Astronomy 122 – Flashcards
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When visible light passes through a prism of glass, which wavelengths of light are refracted most by the glass?
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the shorter wavelengths (blue)
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The best shape for the cross-section of a large astronomical mirror in order to produce the sharpest images of very distant objects is
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a parabolic shape
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Where are new stars born?
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within dark clouds in interstellar space
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Which of the following types of telescope will suffer from chromatic aberration unless expensive measures are taken to avoid it?
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refracting telescope
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Chromatic aberration occurs in a telescope when
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the different colors of light come to different focal points
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Astronomy from space vehicles is particularly useful because
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the telescope is above the Earth's absorbing and distorting atmosphere and can measure radiation over a very wide wavelength range.
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On the absolute scale of temperature (in degrees Kelvin, or Kelvins), the zero of the scale corresponds to
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the temperature at which the motion of atoms and molecules ceases.
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On the absolute Kelvin temperature scale, the temperature of freezing water is about
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+273 degrees
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As a new star evolves from cool dust and gas to a hot star, the peak wavelength of its spectrum of electromagnetic radiation will change from what wl to what wl
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change from the infrared to the visible wavelengths
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Which of the following are made of "star dust"? a. spiders b. buildings c. the Sun d. all of the above.
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a. spiders b. buildings c. the Sun ----> d. all of the above.
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Increasing the diameter of the mirror or lens of a telescope will:
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improve its resolution
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Refracting telescopes are limited because:
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lenses bend different colors of light different amounts
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Comparing refracting and reflecting telescopes:
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it is practical to build larger reflecting telescopes
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Which of the following types of the electromagnetic radiation could provide the best resolution in the same size instrument?
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visible light
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The Doppler Effect is used by astronomers to determine:
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radial speeds of stars
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A star whose surface temperature is 100,000 K will emit a spectrum whose peak wavelength is
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at ultraviolet wavelengths
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We use radio astronomy because...
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radio waves pass right through dust
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The early workers in spectroscopy (including Kirchhoff with laboratory spectra) discovered which very significant fact about the spectra produced by hot gases, such as elements heated in a flame.
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each chemical element produces its own characteristic pattern of spectral lines.
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Atoms in a hot gas emit a spectrum, which is
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a series of specific colors ("lines"), unique to the type of atom, but fixed in color when gas temperature changes
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The specific colors of light ("lines") emitted by an atom in a hot thin gas (e.g. in a tube in a laboratory or a gas cloud in space) are caused by
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electrons jumping to lower energy levels, losing energy as they do so
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If light from a hot, dense star passes through a cool cloud of gas
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only specific wavelengths of light ("absorption lines") will be removed from the spectrum
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An atom is now known to consist of
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a small, massive, electrically charged core ("nucleus") with electrons surrounding it
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A spectrum consisting of many dark lines superimposed on a continuous spectrum is
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an absorption-line spectrum
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Ionization of an atom occurs when
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an electron is removed from the atom
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Suppose the spectrum of a solar-type star shows an equivalent set of dark absorption lines, but with one exception. Every line appears at a slightly longer wavelength, shifted towards the red end of the spectrum. What conclusion can be drawn from this observation? (Hint: recall the Doppler effect)
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the star is moving rapidly away from the Earth
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Stars that are just being formed are best observed by
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radio waves
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When light from the concave primary mirror of a telescope is reflected by a small secondary mirror through a hole in the primary to its focus, this is called the
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Cassegrain focus
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Who was the first astronomer to build and use a telescope to observe the night sky?
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Galileo
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The reflecting astronomical telescope with an eyepiece at the side is named for?
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Newton
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The Helium atom is composed of
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two electrons and a nucleus of two protons and two neutrons
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Hans Bethe and other physicists explained the source of the Sun's energy as
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the fusion of atomic nuclei
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Choose the correct order of electromagnetic radiations, from shortest to longest wavelength: Visible, Radio, Uv, IR
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UV, visible, IR, radio
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What is the one fundamental difference between x-rays and radio waves?
