Hidden Companions to Nearby Intermediate-mass Stars. I. Discovery of a 0.82M ⊙, 15 au Companion to the Resolved 0.4 au Spectroscopic Binary in HIP 67199* *Based on observations collected at the European Southern Observatory, Chile, Program ID 102.D-0817(C)

Abstract

Further discoveries and detailed studies of close binaries of intermediate-mass stars in hierarchical triple systems are needed in order to understand their formation. Here we report the discovery of a 0.82M ⊙ companion to the intermediate mass spectroscopic binary HIP 67199 at a projected separation of 150 mas ↔ 15 au based on a VLTI/GRAVITY observation. In addition, the spectroscopic binary was spatially resolved with a projected separation 1.70 mas ↔ 0.18 au and inferred masses 1.84M ⊙ + 1.72M ⊙. Further observations can determine the amplitude of eccentricity oscillations in the inner system induced by the third star. HIP 67199 is a potential progenitor for a double white dwarf hiding within the glow of a main-sequence companion.