List of common astronomy symbols
This is a compilation of symbols commonly used in astronomy, particularly professional astronomy.
Age (stellar)
[edit]- τ - age
Astrometry parameters
[edit]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
[edit]Cosmological parameters
- h - dimensionless Hubble parameter
- H0 - Hubble constant
- Λ - cosmological constant
- Ω - density parameter
- ρ - density
- ρc - critical density
- z - redshift
Distance description
[edit]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
[edit]Galaxy type and spectral comparison:
Luminosity comparison
[edit]Luminosity comparison:
- LS, L☉ - luminosity of the Sun
Luminosity of certain object:
- Lacc - accretion luminosity
- Lbol - bolometric luminosity
Mass comparison
[edit]Mass comparison:
Mass of certain object:
- M●[1] - mass of black hole
- Macc - mass of accretion disc
Metallicity comparison
[edit]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
![{\displaystyle [{\ce {Fe/H}}]=\log[{\ce {Fe/H}}]_{*}-\log[{\ce {Fe/H}}]_{\odot }}](https://wikimedia.org/api/rest_v1/media/math/render/svg/b980e18f7a4ed5e8faa5eda06c55ec4851ae1fd2)
Orbital parameters
[edit]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
[edit]Radius comparison:
- RE, R🜨 - Radius compared to Earth
- RJ, R♃ - Radius compared to Jupiter
- RS, R☉ - Radius compared to The Sun
Spectral comparison
[edit]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
[edit]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
[edit]- List of astronomy acronyms
- Astronomical symbols
- Stellar classification
- Galaxy morphological classification
- List of astronomical catalogues
- Glossary of astronomy
References
[edit]- ^ Kuncic, Z.; Soria, R.; Hung, C. K.; Freeland, M. C.; Bicknell, G. V. (August 2006). "Ultra-luminous X-ray sources: X-ray binaries in a high/hard state?". Proceedings of the International Astronomical Union. 2 (S238): 247–250. arXiv:astro-ph/0611040. doi:10.1017/S1743921307005066. ISSN 1743-9213.