Stars pass through a definite evolutionary sequence. With this reference, which among the following is a correct order?
Stars pass through a definite evolutionary sequence.
The first step in the formation of a star from gases is the Protostar. Protostar is formed by the gravitational contraction of gases present in the Galaxy. A Protostar is a highly condensed cloud of gases, mainly hydrogen and helium.
Second stage is Red Giants. The continued Nuclear fusion upset the overall equilibrium of the star and to readjust it star’s outer region expands while the core shrinks. Due to the large expansion of the outer shell, the star becomes very big, and its colour changes- to red.
Third Novae and Supernovae
A giant star phase may end in a Novae/
Supernovae stage. These are stars whose brightness increase suddenly by ten to twenty magnitudes or more due to a partial or outright explosion in the star. When brightness increases to 20 magnitudes or more, it is called a Supernovae.
A Novae/Supernovae explosion in a small star like our Sun (stars lighter than 1 .2 solar mass) may leave behind a very dense core of that state. A star of this size cools and contracts to become a White Dwarf.
A supernovae explosion in a star bigger than Sun but not more than twice as big, may leave behind an extremely dense, residual ‘core of that star, reaching a density of 1014 gms/cm3, known as Neutron Star.
A spinning neutron star emits radio waves and is called a Pulsar
A black hole is an object With such strong gravitational field that even light cannot escape from its surface. Black holes are formed from neutron stars after the Supernova explosions of big stars.
This question is a part of GKToday's Integrated IAS General Studies Module