Ages of Stars from CMD: The Accuracy of CMD vs. Photometry Explained

  • Context: Graduate 
  • Thread starter Thread starter randa177
  • Start date Start date
Click For Summary

Discussion Overview

The discussion revolves around the accuracy of determining the ages of star clusters using color magnitude diagrams (CMD) compared to photometry. Participants explore the reasons why CMDs might provide more reliable age estimates and seek clarification on the methodologies involved.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants question why CMDs are preferred over photometry for age determination of star clusters.
  • There is a suggestion that CMDs (Hertzsprung–Russell diagrams) provide more accurate ages due to their ability to incorporate the evolutionary state of stars.
  • One participant notes that while photometry is used to obtain color indices, the integrated colors of a cluster may not yield accurate age information.
  • Another participant expresses uncertainty about the question and seeks further clarification on how ages are derived from CMDs.
  • Some participants emphasize the need for additional parameters such as metallicity and mass to achieve accurate age estimates from CMDs.

Areas of Agreement / Disagreement

Participants express varying levels of understanding regarding the advantages of CMDs over photometry, and there is no consensus on the specific methodologies for age determination from CMDs. The discussion remains unresolved with multiple viewpoints presented.

Contextual Notes

Participants mention the importance of definitions and clarify that CMD is not a universally recognized abbreviation, which may affect the clarity of the discussion.

Who May Find This Useful

Individuals interested in astrophysics, particularly in stellar evolution, star cluster analysis, and the methodologies used in astronomical observations.

randa177
Messages
90
Reaction score
1
why is getting the age from CMD more accurate than getting it from photometry?
 
Astronomy news on Phys.org
I mean ages of start clusters!
 
Why no one answered my question? Does it make sense?
Why are we requiring color magnitude diagrams to get ages.. Why are they the best?
 
CMD isn't a very common abbreviation, most people would say HR diagram.
Do you mean - how to get the age of stars from a color magnitude (ie Hertzsprung–Russell) diagram?
 
mgb_phys said:
CMD isn't a very common abbreviation, most people would say HR diagram.
Do you mean - how to get the age of stars from a color magnitude (ie Hertzsprung–Russell) diagram?

Actually I am reading papers about large magelanic cloud, and it always mentions that getting the age using CMD (H-R diagram) is more accurate than using photometry. why CMDs give the only truly accurate ages for star clusters?
 
Not sure I understand the question. You use photometry to get the color index of the star. Then plotted on the HR diagram gives you the age (or at least the evolutionary state of the star) for an accurate age you would also need to know metalicity and mass.
 
mgb_phys said:
Not sure I understand the question. You use photometry to get the color index of the star. Then plotted on the HR diagram gives you the age (or at least the evolutionary state of the star) for an accurate age you would also need to know metalicity and mass.

Yes, that's right, but that uses the photometry of each star in the cluster, not the color/magnitude of the whole cluster, because the magnitude and integrated colors for a cluster as a whole doesn't give very accurate information... Oh, wait I think I've just answered my original question! ... i got confused too now!
 
Hi,
I just wanted to let you know that I was right about the reason CMD (HR diagram)give most accurate ages for stellar clusters.
But can anyone let me know HOW we get the ages from CMDs (H-R diagrams)?
 

Similar threads

Undergrad Is It Possible to Do Photometry Without Using a CCD?
  • · Replies 3 ·
Replies
3
Views
2K
Shutting down Windows 10 from CMD takes more time than usual....
  • · Replies 9 ·
Replies
9
Views
3K
Undergrad Transit Photometry: Questions about Detecting Exoplanets
  • · Replies 5 ·
Replies
5
Views
2K
Undergrad Calculating Proportional Luminosity of Fictitious Star
  • · Replies 11 ·
Replies
11
Views
3K
Undergrad J0524-0336, surprisingly high Li concentration
  • · Replies 2 ·
Replies
2
Views
3K
Undergrad Lateral offset from a centered star as measured at the focal plane
  • · Replies 3 ·
Replies
3
Views
1K
High School Forming Stars/ Brown Dwarfs by photo-erosion
  • · Replies 2 ·
Replies
2
Views
2K
Graduate Strong Progenitor Age Bias in Supernova Cosmology
  • · Replies 30 ·
2
Replies
30
Views
7K
Undergrad Why does the core collapse happen so fast in a supernova?
  • · Replies 3 ·
Replies
3
Views
4K
Undergrad Nuclear reactions in the Sun and other topics on stars
  • · Replies 49 ·
2
Replies
49
Views
6K