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Blue-white stars are typically ______ in temperature, while orange-red stars are typically ______ in temperature.
Hot; cool
What two elements make up most of the Sun?
Hydrogen and helium
What unit do scientists use to describe distances between planets and their star? Write the full name and abbreviation.
Astronomical unit (AU)
A planet has a density of 5.5 g/cm³. Is it more likely terrestrial or a gas giant?
Terrestrial planet
Planet J is close to its star, while Planet K is far from its star. Based on the thermal energy each planet receives, infer the most likely phase of water on each planet’s surface.
Planet J: gas (water vapor); Planet K: solid (ice).
What is the name of the explosive event that can mark the end of a massive star’s life?
Supernova
As planets get closer to the Sun, how does their orbital period change?
Decreases / becomes shorter
Which planet has the most circular orbit: A (0.02), B (0.09), C (0.40), or D (0.95)?
Planet A
Which planet has the most elliptical orbit: A (0.03), B (0.12), C (0.35), or D (0.65)?
Planet D
What region around a star receives the right amount of energy for liquid water to potentially exist on a planet’s surface?
Habitable zone
Which star has the shortest lifespan: W (0.5 solar masses), X (1 solar mass), Y (5 solar masses), or Z (15 solar masses)?
Star Z
Scientists can determine a star’s composition by comparing the ________ ________ of the star and the elements and looking for matching patterns.
Spectral Lines
Which law states that planets orbit in ellipses?
Kepler's First Law
Planet A orbits the Sun at an average distance of 0.4 AU, Planet B at 1 AU, and Planet C at 3 AU. Which planet has the greatest orbital speed?
Planet A
True or False: A planet moves faster in its orbit when it is closer to its star and slower when it is farther away.
True (Kepler's Second Law)
The Cosmic Tug of War: What two opposing effects help maintain a stable main-sequence star? You must state the directions.
Gravity (inward); nuclear fusion pressure (outward)
What is the last element a massive star can produce through fusion before fusion no longer releases energy?
Iron (Fe)
Using the equation e=f÷d scientists can calculate a planet’s orbital eccentricity. What do the variables f and d represent? Hint: Think back to Lab 6.
f = distance between the two foci
d = length of the major axis
Scientists observe a star becoming slightly dimmer when a planet passes in front of it. What method are they using to detect the planet?
Transmit method
During a planetary transit, what can the depth of a star’s brightness dip help scientists estimate?
Planet size / radius
Draw the axes of a graph used to show a planetary transit. Label the x-axis and y-axis with the correct variables.
x-axis (Horizontal): Time
y-axis (Vertical): Star brightness
Stars are categorized into four main groups based on their placement and physical properties on the Hertzsprung-Russell (H-R) diagram. What are the four groups?
Main sequence, white dwarfs, giants, and supergiants
Using the equation R = 3√(MxT2) , scientists can calculate a planet’s average distance from its host star. What do the variables M and T represent?
M = mass of the host star (solar masses)
T = period of revolution (Earth years)
What law relates a planet’s orbital period to its average orbital distance?
Kepler’s Third Law
During a planetary transit, what does the time between repeated brightness dips help scientists determine?
Orbital period