Review Test Submission

Correct Answer: The circle in the celestial sphere that the Sun traces out over one year.  Question 12 10 out of 10 points As you stand near Lowell and look at the night sky, which of the following will be in the same position several hours later. Selected Answer: The celestial pole Correct Answer: The celestial pole  Question 13 10 out of 10 points Earth orbits 1 AU from the Sun and has a period of 1 year. Jupiter has a period of 11.9 years. How far does it orbit from the Sun? Selected Answer: 5.2 AU Correct Answer: 5.2 AU  Question 14 10 out of 10 points How does the power law y=x 2  appear on a log log plot? Selected Answer: It appears as a straight line. Correct Answer: It appears as a straight line.  Question 15 10 out of 10 points The Schueller Observatory is located at 42.6427◦N latitude, 71.3365◦W longitude. If the Greenwich Sidereal Time is 12:00, what is the Local Sidereal Time (LST) at the Schueller Observatory? Selected Answer: 7.24 Correct Answer: 7.24  Question 16 10 out of 10 points Which of the following is NOT an example of a power law? Selected Answer: y = mx + b

The Earth has a surface gravity of 1 g. The planet Kepler-99b is thought to have a mass of 6 Earth masses and a radius of 2 Earth radii. What is its surface gravity? Selected Answer: 1.5 g Correct Answer: 1.5 g  Question 5 10 out of 10 points Why is the discover of phosphine on Venus important (if it’s true)? Selected Answer: On Earth phosphine is only naturally produced by living organisms. Correct Answer: On Earth phosphine is only naturally produced by living organisms.  Question 6 10 out of 10 points You are on a spaceship leaving Earth. You are watching Earth as the ship pulls away. The angular diameter of the Earth is Selected Answer: getting smaller. Correct Answer: getting smaller.  Question 7 10 out of 10 points You see a planet accelerating away from you. Is there a net force acting on it? Selected Answer: Yes Correct Answer: Yes  Question 8 0 out of 10 points You measure the ratio of the abundance of potassium-40 to argon-40 in a rock sample. You find more argon-40 than potassium-40. The half life of potassium-40 is 1.25 billion years. How long ago did the rock form? Selected Answer: it’s not possible for radioactive decay to result in more argon-40 than potassium- 40. Correct Answer: more than 1.25 billion years  Question 9

A exoplanet orbits the star ε Eri. The force the star exerts on the exoplanet is _______ the force the exoplanet exerts on the star. Selected Answer: the same magnitude as Correct Answer: the same magnitude as  Question 20 10 out of 10 points Which of the following are Ice Giants? Selected Answers: Neptune Uranus Correct Answers: Neptune Uranus

 Question 8 10 out of 10 points One of the latest spacecraft to land on Mars is Perseverance.  Which of the following is Perseverance NOT doing? Selected Answer: Flying back from Mars with the rock samples it has collected. Correct Answer: Flying back from Mars with the rock samples it has collected.  Question 9 10 out of 10 points What is heating Europa’s oceans? Selected Answer: Volcanism due to tides. Correct Answer: Volcanism due to tides.  Question 10 10 out of 10 points In order to get to Mars, Perseverance flew along 1/2 of an orbit with its perihelion at Earth and its aphelion at Mars. Selected Answer: The semi-major axis of this orbit is larger than the semi-major axis of Earth and smaller than the semi-major axis of Mars. Correct Answer: The semi-major axis of this orbit is larger than the semi-major axis of Earth and smaller than the semi-major axis of Mars.  Question 11 0 out of 10 points Is there a liquid on Io’s surface? Selected Answer: (b) No, the surface is solid Correct Answer: Yes, liquid sulfur  Question 12 0 out of 10 points Where are the conditions thought necessary for life found in the solar system (check all that apply)? Selected Answers: the moon Europa's oceans the surface of Venus

Why do we think that there could be life on Enceladus? Selected Answer: There is evidence for a liquid water ocean under the surface of Enceladus. Correct Answer: There is evidence for a liquid water ocean under the surface of Enceladus.  Question 20 10 out of 10 points What is the liquid on the surface of Titan? Selected Answer: Methane and Ethane Correct Answer: Methane and Ethane

Correct Answer: The terrestrial planets form inside of the “snow line” where few icy planetesimals are found.  Question 12 0 out of 10 points How effective are our searches for near Earth asteroids? Selected Answer: They have discovered only a tiny fraction of the known number of near Earth asteroids. Correct Answer: They are over 90% complete and are continuing to find more near Earth asteroids.  Question 13 10 out of 10 points Neptune and Pluto are in a 3:2 orbital resonance.   A 3:2 orbital resonance is when Selected Answer: two objects have orbital periods that different by a factor of exactly 2/3. Correct Answer: two objects have orbital periods that different by a factor of exactly 2/3.  Question 14 0 out of 10 points Could a hazardous asteroid strike the Earth in the next several hundred years? Selected Answer: We have no idea, we’ve only discovered < 25% of the asteroids near the Earth. Correct Answer: It’s possible but unlikely; We’ve discovered > 99% of the asteroids near the Earth and none of them are going to strike the Earth in the next several hundred years.  Question 15 10 out of 10 points Arrokoth is: Selected Answer: a Trans Neptunian Object Correct Answer: a Trans Neptunian Object  Question 16 10 out of 10 points How did the Earth form? Selected Answer: The Earth began forming when dust was pulled into clumps by static electricity.

