We report the discovery of SDSS J133725.26+395237.7 (hereafter SDSS J1337+3952), a double-lined white dwarf (WD+WD) binary identified in early data from the fifth generation Sloan Digital Sky Survey (SDSS-V). The double-lined nature of the system enables us to fully determine its orbital and stellar parameters with follow-up Gemini spectroscopy and Swift UVOT ultraviolet fluxes. The system is nearby (d=113 pc), and consists of a 0.51M⊙ primary and a 0.32M⊙ secondary. SDSS J1337+3952 is a powerful source of gravitational waves in the millihertz regime, and will be detectable by future space-based interferometers. Due to this gravitational wave emission, the binary orbit will shrink down to the point of interaction in ≈220 Myr. The inferred stellar masses indicate that SDSS J1337+3952 will likely not explode as a Type Ia supernova (SN Ia). Instead, the system will probably merge and evolve into a rapidly rotating helium star, and could produce an under-luminous thermonuclear supernova along the way. The continuing search for similar systems in SDSS-V will grow the statistical sample of double-degenerate binaries across parameter space, constraining models of binary evolution and SNe Ia.
@article{arxiv.2108.11968,
title = {A 99-minute Double-lined White Dwarf Binary from SDSS-V},
author = {Vedant Chandra and Hsiang-Chih Hwang and Nadia L. Zakamska and Boris T. Gaensicke and J. J. Hermes and Axel Schwope and Carles Badenes and Gagik Tovmassian and Evan B. Bauer and Dan Maoz and Matthias R. Schreiber and Odette F. Toloza and Keith P. Inight and Hans-Walter Rix and Warren R. Brown},
journal= {arXiv preprint arXiv:2108.11968},
year = {2021}
}