Stars Diamonds of the sky
Stars are __________? “Fireflies… fireflies that got stuck up in that big bluish- black thing.” “Kings from the past looking down on us.” “Balls of gas, burning billions of miles away.”
Stars Spheres of gas that produce energy by fusion
Nuclear fusion Nuclear fusion is a nuclear reaction in which two or more nuclei collide at a very high speed and join to form a new type of atomic nucleus.
Nuclear fusion Helium is the fuel for stars. Examples Hydrogen + Hydrogen = Helium Hydrogen + Helium = Lithium Helium + Helium = Beryllium Helium is the fuel for stars.
Classification of Stars Based on: Mass (small large) Age (young old) Composition (amount and kind of material) Temperature (hot cool)
Temperature (hot cool) Purple 35,000oC Blue Green Lt. Yellow Dk. Yellow Orange Red 3,000oC
White light A combination of all colors of light “Rainbow” – white light separated into colors
Black line spectrum When an object is heated and glows, its spectrum shows a specific pattern of black lines. Can be used to identify substances Emission Spectrum Absorption Spectrum or Black Line Spectrum
A star is born Life and death of a star
Stellar Nursery Stars are born from a nebula (plural = nebulae) A nebula is a cloud of gas and dust (solids)
Mature star Light and heat given off (think of our sun) Longest stage of a star’s life 3 sizes: Average (our sun), huge, or giant
Red giant For small/medium stars (up to 1.5 times our sun): 1st stage in death of a star Star swells to gigantic size (200x its normal size) After a while, the hydrogen will run out and fusion will stop…
Collapse! Planetary nebula 2nd stage in death of a star Light and heat greatly decreased Pressures of gravity become imbalanced
White dwarf Black dwarf Final stage in death of star 3rd stage in death of a star Star shrinks to small, hot star Size of small planet Black dwarf Final stage in death of star No light or heat given off
Massive Stars Bigger than average….
Red supergiant For giant and supergiant stars (over 1.5 times our sun): 1st stage in death of a star Star swells to gigantic size (even more than the red giant) After a while, the hydrogen will run out and fusion will stop…
Collapse! Supernova 2nd stage in death of a star Star explodes
Neutron Star Giant stars (1.5 to 3 times the size of our sun): Form a neutron star – a star where the protons (positive charge) and electrons (negative charge) have fused to become neutrons (no charge)
Black Hole Supergiant stars (over 3 times the size of our sun): Form a black hole – a place where the gravitational force is so great that not even light can escape.