condensed astro test 2

1) TorFIf the distance between us and a star is doubled, the apparent brightness is decreased by a factor of four. 2)TorF We can measure stellar parallax for most stars in our galaxy. 3)TorF Spectral type, surface temperature, and color all describe the same basic characteristic of a star. 4) The apparent brightness of a star depends only on its luminosity. 5)TorF The more distant a star, the smaller its parallax. 6)TorF Two stars have the same luminosity. Star X is spectral type F, while Star Y is spectral type K. Therefore, Star X is larger in radius than Star Y. 7) TorF The nearest star to our Sun, Alpha Centauri, is still over a parsec distant. 8)TorF In a spectroscopic binary, the star whose lines shift the most weighs the most. 9)TorF A type B9 star is hotter than a type A0. 10)TorF The proper motion of a star is its true velocity through space. 11)TorF The proper motion of a star, its distance, and Doppler shift can give us its space velocity. 12)TorF First magnitude Spica appears 2.5 times brighter than second magnitude Polaris 13)TorF In a binary system, the more massive stars always stay closer to the center of mass and move slower. 14)TorF A star of the Sun's diameter, but twice as hot, must be 16X more luminous than the Sun. 15)TorF Star A and star B have the same apparent magnitude. Star A is twice as distant as star B. Therefore, star A has twice the luminosity as star B. 16)TorF If a star were moved 10 times farther away, its absolute magnitude would drop five magnitudes. 17) The spectral sequence in order of decreasing temperature is . 18)TorF Which of the following statements about apparent and absolute magnitudes is true? . 19) If Star A is closer to us than Star B, then Star A's parallax angle is 20) The star Vega has an absolute magnitude of about 4 and an apparent magnitude of about 0. Based on the definitions of absolute and apparent magnitude, we can conclude that . 21) Which of the following terms is given to a pair of stars that we can determine are orbiting eachother only by measuring their periodic Doppler shifts? 22) The Hertzsprung-Russell Diagram plots ________ against the spectral type or temperature. 23) A nearby star has a parallax of 0.2 arc seconds. What is its distance? 24) What is proper motion? 25) What physical property of a star does the spectral type measure? 26) On the H-R diagram, the Sun lies . . 27) The Doppler shift of the dark regions is 0.001% the speed of light. If one particular specttral line has a rest wavelength of 480.00 nm, what is the measured wavelength of the same line from the diagram? 28) In comparing first magnitude Deneb with second magnitude Polaris, we find that: . 29) The absolute magnitude of a star is its brightness as seen from a distance of: 30) If a star is found by spectroscopic observations to be about 500 parsecs distant, its parallax is: 31) In the previous question, one star is exhibiting a blue shift, the other is exhibiting a redshift. If the ratio of speeds is 4:1 this imples the ratio of distances from the center of mass is also 4:1. The smaller star is 8 Solar Masses. Determine the period of revolution of the system if the larger star is 20 AU from the center of the system. Below is what such a system may look like . 32) Which statement about stellar motion is incorrect? 33) Star A and star B have the same temperature, but star B is 20 times smaller than star A. Which statement below is correct? 34) If a star appears to move back and forth relative to other stars over a six-month period, this motion is due to the star's 35) Star A is a main sequence star of spectral type F2 and star B is a white dwarf of spectral type B4. Which statement below is correct? . 36) A star has an apparent magnitude of +7 and an absolute magnitude of -4. What is the distance to the star? 37) The star shown is Rigel, from the constellation Orion. If the Earth orbited Rigel at 1AU, it would be seen as a very large blue star with an apparent magnitude of -38!! Rigel actually has an apparent magnitude of +0.2. If the distance to rigel is 772.9 ly (237.1pc), determine the absolute magnitude of Rigel. 38) In a spectroscopic binary system, the star showing the larger blue shift is: 39) Star A and star B both have an apparent magnitude of 4.0, but star A has an absolute magnitude of 1.0 and star B has an absolute magnitude of 7.0. Which statement below is correct? 