(Morgan-Keenan luminosity class, MK luminosity class, MK class, stellar luminosity class)
(classification of size/luminosity of stars)
A star's luminosity class (or Morgan-Keenan luminosity class
or MK luminosity class or MK class)
is a classification (star class) of the overall size of a star
(as are terms like giant star, supergiant, etc.)
which is a major contributor to its luminosity.
A description of a star might include its spectral type
and luminosity class. The general classifications are indicated
by Roman numerals:
- 0 (zero) (or Ia+ or IA-0) - extreme luminous supergiant, aka, hypergiant.
- Ia - luminous supergiant.
- Ib - less luminous supergiant.
- Iab - intermediate between Ia and Ib.
- D - white dwarf (or VII).
The system is termed the Morgan-Keenan classification system.
An analogous classification for galaxies is the
van den Bergh galaxy classification.
Referenced by pages:
David Dunlap Observatory Catalog (DDO)
main sequence star (MS)
M-type star (M)