Why does the main sequence have a limit at the lower end?
A)Low mass stars form from the interstellar medium very rarely.
B)Low mass objects are composed primarily of solids, not gases.
C)The lower limit represents a star with zero radius.
D)A minimum temperature is required for hydrogen nuclear fusion to take place.

Question

Quizplus · Accepted Answer

The minimum temperature required for hydrogen nuclear fusion to take place in the core of a star is about 10 million degrees Kelvin. At temperatures below this, the fusion reactions do not occur at a rate sufficient to sustain the pressure and temperature needed to balance the force of gravity. This sets a lower limit to the mass of a star. Therefore, the correct option is (D).

Why Does the Main Sequence Have a Limit at the Lower