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