orbital element

In astronomy, an orbit is the path a celestial body takes around another body due to gravity, such as a planet around a star or a moon around a planet. The shape of an orbit is typically an ellipse, though some can be nearly circular, parabolic, or hyperbolic.1

An orbit is precisely defined by six orbital elements. These elements describe the orbit's size, shape, and orientation in space, allowing astronomers to calculate the future positions of the orbiting body. Key elements include the inclination of the orbit plane, the longitude of the ascending node, the semimajor axis, the eccentricity (which measures how much the orbit deviates from a circle), and the longitude of periapsis (the point of closest approach to the central body). The true anomaly, mean anomaly, and eccentric anomaly are used to describe a body's specific position along its orbital path at any given time.123