 Question 6 0 out of 10 points Radial velocity measurements show that some exoplanet is 10 times the mass of the Earth and transit measurements show that it has 2 times the radius of the Earth. What is the density of the planet? Selected Answer: 1.5 times the density of the Earth Correct Answer: 1.25 times the density of the Earth  Question 7 10 out of 10 points The radial velocity method is biased toward detecting: Selected Answer: Large planets close to their host stars Correct Answer: Large planets close to their host stars  Question 8 10 out of 10 points Newly formed planets are ________ older ones. Selected Answer: hotter than Correct Answer: hotter than  Question 9 10 out of 10 points Which of the following are methods for detecting exoplanets (check all that apply? Selected Answers: Occultation method Doppler method Astrometric method Direct imaging Microlensing method Correct Answers: Occultation method Doppler method Astrometric method

Direct imaging Microlensing method  Question 10 10 out of 10 points The habital zone is the region around a star Selected Answer: where the equilibrium temperature is between 0 and 100 C. Correct Answer: where the equilibrium temperature is between 0 and 100 C.  Question 11 0 out of 10 points On Earth, water (H 2 O) freezes at 0 ◦  C, ammonia (NH 3 ) freezes at −77.3 ◦  C, methane (CH 4 ) freezes at −182 ◦  C, and carbon dioxide (CO 2 ) freezes at −78 ◦  C. Which condenses closest to the Sun in the solar nebula? Selected Answer: ammonia (NH 3 ) Correct Answer: water (H 2 O)  Question 12 10 out of 10 points Jupiter has a radius of 0.1R ⊙  (R ⊙  is the radius of the Sun). If a transit of Jupiter were viewed from a distant star, by about what fraction would the Sun appear to dim? Selected Answer: 10 −2 Correct Answer: 10 −2  Question 13 0 out of 10 points Do all planets orbit stars? Selected Answer: Maybe, it’s possible for planets to exist in interstellar space but we’ve never detected them. Correct Answer: No, just like some planets migrate inward, others are ejected from star systems.  Question 14 10 out of 10 points Why does the direct imaging method use a coronagraph? Selected Answer: To block out light from the host star.

Correct Answer: To block out light from the host star.  Question 15 0 out of 10 points The astrometry method of exoplanet detection uses changes in a star’s to find exoplanets. Selected Answer: mass Correct Answer: position  Question 16 10 out of 10 points What is the Drake equation? Selected Answer: A thought experiment to roughly estimate the number of extraterrestrial civilizations in the Universe. Correct Answer: A thought experiment to roughly estimate the number of extraterrestrial civilizations in the Universe.  Question 17 10 out of 10 points A star is seen to accelerate toward and away from Earth as a planet orbits it.  The amount that the star accelerates can be used to find the planet's: Selected Answer: mass. Correct Answer: mass.  Question 18 5 out of 10 points What is the sequence of events that leads to a large exoplanet close to it's host star? Correct Answer Selected Answer 1. An interstellar cloud collapses and starts to form a star. 1. An interstellar cloud collapses and starts to form a star. 2. Gas near a star spins and forms a disk. 2. Gas near a star spins and forms a disk. 3. Static electricity pulls dust together. 3. Static electricity pulls dust together.

4. Planetesimals get large enough for gravity to hold them together. 4. Planetesimals combine together to form planets. 5. Planetesimals combine together to form planets. 5. The planet forming disk causes planets' orbits to decay. 6. The planet forming disk causes planets' orbits to decay. 6. Planetesimals get large enough for gravity to hold them together.  Question 19 10 out of 10 points Do we find equal numbers of exoplanets of all radii?  Why? Selected Answer: No, the radii of exoplanets we find is related to both the actual radii of exoplanets and the biases of detecting that radius planet. Correct Answer: No, the radii of exoplanets we find is related to both the actual radii of exoplanets and the biases of detecting that radius planet.  Question 20 0 out of 10 points How did roasters form? Selected Answer: Roasters formed near the host star from colliding planetesimal. Correct Answer: Roasters formed outside the “snow line” and migrated inward.

Review Test Submission: Quiz 6  Question 1 0 out of 10 points Lithium has 3 protons in its nucleus. How many neutrons does  7 Li have? Selected Answer: [None Given] Correct Answer: 4 Answer range +/- 0 (4 - 4 )  Question 2 0 out of 10 points If a star is accelerated by an orbiting planet to a velocity of 6 m/s. How much is the Hα line at 656.28 nm shifted? (The speed of light is c = 300, 000, 000 m/s) Selected Answer: 6 × 10 −5  nm Correct Answer: 1 × 10 −5  nm  Question 3 10 out of 10 points Aldebaran is red, Rigil Kentaurus is yellow, Rigel is blue. Which is hotter? Selected Answer: Rigel Correct Answer: Rigel  Question 4 10 out of 10 points When an electron drops to a lower orbital ________ is created. Selected Answer: an emission spectrum Correct Answer: an emission spectrum  Question 5 10 out of 10 points A blackbody spectrum emitted by a hot object is ______ than one emitted by a cool object. Selected Answer: brighter and peaks at a shorter wavelength Correct Answer: brighter and peaks at a shorter wavelength  Question 6

