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In the nucleus of a spiral galaxy the most stars are old population II stars, and there is no star formation (which occurs in the spiral arms). Why?
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Thanks.
Some clarifications ... the 'nucleus' of a galaxy - spiral or otherwise - isn't a particularly well defined region. Historically, it meant something like 'the bright point we see on images, at the apparent centre of the galaxy; it's too small to resolve, so we don't know what's really there' Some astronomers made (then) very tricky observations of the radial brightness and colour profiles of the central few arcsec of nearby galaxies; these days the VLT, Hubble, etc make nice images of what older astronomers could 'see' only as a fuzzball. The central part of a spiral is the 'bulge', which varies in size from tiny (in Sc spirals) to huge (in Sa and lenticulars); it is the bulge which is comprised of Population II stars.hellfire said:In the nucleus of a spiral galaxy the most stars are old population II stars, and there is no star formation (which occurs in the spiral arms). Why?
Thanks.
Spiral galaxies form from a combination of gravitational collapse and rotational motion. As a giant cloud of gas and dust collapses under its own gravity, it begins to rotate, forming a disk. This disk then undergoes further collapse and fragmentation, leading to the formation of spiral arms.
The distribution of stars in a spiral galaxy is primarily determined by the structure of the galaxy's spiral arms. These arms are made up of dense regions of gas and dust, which act as nurseries for new stars to form. As these new stars are born, they are pulled towards the center of the galaxy by gravity, contributing to the overall distribution of stars.
Stars form in spiral galaxies through a process called accretion. As gas and dust collapse under their own gravity, they become denser and hotter, eventually reaching a point where nuclear fusion can occur. This process releases energy and causes the gas to shine brightly as a new star.
No, not all spiral galaxies are the same. There are two main types of spiral galaxies: barred and unbarred. Barred spiral galaxies have a distinct bar-shaped structure in the center, while unbarred spiral galaxies do not. Additionally, the size and shape of spiral arms can vary greatly between different spiral galaxies.
Yes, spiral galaxies can evolve over time through interactions with other galaxies. As spiral galaxies come into close contact with one another, their gravitational interactions can cause them to merge, forming a new type of galaxy. This process can also disrupt the structure of spiral arms and change the distribution of stars in a galaxy.