luminous blue variable
(LBV, S Doradus variable)
(type of extremely bright variable stars)
A luminous blue variable (LBV or S Doradus variable after
an example in Large Magellanic Cloud) is a classification
of variable star that is extremely bright and rare,
consisting of the most luminous stars known,
hundreds of thousands times that of the Sun.
They are also among the most massive stars, up to 100 solar masses.
In addition to those in the Milky Way, they have been identified
in other galaxies such as the Magellanic clouds,
Andromeda, and Triangulum Galaxy and have been used to estimate distances
to the latter two galaxies.
Explanation of their structure and evolution continues
to be fodder for research.