1. A nova is when nuclear reactions take place on the surface of a(n) 1.neutron star 2.black hole 3.white dwarf 4.main sequence star

2. The region around a graviting object where all material is gravitationally bound is: 1.the detached binary 2.the accretion disk 3.the Roche lobe 4.the supernova remnant

3. The Algol Paradox is called that because 1.the older star has a disk of gas around it 2.the star with the longer lifetime is dying first. 3.the system is an eclipsing system which causes these brightness variations 4.the variations in luminosity are caused by the presence of an accretion disk

4. The shift in the wavelength of spectral lines due to motion of the emitting gas is caused by 1.the accretion disk model 2.the detached binary 3.the superfluid protons 4.the Doppler effect

5. The star Algol is located in the constellation 1.Virgo 2.Perseus 3.Orion 4.Andromeda

6. A disk of gas that is failing onto a star, white dwarf, neutron star or black hole is called a(n): 1.Type Ia supernova 2.Algol binary 3.Hubble spacetime 4.accretion disk