Izell

Izell was a blue giant star with an associated system located in Federation space within the Milky Way Galaxy. It had a diameter of approximately ten million kilometers, and was 51,500 times more powerful than Sol. It was a fifth magnitude star, and one of the brightest stars known to the Federation.

The system had eight planets, none of which were life-bearing or colonized.

History
At least until the 2260s, tourist agencies conducted sightseeing tours of Izell in shuttlecraft.

In the year 2268, during testing of a new deflector shield system linked to the warp drive, the USS Enterprise (NCC-1701) inadvertantly created an accretion disk that allowed a cosmic string to form and consume nearly a quarter of Izell's mass. 

Discrepancies
Izell is described as a blue giant in First Frontier (before it lost a quarter of its mass) but also larger than Rigel which is a supergiant star. The fact that it is a fifth magnitude star also creates uncertainty as to being one of the brightest known stars.