absolute magnitude بُرز ِ ا َوَست borz-e avast Fr.: magnitude absolue The → magnitude a star would have if it were at a
distance of 10 → parsecs in a void space, without
→ interstellar absorption.
The absolute magnitude is usually deduced from the
→ visual magnitude, measured through a V filter
(→ UBV system), when it is written as MV. If
it is defined for another wavelength, it gets another index (U, B, etc).
If the radiation on all wavelengths is included, it becomes absolute
→ bolometric magnitude, Mbol.
The Sun has the absolute magnitude + 4.8. Most of the stars have absolute magnitudes ranging
between -9 (→ supergiants) and + 19
(→ red dwarfs)
(M.S.: SDE).
The brightness a → comet or → asteroid
would have if it were at a distance of 1 → astronomical unit
both from the Sun and the Earth and were completely illuminated by the Sun
(M.S.: SDE).
See also: → absolute; → magnitude. |