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their wavelengths are very different
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Refraction is
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the bending of light as it crosses the boundary from one transparent material to another (such as a lens)
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What happens when a beam of white light (containing all colors) is passed through a prism of glass?
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different colors are refracted at different angles to produce a spectrum
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The light-gathering power of a telescope is related directly to
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the area of its primary mirror or lens
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Compared with the 100-inch diameter Mount Wilson telescope, the 200-inch diameter Mount Palomar telescope has a greater light-gathering power, by a factor of
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4
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The major cause of blurring and unsharp images of objects observed through very large telescopes, at the extreme limit of magnification, is
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air turbulence in the Earth's atmosphere
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What is the main reason for combining many radio telescopes together into an interferometer with large distances between telescopes?
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to obtain much sharper images of sources
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The main reason for carrying a telescope and scientific equipment in an aircraft in order to carry out infrared astronomy is
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to avoid the absorbing effects of water vapor upon IR radiation
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Given that a 6000 K surface emits radiation ("blackbody theory") with a peak wavelength of 0.48 microns a 12000 K surface will have a peak _____
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0.24 microns
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Suppose star A has a surface temperature of 6000 K and star B has a surface temperature of 12000 K. Compare the energy emitted per surface area of each star.
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star B will emit sixteen times star A
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Parallax can be used to determine star distances for:
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stars relatively close to the sun
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In understanding stars, the Bohr atom is useful for the following purpose(s):
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it helps us understand the spectral lines
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Radio waves travel through space at what speed?
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at the speed of light, 300,000 km/sec
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The Doppler Effect is the change in the wavelength of light caused by the source in respect to what?
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moving with respect to the observer
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The peak wavelength in the spectrum of light from a star can be used to determine its
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surface temperature
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What special event was observed in the Large Magellanic Cloud in 1987?
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first supernova visible on Earth to the naked eye in 400 years
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The two windows of the atmosphere are
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the optical window and the radio window
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What type of radiation has wavelengths greater than 100 microns?
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radio waves
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What type of radiation has wavelengths in the range of 0.7 microns to 100 microns
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it is infrared radiation
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The typical wavelength of visible light is
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0.5 microns
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What is the name of the large telescope launched from the Space Shuttle in 1990?
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The Hubble Space Telescope
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How many light years in one parsec?
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about 3.3
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Star A appears to have the same brightness through a red and blue filter. Star B appears brighter in the red than in the blue. Star C appears brighter in the blue than in the red. Rank these stars in order of increasing surface temperature.
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B, A, C
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Electronic detectors often used to record telescopic images are
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CCDs
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What new development in telescopes are bringing striking improvements in ground-based optical telescopes?
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active and adaptive optics
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Light with a wavelength of 400 nm (or 0.4 microns) is perceived to be
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violet
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How many more years will the Sun shine (approximately)?
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5 billion years
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Which photon has the highest energy?
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gamma-ray
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An advantage of a visible light telescope is
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the Earth's atmosphere is transparent to visible light
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The best wavelength for penetrating dusty regions of interstellar space, and detecting otherwise hidden objects is
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radio waves
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The Big Bang mostly created which elements?
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hydrogen and helium
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The Earth's atmosphere is opaque to a. gamma-rays b. X-rays c. ultraviolet radiation d. all of the above
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a. gamma-rays b. X-rays c. ultraviolet radiation ----> d. all of the above
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The Earth's turbulent atmosphere will smear point like images of stars into "seeing disks that are how big in diameter
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a few arc seconds in diameter
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What is the approximate frequency of visible light?
