# 2021-01-24

astr-1102

• Chapter 18
• 18.1: A Stellar Census
• Learning Objectives
• Explain why the stars visible to the unaided eye are not typical
• Describe the distribution of stellar masses found close to the Sun
• A stellar census is hard because
• We may not count all inhabitants
• Our local neighbourhood may not include all possible types of stars
• 18.2: Measuring Stellar Masses
• Learning Objectives
• Distinguish the different types of binary star systems
• Understand how we can apply Isaac Newton's version of Johannes Kepler's third law to derive the sum of star masses in a binary star system
• Apply the relationship between stellar mass and stellar luminosity to determine the physical characteristics of a star
• 18.3: Diameters of Stars
• Learning Objectives
• Describe the methods used to determine star diameters
• Identify the parts of an eclipsing binary star light curve that correspond to the diameters of the individual components
• 18.4: The H-R Diagram
• Learning Objectives
• Identify the physical characteristics of stars that are used to create an H-R diagram
• Describe how those characteristics vary among groups of stars
• Discuss the physical properties of most stars found at different locations on the H-R diagram
• Such as radius, mass, etc.