List of common astronomy symbols

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

Age (stellar)

τ - age

Astrometry parameters

Cosmological parameters

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_L - 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_S - luminosity of the Sun (Sol)
L_☉ - luminosity of the Sun (Sol)

Luminosity of certain object:

L_acc - accretion luminosity
L_bol - bolometric luminosity

Mass comparison

Mass comparison:

M_E - mass of Earth
M_⊕ - mass of Earth
M_J - mass of Jupiter
M_♃- mass of Jupiter
M_S - mass of the Sun (Sol)
M_☉ - mass of the Sun (Sol)

Mass of certain object:

M_●^[1] - mass of black hole
M_acc - mass of accretion disc

Metallicity comparison

Metallicity comparison:

[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 of the Sun (Sol)
Z_☉ - Metallicity of 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 comparison

Radius comparison:

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)

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:

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

↑ 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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[1] 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