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6 x 1014 Hz
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What is the approximate energy carried by a photon of visible light
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4 x 10-19 Joules
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Emission lines from molecules result from a. electron orbital changes b. changes in the vibrational state of the molecule c. changes in the rotational state of the molecule d. all of the above
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a. electron orbital changes b. changes in the vibrational state of the molecule c. changes in the rotational state of the molecule ----> d. all of the above
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A photon of light is emitted from an atom when what happens to the atom
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when an electron drops from an energy state to a lower energy state
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The relationship between energy (E) and the frequency of a photon (f) is
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E = hf
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A photon of wavelength 10 micro-meters is considered what type of wavelength
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infrared radiation
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A spectroscope (or spectrograph) is
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an optical device that records a spectrum
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Different elements can be distinguished by their emission spectrum because why
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they each produce different specific emission line wavelengths
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The width of an emission line can be broadened through a. thermal broadening b. rotational broadening c. collisional broadening d. all of the above
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a. thermal broadening b. rotational broadening c. collisional broadening ---> d. all of the above
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The temperature of a star can be inferred from a. the peak of the continuous spectrum of the star b. the width of the absorption lines in the star's spectrum c. the specific lines that are present in the star's absorption spectrum d. all of the above
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a. the peak of the continuous spectrum of the star b. the width of the absorption lines in the star's spectrum c. the specific lines that are present in the star's absorption spectrum ---> d. all of the above
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Astronomers analyze starlight to determine a star's a. temperature b. composition c. motion d. all of the above
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a. temperature b. composition c. motion ----> d. all of the above
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Compared with slowly rotating stars, the fastest spinning stars have absorption lines that are
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broad and fuzzy
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Compared with a complex atom like neon, a simple atom such as hydrogen has more or fewer excited states?
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fewer excited states
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Light behaves as a wave or particle?
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sometimes as a wave, and sometimes as a particle
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The Big Bang occurred how many years ago?
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about 14 billion years ago
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The distance to the closest star beyond the Sun is about
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4 light-years
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How is a parsec defined?
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the distance which has a 1 arcsecond parallax
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What process has created most of the heavier elements (beyond hydrogen and helium) in the Universe?
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nuclear fusion within stars
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The resolution of a typical radio astronomy telescope for 1 meter wavelength is about
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10,000 arc-seconds
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What type of electromagnetic radiation is made of photons with the lowest energy?
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Radio waves
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What color of visible light has the shortest wavelength?
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Violet
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What molecule in the atmosphere is a strong absorber of infrared radiation?
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Water (or H20)
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The diameter of the primary mirror of the Hubble Space Telescope is 2.4 meters. Calculate the angular resolution for visible light. (Hint: ang. res. (in arc-secs) = 0.25 x wavelength(microns) / diameter(meters) )
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ang. res = 0.25 x 0.5 / 2.4 arc-sec = 0.05 arc-sec
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What was the first astronomical radio source discovered by Karl Jansky?
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The Center of the Milky Way Galaxy
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Calculate the distance of one light year in kilometers, beginning from the speed of light (show the calculation).
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One light-year = the speed of light multiplied by the length of a year = 300,000 km/sec x 60 sec/min x 60 min/hour x 24 hours/day x 365 days = 9.5 x 1012 kilometers
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What effect causes the colors of a moving object to be shifted to red or blue .
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Doppler Effect
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What is the brightest star in the evening sky?
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Sirius
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The most common element of main-sequence stars is
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hydrogen
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The radius of the Sun is about
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700,000 kilometers
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What is the approximate density of dust in the interstellar medium?
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1000 dust particles /km3
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The interstellar gas (by number of atoms) is
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90% hydrogen, 9% helium, traces of other atoms
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HII regions are characterized by
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ionized hydrogen
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A solar flare is
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an explosion on the solar surface
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How many times bigger is a red giants radius than the suns?
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a red giant's radius may be tens to hundreds of times the radius of the Sun
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What is equivalent to brightness?
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apparent magnitude
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Energy is transferred from the solar core to the bottom of the convection zone by
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radiation
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Solar granulation is an indication that
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energy is transported out of the Sun by convection
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Approximately what fraction of stars within our local neighborhood are main sequence stars?
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90 %
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What is the approximate density of atoms in the interstellar medium?
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1 atom/cm3
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The radial motion of a star is determined by
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the Doppler shift of its absorption lines
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Which of the following four spectral classifications represents the hottest stellar surface temperature of these four? a. A b. B c. G d. K
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a. A --> b. B c. G d. K
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Which of the following four spectral classifications represents the coolest stellar surface temperature of these four? a. B b. K c. A d. G
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a. B --> b. K c. A d. G
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The visible corona of the Sun is most effectively photographed during which eclipse?
