LECTURE 13

What is a binary star?

• A star that is orbited by another star

• A star that emits binary code

• A star that has a binary system

• A star that has a planet orbiting around it

How can we measure the mass of a star?

• By observing its brightness

• By measuring its temperature

• By studying its orbit around another star

• By analyzing its composition

What is a Hertzsprung-Russell (H-R) Diagram?

• A visual representation of the interstellar medium

• A graph that shows the luminosity of stars as a function of their temperature

• A diagram that represents the life cycle of a star

• A chart that classifies stars based on their spectral type

What is the main sequence phase for stars?

• The phase when stars are forming

• The phase when stars are burning hydrogen

• The phase when stars are burning helium

• The phase when stars are dying

Which type of stars live longer, small stars or big stars?

• They have the same lifespan

• Small stars

• It depends on their composition

• Big stars

What are the two types of star clusters?

• Open clusters and globular clusters

• Young clusters and old clusters

• Bright clusters and dim clusters

• Northern clusters and southern clusters

What are the letters used for spectral type?

• OBAFGKM

• RGBYVIO

• ABCDE

• XYZW

What is the interstellar medium?

• The gas between the stars

• The region where stars are formed

• The dark matter in the universe

• The space between galaxies

What are the different phases of the interstellar medium?

• HII regions, HI regions, and molecular clouds

• Hot gas, cool gas, and dense gas

• All of the above

• Ionized gas, neutral gas, and molecular gas

How do we measure the composition of molecular clouds?

• By mapping them at radio wavelengths

• By mapping them at UV or blue wavelengths

• By observing starlight behind the clouds

• By analyzing their dust particles