stars ball of gases, mostly hydrogen and helium are all stars the same color? no! color- determined...
TRANSCRIPT
STARS• BALL OF GASES, MOSTLY
HYDROGEN AND HELIUM
• Are all stars the same color?• NO!• Color- determined by surface
temperature.
• 1. Blue- young and hottest
• Ex. Rigel (above 30,000 degrees Celsius
• 2. White - usually old and hot
Ex. Sirius (10,000 o
C)
3. Yellow – Average (5000-6000
oC )temperature and middle age
• Ex. The sun
•4 – Red- coolest and growing old •Ex. Betelgeuse less than 3,500 o
C
All radiant energy that travels the speed of
light in waves
Electromagnetic Spectrum
shortest longestInfraredUltraviolet
^
Longest to shortest wavelength
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___
DOPPLER EFFECT
**THE APPARENT SHIFT IN WAVELENGTH DUE TO A MOVING OBJECT
Red shift- moving away
Blue shift- moving toward
DISTANCE LIGHT TRAVELS IN ONE YEAR
• 6,000,000,000,000 MILES (186,000 mi/sec) or • 300,000 km/s
• AU: Astronomical unit • Distance from Earth to Sun
• 149,597,870,700 m or just 1 AU
• Distance is measured by using PARALLAX-
• THE APPARENT SHIFT IN MOTION over time
• Ex. • Hold out one arm and give a thumbs up
• Close one eye and cover the Red Star• Now switch eyes
• That apparent change is parallax!
• 2. Apparent Brightness (Magnitude)
– A. The brightness we see from earth
– B. Depends on size, distance and surface temperature.
C. Star’s Brightness
• 1. Luminosity or absolute magnitude.
– A. Actual brightness of the star
– B. found by using the distance and apparent magnitude.
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
3. Catadioptric Telescope
– Uses mirrors – AND Lenses– Ex. Celestron 8
Problems with Optical telescopes• Light pollution
EM (electromagnetic) spectrum
Jansky 1905-1950• Discovered radio
waves in space 1931
Reber- 1911-2002• Built the first radio
telescope (1937)Collects radio waves from space
Can be used at anytime or weather
VLA in New Mexico
ASTRONOMICAL INSTRUMENTS
Radio Telescopes• Operate in the radio
frequency portion of the EM spectrum where they can detect and collect data on radio sources.
• Used anytime, no light pollution or weather problems
Scientific Terms
a (testable) proposed explanation for a phenomenon
a well-confirmed type of explanation of nature, made in a way consistent with scientific method
"Big Bang theory"
Alvarez hypothesis“Meteor-impact”
describes some aspects of the universe or phenomenon
“gravity”
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
E. Life Cycle Of Stars• STEP 1. Begins as a nebula- a cloud of dust
and gas. (mostly H and He)
• 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
c)No more H(very little), He turns into C
More energy HHe and HeC, gravity cant hold on ahhh!
STEP 6. Supernova or white dwarf
• a) white dwarf- small, hot, older star no shell, only core left to cool
– 1. Ex. Sirius or the Sun (some day)
• 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