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during solar eclipses
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What is the equivalent to luminosity?
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absolute magnitude
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What is the luminosity class of the Sun?
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V
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Stars on the main sequence generate energy how?
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generate energy by thermonuclear fusion in their cores
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What is the approximate expected main sequence lifetime of a star with a mass of 15 solar masses?
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about 15 million years
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The more massive the star the faster or slower the evolution?
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the more massive the original star, the faster the evolution
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Which of the following is NOT the effect of interstellar dust on starlight? a. mutation b. extinction c. reddening d. polarization
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--> a. mutation b. extinction c. reddening d. polarization
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The age of the Sun is about
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5,000,000,000 years
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The luminosity of a star is a unique measure of its
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total energy output
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In the spectral sequence of star types, in which each spectral class has been divided into 10 intervals, the Sun is classified as
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G 2
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what is the order of star spectral classes from hottest to coolest
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O B A F G K M
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We understand that stars above the main sequence of the H-R diagram are the stars that have _____
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stars with larger surface areas
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The brightest star in the night sky is:
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Sirius
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What proportion of visible stars in the nighttime sky are multiple-star systems, such as double stars?
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most stars
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The relationship between mass and luminosity of stars on the Main Sequence is that...
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the greater the stellar mass, the larger the luminosity
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The Sun's source of energy at the present time is
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thermonuclear fusion (combination) of hydrogen atoms
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The evolution of a star depends predominantly upon
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its initial mass
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The surface temperature of a B type star is about
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20,000 K
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Giant magnetic bubbles of ionized gas that separate from the Suns atmosphere and escape into interplanetary space are called
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coronal mass ejections
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The surface temperature of a red star is about
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3000 K
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A reflection nebula is what color?
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is bluish in color
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Compared to an excellent, research quality vacuum on Earth, the density of gas in the interstellar medium is
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the interstellar medium is much less dense.
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The chemical composition of the surface layers of the Sun is determined primarily by what technique?
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spectroscopy
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One particular feature of the solar corona is it is high or low temp?
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its very high temperature
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The brightest stars in the sky were labeled by the Greeks as
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magnitude 1 stars
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Star A is magnitude 3 and Star B is magnitude 8 how many times brighter is star A than star B
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Star A is 100 times brighter than Star B
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The temperature of the core of the Sun, where thermonuclear processes can take place, is approximately
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1.5 x 107 K
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The average time taken for energy generated by thermonuclear fusion in the center of the Sun to reach the surface layers and escape is calculated to be
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tens or hundreds of thousands of years
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The Sun has been stable for a very long time, in hydrostatic equilibrium. Which two parameters must be in balance within the Sun?
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the force of gravity and outward gas pressure
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The Horsehead Nebula is what kind of nebula
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an absorption nebula
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What processes of heat energy transfer are important within the Sun?
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radiation and convection
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The total time that the Sun will spend as a main sequence star is
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about 10 billion years (1010 years)
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The most common molecule in a molecular cloud is
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molecular hydrogen, H2
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On the Hertzsprung-Russell diagram which type of star has the following characteristics: A star with surface temperature 10,000 K, and luminosity 1/100 times that of the Sun.
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white dwarf
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Which main-sequence stars of the spectral classes have the greatest mass?
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O
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Which of the following regions would be hottest? a. Death Valley b. HI regions c. HII regions d. molecular clouds
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a. Death Valley b. HI regions --> c. HII regions d. molecular clouds
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An eclipsing binary system is what?
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two stars which periodically eclipse each other, as seen from Earth
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Binary stars, mutually bound to each other by gravitational forces, allow us to derive which important stellar parameter of the stars?
