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
* R_v - radial velocity
* μ - proper motion
* π - parallax
* J - Epoch

Cosmological parameters

Cosmological parameters
* h - Dimensionless Hubble parameter
* H₀ - Hubble constant
* Λ - Cosmological constant
* Ω - Density parameter
* ρ - Density
* ρ_c - Critical density
* z - Redshift

Distance description

Distance description for Orbital and non-Orbital Parameters:
* d - distance
** d - in km = kilometer
** d - in mi = mile, "note, not an SI unit"
** d - in AU = astronomical unit
** d - in ly = light-year
** d - in kly = kilolight-year (1000 x 1ly)
** d - in pc = parsec
** d - in kpc = kiloparsec (1000 x 1pc)
* D_L - Luminosity distance, "obtaining an objects distance using only visual aspects"

Galaxy comparism

Galaxy type and spectral comparism:
* see Galaxy morphological classification

Luminosity comparism

Luminosity comparism:
* L_S - Luminosity compared to the Sun (Sol)
* L_☉ - Luminosity compared to the Sun (Sol)

Luminosity of certain object:
* L_acc - Accretion luminosity
* L_bol - Bolometric luminosity

Mass comparism

Mass comparism:
* M_E - Mass compared to Earth
* M_⊕ - Mass compared to Earth
* M_J - Mass compared to Jupiter
* M_♃ - Mass compared to Jupiter
* M_S - Mass compared to the Sun (Sol)
* M_☉ - Mass compared to The Sun (Sol)

Mass of certain object:
* M_● [ [http://xxx.lanl.gov/abs/astro-ph/0611040 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] - Mass of black hole
* M_acc - Mass of accretion disc

Metallicity comparism

Metallicity comparism:
* Fe/H - Iron ratio to Hydrogen, "a logarithm representation of the ratio of a star's iron abundance compared to that of the Sun"
* M/H - Metallicity ratio.
* Z - Metallicity
* Z_S - Metallicity compared to the Sun (Sol)
* Z_☉ - Metallicity compared to the Sun (Sol)

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 P_orb - orbital period
* a - semi-major axis
* b - semi-minor axis
* q - periapsis, "the minimum distance"
* Q - apsis, "the maximum distance"
* e - eccentricity
* i - inclination
* Ω - longitude of ascending node
* ω - argument of periapsis

* R_L - Roche lobe
* M - Mean anomaly
* M_o - Mean anomaly at epoch

Radius comparism

Radius comparism:
* R_E - Radius compared to Earth
* R_⊕ - Radius compared to Earth
* R_J - Radius compared to Jupiter
* R_♃ - Radius compared to Jupiter
* R_S - Radius compared to The Sun (Sol)
* R_☉ - Radius compared to The Sun (Sol)

pectral comparism

Spectral comparism:
* 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:
* T_eff - Temperature Effect, "usually associated with luminous object"
* T_max - Temperature Maximum, "usually associated with non-luminous object"
* T_avg - Temperature Average, "usually associated with non-luminous object"
* T_min - Temperature Minimum, "usually associated with non-luminous object"
* K - Kelvin

References

ee also

* List of astronomy acronyms
* Astronomical symbols
* Stellar classification
* Galaxy morphological classification