Our best knowledge of physics predicts that the Sun is powered by the nuclear fusion of Hydrogen into Helium via the pp-chain. The story of how we tested this model by detecting, here on Earth, the neutrinos from the fusion process deep in the core of the Sun, is a fascinating one which has only reached a conclusion very recently. It is a great case study in astronomy.
The first research project will be to research this story and write it up in the form of a concise, 1500 word article whose level, language and structure would be appropriate for a popular science article (e.g. for a magazine such as Scientific American). Pictures/diagrams can be included as required. All sources should be fully cited.