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, L☉ - luminosity of the Sun Luminosity of certain object:
Lacc - accretion luminosity Lbol - bolometric luminosity
Mass comparison Mass comparison:
ME, M🜨 - mass of Earth MJ, M♃ - mass of Jupiter MS, M☉ - 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 (﹡) : [ Fe / H ] = log [ Fe / H ] ∗ − log [ Fe / H ] ⊙ {\displaystyle [{\ce {Fe/H}}]=\log[{\ce {Fe/H}}]_{*}-\log[{\ce {Fe/H}}]_{\odot }} , 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, R🜨 - Radius compared to Earth RJ, R♃ - Radius compared to Jupiter RS, R☉ - 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