List of common astronomy symbols

From Wikipedia, the free encyclopedia

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

Contents 1 Age (stellar) 2 Astrometry parameters 3 Cosmological parameters 4 Distance description 5 Galaxy comparism 6 Luminosity comparism 7 Mass comparism 8 Metallicity comparism 9 Orbital parameters 10 Radius comparism 11 Spectral comparism 12 Temperature description 13 References 14 See also

[edit] Age (stellar)

• τ - Age

[edit] Astrometry parameters

Astrometry Parameters

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

[edit] 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

[edit] 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

[edit] Galaxy comparism

Galaxy type and spectral comparism:

• see Galaxy morphological classification

[edit] 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

[edit] 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_●^[1] - Mass of black hole
• M_acc - Mass of accretion disc

[edit] 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)

[edit] 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

[edit] 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)

[edit] Spectral 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

[edit] 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

[edit] References

[edit] See also

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