Most spiral galaxies consist of a flat, rotating disk containing stars, gas and dust, and a central concentration of stars known as the bulge. These are often surrounded by a much fainter halo of stars, many of which reside in globular clusters.
Do spiral galaxies have stars?
Do stars form in spiral galaxies?
The spiral arms in spiral galaxies are one type of environment where gravity is pushing gas and dust to form stars more efficiently than in other parts of a spiral galaxy. This is why you see more star forming regions and collections of young stars (open clusters) in spiral arms than in other parts of a spiral galaxy.
How many stars are in a spiral galaxy?
Estimate of stars varies from 200 billion to 400 billion. Milky way is a barred spiral.
Do spiral galaxies have billions of stars?
Spiral galaxies have lots of gas and dust and lots of young stars. Other galaxies are egg-shaped and called elliptical galaxy. The smallest elliptical galaxies are as small as some globular clusters.
What type of stars are in spiral galaxies?
Spiral Galaxies It is dominated by young, blue Population I stars. The central bulge is devoid of gas and dust. As you might expect, the bulge is composed primarily of Population II stars.
Where is star formation in spiral galaxies?
spiral arms The final aspect of the formation of spiral galaxies is the on-going star formation evident in their thin disks. This star formation is usually on the leading edge of the spiral arms where the cold gas of the thin disk is compressed, and provides unequivocal evidence for on-going secular evolution in thin disks.
Why do spiral galaxies have arms?
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.
How do stars move in a spiral galaxy?
This strange behavior may be due to perturbation caused by the central bar and spiral arms of our Galaxy, forcing stars to leave their normal circular course and take an outward path. … Due to gravity, the spiral arms move through the disk in the form of density waves.
Where are stars formed in a spiral galaxy?
spiral arms The final aspect of the formation of spiral galaxies is the on-going star formation evident in their thin disks. This star formation is usually on the leading edge of the spiral arms where the cold gas of the thin disk is compressed, and provides unequivocal evidence for on-going secular evolution in thin disks.