luminosity class
(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 factor in its luminosity.
A star's spectral type is often cited with its luminosity
class as a suffix. A general class is indicated by a Roman numeral:
As an example, the Sun's spectral type (G2) is commonly given
with a "V" suffix indicating it is in the main sequence, as "G2 V"
or "G2V" .
Additional more-specific classes:
- 0 (zero) (or Ia+ or IA-0) - extreme luminous supergiant, aka, hypergiant.
- Ia - luminous supergiant.
- Ib - supergiant less luminous than Ia.
- Iab - intermediate between Ia and Ib.
- D (or VII) - white dwarf.
Sometimes a, b, or ab are used for other class numbers besides I.
An analogous classification (luminosity class) for galaxies is the
van den Bergh galaxy classification.
(stars,classification,luminosity)
Further reading:
https://en.wikipedia.org/wiki/Stellar_classification
http://astronomy.swin.edu.au/cosmos/M/Morgan-Keenan+Luminosity+Class
https://www.oxfordreference.com/display/10.1093/oi/authority.20110803100118657
http://spiff.rit.edu/classes/phys440/lectures/lumclass/lumclass.html
Referenced by pages:
astronomical quantities
David Dunlap Observatory Catalog (DDO)
galaxy classification
M-type star (M)
main sequence star (MS)
spectral type
stellar astronomy
subdwarf (sd)
subgiant
Index