2. What is a star?
- body of gasses that give off “tons of” energy (light & heat)
- clusters = those little specks in the sky that we see may really be more than one star….

3. PHYSICAL PROPERTIES OF STARS --
1. Differ in SIZE
2. Differ in COLOR
3. Differ in D I S T A N C E from us
4. Differ in COMPOSITION
5. Differ in BRIGHTNESS

4. Our Sun in considered an average-sized star!
The diameter of our sun is about 109 times the diameter of the Earth!
It has been burning for about 5 billion years. It is only middle-aged. It will burn for about 5 billion more years!!
X 109 =

5. How Are Star Sizes Like Celebrities?
Sometimes the larger the star, the shorter the life span.
This is like the bigger the celebrity (more famous), the shorter their life span!
Ex. James Dean, Chris Farley

6. Function of how LARGE the star is, how OLD it is, and how FAR AWAY.
BRIGHTNESS
Function of how LARGE the star is, how OLD it is, and how FAR AWAY.

7. THE STAR IS TO OBSERVERS ON EARTH
APPARENT MAGNITUDE -
IS HOW BRIGHT
THE STAR IS TO OBSERVERS
ON EARTH

8. Size and closeness can effect apparent magnitude
the brightness how WE see it
the brightest star in a constellation is called the ‘alpha’, then ‘beta’, etc…
Size and closeness can effect apparent magnitude

10. Distance to Stars
Our Sun is the closest star at 93 million miles distance. Next is Alpha Centauri at a distance of 4.27 light years. A light year is 5.88 trillion miles.

11. Stellar Parallax
Parallax = shift in angle that occurs when a nearby object is seen against a distant backdrop from two different perspectives

12. is a star’s apparent brightness if we could position the star 32
is a star’s apparent brightness if we could position the star 32.6 light-years away (the distance that is the furthest star we can see from Earth)
Absolute Magnitude

13. THERE ARE DIFFERENT WAYS TO MEASURE STAR BRIGHTNESS :

14. -depends on SIZE and TEMPERATURE

15. COLOR Yes, stars have different colors!
The temperature of the star determines its color.

16. Star Color if you look close enough…you’ll see colors….
blue = HOT = 17,000o
red = not so hot = 1,700o
Our sun = orange
~ 10,000o

17. What are the Star Colors?
Blue
White
Yellow
Orange
Red
Hottest
Coolest

18. Star patterns :
1000’s of years of observations - want to organize what they saw
constellations = they are named after animals, greek gods and legendary heroes
there are 88 named constellations

19. What should be the brightest star for us?
THE SUN!
it’s the closest - so it should appear the brightest
BUT - it’s just average in reality
ABSOLUTE magnitude = real brightness

20. -

21. R U S E L D I A G M
H e r t z s p r u n g

22. C. 1-2% heavy elements like IRON, TITANIUM, CALCIUM & SODIUM
Composition
A. 70% HYDROGEN
B. 28 % HELIUM
C. 1-2% heavy elements like IRON, TITANIUM, CALCIUM & SODIUM
D. 2 % other heavy elements

23. The light from glowing elements can be analyzed with a Spectroscope
Every element has its own characteristic color when made to emit light.
The light from glowing elements can be analyzed with a Spectroscope
Spectrum

24. Viewed from these two different locations, a nearby star would appear to shift position with respect to more distant stars
The bigger the shift, the closer the start is to earth