![]() Mutchler (Space Telescope Science Institute, Baltimore, USA), R. Kaviraj (Imperial College London and University of Oxford, U.K.), J. Crockett (University of Oxford, U.K.), S. Due to their very low rate of star formation and their populations of old, red stars, elliptical galaxies are sometimes colloquially referred to as ‘red and dead’ by astronomers.Įlliptical Galaxy. Therefore, it seems likely that elliptical galaxies are largely populated by stars that formed within active spiral galaxies. Whilst spiral galaxies have rich reservoirs of the dust and gas that fuel star formation, elliptical galaxies appear to have virtually exhausted that fuel, and so there is very little raw material for the formation of new stars. The typical ages of the stellar populations of elliptical and spiral galaxies provide evidence for this theory, because the stars in elliptical galaxies are typically much older and redder than those in spiral galaxies. O’Connell (University of Virginia, Charlottesville, USA), and the WFC3 Scientific Oversight CommitteeĬurrent thinking amongst astronomers is that most elliptical galaxies formed from the collisions and subsequent mergers of spiral galaxies. Kaviraj ( Imperial College London and University of Oxford, U.K.), J. Crockett ( University of Oxford, U.K.), S. They typically contain a much greater proportion of older stars than spiral galaxies do. In fact, Hubble just used those names to indicate the differences in structure between elliptical and spiral galaxies, and he himself was not sure how the different types of galaxies evolved.Įlliptical galaxies have an even, ellipsoidal shape. There is a common misconception that astronomers used to think that elliptical galaxies were the evolutionary forerunners to spiral galaxies, because Hubble himself referred to elliptical galaxies as ‘early-type’ and spiral galaxies as ‘late-type’. ![]() Elliptical galaxies are usually found in galaxy clusters. Elliptical galaxies have a smooth ellipsoidal or spherical appearance, and they have far less structure than spiral galaxies do. They typically contain a much greater proportion of older stars than spiral galaxies do.įour classes are used to classify galaxies: spiral barred spiral elliptical and irregular. O’Connell (University of Virginia, Charlottesville, USA), and the WFC3 Scientific Oversight Committee What Is an Elliptical Galaxy?Įlliptical galaxies have an even, ellipsoidal shape. ![]() ![]()
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