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29 Cards in this Set
- Front
- Back
X-ray bursters 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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a main-sequence or giant star and a neutron star in a mass transfer binary.
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In a neutron star, the core is
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made of compressed neutrons in contact with each other.
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What can we detect from matter that has crossed an event horizon?
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nothing
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The densely packed neutrons of a neutron star cannot balance the inward pull of gravity if the total mass is
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greater than Schwartzschild's limit of 3 solar masses
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What can you conclude about a Type I supernova?
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It was originally a low-mass star
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Which stars in globular clusters are believed to be examples of mergers?
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Blue stragglers
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As a spaceship's velocity gets closer to the speed of light with respect to an external observer, that observer will report that
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its length will decrease and its clock will run more slowly.
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If light from a distant star passes close to a massive body, the light beam will
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bend towards the star due to gravity.
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In the Lighthouse Model,
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if the beam sweeps across us, we will detect a pulse of radiation.
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An observer on a planet sees a spaceship approaching at 0.5c (where c is the speed of light). A beam of light projected by the ship would be measured by this observer to travel at
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c.
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Which is used observationally to determine the age of a star cluster?
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the luminosity of the main-sequence turn-off point
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Most pulsars are observed only as ________ sources.
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radio
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If the Sun were replaced by a one-solar-mass black hole,
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we would still orbit it in a period of one year.
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What would happen if more mass was added to a 1.4-solar-mass neutron star?
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It would blow off mass as an X-ray burster.
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Two important properties of young neutron stars are
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extremely rapid rotation and a strong magnetic field.
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Which statement about gamma ray bursters is not correct?
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They are scaled up X-ray bursters, with more massive objects involved.
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Which are the two most popular candidates for gamma-ray bursters?
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hypernova making a black hole, and merger of two neutron stars
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Which of these events is not possible?
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white dwarfs and companion stars producing recurrent Type I supernova events
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The mass range for neutron stars is about
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1 to 3 solar masses.
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Which of these does not depend on a close binary system to occur?
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a Type II supernova
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For a white dwarf to explode entirely as a Type I supernova, its mass must be
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1.4 solar masses, the Chandrasekhar limit.
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Pulsars
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spin very rapidly when they're young.
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A hypernova creates
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a black hole.
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You would expect millisecond pulsars to be
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part of a binary system.
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Compared to a cluster containing type O and B stars, a cluster with only type F and cooler stars will be
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older.
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Type II supernovae occur when their cores start making
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iron.
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A recurrent nova could eventually build up to a
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Type I supernova.
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Which statement about black holes is true?
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Their escape velocity is greater than the speed of light.
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What explanation does general relativity provide for gravity?
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Gravity is the result of curved spacetime.
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