will likely have been some mixing of the atmospheric layers. Subsequently, the photosphere cools, while the radius grows, and then, after about $4-5{{\rm\,s}\xspace}$, the rebrightening mechanism activates and quickly thereafter the burst oscillations appear. The photosphere continues to cool, and after about 10[[s]{}]{}both the rebrightening and oscillations switch off.

The flux levels of the pause and peak are highly suggestive that we are seeing both the hydrogen and helium Eddington limits in a single X-ray burst. The evolution of the hardness ratio around the pause further supports the interpretation that this stall in the rise is related to the expanding hydrogen layer. The link between the pause and the dip is weaker, but highly suggestive, and may yet provide the insight required to uncover the physics behind intrinsic rebrightening during the tail of an X-ray burst.

This work was supported by NASA through the [*NICER*]{}mission and the Astrophysics Explorers Program, and made use of data and software provided by the High Energy Astrophysics Science Archive Research Center (HEASARC). P.B. was supported by an NPP fellowship at NASA Goddard Space Flight Center. D.A. acknowledges support from the Royal Society.

, K. A. 1996, in Astronomical Society of the Pacific Conference Series, 