Download Star Notes (ppt)

There are
MORE than
200 billion,
billion stars in a
universe. Most
stars contain
mainly
hydrogen and
helium.
I.
Color of a star: tells what the
surface temperature of the star is
HOTTEST STAR: shines with a
blue-white light
COOLEST STAR: shines with a red
light
Star Temperatures
http://www.eudesign.com/mnems/startemp.htm
http://www.geocities.com/SummerDale33/Mnemonic.html
Star
Type
OUR
SUN
O
B
A
F
G
K
M
K
Temperature
◦C
◦F
> 25,000
> 24,727
> 44,540
11,000 – 25,000
10,727 – 24,727
19,340 – 44,540
7,500 – 11,000
7,227 – 10,727
13,040 – 19,340
6,000 – 7,500
5,727 – 7,227
10.340 – 13,040
5,000 – 6,000
4,727 – 5,727
8,540 – 10,340
3,500 – 5,000
3,227 – 4,727
5,840 – 8,540
< 3,500
< 3,227
< 5,840
Color
blue
blue
white
yellow
yellow
red
red
II. Magnitude: star’s brightness (luminosity)

Absolute Magnitude



The actual brightness of a star
How bright it IS
Apparent Magnitude


The brightness of a star as viewed from Earth
How bright it SEEMS
Apparent magnitude affected by:
–Distance
–Size
–Temperature
H-R Diagram
--illustrates the relationship that exists
between the average surface temperature
of stars and their absolute magnitude.
As absolute magnitude(brightness) increases,
surface temperature increases.
Star Brightness vs Temperature