Final answer:
The requirements for a black hole to form are mass, radius, and compactness. For a binary star to be a good black hole candidate, it must have significant mass and evidence of high-energy emission such as X-rays. Option D is correct.
Step-by-step explanation:
The proper requirements for a black hole to form are mass, radius, and compactness. This makes option D the correct choice. Theory suggests that a stellar core must have a mass greater than three times that of our Sun in order to collapse into a black hole after it exhausts its nuclear fuel.
The boundary around a black hole, known as the event horizon, is where the escape velocity becomes equivalent to the speed of light. The radius of this surface is known as the Schwarzschild radius. Inside a black hole lies a singularity, a point where density is thought to be infinite and volume zero.
When evaluating the potential for a black hole within a binary star system, certain characteristics are crucial for consideration. The mass of the star, its end-of-life nuclear processes, and observations of emitted radiation, such as X-rays, help determine the likelihood of a black hole's presence. High-energy emissions, like X-rays, are indicative of heated matter due to the intense gravitational forces near the event horizon of a black hole.
In terms of centripetal force, which is critical when considering the motion of matter around a black hole, all three elements---mass, speed, and radius---impact the force involved as stated in option D of the given question. It is important to note that numerous binary systems meet the criteria for containing a black hole, and studying such systems involves understanding these physics concepts.