In a new paper, I argue that this exomoon is really what is called a captured planet.
Is the first detected ‘exomoon’ really a moon?
True Earth analogues, that orbit Sun-like stars, are very hard to detect, even with the large Keck telescopes. The task is easier if the host star is less massive. But then the planet has to be closer to the star to be warm enough, and the star’s gravitational tides may trap the planet in a state with a permanent hot side and a permanent cold side. This makes such planets less attractive as a potential location that could harbor life. When gas giants orbiting Sun-like stars have rocky moons, these may be more likely places to find life.