AM 0644-741, also known as the Lindsay-Shapley Ring, is an unbarred lenticular galaxy, and a

ring galaxy A ring galaxy is a galaxy with a circle-like appearance. Hoag's Object, discovered by Art Hoag in 1950, is an example of a ring galaxy. The ring contains many massive, relatively young blue stars, which are extremely bright. The central region co ...

, which is 300 million light-years away in the southern constellation

Volans Volans is a constellation in the southern sky. It represents a flying fish; its name is a shortened form of its original name, Piscis Volans. Volans was one of twelve constellations created by Petrus Plancius from the observations of Pieter Dirk ...

Properties

Formation

The yellowish nucleus was once the center of a normal spiral galaxy, and the ring which currently surrounds the center is 150,000

light years A light-year, alternatively spelled light year, is a large unit of length used to express astronomical distances and is equivalent to about 9.46 trillion kilometers (), or 5.88 trillion miles ().One trillion here is taken to be 1012 ...

in diameter. The ring is theorized to have formed by a collision with another galaxy, which triggered a

gravitational In physics, gravity () is a fundamental interaction which causes mutual attraction between all things with mass or energy. Gravity is, by far, the weakest of the four fundamental interactions, approximately 1038 times weaker than the stron ...

disruption that caused dust in the galaxy to condense and form stars, which forced it to then expand away from the galaxy and create a ring.

Physical characteristics

The ring is a region of rampant star formation dominated by young, massive, hot blue stars. The pink regions along the ring are rarefied clouds of glowing

hydrogen gas Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-toxic, a ...

that is fluorescing as it is bombarded with strong ultraviolet light from the blue stars.

Future of the ring

Galactic simulation models suggest that the ring of AM 0644-741 will continue to expand for about another 300 million years, after which it will begin to disintegrate.

References

{{DEFAULTSORT:AM 0644-741 Ring galaxies Unbarred lenticular galaxies Volans 019481 34-11 06443-7411