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AST-101-OL0102018DECWritten Assignment 3Question 1:The Hertzsprung-Russell diagram is a useful tool for astronomers to plot and understandthe correlation of temperature, luminosity and size of stars.The plotting of the stars within thediagram can identify characteristics such as stable hydrogen burning or if it has used itshydrogen and is moving to a new phase in the lifecycle of the star. (“H-R Diagram,” n.d.)Understanding the layout of the diagram is critical to understanding how the informationis utilized.The diagram is laid out along 2 axis which are able to identify both luminosity andtemperature.Luminosity, represented by solar unit’s L/L☉, identifies the amount of light that thestar produces and is set on the vertical of the diagram.This means brighter stars are found atthe top of the diagram while less bright stars are found at the bottom.The horizontal axis isrepresented by temperature identified by kelvin.The hotter stars are found to the left of thediagram while cooler stars are found on the right.For an extra measure of identificationspectral type is listed on the top of the diagram, allowing for easy identification of spectral type.(Seeds & Backman, 2014)Within the diagram there are the 4 main groupings of stars that can easily identified.Supergiant’s are the first groupings of stars.These stars are large high luminosity stars that arefound at the top of the HP diagram.Giant stars have less luminosity than supergiant’s and arefound in the center right because the they burn cooler.Dwarf stars are found across the bottomof the diagram as they are low luminosity.The largest grouping of stars is the main sequence.This is the group of stars that falls within a diagonal from the top left to the bottom right cornerof the diagram.At the top left is the hotter brighter stars and it works down to the coolerdimmer stars.