Question about extragalactic stellar motion

In summary, there is currently no specific model for the motion of extragalactic stars passing within one or two galactic radii of the Milky Way on hyperbolic transits. Most hypervelocity stars were ejected from the Milky Way and extragalactic stars that were ejected from other galaxies are extremely rare. The distance to these stars is usually listed with an error range, making distance measurements suspicious. Overall, there is no reason to believe that these stars deviate from Newton or Einstein's laws of motion.
  • #1
Prez Cannady
21
2
TL;DR Summary
Looking for a model--any model but one in particular--of extragalactic stellar motion.
We have direct mass models of stellar motion inside of galaxies (basically, find a happy medium between a sphere and a disc). And of course dark matter corrections to explain the deviation between model and observation.

Is there any pattern at all to the motion of extragalactic stars passing within one or two galactic radii of Milky Way on hyperbolic transits?
 
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  • #2
Prez Cannady said:
Summary:: Looking for a model--any model but one in particular--of extragalactic stellar motion.

Is there any pattern at all to the motion of extragalactic stars passing within one or two galactic radii of Milky Way on hyperbolic transits?

couldnt even find any extragalactic stars that fit your idea. I went through a large list of specific extragalactic ( to the Milky Way) stars
and all but 1 or 2 were associated with other galaxies

So, what stars did you have in mind ?
 
  • #3
I have not heard of any reason to believe they deviate from Newton or Einstein.

The distance to stars is usually listed with an error range. If the star in question is 2 galactic radii away from us distance measurements are very suspicious. A single star's motion can be caused but a wide variety of factors.

Most hypervelocity stars were ejected from the Milky Way. Extragalactic stars that were ejected from some other galaxy but did arrive here are going to be extremely rare. In a few billion years when Milky Way and Andromeda are about to merge they will temporarily become more common.
 

1. How do we measure the motion of stars in other galaxies?

We can measure the motion of stars in other galaxies using a technique called spectroscopy. This involves analyzing the light emitted by the stars and looking for shifts in the wavelength, which can indicate movement towards or away from us.

2. What causes stars in other galaxies to move?

The motion of stars in other galaxies is primarily caused by the gravitational pull of other objects, such as other stars, gas clouds, and dark matter. The distribution of these objects can affect the overall motion of stars in a galaxy.

3. What is the significance of studying extragalactic stellar motion?

Studying extragalactic stellar motion can provide us with valuable information about the structure and dynamics of galaxies. It can also help us understand the evolution of galaxies and the role of dark matter in shaping their motion.

4. Can we observe changes in extragalactic stellar motion over time?

Yes, we can observe changes in extragalactic stellar motion over time. This is known as proper motion and can be measured by comparing images of the same galaxy taken at different times. However, these changes are usually very small and require precise measurements to detect.

5. How does the motion of stars in other galaxies compare to our own galaxy?

The motion of stars in other galaxies can vary greatly, depending on the size, shape, and composition of the galaxy. Some galaxies may have very orderly, circular motion, while others may have more chaotic and irregular motion. Our own galaxy, the Milky Way, has a mix of both types of motion.

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