S Doradus is the brightest star

Star

A star is a massive, luminous sphere of plasma held together by gravity. At the end of its lifetime, a star can also contain a proportion of degenerate matter. The nearest star to Earth is the Sun, which is the source of most of the energy on Earth...

 in the Large Magellanic Cloud

Large Magellanic Cloud

The Large Magellanic Cloud is a nearby irregular galaxy, and is a satellite of the Milky Way. At a distance of slightly less than 50 kiloparsecs , the LMC is the third closest galaxy to the Milky Way, with the Sagittarius Dwarf Spheroidal and Canis Major Dwarf Galaxy lying closer to the center...

, a satellite

Satellite galaxy

A satellite galaxy orbits a larger galaxy due to gravitational attraction. Although a galaxy is made of a large number of objects which are not connected to each other, it has a center of mass, which represents a weighted average of the positions of each component object...

 of the Milky Way

Milky Way

The Milky Way is the galaxy that contains the Solar System. This name derives from its appearance as a dim un-resolved "milky" glowing band arching across the night sky...

. A hypergiant

Hypergiant

A hypergiant is a star with a tremendous mass and luminosity, showing signs of a very high rate of mass loss.-Characteristics:...

, it is one of the most luminous stars known (sometimes more luminous than −10 absolute magnitude

Absolute magnitude

Absolute magnitude is the measure of a celestial object's intrinsic brightness. it is also the apparent magnitude a star would have if it were 32.6 light years away from Earth...

), but so far away that it is invisible to the naked eye

Naked eye

The naked eye is a figure of speech referring to human visual perception unaided by a magnifying or light-collecting optical device, such as a telescope or microscope. Vision corrected to normal acuity using corrective lenses is considered "naked"...

.

This star belongs to its own eponymous S Doradus class of variable stars (these classes are usually named after their prototypes);
also designated as the class luminous blue variable

Luminous blue variable

Luminous blue variables, also known as S Doradus variables, are very bright, blue, hypergiant variable stars named after S Doradus, the brightest star of the Large Magellanic Cloud. They exhibit long, slow changes in brightness, punctuated by occasional outbursts in brightness during substantial...

or LBV.
S Doradus exhibits long, slow changes in brightness, punctuated by occasional outbursts.

External links

• http://seds.org/~spider/Spider/Misc/sDor.html
• http://www.daviddarling.info/encyclopedia/S/S_Doradus.html
• http://books.google.com.br/books?id=sIcdZ3VKdpEC&pg=PA151&lpg=PA151&dq=%22S+Doradus%22&source=web&ots=RTPYWXf5c5&sig=BmO4BwtwgJuwuvvU3DDJxeBfkG8&hl=pt-BR#PPA152,M1
• http://jumk.de/astronomie/big-stars/s-doradus.shtml