Student Project 3 - Stellar Characteristics
Download FTS images for this lesson here.
These are images of Star Clusters M29 and M39 in Cygnus, taken with the COWCAM (the 1Kx1K CCD camera mounted at prime focus of the 32” telescope at PMO) in 2001, using Red (R), Blue (B), and Green (V) color filters. The images are only 1.2 seconds, as the camera is so sensitive and we only wanted to image the stars in those clusters, not the background objects. The original image files are 5 meg apiece. Field of View (FOV) is about ½ degree.

Inquiry Claim example: Stars vary widely in color due to their chemistry.

This data is primarily made available to facilitate the classification of stars and thus to provide a study of stellar physical characteristics. In the case of a star, at relatively high temperatures, somewhat similar to an electric stovetop, the colors are primarily due to temperature differences. A hotter star emits more blue photons, cooler stars emit more red photons.
Many years ago, famous physicist Max Planck generated a well known equation that relates temperature to energy (color) of emitted light. We can use his equation (see an interactive graphical version at <>) to determine the “Color Index” of a star, the relative amounts of different energies, such as B-V, etc., which thus tells us the temperature of the star. If we plot a set of data about the colors and luminosities of a group of stars, such as in one of these clusters, we can find some family trends which can lead us to the age of the stars, and can also generate the well known Hertzsprung-Russell diagram that illustrates the classes of stars and their path of change in temperature, size, and luminosity over their lifespans.
Professor Bothun is developing a suite of activities to make best use of this data, but you can get a start on some of these analyses.







Image M29B10
Image M29V10
Image M29vregtob
Image M39B10
Image M39V10
Image M39vregtob
Image b reg to r
Image M101B120
Image M101R120
Image M101V120