Speaker
Description
White dwarfs with a F, G or K type companion represent the last common ancestor for a plethora of exotic systems throughout the galaxy, though to this point few of them have been fully characterised in terms of orbital period and component masses, despite the fact several thousand have been identified. Gaia DR3 has examined many hundreds of thousands of binary systems, and as such we can use this, in conjunction with previous UV excess catalogues, to perform SED fitting in order to obtain a sample of 206 binaries likely to contain a white dwarf, complete with orbital periods, and either a direct measurement of the component masses for astrometric systems, or a lower limit on the component masses for spectroscopic systems. Of this sample of 206, four have previously been observed with HST spectroscopically in the ultraviolet, which has confirmed the presence of a white dwarf, and we find excellent agreement between the dynamical and spectroscopic masses of the white dwarfs in these systems. In this talk, I will present our findings; that white dwarf plus F, G or K binaries can have a wide range of orbital periods, from less than a day to many hundreds of days. A large number of our systems are likely post-stable mass transfer systems based on their mass/period relationships, while others are difficult to explain either via stable mass transfer or standard common envelope evolution. I will also present preliminary results of expanding this search to a much larger sample.
