Observing white dwarf tidal stripping with TianQin gravitational wave observatory

Abstract

ABSTRACT Recently discovered regular X-ray bursts known as quasi-periodic eruptions have a proposed model that suggests a tidal stripping white dwarf inspiralling into the galaxy’s central black hole on an eccentric orbit. According to this model, the interaction of the stripping white dwarf with the central black hole would also emit gravitational wave signals, their detection can help explore the formation mechanism of quasi-periodic eruptions and facilitate multimessenger observations. In this paper, we investigated the horizon distance of TianQin on this type of gravitation wave signal and found it can be set to 200 Mpc. We also find that those stripping white dwarf model sources with central black hole mass within $10^4 \!-\! 10^{5.5}\, \mathrm{M}_\odot$ are more likely to be detected by TianQin. We assessed the parameter estimation precision of TianQin on those stripping white dwarf model sources. Our result shows that, even in the worst case, TianQin can determine the central black hole mass, the white dwarf mass, the central black hole spin, and the orbital initial eccentricity with a precision of 10−2. In the optimistic case, TianQin can determine the central black hole mass and the white dwarf mass with a precision of 10−7, determine the central black hole spin with a precision of 10−5, and determine the orbital initial eccentricity with a precision of 10−8. Moreover, TianQin can determine the luminosity distance with a precision of 10−1 and determine the sky localization with a precision of 10−2–10 $\rm deg^2$.