Exam 3 Flashcards
What are Sunspots?
Cool areas on the sun’s surface with strong magnetic fields
How do scientists study the interior of the Sun?
Mathematic Models
Why does the Sun shine?
Nuclear Fusion
Gravitational Equilibrium
The balance between gravity and pressure
Energy Balance
The balance between incoming and outgoing energy
What is Solar Weather?
Space Weather that’s caused by activity on the Sun’s surface
The Sun’s mass compared to Earth’s mass
300,000 times more massive
What is the hydrogen core fusion temperature inside our Sun
About 27 million degrees F or 15 million degrees C
How many years does it take a solar cycle to transition from maximum to minimum
11 years
How does strong solar activity affect out lives on Earth
Auroras, Interference with radio communications, disable earth-rotating satellites
What is the HR Diagram?
A graphical tool used to classify stars based on their luminosity, spectral type, color, temperature, and evolutionary stage
How do we learn the mass of stars?
their orbital period and average distance.
How does color relate to a stars surface temp?
Different colors mean different thermal radiation. (ROYGBIV) Color allows astronomers to calculate surface temp
How long will our sun be on the main sequence?
10 billion years
What is spectral classification?
Sorting stars based on their colors
What does it mean to be on the main sequence?
A star is in its stable, adult phase where it fuses hydrogen into helium to produce energy
Once off the main sequence, how do stars produce energy?
Through nuclear fusion
What are giants/supergiants?
Stars that have exhausted their central core supplies of hydrogen for fusion
What are White Dwarfs?
The exposed core of dead stars
How does the HR diagram show the surface temp of stars?
HR diagram shows hottest stars at the top and coolest stars at the bottom
How long does a star spend on the main sequence?
Most of its life (10 billion years)
How does the parallax angle help us learn about stars?
By measuring snapshots taken at different times and measuring the shift in angle to the star
What does “oh be a fine guy, kiss me” represent?
The spectral types of stars (O hottest, M coolest)
What is the most fundamental property of a star?
It’s ability to generate light and heat through nuclear fusion
Which has a higher temp, Blue or Red star?
Blue Star
final element in high mass stars
Iron
Why does a star leave the main sequence?
Because the star runs out of fuel
What are 3 significant stages the sun will pass through once it leaves the main sequence?
Red giant, planetary nebula, and white dwarf
Which have shorter life cycles? Low or High Mass Stars? Why?
High Mass Stars, they burn through their fuel faster
What are the likely end states of high mass stars?
Exploding in a supernova or collapsing in a black hole
What important role do supernovas play in the galactic recycling?
By scattering heavy elements into space which then form stars and planets
Why is the sun incapable of fusing elements heavier than HE?
There is not enough temperature or pressure
How long does it take photon energy from the suns core to reach the suns surface?
100,000 years
What is a Brown Dwarf?
An object with a mass less than 8% of the sun, which cannot have enough nuclear reactions in its core to be a star.
What is a neutron star?
A ball of neutrons left over from a massive star supernova and supported by neutron degeneracy pressure
What would happen to a White Dwarf in a closed binary system if it gains enough mass from its companion star to exceed 1.4 Solar masses?
It would explode in a supernova
What is a White Dwarf?
The remains of a star that ran out of fuel for nuclear fusion
What is degeneracy pressure?
A pressure exerted by dense material
Life cycles of low mass stars
Protostar, main sequence star, red giant, white dwarf
Life cycles of high mass stars
Main sequence star, supernova, glowing ember
Mass limit for a white dwarf
1.4 solar masses
Which is bigger, low or high mass white dwarf
Low Mass White Dwarf
Mass limit of a neutron star
2.16
Pulsars
Spinning neutron stars that beam radiation
Are Neutron stars smaller or larger than white dwarfs?
Smaller
Event Horizon
Spherical surface of a black hole
Schwarzschild Radius
the distance from the center of a black hole to its event horizon
What can escape from the Event Horizon of a Black Hole
Nothing
What causes gamma ray bursts
when massive stars explode or when two neutron stars collide
What happens when black holes merge
Burst of gravitational waves
Gravitational Waves
ripples in the fabric of spacetime caused by massive objects moving
What is a Nova?
a H nuclear fusion explosion on a white dwarf
What caused the rapid spin of neutron star that we see as a pulsar?
The conservation of angular momentum during the collapse of the original star’s core
