The astrophysical parameters of four unstudied open star cluster candidates; Ivanov 2, 7, 9, and Harvard 9; are estimated for the first time using the PPMXL database. The stellar density distributions and color-magnitude diagrams for each cluster are used to determine the geometrical structure (cluster center, limited radius, core and tidal radii, the distances from the Sun, from the Galactic center and from the Galactic plane). Also, the main photometric parameters (age, distance modulus, color excesses, membership, total mass, relaxation time, luminosity and mass functions) are estimated.

Abstract
1. INTRODUCTION
2. PPMXL DATA EXTRACTION
3. DATA ANALYSIS
    3.1. Cluster’s Centers and Radial Density Profile
    3.2. The PPMXL Photometry
    3.3. Luminosity Functions
4. CONCLUSION
REFERENCES

• A. L. TADROSS(National Research Institute of Astronomy and Geophysics) CORRESPONDING AUTHOR
• R. BENDARY(National Research Institute of Astronomy and Geophysics)