Download Groups of Stars

Stars
Astronomy

The study of space
How astronomers measure
distance

1. Light years– The
distance light travels in
one year

9.461x 1012 km
Measuring distance cont

2. Parsec (pc) – 3.26 light years
What if we cant tell
exact distance?
Parallax
The shift of nearby stars with the motion of the
Earth.
The closer the star the more it moves in the
night sky in a smaller time
Groups of Stars
Constellations– Groups of stars named by
ancient people
1.
88 constellations
2.
Your location and the time of year determine
which constellations can be seen
**Circumpolar Constellations rotate around the poles
and can always be seen (Little dipper and
Southern Cross)
1.
Groups of stars cont.
2. Clusters– Any group of stars gravitationally
bound to each other. Some are
constellations some are not
Groups of stars cont.
3. Binaries– Two stars that rotate around each
other (To the eye they look like 1 star)
What are the different aspects of
stars we could look at?
Properties of Stars
Diameter
Brightness
Energy output
Surface temperature
** Mass
** Composition
Magnitude
Apparent Magnitude: How Bright a star
appears (doesn’t take distance into account)
Magnitude
Absolute Magnitude– Measures brightness
from 10 pc
** Can only be calculated if the distance from Earth
is known
Luminosity
The amount of energy from the surface of the
star
** The magnitude and distance must be known
to calculate
** Measured in watts (Joules/ second)
Classifying stars
Stars get a letter and a number
Letters are based on their temperature (spectral
type)
Classifying Stars continued
Numbers are based on their absolute magnitude
And plotted on the Herzsprung-Russell diagram
Temperature vs. Magnitude
Types of stars
Main Sequence Stars– Stars that run a normal
pattern in cooling and loosing magnitude
Types of Stars
Red Giants– Large, cool, luminous Stars
(Doesn’t fuse hydrogen, fuses larger elements
instead)
Types of Stars
White Dwarfs– Small, hot, dim stars
(Doesn’t fuse hydrogen)
Fusion
How energy is
generated on the
surface of stars
** Hydrogen atoms
collide and make
Helium
Life Cycle of Stars
Formation– All stars
begin as a cloud
of dust called a
Nebula
Nebulas
Clouds of dust that
collapse on its self
forming a PROSTAR
Eventually the prostar
will get hot enough to
star the fusion
process
The amount of mass determines the life
of the star
Smallest Stars (Red)
1.
2.
3.
4.
5.
Nebulas
Prostars
Main sequence
White dwarf
Black Dwarf
Next largest (Yellow)
1.
2.
3.
4.
5.
6.
Nebula
Prostar
Main sequence
Red Giant
White Dwarf
Planetary nebula (will be recycled into a
new star)
White Stars (3x the mass of our
sun)
1.
2.
3.
4.
Nebula
Prostar
Red supergiant
Neutron Star (will
start over into a
nebula)
Blue stars (The largest 9x the
size of our sun)
1.
2.
3.
4.
Nebula
Prostar
Red supergiant
Black hole