Lab 9 Investigating Stars with the H-R Diagram Summary: The Hertzsprung-Russell (H-R) diagram is one of the most important graphs ever devised in astron- omy. The H-R diagram allows astronomers to investigate the properties of stars and the relationship between spectral class and luminosity. The H-R diagram is particularly useful in studying stars found in clusters since those stars typically formed at the same time. Background: For most of this lab, you will use an online interactive H-R diagram-the Hertzsprung-Russell Dia- gram Explorer-found at this web address: https://astro . unl . edu/mobile/HRdiagram/HRdiagramStable. html This H-R simulator is part of the Nebraska Astronomy Applet Project (NAAP). A screenshot of the simulator is shown below. The user can change the temperature (found on the horizontal axis) and luminosity (found on the vertical axis) of the star and see how its position changes on the H-R diagram Figure 1: H-R Diagram Explorer InterfaceStellar Classifications (14 points total): Stellar Luminosity and Radius (35 points total): 1. Follow these steps to complete the table below. 2. Now let's investigate how a star's luminosity and radius depend on one another while keeping its surface temperature constant. First, navigate to the online interactive H-R diagram: (a) (7 points) Refer to Section 17.3 in our OpenStar Astronomy textbook OR page 30 of the https://astro . unl . edu/mobile/HRdiagram/HRdiagramStable . html Lecture 8 PowerPoint to match stellar colors and surface temperature ranges with their corresponding spectral types. (a) (2 points) Click on one of the green diagonal lines (the lines of constant stellar radius) to place a star marker; upon clicking you should see a colored circle with a green X inside. Be (b) (7 points) Use Wikipedia to research the surface temperatures of the following stars. Use sure to choose a location with T 2 19000 K AND 0.003Ro 10,000 K (b) Colors: red orange yellow yellow-white white blue-white blue (c) Spectral Types: M K G F A B O (d) Luminosities: ~ 1,000Le () Radii: 0.1-1Rg 100R; 100 1,000R; > 1,000Re 7. (5 points) Use your answers from all parts of question 6 to generalize the properties of our closest stellar neighbors. Are they hot or cool? Are they big or small? Are they bright or dim? Are their properties similar to those of our Sun