How is the Final Velocity of Star Movements Calculated?

• lenfromkits
In summary, when calculating space velocities of stars, the final velocity is determined by combining the radial and proper (tangential) motions. This is done by adding the two vectors together, as seen in the example of Bernard star with a tangential velocity of 90 and a radial velocity of 111, resulting in a space velocity of 142. However, some argue that there should be a relativistic component, as used in the transverse Doppler shift calculation, when adding these two vectors together.
lenfromkits
When calculating the space velocities of stars by combining what we see of both their radial and proper (tangential) motions, how is the final velocity determined?I don't believe they just add these two vectors together do they? Do they make use of the transverse Doppler shift calculation here?

Last edited:
For instance, apparently Bernard star has a tangential velocity of 90 and a radial of 111. Using plain pythagorans, this works out to 142 in space velocity. (see http://en.m.wikipedia.org/wiki/Proper_motion?wasRedirected=true)

why are these two vectors just added together so simply like this when there ought to be a relativistic component to it as used in the transverse Doppler shift calc?

1. What is the angle of star proper movement?

The angle of star proper movement is the direction of the apparent motion of a star across the sky as observed from Earth. It is measured in degrees and is influenced by the star's proper motion, which is its actual motion through space.

2. How is the angle of star proper movement calculated?

The angle of star proper movement is calculated by measuring the star's position in the sky at two different times and calculating the change in its position. This change is then converted into an angle measurement.

3. What causes a star's proper motion?

A star's proper motion is caused by its actual movement through space. This can be influenced by a variety of factors, including its own motion, gravitational interactions with other stars and objects, and the rotation of the Milky Way galaxy.

4. Can the angle of star proper movement change over time?

Yes, the angle of star proper movement can change over time due to the star's own motion, as well as any external influences. However, these changes are typically very small and may not be noticeable within a human lifetime.

5. How is the angle of star proper movement related to a star's distance?

The angle of star proper movement is not directly related to a star's distance. However, a star's distance can affect its apparent proper motion, as closer stars will appear to have a larger angle of proper movement compared to more distant stars with the same actual motion.

• Special and General Relativity
Replies
28
Views
2K
• Astronomy and Astrophysics
Replies
6
Views
1K
• Aerospace Engineering
Replies
9
Views
1K
• Astronomy and Astrophysics
Replies
12
Views
1K
• Introductory Physics Homework Help
Replies
0
Views
314
• Cosmology
Replies
30
Views
4K
• Differential Geometry
Replies
29
Views
2K
• Cosmology
Replies
2
Views
1K
• Mechanics
Replies
6
Views
1K
• Astronomy and Astrophysics
Replies
4
Views
2K