In our observable universe there are innumerable stars, planets, galaxies, nebulae,black holes, etc. Out of all of these some are very small and some are extremely large. When we compare things to stars many of them are even bigger than sun. One of them is the great Stephenson 2-18. The biggest and one of the brightest stars in the universe.
Stephenson 2-18 also known as Stephenson 2 DKF 1 or RSGC2-01. Stephenson 2-18 is a red super giant or red hyper giant. It is located in the constellation of Scutum which lies in the open cluster Stephenson 2. It is 5.8 kiloparsecs away from the earth in the Scutum Centaurus Arm of the Milky Way galaxy. The age of Stephenson 2-18 is around is 11 to 20 million years. This age indicates that Stephenson 2-18 is a young star compared to many others in the galaxy.
Stephenson
2-18's estimated temperature 3200 K .i.e. is below the Hayashi limit, a
threshold for hydrostatic equilibrium in stars. This suggests it may not be
stable, a rare condition for a star of its apparent size. Stephenson
2-18's composition is primarily hydrogen and helium, like most stars, but as a
red supergiant, it also contains heavier elements such as lithium, carbon,
nitrogen, oxygen, neon, silicon, and iron. These heavier elements are created
through nuclear fusion in the star's core and outer layers.
Its
history revolves back in the 1990, when astronomer Charles Stephenson
discovered the Stephenson 2-18 while studying the cluster Stephenson 2 in the
scutum constellation. This star depicted itself as a very bright and an unusual
object. Some observations noticed the infrared light which made it clear that
it might be a red super giant or a red hyper giant.
Today
Stephenson 2-18 is recognised as the largest and brightest star in the
universe. This is the largest ever found dwarf found in universe. Stephenson is
so massive that our sun looks like a microscope in front of it. Stephenson 2-18
has a diameter of about 3 billion kilometers, which is approximately 2,150
times the diameter of the Sun. About 8 to 10 million suns can fit in Stephenson
2-18.
A
clear single image of the star was first captured in 2007 by the 2MASS survey
camera at Cerro Tololo Inter-American Observatory. Stephenson’s death estimates
that it would explode into a massive supernova or directly turn into a giant
black hole in the next few million years.
By, Aarya
Shah.
Batch 28.