1. The “Life” of Non-living Stars
By Erin Belluomini

2. Why do stars look different colors in the night sky?
Stars are different colors
Colors indicates the temperature of the star
Red stars are the coolest
Blue stars are the hottest

3. Fascinating Examples Orion is a well-known winter constellation
Orion contains a large red star known as Betelgeuse
Orion also contains a blue star known as Rigel
Betelgeuse and Rigel differ in their temperatures too

4. From what elements are stars created?
Studying light from a star can tell us what elements are in stars
A continuous spectrum shows all the colors when white light passes through a prism
Elements emitted from stars do not show all the colors of the spectrum
The colors that get absorbed tell scientists from what elements the star is made

5. Common Elements of Stars
Hydrogen and Helium are the most abundant elements in stars
Stars contain other trace elements
Carbon, nitrogen and oxygen are the most common

6. How do scientists classify stars?
Originally stars were classified by the elements they contained
Astronomers created system based on brightness…absolute magnitude
Positive #s are dim, negative #s are bright
Stars are classified by temperature

7. Why do we see different constellations throughout the year?
Earth revolves around sun
Earth’s tilt and revolution cause season’s
Earth faces a different part of sky each season
A different constellation is seen at different times of the year

8. Motion of and Distance to Stars
Stars closer to Earth seem to move
Stars further away seem to stay in one place
Known as parallax
Parallax used to calculate actual distances to stars
Distance measured in light-years
A light-year is the distance light travels in one year….very fast!

9. Our Sun’s Color and Classification
Our sun is Earth’s closest star
Our sun’s color is yellow
Our sun’s temperature is 6000 C
Hydrogen, Helium, Calcium and other heavier elements make up our sun
Our sun is a class G star
Our sun is about +4.8 in absolute magnitude

10. Do stars “live” forever?
Stars do not live forever
Stars can exist for billions of years
Stars get different classifications as they age
To stay alive, stars must generate energy through nuclear fusion

11. Nuclear Fusion How the sun generates energy
Process where two hydrogen nuclei fuse to form helium
The beginning of a stars life
Click to view video clip!

12. The Life Cycle of Stars Stars begin life as a ball of gas and dust
Temperatures reach 10,000,000 C
Nuclear Fusion begins
This stage known as a Protostar

13. Main Sequence
Main Sequence is the second and longest stage of a star’s life
Hydrogen continues to fuse into helium
Size of star changes very little during this stage

14. Giants and Supergiants
Giants and Supergiants result when a star uses all the hydrogen in its core
Star grows very large and cools

15. The H-R Diagram An H-R Diagram
Shows relationship between surface temperature and absolute magnitude

16. Massive Stars
Use their hydrogen much more quickly than stars like our sun.
Generate more energy but have shorter lives.
Meet dramatic deaths as Supernova explosions!
Become neutron stars, pulsars and maybe black holes.

17. Our Sun’s Age Our Sun was born from a solar nebula.
Our Sun is about half way through it’s life cycle.
Our Sun will not live forever!
How will our Sun die?
The Click of Death

18. Why We Study Stars
The structure and composition of the universe can be learned by studying stars and galaxies and their evolution.
Understanding the properties of stars provides us with an understanding of our sun, which is a star!
The properties of the sun affect Earth directly, so it is important to know them.

19. Fun Facts
The brightest star discovered is at least 150 times as large and probably 40 million times as bright as our sun! (Break out those sunglasses)!
Sir Isaac Newton was the first to discover that white light is composed of different colors!

20. Comprehension Question
1) What are the two elements that commonly make up stars?
a) Hydrogen (H) and Oxygen (O)
b) Hydrogen (H) and Helium (He)
c) Helium (He) and Nitrogen (N)
d) Hydrogen (H) and Nitrogen (N)

21. Congratulations you are a Sun God or Goddess!
Correct!
b) Hydrogen and Helium are the most common and abundant elements in stars!
Congratulations you are a Sun God or Goddess!

22. Incorrect!
Try again! Remember that stars undergo nuclear fusion which means one element fuses to become another! Much energy is released in the process!
Hint: What two elements are close enough to each other on the periodic table to be able to undergo nuclear fusion.

23. Comprehension Question
2) What will be the next stage of our sun’s life cycle?
A white dwarf
A pulsar
A red giant
A protostar

24. Correct Again!
Our star will become a red giant once all of it’s hydrogen in its core is used, its helium has begun to fuse and the center of the star shrinks. The Sun will grow very large and will cool down!
You are definitely a “STAR” student!

25. Incorrect!
Remember that currently our star is a main-sequence, average size, yellow star!

26. Works Cited

27. My vacation
Look at this sunset!