it is practical to build larger reflecting telescopes. 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. A globular cluster is a group of stars that are what? Supernovae occur in stars with at least 8 solar masses. What is the one fundamental difference between x-rays and radio waves? Why does the H-R diagram of a globular cluster NOT contain any stars with high luminosity and high temperature on the main sequence? Supernovae death reveals link to stars' birth. A star whose surface temperature is 100,000 K will emit a spectrum whose peak wavelength is. These organisms are collectively called: the average survival time of the civilizations. What makes the subject of the star formation so difficult and complex? What special event was observed in the Large Magellanic Cloud in 1987? The resolution of a typical radio astronomy telescope for 1 meter wavelength is about. Astronomy from space vehicles is particularly useful because? T/F A star of the sun's diameter, but twice as hot, must be 16x more luminous than the sun, T/F the Proper motion of a star is its true velocity through space. Any ultra-massive star that loses enough of the "stuff" that makes it up can easily go supernova if the overall star structure suddenly falls into the right mass range. Given that a 6000 K surface emits radiation ("blackbody theory") with a peak wavelength of 0.48 microns? to higher luminosity and lower surface temperature. The relationship between energy (E) and the frequency of a photon (f) is? Shapley measured the distances to globular clusters by using. Stellar remnants with masses between 1.4 and 3 solar masses will be? True or False? At this stage, the star will appear: b)faster and at a higher luminosity and temperature. Hydrostatic equilibrium in our sun is the balance between: The light we see from the sun comes from which layer? Star C appears brighter in the blue than in the red. On the absolute Kelvin temperature scale, the temperature of freezing water is about? d)O and B blue giants are much brighter than G, K, or M dwarfs. Write. 2 is close, but implies that any star can go supernova, which is not true. Ripples in the Cosmic Microwave Background correspond to: chemical evolution has taken place elsewhere in the Universe. The closest star to Earth is our very own Sun, so we have an example nearby that astronomers can study in detail. first supernova visible on Earth to the naked eye in 400 years. The best evidence for supermassive black holes in the centers of galaxies is, A neutron star's immense gravitational attraction is due primarily to its small radius and, Most of the bright stars in our Galaxy are located in the Galactic. What effect do even thin clouds of dust have on light passing through them? gamma-rays, X-rays, ultraviolet radiation. Compared to other stars on the H-R diagram, red-giant stars are so named because they are: After the core of a sun-like star starts to fuse helium on the horizontal branch, the core becomes, compared to the sun, stars plotted near the bottom left on the H-R diagram are much, The percentage (by mass) of the sun that is hydrogen is about, The critical temperature the core must reach for a star to shine by fusion is. b)they both involve high mass ionizing stars. Also, if we had been born in a crowded (dense) globular cluster, all the stars in the cluster would still be around us and with us. The light-gathering power of a telescope is related directly to? A star can be a supernova: A) in predictable cycles of decades. The lessons we learn about the Sun can be applied to other stars. The energy for the initial increase in the temperature of a collapsing cloud in star formation comes from? What is the brightest star in the evening sky? The object will look shorter than if it were at rest. Calculate the distance of one light year in kilometers, beginning from the speed of, 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. d)inflate rapidly early in its existence. only specific wavelengths of light ("absorption lines") will be removed from the spectrum, a small, massive, electrically charged core ("nucleus") with electrons surrounding it. The Earth's turbulent atmosphere will smear point like images of stars into "seeing disks? Rotation curves for spiral galaxies show: e)a larger and larger percentage of the matter is dark. Beyond the formation of iron, nuclear energy can be produced only by: The element with the most stable nucleus and smallest mass per particle is: At temperatures of ________ K, photons can split apart nuclei until only protons and neutrons are left in photodisintegration. We understand that stars above the main sequence of the H-R diagram are the result of: What proportion of visible stars in the nighttime sky are multiple-star systems, such as double stars? Put another way, a star explodes … QUESTION 7: The mass of a star can be determined by: a) Measuring its luminosity b) Determining its composition. e)It is a large sheet of galaxies measuring 70 Mpc by 200 Mpc. If it appears to move back and forth relative to other stars over a six-month period, this motion is due to the star's: The Hertzsprung-Russel Diagram plots _________ against the spectral type or temperature. d) helium builds up in the core, while the hydrogen burning shell expands. Browse. e)galaxies farther away are moving away from us faster. determine the distance to main-sequence stars. the runaway helium fusion in