Which of the following is NOT an argument for Cygnus X-1's being a true black hole?
A)Spectroscopic data suggests hot gas is flowing from the companion B star onto Cygnus X-1.
B)The mass of the visible B star is even greater than Cygnus X-1, at around 25 solar masses.
C)Cygnus X-1's mass is estimated to be about 10 solar masses.
D)X-rays from Cygnus X-1 vary on time scales as short as a millisecond.
E)X-ray observations around the object support a temperature of several million K.

Question

Quizplus · Accepted Answer

The mass of the visible companion star being greater than Cygnus X-1 does not argue against it being a black hole. The arguments for Cygnus X-1 being a black hole include evidence of material accretion (A), its mass being above the Tolman-Oppenheimer-Volkoff limit for neutron stars (C), rapid variability in X-ray emissions (D), and high temperatures indicative of accretion disks around black holes (E).

Which of the Following Is NOT an Argument for Cygnus