Universe Tenth Edition Chapter 17 The Nature of the Stars Roger Freedman Robert Geller William Kaufmann III Clicker Questions

Parallax measurements are best made using a telescope in orbit. This is because A.a telescope in orbit is closer to the stars. B.larger telescopes can be placed in orbit and so the resolution is significantly improved. C.the baseline is longer and so the parallax angle is larger. D.chromatic aberration from the telescope lens is eliminated. E.an observatory in space is unhampered by the Earth ’ s atmosphere. Q17.1

Parallax measurements are best made using a telescope in orbit. This is because A.a telescope in orbit is closer to the stars. B.larger telescopes can be placed in orbit and so the resolution is significantly improved. C.the baseline is longer and so the parallax angle is larger. D.chromatic aberration from the telescope lens is eliminated. E.an observatory in space is unhampered by the Earth ’ s atmosphere. A17.1

The Hipparcos satellite measures a stellar parallax angle of 0.05 arcsec for a nearby star. What is the distance to this star in parsecs? A.0.05 parsecs B.6.1 parsecs C.3.26 parsecs D.20 parsecs E.65.2 parsecs Q17.2

The Hipparcos satellite measures a stellar parallax angle of 0.05 arcsec for a nearby star. What is the distance to this star in parsecs? A.0.05 parsecs B.6.1 parsecs C.3.26 parsecs D.20 parsecs E.65.2 parsecs A17.2

The Hipparcos satellite measures a stellar parallax angle of 0.05 arcsec for a nearby star. What is the distance to this star in light-years? A.0.05 light-years B.6.1 light-years C.3.26 light-years D.20 light-years E.65.2 light-years Q17.3

The Hipparcos satellite measures a stellar parallax angle of 0.05 arcsec for a nearby star. What is the distance to this star in light-years? A.0.05 light-years B.6.1 light-years C.3.26 light-years D.20 light-years E.65.2 light-years A17.3

At the distance of the Earth from the Sun (1 AU) the intensity of sunlight is 1370 watts/m 2. What is the intensity at the distance of Saturn from the Sun (10 AU)? A.13,700 watts/m 2 B.1370 watts/m 2 C.137 watts/m 2 D.13.7 watts/m 2 E.1.37 watts/m 2 Q17.4

At the distance of the Earth from the Sun (1 AU) the intensity of sunlight is 1370 watts/m 2. What is the intensity at the distance of Saturn from the Sun (10 AU)? A.13,700 watts/m 2 B.1370 watts/m 2 C.137 watts/m 2 D.13.7 watts/m 2 E.1.37 watts/m 2 A17.4

How bright is a star with a magnitude of +4.0 compared to a star with magnitude +5.0? A.1/2.5 = 0.4 times as bright B.equally bright C.1.25 times brighter D.2.5 times brighter E.10 times brighter Q17.5

How bright is a star with a magnitude of +4.0 compared to a star with magnitude +5.0? A.1/2.5 = 0.4 times as bright B.equally bright C.1.25 times brighter D.2.5 times brighter E.10 times brighter A17.5

Two stars have the same luminosity. As seen from Earth, star #1 appears four times brighter than star #2. If star #1 is 20 pc away, star #2 A.is 160 pc away. B.is 80 pc away. C.is 40 pc away. D.is 10 pc away. E.is 5 pc away. Q17.6

Two stars have the same luminosity. As seen from Earth, star #1 appears four times brighter than star #2. If star #1 is 20 pc away, star #2 A.is 160 pc away. B.is 80 pc away. C.is 40 pc away. D.is 10 pc away. E.is 5 pc away. A17.6

The spectral classification of a star is closely related to the star ’ s A.apparent brightness. B.absolute magnitude. C.luminosity. D.surface temperature. E.distance. Q17.7

The spectral classification of a star is closely related to the star ’ s A.apparent brightness. B.absolute magnitude. C.luminosity. D.surface temperature. E.distance. A17.7

