GALAXIES

SPIRAL GALAXIES

• Spiral galaxies are galaxies whose visible stars take on
• a spiraling pinwheel shape.
• Though the stars and other visible material contained
• in such a galaxy lie mostly on a plane, the majority of mass
• in spiral galaxies exists in a roughly spherical halo of dark matter.

ELLIPTICAL GALAXIES

• These galaxies have an ellipsoidal profile,
• giving them an elliptical appearance regardless
• of the viewing angle.
• Their appearance shows little structure and they
• typically have relatively little interstellar matter.

PECULIAR GALAXIES

• Peculiar galaxies are galactic formations that develop
• unusual properties due to tidal interactions with other galaxies.
• An example of this is the ring galaxy, which possesses a ring-like structure
• of stars and interstellar medium surrounding a bare core.

LENTICULAR GALAXIES

• A lenticular galaxy is an intermediate form that has
• properties of both elliptical and spiral galaxies.
• These are categorized as Hubble type S0, and they
• possess ill-defined spiral arms with an elliptical halo of stars.

DWARF GALAXIES

• These galaxies are relatively small when compared with
• other galactic formations, being about one hundredth
• the size of the Milky Way, containing only a few billion stars.