How can we determine the distance to the Galactic center?

In summary, the problem statement is about using "spectroscopic line shift of S2" and "its proper motion" to determine the distance and inclination of S2's orbit. The "spectroscopic line shift" is a measure of the star's velocity, while the "proper motion" is the star's apparent motion on the sky. By measuring both of these values over time, the unknowns can be solved for. The provided figure (c) shows the apparent orbit of S2.
  • #1
arcTomato
105
27
Homework Statement
We can use "spectroscopic line shift of S2" and "its proper motion", but I don't have any idea what dose this sentences mean.
please show me details!!
Relevant Equations
spectroscopic line shift
Problem Statement: We can use "spectroscopic line shift of S2" and "its proper motion", but I don't have any idea what dose this sentences mean.
please show me details!
Relevant Equations: spectroscopic line shift

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  • #2
The "spectroscopic line shift" is the shift in spectral line frequency due to the Doppler effect. It tells you the velocity of the star S2 towards or away from us in absolute terms, meaning in km/sec. The "proper motion" is the apparent motion of the star on the sky, which you can see in the right hand plot you supplied. It is an angular motion, so has units like arcseconds/year. There are two unknowns, the distance to the star, and the inclination of the orbit to the line of sight. If you have both measurements as a function of time, you can solve for both unknowns. Does this help?
 
  • #3
Hello!
phyzguy said:
There are two unknowns, the distance to the star, and the inclination of the orbit to the line of sight. If you have both measurements as a function of time, you can solve for both unknowns.
Please,Could you show me details how to solve??
I know the period , the velocity provided by "spectroscopic line shift" , and the apparent motion, right??
And, Is this Fig(c) the apparent orbit?
 
Last edited:

1. What methods are used to determine the distance to the Galactic center?

There are several methods that scientists use to determine the distance to the Galactic center. These include measuring the parallax of nearby stars, using the period-luminosity relationship of variable stars, and observing the motion of gas clouds in the Milky Way.

2. How does parallax help determine the distance to the Galactic center?

Parallax is the apparent shift in the position of an object when viewed from different angles. By measuring the parallax of nearby stars, scientists can calculate their distance from Earth, and then use this information to determine the distance to the Galactic center.

3. What are variable stars and how do they help determine the distance to the Galactic center?

Variable stars are stars whose brightness fluctuates over time. Scientists have discovered a relationship between the period of a variable star's brightness fluctuations and its intrinsic luminosity. By measuring the period of a variable star, scientists can determine its luminosity and then use this information to calculate its distance from Earth and, ultimately, the distance to the Galactic center.

4. How do observations of gas clouds in the Milky Way help determine the distance to the Galactic center?

Scientists can observe the motion of gas clouds in the Milky Way using telescopes and other instruments. By measuring the speed and direction of these gas clouds, scientists can calculate their distance from the Galactic center and use this information to determine the distance to the Galactic center.

5. What challenges do scientists face when trying to determine the distance to the Galactic center?

One of the main challenges scientists face is the vastness of space. The distances involved in measuring the distance to the Galactic center are incredibly large, making it difficult to accurately measure and calculate these distances. Additionally, there may be uncertainties or errors in the measurements and observations used to determine the distance. This is why scientists often use multiple methods and cross-check their results to ensure accuracy.

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