Who were Enjar Hertzsprung and Henry Russell?

Answer 1

Enjar Hertzsprung lived in 1873-1967 and Henry Russell lived in 1877-1957. They were scientists who worked separtely. They found the same answer about the temperature and color of stars. The diagram that they made is called the Hertzsprung-Russell diargram. It shows the connection between surface temperature and color.
The discoverers of the famous Hertzsprung-Russel diagram (HR diagram), which turned out to be an important tool for the analysis of stars.

Answer 2

Ejnar Hertzsprung was a Danish astronomer who developed the Hertzsprung-Russell diagram, a tool used to categorize stars based on their luminosity and temperature. Henry Norris Russell, an American astronomer, further refined the diagram and collaborated with Hertzsprung on stellar classification.