Concept explainers
a
To Evaluate: The following prediction. “Type O stars have shorter lives than type G stars”.
b
To Evaluate: The following prediction.
“Type K supergiant stars produce iron before they explode as supernovae.”
c
To Evaluate: The following prediction:
Type F stars become much more luminous near the ends of their lives than they were as main-sequence stars.
d
To Evaluate: The following prediction:
“Type O stars do not become more luminous near the ends of their lives but do become redder.”
e
To Evaluate: The following prediction:
“Type M stars should have longer lives than type K stars.”
f
To Evaluate: The following prediction:
“Stars similar to Sun reach a maximum size of about 100 solar radii during the red giant stage.”
g
To Evaluate: The following prediction:
“Type K main sequence stars will become red giants when their cores run out of hydrogen.”
h
To Evaluate: The following prediction:
“Some stars become white dwarfs at the ends of their lives.”
i
To Evaluate: The following prediction:
“White dwarfs cool with time but do not change much in radius.”
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Chapter 17 Solutions
COSMIC PERSPECTIVE
- Choose the correct statements concerning spectral classes of stars. (Give ALL correct answers, i.e., B, AC, BCD...) A) Neutral hydrogen lines dominate the spectrum for stars with temperatures around 10,000 K because a lot of the hydrogen is in the n=2 level. B) Hydrogen lines are weak in type O-stars because most of it is completely ionized. C) Oh Be A Fine Guy/Girl Kiss Me, is a mnemonic for remembering spectral classes. D) The spectral sequence has recently been expanded to include L, T, and Y classes. E) K-stars are dominated by lines from ionized helium because they are so hot. F) The spectral types of stars arise primarily as a result of differences in temperature.arrow_forwarda) Sketch a generic HR diagram, including labels for the axes. (Take a picture or scan your work and upload it as a separate file.) b) Consider the following three stars, place them on your HR diagram and determine their rough spectral type and class of star. Also calculate their size relative to the Sun. I) L = 0.001 Lsun T = 3000~K II) L = 20,000 Lsun T = 4000K III) L = 0.001 Lsun T = 15,000Karrow_forwardTopic: Life cycle of stars Q. What color are the hottest stars? What color are the coolest stars?arrow_forward
- True or False 8. Almost all stars are in binary systems. The book says: "So far you have been considering the deaths of stars as if they were all single objects that never interact, but more than half of all stars are members of binary star systems."From this, I would not necessarily say that almost all stars are in binary systems based on this alone, but some other information I am finding says up to 85%. However, the numbers seem to be all over the map outside the course material, and I can not find a solid figure in it from what I have looked at. If it helps, Stars and Galaxies, 10th Edition by Seeds and Beckman is my reference material.arrow_forwardChoose the correct statements concerning spectral classes of stars. (Give ALL correct answers, i.e., B, AC, BCD...) A) K-stars are dominated by lines from ionized helium because they are so hot. B) Oh Be A Fine Guy/Girl Kiss Me, is a mnemonic for remembering spectral classes. C) The spectral sequence has recently been expanded to include L, T, and Y classes. D) Hydrogen lines are weak in type O-stars because most of it is completely ionized. E) Neutral hydrogen lines dominate the spectrum for stars with temperatures around 10,000 K because a lot of the hydrogen is in the n=2 level. F) The spectral types of stars arise primarily as a result of differences in chemical composition.arrow_forwardBased on what you learned about stellar evolution, select all of the correct statements from the following list. 1. The period of some Cepheid variables actually changes. 2. When getting dimmer, variable stars are releasing energy; when getting brighter they are storing energy. 3. variable stars are expanding and contracting 4. despite their variability, variable stars stay in a specific position on the H-R diagram. 5. A changing period in a Cepheid variable means that the size of the star is changing and that the star is therefore evolving. 6. Only stars on the instability strip are variable. 7. More massive stars will vary their brightness more quickly.arrow_forward
- White Dwarf Density. If a star the size of the Sun collapses to form a white dwarf the size of Venus, by what factor will its density increase? (Hints: The volume of a sphere is Tp3. The radii of the Sun and Venus are 6.96x105 3 km and 6050 km, respectively.) Please round your answer to two significant digits. Pina! Pinitialarrow_forwardSuppose you were handed two HR diagrams for two different clusters: diagram A has a majority of its stars plotted on the upper left part of the main sequence with the rest of the stars off the main sequence; and diagram B has a majority of its stars plotted on the lower right part of the main sequence with the rest of the stars off the main sequence. Which diagram would be for the older cluster? Why?arrow_forwardThe sketch below shows an H-R diagram for a star cluster. Consider the star to which the arrow points. How is it currently generating energy? Temperature A. by hydrogen shell burning around an inert helium core B. by gravitational contraction C. by core hydrogen fusion D.by core helium fusion combined with hydrogen shell burning E. by both hydrogen and helium shell burning around an inert carbon core Luminosity -→arrow_forward
- Topic: Life Cycle of Stars Q. Describe what would our Sun look like from Earth if it was a massive star? Pls answer in 2-3 sentences. Thank You!arrow_forwardPlease do not give solution in image formate thanku Q: You’ve just discovered another new X-ray binary, which we will call Hyp-X2 (“Hyp” for hypothetical). The system Hyp-X2 contains a bright, G2 main-sequence star orbiting an unseen companion. The separation of the stars is estimated to be 12 million kilometers, and the orbital period of the visible star is 5 days. Use Newton’s version of Kepler’s third law to calculate the sum of the masses of the two stars in the system. a)Express your answer in kilograms to two significant figures. b) Give your answer from the previous part in solar masses. ( Msun= 2.0 x 10 /30 kg). Express your answer as a multiple of sun’s mass to two significant figures. C) Determine the mass of the unseen companion. ( Hint: A G2 main-sequence star has a mass of 1 Msun.) Express your answer as a multiple of sun’s mass to two significant figures. The previous answer was not correct, please help mearrow_forwardMatch each characteristic below of a one-solar-mass star to its appropriate phase. Answer M for Main-sequence Star, or P for Protostar. If the first is M and the rest P, enterMPPPPPP). A) energy generated by nuclear fusion B) pressure and gravity are NOT precisely balanced. C) surface radiates energy at same rate that core generates energy D) radius much larger than the Sun E) energy generated by gravitational contraction F) lasts about 10 billion years G) luminosity much greater than the Sunarrow_forward
- AstronomyPhysicsISBN:9781938168284Author:Andrew Fraknoi; David Morrison; Sidney C. WolffPublisher:OpenStaxFoundations of Astronomy (MindTap Course List)PhysicsISBN:9781337399920Author:Michael A. Seeds, Dana BackmanPublisher:Cengage LearningStars and Galaxies (MindTap Course List)PhysicsISBN:9781337399944Author:Michael A. SeedsPublisher:Cengage Learning
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