2023RNAAS...7..114W

λ Ophiuchi is a nearby 48 au intermediate-mass visual binary with a hierarchical, 6400 au wide companion. We report on the discovery of a close companion to the primary star (Marfik) with a K band flux ratio of 33% at a projected separation ρ = 6.1 mas ↔ 0.32 au based on a VLTI/GRAVITY observation. Isochrone fitting yields masses M_Aa = 2.39M_⊙, M_Ab = 1.62M_⊙ and M_B = 1.82M_⊙. λ Oph therefore joins a growing number of intermediate-mass binaries with 10-60 au separation in which the primary is found to be a close binary and which suggest that many white dwarfs with a main sequence companion at such separations (such as Sirius B) ultimately descended from merger products. In fact, λ Oph is a potential progenitor for a system resembling Sirius.