Q&A: Miscellaneous X-ray Sources

Q:
What are the chances that the brown dwarf "solar flare" was, instead, an impact by another object similar to the comet that struck Jupiter, creating a massive explosion and not a flare?

A:
That's an interesting suggestion! The energy liberated by a comet infall would be about right, the shock wave might produce high enough temperatures, and the time scale is not unreasonable. The main difficulty is the probability of such an event occurring during a random 12 hour observation.