Hertzsprung-Russell (H-R) Diagrams model simulates Hertzsprung-Russell (HR or H-R) diagram for groups of stars. The diagram is a scatter plot of steller luminosity vs. stellar temperature. The luminosity of stars is proportional to the star's radius squared and its temperature to the fourth power, and for Main Sequence stars, their luminosity is also proportional to their mass to the 3.5 power. Since the range of stellar luminosities and stellar temperatures is so large, the plot uses a log-log scale. The diagram is a way to understand stellar evolution.

Controls
1. R/R_S Slider: changes the radius of the star (relative to the radius of Sun).
2. T Slider: changes the temperature of the star (in Kelvin).
3. Show Nearby Stars Checkbox (under the Change Stars Menu): displays nearby stars in H-R diagram.
4. Show Bright Stars Checkbox (under the Change StarsMenu): displays bright stars in H-R diagram.
5. Show Blackbody Curve Checkbox (under the Additional Views Menu): displays the blackbody spectrum.
6. Show Star Checkbox (under the Additional Views Menu): displays the star.
7. Reset button: resets the simulation to the original parameters.

Requirements:
* Java

The license of this software is Freeware, you can free download and free use this graphing software.