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
- 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
- DL - luminosity distance, ''obtaining an objects distance using only visual aspects''
Galaxy comparison
Galaxy type and spectral comparison:Luminosity comparison
Luminosity comparison:LS, - luminosity of the SunLuminosity of certain object:
- Lacc - accretion luminosity
- Lbol - bolometric luminosity
Mass comparison
Mass comparison:ME, M? - mass of EarthMass of certain object:
- M● - mass of black hole
- Macc - mass of accretion disc
Metallicity comparison
Metallicity comparison:- - 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.
- - 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 EarthSpectral comparison
Spectral comparison:- see Stellar classification
- m - Apparent magnitude
- M - Absolute magnitude, for galaxies and stars
- H - Absolute magnitude, ''for planets and nonstellar objects''