Download a star.

STARS
What are stars?
• Stars are huge balls of very hot gas.
• A Constellation is a group of stars that form an
imaginary picture in the sky.
• Some examples include: The Big Dipper, The Little Dipper, Orion, and
Scorpio.
Types of Stars and How
They Form
• Low Mass Stars
• Medium Mass Stars
• High Mass Stars
Low Mass Stars
•
•
•
•
Nebula
Protostar
Main Sequence Star
White Dwarf
• Small, cool stars
• Use hydrogen slowly
• Live more than 30
billion years
Medium Mass Stars
•
•
•
•
•
•
Nebula
Protostar
Main Sequence Star
Red Giant
Planetary Nebula
White Dwarf
• Medium size and
temperature
• Live about 10 billion
years
High Mass Stars
•
•
•
•
•
•
Nebula
Photostar
Main Sequence Star
Supergiant
Supernova
Neutron Star or Black
Hole
• Hottest, most massive
stars
• Shortest lives: just
millions of years
• Use hydrogen quickly
Black Holes
• Formed when a
supernova explodes,
which causes the core
to collapse.
• So dense that even light
can’t escape their
gravity.
Star Properties
Colors and Temperatures
Blue
Hottest
Yellow
Medium temperature
Sun
Red
Coolest
Starlight Brightness
• Apparent Magnitude: How bright a star appears to be
from earth when viewed with the unaided eye.
Distance can cause a dimmer star to appear to be
brighter than a brighter star that is farther away.
• Absolute Magnitude: The amount of light
(brightness) a star actually has. This is an actual
measurement.
When a star forms it begins its “life.”
When a star runs out of fuel, it dies.
So a star has a life similar to a
battery in that it cannot be
recharged. When the battery runs
out of energy, it is finished. Our
sun will run out of energy and it will
be finished too... But this will not
happen for another 5 billion years!
Life cycle of our sun
We are now here