Star Clusters

28.06.2024

Star Clusters

Why in the news?                        

Astronomers recently discovered five young star clusters, and possibly the oldest star clusters ever, born from the time when the Universe was an infant.

About Star Clusters:

• A Star cluster is either of two general types of stellar assemblages held together by the mutual gravitational attraction of its members, which are physically related through common origin.
• They are particularly useful to astronomers as they provide a way to study and model stellar evolution and ages.
• The two basic categories of stellar clusters are open clusters, also known as galactic clusters and globular clusters.
• In addition, groups called associations, made up of a few dozen to hundreds of stars of similar type and common origin whose density in space is less than that of the surrounding field, are also recognized.

Open (Galactic) Clusters:

• Open clusters are so named due to the fact that the individual component stars are easily resolved through a telescope.
• They are sometimes called galactic clusters due to their location on the dusty spiral arms on the plane of spiral galaxies.
• Stars in an open cluster have a common origin: they formed from the same initial giant molecular cloud.
• Open clusters contain from a dozen to many hundreds of stars, usually in an unsymmetrical arrangement.

Globular Clusters:

• Globular clusters contain several thousand to one million stars in a spherical, gravitationally-bound system.
• Located mostly in the halo surrounding the galactic plane, they comprise the oldest stars in the galaxy.
• There is little free dust or gas found in globular clusters, so no new star formation is taking place in them.
• Stellar densities within the inner regions of a globular cluster are very high compared with regions such as those around the Sun.

                                                                Source: Indian Express

Ques :- Consider the following statements with reference to the Star Clusters:

Statement-I

 They are stellar assemblages held together by the mutual gravitational attraction of their members.

Statement-II

 Stars in an open star cluster do not have a common origin as they are formed from different initial giant molecular clouds.

Which one of the following is correct in respect of the above statements?

A.Both Statement-I and Statement-II are correct, and Statement-II is the correct explanation for Statement-I.

B.Both Statement-I and Statement-II are correct, and Statement-II is not the correct explanation for Statement-I.

C.Statement-I is correct, but Statement-II is incorrect.

D.Statement-I is incorrect, but Statement-II is correct.

Answer C