This article is about the brightness of stars. For the science fiction magazine, see Absolute Magnitude (magazine).
In astronomy, absolute magnitude (M) is a measure of the luminosity of a celestial object on an inverse logarithmic astronomical magnitude scale. An object's absolute magnitude is defined to be equal to the apparent magnitude that the object would have if it were viewed from a distance of exactly 10 parsecs (32.6 light-years), without extinction (or dimming) of its light due to absorption by interstellar matter and cosmic dust. By hypothetically placing all objects at a standard reference distance from the observer, their luminosities can be directly compared among each other on a magnitude scale. For Solar System bodies that shine in reflected light, a different definition of absolute magnitude (H) is used, based on a standard reference distance of one astronomical unit.
Absolute magnitudes of stars generally range from approximately −10 to +20. The absolute magnitudes of galaxies can be much lower (brighter).
The more luminous an object, the smaller the numerical value of its absolute magnitude. A difference of 5 magnitudes between the absolute magnitudes of two objects corresponds to a ratio of 100 in their luminosities, and a difference of n magnitudes in absolute magnitude corresponds to a luminosity ratio of 100n/5. For example, a star of absolute magnitude MV = 3.0 would be 100 times as luminous as a star of absolute magnitude MV = 8.0 as measured in the V filter band. The Sun has absolute magnitude MV = +4.83.[1] Highly luminous objects can have negative absolute magnitudes: for example, the Milky Way galaxy has an absolute B magnitude of about −20.8.[2]
As with all astronomical magnitudes, the absolute magnitude can be specified for different wavelength ranges corresponding to specified filter bands or passbands; for stars a commonly quoted absolute magnitude is the absolute visual magnitude, which uses the visual (V) band of the spectrum (in the UBV photometric system). Absolute magnitudes are denoted by a capital M, with a subscript representing the filter band used for measurement, such as MV for absolute magnitude in the V band.
An object's absolute bolometric magnitude (Mbol) represents its total luminosity over all wavelengths, rather than in a single filter band, as expressed on a logarithmic magnitude scale. To convert from an absolute magnitude in a specific filter band to absolute bolometric magnitude, a bolometric correction (BC) is applied.[3]
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and 22 Related for: Absolute magnitude information
In astronomy, absolutemagnitude (M) is a measure of the luminosity of a celestial object on an inverse logarithmic astronomical magnitude scale. An object's...
Measurement in the V-band may be referred to as the apparent visual magnitude. Absolutemagnitude is a measure of the intrinsic luminosity of a celestial object...
astronomical magnitude system: the absolute bolometric magnitude (Mbol) of an object is a logarithmic measure of its total energy emission rate, while absolute magnitude...
ordered rings, fields and vector spaces. The absolute value is closely related to the notions of magnitude, distance, and norm in various mathematical...
which compensates for the distances, converting the apparent magnitude to the absolutemagnitude, see the list of most luminous stars. The Sun is the brightest...
about magnitude +6. On both apparent and absolutemagnitude scales, the smaller the magnitude number, the brighter the star; the larger the magnitude number...
only by its magnitudeAbsolutemagnitude, the brightness of a celestial object corrected to a standard luminosity distance Apparent magnitude, the calibrated...
measurements that are calibrated in absolute units, namely spectral flux densities. The monochromatic AB magnitude is defined as the logarithm of a spectral...
d=10^{(m-M+5)/5}} where m is the apparent magnitude, and M the absolutemagnitude. For this to be accurate, both magnitudes must be in the same frequency band...
et al. give a blue absolutemagnitude of −20.8. Combined with a color index of 0.55 estimated here, an absolute visual magnitude of −21.35 (−20.8 − 0...
is called the apparent magnitude. The apparent magnitude depends on the intrinsic brightness (also called absolutemagnitude) of the object and its distance...
apparent magnitude of +8.0, making it easily visible with amateur telescopes, and is considered by some authors to be the galaxy with the highest absolute magnitude...
252)0.5 / 2 = 778 ± 33. Blue absolutemagnitude of −21.58 (see reference) – Color index of 0.63 = absolute visual magnitude of −22.21 "Results for Messier...
apparent magnitude of 5.05, making it visible to the naked eye only from locations with dark skies, far from light pollution. The absolutemagnitude, i.e...
correction made to the absolutemagnitude of an object in order to convert its visible magnitude to its bolometric magnitude. It is large for stars which...
of less than 0.05 astronomical units (19.5 lunar distances) and an absolutemagnitude of 22 or brighter, the latter of which roughly corresponds to a size...
ratio for the Milky Way is 63.8 assuming a solar absolutemagnitude of 4.83, a Milky Way absolutemagnitude of −20.9, and a Milky Way mass of 1.25×1012 M☉...
absolutemagnitude assume the same distance, absolutemagnitude is in effect a measurement of an object's brightness. The lower an object's absolute magnitude...
light-years) to HD 63332. Considering the apparent magnitude and distance from Earth, the star's absolutemagnitude is 3.66. No debris disks or exoplanets were...
absolutemagnitude of only +2.2, this makes it by far the Milky Way's dimmest satellite, and only about as bright as Altair. This absolutemagnitude corresponds...
an apparent magnitude of 5.52, placing it on the border between 5th- and 6th-magnitude stars. ζ2 Reticuli is slightly brighter at magnitude 5.22. The two...
any other conceivable or inconceivable quantity Absolutemagnitude, the brightness of a star Absolute value, a notion in mathematics, commonly a number's...
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