Astronomy Exam #3 Test Questions
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65 terms
Terms | Definitions |
|---|---|
 The asteroid is located between what? | the orbits of Mars and Jupiter |
| Asteroids which travel about the Sun in Jupiter's orbit are the.. | Trojans |
| Asteroids whose orbits cross the earth's orbit are the... | Apollos |
| The Oort Cloud is.. | .a spherical distribution of distant comets 50000 au from the Sun |
| Comet tails are due to.. | melting and evaporation of ices from the comet nucleus |
| The cause of the meteor showers seen at regular times each year upon earth is most probably... | the earth moving through the remnant dust and rock fragments of an old comet which are orbiting the Sun in the comet's old orbit |
| The composition of a typical asteroid is.. | rock and metal |
| What is the basic difference between comets and asteroids? | Comets are composed of ices while asteroids are composed of rocks/metals |
| What is the Sun's photosphere? | the lowest layer in its atmosphere |
| The temperature of the Sun's photosphere is.. | 5800 K |
| The granulation in the Sun's photosphere is due to.. | convective gases |
| What type of brightness distribution does on see towards the edge of the Sun? | decreasing brightness |
| What is the name of the layer of the Sun's atmosphere that appears as pink/red ring during a total solar eclipse and whose spectrum is an emission-line spectrum? | chromosphere |
| What is the name of the flame-like structure in the Sun's chromosphere? | a prominence |
| What is the corona on the Sun? | the Sun's outermost atmosphere |
| What is the temperature of the Sun's core? | 15,000,000 K |
| Sunspots are... | cooler, darker, regions in the Sun's photosphere |
| What is the average length of time from one maximum in the number of sunspots on the Sun to the next maximum? | 11 years |
| Who discovered that the Sun rotates? | Galileo |
| The rotation of the Sun is... | fastest at the equator, slower at mid-latitudes, and slowest near the poles |
| What is the rotation period of the Sun? | about one rotation per month |
| The Sun's______is the cause of its sunspots. | magnetism |
| What is the highest temperature region in the Sun's atmosphere? | corona |
| The solar wind is... | a gentle outflow of gases from the corona |
| What is nuclear fusion? | two nuclei sticking together to form a new, heavier nucleus |
| What process provides the power for the Sun? | the fusion of hydrogen into helium |
| The total time that the Sun will spend converting hydrogen to helium in its core is.. | 10 billion years |
| What does "hydrostatic equilibrium" mean? | the balance of gravity inward and gas pressure outward |
| The most abundant atom is the Sun is.. | H (Hydrogen) |
| Apparent magnitude represents the _____ of a star. | observed brightness |
| A star of apparent magnitude +5 appears... | fainter than a star of apparent magnitude +3 |
| The absolute magnitude of a star is the brightness the star would appear to have if it were _______ from earth. | 32.6 ly |
| The luminosity of a star is a measure of its... | energy output |
| Spectral sequence (O,B,A,F,G,K,M) represents the ________ of the stars. | temperatures |
| The Sun's spectrum is.. | G2 |
| Which of the following spectral types refers to the hottest stellar surface temperature? | B |
| What are the two physical parameters of stars which are plotted in the Hertzsprung-Russell diagram? | luminosity and temperature |
| What is a white dwarf star? | a star with a size comparable to the earth's |
| The star Arcturus is classified as K2 III, which means that it is.. | a cool giant |
| The giant stars are plotted______in the HR diagram. | above and to the right of the MS |
| Which are the two most abundant elements in the Universe? | hydrogen and helium |
| How do massive stars end their lives? | the explode |
| New stars are formed from.. | huge, cool dust and gas clouds |
| Protostars are... | very young objects, still contracting before becoming MS stars |
| The Orion Nebula is.. | a large gas and dust cloud |
| What is the smallest mass that a star can be, is ________ solar masses. | 0.08 |
| An object is too massive to be a planet but not massive enough to be a star is called_______star | a brown dwarf |
| All stars on the main sequence... | generate energy by hydrogen fusion in their cores |
| What is the most important quantity on which the lifetime of a star depends? | mass |
| Which of the following stars would be classified as a Population II star? | a star with very low abundance of heavy elements |
| Our Sun is a _______ Population Star. | 1 |
| A planetary nebula (ring nebula) is.. | a shell of ejected gases from a dying star |
| Our Sun will end it's life as a... | white dwarf |
| How does a white dwarf generate its energy? | it no longer generates energy |
| The light from the most recent supernova, which was visible to the naked eye arrived at earth in.. | SM1987 A |
| The Crab Nebula is.. | a Supernova remnant |
| A black hole is so named because... | it possesses a strong gravity |
| What is the escape velocity from inside a black hole? | greater than the speed of light |
| The Milky Way is a _________ galaxy? | spiral |
| Where is the Solar System located in our Galaxy? | in the galactic disk |
| The Large Magellenic Cloud is example of what type of object? | irregular galaxy |
| What do cosmologists study? | the origin, structure, and evolution of the Universe |
| Who first proposed that the observed motion of galaxies away from us originated with a colossal explosion that began the Universe? | Edwin Hubble |
| Which elements were created in the Big Bang? | helium and hydrogen |
| A quasar is an especially luminous.. | galaxy |
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