Front

What are the key variables on the Hertzsprung-Russell diagram (H-R diagram)?

Back

Luminosity (brightness) and temperature.

Front

How is temperature represented on the H-R diagram?

Back

The horizontal axis represents the surface temperature of stars, decreasing from left to right.

Front

How is luminosity represented on the Hertzsprung-Russell diagram?

Back

The vertical axis represents luminosity (brightness), increasing from bottom to top.

Front

What units are used to measure temperature and luminosity on the Hertzsprung-Russell diagram?

Back

Temperature is measured in Kelvin (K), and luminosity is usually compared to the Sun's luminosity (L☉).

Front

What is the temperature range of stars on the Hertzsprung-Russell diagram?

Back

From about 3,000K (cool stars) to over 30,000K (hot stars).

Front

What is the luminosity range of stars on the Hertzsprung-Russell diagram?

Back

The range is from much dimmer than the Sun to several million times brighter.

Front

What are the main groups of stars on the Hertzsprung-Russell diagram?

Back

Main sequence stars, giants and supergiants, and white dwarfs.

Front

Where is the main sequence star located on the Hertzsprung-Russell diagram?

Back

A diagonal band from the upper left (hot, bright stars) to the lower right (cool, dim stars).

Front

Where are giants and supergiants located on the Hertzsprung-Russell diagram?

Back

Above the main sequence; they are cooler but very bright.

Front

Where is the white dwarf located on the HR diagram?

Back

In the lower left corner; they are hot but dim due to their small size.