HR diagram-lab online-1.docx

NAME______________________ CLASS_________ Instructions: Go to web site http://astro.unl.edu . Click on the Nebraska astronomy ap- plet project and then go to NAAP Modules(at top of screen) and pick HR Diagram. Read the materials and complete the guide below and complete the exer- cises and complete the document below—the background materials will help you answer the questions—the flash demonstration will help you com- plete the rest. ON LINE LAB 10 Nebraska Astronomy Applet Project Student Guide to the HR DIAGRAM _____________________________ NAAP – HR Diagram Explorer 1/10

HR Diagram – Student Guide Pretest Score: Background Information Work through the background sections on Spectral Classification, Luminosity, and the Hertzsprung-Russell Diagram. Then complete the following questions related to the background information. Star Surface Tempera- ture K Spectral Type Color Betelguese 3,530 M2 Orange Arcturus 4,300 K5 Yellow The sun 5,830 G2 Yellow Procyon A 6,530 F5 Yellow-White Sirius A 9,145 A1 White Rigel A 11,000 B9 White-Blue Delta Orionis 33,200 O9 Blue 1.The table below summarizes the relationship between spectral type, temperature, and color for stars. Note that the surface temperature of the stars in the table increases. NAAP – HR Diagram Explorer 2/10

2.Complete the following table related to stellar luminosities in solar units using the equation . Radius (R ⊙ ) Temperature (T ⊙ ) Luminosity (L ⊙ ) 1 1 1 1 2 16.8 3.02 1 9 1 1/2 0.057 3.The mass luminosity relation describes the mathematical relationship between lumi- nosity and mass for main sequence stars. It describes how a star with a luminosity of 2 M ⊙ would have a luminosity of 11.31 L ⊙ while a star with luminosity of 3,160 L ⊙ would have an approximate mass of 10 M ⊙. HR Diagram Explorer Open the HR Diagram Explorer . Begin by familiarizing yourself with the capabilities of the Hertzsprung-Russell Diagram Explorer through experimentation. · An actual HR Diagram is provided in the upper right panel with an active location indi- cated by a red x. This active location can be dragged around the diagram. The options panel allows you control the variables plotted on the x-axis: (temperature, B-V, or spec- tral type) and those plotted on the y-axis (luminosity or absolute magnitude). One can also show the main sequence, luminosity classes, isoradius lines, or the instability strip. The Plotted Stars panel allows you to add various groups of stars to the diagram. · The Cursor Properties panel has sliders for the temperature and luminosity of the active location on the HR Diagram. These can control the values of the active location or move NAAP – HR Diagram Explorer 3/10

in response to the active location begin dragged. The temperature and luminosity (in solar units) are used to solve for the radius of a star at the active location. · The Size Comparison panel in the upper left illustrates the star corresponding to the ac- tive location on the HR Diagram. Note that the size of the sun remains constant. NAAP – HR Diagram Explorer 4/10

Your preview ends here

Eager to read complete document? Join bartleby learn and gain access to the full version

Access to all documents
Unlimited textbook solutions
24/7 expert homework help