We analyze the infrared structure and memory effects of a massless vector-tensor theory with nonminimal curvature coupling in asymptotically flat spacetimes. Using Bondi-Sachs expansions, we identify the independent radiative data and derive the effective Bondi mass aspect, whose balance law receives an additional positive definite flux from the vector sector. This leads to modified displacement, spin, and center-of-mass memory (CM) expressions, where the gravitational contributions retain their general relativity (GR) form and the vector field enters only through well-defined flux terms. We also describe persistent vector memory effects associated with the leading angular vector mode, which are gauge-invariant but do not affect the leading tidal observables. The Bondi-Metzner-Sachs transformations act kinematically as in GR; tensor vacua remain supertranslation degenerate, whereas the vector vacuum, defined by the vanishing vector field, is nondegenerate. All results reduce continuously to GR when the coupling is removed, isolating the precise channels through which vector-curvature interactions modify the infrared dynamics.

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• Alternative gravity theories
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