the core of a low mass red giant star. Which is NOT the effect of interstellar dust on starlight? Assuming the conditions ripe for life and intelligence abound in the Galaxy, what factor limits the number of galactic civilizations? Why then are stars in globular clusters metal-poor, while stars in open clusters are metal-rich? What is the energy transfer process that operates in the Sun via mass motion? The most common molecule in a molecular cloud is. A "fuzzy" dark or light patch in the sky is called a: What is the force that keeps a main sequence star from blowing apart? This cycle of contraction, heating, and the ignition of another nuclear fuel r… During this process the core of the Star turns to iron and the Star will become unstable. The silver atoms found in jewelry originated in, A massive star becomes a supernova when it, An observable supernova should occur in our Galaxy about once every. The redshift of the universe at decoupling was about: The best answer to both the flatness and horizon problems is: The horizon problem, in that the microwave background is almost too isotropic. Which is the correct description of the Sun's location within the Milky Way? 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? The Earth's atmosphere absorbs ultraviolet radiation. The core heats to billions of degrees and explodes (supernova), thereby releasing large amounts of energy and material into space. Which development within the deep interior of the Sun will eventually lead to major changes? change from the infrared to the visible wavelengths. The two windows of the atmosphere are? This probably indicates that: Collisions between galaxies are thought to: c)cause the gas and dust clouds to collide, leading to rapid star formation. What is a Type Ia Supernova? A white-dwarf is the likely result from which type of the following main-sequence stars? Which of the following types of telescope will suffer from chromatic aberration unless expensive measures are taken to avoid it? Which type of Supernova would typically occur soonest after the birth of a star? a)the temperature is almost exactly the same everywhere. How does a medium mass star evolve, on the H-R diagram, at the end of its main sequence lifetime? Which star(s) are NOT very young stars or pre-stellar objects? Compared to an excellent, research quality vacuum on Earth, the density of gas in the interstellar medium is? The best shape for the cross-section of a large astronomical mirror in order to produce the sharpest images of very distant objects is? c)The greater the distance to a galaxy, the greater its redshift. The surface temperature of a B type star is about? Every line appears at a slightly longer wavelength, shifted towards the red end of the spectrum. Which of the following main sequence stars would have the coolest surface? Stars which contribute most to the chemical enrichment of the interstellar medium are stars which are? Create. they each produce different specific emission line wavelengths. Gravity. What is the main reason for combining many radio telescopes together into an interferometer with large distances between telescopes? What is the key factor that determines the temperature, density, radius, luminosity and pace of evolution of a protostellar object? The temperature of a star can be inferred from? mass . which of these orderings of the epochs is correct? Which of the following is NOT an argument for Cygnus X-1's being a true black hole? Chromatic aberration occurs in a telescope when? If 2.00 kg of mass is converted to energy, how much energy will be produced? Which of the following types of the electromagnetic radiation could provide the best resolution in the same size instrument? Binary stars, mutually bound to each other by gravitational forces, allow us to derive which important stellar parameter? The effective reaction for the proton-proton chain is? On the basis of our current best estimate of the present mass density of the universe, astronomers think that, Immediately after its birth, the universe, Present-day Grand Unified Theories unite all of the fundamental forces except. the collapse of a star's iron nucleus causes a shock wave that "blows off" the envelope of the star. Radio waves travel through space at what speed? Which of the following paraphrases Hubble Law? the optical window and the radio window. The heaviest stars are formed by collapsing clouds? *****Neutron stars In a massive star that collapses and explodes as a supernova, a neutron star is often left behind. Which of the following regions would be hottest? e)The RR Lyrae stars have much shorter periods than Cepheids. Of all the chemical elements, the one most crucial to the complexity of life is. Which of the following terms is equivalent to brightness? energy is transported out of the Sun by convection. Which of these technological advances would make it harder for extraterrestrial life to find us? blue, caused by the scattering of light from dust grains. Probably the correct answer is 4, since any star massive enough to fuse to iron can go supernova. A photon of wavelength 10 micro-meters is considered? A high-mass star dies more violently than a low-mass star because: As a 4-10 solar mass star leaves the main sequence on its way to becoming a red supergiant, its luminosity: What characteristic of a star cluster is used to determine its age? 