51.Hypernovae areA.supernovae that occur when two red dwarfs collide.B.supernovae that : 1777249
A.supernovae that occur when two red dwarfs collide.
B.supernovae that occur when 10 solar mass stars explode.
C.supernovae that occur when stars more massive than 25 solar masses explode.
D.one theory to explain the production of gamma ray bursters.
E.both c and d above
52.____ occurs when light travels out of a gravitational field, loses energy and its wavelength grows longer.
A.A gravitational blue shift
B.The solar wind
C.A gravitational redshift
D.A X-ray burst
E.A pulsar wind
53.A _____________ has a radius of about 10 km and is supported by the pressure associated with degenerate neutrons.
54.A neutron star is expected to spin rapidly because
A.they conserved angular momentum when they collapsed.
B.they have high orbital velocities.
C.they have high densities.
D.they have high temperatures.
E.the energy from the supernova explosion that formed them made them spin faster.
55.___________ are neutron stars that have magnetic fields 100 times stronger than the average neutron star.
56.The slowing of clocks in strongly curved space time is known as
D.gravitational red shift.
57.Although neutron stars are very hot, they are faint and not easy to see at visual wavelengths because
A.light does not escape from their event horizon.
B.most lie beyond dense dust clouds.
C.they have only a small surface area from which to emit.
D.the peak of their thermal emission is at much shorter wavelengths than visual
E.both c and d
58.In A.D. 1054, Chinese astronomers observed the appearance of a new star, whose location is now occupied by
B.a neutron star.
C.a supernova remnant.
D.all of the above
59.Pulsars cannot be spinning white dwarfs because
A.white dwarfs are not that common.
B.white dwarfs are not dense enough.
C.white dwarfs do not have magnetic fields.
D.a white dwarf spinning that fast would fly apart.
E.all of the above
60.Pulsars’ rotations are believed to slow down because
A.they are losing angular momentum into space via outward streaming particles
B.they are dragging companions stars around in their magnetic field.
C.they are getting tired
D.of conservation of angular momentum.
E.their mass is increasing.