Unit 3 Flashcards
Where do sunspots occur
Where strong magnetic activity in the Sun’s outer layers cause relative cooling in small regions
Photosphere
Layer of the sun which emits the most visible light
Chromosphere
Outermost layer of the sun
Corona
Upper region of the chromosphere, where the solar atmosphere becomes much less dense
Granulation
Texturing in the surface on the sun
Convective Zone
A large area where cycles of material flow back and forth from the inner to the outer regions of the zone
Radiative Zone
Zone where energy travels outward. Material gets hotter between the boundary with the convective zone and the core
Nuclear fusion
Physical process which generates energy for the sun. Helps balance out the forces of gravity which would otherwise bring the outer layers crashing into the center
Proton-proton chain
Nuclear reaction series that powers the sun
Luminosity
Absolute power output at the source
Brightness
Apparent output as observed at a distance
Formula: Brightness = luminosity / 4 pi (distance)^2
Star temperature and absorption lines
The cooler a star gets ,the more atoms and molecules can hold on to electrons to create absorption lines
Distance in parsecs
1/parallax angle in arc seconds
High temperature stars are
Smaller and bluer
Lower temperature stars are
Bigger and redder
Increased luminosity doesn’t change the star’s color because
It doesn’t change the temperature, just the amount of light emitted
H-R Diagram
Hertzsprung-Russell Diagram, which shows the relationship between star luminosity and temperature
What influences the luminosity of a star
The amount of energy produced in the core. Less energy= lower luminosity
If the radius of star A is twice that of star B, and both have similar temperatures, how do their luminosities compare?
Star A is 4 times as luminous ad star B
If 2 stars have the same apparent brightness, the fainter one is…
Closer
Apparent Brightness formula
Luminosity/4*pi distance squared
What is the main sequence
The curve on the HR diagram where stars of different masses are located while they’re converting hydrogen to helium in their cores
White dwarf stars
The dying cores of sun-like stars, held up by electron degeneracy pressure
Brown dwarf star
Failed star which failed to start fusion
Medium mass stars end up as
Supernovae and neutron stars
High mass stars end up as
Supernovae and black holes
How do gold and silver end up in stars
Supernovae explosions
Why are things torn apart when they near a black hole?
The part of the object closer to the black hole feels a greater force
the event horizon of a black hole is
The minimum distance from which light can escape
Star’s habitable zone
The region in which liquid water can be present on a planet’s surface
Extremophiles
Life that manages to survive very hostile environments
Radiodurans
Can survive in the high levels of radiation on Mars’s surface
Hydrothermal vent communities
Can exist in the total darkness and pressures in the liquid oceans of Europa d
When was the first extrasolar planet discovered?
1992
The first extrasolar planet in the habitable zone was found in:
2001
Transit Mode
The periodic dimming of light as an exoplanet passes in front of its host star and casts a shadow on Earth’s telescopes. Used to find exoplanets
Open clusters
Clusters not held/bound together well by gravity. Stars within the clusters are flying off in different directions above the escape velocity.
They will disperse in a few million years
Globular star clusters
Concentrated, with lots more stars than open clusters (hundreds of thousands/million stars). Very old and very yellow
Cluster formation tells us about
The age of the cluster
Cat’s Eye nebula
Planetary nebula created when a dying, sun sized star ejects its outer layers of gas into space. Has rings and a symmetrical appearance
Why is the cat’s eye nebula symmetrical
Bipolar jets create matching jets on both sides.
Helix Nebula
The one that looks like a giant eye. red glow caused by hydrogen. Shaped like a donut because of Earth’s line of sight
Nova
Explosion caused by white dwarfs taking on the matter of a nearby companion. Lights up the inside of an otherwise invisible gas cloud
Type I supernova
Created from too much matter being dumped on a white dwarf
