Stellar Loci XI: Identifications and Parameter Determinations of Binary Stars by multi-band photometry

Large photometric surveys contain numerous unresolved binaries, but identifying them and measuring component properties remains challenging. We present a 65-band UV-to-IR SED-fitting framework to identify unresolved main-sequence binaries and infer their parameters. Photometry combines synthetic miniJPAS magnitudes from corrected Gaia DR3 XP spectra with 2MASS and WISE measurements. Using LAMOST-calibrated, metallicity-dependent stellar loci and a dwarf-star color-absolute-magnitude relation, we construct forward models for single stars and unresolved binaries. We fit both model families to each SED with MCMC, using Gaia distances as Hertzsprung-Russell-diagram constraints to infer metallicity, reddening, and component photometric parameters. Component masses and mass ratios are derived from PARSEC models. Simulations show the method robustly recovers binary parameters. Tests on a LAMOST comparison sample indicate sensitivity to binaries with q0.4; the preferred model reproduces spectroscopic metallicities with 0.11 dex scatter, while inferred reddenings agree with external extinction maps with ~0.02 mag scatter. Comparison with an external Gaia XP-based binary catalog shows broadly consistent binary classifications for common sources. Our metallicities more closely follow the LAMOST spectroscopic scale, and mass-ratio estimates in the intermediate-q regime better trace expected $Δ$-HRD offsets. Tests using M67 members support internal consistency of inferred parameters. For quality-selected Gaia non-single-star binaries, primary-mass estimates agree with Gaia NSS values with 0.071 M_ residual scatter; in cases with larger discrepancies, further tests indicate that secondary-mass and mass-ratio estimates are more reliable than the Gaia NSS values. The method scales to large photometric samples, enabling population studies and analyses of individual systems.