Estimating relative distances for star clusters

In summary, when estimating the relative distances of star clusters, one can use either their angular size or apparent brightness. However, the advantage of measuring angular diameter is that it is not affected by external factors, whereas measuring brightness requires making assumptions and correcting for interstellar reddening.
  • #1
randa177
91
1
If star clusters were all about the same physics size, how could one estimate their relative distances?
 
Astronomy news on Phys.org
  • #2
Either by measuring their angular size or apparent brightness.
 
  • #3
would the distances determined geometrically give the same result as those determined photometrically (using stellar brightness relation)?
 
  • #4
If they were really the same physical diameter then the advantage of measuring their angular diamter is that it isn't affected by anything else ( assuming it is large enough to be detected above atmospheric seeing)
The problem with measuring brightness is that you have to make assumptions and correct for the absorbtion and re-emmision from the space in between (Interstellar reddening).
 

1. How do scientists estimate the distance of star clusters?

Scientists use a method called parallax to estimate the distance of star clusters. This involves measuring the apparent shift in position of a star when viewed from different points on Earth's orbit around the sun. The greater the shift, the closer the star cluster is to Earth.

2. How accurate are these distance estimates?

The accuracy of distance estimates for star clusters depends on the precision of the measurements taken and the distance of the cluster. For nearby clusters, parallax measurements can be accurate within a few percentage points. For more distant clusters, other methods such as spectroscopy and photometry are used, which can have uncertainties of 10-20%.

3. Why is it important to accurately estimate the distance of star clusters?

Accurate distance estimates for star clusters are important for understanding the size and structure of our galaxy, as well as the overall scale of the universe. They also help scientists determine the ages and properties of stars within the cluster, which can provide valuable insights into the formation and evolution of galaxies.

4. Can star clusters be used as standard candles for measuring distances in the universe?

Yes, some types of star clusters, such as globular clusters, have a consistent brightness and can be used as standard candles for distance measurements. However, not all star clusters are suitable for this purpose, as their brightness can vary depending on their age and composition.

5. Are there any limitations to using star clusters for distance estimation?

One limitation of using star clusters for distance estimation is that they can only provide accurate measurements within a certain range. For example, parallax measurements can only be used for nearby clusters, while other methods are needed for more distant clusters. Additionally, the accuracy of distance estimates can be affected by factors such as dust and gas in the line of sight, and the variability of stars within the cluster.

Similar threads

Replies
2
Views
1K
  • Astronomy and Astrophysics
Replies
11
Views
1K
Replies
6
Views
797
  • Astronomy and Astrophysics
Replies
26
Views
2K
Replies
11
Views
2K
Replies
1
Views
552
  • Astronomy and Astrophysics
Replies
1
Views
822
  • Astronomy and Astrophysics
Replies
1
Views
1K
Replies
1
Views
786
  • Astronomy and Astrophysics
Replies
0
Views
813
Back
Top