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? The radius of a main sequence star can be determined from? supernovae occur only in binary star systems. The nuclear epoch occurred during the formation of: At the end of the first fifteen minutes, the mass ratio of H/He created was about: a)Expansion cooled the universe enough that protons could capture electrons in orbit. b)look for their effects on nearby companions. How often does the number of Sunspots on the solar surface reach a maximum? b)it was experimental verification of a prediction from the Big Bang theory. A fragment of a collapsing gas cloud that comes to equilibrium with a central temperature of 4 million K will become a: c)fusion of hydrogen atoms into helium atoms, b)from the release of gravitational energy as the protostar continues to shrink. From inside out, which is in the correct order for the structure of the sun? The most massive of the two stars is still on the main sequence. Is this star still there? b)we see the galaxy the way it was one billion years ago. the turnoff point on the main sequence of its H-R diagram. Roughly 1.4 solar masses within a radius of 10 kilometers! the average survival time of civilizations. What is the name given to a star-like object that never burned hydrogen? The Tully-Fisher relation exists between the galaxy's luminosity and its: e)Cepheids are too faint to be seen beyond that distance, even with HST. What conclusion can be drawn from this observation? Suppose the spectrum of a solar-type star shows an equivalent set of dark absorption lines, but with one exception. The rotation period of the Solar equator is? The mass limit of 1.4 solar masses is known as? d)passages of spiral density waves through the interstellar medium. This indicates: a)it generates more heat and its core eventually collapses very suddenly. surface temperature . two electrons and a nucleus of two protons and two neutrons. Which statement below is correct? Why is the hypothesis that like on earth came form outer space considered plausible? The radial motion of a star is determined by? What explanation does general relatively provide for gravity? According tot he standard model of the sun, as the distance from the centre increases, the density decreases: A typical solar granule is about the size of, As we move to greater and greater distances above the solar photosphere, the temperature in the sun's atmosphere, The time between successive sunspot maxima is about, fusion of light nuclei to make heavier ones, The primary source of the sun's energy is, we detect more solar neutrinos than we expect, Compared with Earth;s diameter, the sun's diameter is about, The sun spins on its axis roughly once each, From a distance of 1 parsec, the angular size of Earth;s orbit would be, According to the inverse-square law, if the distance to a lightbulb increases by a factor of 5, the bulb's apparent brightness, compared wit a star of absolute magnitude -2 at a distance of 100pc, a star of absolute magnitude a distance of 10 pc will appear, their surfaces are so cool that most hydrogen is in the ground state, Stars of spectral class M do not show strong lines of hydrogen in their spectra because, cool stars can be very luminous if they are very, by studying its orbit around a binary companion, Pluto's apparent magnitude is approximately 14. the rapid speed of the rotation of the equator of the Sun. Rank these stars in order of increasing surface temperature. Which of the following four spectral classifications represents the hottest stellar surface temperature of these four? Created by. A supernova is the explosion of a star -- the largest explosion that takes place in space. In globular clusters, the brightest stars will be: Mass transfer in binaries occurs when one giant swells to reach the: A surface explosion on a white dwarf, caused by falling matter from the atmosphere of its binary companion, creates what kind of object? What is the approximate density of dust in the interstellar medium? The interstellar medium is mostly composed of? d)more than 25 times the mass of the Sun. If the density of the universe is at the critical density, this means that: a)ordinary matter, dark matter, neutrinos, gravity waves, electromagnetic energy and dark energy. On average, a supernova will occur about once every 50 years in a galaxy the size of the Milky Way. What important molecules of life did Miller and Urey brew up? Hans Bethe and other physicists explained the source of the Sun's energy as? The total time that the Sun will spend as a main sequence star is? What happens when a beam of white light (containing all colors) is passed through a prism of glass? Why does the cepheid "standard candle" have limited usefulness beyond 20 Mpc? A red supergiant is observed in a globular cluster in another galaxy (located 150,000 light years away). Which one of the following does not provide evidence that supernovae have occurred in our Galaxy? What temperature is needed to fuse helium into carbon? the Earth's atmosphere is transparent to visible light, The best wavelength for penetrating dusty regions of interstellar space, and detecting otherwise hidden objects is. How does the temperature of a Sunspot compare to the temperature of the solar surface? Higher mass protostars enter the main sequence: a) the rate of nuclear energy generated in the hydrogen to helium fusing core equals the rate radiated from the surface. It is predicted, based