Transcript Main Sequence Star

STARS
• Ball of gases, mostly hydrogen
and helium that give off
energy
• A.
Color- determined by
surface temperature.
• 1. Blue- young and hot >30,000
degrees
• Ex. Rigel
• 2. White - usually old and
hot 10000>7500
Ex. Sirius
• 3. Yellow – Average
temperature and middle age
6000>5000
• Ex. The sun
•4 – Red- coolest and
growing old
•Ex. Betelgeuse
4000>1000
• B.
DISTANCE FROM
EARTH
• 1. MEASURED IN LY
– DISTANCE LIGHT TRAVELS IN ONE
YEAR
• 6,000,000,000,000 MILES
2.
MEASURED BY
USING PARALLAX-
• MEASURES THE DISTANCE BY USING
THE APPARENT SHIFT IN MOTION over
time
C. Star’s Brightness
• 1. Luminosity or absolute
magnitude.
– A. Actual brightness of the star
– B. found by using the distance and
apparent magnitude.
• 2. Apparent Brightness
– A. The brightness we see from
earth
– B. Depends on size, distance and
surface temperature.
Constellationgroup of stars that form a pattern
D. Classification
• 1. H. R. diagram (Hertzsprung –
Russell)
• 2. Classifies by surface temperature
and absolute magnitude.
• 3. Main sequence stars- stars of
similar composition and size
– A. “average” stars
• 4. Outside of main sequence
– A. Red super giants and red
giants
– B. Blue Giants.
– C. White Dwarfs
Betelgeuse
Rigel
Betelgeuse
Sun
Sirius
Jansky 1905-1950
• Discovered radio
waves in space
Reber- 1911• Built the first radio
telescope
Collects radio waves
from space
Can be used at anytime or
weather
VLA in New Mexico
ASTRONOMICAL INSTRUMENTS
OPTICAL TELESCOPES
1. REFRACTING TELESCOPE
**uses lenses to
bend light to a
focus point
person
2. Reflecting Telescope
– Uses mirrors
– Concave mirror
reflects light to a
flat mirror
– Ex. Hubble Space
Telescope
• Hale telescope
Spectroscope
• Attaches to an
optical
telescope
– Analyzes light
from the stars
Bright line spectrum
• Separates visible light
by its different
wavelengths
• Each element is then
identified by its own
spectrum
• Shows direction,
movement and
composition
Spectrum___
Ultraviolet
shortest
Infrared
^
Electromagnetic Spectrum
All radiant energy that
travels the speed of light
in waves
longest
Longest to shortest wavelength
DOPPLER EFFECT
**THE APPARENT SHIFT IN
WAVELENGTH DUE TO A
MOVING OBJECT
Red shift- moving away
Blue shift- moving toward
E. Life Cycle Of Stars
• STEP 1. Begins as a nebula- a cloud of dust
and gas.
• STEP 2. Protostar- gravity forms a ballshaped pocket and temperature
increases.
STEP 3. Nuclear fusion
• 4 hydrogen fuse to make helium plus
energy
• Occurs in the core
• Must be 10 mil
– degrees C
STEP 4. Main Sequence Star
• Must have enough mass to have nuclear
fusion for its energy
STEP 5. RED GIANTS
a) Size of giants depends on
the initial mass
b) Could be a super red giant
like Betelgeuse
STEP 6. Supernova or white
dwarf
• a) white dwarf- small, hot, older
star
– 1. Ex. Sirius or the Sun
• b) supernova- gigantic
explosion of a large mass
star like Betelgeuse
• Chinese recorded one in 1054 AD
Supernova Feb.24, 1987
170,000LY
c) NEUTRON STAR
1. Extremely dense; like the
mass of our sun into a 8 mi
diameter
• d) Black hole• 1. An object so dense that not
even light can escape its surface
QuasarsVery powerful
source of
energy
most distant
objects in
space
• Pulsars– a neutron star
that spins
rapidly and
sends out radio
waves
GALAXIES
3 TYPES
• SPIRAL- 2-4 arms
– EX. ANDROMEDA
• IRREGULAR –
– EX. MAGELLANIC CLOUDS
• ELLIPTICAL