Final answer:
The H-R diagram shows a star's luminosity and surface temperature, and indirectly its stellar evolution stage, mass, and radius. Age of star clusters and surface gravity can also be deduced. However, properties like magnetic field strength and number of planets are not visible on the H-R diagram.
Step-by-step explanation:
The H-R (Hertzsprung-Russell) diagram is a graphical tool used in astrophysics to depict the relationship between a star's luminosity and its surface temperature. Besides these primary properties, the H-R diagram also indirectly shows other properties of stars. One can see the stellar evolution stage on the H-R diagram since it shows where different types of stars like main-sequence stars, giants, supergiants, and white dwarfs are located. Additionally, since most main-sequence stars follow a predictable pattern where their luminosity and temperature correlate with mass and radius, we can infer approximate values for these properties as well.
For instance, when looking at an H-R diagram:
- The age of a star cluster can be deduced by looking at where its stars fall off the main sequence, known as the 'turnoff point.' The longer a star remains on the main sequence, the younger the star cluster is assumed to be.
- Surface gravity can be estimated based on a star's position in the diagram. For example, white dwarfs have an extremely high surface gravity due to their small radii.
However, certain properties like magnetic field strength and the number of planets around a star are not represented in an H-R diagram. These require more specialized observation techniques and data.