Equations of astronomy

scientific laws describing motion of planets around the Sun

observation in physical cosmology

astronomical concept

classical mechanics problem of three massive point particles interacting via Newtonian gravity; special case of the 𝑛‐body problem for 𝑛=3

angular measurement describing how large a sphere or circle appears from a given point of view

with regards to an astronomical body, the region in which it dominates the attraction of satellites

general equation that relates the time-averaged total kinetic energy of a stable system consisting of N particles, bound by potential forces, with that of the time-averaged total potential energy

angular parameter of Keplerian orbits

named after Félix Tisserand

return of a perturbed system into equilibrium

Simplification of the basic trigonometric functions

maximally symmetric Lorentzian manifold with positive cosmological constant

empirical function that describes the initial distribution of masses for a population of stars

branch of astrophysics that statistically models the collective movement of stars

astronomical measurand

theoretical temperatures

astronomical measure of the number of stars or galaxies per luminosity interval

of a galaxy

Surface brightness model in astronomy

physical law that describes the motion of objects in a Keplerian orbit around a body

in astronomy, the statistical dispersion of velocities about the mean velocity for a cluster of stars or galaxies

angular speed required for a body to complete one orbit, assuming constant speed in a circular orbit which completes in the same time as the variable speed, elliptical orbit of the actual body

empirical power-law relation between the luminosity and the central stellar velocity dispersion of elliptical galaxy

mathematical function

measure of the dependence of radiative flux density on frequency (astronomical term)

ecliptic longitude at which an orbiting body could actually be found if its inclination were zero

formula to determine satellite orbital period

accretion of matter within the interstellar medium

mathematical function that describes how the density of a spherical stellar system varies with distance

mathematical model in dynamical systems

Relationship between the stellar mass dispersion of a galaxy bulge and the mass of the supermassive black hole at its center

largest mass that an isothermal gas sphere embedded in a pressurized medium can have while still remaining in hydrostatic equilibrium

oblate ellipsoid under equilibrium

characteristic of accretion discs

astrophysical theory relating the radiative flux of a star to the local effective gravity

astronomical concept