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List of common astronomy symbols

This is a compilation of symbols commonly used in astronomy, particularly professional astronomy.

Age (stellar)

ÃÂ - age

Astrometry parameters

Astrometry parameters

R<sub>v</sub> - radial velocity
cz - apparent radial velocity
z - Redshift
ÃÂ¼ - proper motion
ÃÂ - parallax
J - epoch
ÃÂ± - Right Ascension
ÃÂ´ - Declination
ÃÂ» - Ecliptic longitude
ÃÂ² - Ecliptic latitude
l - Galactic longitude
b - Galactic latitude
ÃÂ - Distance from Earth
ÃÂ¸ - Geographical or astronomical latitude

Cosmological parameters

Cosmological parameters

h - dimensionless Hubble parameter
H<sub>0</sub> - Hubble constant
ÃÂ - cosmological constant
ÃÂ© - density parameter
ÃÂ - density
ÃÂ<sub>c</sub> - 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)
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>, - luminosity of the Sun

Luminosity of certain object:

L<sub>acc</sub> - accretion luminosity
L<sub>bol</sub> - bolometric luminosity

Mass comparison

Mass comparison:

M<sub>E</sub>, M<sub>Ã°ÂÂÂ¨</sub> - mass of Earth
, - mass of Jupiter
M<sub>S</sub>, - mass of the Sun

Mass of certain object:

M<sub>Ã¢ÂÂ</sub> - 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 (Ã¯Â¹Â¡) : , where the values represent the number densities of the given element.
[M/H] - Metallicity ratio.
Z - Metallicity
Z<sub>Ã¢ÂÂ</sub>, Z<sub>S</sub> - Metallicity of the Sun

Orbital parameters

Orbital Parameters of a Cosmic Object:

ÃÂ± - RA, right ascension, if the Greek letter does not appear, ÃÂ¡ letter will appear.
ÃÂ´ - Dec, declination, if the Greek letter does not appear, ÃÂ¤ letter will appear.
P or P<sub>orb</sub> 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
ÃÂ© - longitude of ascending node
ÃÂ - 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>, - Radius compared to Earth
, - Radius compared to Jupiter
R<sub>S</sub>, - Radius compared to The Sun

Spectral comparison

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:

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
K - Kelvin

See also

References