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 Discovered radio waves in space

Reber 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___

All radiant energy that travels the speed of light in waves Electromagnetic Spectrum shortestlongest Infrared Ultraviolet ^

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 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, ,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