0 out of 10 points Light is Selected Answer: [None Given] Correct Answer: both a wave and made of particles (photons).  Question 7 10 out of 10 points Why is the Chandra X-ray observatory located in orbit rather than on Earth? Selected Answer: The Earth's atmosphere absorbs x-rays making it impossible to see them from the ground. Correct Answer: The Earth's atmosphere absorbs x-rays making it impossible to see them from the ground.  Question 8 10 out of 10 points At what temperature does all molecular motion stop? Selected Answer: 0 Kelvin Correct Answer: 0 Kelvin  Question 9 10 out of 10 points You measure the spectrum of a star and find that it peaks at 100 nm.  What is the temperature of the star?  For reference the Sun is about 6,000K and has a peak wavelength at 500 nm. Selected Answer: 30,000 K Correct Answer: 30,000 K  Question 10 10 out of 10 points Sort the following wavebands from lowest frequency to highest. Correct Answer Selected Answer 1. Radio 1. Radio 2. Microwave 2. Microwave

3. Infrared 3. Infrared 4. Visible 4. Visible 5. Ultraviolet 5. Ultraviolet 6. X-ray 6. X-ray 7. Gamma ray 7. Gamma ray  Question 11 0 out of 10 points Solids tend to emit  [a] ; gasses tend to emit  [b] . Selected Answer: Solids tend to emit    line spectra ; gasses tend to emit    continuous spectra . Correct Answer: Solids tend to emit    continuous spectra ; gasses tend to emit    line spectra .  Question 12 10 out of 10 points The surface temperature of the Sun can be measured using ____. Selected Answer: Wein's law Correct Answer: Wein's law  Question 13 10 out of 10 points The Sun has a temperature of about 5000 K and power of 1 L ⊙ .  What is the power of a similarily sized star with a temperature of 2500 K? Selected Answer: 1/16  L ⊙ Correct Answer: 1/16  L ⊙  Question 14 10 out of 10 points Light with a long wavelength has a  [a]  frequency. A spectrum that peaks at a long wavelength comes from material that has a  [b]  temperature. Selected Answer: Light with a long wavelength has a    low  frequency. A spectrum that peaks at a long wavelength comes from material that has a    low  temperature. Correct Answer: Light with a long wavelength has a    low  frequency. A spectrum that peaks at a long wavelength comes from material that has a    low  temperature.  Question 15

10 out of 10 points If an asteroid has a temperature of 100 Kelvin, at what part of the spectrum does it emit most strongly? Selected Answer: Infrared Correct Answer: Infrared  Question 16 10 out of 10 points What do we call the characteristic spectrum of light emitted by a hot object? Selected Answer: a blackbody spectrum Correct Answer: a blackbody spectrum  Question 17 10 out of 10 points An atom has energy levels of -1,-2, -4, -7, and -11. If it starts in the -2 level, which of the following photons can it absorb? Selected Answer: a photon with 1 unit of energy Correct Answer: a photon with 1 unit of energy  Question 18 10 out of 10 points An object moving away from you will appear  _________ than if the object were at rest and the wavelength of the light will appear to be  ________ than it would be object were motionless. Selected Answer: redder; longer Correct Answer: redder; longer  Question 19 10 out of 10 points Consider a radio wave from the transmitter of your favorite radio station, which has just reached the antenna of the radio in your room. Which of the following statements about this radio wave is CORRECT? Selected Answer: its wavelength is much longer than the wavelength of the light you can see Correct Answer: its wavelength is much longer than the wavelength of the light you can see

 Question 20 10 out of 10 points Which star is coolest? Selected Answer: 2 Correct Answer: 2

Review Test Submission: Quiz 7  Question 1 10 out of 10 points From the outermost inward, the layers of the Sun are: Correct Answer Selected Answer 1. corona 1. corona 2. chromosphere 2. chromosphere 3. photosphere 3. photosphere 4. convection zone 4. convection zone 5. radiative zone 5. radiative zone 6. core 6. core  Question 2 10 out of 10 points The Sun is powered by Selected Answer: the fusion of hydrogen in the core of the Sun Correct Answer: the fusion of hydrogen in the core of the Sun  Question 3 10 out of 10 points An interferometer combines light from more than one telescope Selected Answer: to obtain much greater resolving power. Correct Answer: to obtain much greater resolving power.  Question 4 10 out of 10 points The Hubble space telescope observes  [a] . Selected Answer: The Hubble space telescope observes    visible light . Correct Answer: The Hubble space telescope observes    visible light .

 Question 5 10 out of 10 points The largest refracting telescope is the 1 meter telescope at Yerkes Observatory. How much more collection power will the 30 meter telescope have than the Yerkes telescope if they are both operating at the same wavelength? Selected Answer: 900 times Correct Answer: 900 times  Question 6 10 out of 10 points The Schueller Observatory has a 14-inch telescope, what does the number 14 refer to? Selected Answer: the diameter of the primary lens or mirror Correct Answer: the diameter of the primary lens or mirror  Question 7 10 out of 10 points The largest refracting telescope is the 1 meter telescope at Yerkes Observatory. How much more resolving power will the 30 meter telescope have than the Yerkes telescope if they are both operating at the same wavelength? Selected Answer: 30 times Correct Answer: 30 times  Question 8 10 out of 10 points Granulation is a pattern of bright and dark(er) regions in the Sun’s photosphere. The darker lines are caused by  [a]  while the bright areas are caused by  [b] . Selected Answer: Granulation is a pattern of bright and dark(er) regions in the Sun’s photosphere. The darker lines are caused by    cool(er) gas sinking  while the bright areas are caused by    hot gas rising . Correct Answer: Granulation is a pattern of bright and dark(er) regions in the Sun’s photosphere. The darker lines are caused by    cool(er) gas sinking  while the bright areas are caused by    hot gas rising .  Question 9 5 out of 10 points In the outer part of the Sun is energy travels by  [a]  in the inner part of the Sun energy travels by  [b] . . Selected Answer: In the outer part of the Sun is energy travels by    conduction  in the inner part of the Sun energy travels by    radiation . .

