Question

1. Put in order, from earliest to latest, the sequence of events that lead to a star becoming a red giant. If statement A is first, B is second, etc. then enter ABCDEF.

*NOTE* I have already tried CFBEAD and this order is incorrect... Please help because I do not know where I am going wrong.. This is the hint that comes up. HINT: Although many of these things happen at about the same time, for the purposes of this problem, fusion in the shell intensifies slightly before the regions around the core begin new fusion.

A) The increase in total energy prodcution causes the envelope to expand and cool.
B) Regions aroud the core that were previously too cool for fusion to occur now begin fusion.
C) Hydrogen in the core is completely used up and fusion stops.
D) A bigger, cooler and more luminous star has become a red giant.
E) Hydrogen fusion in the shell intensifies due to higher temperatures.
F) The core, without a source of energy, contracts and heats up.

Answer 1

The correct order is :C F E B A D

a brief description of the process is as follows

The fuel in the core of the star is used up and fusion stops.Now core is full of helium

Due to this gravitation dominates in the star and it collapses under gravity

Due to this temperature of the core builds up to a large value even though the fusion is not happening

And due to this high temperature the thin shell of hydrogen around the helium core ignites fusion process (this stage is often called hydrogen shell fusion)

Shortly after this shell fusion startes region around core which were so cool initiates new fusion reactions(the hint)

As the temperature increases,the envelop of the star starts building pressure and so it expands and become cool as it get away from the core

Thus a star becoms a red giant.