Do you think that Sun is the largest star of this Universe? Think again. VY Canis Majoris (VY CMa) is currently the largest known star and also one of the most luminous. Even the most seasoned fans of deep astronomy are baffled with the size representation of the giant star. Located in the constellation Canis Major, it is a red hypergiant, between 1800 and 2100 solar radii, 8.4–9.8 astronomical units in radius, 3.063 billion km or 1.7 billion miles in diameter, and about 1.5 kiloparsecs (4,900 light years, 4.6×1016km or 2.9×1016mi) away from Earth. The actual size of VY Canis Majoris is 3,063,500,000,000 m or 3.06 Tm (Terametre), giving it an average density of 0.000005 to 0.000010 kg/m3. Professor Roberta M Humphreys, while discussing luminosity fo VY Canis Majoris, lists the star's spectral luminosity at 5.6 x 10^5. Although this number might not mean much at first glance but the fact that VY Canis Majoris is so bright that it is consuming itself will bring home the point. A star consumes its own mass to continue spreading light and radiation to the far reaches of the galaxy as it burn brighter and brighter. It is because of this reason that, this star has actually released over half its mass already. A lot of energy is released with the spread of all this light. This star releases more energy in a second then the output of the Sun in an entire year.

VY Canis Majoris

Size comparison between Sun and the largest star University of Minnesota professor Roberta M. Humphreys estimates the radius of VY CMa at 1,800 to 2,100 solar radii. If the Earth were to be represented by a sphere one centimeter (0.39) in diameter, the Sun would be represented as a sphere with a diameter of 109 centimeters (3½ ft.), at a distance of 117 meters. At these scales, VY Canis Majoris would have a diameter of approximately 2.3 kilometers (1.43 mi.), assuming the upper limit estimate of its radius.

More, and larger, discoveries await as humanity delves deeper into the depths of space but as the largest known star,VY Canis Majoris still dominates the celestial arena when compared to other hypergiants.