How Fast Do Stars Orbit in Different Galaxies?

[Bjarne]

1.
How fast are stars orbit speed in elliptical galaxies (from and to)

2.
How big differences are there typical between
Perigalacticon and Apogalacticon in a. elliptical galaxies and b. spiral galaxies?

 

[mfb]

1. It depends on the mass of the galaxies and the distance of the star. In addition, not all orbits are circular, the velocity can vary with time.
The sun has an orbital velocity of ~200km/s. While other stars have different speeds, it should give you some idea about the orders of magnitude involved.

2. There probably exists some study somewhere. I think the interesting graph would be two-dimensional, plotting both values at the same time (or semi-major axis and excentricity) for all stars and showing their density in this area.

 

[phinds]

Just another thing to think about: the stars closest into the super-massive black hole at the center of the milky way orbit around it at staggeringly high speeds relative to those far away from its influence.