Ch 11 - Chapter 11 Review Questions 1. (c) The parallaxes...

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Chapter 11 Review Questions 1. (c) The parallaxes and corresponding distances of over a million of nearby stars have been determined with varying degrees of precision. 2. (a) absolute magnitude 3. (d) mass 4. (e) −1.5. Remember that the scales for apparent and absolute magnitude run “backward” in the sense that the larger, positive numbers indicate dimmer stars, while the larger negative numbers indicate brighter stars. 5. (b) A0 6. The view of a relatively nearby object against a more distant background is slightly different in each eye allowing the brain to judge distance. The view of a relatively nearby star against the background of more distant stars is slightly different from one side of the Earth’s orbit compared to the other side. This allows astronomers to calculate the distance. 7. Stellar parallax is the apparent annual displacement of a comparatively nearby star relative to more distant stars caused by a change in the position of the observer as a result of the Earth’s revolution around the Sun. 8. Astronomers measure the apparent angular movement of a star in the sky, ideally over a period of six months so that we view the star from opposite sides of the Sun. These measurements are used to create a right triangle with the Earth, that star, and the Sun at the three vertices. Knowing that the distance from the Earth to Sun is 1 AU, trigonometry allows us to calculate the distance of the star from Earth. 9. As the distance increases, the parallax decreases until it is too small to measure. So parallax works only for nearby stars. 10. Apparent magnitude refers to how bright a star looks from the Earth regardless of the star’s distance from us. Absolute magnitude is how bright the star would appear if its distance was standardized as 10 pc from Earth. By eliminating the effect of different distances between stars and the Earth, astronomers are able to study their other properties, such as size and temperature. 11. You would observe the star’s apparent magnitude and determine its distance using, for example, the
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Ch 11 - Chapter 11 Review Questions 1. (c) The parallaxes...

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