No nuclear reactions occur in the interior of a white dwarf. its brilliance comes from stored heat. therefore, the fate of an isolated white dwarf is to slowly lose its stored energy and dim over a long period of time. however, if a white dwarf is a member of a binary-star system with specific properties, the white dwarf can become explosively active. label the components of such a binary-star system capable of producing a nova event.
a. mass-transfer stream
b. accretion disk
c. main-sequence or giant companion star
d. white dwarf

According to results from such experiments and its likes, it is known that for a white dwarf to become explosively active, the distance between the dwarf and the companion must be small enough that the white dwarf's gravitational field can pull matter away from the surface of the companion. Due to the rotation of the binary system, the matter flowing through the mass transfer stream from the companion star forms a flattened disk which is called an accretion disk which orbits around the white dwarf.

hopemichael95 hopemichael95 · Answer 2 · 2020-04-14T03:59:04+02:00

Answer: B

Explanation:

According to results from such experiments, it is known that for a white dwarf to become explosively active, the distance between the dwarf and the companion must be small enough that the white dwarf's gravitational field can pull matter away from the surface of the companion and this can only occur with an accretion disc ( remember that accretion is a process of a growth of a massive object by gravitationally attracting and collecting of additional material). Due to the rotation of the binary system, the matter flowing through the mass transfer stream from the companion stars forms this flattened disk which is called an accretion disk which orbits around the white dwarf (this happens through a disk-like structure of diffuse material or gas that is in orbital motion around the central accreting object). Current theory suggests that dwarf novae result from instability in the accretion disk, when gas in the disk reaches a critical temperature that causes a change in viscosity, resulting in a temporary increase in mass flow through the disc, which heats the whole disc and hence increases its luminosity making it explosively active.