Correct Answer: In the outer part of the Sun is energy travels by    convection  in the inner part of the Sun energy travels by    radiation . .  Question 10 10 out of 10 points Sunspots have _______  magnetic fields than the surrounding surface of the Sun and ______. Selected Answer: higher; are cooler than the surrounding surface of the Sun Correct Answer: higher; are cooler than the surrounding surface of the Sun  Question 11 10 out of 10 points A deformable mirror can be used to correct for: Selected Answer: the distortion of an image caused by refraction in the atmosphere. Correct Answer: the distortion of an image caused by refraction in the atmosphere.  Question 12 10 out of 10 points The Sun is powered by Selected Answer: the P-P chain Correct Answer: the P-P chain  Question 13 10 out of 10 points The net effect of one Proton-Proton chain is to convert  [a]  protons into  [b]   4 He nucleus,  [c]  positrons, and  [2]  neutrinos Selected Answer: The net effect of one Proton-Proton chain is to convert    four  protons into    one   4 He nucleus,    two  positrons, and    two  neutrinos Correct Answer: The net effect of one Proton-Proton chain is to convert    four  protons into    one   4 He nucleus,    two  positrons, and    two  neutrinos  Question 14 10 out of 10 points The ALMA observatory observes  [a] . . Selected Answer: The ALMA observatory observes    radio waves . . Correct Answer: The ALMA observatory observes    radio waves . .

 Question 15 10 out of 10 points Why are we interested in neutrinos from the Sun? Selected Answer: Neutrinos can leave the core of the Sun without interacting with the rest of the Sun Correct Answer: Neutrinos can leave the core of the Sun without interacting with the rest of the Sun  Question 16 10 out of 10 points Solar seismology: Selected Answer: uses the motion of the solar surface to deduce the Sun's internal structure. Correct Answer: uses the motion of the solar surface to deduce the Sun's internal structure.  Question 17 10 out of 10 points IXPE is a small satellite designed to: Selected Answer: measure the polarization of x-rays. Correct Answer: measure the polarization of x-rays.  Question 18 10 out of 10 points Refraction occurs because light in glass moves  [a]  it moves in air. Selected Answer: Refraction occurs because light in glass moves    slower than  it moves in air. Correct Answer: Refraction occurs because light in glass moves    slower than  it moves in air.  Question 19 10 out of 10 points The Sun is in hydrostatic equilibrium. This means that ________ balances _________ at every point in the interior. Selected Answer: pressure; the weight of the gas above Correct Answer: pressure; the weight of the gas above  Question 20 10 out of 10 points

The "solar neutrino problem" was resolved when it was realized that: Selected Answer: Neutrinos oscillate and change flavor as they travel. Correct Answer: Neutrinos oscillate and change flavor as they travel. Review Test Submission: Quiz 8  Question 1 0 out of 10 points You measure the star Vega.  You are then journey to another planet twice as far from Vega and measure it again.  Which of the following are true? Selected Answer: The luminosity will be the same for each measurement; The brightness will be two times fainter for the second measurement. Correct Answer: The luminosity will be the same for each measurement; The brightness will be four times fainter for the second measurement.  Question 2 0 out of 10 points The last solar cycle peaked in about 2013. When will the next minimum (after today) occur? Selected Answer: 11 Correct Answer: 2,030 Answer range +/- 3 (2027 - 2033 )  Question 3 10 out of 10 points In order to measure the distances to nearby stars you first need to know: Selected Answer: the distance from the Earth to the Sun. Correct Answer: the distance from the Earth to the Sun.  Question 4 0 out of 10 points Does the solar cycle ever stop? Selected Answer: No, there is no evidence that it ever has.

Correct Answer: Yes, it stopped during the Spörer minimum in the late 15th century.  Question 5 10 out of 10 points The solar cycle is: Selected Answer: the regular variation in the number of sunspots on the surface of the Sun. Correct Answer: the regular variation in the number of sunspots on the surface of the Sun.  Question 6 10 out of 10 points A  [a]  is a bright flash of light caused when a reconnection of the Sun's magnetic field slams gas down onto the surface.  It may be accompanied by a  [b]  which is gas being expelled from the Sun. Selected Answer: A    flare  is a bright flash of light caused when a reconnection of the Sun's magnetic field slams gas down onto the surface.  It may be accompanied by a    CME  which is gas being expelled from the Sun. Correct Answer: A    flare  is a bright flash of light caused when a reconnection of the Sun's magnetic field slams gas down onto the surface.  It may be accompanied by a    CME  which is gas being expelled from the Sun.  Question 7 0 out of 10 points The solar magnetic field changes direction (reverses) with a period of: Selected Answer: 11 years Correct Answer: 22 years  Question 8 10 out of 10 points The inverse square law relates an objects luminosity, distance, and  [a] . Selected Answer: The inverse square law relates an objects luminosity, distance, and    brightness . Correct Answer: The inverse square law relates an objects luminosity, distance, and    brightness .  Question 9 0 out of 10 points By observing a eclipsing binary you can deduce a star's: Selected Answer: mass Correct Answer: radius

