View source for List of common astronomy symbols

{{Short description|none}}
This is a compilation of symbols commonly used in astronomy, particularly professional [[astronomy]].

==Age (stellar)==
* τ - age

==Astrometry parameters==
[[Astrometry]] parameters
* R<sub>v</sub> - [[radial velocity]]
* cz - apparent [[radial velocity]]
* z - [[Redshift]]
* μ - [[proper motion]]
* π - [[parallax]]
* J - [[Epoch (astronomy)|epoch]]
* α - [[Right Ascension]]
* δ - [[Declination]]
* λ - [[Ecliptic longitude]]
* β - [[Ecliptic latitude]]
* l - [[Galactic longitude]]
* b - [[Galactic latitude]]

==Cosmological parameters==
[[Cosmology|Cosmological]] parameters
* h - [[dimensionless Hubble parameter]]
* H<sub>0</sub> - [[Hubble constant]]
* Λ - [[cosmological constant]]
* Ω - [[Friedmann equations|density parameter]]
* ρ - [[Friedmann equations|density]]
* ρ<sub>c</sub> - [[Friedmann equations|critical density]]
* z - [[redshift]]

==Distance description==
Distance description for orbital and non-orbital parameters:
* d - distance
** d - in km = [[Kilometre|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)
* D<sub>L</sub> - [[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:
* ''L''<sub>S</sub>, {{Solar luminosity}} - luminosity of the [[Sun]]

Luminosity of certain object:
* L<sub>acc</sub> - accretion luminosity
* L<sub>bol</sub> - [[Luminosity#In astronomy|bolometric luminosity]]

==Mass comparison==
[[Mass]] comparison:
* ''M''<sub>E</sub>, {{Earth mass}} - mass of [[Earth]]
* {{Jupiter mass}}, {{Jupiter mass|greek=y}} - mass of [[Jupiter]]
* ''M''<sub>S</sub>, {{Solar mass}} - mass of the [[Sun]] 

Mass of certain object:
* M<sub>●</sub><ref>{{Cite journal |last1=Kuncic |first1=Z. |last2=Soria |first2=R. |last3=Hung |first3=C. K. |last4=Freeland |first4=M. C. |last5=Bicknell |first5=G. V. |date=August 2006 |title=Ultra-luminous X-ray sources: X-ray binaries in a high/hard state? |journal=Proceedings of the International Astronomical Union |volume=2 |issue=S238 |pages=247–250 |doi=10.1017/S1743921307005066 |arxiv=astro-ph/0611040 |issn=1743-9213}}</ref> - mass of [[black hole]]
* M<sub>acc</sub> - 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 chem>[\ce{Fe/H}] = \log[\ce{Fe/H}]_* - \log[\ce{Fe/H}]_\odot</math>, where the values represent the number densities of the given element. 
* [M/H] - Metallicity ratio.
* Z - Metallicity
* Z<sub>☉</sub>, Z<sub>S</sub> - Metallicity of the [[Sun]]

==Orbital parameters==
[[Orbital elements|Orbital Parameters]] of a Cosmic Object:
* α - [[Right ascension|RA]], ''right ascension, if the Greek letter does not appear, '''á''' letter will appear.''
* δ - [[Declination|Dec]], ''declination, if the Greek letter does not appear, '''ä''' letter will appear.''
* P or P<sub>orb</sub> or T - [[orbital period]]
* a - [[semi-major axis]]
* b - [[semi-minor axis]]
* q - [[apsis|periapsis]], ''the minimum distance''
* Q - [[apsis|apoapsis]], ''the maximum distance''
* e - [[Orbital eccentricity|eccentricity]]
* i - [[inclination]]
* Ω - [[longitude of the ascending node|longitude of ascending node]]
* ω - [[argument of periapsis]]
* R<sub>L</sub> - [[Roche lobe]]
* M - [[Mean anomaly]]
* M<sub>o</sub> - Mean anomaly at epoch

==Radius comparison==
[[Radius]] comparison:
* ''R''<sub>E</sub>, {{Earth radius}} - Radius compared to [[Earth]]
* {{Jupiter radius}}, {{Jupiter radius|greek=y}} - Radius compared to [[Jupiter]]
* ''R''<sub>S</sub>, {{Solar radius}} - Radius compared to The [[Sun]]

==Spectral comparison==
[[Astronomical spectroscopy|Spectral]] comparison:
* see [[Stellar classification]]
* m<sub>(object)</sub> - [[Apparent magnitude]]
* M<sub>(object)</sub> - [[Absolute magnitude]], ''for galaxies and stars''
* H<sub>(object)</sub> - Absolute magnitude, ''for planets and nonstellar objects''

==Temperature description==
[[Temperature]] description:
* [[Effective temperature|T<sub>eff</sub>]] - Temperature Effect, ''usually associated with luminous object''
* T<sub>max</sub> - Temperature Maximum, ''usually associated with non-luminous object''
* T<sub>avg</sub> - Temperature Average, ''usually associated with non-luminous object''
* T<sub>min</sub> - Temperature Minimum, ''usually associated with non-luminous object''
* [[Kelvin|K]] - Kelvin

==See also==
* [[List of astronomy acronyms]]
* [[Astronomical symbols]]
* [[Stellar classification]]
* [[Galaxy morphological classification]]
* [[List of astronomical catalogues]]
* [[Glossary of astronomy]]

==References==
{{reflist}}

[[Category:Astronomy-related lists|Symbols]]
[[Category:Lists of symbols|Astronomy]]