Assignment 3 Intro to Astronomy

.

Introduction to Astronomy

Written Assignment 3

1. Explain how the Hertzsprung-Russell diagram is constructed of the four main groupings of stars. Identify characteristics of the four main groupings of stars on the diagram.

In Chapter 8 of the textbook, The Hertzsprung-Russell diagram is described

as a graph that separates the effects of temperature and surface area on stellar luminosities and enables astronomers to sort stars according to their diameter. The diagram has the luminosity on the vertical axis and temperature on the horizontal axis. Some versions on the diagram may also have the Spectral type listed at the top of the chart as well. Stars are represented on the diagram by a dot that represents their luminosity and temperature.

Now that we know what the diagram is we can start talking about how it is used and how stars are placed on it. The location on the diagram tells us a great about the star. If the star is towards the top of the diagram then we know the star’s luminosity is very high, by contrast we also know that if the star is near the bottom the luminosity is very low. While points that are close to he left edge are very hot and stars near the right edge are very cool. This allows us to compare and contrast a star’s temperature with its temperature with it luminosity. Once you have plotted the stars you would come to see that 90% of the stars fall within the normal ratio or main sequence, while a few fall outside of the normal and are named white dwarfs, giants and super giants. Keep in mind that where a star appears on the diagram has nothing to do with where it is located in space.

You can use this type of diagram to also plot cars, instead of using luminosity and temperature; you would use horsepower and weight. If you were to do this you would see that the heavy high-powered cars would be in the upper left corner while light, low-powered cars would be at the lower right. You would also...