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tokens: effect, we find that the inclination must be i 58°. Hence, both light curve modeling and analytic estimates require i ≲ 50°otherwise we would see a reflection effect. 3.1. Joint Analysis We now perform a joint analysis that considers our spectroscopic, astrometric, and photometric constraints simultaneously. Our approach is to construct composite binary models by adding two synthetic WD spectra, properly weighted by their respective radii using the astrometric parallax constraint. We then simultaneously fit the spectroscopic Balmer line profiles and the broadband photometric measurements using the Levenberg–Marquardt algorithm (Bédard et al. 2017 ; Kilic et al. 2020 ). We use de-reddened Galaxy Evolution Explorer far-ultraviolet (FUV) and near-ultraviolet (NUV; Martin et al. 2005 ), SDSS ugriz (Abolfathi et al. 2018 ), Pan-STARRS grizy (Tonry et al. 2012 ), and UKIDSS YJ photometry (Lawrence et al. 2007 ). All four atmospheric parameters (, , , and ) are allowed to vary for a given distance. Figure 3 plots the best-fit solution: a 19,000 K DA WD plus a 8000 K DC WD, both with log g = 7. We note that a DA + DA solution yields comparable parameters, but predicts a strong double-lined H α feature that is not observed. The errors in the joint analysis are dominated by the parallax uncertainty. We estimate 1 σ errors of 1000 K in and 0.15 dex in for the DA WD, and 1500 K in and 0.25 dex in for the DC WD. Figure 3. Joint fit to the spectrum (left panel) and photometry (right panel) for the best DA + DC model. The left panel shows the synthetic model (red) overplotted on the observed MMT spectrum (black). The right panel shows the synthetic fluxes (filled circles) and observed fluxes (error bars). The red and blue lines show the contribution of each WD to the total monochromatic model flux, displayed as the black dotted line. We interpolate the atmospheric parameters through the Althaus et al. ( 2013 ) He-core WD tracks to estimate the masses. Conservatively ignoring the co-variance between and , we infer M ⊙ and M ⊙ . Our mass estimates imply that the cool WD may be less massive than the hot WD. The same result is seen in ZTF J1539 + 5027 (Burdge et al. 2019a ). This would be surprising because one expects the cool WD to have evolved first, and thus be more massive than the hot WD. However the models contain a major uncertainty linked to common envelope ejection (Li et al. 2019 , 2020 ). The thickness of the WD hydrogen envelope, assumptions about elemental diffusion and rotational mixing, the presence or absence of hydrogen shell flashes, and other issues have significant effects on the temperature, radius, and cooling age of a low-mass WD (Althaus et al. 2013 ; Istrate et al. 2016 ). To draw a significant conclusion about the WD masses and their past evolution, we need to improve our constraints, i.e., with future GW measurements. The present constraints are also consistent with J2322 + 0509 being an equal-mass binary. Given the mass