 Question 10 10 out of 10 points The star Arcturus has a parallax angle of 88.83 milliarcseconds. How far away is it? Selected Answer: 11.26 parsecs Correct Answer: 11.26 parsecs  Question 11 10 out of 10 points Sunspots have _______  magnetic fields than the surrounding surface of the Sun and ______. Selected Answer: higher; are cooler than the surrounding surface of the Sun Correct Answer: higher; are cooler than the surrounding surface of the Sun  Question 12 10 out of 10 points You can find an object’s radius by measuring its luminosity and  [a] . Selected Answer: You can find an object’s radius by measuring its luminosity and    temperature . Correct Answer: You can find an object’s radius by measuring its luminosity and    temperature .  Question 13 10 out of 10 points What is the Carrington event? Selected Answer: The largest solar storm ever observed. Correct Answer: The largest solar storm ever observed.  Question 14 10 out of 10 points A star’s temperature can be determined by measuring: Selected Answer: the peak wavelength of its spectrum. Correct Answer: the peak wavelength of its spectrum.  Question 15 10 out of 10 points The spectrum of the star Antares peaks at 790 nm. What is its temperature?  For reference, the Sun is 5700 kelvin and has a peak wavelength of about 500 nm.

Selected Answer: 3,600 K Correct Answer: 3,600 K  Question 16 10 out of 10 points You measure the brightness of Vega, a star 8 parsecs away. You then measure a different, identical, star and find that it is 9 times fainter.  How far away is the fainter star? Selected Answer: 24 parsecs Correct Answer: 24 parsecs  Question 17 10 out of 10 points We use a series of methods, called the distance ladder, to find the distance to astronomical objects. One step in the distance ladder is parallax. What does parallax actually measure? Selected Answer: The apparent motion of stars in the sky as the Earth orbits the Sun Correct Answer: The apparent motion of stars in the sky as the Earth orbits the Sun  Question 18 0 out of 10 points How do you measure a star’s mass? Selected Answer: Measure the spectrum of the star and use Wein’s law. Correct Answer: Measure the period and orbital speed of a spectroscopic binary and use Kepler’s third law.  Question 19 10 out of 10 points Which of the following is a unit of distance (check all that apply)? Selected Answers: Parsec Light Year Correct Answers: Parsec Light Year  Question 20 10 out of 10 points

When a solar storm hits the Earth it can cause: Selected Answer: the aurora to brighten and move toward the equator. Correct Answer: the aurora to brighten and move toward the equator.

Review Test Submission: Quiz 9  Question 1 10 out of 10 points If hydrogen is the most common element in the universe, why do we not see the lines of hydrogen in the spectra of the hottest stars? Selected Answer: in the hottest stars, hydrogen atoms are ionized, and so there are no electrons to produce lines in the spectrum Correct Answer: in the hottest stars, hydrogen atoms are ionized, and so there are no electrons to produce lines in the spectrum  Question 2 10 out of 10 points Where on this HR diagram are the giant stars found? Selected Answer: 2 Correct Answer: 2  Question 3 10 out of 10 points The cold dust in the interstellar medium is seen using: Selected Answer: the reddening it creates in the visible and ultraviolet continuum spectra of stars. Correct Answer: the reddening it creates in the visible and ultraviolet continuum spectra of stars.

 Question 4 10 out of 10 points The Sun is a G2V type star. What does the V signify? Selected Answer: The Sun is a dwarf star. Correct Answer: The Sun is a dwarf star.  Question 5 10 out of 10 points Where on this HR diagram are the hottest, most luminous stars found? Selected Answer: 1 Correct Answer: 1  Question 6 0 out of 10 points

Where on this HR diagram are the smallest radius stars found? Selected Answer: 4 Correct Answer: 5  Question 7 10 out of 10 points The net effect of the CNO cycle is to convert  [a]  proton(s) into  [b]   4 He nucleus(es),  [c]  neutrino(s), and  [d]  positron(s). Selected Answer: The net effect of the CNO cycle is to convert    4  proton(s) into    1   4 He nucleus(es),    2  neutrino(s), and    2  positron(s). Correct Answer: The net effect of the CNO cycle is to convert    4  proton(s) into    1   4 He nucleus(es),    2  neutrino(s), and    2  positron(s).  Question 8 10 out of 10 points Sort these stars from hottest to coolest Correct Answer Selected Answer 1. A main sequence O star 1. A main sequence O star 2. A main sequence B star 2. A main sequence B star 3. A main sequence A star 3. A main sequence A star

4. A main sequence F star 4. A main sequence F star 5. A main sequence G star 5. A main sequence G star 6. A main sequence K star 6. A main sequence K star 7. A main sequence M star 7. A main sequence M star  Question 9 10 out of 10 points As a pre main sequence evolves, which direction does it move on the HR diagram? Selected Answer: Down and right Correct Answer: Down and right  Question 10 0 out of 10 points What is the local interstellar cloud? Selected Answer: A region of low extinction surrounding the Sun. Correct Answer: The interstellar cloud surrounding the Sun.  Question 11 0 out of 10 points What is the Local Bubble? Selected Answer: The molecular cloud from which the Sun formed. Correct Answer: The area of low extinction surrounding the Sun.  Question 12 10 out of 10 points Most of the stars near to the Sun are: Selected Answer: less massive than the Sun. Correct Answer: less massive than the Sun.  Question 13 10 out of 10 points

