Question 19M.3.SL.TZ2.15b
| Date | May 2019 | Marks available | [Maximum mark: 3] | Reference code | 19M.3.SL.TZ2.15b |
| Level | SL | Paper | 3 | Time zone | TZ2 |
| Command term | Suggest | Question number | b | Adapted from | N/A |
The Hertzsprung-Russell (HR) diagram shows several star types. The luminosity of the Sun is L☉.
Suggest the conditions that will cause the Sun to become a red giant.
[3]
the fusion of hydrogen in the core eventually stops
OR
core contracts ✔
the hydrogen in a layer around the core will begin to fuse ✔
Sun expands AND the surface cools ✔
helium fusion begins in the core ✔
Sun becomes more luminous/brighter✔
Ignore any mention of the evolution past the red giant stage
The evolution of a main sequence star to the red giant region is reasonably well understood. However many struggled to find three different facts to describe the changes. Answers were often too vague, when writing about a change in temperature or size of a star, the candidates are expected to mention whether they are referring to the core or the surface/outer layer. A surprising number of candidates wrote that the Sun must be less than eight solar masses.
