2025ApJ...985..216H

Tidal deformability of a 1.4 M_⊙ neutron star provides a pivotal window into the physics of dense nuclear matter, bridging gravitational-wave (GW), electromagnetic observations and nuclear physics. In this work, we present a novel, data-driven approach to constrain Λ_1.4 without invoking specific equation-of-state (EOS) models. By interpolating directly over the mass-tidal-deformability posteriors from GW170817, we obtain an EOS-independent constraint of ${{\rm{\Lambda }}}_{1.4}\ =\ 222.8{9}_{-98.85}^{+420.33}.$ We further combine these GW-based results with the X-ray EOS-independent constraint from C. Huang, deriving a multimessenger limit of ${{\rm{\Lambda }}}_{1.4}\ =\ 265.1{8}_{-104.38}^{+237.88},$ which remains largely EOS agnostic. This framework demonstrates that higher-order terms neglected in linear expansion methods do not significantly affect Λ_1.4 estimates under current observational uncertainties. As GW detectors improve in sensitivity and more binary neutron-star mergers are discovered, our purely data-driven strategy can serve as a robust standard baseline for extracting neutron-star interior properties without relying on unverified EOS models.