The gas in an HII region is Selected Answer: ionized. Correct Answer: ionized.  Question 14 10 out of 10 points Sort these stars from least massive to most massive. Correct Answer Selected Answer 1. A main sequence M star 1. A main sequence M star 2. A main sequence K star 2. A main sequence K star 3. A main sequence G star 3. A main sequence G star 4. A main sequence F star 4. A main sequence F star 5. A main sequence A star 5. A main sequence A star 6. A main sequence B star 6. A main sequence B star 7. A main sequence O star 7. A main sequence O star  Question 15 6.66666 out of 10 points What (in order) are the steps in star formation? Correct Answer Selected Answer 1. Interstellar cloud 1. Interstellar cloud 2. Dense cloud core 2. Dense cloud core 3. Protostar 3. Protostar 4. T Tauri star 4. T Tauri star 5. Star forming cloud is destroyed 5. Main sequence star

6. Main sequence star 6. Star forming cloud is destroyed  Question 16 7.5 out of 10 points [a]  destroys light as it passes through the interstellar medium,  [b]  redirects it into a new directions.  The combination of the two is called  [c] , which can be measured by using the stars'  [d] . Selected Answer:   extinction  destroys light as it passes through the interstellar medium,    scattering  redirects it into a new directions.  The combination of the two is called    extinction , which can be measured by using the stars'    reddening . Correct Answer:   absorption  destroys light as it passes through the interstellar medium,    scattering  redirects it into a new directions.  The combination of the two is called    extinction , which can be measured by using the stars'    reddening .  Question 17 10 out of 10 points 90% of stars are: Selected Answer: Main sequence stars Correct Answer: Main sequence stars  Question 18 10 out of 10 points We use the term "interstellar matter" to describe: Selected Answer: gas and dust between stars. Correct Answer: gas and dust between stars.  Question 19 0 out of 10 points If we measure both the spectral type of a star and its color, we can calculate its reddening and deduce: Selected Answer: The mass of the star. Correct Answer: The amount of dust in front of the star.  Question 20 10 out of 10 points A star’s spectral type is determined by: Selected Answer: the spectral lines present in its spectrum.

Correct Answer: the spectral lines present in its spectrum.

Review Test Submission: Quiz 10  Question 1 10 out of 10 points The Earth has an surface gravity of 1 g. What is the surface gravity of a white dwarf with a mass of 100,000 M ⊕ ? Selected Answer: 100,000 g Correct Answer: 100,000 g  Question 2 0 out of 10 points As a one solar mass star first leaves the main sequence and evolves into a red giant it is powered by: Selected Answer: The fusion of hydrogen in its core. Correct Answer: The fusion of hydrogen in a shell around its core.  Question 3 10 out of 10 points The stages of evolution of a low mass star (in order) are: Correct Answer Selected Answer 1. Protostar 1. Protostar 2. Main sequence star 2. Main sequence star 3. Red giant 3. Red giant 4. Planetary nebula 4. Planetary nebula  Question 4 10 out of 10 points Match the object with the energy source that powers it. o Question Correct Match Selected Match Low mass star (< 1.3 solar masses) B. P-P chain B. P-P chain High mass star (> 1.3 solar masses) D. CNO cycle D. CNO cycle Yellow giant C. Triple alpha process C. Triple alpha process protostar A. A.

 Question 5 10 out of 10 points As the core of a Sun-like star uses up its fuel and the star evolves off of the main sequence: Selected Answer: It produces more power. Correct Answer: It produces more power.  Question 6 10 out of 10 points What prevents a main sequence star from collapsing? Selected Answer: thermal pressure Correct Answer: thermal pressure  Question 7 10 out of 10 points Why do massive stars explode after they form an iron core? Selected Answer: Iron is the most stable element and thus cannot undergo further fusion to power the star. Correct Answer: Iron is the most stable element and thus cannot undergo further fusion to power the star.  Question 8 10 out of 10 points

Spica is a star labeled near the upper left of this diagram.  What will be the ultimate fate of Spica be? Selected Answer:  It will end as a Supernova. Correct Answer:  It will end as a Supernova.  Question 9 10 out of 10 points As a high mass star runs out of hydrogen fuel, what happens? Selected Answer: It burns helium, followed by carbon, oxygen, silicon, etc. Correct Answer: It burns helium, followed by carbon, oxygen, silicon, etc.  Question 10 10 out of 10 points What do we call the burned out core of a star? Selected Answer: White dwarf Correct Answer: White dwarf  Question 11 10 out of 10 points What powers a White Dwarf? Selected Answer: Heat left over from its formation.

