Astronomy:List of common astronomy symbols
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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:
Luminosity comparison
Luminosity comparison:
- LS, L☉ - luminosity of the Sun
Luminosity of certain object:
- Lacc - accretion luminosity
- Lbol - bolometric luminosity
Mass comparison
Mass comparison:
Mass of certain object:
- M●[1] - 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 ([math]\displaystyle{ * }[/math]) : [math]\displaystyle{ [\text{Fe}/\text{H}] = log[\text{Fe}/\text{H}]_* - log[\text{Fe}/\text{H}]_\odot }[/math], 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
- ↑ Ultra-luminous X-ray sources: X-ray binaries in a high/hard state?, Z. Kuncic, R. Soria, C. K. Hung, M. C. Freeland, G. V. Bicknell, 2006
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