VY Canis Majoris – too small 4u?

VY Canis Majoris (VY CMa) is a red hypergiant star located in the constellation Canis Major. At between 1800 to 2100 solar radii (approx 2,505,600,000 to 2,923,200,000 km across or 1,556,534,837 to 1,816,267,995 miles), it is the largest known star and also one of the most luminous known.

It is located about 1.5 kiloparsecs (4.6×10¹⁶ km) or about 4,900 light years away from Earth. Unlike most hypergiant stars, which occur in either binary or multiple star systems, VY CMa is a single star. It is categorized as a semiregular variable and has an estimated period of 2000 days.

VY Canis Majoris is the largest known star (in the Milky Way).University of Minnesota professor Roberta M. Humphreys estimates the radius of VY CMa at 1,800 to 2,100 solar radii. To illustrate, if Earth’s Sun were replaced by VY Canis Majoris, its radius might extend beyond the orbit of Saturn (about 9 AU). Assuming the upper size limit of 2100 solar radii, light would take more than 8 hours to travel around the star’s circumference, compared to 14.5 seconds for the Sun.

It would take over 7,000,000,000,000,000 (7×10¹⁵ or 7 quadrillion) Earths to fill the volume of VY Canis Majoris.

If the Earth were to be represented by a sphere 1 cm in diameter, the Sun would be represented as a sphere with a diameter of109 cm, at a distance of 117 meters. At these scales, VY Canis Majoris would have a diameter of approximately 2.3 km, assuming the upper limit estimate of its radius.