Global View of Axion Stars with (Nearly) Planck-Scale Decay Constants
  We show that axion stars formed from axions with nearly Planck-scale decay
constants $f$ are unstable to decay, and are unlikely to have phenomenological
consequences. More generally, we show how results at smaller $f$ cannot be
naively extrapolated to $f=\mathcal{O}(M_P)$ as, contrary to conventional
wisdom, gravity and special relativity can both become relevant in the same
regime. We clarify the rate of decay by reviewing and extending previous work
on oscillons and axion stars, which imply a fast decay rate even for so-called
dilute states at large $f$.
