Multiple-Choice Questions
1) Our best stellar parallax measurements to date come from
A) the Hipparcos satellite.
B) ground based measurements taken six months apart.
C) radio interferometry.
D) the Keck telescope.
E) observations made by astronauts.
Page Ref: 10.1
2) A star has a parallax of .05", its distance is
A) 5 light years.
B) 20 light years.
C) 66 light years.
D) 200 parsecs.
E) 660 light years.
Page Ref: 10.1
3) The Hipparcos data give us
A) information on only the 6,000 brightest stars.
B) an accurate distance to the Moon.
C) parallaxes as small as 0.005"
D) distances to about 100 billion stars, practically everything in the Milky Way Galaxy
E) parallaxes to the nearest galaxies.
Page Ref: 10.1
4) Which statement about stellar motion is FALSE?
A) Radial velocity is measured by the Doppler shifts of the spectral lines.
B) Proper motion is measured in intervals of six months.
C) You must also know the parallax to get the transverse velocity.
D) The closer stars usually show larger proper motions.
E) The space velocity can be found from the radial and transverse velocities.
Page Ref: 10.1
5) If spectroscopic luminosity classification gives us an estimated distance to the faint star SAO 47552 of about 3300 light years, then its parallax would be only
A) 3.3".
B) .1".
C) .033".
D) .01".
E) .001".
Page Ref: 10.1, 10.6
6) A star has a parallax of 0.01 arcseconds. Its distance is
A) 0.01 parsecs.
B) 0.1 parsecs.
C) 1 parsec.
D) 10 parsecs
E) 100 parsecs.
Page Ref: 10.1
7) A star is 10 parsecs from Earth. Which statement is true?
A) The star is about 33 ly away.
B) The star is in a different galaxy.
C) The star's apparent magnitude is smaller than its absolute magnitude.
D) The star's apparent magnitude is larger than its absolute magnitude.
E) The star's parallax is 1.0 arc seconds.
Page Ref: 10.1
8) If Vega is apparent magnitude zero, and Deneb first magnitude, then
A) Vega is about 100× brighter than Deneb.
B) Deneb is one magnitude brighter than Vega.
C) Vega is 2.5× brighter than Deneb.
D) Deneb must be a main sequence star, and Vega a giant.
E) Vega must be 2.5× more luminous than Deneb.
Page Ref: 10.2
9) The stars α Cygni and β cygni are in the constellation Cygnus. Which statement is true?
A) α cygni appears brighter.
B) β is hotter.
C) α must be the eastern most star in the constellation.
D) β cygni appears brighter.
E) β appears redder.
Page Ref: 10.2
10) The full Moon's apparent magnitude is
A) +4.83
B) +12.7
C) -1.4
D) -26.2
E) -12.5
Page Ref: 10.2
11) A star's absolute magnitude is its apparent brightness as seen from
A) Pluto.
B) Alpha Centauri.
C) 10 light years distance.
D) 33 light years distance.
E) 100 parsecs distance.
Page Ref: 10.2
12) Rigel has an apparent magnitude of + 0.18 and Betelgeuse an apparent magnitude of +0.45. What can you conclude from this?
A) Rigel must be closer to Earth.
B) Betelgeuse must be closer to Earth.
C) Rigel is brighter than Betelgeuse.
D) Betelgeuse is brighter than Rigel.
E) Both stars are brighter than the full Moon.
Page Ref: 10.2
13) On a night when a human eye can see a fourth magnitude star, a 60mm telescope, with 100× the surface area as our pupil, would be able to just barely detect
A) seventh magnitude Titan, Saturn's largest moon
B) eighth magnitude Uranus
C) ninth magnitude Barnard's Star
D) eleventh magnitude Tethys, Saturn's second largest moon
E) thirteenth magnitude Pluto
Page Ref: 10.2
14) How much brighter will a 4th magnitude star appear than a 6th magnitude star?
A) 6.25×
B) 2.0 ×
C) 2.5×
D) 16 ×
E) 8 ×
Page Ref: 10.2
15) Two stars both have parallaxes of 0.023", but star A has apparent magnitude +2.3, while star B is magnitude +7.3. Which statement is true?
A) Star A must be ten times closer.
B) Star B must be ten times more luminous.
C) Nothing, since we do not know their absolute magnitudes.
D) Star A is both 100× brighter and more luminous than star B.
E) Star A is both 100× brighter and larger than star B.
Page Ref: 10.2
16) The spectral type of a star measures its
A) luminosity.
B) chemical composition.
C) size.
D) temperature.
E) mass.
Page Ref: 10.3
17) Which of these stars would be the hottest?
A) A0
B) B0
C) G2
D) K9
E) M10
Page Ref: 10.3
18) What can be said with certainty about a red star and a blue star?
A) The red star is more massive than the blue star.
B) The blue star is hotter than the red star.
