Sunday, 27 January 2019

Illuminating Spheroids

Twinkle Twinkle little star, how I wonder what you are????
Ever imagined what a Star is after high school?
Well it’s a fixed luminous point in the night sky that shines brightly miles away. These huge giant spheres are made up of very hot gases. These gases are mostly hydrogen and helium. These lustrous elements shine by fusing hydrogen into helium. Miles away from the earth, Stars appear to be so small. But actually they are much bigger than the Sun itself. Many stars also come in pairs called binary stars.
The life cycle of stars can be classified into 4 parts:
·         Birth
·         Main sequence
·         Red Giant
·         Collapse phase
The formation of a star begins with gravitational instability within a molecular cloud. Gravity forces the dust to come together. When more and more dust bunches up, gravity gets stronger.Thus increasing the temperature becoming and a protostar. Once the center has sufficient amount of heat, nuclear fusion will begin and a young star is born.The star in its youth (less than 10 million years old) is known as a Tauri star while those with greater mass are Herbig stars. The newly formed stars emit jets of superheated gases along their axis of rotation.
Stars spend about 90% of their existence fusing hydrogen into helium in high-temperature and high-pressure. Stars in this phase are said to be on the main sequence, and are called Dwarf stars. Our Sun, the closest star to the earth is also a dwarf star which is 4.5 billion years old. The time a star spends on the main sequence depends primarily on the amount of fuel it has and the rate at which it burns it. As stars exhaust their supply of hydrogen at their core, they start to fuse hydrogen from a shell outside the helium core.  This is when they are converted into Red Giants. Their outer layers expand and cool in this phase. Eventually the core of the star will start to make ions. This will cause the star to Collapse. The future of the star is depended upon its size. The average star will become a white dwarf star while the larger stars will create a huge nuclear explosion called a supernova.
Stars are not scattered randomly through space. They are gathered together into vast groups known as Galaxies. There are about 10 billion galaxies which can be observed. The number of stars in a galaxy on an average is 100 billion. This makes a huge count of Shiners altogether.
The largest star that we know of is called VY CanisMajoris while the smallest known star right now is OGLE-TR-122b, a red dwarf star that's part of a binary stellar system. 
Amazing right? Keep Shining and following, the stars and us!

Ketaki Kardile