GENERAL KNOWLEDGE

GK

BIG BANG THEORY

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
A small, hot star near the end of its life is a star called a
A
white dwarf
B
red dwarf
C
supergiant
D
protostar
Explanation: 

Detailed explanation-1: -A white dwarf is what stars like the Sun become after they have exhausted their nuclear fuel. Near the end of its nuclear burning stage, this type of star expels most of its outer material, creating a planetary nebula. Only the hot core of the star remains.

Detailed explanation-2: -White dwarfs are stars that have burned up all of the hydrogen they once used as nuclear fuel. Fusion in a star’s core produces heat and outward pressure, but this pressure is kept in balance by the inward push of gravity generated by a star’s mass.

Detailed explanation-3: -A white dwarf is very hot when it forms, but because it has no source of energy, it will gradually cool as it radiates its energy away. This means that its radiation, which initially has a high color temperature, will lessen and redden with time.

Detailed explanation-4: -Stars that have a lot of mass may end their lives as black holes or neutron stars. A low or medium mass star (with mass less than about 8 times the mass of our Sun) will become a white dwarf. A typical white dwarf is about as massive as the Sun, yet only slightly bigger than the Earth.

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