C) The red star has a greater radial velocity than the blue star.
D) The blue star has a greater proper motion than the red star.
E) The red star is closer to Earth than the blue star.
Page Ref: 10.3
19) Which of these pairs of binaries would appear most similar in color telescopically?
A) F0V and G9III
B) M1V and K9V
C) A2Ia and F7Ia
D) O2V and M4Ia
E) F3IV and G8III
Page Ref: 10.3
20) A star's color index directly tells us its
A) temperature.
B) proper motion.
C) distance.
D) radial velocity.
E) age.
Page Ref: 10.3
21) In general, what can be said about type O and B stars compared to type K and M stars?
A) They are hotter and older.
B) They are cooler and older.
C) They are hotter and younger.
D) They are cooler and younger.
E) They are neither hotter nor cooler, younger nor older.
Page Ref: 10.3, 10.7
22) Compared to a type A0 star, a type A9 star is
A) hotter.
B) cooler.
C) bluer.
D) more massive.
E) more luminous.
Page Ref: 10.3
23) The H-R diagram can plot
A) temperature versus mass.
B) radius versus luminosity.
C) temperature versus luminosity.
D) apparent magnitude versus spectral classes.
E) radius versus mass.
Page Ref: 10.5
24) The stars with masses comparable to our Sun's, but sizes like the earth are
A) red main sequence stars.
B) white dwarfs.
C) red giants.
D) blue main sequence stars.
E) neutron stars.
Page Ref: 10.5
25) In the H-R diagram, what are the two most important types of data plotted?
A) absolute and apparent magnitudes
B) apparent magnitudes and temperatures
C) luminosities and masses
D) sizes and temperatures
E) spectral classes and absolute magnitudes
Page Ref: 10.5
26) On the H-R diagram, the bright blue stars that dominate the naked-eye sky lie
A) at the top right.
B) at the top left.
C) in the middle of the main sequence.
D) at the lower right.
E) at the lower left.
Page Ref: 10.5
27) On the H-R diagram, our Sun lies
A) at the top left.
B) at the top right.
C) about the middle.
D) at the bottom left.
E) at the bottom right.
Page Ref: 10.5
28) On the H-R diagram, the white dwarfs Sirius B and Procyon B lie
A) at the top left.
B) at the top right.
C) in the middle of the main sequence.
D) at the lower left of the main sequence.
E) to the bottom right on the main sequence.
Page Ref: 10.5
29) On the H-R diagram, red supergiants like Betelguese lie
A) at the top right.
B) at the top left.
C) about the middle.
D) to the lower left edge.
E) on the bottom, coolest portion of the main sequence.
Page Ref: 10.5
30) Compared to the size of the Sun, stars of all types range from
A) 0.1 to 10 solar radii.
B) 0.5 to 50 solar radii.
C) 0.01 to 1,000 solar radii.
D) 0.08 to 8,000 solar radii.
E) 0.001 to 50,000 solar radii.
Page Ref: 10.5
31) A star near the lower right of the H-R diagram is likely to be
A) red, with high luminosity.
B) blue, with high luminosity.
C) red, with low luminosity.
D) hot, bright, and very large.
E) yellow, with luminosity similar to our Sun's.
Page Ref: 10.5
32) Binary stars separated enough to be resolved in a telescope are called
A) orbital binaries.
B) visual binaries.
C) spectroscopic binaries.
D) astrometric binaries.
E) line-of-sight binaries.
Page Ref: 10.7
33) The Doppler shift is used to find
A) eclipsing binaries.
B) spectroscopic binaries.
C) visual binaries.
D) astrometric binaries.
E) photometric binaries.
Page Ref: 10.7
34) Which type of binaries are best studied with a photometer?
A) eclipsing binaries
B) spectroscopic binaries
C) visual binaries
D) astrometric binaries
E) optical doubles
Page Ref: 10.7
35) If we know the average separation and period of revolution for a binary system, we can then measure
A) the actual sizes of the two stars.
B) the total mass of the system.
C) their absolute magnitudes.
D) the actual mass of both individual stars.
E) the actual luminosity of each star.
Page Ref: 10.7
36) Stellar masses are measured directly by observations of the motions of
A) eclipsing binary systems.
B) spectroscopic binary systems.
C) visual binary systems.
D) All of the above can give us their masses.
E) Stellar masses cannot be measured directly by any method.
Page Ref: 10.7
37) Almost all stars fall in a mass range of
A) 1 to 3 solar masses.
B) 0.1 to 20 solar masses.
C) 0.01 to 100 solar masses.
D) 0.001 to 50,000 solar masses.
E) The range of stellar masses is infinite.
Page Ref: 10.7
38) What information can be gained from the light curves of eclipsing binaries?
A) their distances
B) their masses
C) their sizes
D) their temperatures
E) their luminosities
Page Ref: 10.7