Banexcentricitet

Banexcentricitet, in orbital mechanics often called orbital eccentricity, is a dimensionless parameter that describes the shape of an object’s orbit around a central body. It ranges from 0 for a perfect circle to values between 0 and 1 for an ellipse, equals 1 for a parabola, and exceeds 1 for a hyperbola. For bound orbits around a central mass, banexcentricitet lies in the interval 0 ≤ e < 1.

Mathematically, e can be related to the orbital energy and angular momentum. In a two-body system with gravitational parameter μ = GM, e = sqrt(1 + 2ε h^2 / μ^2), where ε is the specific orbital energy and h is the specific angular momentum. For an ellipse with semi-major axis a and semi-minor axis b, e = sqrt(1 − b^2/a^2). The closest and farthest distances in the orbit are q = a(1 − e) and Q = a(1 + e), respectively.

In practice, banexcentricitet is one of the canonical orbital elements used to describe an orbit, alongside the semi-major axis, inclination, and other parameters. It can be inferred from observations such as radial velocity measurements, astrometric data, or transit timing variations. Population differences appear in eccentricity distributions, with some systems exhibiting near-circular orbits due to tidal circularization, while others retain significant elongation from gravitational interactions or formation histories.

Significance wise, e influences the speed and distance variation along the orbit and the timing of orbital events. The orbital period in a purely Keplerian two-body problem depends primarily on the semi-major axis and is largely independent of eccentricity.