Formation of the Double White Dwarf Binary PTF J0533+0209 through Stable Mass Transfer?

Abstract Double white dwarf (DWD) binaries are important for studies of common-envelope (CE) evolution, Type Ia supernova progenitors and Galactic sources low-frequency gravitational waves. PTF J0533+0209 is a DWD system with short orbital period P orb ∼ 20 minutes thus so-called LISA verification source. The formation this other DWDs still under debate. In paper, we discuss the possible scenarios binary argue that it not likely to have formed through CE evolution. Applying new magnetic-braking prescription, use MESA code model stable mass transfer. We find can well reproduce observed WD masses but effective temperature hydrogen abundance low-mass He component. possibility using H flashes mitigate discrepancy. Finally, future evolution into an AM CVn such as those will be detected by spaceborne GW observatories like LISA, TianQin, Taiji.