Correct Answer: Heat left over from its formation.  Question 12 10 out of 10 points Over the next 100 million years, what property of the Sun will change the most? Selected Answer: the composition of the core Correct Answer: the composition of the core  Question 13 10 out of 10 points The Sun has an escape velocity of about 600 km/s. What is the escape velocity of a 1M ⊙  white dwarf with a radius of 6000 km = 10 −2  R ⊙ . Selected Answer: 6,000 km/s Correct Answer: 6,000 km/s  Question 14 10 out of 10 points Match the object with the waveband where it emits most strongly: o Question Correct Match Selected Match Cold interstellar cloud D. Radio D. Radio Protostar A. Infrared A. Infrared 1 solar mass main sequence star C. Visible C. Visible newly formed white dwarf B. Ultraviolet B. Ultraviolet  Question 15 10 out of 10 points As stars go from the main sequence to become red giants, which direction do they move on the HR diagram? Selected Answer: up and right Correct Answer: up and right  Question 16

10 out of 10 points The core collapse in a massive star often results in a _____ which _____ hydrogen lines.  Selected Answer: Type II supernove; shows Correct Answer: Type II supernove; shows  Question 17 10 out of 10 points What is the Chandrasekhar limit? Selected Answer: The mass above which a white dwarf will explode as a Type I supernova. Correct Answer: The mass above which a white dwarf will explode as a Type I supernova.  Question 18 10 out of 10 points As a low mass star runs out of fuel, what happens? Selected Answer: It puffs off its outer envelope and forms a planetary nebula. Correct Answer: It puffs off its outer envelope and forms a planetary nebula.  Question 19 10 out of 10 points Where were most of the elements heavier than neon in the solar system created? Selected Answer: all of these answers Correct Answer: all of these answers  Question 20 10 out of 10 points The result of a white dwarf accreting enough mass to exceed the Chandrasekhar limit is a Type Ia supernova.  This happens when the: Selected Answer: degeneracy pressure cannot support the mass of the star. Correct Answer: degeneracy pressure cannot support the mass of the star. Review Test Submission: Quiz 11  Question 1 10 out of 10 points

How do we know that there is dark matter in the Milky Way? Selected Answer: The Milky Way’s rotation curve is flat. Correct Answer: The Milky Way’s rotation curve is flat.  Question 2 10 out of 10 points A one solar mass black hole has an Schwartzchild radius of 3 km. What is the Schwartzchild radius of a 21 solar mass black hole? Selected Answer: 63 km Correct Answer: 63 km  Question 3 10 out of 10 points What is the Milky Way’s rotation curve? Selected Answer: The relationship between the speed that stars are moving and their position. Correct Answer: The relationship between the speed that stars are moving and their position.  Question 4 10 out of 10 points What is a cluster’s main sequence point? Selected Answer: The point on a cluster’s HR diagram where you find the most massive star not yet evolved off the main sequence. Correct Answer: The point on a cluster’s HR diagram where you find the most massive star not yet evolved off the main sequence.  Question 5 10 out of 10 points What can be deduced by measuring a cluster’s main sequence turn off? Selected Answer: The cluster’s age Correct Answer: The cluster’s age  Question 6 5 out of 10 points

Sort the following from lowest mass-to-light ratio to highest. Correct Answer Selected Answer 1. main sequence O star 1. main sequence O star 2. main sequence G star 2. main sequence G star 3. main sequence M star 3. Milky Way 4. Milky Way 4. main sequence M star  Question 7 10 out of 10 points The region around a black hole where everything is trapped, and nothing can get out to interact with the rest of the universe, is called Selected Answer: the event horizon Correct Answer: the event horizon  Question 8 0 out of 10 points What is the escape velocity from just outside of the event horizon of a black hole. Selected Answer: more than the speed of light. Correct Answer: just less than the speed of light.  Question 9 10 out of 10 points Which of the following can escape from inside the event horizon of a black hole? Selected Answer: None of the above Correct Answer: None of the above  Question 10 10 out of 10 points Once a black hole forms, the size of its event horizon is determined only by Selected Answer: the mass inside the event horizon

Correct Answer: the mass inside the event horizon  Question 11 10 out of 10 points Sort these from largest radius to smallest radius. Correct Answer Selected Answer 1. red dwarf 1. red dwarf 2. white dwarf 2. white dwarf 3. neutron star 3. neutron star 4. 1 solar mass black hole 4. 1 solar mass black hole  Question 12 10 out of 10 points How far are the nearest stars away from the Sun? Selected Answer: a few parsecs Correct Answer: a few parsecs  Question 13 10 out of 10 points Black holes emit x-rays. How do the x-rays escape the black hole? Selected Answer: The light is emitted by gas above the event horizon. Correct Answer: The light is emitted by gas above the event horizon.  Question 14 10 out of 10 points The parts of the Milky Way from largest size (radius) to smallest are: Correct Answer Selected Answer 1. halo 1. halo 2. disk 2. disk

3. bulge 3. bulge  Question 15 10 out of 10 points What is the Milky Way's initial mass function? Selected Answer: The curve showing how many stars form as a function of mass. Correct Answer: The curve showing how many stars form as a function of mass.  Question 16 0 out of 10 points How do you find the age of the Milky Way? Selected Answer: By using the Milky Ways main sequence turn off Correct Answer: By comparing the present day mass function (PDMF) to the initial mass functoin (IMF)  Question 17 10 out of 10 points Is the Milky Way galaxy still gaining matter? Selected Answer: Yes, for instance, the Andromeda galaxy will impact the Milky Way and begin to merge in about 5 billion years. Correct Answer: Yes, for instance, the Andromeda galaxy will impact the Milky Way and begin to merge in about 5 billion years.  Question 18 10 out of 10 points Open clusters are generally Pop I stars and globular clusters are always Pop II.  From this we can conclude that: Selected Answer: Globular clusters are older while open clusters are younger. Correct Answer: Globular clusters are older while open clusters are younger.  Question 19 10 out of 10 points LIGO has measured which of the following? Selected Answer: neutron star – neutron star mergers