The spectral type of the Sun is G2 and the spectral type of the star Antares is M1.5. These facts imply that Antares A.has a lower luminosity than the Sun. B.is hotter than the Sun. C.has a higher luminosity than the Sun. D.is cooler than the Sun. E.has the same luminosity and temperature as the Sun. Q17.8

The spectral type of the Sun is G2 and the spectral type of the star Antares is M1.5. These facts imply that Antares A.has a lower luminosity than the Sun. B.is hotter than the Sun. C.has a higher luminosity than the Sun. D.is cooler than the Sun. E.has the same luminosity and temperature as the Sun. A17.8

The spectrum of a certain star reveals that the H and He I absorption lines are equally strong. The surface temperature of this star is approximately A.3000 K B.6000 K C.9000 K D.10,000 K E.20,000 K Q17.9

The spectrum of a certain star reveals that the H and He I absorption lines are equally strong. The surface temperature of this star is approximately A.3000 K B.6000 K C.9000 K D.10,000 K E.20,000 K A17.9

Where is the Sun located on this H-R diagram? A.A B.B C.C D.D E.E Q17.10

Where is the Sun located on this H-R diagram? A.A B.B C.C D.D E.E A17.10

Which stars on this H-R diagram are on the main sequence? A.Vega, Sirius, and Mira B.Stars at letters A and B and Barnard ’ s Star C.Sirius A and Sirius B D.Rigel and Deneb E.Pollux and Barnard ’ s Star Q17.11

Which stars on this H-R diagram are on the main sequence? A.Vega, Sirius, and Mira B.Stars at letters A and B and Barnard ’ s Star C.Sirius A and Sirius B D.Rigel and Deneb E.Pollux and Barnard ’ s Star A17.11

Mira and Barnard ’ s star have different luminosities, as can be seen from the H-R diagram. This difference comes about because Mira has a A.larger diameter than Barnard ’ s star. B.smaller diameter than Barnard ’ s star. C.higher surface temperature than Barnard ’ s star. D.lower surface temperature than Barnard ’ s star. E.the same diameter and surface temperature as Barnard ’ s star. Q17.12

Mira and Barnard ’ s star have different luminosities, as can be seen from the H-R diagram. This difference comes about because Mira has a A.larger diameter than Barnard ’ s star. B.smaller diameter than Barnard ’ s star. C.higher surface temperature than Barnard ’ s star. D.lower surface temperature than Barnard ’ s star. E.the same diameter and surface temperature as Barnard ’ s star. A17.12

Betelgeuse has a very high luminosity (40,000 times brighter than our Sun), but its surface is cool (less than 4000 K). Which of the following explains this? A.Betelgeuse must have a much smaller surface area than the Sun. B.Betelgeuse is at the lower end of the main sequence. C.Betelgeuse is at the upper end of the main sequence. D.Betelgeuse must have a much larger surface area than the Sun. E.Betelgeuse must have the same surface area as the Sun. Q17.13

Betelgeuse has a very high luminosity (40,000 times brighter than our Sun), but its surface is cool (less than 4000 K). Which of the following explains this? A.Betelgeuse must have a much smaller surface area than the Sun. B.Betelgeuse is at the lower end of the main sequence. C.Betelgeuse is at the upper end of the main sequence. D.Betelgeuse must have a much larger surface area than the Sun. E.Betelgeuse must have the same surface area as the Sun. A17.13

A star must be in a binary system to measure its mass. This is because A.single stars are not luminous enough to be measured. B.the mass is calculated from the gravitational interaction between the stars in the system. C.the distance to binary stars can be measured more easily than to single stars. D.stellar diameters can be calculated for all binary stars and the mass can then be determined. E.binary systems are more common than single stars. Q17.14

A star must be in a binary system to measure its mass. This is because A.single stars are not luminous enough to be measured. B.the mass is calculated from the gravitational interaction between the stars in the system. C.the distance to binary stars can be measured more easily than to single stars. D.stellar diameters can be calculated for all binary stars and the mass can then be determined. E.binary systems are more common than single stars. A17.14