Construction of a Hertzsprung–Russell Diagram Using Gaia DR3 Data

This project constructs a stellar color–magnitude Hertzsprung–Russell (HR) diagram using real observational data from Gaia DR3.
The workflow includes:

• Querying and exporting Gaia catalog data using TOPCAT
• Cleaning data using parallax and photometric error filters
• Computing stellar distances and absolute G magnitudes
• Deriving the BP–RP color index
• Visualizing stellar populations using a hexbin density plot
• Overlaying a theoretical White Dwarf cooling sequence for interpretation

Key Features Identified in the Diagram

• Main Sequence — dense diagonal stellar population
• Red Giant Branch — luminous, cooler stars
• White Dwarf region & cooling trend — hot, faint stellar remnants

Technologies Used

• Python
• Pandas, NumPy, Matplotlib
• TOPCAT for data querying/export

Output Graph

The HR diagram is saved as gaia_hr_final.png