Saturday, April 26, 2008

What Is VY Canis Majoris?

VY Canis Majoris ( VY CMa ) is a red hypergiant star located in the constellation Canis Major. It is the largest known star and also one of the most luminous known. It is located about 1.5 kiloparsecs or 5,000 light years from Earth. It's estimates the radius of VY CMa at 1800 to 2100 solar radii. To illustrate, if our Sun was replaced with VY Canis Major, its surface would extend to the orbit of Saturn. Assuming the upper size limit of 2100 solar radii, light would take more than 8 hours to travel around the star's circumference. VY CMa is approximately 26,000 times the radius of the Sun. Similarly if a human could walk on the sucgace of Canis Majoris - assuming a speed of 5 km/h (3 mph) for 8 hours a day the person would have to walk for 650,000 years to circle the star ( compared with 2 years 11 months to complete the same task on Earth, and 310 years 7 months on the Sun )