Universe: Stars And Galaxies
6th Edition
ISBN: 9781319115098
Author: Roger Freedman, Robert Geller, William J. Kaufmann
Publisher: W. H. Freeman
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Chapter 17, Problem 32Q
To determine
The value of B-V color index for very hot and very cold stars.
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"51 Pegasi" is the name of the first normal star (besides the Sun) around which a planet was discovered. It is in the constellation Pegasus the horse. Its parallax is measured to be 0.064 arcsec.
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Chapter 17 Solutions
Universe: Stars And Galaxies
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- Suppose you are given the task of measuring the colors of the brightest stars, listed in Appendix J, through three filters: the first transmits blue light, the second transmits yellow light, and the third transmits red light. If you observe the star Vega, it will appear equally bright through each of the three filters. Which stars will appear brighter through the blue filter than through the red filter? Which stars will appear brighter through the red filter? Which star is likely to have colors most nearly like those of Vega?arrow_forwardDistance from Apparent Brightness (rank; brightest, 8 = dimmest) Name of Star Earth (light years) | 1 = Sun Sirius 8.6 Canopus Arcturus 309 3. 36.7 4 Rigel Vega Alpha Centauri Bernard's Star 773 5 25.3 4.3 7 5.9 8 13 What sentence explains why a star can be much farther from Earth than the Sun, but still be bright? nida nenv A. Distance from Earth and apparent brightness are related. B. Bright stars that are farther away are larger than the Sun. C. The higher it appears in the sky, the brighter the star. D. The apparent brightness scale goes up as stars get dimmer. del sdTarrow_forwardIn the parallax method of determining stellar distances, the angle to a star is measured while the earth is on one side of the sun and then again six months later, as in the diagram below. Assume the earth-sun distance is 1 Astronomical Unit. The parallax angle of Alpha Centauri is 0= 2.1 x 10-4 ° . Find the distance from the sun to a Centauri in light years. Assume a circular orbit for the Earth. a Centauri Earth (June) Earth (December) Sunarrow_forward
- As a star runs out of hydrogen to fuel nuclear fusion in its core, changes within the star usually cause it to leave the main sequence, expanding and cooling as it does so. Would a star with a radius 6 times that of the Sun, but a surface temperature 0.4 times that of the Sun, be more, or less luminous than the Sun? Show and explain your reasoning. You may assume the surface area of a sphere is A = 4πr2.arrow_forwardv Correct Part C Which has a greater luminosity, a star with absolute magnitude -2 or a star with absolute magnitude 8 ? O A star with absolute magnitude 8. A star with absolute magnitude -2. Submit Previous Answers Correct Part D By how much? LM=-2 LM-8 000000001 Submit Previous Answers Request Answer X Incorrect; Try Again; 5 attempts remaining Next > Provide Feedback P Pearson 8:58 PM (cp ツ 4/2/202 earson Education Inc. All rights reserved. | Terms of Use Privacy Policy Permissions Contact Us | 49°F Sunnyarrow_forwardL = ( 0.0813 ) x (Rs) ^2 x 10-0.4m x Ls where L = luminosity of the desired star Rs = distance of the stars in light years m = apparent magnitude of star Ls = Luminosity of Sun = 1.00 The calculated value of Polaris' luminosity is: a. 2382 times Ls b. 6040 times Ls c. 5566 times Ls d. 2612 times Lsarrow_forward
- The a star system contains two stars, one with apparent magnitude m = 10.5 and the other with m = 10.9. What is the combined apparent magnitude of the two stars?arrow_forward15: A star has a parallax angle of 0.0270 arcseconds and an apparent magnitude of 4.641. What is the distance to this star? Answer: 37 16: What is the absolute magnitude of this star? Answer:1.8 17: Is this star more or less luminous than the Sun? Answer "M" for More luminous or "L" for Less luminous. (HINT: the absolute magnitude of the Sun is 4.8) Answer: M 18: What is the luminosity of this star? (HINT: The luminosity of the Sun is 3.85×1026 W.) Please answer question #18, #15-17 are correct, the photos provide the work for them.arrow_forwardThe Hα spectral line has a rest wavelength of 6562.8 ˚A (remember: 1 ˚A = 10−10 m). In star A, the lineis seen at 6568.4 ˚A, in star B it’s seen at 6560.3 ˚A, and in star C it’s seen at 6562.8 ˚A. Which star ismoving the fastest (along the line of sight) and what is the radial velocity of each star?arrow_forward
- = A star population is composed of stars with masses in the range between 1M and 150M. The initial mass function is = 0 (M/M)-2.3, where o (Mo). The luminosity of a star = (M/M) 3.3. Calculate the percentage of the total luminosity of the stars in the population which is produced by stars with mass between 120M and 150M. scales with its mass as L/Larrow_forwardThe spectrum of a typical star shows absorption lines at different wavelengths than their laboratory values. If the observed wavelength is less than its laboratory value of 656.3 nm, one can conclude that... A. The separation between Earth and the star is decreasing. B. The separation between Earth and the star is increasing. C. The separation between Earth and the star is unchanging D. No conclusion is possible.arrow_forwardA brand new telescope has been named after you. It is therefore only fitting that you get to make the very first set of observations. During your first night observing, you first measure the apparent brightness and spectrum of a group of stars that appear close to each other within the telescopes field of view. From a separate set of observations 6 months later, you are able to measure each star’s parallax. Next you plot the luminosity and temperature of each star in a Hertzsprung-Russell Diagram What features below help you conclude that the group of stars is a star cluster? Explain Approximately how old do you think this star cluster is? Explain How do you expect the spectrum of the most luminous and least luminous main sequence stars in the cluster to differ? Explain why these differences occur in terms of the star’s properties and any measured absorption lines. A year after your discovery, another new star cluster has been found by the same telescope, but its distance is too far…arrow_forward
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