Transcript Stars 19.1

 Name
the closest star to Earth.
Stars
The Spectrum
 Scientists
break down the light from a star
into colors using a spectrum
 The spectrum colors from the light show
the star’s temperature and composition.
 The pattern of lines also show some of the
elements in the star’s atmosphere.
How do we classify stars?
Temperature:
**Hottest stars
are BLUE or
WHITE
**Coolest stars
are RED or
ORANGE
How do we classify stars?
Brightness:

The amount of light the star gives off
 Depends on size and temperature
 Large cooler  bright
 Small hot  bright
Apparent Magnitude: How bright the star appears
from Earth; closer = brighter
Absolute Magnitude: How bright the star is actually
shining – hard to determine
Measuring Distance to Stars
in light years – LY
 LY – the distance light travels in 1 yr. It is a
measurement of distance not time.
 300,000 km per second!
 Closest star is Proxima Centauri at 4.2 LY
away. Traveling 300,000 km per second it
would take 4.2 Earth years to get there!
 Measured