Correct Answer: neutron star – neutron star mergers  Question 20 0 out of 10 points Population II stars are Selected Answer: young, red, and high in heavy elements Correct Answer: old, red, and low in heavy elements

Review Test Submission: Quiz 12  Question 1 10 out of 10 points The Center for Astrophysics Redshift Survey (CFA1) recorded the positions and redshifts of galaxies up to z = 0.03. What is the distance to an object with z = 0.03? Selected Answer: 130 Mpc Correct Answer: 130 Mpc  Question 2 10 out of 10 points You find a Cepheid variable in a galaxy 10 Mpc away with a bright-dim-bright period of 35 days. You find a second galaxy with a Cepheid variable with the same period but it appears to be 25 times fainter. How far away is the second galaxy? Selected Answer: 50 Mpc Correct Answer: 50 Mpc  Question 3 10 out of 10 points Which of the following is NOT a type of galaxy? Selected Answer: giant toroidal. Correct Answer: giant toroidal.  Question 4 10 out of 10 points What two properties of a galaxy does the Hubble Law relate? Selected Answer: distance and radial velocity. Correct Answer: distance and radial velocity.  Question 5 10 out of 10 points Which of the following is evidence for dark matter? Selected Answer: Galaxies in clusters are moving faster than would be expected without dark matter. Correct Answer: Galaxies in clusters are moving faster than would be expected without dark matter.

 Question 6 0 out of 10 points If you know the apparent brightness and distance to a Cepheid variable you can use the _______ to find its ________. Selected Answer: inverse square law; velocity Correct Answer: inverse square law; luminosity  Question 7 10 out of 10 points Elliptical galaxies tend to be ______ and contain ______ gas and dust. Selected Answer: red; very little Correct Answer: red; very little  Question 8 10 out of 10 points Cepheid variables are located in two different galaxies, A and B.  Both stars have the same average apparent  magnitude.  The star in galaxy A has a bright-dim-bright period of 10 days.  The star in galaxy B has a bright-dim-bright period of 30 days.  Which of the two galaxies is at a greater distance?  Selected Answer: B Correct Answer: B  Question 9 10 out of 10 points What is this a picture of:

Selected Answer: Disk galaxy Correct Answer: Disk galaxy  Question 10 0 out of 10 points How large is the Universe? Selected Answer: It's impossible to tell. Correct Answer: It's a sphere 13.7 billion light years in radius.  Question 11 10 out of 10 points The velocity with which a galaxy recedes from us is proportional to _____ . Selected Answer: its distance Correct Answer: its distance  Question 12 10 out of 10 points Match the description with the galaxy type. o Question Correct Match Selected Match Spiral galaxy with a large bulge, and arms tightly wound C. Sa C. Sa Spiral galaxy with a very small bulge, and arms very loosely wound. A. Sd A. Sd Elliptical with no flattening B. E0 B. E0 An elliptical galaxy which is very flattened. D. E7 D. E7  Question 13 10 out of 10 points The Hubble constant is about 70 km/s/Mpc.    You measure the redshift of four galaxies.   The first has a redshift of 1500 km/s, the second has a redshift of 7500 km/s, the third has a redshift of 5000 km/s and the fourth has a redshift of 2000 km/s.  Which galaxy is the closest? Selected Answer: The galaxy with a redshift of 1500 km/s

Correct Answer: The galaxy with a redshift of 1500 km/s  Question 14 10 out of 10 points What is Olber's paradox? Selected Answer: Why is the sky dark at night? Correct Answer: Why is the sky dark at night?  Question 15 10 out of 10 points You find a galaxy with a recession velocity of 14,000 km/s. How far away is it? Selected Answer: 200 Mpc Correct Answer: 200 Mpc  Question 16 10 out of 10 points We measure that the Hubble constant is about 70 km/s/Mpc and deduce that the Universe is 13.7 Gyr old. If the Hubble constant were 280 km/s/Mpc what would we deduce the age to be? Selected Answer: 3.425 Gyr Correct Answer: 3.425 Gyr  Question 17 10 out of 10 points You find a type Ia supernova in a galaxy known to be 12 Mpc away.  Later you find another type Ia supernova in a second galaxy. If the first supernova is 9 times brighter than the second, how far away is the second galaxy? Selected Answer: 36 Mpc Correct Answer: 36 Mpc  Question 18 10 out of 10 points Type Ia supernovæ can be used to find the distance to a galaxy using Selected Answer: the inverse square law

Correct Answer: the inverse square law  Question 19 10 out of 10 points Match the object with the method of determining its distance? o Question Correct Match Selected Match Distant galaxy B. Measure its redshift and use Hubble’s law. B. Measure its redshift and use Hubble’s law. Nearby galaxy A. Use Cepheid variables and the period-luminosity relationship. A. Use Cepheid variables and the period-luminosity relationship. Stars in the Milky Way D. Use parallax. D. Use parallax. Planets C. Use radar. C. Use radar.  Question 20 10 out of 10 points Listed from most elongated to most circular the sequence of elliptical galaxies is: Selected Answer: E7 to E0 Correct Answer: E7 to E0