Lenticular Galaxies

The lenticular galaxy type is in the middle between spiral and elliptical galaxies. They have a flat disk like a spiral galaxy, but with no spiral arms. Just like spiral galaxies, they have a bulge in its centre and they can be barred as well. In despite of their shapes, lenticular galaxies share similar properties with elliptical galaxies. Their interstellar medium -- that is, the gas between the stars inside the galaxy -- appears to be lost probably after a merger or tidal forces. They host ageing stars and they have very little star formation.

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