VY Canis Majoris

VY Canis Majoris (VY CMa) is a red hypergiant star in the constellation Canis Major. It is about distant from Earth. It is one of the biggest known stars in the universe, and one of the most luminous of its type. 
VY Canis Majoris is 1,420 times bigger than the Sun. If placed at the center of the Solar System (where the Sun is), VY Canis Majoris's surface would extend beyond Jupiter's orbit. However, there is some differences in the estimates of how big it is. Other estimates of the radius make it bigger than the orbit of Saturn.
VY CMa is a single star, a "semiregular" variable with a period of about 2,001 days. It has an average density of 5 to 10 mg/m3.
When it dies it is expected to explode to a Supernova and then turn into a Black hole.