STARS Ball of gases, mostly hydrogen and helium that give off energy A. Color- determined by surface...
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Transcript of STARS Ball of gases, mostly hydrogen and helium that give off energy A. Color- determined by surface...
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.
Constellation- group 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
Sirius
Sun
Jansky 1905-1950• Discovered radio
waves in space
Reber- 1911-• Built the first radio
telescopeCollects 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___
All radiant energy that travels the speed of
light in waves
Electromagnetic Spectrum
shortest longestInfraredUltraviolet
^
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 ball-shaped 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 GIANTSa) 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
• Pulsars- – a neutron star
that spins rapidly and sends out radio waves
Quasars-
Very powerful source of
energy
most distant objects in space
GALAXIES
3 TYPES• SPIRAL- 2-4 arms
– EX. ANDROMEDA
• IRREGULAR – – EX. MAGELLANIC CLOUDS
• ELLIPTICAL