Electromagnetic characterization of the LISA verification binary ZTF J0526$+$5934

TL;DR

This paper characterizes the binary system ZTF J0526+5934, revealing its components, orbital parameters, and predicting its detection by LISA, as well as its potential future evolution and supernova outcome.

Contribution

It provides the first detailed electromagnetic analysis of ZTF J0526+5934, identifying its component masses and predicting its gravitational wave detection and evolutionary fate.

Findings

LISA will detect the binary with SNR 44 after 4 years.

The binary will merge in approximately 1.8 million years.

The merger may produce a Type Ia supernova or a massive white dwarf.

Abstract

We present an analysis of new and archival data to the 20.506-minute LISA verification binary J052610.42$+$593445.32 (J0526$+$5934). Our joint spectroscopic and photometric analysis finds that the binary contains an unseen $M_1=0.89\pm0.11~{\rm M_\odot}$ CO-core white dwarf primary with an $M_2=0.38\pm0.07~{\rm M_\odot}$ post-core-burning subdwarf, or low-mass white dwarf, companion. Given the short orbital period and relatively large total binary mass, we find that LISA will detect this binary with signal-to-noise ratio $44$ after 4 years of observations. J0526$+$5934 is expected to merge within $1.8\pm0.3~{\rm Myr}$ and likely result in a ${\rm D}^6$ scenario Type Ia supernova or form a He-rich star which will evolve into a massive single white dwarf.