AST 102: Lecture Exam 1 Review This review sheet serves as a reminder of the material covered in the lectures. It should be noted that some items from lecture may not be included on this review sheet, but will still be referenced on the exam. As such, use these questions as a reminder of the material that was covered in the lectures while studying from the textbook and the notes you took during lectures. Questions for the exam will focus on classroom lecture/discussion, which may include additional material not found within this review sheet. Students have a copy of the recommended textbook (ASTRO, by Backman & Seeds) should also read the relevant chapers and sections (Chapters 1, 4.1, 5.1, 5.2, and 6). Be sure that you understand how to use your scientific calculator properly. Be able to write numbers in scientific notation and read/interpret numbers presented in scientific notation. It may be helpful to review how to use scientific notation as a way of making calculations in case you do not have a proper calculator. Do you understand why astronomers use units such as the astronomical unit (AU) and the light-year (L.Y.)? How are the astronomical unit and light-year defined? What are the goals of science, in general, and astronomy, in particular? Do you understand how the scientific method works? What the major limitations astronomers face in studying celestial objects? Can you provide any examples of such limitations? Do you have a good understanding of the following terms? Rotation vs. Revolution Facts, Laws, Theories, Models What properties define an object as a planet? How do Pluto, the Moon and an asteroid fall short of that definition? What characteristic(s) separate a star from a planet? What are the basic properties of the following astronomical objects? Stars Planets Moons (Satellites) Exoplanets Star Clusters Galaxies the Universe Properties of Light and Matter Can you describe the structure of an atom? Do you know what makes one element different from another? What is an isotope? What is a molecule? Do you understand how the concept of temperature is related to the motion of atoms/molecules? Do you understand how changing the temperature of a substance will change the excitation state (ground, excited, ionized) of atoms as well as the state of matter? Can you define the wave properties of light (wavelength, frequency, speed of light)? Do you understand how light can be described as a particle (photon)? Can you make the following calculations if you are given the equations? - energy of an individual photon - luminosity of a star - the wavelength of light that is emitted by a star in the greatest amount (λpeak) Do you know the basic principles of the reflection and refraction of light? Do you know how to compare the different parts of the EM spectrum with regards to wavelength, frequency, and energy? Do you know how light and matter interacts to form an absorption spectrum? Star Properties Are you familiar with how astronomers use solar units as a way of describing physical qualities of other stars? Do you know the surface temperature, total lifespan, and general composition of the Sun? How is the process of stellar parallax used to determine the distance to a star? Do you understand how the brightness of a star depends on the star’s luminosity and the distance an observer is away from the star? Are you familiar with how the magnitude system is used to rank stars according to brightness (apparent magnitude) and luminosity (absolute magnitude)? Can you use the magnitude system to obtain the relative distances to stars? Do you know how the order of spectral classes is arranged? Can you tell a star’s relative temperature, color, and luminosity based on its designated spectral classification? How is the Doppler Effect used to determine how fast a star is traveling in space? How is it possible to tell whether a star is moving in a direction toward or away from the Earth? Star Properties Practice Examples Equations Luminosity Equation: L = 4 R 2 T4 , where 5.67 x 10 -8 Wein’s Law: peak = 3.00 x 10 6 T 1. The properties for the star, Arcturus, and the star, Spica, are listed in the table below. Complete the chart by calculating the luminosity and peak wavelength for each star,and provide the color that each star will appear to be. Star Size (m) Surface Temp (K) Arcturus Spica 1.80 x 1010 5.43 x 109 4300 20,000 Luminosity peak Color Of the two properties, size and temperature, which one has a greater influence on how luminous a star will be? 2. Use the information in the table below to answer the following questions. Star Spectral Type Betelgeuse Procyon Castor M2 I F5 V A1 V Color Apparent Mag (m) Absolute Mag (M) 0.58 0.34 -5.14 Rel. Distance 1.33 -2.31 0.63 a. Determine the color of each of the stars and write your response in the appropriate column. b. Use the information provided in the table to fill in all the remaining blank cells. c. Which star is hottest? Coolest? d. Which star is largest? Smallest? e. Which star appears the brightest? The faintest? f. Which star is the most luminous? The least luminous? g. Which star is closest to the Solar System? Furthest from the Solar System?