Eccentricity
What is the formula used to calculate the eccentricity of an orbit?
Eccentricity = Distance between foci ÷ Length of major axis
What two properties are compared on the H–R Diagram?
Luminosity and Temperature
Which force keeps planets in orbit around the Sun?
Gravity
Which planet is closest to the Sun?
Mercury
What element fuels a main sequence star?
Hydrogen
What is the eccentricity of a perfectly circular orbit? (0-1)
0
According to the H–R Diagram, what is the surface temperature of the Sun?
About 5,800 K
Which law describes the relationship between a planet’s orbital period and distance from the Sun?
Kepler’s Third Law
Which two planets are considered “gas giants”?
Jupiter and Saturn
What is the next stage in a Sun-like star’s life after the main sequence?
Red giant
If an ellipse has foci 4 cm apart and a major axis of 10 cm, what is its eccentricity?
0.4
What type of star is hotter and brighter than the Sun?
Blue giants or supergiants
What happens to a planet’s orbital velocity as it gets closer to the Sun?
It increases
Which planet has the longest period of revolution?
Neptune
What process releases energy inside stars?
Nuclear fusion
Which planet in our solar system has the most eccentric orbit according to the reference tables?
Mercury
On the H–R Diagram, where are white dwarfs located?
Bottom left corner
Why do planets move faster when closer to the Sun?
The Sun’s gravitational pull is stronger at a shorter distance.
How does the density of the inner planets compare to the outer planets?
Inner planets are denser and rocky; outer are less dense and gaseous.
What stellar remnant forms after a supernova explosion?
Neutron star or black hole
Describe how increasing eccentricity affects the shape of an orbit.
The orbit becomes more elongated or oval-shaped.
Explain how mass affects a star’s life cycle.
Higher mass stars have shorter lifespans and end as supernovae or black holes.
What shape are all planetary orbits?
Elliptical
Which planet’s atmosphere contains the most carbon dioxide?
Venus
Explain why massive stars have shorter lifespans than smaller stars.
They burn fuel much faster due to higher core temperatures and pressure.