User:2003 LN6/sandbox/Eta Carinae variable
An Eta Carinae variable, or Eruptive Superluminous Blue Variable (esLBV), is a category of variable star. These stars are extremely massive, short-lived, and luminous. The prototype of these stars is Eta Carinae. Currently, only five of these stars have been found, and only one (Eta Carinae) in the Milky Way. These stars are similar to normal Luminous Blue Variables, however they can undergo great eruptions, and are the only stars currently known to be able to surpass the Eddington luminosity, though only for a short time.
The star stays relatively stable when erupting for ten to twenty years, and then fades back to its normal luminosity. The Great Eruption of Eta Carinae was one example of this type of eruption. In their quiescent phase, they are between 1,000,000 and 10,000,000L☉, while they can go as high as 500,000,000L☉ at greatest eruption. Little is known about these stars, as they are exceptionally rare. Strangely, stars with masses higher than 120M☉ generally do not become η Carinae variables. Thus, they only appear in an extremely specific mass range from approximately 60M☉ to 100M☉, however there have been reports of higher mass objects of similar activity. It is unknown how these objects form, as young and more massive Wolf-Rayet stars are more common than these objects. In addition, their eruption mechanism is unclear. However, a known fact is that these stars emit intense waves of stellar wind during eruptions, losing as much as 2M☉/year. However, some have theorized that either it is an internal mechanism, caused by the star itself, or external mechanism, caused by a companion star in a hypermassive binary. There is evidence for both, as all confirmed Eta Carinae variables that could be carefully observed have a companion star orbiting very closely, while Eta Carinae's companion during the Great Eruption showed no major signs of any change happening.