40) In order to turn a star's proper motion into its space velocity, we must also know: Consider the image below which shows the top of the convective zone (photosphere) of the Sun. The dark regions are red-shifted and a scale is provided for reference. The Doppler shift of the dark regions gives a radial velocity of 300 km/sec. If one particular spectral line has a rest wavelength of 480.00 nm, what is the measured wavelength of the same line from the diagram? 2) Star A and star B both have an apparent magnitude of 2.0, but star A has an absolute magnitude of +3.0 and star B has an absolute magnitude of -5.0. Which statement below is correct? 3) Procyon lies about 13 light-years distant, thus its parallax is about: 4) On a Hertzsprung-Russell diagram, where would you find stars that are hot but not very luminous? 5) Which of the following statements about apparent and absolute magnitudes is true? 6)TorF Energy from the core of the Sun first travels slowly through a convection zone and then much faster through the outer radiation zone. 7) In a spectroscopic binary system, one star shows a large blue shift and the other is showing a small redshift. What conclusion can be drawn from this information? 8) Consider HR diagram ONE on the cover sheet. Find Capella and the Sun. Estimate how many times bigger or smaller Capella is than the Sun 9) A star has an apparent magnitude of +7 and an absolute magnitude of -4. What is the distance to the star? 10) If Star A is closer to us than Star B, then Star A's parallax angle is 11)TorF A star of the Sun's diameter, but five times hotter, must be 625 times more luminous than the Sun. 12) Where in the Sun do fusion reactions happen? 13) The Sun's surface, as we see it with our eyes, is called the . 14) Star A and star B have the same temperature, but star B is 20 times smaller than star A. Which statement below is correct? 15) In the proton-proton cycle, the helium atom and neutrino have less mass than the original hydrogen. What happens to the "lost" mass? 16) An O-star has a hotter surface temperature than the Sun. Therefore, compared to the Sun, 17) The Corona of the Sun is superheated and radiates X Rays with a peak wavelength of 0.2nm. Determine the temperature of this region of the Corona. 18)TorF 1.5 magnitude Sirius appears 25 times brighter than second magnitude Polaris. 19) Each choice below lists a spectral type and luminosity class for a star. Which one is a red supergiant? 20) The diagram shows a binary star system where the mass of the smaller star is 8 Solar masses. If the ratio of speeds is 4:1 this implies the ratio of distances from the center of mass is also 4:1. Determine the period of revolution of the system if the larger star is 20 AU from the center of the system. . 21)TorF We know the Sun rotates differentially by observing sunspots; as with Jupiter the solar equator rotates the fastest. 22)TorF A type B9 star is hotter than a type A0. 23)TorF On the main sequence, almost all stars have radii between about 0.1 and 10 times the Sun. 24)TorF In a binary system, the less massive star always stays further from the center of mass and moves faster. 25)TorF Two stars have the same spectral type. Star X is in luminosity class III, while Star Y is in luminosity 25) class V. Therefore, Star X is larger in radius than Star Y. 26)TorF Two stars have the same luminosity. Star X 27)TorF Two stars both lie on the main sequence. Star X is spectral type A, while Star Y is spectral type G. Therefore, Star X is more massive than Star Y 28) Hydrostatic equilibrium in our Sun is the balance between . 29) Sunspots 30) Why do sunspots appear dark in pictures of the Sun? 31) A particular star has an absolute magnitude of M=-0.3. Determine the luminosity of the star compared to the Sun and hence which star is a candidate according to HR diagram 1 on the cover sheet? 32) The speed of light is 3.00 × 108 m/s. If 2.00 kg of mass is converted to energy, how much energy will be produced? 33) Sirius is a star with spectral type A star and Rigel is a star with spectral type B star. What can we conclude? 34) The light radiated from the Sun's surface reaches Earth in about 8 minutes, but the energy of that light was released by fusion in the solar core about 35) A loop of gas following the magnetic field lines between sunspots' poles is 36) A star of the Sun's diameter, but twice as hot, must be 16X more luminous than the Sun. 37) According to the inverse square law of light, how will the apparent brightness of an object change if its distance to us triples? 38) The luminosity of the Sun is a measure of 39) The spectral sequence in order of decreasing temperature is