PHYS 104N – Introductory Astronomy
CRNs 34900, 34901, 34902
Summer Session 2022
Homework 5
Due Wednesday, July 20.
Problem 1 (25 points)
What is plotted on a Hertzsprung-Russel diagram? What can we learn from a star’s position in this diagram?
We can learn the luminosity of a star is plotted on a Hertzsprung-Russel diagram. We can learn the classification of a star from its position on this diagram.
Problem 2 (25 points)
Explain why the Sun appears to be stable in size and luminosity.
The sun appears to be stable in size and luminosity because of dynamic equilibrium.
Problem 3 (25 points)
Explain the 11-years Sun spot cycle. What do we observe and why?
The north and south poles of the sun flip every 11 years. The 11 years sun spot cycle observes the sun’s change in its magnetic field. We observe this because it helps us understand and predict the sun’s behavior.
Problem 4 (25 points)
Calculate the mass (or energy) released in one cycle of protons fusing into helium inside the Sun. The mass of protons (hydrogen nuclei) is 1.008 u, the mass of the helium nucleus is 4.0026 u.
4.715 x 10^ -29 kg
