NATS 1740 Lecture Notes - Lecture 5: Apparent Magnitude, Minute And Second Of Arc, Binary Star

• School: York University
• Department: Natural Science
• Course: NATS 1740
• Professor: Alireza Rafiee

Document Summary

Nats 1740a lecture #6 12. 1 properties of stars. The same amount of starlight passes through each sphere. The surface area depends on the square of its radius (distance from the star) so the amount of light passing through each unit of area depends on the inverse square of distance from the star. Brightness of a star depends on both distance and luminosity. It is passing through each sphere is the same. Amount of power a star radiates (energy per second = watts) You divide luminosity by the area to get brightness. Amount of starlight that reaches earth (energy per second per square metre) The relationship between apparent brightness and luminosity depends on distance: We can determine a star"s luminosity if we can measure its distance and apparent brightness: It is the apparent shift in the position of a nearby object against a background of more distant objects.