The _________ stars are giant stars fusing helium in their cores and then in their shells.
a. turnoff-point
b. main-sequence
c. turnon-point
d. hydrogen-flash
e. horizontal-branch
Question 2The radio lobes that are on each side of some radio galaxies and jets from them produce mainly
a. 21-cm radiation.
b. synchrotron radiation.
c. black body radiation.
d. emission lies due to hydrogen.
e. absorption lines due to hydrogen.
Question 3Stars within a cluster that are at the turnoff point
a. have life expectancies that are equal to the age of the cluster.
b. are stars that are just becoming white dwarfs.
c. are stars that are just entering the main sequence portion of their evolution.
d. are stars that are about to supernova.
e. are stars that are generally spectral type G stars.
Question 4When discovered in the 1960's, a(n) ___________ was found to emit large amounts of energy, but through visual and radio telescopes appeared to be a single point of light much like a star.
a. a planet like Venus
b. E galaxy
c. spiral galaxy
d. double-lobed radio galaxy
e. quasar
Question 5A(n) _________ is a collection of 105 to 106 stars in a region 10 to 30 pc in diameter. The stars in the collection tend to be more than 109 years old and mostly yellow and red stars.
a. Herbig-Haro object
b. globular cluster
c. open cluster
d. giant cluster
e. supernova