W1: Life & Death of Stars

Question 1

During most of their lives, stars produce energy by which process

Answer 1

nuclear fusion: two or more atomic nuclei come together to form a heavier nucleus, releasing a tremendous amount of energy in the process

Question 2

relationship between the lifespan and mass of stars

Answer 2

more massive star = shorter lifespan

less massive star = longer lifespan

Question 3

relationship between the brightness and temperature of stars.

Answer 3

colour of the starts tell about the temperature and age

hotter star = more energy and brighter

cooler star = less energy and dimmer

Question 4

What incredible discovery did Jocelyn Bell Burnell make related to the death of massive stars?

Answer 4

discovered pulsars. helps understand the life cycles of stars especially massive stars

pulsars: fast spinning, highly magnetized, rotating neutron stars

Question 5

What important work did Annie Jump Cannon do for stellar astronomy that we still follow today?

Answer 5

stellar classification system
* helps understand properties and evolution of stars
* provides essential information about a star’s temperature, luminosity, and chemical composition

Question 6

What are the forces within and outside a star that keep it stable during it’s time in the main sequence?

Answer 6

Hydrostatic Equilibrium
- gravitational force (pushing inward) and radiation force (pushing outward)

Question 7

What is a black hole

Answer 7

extremely dense region in space where the gravitational pull is so strong that nothing, not even light, can escape from it.
It’s formed from the remnants of massive stars that have collapsed under their own gravity, creating a point of infinite density known as a singularity, surrounded by an event horizon.

Question 8

reason we can’t see a black hole

Answer 8

b/c it doesnt emit or reflect any light. black holes are completely dark and invisible to the naked eye

their immense gravitational pull traps even light within their event horizon, a boundary beyond which nothing can escape, including the light itself. As a result, black holes are essentially invisible, and we can only infer their presence by observing their effects on nearby matter and light.

Question 9

what happens when you cross the Event Horizon of a black hole?

Answer 9

it’s a one-way journey, no escape. Once you pass this point, you’ll be stretched and torn apart due to extreme gravitational forces, and your fate beyond that point is unknown.

Question 10

Explain what is meant when astronomers say that we are all made of “star stuff”

Answer 10

• the elements and compounds necessary for life and the composition of our world were originally produced within the cores of stars.
• The basic building blocks of matter, such as hydrogen, helium, carbon, oxygen, nitrogen, and many other elements, were created during the life cycles of stars.
• These elements are crucial for the formation of molecules, compounds, and the structure of all living and non-living things.

Question 11

what remains when a very massive star (many times more massive than our own sun) dies?

Answer 11

neutron stars
- very massive star
- have extremely strong gravitational fields and may exhibit properties like fast rotation (pulsars)

black hole
- extremely massive
- create a region of spacetime where the gravitational pull is so intense that nothing, not even light, can escape from it

Question 12

what remains when a sun-like star dies?

Answer 12

Protostar > main sequence star > red giant > planetary nebula > white dwarf

Question 13

determine a stars temperature:

Answer 13

O (High)
B
A
F
G
K
M (low)