Color-Magnitude Diagrams of Low-Mass Dwarfs in the Sagitta M71 (NGC 6838) Globular Cluster*

We can classify Globular Clusters (GCs) composed of objects like cataclysmic variables and compact binaries, which we can then use to determine the age and dynamic evolution of the universe. Observed clusters can be depicted in higher-resolution images, depending on the CCD used. CCD technologies present a variety of opportunities to model GCs. One of the main techniques for modeling GCs is generating a Color Magnitude Diagram, a method that uses stellar classification. CMDs find numerous potential applications in the areas of ultra-diffuse galaxies, GCs, and redshifts. However, there is still a lot of room for improvement in their utility. It is possible to enhance their properties by parameterizing the globular cluster denisty rating system. Moreover, modeling GCs with CMDs could facilitate improved chemical tagging in supernovae, which find many attractive applications in astronomy, such as building primordial models that could be replicated inside accelerators. 

This work's significant original contribution to knowledge is the preliminary hypothetical color-magnitude diagrams which were derived using the ds9 stellar catalog analysis package, SIMBAD, and model atmospheres from the standard MARCS. In order to derive a model for the color and magnitude of NGC 6838, we determined stellar brightness as a function of metallicity, rotation, age, and distance of M dwarfs and Algol-like binaries. We also sought to examine how a CCD which is tuned to the branch and main sequence stars of the M71 globular cluster might lead to further generalizations about the magnitude and evolution of Globular Clusters. Further investigations into the sensitivity of metallicity, stellar activity, circumstellar dust are needed in order to identify the extent of these residual effects on cluster representation via CMD.

Consistent with the use of r-g-i SDSS filters on the ProEM CCD, this work presents the initial results of a CMD model generated from spectra of 118 Sagittae. We also present the sky spectra map obtained with the 2.1-m Otto Struve Telescope. Magnitudes of M dwarfs, W Algol-like binaries, with SX Phoenicis blue stragglers are provided. Theoretical MIST isochrones for the color-temperature relations in M71 were of comparable accuracy.