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stellar mass
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To determine the Sun's luminosity, we must know
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the distance from the earth to the Sun
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Spectroscopic parallax is used to
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determine the distance to main-sequence stars
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Which of the following main sequence stars would have the coolest surface? a. Spectral Class A b. Spectral Class M c. Spectral Class O d. Spectral Class T
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a. Spectral Class A --> b. Spectral Class M c. Spectral Class O d. Spectral Class T
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What is HII?
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ionized hydrogen
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What nebula is an absorption nebula?
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The Horsehead Nebula
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The distance from the Earth to the Sun is
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150,000,000 kilometers
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A coronal hole is
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a hole in the Sun's corona
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A good example of a reflection nebula is
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The Pleiades
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The 21-cm line comes from
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spin-flip of the electron in hydrogen
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How does the temperature of a Sunspot compare to the temperature of the solar surface?
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colder in both hemispheres
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The solar constant is
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1400 Watts/m2
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Differential rotation of the Sun refers to
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the rapid speed of the rotation of the equator of the Sun
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Which of the following spectral classes of stars has the longest main-sequence lifetime? a. A b. B c. F d. G
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a. A b. B c. F --> d. G
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Which of the following spectral classes of stars has the longest main-sequence lifetime? a. K b. M c. O d. Q
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a. K --> b. M c. O d. Q
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The radius of a main sequence star can be determined from
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Luminosity and surface temperature
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A star's luminosity class is determined from
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the width of its absorption lines
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A good example of an absorption (or dark) nebula is
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The Horsehead Nebula
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The distinctive color of a reflection nebula is
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blue, caused by the scattering of light from dust grains
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What is the approximate ratio of hydrogen to helium in the interstellar medium, by number of atoms?
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10 to 1
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The rotation period of the Solar equator is
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25 days
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list the following from smallest radius to largest: red giant, white dwarf, sun
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white dwarf, Sun, red giant
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The oldest star clusters are
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globular clusters
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The interstellar medium is mostly composed of
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diffuse gas composed of hydrogen and helium
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The surface temperature of a red giant is likely to be about
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4,500 K
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The surface temperature of a white dwarf is likely to be about
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10,000 K
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When a neutrino from the Sun reaches the Earth, what is the most likely outcome?
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it passes right through the Earth, unchanged
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Which of the following are NOT main-sequence stars a. white dwarfs b. red giants c. red supergiants d. all of the above
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a. white dwarfs b. red giants c. red supergiants ---> d. all of the above
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For what purpose did Charles Messier construct his catalog of objects?
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To assist his search for comets
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A good example of an emission nebula is
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The Orion Nebula
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Which of the following regions would be coldest? a. HI regions b. HII regions c. molecular clouds d. my dorm room
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a. HI regions b. HII regions --> c. molecular clouds d. my dorm room
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The effective reaction for the proton-proton chain is
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4(H) --> He + neutrinos + energy
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Write an equation relating luminosity, radius, and surface temperature of a star.
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Luminosity ∼ Radius2 x Temperature4
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What is the second most abundant element in the Sun?
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Helium
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Name a star in the constellation Orion that is large enough to be having its size resolved directly.
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Betelguese
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How often does the number of Sunspots on the solar surface reach a maximum?
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Every 11 years
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What is the preferential dimming of short-wavelengths by dust in the interstellar medium called?
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Extinction
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What is the energy transfer process that operates in the Sun via mass motion?
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Convection
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What is the Luminosity Class of the main-sequence stars?
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V
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The Nebula around the Pleiades is an example of what type of nebula?
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Reflection Nebula
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Why does the H-R diagram of a globular cluster NOT contain any stars with high luminosity and high temperature on the main sequence?
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these high-mass stars have evolved away from the main sequence
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What is a stellar association?
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loosely bound group of newborn stars
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Approximately what temperature is required in a collapsing protostar to ignite nuclear burning?
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10,000,000 K
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What do many astronomers regard as a triggering mechanism for star formation?
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passage of a shock wave
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What is unusual about the Algol binary?
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The most massive of the two stars is still on the main sequence
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The Sun will never be what kind of star
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a neutron star
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Most of the supernovae seen by astronomers are
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in other galaxies
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Newborn star clusters are often found with
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emission nebulae
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Which development within the deep interior of the Sun will eventually lead to major changes?
