Life Cycle of Stars

What is parallax, and how do astronomers use it to determine the distance to a star?

Calculate distance from stars to earth

Why are closer stars easier to measure using parallax than very distant stars?

Show larger parallax angles 

What is a light-year? Explain what it measures. 

Distance light travels in one year, approximately 9.5 trillion kilometers

When astronomers cannot use parallax to determine a star's distance, what other methods can they use?

A lightyear

How can astronomers determine the composition of a star by studying its light?

Determine the star's composition by analyzing the light it emits 

What does the color of a star tell astronomers about the star?

Color reveals a stars temperature

Describe the relationship between a star's temperature and its color. Which colors represent the hottest and coolest stars?

Temperature gives off a color for the star with red being the coldest and blue being the hottest

Our Sun is classified as a G-type star. What does this tell us about its temperature and color?

Its a yellow star with a low to medium heat

What is the difference between apparent magnitude and absolute magnitude?

Apparent is brightness of star from earth and absolute is the true brightness

Why might a star appear very bright from Earth even if it is not actually one of the brightest stars?

Its closer to us than others

What information is shown on an H-R Diagram?

Size and the heat

How does an H-R Diagram help astronomers classify and understand stars?

Helps them see the size and temp of stars

Where are main-sequence stars located on an H-R Diagram?

In the middle 

Why is a star's mass important in determining how long it will live?

It matter because there is either less or more mass in the star

What is a nebula, and why are nebulae important to the formation of stars?

Interstellar cloud of gas and dust found in space and serve as stellar nurseries where new stars are formed

What is a protostar? How does a protostar form?

Early stage in the formation of a star and they form when gas and dust in a nebula collapse under gravity

What happens to the temperature and density of a protostar as it continues to collapse?

It heats up and gets densers 

What must happen in the core of a protostar before it becomes a main-sequence star?

Nuclear fusion has to happen before 

What happens when hydrogen atoms fuse together inside a star?

Form helium releasing immense energy 

How does a star's mass affect the types of elements that can form inside its core?

Determines which elements are formed and the type of fusion

What two forces are balanced in a main-sequence star?

Gravity and pressure 

Why can a main-sequence star remain stable for such a long period of time?

It has hydrogen fusion 

Compare the lifespans of massive stars and smaller, lower-mass stars. Why is there a difference?

Massive stars live shorter because they burn  fuel quicker and smaller stars burn fuel slowly living longer

What happens to a low- or average-mass star after it uses up the hydrogen in its core?

They become red giants

What is a red giant? Describe its size, temperature, and appearance.

Larger than a main sequence star, become cooler and red

What type of fusion occurs inside a red giant?

Helium

Explain what happens to the outer layers of a red giant near the end of its life.

Becomes a white dwarf

What is a white dwarf? Describe its size, composition, and temperature.

Earth sized star composed of mostly carbon and oxygen

Why does a white dwarf eventually become cooler and fainter?

No further nuclear fusion occurs

What is a red supergiant, and how is it different from a red giant?

Are the biggest stars in the universe,  fuses carbon, oxygen, and iron

Why can massive stars create heavier elements than smaller stars?

Gravity pushes on them harder

What is the significance of iron forming in the core of a massive star?

Cant live anymore

Why are massive stars unable to continue living once they have formed an iron core?

They dont have any more gravtinationl force 

What causes a massive star to eventually undergo a supernova?

They dont have aany more gravittationla force

Describe what happens during a supernova explosion.

Ejects stars mass into space creating shockwaves and a burst of energy

Why are supernovae important to the formation of new stars and planets?

Scatter elements

What happens to the material from a massive star during a supernova?

Either become neutron stars or black holes depending on size

What determines whether the remains of a massive star become a neutron star or a black hole?

Neutron stars happen if solar mass is between 1.4 and 3 and vlack holes are if the mass is more on 3

What is a pulsar, and how is it related to a neutron star?

It spins rapidly and emits beams of radiation

What is a black hole? Explain why light cannot escape from one.

Region of space where gracity is so strong which is why light acnt escape

Describe the complete life cycle of a low- or average-mass star, beginning with a nebula.

Nebula, main sequence, red giant, planetary nebula, white dwarf

Describe the complete life cycle of a massive star, beginning with a nebula.

Nebula, massive main sequence, red supergiant, supernova, neutron star black hole

What is the biggest factor that determines which path a star takes during its life cycle?

Mass

Why do all stars eventually run out of fuel?

They burn out all of there gyrdrogen and then run out of helium in the core

Compare the final stages of a low-mass star with those of a massive star.

Low mass die gently by shedding layers into a palnetary nebula becoming a cool white dwarf

What stage of its life cycle is our Sun currently in?

Main sequence 

How old is the Sun, and approximately how much longer will it remain a main-sequence star?

Alive for 4.6 billion years, and expected tom live for 5 billion more

Describe the stages the Sun will go through after it leaves the main sequence.

Red giant, planetary nebula, white dwarf

What will eventually happen to the Sun's outer layers?

Planetary nebula 

56. What will the final remnant of the Sun be?

A white dwarf