11.____ of the Milky Way contains mostly old (population II) : 1777257
11.____ of the Milky Way contains mostly old (population II) stars and globular clusters.
A.The disk component
B.The spherical halo component
C.The hydrogen gas in the disk
D.The spiral arms
12.____ in other galaxies should contain luminous O and B stars if they are like the Milky Way.
C.The spiral arms
D.The globular clusters
13.The period-luminosity relation is useful in determining
A.the mass of a star for which the distance is known.
B.the temperature of a star for which we know the luminosity.
C.the radius of the bulge of our galaxy.
D.the distance to globular clusters that contain Cepheid variables.
E.the mass of the Milky Way galaxy.
14.The galactic halo or corona is believed to contain mostly
A.O and B stars.
B.G, K, and M stars.
15.The energy source at the center of our galaxy
A.is not visible at optical wavelengths.
C.must be less than 10 AU in diameter.
D.all of the above
E.none of the above.
16.Who first noticed that for Cepheid variable stars, there was a direct relation between the luminosity and the period of the variation in their brightness?
17.Population II stars
are primarily found in the disk of the galaxy.
contain more heavy metals than population I stars.
are primarily old low mass stars.
are located in globular clusters.
A.III & IV
B.I & II
E.I, II, & III
18.The age of the Milky Way galaxy has been estimated to be at least 13 billion years based on
A.observations of globular clusters.
B.observations of open clusters.
C.21-cm radiation from H I regions.
D.the rotation curve of the galaxy.
E.the energy produced by Sagittarius A*.
19.CO observations of the galaxy reveal
A.the location of dense neutral hydrogen clouds.
B.the location of population II stars.
C.the location of population I stars.
D.the location of the galactic corona.
E.the location of giant molecular clouds.
20.The chemical abundance of population I stars
A.indicates that they were formed before the population II stars.
B.indicates that the material they formed from had been enriched with material from supernovae.
C.indicates that they contain very few heavy metals compared to halo stars.
D.depends on the temperature of the star.
E.depends on the mass of the star.