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the build-up of helium in the core
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How does a medium mass star evolve, on the H-R diagram, at the end of its main sequence lifetime?
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to higher luminosity and lower surface temperature
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Infrared stars within the Orion Nebula are examples of which stage of stellar evolution?
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protostar and young star
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The most likely site for the manufacture of heavy elements (beyond hydrogen and helium) in the Universe is
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in the deep interiors of stars
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old stars will have more or less heavy elements
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stars with less abundance of heavy elements
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A pulsar is composed mostly of
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neutrons
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Which of the following processes requires the highest temperature to proceed?
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Carbon fusion
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A star that emits a planetary nebula is likely to become what type of star
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become a white dwarf
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The speed of a neutrino is close to
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The speed of light
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How old would a red giant star in the sky today be?
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10,000,000,000 years
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The path drawn on the H-R diagram below represents the change in
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a Sun-like star during the birth of the star
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Where is one most likely to find a white dwarf star?
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Within a globular cluster
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The pre main-sequence path on the H-R diagram of a protostar depends on
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its mass
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During the formation of stars, the collapse of globules heats the interstellar gas to how many kelvins?
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from less than a hundred degrees Kelvin to millions
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The heaviest stars are formed by collapsing clouds faster or slower than the lightest stars?
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faster than the lightest stars
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Stars of about twice the mass of the Sun are formed from the collapse of interstellar clouds in how many years
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about 10,000,000 years
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OB associations are marked by
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new star formation
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What type of star is the smallest?
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neutron star
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ZAMS stands for
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zero-age main sequence
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A brown dwarf is
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a failed star
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When is hydrostatic equilibrium established in a solar mass star?
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when the core of the star reaches 10,000,000 K
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A chain-reaction of star formation can be propagated by
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supernovae explosions
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The energy for the initial increase in the temperature of a collapsing cloud in star formation comes from
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gravitational energy
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The heavy elements you are made of were formed in
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a supernova explosion
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True or false, supernovae occur only in binary star systems.
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false
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The expected aging of two stars in a binary system would normally be: a- the smaller star evolves quicker b- the bigger star evolves quicker?
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b-the most massive star would evolve quickest
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Stars which contribute most to the chemical enrichment of the interstellar medium are stars which are
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more massive than the Sun
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At about what temperature will helium begin to fuse into carbon
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100,000,000 K
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The neutrino is
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an elusive, subatomic particle, having very little mass, and difficult to detect
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The age of a cluster of stars can be judged by
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the turnoff point on the main sequence of its H-R diagram
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Why are instruments that study ultraviolet radiation put into space orbits?
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The Earths atmosphere absorbs ultraviolet radiation.
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How does a typical nova explosion compare with that for a supernova? a. novas almost always occur in binary stars. b. novas involve explosions of the surface layers. c. novas leave behind most of the mass of the star. d. all of the above. e. none of the above.
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a. novas almost always occur in binary stars. b. novas involve explosions of the surface layers. c. novas leave behind most of the mass of the star. ---> d. all of the above. e. none of the above.
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Stellar remnants with masses between 1.4 and 3 solar masses are what type of stars?
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neutron stars
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A planetary nebula is
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ejected gases from a central star
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What is the main product of helium burning in red giant stars?
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carbon nuclei
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A globular cluster is a group of stars
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all very old, and with little of the heavy elements
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A very low mass object (0.01 to 0.08 solar mass) of low luminosity is what kind of star
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a brown dwarf
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Which physical phenomenon keeps a white dwarf star from collapsing?
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electron degeneracy or quantum crowding
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In our galaxy, as time goes on, the abundance of metals
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increases
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A type II supernova is produced when:
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the collapse of a star's iron nucleus causes a shock wave that "blows off" the envelope of the star.
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A white-dwarf is the likely result from which type of the following main-sequence stars?
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K
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What is the closest location for finding material formed in a supernova explosion?
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your own body
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A group of thousands of very old stars with very few heavy elements is
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a globular cluster
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The mass of a neutron star is how many solar masses?
