| A | B |
|---|
| Constellation (def.) | a group of stars that appear to form a pattern in the sky. |
| Total number of constellations | 88 |
| Best known constellation | Big Dipper |
| Circumpolar constellations | Ursa Major Ursa Minor Cassiopeia |
| Number or stars seen depends on | observers latitude |
| Circumpolarisation is caused by | earth rotating its axis |
| Earth turns | west to east |
| What direction does the sky appear to turn | east to west |
| Big Dipper is where in the sky in the fall | northern horizon |
| Big Dipper is where in the sky in the spring | high over head |
| Cassiopeia in the fall | straight overhead |
| Cassiopeia in the spring | above the northern horizon |
| The changes in postion of constellations is caused by | the changing positions of earth's orbit around the sun |
| Stars that make up the Summer Triangle | Vega-in Lyra the Harp, Altair-in Aquila the Eagle, and Deneb- top of Northern Cross, part of Cygnus the swan |
| Most famous winter constellation | Orion the Hunter |
| 3 stars in the belt of Orion can find what 2 constellations | Canis major and Taurus the Bull and the Pleiades Star Cluster |
| Closest star to earth | sun |
| Average distance | 150 million km |
| 150 million Km equals how many au | 1 Au |
| Light Year (def) | distance light travels in a year |
| The bright red super giant star found forming Orion's right shoulder | Betelgeuse |
| 7th brightest star in the night sky | Rigel |
| How many minutes does it take for light to reach Earth | 8 minutes |
| 3 things the luminosity of the star depends on. | Surface temperature, Color, Disitance from us |
| Put star colors in order from hottest to coldest. | Blue, Yellow, Red |
| Spectrum Analysis(def) | dark line spectra that helps astronomers determine the composition of stars |
| Luminosity(def) | how bright a star is, depends on size and temperature |
| Absolute Magnitude(def) | measure of the amount of light it actually gives off if all stars were placed a distance of 32.6 light years away |
| Apparent Magnitude(def) | measure of the amount of light received on Earth |
| Describe the scale of apparent magnitude | Stars below 0 are brightest, each magnitude differs by 2.5, and the 1st magnitude is 100x brighter than 6th magnitude |
| The brightest star in our sky | Sun |
| The 3 kinds of Stars | Red Giant, Super Giant, and Dwarf Stars |
| Red Giant (def and example) | large red star at least 10x diameter of the sun. Ex: Aldebaron |
| Super Giant (def ) | largest of all stars; 100x more luminous |
| Dwarf Stars (3 traits) | less luminous, very dense, remains of a red giant that ran out of fuel; color are red/orange/yellow |
| Variable Stars(def) | change in brightness over regular periods of time |
| Cepheid Variables/Pulsating Stars(def and example) | change in brightness as they expand and contract. Ex. Polaris |
| Eclipsing Binary(def and example) | 2 stars of unequal brightness revolving around each other. Ex. Algol and Perseus |
| Neutron stars (def) | distant heavenly object that emits rapid pulses of light and radio waves |
| Why do twinkling stars occur? | They're due to Earth's atmosphere |
| Nebulae(def) | space gas seen as faint glowing clouds |
| Example of a nebulea | Sword of Orion |
| Diffuse Nebulea(def) | gases glow from stars within them |
| Dark Nebulea(def) | nebula not near a bright star |
| Why do nebulae still hinder star gazing? | They absorb light which passes through them |
| Protostar(def) | shrinking gas balls, caused by a swirl of gas forming dense areas. The gravity of the dense swirl in turn attracts near by gases so a ball forms |
| A new star is born in our galaxy every | 18 days |
| Stable State Star(def) | star that releases energy in enough force to counter balance gravity, star stops contracting |
| Life Cycle of an average star | nebula, protostar, new star/stable state star, red giant, planetary nebula, white dwarf, black dwarf |
| Life Cycle of a Massive Star | nebula, protostar, new star/stable state star, super giant, super nova, neutron star/pulsar, black hole |
| Super Nova(def) | explosion from a massive Super Giant; outer layer blasts away at end of Life Cycle; emits light, heat, X-rays, & neutrinos |
| Black Hole (def) | denser than a neutron stars; light can NOT escape; located by X-rays detection |
| Example of a black hole | Cygnus X1 in Cygnus the Swan |
| galaxies (def) | systems containing millions or billions of stars, gas, & dust held together by gravity |
| Example of a galaxy | milky way |
| 3 major classes of galaxies | elliptical, spiral, and irregular |
| elliptical (def) | shaped like large ovals or football shaped |
| Spiral (def) | pinwheel shaped; our sun is on a sprial arm of the Milky Way; most common |
| Irregualar (def) | many different shapes that aren't like the other two |
| Quasar (def) | quasi stellar radio source, very far away, but the most luminous objects in the universe, thought to be galaxies with huge black holes in the center |
| Diagram that compares star brightness (absolute magnitude) to a star temperature | Hertzsprung-Russel Diagram |
| 2 examples of variable stars | Polaris & Betelgeuse |
| 2 types of variable stars | Pulsating & eclipsing binary |
