PSU ASTRO 7N CORE MANUAL UPDATED EXAM
QUESTIONS AND ANSWERS GRADED A+
✔✔Brightness - ✔✔Apparent output of something observed at a certain distance
✔✔Inverse-Square Law - ✔✔B=L/(4pi(d^2))
✔✔4 - ✔✔If star A is (X) times as luminous as star B, then stars A and B would appear
equally bright if star A were 2 times as far away as star B
✔✔Parallax Method - ✔✔D=1/p
D= Distance in parsecs
p= Parallax angle in arc seconds (1/3600)
✔✔Red - ✔✔What color are cooler stars?
✔✔Blue - ✔✔What color are hotter stars?
✔✔OBAFGKM - ✔✔The temperature sequence (from hot to cold) of spectral classes
✔✔Alpha Centauri - ✔✔The closest star to our solar system other than the sun
4.3 light years away
✔✔Sirius (Dog Star) - ✔✔Brightest star in the sky
✔✔Red Dwarfs - ✔✔Which stars are located on the lower right of the HR Diagram?
Cool, faint, small
✔✔Blue Giants - ✔✔Which stars are located on the upper left of the HR Diagram?
Hot, bright, large
✔✔Red Giants/Supergiants - ✔✔Not on the main sequence
Burning helium and other elements in their cores (not hydrogen)
Starting to die
Large and very luminous
Cooler
Top right of HR DIagram
✔✔Stellar nursery, protostar, main sequence, red giant, planetary nebula, white dwarf -
✔✔Sun's History
✔✔Planetary Nebula - ✔✔Ejected envelope (the layers of the core) of a low to
intermediate mass star
, ✔✔White Dwarf - ✔✔End state of a star's core
About the size of the Earth
✔✔Brown Dwarfs - ✔✔Failed stars
Don't heat up enough to have nuclear reactions in their core
✔✔Onion Skin Model - ✔✔When a massive star burns through hydrogen and then
helium and then more massive elements it leaves behind layers
Concentric shells of fusion zones involving different chemicals
✔✔Iron - ✔✔Stable element that stops the burning of a star
✔✔Type II Supernova - ✔✔Violent explosion with the star's core left behind
Creates an environment for the fusion of elements heavier than iron to form
✔✔Event Horizon - ✔✔Spherical boundary around a black hole where nothing can
escape
Escape velocity of this area is faster than the speed of light
✔✔Singularity - ✔✔A point of infinite density
✔✔Drake Equation - ✔✔Method to estimate the number (N) of
communicating/technological civilizations in our Galaxy
✔✔N - ✔✔The number of intelligent and communicating civilizations in the Milky Way
Galaxy
✔✔R* - ✔✔The rate of formation of habitable stars in the galaxy
✔✔Fp - ✔✔Fraction of stars in R* that have planetary systems
✔✔Ne - ✔✔The average number of Earth-like planets in the Fp systems
✔✔Fl - ✔✔Fraction of planets from Ne in which life develops
✔✔Fi - ✔✔Fraction of plants with life that eventually gives rise to intelligent life
✔✔Fc - ✔✔Fraction of intelligent species that are capable of interstellar communication
✔✔L - ✔✔Average lifetime of communicating civilizations
✔✔Kepler's 3rd Law - ✔✔P2=a3
✔✔Low Mass Stars - ✔✔Stars born with less than about 2 solar masses of material
QUESTIONS AND ANSWERS GRADED A+
✔✔Brightness - ✔✔Apparent output of something observed at a certain distance
✔✔Inverse-Square Law - ✔✔B=L/(4pi(d^2))
✔✔4 - ✔✔If star A is (X) times as luminous as star B, then stars A and B would appear
equally bright if star A were 2 times as far away as star B
✔✔Parallax Method - ✔✔D=1/p
D= Distance in parsecs
p= Parallax angle in arc seconds (1/3600)
✔✔Red - ✔✔What color are cooler stars?
✔✔Blue - ✔✔What color are hotter stars?
✔✔OBAFGKM - ✔✔The temperature sequence (from hot to cold) of spectral classes
✔✔Alpha Centauri - ✔✔The closest star to our solar system other than the sun
4.3 light years away
✔✔Sirius (Dog Star) - ✔✔Brightest star in the sky
✔✔Red Dwarfs - ✔✔Which stars are located on the lower right of the HR Diagram?
Cool, faint, small
✔✔Blue Giants - ✔✔Which stars are located on the upper left of the HR Diagram?
Hot, bright, large
✔✔Red Giants/Supergiants - ✔✔Not on the main sequence
Burning helium and other elements in their cores (not hydrogen)
Starting to die
Large and very luminous
Cooler
Top right of HR DIagram
✔✔Stellar nursery, protostar, main sequence, red giant, planetary nebula, white dwarf -
✔✔Sun's History
✔✔Planetary Nebula - ✔✔Ejected envelope (the layers of the core) of a low to
intermediate mass star
, ✔✔White Dwarf - ✔✔End state of a star's core
About the size of the Earth
✔✔Brown Dwarfs - ✔✔Failed stars
Don't heat up enough to have nuclear reactions in their core
✔✔Onion Skin Model - ✔✔When a massive star burns through hydrogen and then
helium and then more massive elements it leaves behind layers
Concentric shells of fusion zones involving different chemicals
✔✔Iron - ✔✔Stable element that stops the burning of a star
✔✔Type II Supernova - ✔✔Violent explosion with the star's core left behind
Creates an environment for the fusion of elements heavier than iron to form
✔✔Event Horizon - ✔✔Spherical boundary around a black hole where nothing can
escape
Escape velocity of this area is faster than the speed of light
✔✔Singularity - ✔✔A point of infinite density
✔✔Drake Equation - ✔✔Method to estimate the number (N) of
communicating/technological civilizations in our Galaxy
✔✔N - ✔✔The number of intelligent and communicating civilizations in the Milky Way
Galaxy
✔✔R* - ✔✔The rate of formation of habitable stars in the galaxy
✔✔Fp - ✔✔Fraction of stars in R* that have planetary systems
✔✔Ne - ✔✔The average number of Earth-like planets in the Fp systems
✔✔Fl - ✔✔Fraction of planets from Ne in which life develops
✔✔Fi - ✔✔Fraction of plants with life that eventually gives rise to intelligent life
✔✔Fc - ✔✔Fraction of intelligent species that are capable of interstellar communication
✔✔L - ✔✔Average lifetime of communicating civilizations
✔✔Kepler's 3rd Law - ✔✔P2=a3
✔✔Low Mass Stars - ✔✔Stars born with less than about 2 solar masses of material
