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Which of the following best describes dark matter? It is very large and invisible. Accretion is defined as: Gravity that pulls matter in a spiraling matter.
Astronomers believe that galaxies have spiral arms because galaxies rotate – or spin around a central axis – and because of something called “density waves.” A spiral galaxy’s rotation, or spin, bends the waves into spirals. Stars pass through the wave as they orbit the galaxy center.
An elliptical galaxy looks as if it is a giant star because it lacks the distinctive structure of a spiral galaxy, where the bulge is surrounded by a…
Spiral galaxies contain both old and young stars, as well as interstellar matter, and have typical masses in the range of 109 to 1012MSun. Our own Galaxy is a large spiral. Ellipticals are spheroidal or slightly elongated systems that consist almost entirely of old stars, with very little interstellar matter.
1 keV gaseous halos extending, in some cases, to well beyond 10re is strong evidence for the presence of extended dark matter in elliptical galaxies.
Most elliptical galaxies contain very little gas and dust because they had already formed.
Type c spiral galaxies
An ultra-faint collection of 1,000 stars orbiting the Milky Way is the most lightweight galaxy ever discovered, scientists say. The dwarf galaxy known as Segue 2 is bound together by a tiny clump of dark matter.
Elliptical galaxies contain very little gas and dust, and the gas that is present is very hot and diffuse. Consequently, there is no current star formation in elliptical galaxies. The stars in elliptical galaxies are old Population II stars.
In general, irregular galaxies contain large amounts of gas and dust, and can exhibit a significant degree of star formation activity. The closest galaxy to the Milky Way happens to be an irregular galaxy called the Canis Major Dwarf.
The Milky Way has two irregular “satellite” galaxies, called the Large and Small Magellanic Clouds.
Galaxies are classified by shape. There are three general types: elliptical, spiral, and irregular. Our Milky Way Galaxy is a spiral galaxy. Some spiral galaxies are what we call “barred spirals” because the central bulge looks elongated – like a bar.
Answer Expert Verified. Answer: Large collection of stars, gas, and dust held together by gravity.
Star cluster, 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. The two types are open (formerly called galactic) clusters and globular clusters.
What phrase best defines a star system? Stars appear brighter.