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 Δ - Distance from Earth ø - Geographical or astronomical 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, M🜨 - 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

See also List of astronomy acronyms Astronomical symbols Stellar classification Galaxy morphological classification List of astronomical catalogues Glossary of astronomy

References