text:   turning into extremely low-mass white dwarfs",9,"['New paper! We present first results from a survey of compact binary stars with ongoing and just-terminated mass transfer. 1/\n<LINK> <LINK>', 'We select targets from below the main-sequence in the #GaiaMission color-magnitude diagram that have @ztfsurvey light curves dominated by ellipsoidal variability (due to tidal deformation). 2/ https://t.co/HVLOtbWmob', 'This selects objects that (a) are hotter and smaller than normal main-sequence stars, and (b) are dominated a star (the ""donor""), not an accretion disk. We vet targets with spectroscopic follow-up. 3/ https://t.co/zuRSxwUMgC', 'Our final sample of objects lives in a previously (almost) empty region of the HR diagram, between extremely low-mass white dwarfs and main-sequence stars (and ""normal"" cataclysmic variable donors). 4/ https://t.co/mOp0Cft2kt', 'Most of the objects we find are hotter than any previously identified similar objects. We think this is because they have undergone more nuclear evolution. That is,... 5/ https://t.co/WGMSybcN3Z', '... these objects form when mass is stripped off the outside of a star by a white dwarf companion. We think mass transfer began late in these objects, after a helium core had started to form. Today, just the helium core and a thin envelope are left. 6/', 'All the hottest (Teff &gt;~ 7000 K) objects appear to have just ended mass transfer, while the cooler ones still have ongoing mass transfer. We think this means magnetic braking becomes inefficient at Teff &gt;~ 7000 K, when stars lose their convective envelopes, slowing inspiral. 7/', 'This systematic survey allows us to derive a space density and birth rate for these evolved-CVs-turning-into-extremely-low-mass-white-dwarfs. Our inferred birth rate is about half that of the birth rate of ultracompact mass-transferring ""AM-CVn"" binaries. 8/ https://t.co/tsq5vhKKan', 'We think many of these objects will turn into AM-CVn binaries within a few Gyr. The birth rate suggests this channel may be (is likely to be?) one of the dominant formation channels for AM-CVn binaries. \nWe have more observations and analysis of these objects in the works! 9/9.']",21,08,2015