Question

A star located off the main sequence indicates what?

Answer 1

A star off the main sequence has usually used up its Hydrogen.

Explanation:

Main sequence stars are in hydrostatic equilibrium and are fusing Hydrogen into Helium and other elements by fusion processes.

When a star's fusible nuclei become exhausted the star falls off the main sequence.

Older stars go through an giant stage which takes them off the main sequence.

Smaller older stars become white dwarfs which are also off the main sequence.

Every star follows the main sequence in its youth when it has a plentiful supply of Hydrogen. The more massive the star, the less time it is main sequence.