Rachel is a 35 year old school teacher who has no man in her life and lives with her mother.
Each element give off a particular color when heated in a flame. (Some are colorless). Copper gives off a green flame but to do that there must be some copper compound IN the flame. (there are many other elements that also could be causing a green flame).
Because red dwarf stars only burn a little bit of fuel at a time, they are not very hot compared to other stars. Think of a fire. The coolest part of the fire is at the top of the flame where it glows red, the hotter part in the middle glows yellow, and the hottest part near the fuel glows blue. Stars work the same way.