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must be less than 3 solar masses
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The crab nebula is the result of what
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the result of a supernova explosion
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Heavy elements which are mixed into the material from which new generations of stars may be formed primarily come from
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supernovae
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Which of the following properties does the neutrino NOT possess? a. extremely small mass b. travels at the speed of light c. electrical charge equal to that of the electron d. very penetrating through any matter
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a. extremely small mass b. travels at the speed of light --> c. electrical charge equal to that of the electron d. very penetrating through any matter
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Type I supernovae occur in
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binary star systems.
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What is the equation for the triple alpha process?
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He + He + He -> C + energy
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What is the equation for the CNO cycle?
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C + 4 H -> C + He + energy
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What fraction of the mass of a red giant is ejected as a planetary nebula?
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substantial, between 0.25 and 0.6
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What method can provide direct information about the behavior of stars beneath their surfaces?
answer
neutrino astronomy
question
Helium flash refers to
answer
the runaway helium fusion in the core of a low mass red giant star
question
Where in the Universe would you look for a protostar?
answer
in dense dust and gas clouds
question
Which of the following are NOT very young stars or pre-stellar objects a. infra-red emitting stars in gas and dust clouds b. T Tauri stars c. protostars d. red giants
answer
a. infra-red emitting stars in gas and dust clouds b. T Tauri stars c. protostars --> d. red giants
question
How are elements with nuclei heavier than iron produced?
answer
they are produced during supernova explosions
question
A T Tauri star is at what stage of its stellar evolution?
answer
very early stages, just after protostar formation
question
Most of the energy of a supernova explosion is carried away by
answer
neutrinos.
question
Stars are formed from interstellar matter. Why then are stars in globular clusters metal-poor, while stars in open clusters are metal-rich?
answer
because stellar evolution and supernova explosions increase heavy metal concentrations steadily with time
question
A supernova explosion produces what kind of metals?
answer
produces heavy nuclei all the way up to uranium and thorium.
question
The mass limit of 1.4 solar masses is known as
answer
the Chandrasekhar limit
question
What kind of star masses are the oldest?
answer
globular cluster
question
The characteristics of red supergiant stars are
answer
brightness of about 10,000 Suns and a diameter of about Mars orbit
question
What type of star did the Hubble Space Telescope find many examples of in the globular cluster M4?
answer
white dwarfs
question
The one characteristic shared by all white dwarf stars without binary companions is that
answer
they have ceased to generate energy by thermonuclear processes or gravitational contraction, and are cooling down
question
Which type of Supernova would typically occur soonest after the birth of a star?
answer
type II
question
What surface surrounding a binary star system defines the boundaries of gravitational influence of each star?
answer
Roche Lobe
question
On the diagram above, identify region A
answer
red giant stars
question
Identify region B
answer
blue giant stars
question
Identify region C
answer
the main sequence
question
Identify region D
answer
white dwarfs
question
Identify region E
answer
red dwarfs
question
The Crab Nebula is
answer
a supernova remnant
question
A white dwarf star is about the same size as
answer
the Earth
question
By about how much does a star's luminosity increase during a typical supernova explosion?
answer
100,000,000
question
The sun will eventually become
answer
a white dwarf
question
How may Roche Lobes are there in a binary star system?
answer
Two
question
What is the name given to a star-like object that never burned hydrogen?
answer
Brown dwarf
question
What type of star is Sirius B?
answer
White dwarf
question
In what year did that most recent supernova visible to the naked eye appear in the sky?
answer
1987
question
What fraction of the Suns mass is required for a collapsing system to form a star?
answer
0.08 or 8%
question
In what astronomical body in the sky did SN1987A appear?
answer
Large Magellanic Cloud
question
What type of star is often found at the center of a planetary nebula?
answer
White dwarf
question
There is a mass limit for a star in the white dwarf phase, the Chandrasekhar limit, beyond which the star can no longer support itself against its own weight. What is the value of this mass limit, in terms of solar mass?
answer
1.4 Solar Masses
