"Fate of this Star" ...Star?

[Ransom]

Star in this context should be world or planet. Our characters aren't living on the surface of a multimillion degree thermonuclear reactor after all. Watch the MST3K episode "Gamera vs Gurion" for why I find this particular mistranslation funny and irritating at the same time.

[Velox]

http://www.merriam-webster.com/dictionary/star

a*(1)*:* a planet or a configuration of the planets that is held in astrology to influence one's destiny or fortune —usually used in plural*(2)*:* a waxing or waning fortune or fame*<her*star*was rising>
b*obsolete*:**destiny

Star can be used for planet. It's simply an archaic definition, but is still correct under the rules of English. Sort of like how the use of 2nd-person "thy, thee, thou, etc." is archaic but still correct.

[RPGpro]

It could also be referring to the entire star system that Hydaelyn resides in. Referring to the planet, moon, star and other planets.
Isn't there some lore that states the first dragons came from space? And Isn't it a dragon that says the specific phrase in question? In which case it's possible that the dragons still recognise Hydaelyn as just a small part of the star system.

Off-note: you wouldn't generally refer to the planet you're currently on as "this planet" but rather "Earth" (that's not technically the name of OUR planet, just a term used to refer to it, if you landed on another earth-like planet you would refer to it as earth too regardless of its correct name).