is closest to the center of mass of the body it is orbiting. This point is sometimes given a name that is specific to the body being orbited. For example, the periapsis of an object orbiting Earth is its perigee (from gaia, the Greek word for Earth), and the periapsis of an object orbiting the Sun is its perihelion (from hēlios, the Greek word for Sun). According to Kepler's laws of planetary motion, an object is at its greatest velocity at the periapsis.

2. Compare apoapsis

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Example Sentences

On each of a moon’s orbits, periapsis shifts a little farther around the planet until it eventually returns to where it was.

From Economist

The answer is that the Earth’s orbit is very close to circular, and so periapsis is only about 3% closer to the Sun than the furthest point in our great elliptical orbital loop.

From Scientific American

The point at which a moon and its planet come closest together, known as periapsis, is not constant.

From Economist

As a result, HD 80606b experiences a rise in its outer atmospheric temperature of over 700 degrees Celsius in the space of 6 hours as it rockets through its periapsis with the star.

From Scientific American

At first the planet has not yet passed through its periapsis, the blue color is light from the star reflected towards us.

From Scientific American