Term
| A solar-mass star will evolve off the main sequence when |
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Definition
| it builds up a core of inert helium |
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Term
| a star is on the horizontal branch of the HR diagram, which statement is true |
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Definition
| it s burning both hydrogen and helium |
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Term
| which is used observationally to determine the age of a star cluster |
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Definition
| the luminosity of the min-sequence turn off point |
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Term
| which of these events is not posible |
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Definition
| white dwarfs and companion stars producing recurrent type I* supernova events |
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Term
| of the elements n your body, the only one not formed in the stars is |
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Definition
|
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Term
| for a white dwarf to explode entirely as a type I supernova, its mass must be |
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Definition
| 1.4 solar masses, the Chandrasekhar limit |
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Term
| which of these evolutionary paths is the fate of our sun |
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Definition
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Term
| an iron core cannot support a star because |
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Definition
| iron cannot fuse with other nuclei to produce energy |
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Term
| the helium flash converts helium nuclei into |
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Definition
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Term
| which stars in globular clusters are believed to be examples of merger |
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Definition
|
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Term
| the brightest star in a young open cluster will be |
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Definition
| massive blue main sequence stars |
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Term
| when the outer envelop of red giant recedes, the remaining carbon core is called a |
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Definition
|
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Term
| type II supernovae occur when their cores start making |
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Definition
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Term
| what can yuo conclude about a type I supernova |
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Definition
| it was originally a low-mass star |
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Term
| can a star become a red giant more than once |
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Definition
| yes, before and after the helium flash |
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Term
| compared to cluster containing type O and B stars, a cluster with only type F and cooler stars will be |
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Definition
|
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Term
| the temperature is needed to fuse helium into carbon |
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Definition
|
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Term
| a star spends most of its life |
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Definition
|
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Term
| as a star's evolution approaches the type II supernova, we find |
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Definition
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Term
| a surface explosion on a white dwarf, caused by falling matter from the atmosphere o its binary companion, creates what kind of object |
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Definition
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Term
| which of these is true of the planetary nebulae |
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Definition
| they are ejected envelopes surrounding a highly evolved low-mass star |
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Term
| hen a low mass star first runs short of hydrogen in its core, it becomes brighter because |
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Definition
| the core contracts, raising the temperature and extending the hydrogen burning shell outward |
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Term
| which of these does not depend on a close binary system to occur |
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Definition
|
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Term
| as a 4-10 solar mass star leaves the main sequence on its way to becoming a red supergiant, itsluminosity |
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Definition
|
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Term
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Definition
| if the beam sweeps across us , we will detect a pulse of radiation |
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Term
| what can we detect from matter that has crossed an event horizon |
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Definition
|
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Term
| x-ray bursterd occur in binary star systems. the two types of stars that must be present to make-up such an object are |
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Definition
| a main-sequence or giant star and neutron star in a mass transfer binary |
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Term
| which of these is not an argument for Cygnus X-1 being a black hole |
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Definition
| the mass of the visible star is greater than that of the x-ray source |
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Term
| most pulsars are observed only as _______ sources |
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Definition
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Term
| the mass range for neutron stars is |
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Definition
|
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Term
| if the sun were replaced by a one-solar mass black hole |
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Definition
| we would still orbit in a period of one year |
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Term
| in a neutron star , the core is |
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Definition
| made of compressed neutrons in contact with each other |
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Term
| if the light from a distant star passes close to a massive body, the light beam will |
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Definition
| bend toward the star due to gravity |
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Term
| an object more massive than the sun, but roughly the size of a city is |
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Definition
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Term
| the schwartzschild radios for a 12 solar mass star is |
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Definition
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Term
| as a spaceship nears an event horizon, a clock on the spaceship will be observed |
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Definition
|
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Term
| what explanation does general relativity provides for gravity |
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Definition
| gravity is the result of curved spacetime |
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Term
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Definition
|
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Term
| what would happen if more mass was added to a 1.4 solar-mass neutron star |
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Definition
| it would low off mas as an x-ray buster |
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Term
| a method for identifying a black hole is to |
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Definition
| look for its effects on a nearby companion |
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Term
| the densely packed neutrons of a neutron star cannot balance the inward pull of gravity if the total is |
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Definition
| greater than schwartzchild's limit of 3 solar masses |
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Term
| which are the two most popular candidates for gamma-ray busters |
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Definition
| hypernova making a blackhole, and merger of two neutron stars |
|
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Term
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Definition
| spin very rapidly when they are young |
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Term
| which statement about gamma ray bursters is not correct |
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Definition
| they are scaled up x-ray bursters, with more massive objects |
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Term
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Definition
| very strong bipolar magnetic fields |
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Term
| which statement about black holes is true |
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Definition
| their escape velocity is greater than the speed of light |
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Term
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Definition
| rotation periods comparable to the sun |
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Term
| you would expect millisecond pulsars to be |
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Definition
| part of the binary system |
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Term
| which method relies o the mass of a dark object revealing its presence |
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Definition
| temporary brightening of a distant star by gravity lens |
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Term
| what two observations allow us to calculate mass of the portion of the galaxy within the sun's orbit |
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Definition
| the sun's orbital velocity and its distance from the galactic center |
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Term
| what observation suggests the ass of the galaxy goes much farther out than its visible disc |
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Definition
| the rotation curve of the outermost portions of the disc |
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Term
| which is the correct description of the sun;s location within the milky way |
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Definition
| in the disc and about one-half a galactic radious from the center |
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Term
| between us and the galactic centre, the milky way has a mass of |
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Definition
|
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Term
| what is one f the differences between Cephedis and RR lyrae variables |
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Definition
| the RR Lyrae stars have much shorter periods on the main sequence |
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Term
| if the light from a distant star passes close to a massive body, the light beam will |
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Definition
| bend towards the star due to gravity |
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Term
| which of these does not exist |
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Definition
| a 1.5 solar mass white dwarf |
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Term
| in the formation of our galaxy, the _________formed first |
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Definition
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Term
| which statement about population II is false |
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Definition
| at almost five billion years old, our sun must belong to this older pop |
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Term
| galactic disks appear blue because |
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Definition
| O and B blue giants are much brighter than G,K, or M dwarfs |
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Term
| which of these variable stars would be classified as a Cepheid |
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Definition
| a K giant with a period of 14 years |
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Term
| why was Herschel strategy for mapping our galaxy flawed |
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Definition
| he relied on visual wavelengths which are obscured by dust. |
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Term
| the radio source _________ is located in a place consistent with the center of our galaxy |
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Definition
|
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Term
| Density waves may explain |
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Definition
| the spiral arm structure of the Galaxy |
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Term
| The Galactic Year is the time for our solar system to orbit the Galaxy; it is about |
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Definition
|
|
Term
| ) Most of the mass of our Galaxy lies |
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Definition
| outside the luminous part of the Milky Way Galaxy |
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Term
| What is true about the stellar populations in the Galaxy? |
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Definition
| Only old stars are found in the halo |
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Term
| At the center of our Galaxy lies |
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Definition
| a black hole of millions of solar masse |
|
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Term
| ) Which statement is true? |
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Definition
| The bright blue stars that dominate the sky are Population I stars. |
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Term
| All RR Lyrae stars have about the same |
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Definition
| luminosity of about 100 Suns |
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Term
| most of the new star formation in the galaxy is found in the |
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Definition
|
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Term
| which of these variable stars would be classified as a RR Lyrae |
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Definition
| an F giant with a period of 14 hours |
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Term
| a star in the instability strip of the H-r diagram would |
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Definition
| vary in both temperature and radious |
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