This picture of the nebula around a rare yellow hypergiant star called IRAS 17163-3907 is the best ever taken of such a star, showing for the first time the double shell of dust around the central star. The star and its shells resemble an egg white around a yolk, leading to the nickname of Fried Egg Nebula.
Astronomers have studied VY Canis Majoris, a red supergiant star that is also classified as a hypergiant because of its very high luminosity, for more than a century. The star is located 5,000 light-years away. It is 500,000 times brighter and about 30 to 40 times more massive than the Sun. If VY Canis Majoris were at the center of our Solar System, its surface could extend to the orbit of Saturn. The star is also in the process of falling apart, and astronomers have learned that its gaseous outflows are more complex than originally thought.
The star has had many outbursts as it nears the end of its life, and the eruptions have formed loops, arcs, and knots of material moving at various speeds and in many different directions. The outermost material was ejected about 1,000 years ago, while a knot near the star may have been ejected as recently as 50 years ago
The typical red supergiant phase of a dying star lasts about 500,000 years as the massive star becomes a red supergiant that has exhausted the hydrogen fuel at its core. As the core contracts under gravity, the outer layers expand, the star’s diameter grows as much as 100 times larger, and it begins to lose mass at a higher rate. VY Canis Majoris has probably already shed about half of its mass, and it will eventually explode as a supernova.
This is a young super star cluster known as Westerlund 1. It’s the home of one of the largest stars yet found. Westerlund 1-26 is a red supergiant with a radius over 1,500 times that of our sun. Indeed, it’s sometimes referred to as a hypergiant star. If Westerlund 1-26 were at the center of our solar system, it would extend out beyond the orbit of Jupiter.
The Westerlund 1 cluster is relatively young in astronomical terms, around three million years old. The Sun is around 4.6 billion years old.