AS101 Assignment #9W Questions and Answers 100% Pass

AS101 Assignment #9W Questions and Answers 100% Pass What do you call the region of the HR diagram that represents giant stars that are fusing helium in their cores and then in their shells? - horizontal branch Why are star clusters important to our study of stars? - because they allow us to test our theories and models of stellar evolution What property is the same for all stars in a star cluster? - age Which point indicates the location on the H-R diagram of a one-star-mass star when it stars to fuse helium? - 3 Why can't the lowest-mass stars become giants? - Their centers never get hot enough How is a giant star different from the star it evolved from? - A giant is cooler and more luminous After they leave the main sequence, what happens to stars with masses between 0.4 and 4 solar masses? - They undergo thermonuclear fusion of hydrogen and helium, but never get hot enough to ignite carbon 2 | P a g e Author: Katelyn Whitman. ©2025, All Rights Reserved. About how long will a 0.5 solar mass star spend on the main sequence? - 57 billion years For a star with a mass similar to that of the Sun, what is the last stage of the nuclear fusion? - helium to carbon and oxygen A low mass star goes through several stages of life from birth to death. Which of the following lists are in correct order? - protostar, main sequence star, red giant, planetary nebula, white dwarf What happens to stars that have ejected a planetary nebula? - They become a white dwarf After what evolutionary stage does a star become a white dwarf? - giant What does a planetary nebula do? - the expelled outer envelope of a medium mass star What does a planetary nebula do? - produces an emission spectrum What is the term for a collection of 100 to 1000 young stars in a region about 80 light- years in diameter? - open cluster What is the term for a collection of 105 to 106 old stars in region 30 to 100 light-years in diameter? - globular cluster What is the defining characteristic of stars within a cluster that at the turnoff point? - They are just leaving the main sequence 3 | P a g e Author: Katelyn Whitman. ©2025, All Rights Reserved. What is the approximate age of the star cluster in the H-R diagram? (Hint: Main sequence stars of spectral types O and B have a core supply of hydrogen that is sufficient to the last about 250 million years; types A and F, about 2 billion years; type G about 10 billion years; types K and M about 30 billion years. The apparent magnitude scale means that larger numbers are toward the bottom of the vertical axis.) - 10 billion years Refer to the H-R diagram. What type of star do the two data points above spectral type "A" represent? - white dwarfs with mass less than the sun's mass Refer to the H-R diagram. What type of star do the data points above spectral type "M" represent? - main sequence stars with mass less than the sun's mass Refer to the H-R diagram. How would the H-R diagram of an older star cluster look different? - The lower main sequence would look the same, but the turnoff would be at spectral type K or M Refer to the H-R diagram. How would the H-R diagram