What can be Determined from Colour-Colour Diagrams?

[Ricky116]

Hi,

I have a colour-colour (that is, V-R against B-V) diagram of a young open cluster, and I was wondering if anyone has any suggestions on any information that can be gleaned from such a diagram? I have searched the internet and these forums to no real avail.

There is a clear linear line through the diagram with many stars on either side, perhaps there is a standard V-R/B-V correlation my observations can be compared against? Would it make sense to compare my diagram with that found from Landolt's data: http://brucegary.net/photometry/V-R.htm ?

If anyone could help me begin to interpret the diagram, or provide me with a link to actual practical analysis I could utilise it would be much appreciated.

Thanks.

 

[Radrook]

Here are some links that might prove useful.

Interpretation of the colour-colour diagram of M92
http://adsabs.harvard.edu/full/1970MNRAS.149..179B

Color-Color Analysis of GLIMPSE Point Sources

http://www.astro.wisc.edu/~daniel/

Color Magnitude Diagram of Cluster M67 -
http://astronomyonline.org/Astrophotography/CMDDiagram.asp

COLOR-MAGNITUDE DIAGRAMS
ANALYSIS
Color-color and color-magnitude diagrams were analyzed
with the help of a software...

http://www.astro.iag.usp.br/~iaus266/Posters/pCosta-Caetano.pdf

 

[vociferous]

You can compare them to stellar models as well as other clusters. One thing that you might be able to estimate from them is metalicity and other factors that affect the star's effective temperature. If you plot an idea blackbody on the diagram you can see how and where the temperature differs.

 

[Ricky116]

Thankyou very much, Radrook and vociferous.

 

[pmacias]

From a colour-colour diagram, several things can be determined about a group of stars or a young open cluster. Firstly, the colour-colour diagram can provide information about the temperature of the stars. The V-R and B-V colours are related to the stars' surface temperature, with hotter stars appearing bluer and cooler stars appearing redder. By plotting the colours of the stars on the diagram, we can determine the overall temperature range of the stars in the cluster.

Additionally, the position of the stars on the diagram can also reveal their age. Younger stars tend to be hotter and bluer, while older stars are cooler and redder. By comparing the colour-colour diagram of the open cluster with that of other known clusters of different ages, we can estimate the age of the cluster in question.

The linear line that you have observed through the diagram is known as the main sequence. This line represents the majority of stars in the cluster and provides information about the stars' mass and luminosity. By comparing the position of the main sequence in your diagram with that of other clusters, you can determine the mass and luminosity of the stars in your cluster.

The comparison with Landolt's data can also be useful in determining the accuracy of your observations and measurements. If your diagram aligns closely with Landolt's data, it provides confidence in your results.

In summary, a colour-colour diagram can provide valuable information about the temperature, age, and mass/luminosity of stars in a young open cluster. By comparing your diagram with data from other sources, you can further refine your analysis and interpretation. I hope this helps in your research.