Exam 20: The Milky Waya Normal Spiral Galaxy

Imagine you discovered a barred spiral galaxy that was a "Milky Way twin" because of the size of the bulge and disk, the arrangement of the spiral arms, and other characteristics just like those in our galaxy.Then you measured its rotation curve and plotted the data as shown in the figure below.What would you conclude about this galaxy?

What evidence is there for dark matter existing in our galaxy? How does it compare to the dark matter content of other galaxies?

Describe, for each component of the Milky Way Galaxy labeled in the figure below, the typical heavy-element abundances found in that region, and what causes that region to have those abundances.

The Sun is located approximately

The Andromeda Galaxy is

The chemical composition of a star's atmosphere tells us

Spiral arms are

You find a star orbiting about the center of the galaxy at a distance of 15 kpc.Using the rotation curve in the figure shown below, estimate how much mass is enclosed within the orbit of that star.You can assume the star is on a circular orbit around the center of the Milky Way.

Describe two pieces of evidence that show that Sagittarius A* is a supermassive black hole.

If we found a star cluster at the edge of the disk of the Milky Way at a distance of 10 kpc from the center, and it orbited with a velocity of 250 km/s, what would be the total mass enclosed within this radius?

Where are the stars with the highest fraction of heavy elements found in the Milky Way?

Suppose that scientists in the future are able to observe a star orbiting the central region of the Andromeda Galaxy and find that it has an orbital period of 31 years and a semimajor axis of 4,500 AU.The mass of Andromeda's central black hole must then be around

Most cosmic rays are

X-ray observations indicate that around the Milky Way there may be an extended halo of

What are spiral arms, and what is thought to cause them?

Which regions of the Milky Way are the most likely to support star systems with habitable planets? Back up your answer with evidence-based reasoning.

Sagittarius A*, the radio source located at the center of our galaxy, is thought to be a

The most distant globular clusters are found in which part of the galaxy?

Open star clusters primarily inhabit which part of spiral galaxies?

Given that astronomers cannot see our Milky Way Galaxy's from the outside, how do they measure its rotation curve?