on its mass and age of the star that it will supernova in about 10,000 years. What method can provide direct information about the behavior of stars beneath their surfaces? Compared with slowly rotating stars, the fastest spinning stars have absorption lines that are? What type of radiation has wavelengths in the range of 0.7 microns to 100 microns? Which relationship concerning the mass of protostars is FALSE? Due to absorption of shorter wavelengths by interstellar duct clouds, distant stars appear: Emission nebulae like M42 occur only near stars that emit large amounts of: c)stars in that region are hidden by sark dust particles. the interstellar medium is much less dense. thermonuclear fusion (combination) of hydrogen atoms. Which of the following terms is equivalent to luminosity? a 12000 K surface has a peak at 0.24 microns. Stars of about twice the mass of the Sun are formed from the collapse of interstellar clouds in how long? Medium-large stars supernova, with medium stars forming a neutron star at the end, and large ones forming a black hole. What would happen if mass is added to a 1.4 solar mass white dwarf? sometimes as a wave, and sometimes as a particle, The distance to the closest star beyond the Sun is about, the distance which has a 1 arcsecond parallax. When new particle pairs are being created as fast as they annihilate, it is: b)dark matter not made of protons and neutrons. How long to carry away the total mass of the sun? Different elements can be distinguished by their emission spectrum in that? Where he expected to see only faint stars, he saw a large bright spot. d)if the beam sweeps across us, we will detect a pulse of radiation. list the types of stars from smallest radius to largest? explosive nucleosynthesis during supernova explosions of massive stars. d)greater than the age of the Milky Way Galaxy. Which of the following regions would be coldest? b)made of compressed neutrons in contact with each other. As the star runs out of nuclear fuel, some of its mass flows into its core. What is the approximate density of atoms in the interstellar medium? the region around each star where terrestrial planets could have liquid water on their surfaces, because many meteorites contain complex organic molecules. The most important fact about a cluster of stars that makes them useful for studying star formation is that, e)old age and hundreds of thousands to millions of member stars. ALL OF THE ABOVE Parallax can be used to determine star distances for? Which of the following is true? For decades, scientists have suspected a star explosion called a supernova helped trigger our solar system's formation. The evolution of a star depends predominantly upon? these high-mass stars have evolved away from the main sequence. some regions along the plane of the milky way appear sark because : What is the primary visible color of an emission nebula? The Doppler Effect is the change in the wavelength of light caused by what source? What color of visible light has the shortest wavelength? res = 0.25 x 0.5 / 2.4 arc-sec = 0.05 arc-sec. In understanding stars, the Bohr atom is useful for the following purpose(s): it helps us understand the spectral lines. What fraction of the mass of a red giant is ejected as a planetary nebula? What is the force that keeps a main sequence star from collapsing on itself? Radiative zone, convection zone, chromosphere. Only $1/month. Estimate the "solar Constant" on mercury at Penihilion. d) Close to our solar system. Most of the supernovae seen by astronomers are? What was the first astronomical radio source discovered by Karl Jansky? we lay near the centre of a disk about 10kpc wide and 2kpc thick. What evidence is there that supernovae really have occurred? It is the annual apparent motion of a star across the sky. The Star will continue to become more and more unstable which will cause a nuclear reaction in the core causing the Star to go Supernova. c) Large. Which of the following four spectral classifications represents the coolest stellar surface temperature of these four? What is the nearest huge cluster of galaxies to our Local Group? Where in the Universe would you look for a protostar? when an electron drops from an energy state to a lower energy state. The cosmological principle would be invalidated if we found that, When we use Hubble's law to estimate the age of the universe, the answer we get. E) only once. Just as there are different types of stars, there are different types of supernovae. it passes right through the Earth, unchanged, white dwarfs, red giants & red supergiants. Refracting telescopes are limited because? d. they both involve high mass ionizing stars. What properties does the neutrino NOT possess? The one characteristic shared by all white dwarf stars without binary companions is that? The presently accepted value of the Hubble constant gives an age of: e)because all the light from all the objects in the universe hasn't arrived here yet. e)He relied on visual wavelengths, which are obscured by dust. Type Ia supernova occurs at the end of a single star’s lifetime. Giant magnetic bubbles of ionized gas that separate from the Sun's atmosphere and escape into interplanetary space are called. As we look at larger and larger scales in the universe, we find: a)this is evidence for intergalactic matter. Upgrade to remove ads. 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