An Update on 2 Accreting, Pulsating White Dwarfs in CVs

The cataclysmic variables GW Lib and V386 Ser contain white dwarfs that are located within the instability strip for accreting objects and hence show pulsations. They underwent dwarf nova outbursts in 2007 and 2019 respectively, and were followed observationally to determine the impact of the increased accretion on the pulsation spectrum during the subsequent cooling back to a quiescent state. At the 2020 June AAS meeting, we reported on the unusual behavior of GW Lib (non-monotonic cooling and long pulsation periods compared to quiescence), versus the apparently normal behavior of V386 Ser that matched theory up to that time. We now have several more years of data. Even though GW Lib is now at the point where its quiescent pulsation spectrum was stable prior to its 2007 outburst, it still exhibits its post outburst period. V386 Ser now also exhibits a mode with a period longer than its quiescent one but only by 7 percent. The behavior of these systems shows that the response of the white dwarf to an outburst is not uniform and predictable.