LBV 1806−20

[[Image:LBV_1806-20.jpg

LBV_1806-20]]

LBV 1806-20 is located 49,000 light years from our Sun, on the other side of the galaxy. It has a mass of 130 Solar masses and a variable luminosity of 5-40 million times that of the Sun, making it more than 6 times as luminous as Eta Carinae or the Pistol Star, the previous contenders for the brightest star (all of which are Luminous Blue Variables).

Despite its high luminosity, it is virtually invisible from our Solar system, because nearly 90% of its light (visible and infrared) is absorbed by intervening interstellar gas and dust, giving it an apparent magnitude of 35 magnitudes at optical wavelengths, or 8 magnitudes at a wavelength of 2 microns.

Formation theory

Current star formation theories tell us that a star can be at most about 120 Solar masses, but this star has been measured to be at least 130 solar masses source.
Some even give the star 150 to 200 solar masses, but these are just unproved estimates. There has been some dispute as to whether LBV 1806-20 is a single star, or a cluster. Its luminosity has been estimated through very high-resolution speckle imaging, the results of which indicate that LBV 1806-20 is a single star. However, more recent high-resolution spectroscopy reveals that there is likely a companion and that the masses of each star in the system are each considerably less than 130 solar masses.

Location

LBV 1806-20 lies at the core of radio nebula G10.0-0.3 and is a component of cluster 1806-20, itself a component of W31, one of the largest H II regions in the Milky Way. Cluster 1806-20 is made up of some highly unusual stars, including at least two carbon-rich, Wolf-Rayet stars (WC9d and WCL), two blue hypergiants, and a magnetar (SGR 1806-20).

External links

http://arxiv.org/abs/astro-ph/0406316 http://arxiv.org/abs/astro-ph/0501560