List of common astronomy symbols

This is a compilation of symbols commonly used in astronomy, particularly professional astronomy.

Age (stellar)

 * τ - age

Astrometry parameters
Astrometry parameters
 * Rv - radial velocity
 * cz - apparent radial velocity
 * z - Redshift
 * μ - proper motion
 * π - parallax
 * J - epoch
 * α - Right Ascension
 * δ - Declination
 * λ - Ecliptic longitude
 * β - Ecliptic latitude
 * l - Galactic longitude
 * b - Galactic latitude

Cosmological parameters
Cosmological parameters
 * h - dimensionless Hubble parameter
 * H0 - Hubble constant
 * Λ - cosmological constant
 * Ω - density parameter
 * ρ - density
 * ρc - critical density
 * z - redshift

Distance description
Distance description for orbital and non-orbital parameters:
 * d - distance
 * d - in km = kilometer
 * d - in mi = mile
 * d - in AU = astronomical unit
 * d - in ly = light-year
 * d - in pc = parsec
 * d - in kpc = kiloparsec (1000 pc)
 * DL - luminosity distance, obtaining an objects distance using only visual aspects

Galaxy comparison
Galaxy type and spectral comparison:
 * see galaxy morphological classification

Luminosity comparison
Luminosity comparison:
 * LS, - luminosity of the Sun

Luminosity of certain object:
 * Lacc - accretion luminosity
 * Lbol - bolometric luminosity

Mass comparison
Mass comparison:
 * ME, - mass of Earth
 * , - mass of Jupiter
 * MS, - mass of the Sun

Mass of certain object:
 * M● - mass of black hole
 * Macc - mass of accretion disc

Metallicity comparison
Metallicity comparison:
 * [Fe/H] - Ratio of Iron to Hydrogen. This is not an exact ratio, but rather a logarithmic representation of the ratio of a star's iron abundance compared to that of the Sun.
 * for a given star (﹡) :, where the values represent the number densities of the given element.
 * [M/H] - Metallicity ratio.
 * Z - Metallicity
 * Z☉, ZS - Metallicity of the Sun

Orbital parameters
Orbital Parameters of a Cosmic Object:
 * α - RA, right ascension, if the Greek letter does not appear, á letter will appear.
 * δ - Dec, declination, if the Greek letter does not appear, ä letter will appear.
 * P or Porb or T - orbital period
 * a - semi-major axis
 * b - semi-minor axis
 * q - periapsis, the minimum distance
 * Q - apoapsis, the maximum distance
 * e - eccentricity
 * i - inclination
 * Ω - longitude of ascending node
 * ω - argument of periapsis
 * RL - Roche lobe
 * M - Mean anomaly
 * Mo - Mean anomaly at epoch

Radius comparison
Radius comparison:
 * RE, - Radius compared to Earth
 * , - Radius compared to Jupiter
 * RS, - Radius compared to The Sun

Spectral comparison
Spectral comparison:
 * see Stellar classification
 * m(object) - Apparent magnitude
 * M(object) - Absolute magnitude, for galaxies and stars
 * H(object) - Absolute magnitude, for planets and nonstellar objects

Temperature description
Temperature description:
 * Teff - Temperature Effect, usually associated with luminous object
 * Tmax - Temperature Maximum, usually associated with non-luminous object
 * Tavg - Temperature Average, usually associated with non-luminous object
 * Tmin - Temperature Minimum, usually associated with non-luminous object
 * K - Kelvin