Astronomy 122 Distance Education Second Homework Assignment

The Hipparcos satellite was a parallax mission designed to greatly increase the numbers of stars with parallax measurements. Find out when this mission was flown, how many stars were measured, what the distance limit of the Hipparcos sample is compared to the ground based sample and whether or not there are any substantial changes to our view of the HR diagram as a result of these measurements. (Note we will be getting to this material later in the course).
For main sequence stars, there is a relationship between their total mass and their energy output (which we call the luminosity). Report on the form of this relationship and how it was empirically discovered.
Astronomers have recently discovered a new spectral type for stars. hey are classified as Spectral type L. When were these stars discovered, ow were they discovered and what kind of stars do they appear to be?

These 4 questions are designed to test your knowledge of applying the inverse square law. (Play with the simulator that can be found at the bottom of the page in Lecture E, Module 1).
The following shows the properties of 4 stars. Luminosity refers to the intrinsic energy output of the star and all luminosity values refer to the luminosity of Star A which is 1 Unit.
Star A is at a distance of 10 light years and deposits a flux of 100 units on our 1 square centimeter detector.
Believe it or not, this is all the information needed to answer the questions. All of the units are relative to Star A so you simply scale from what you know for Star A to determine either the flux, luminosity or distance of the other Stars.
- Star B: Luminosity = 1 Distance = 100
- Star C: Luminosity = 4 Distance = 40
- Star D: Flux = 200 Distance = 10
- Star E: Luminosity = 1 Flux = 25
Show all work or reasoning in answering the following questions.
What is the flux on the detector for Star B?
What is the flux on the detector for Star C?
What is the luminosity of star D?
What is the distance of Star E?